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- Creator:
- Hernandez, Trang Manny
- Description:
- There is a possibility to eradicate infectious diseases with antibiotics. However, new infectious diseases are continually being identified and some known pathogens are again becoming a threat because of antibiotic resistance. Amphibians mostly live in a moist environment which is the best condition for the growth of bacteria and fungi as well. Antimicrobial peptides produced by serous glands in the amphibian skin play a key role in limiting microbial growth and preventing infections with pathogenic microorganisms. In addition to the antimicrobial peptides produced by serous glands, microbial symbionts on the bullfrog skin are also a source of antimicrobial peptides that can protect the amphibian against diseases. In this research, we investigated whether cutaneous bacterial species isolated from Rana catesbeiana (North American Bullfrog), an amphibian species that is resistant to chytridiomycosis, produce secondary metabolites that could be used to inhibit the growth of three species of dermatophytes (Microsporum gypseum, Epidermotphyton floccosum, Trichophyton mentagrophytes) which are known to cause skin infections in humans. The isolated bacterial species from R. catesbeiana may be useful as producers of antifungal metabolites that kill, or inhibit the growth of, dermatophytes known to cause topical or subdermal skin infections in humans.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Bakersfield
- Department:
- Biology
- Creator:
- Lewis, Ryan D.
- Description:
- Purpose of the Study: The endangered Sonoma County population of the California tiger salamander, Ambystoma californiense, undergoes migrations between breeding pools and upland dry-season refugia. Orientation in this species during breeding migrations has been addressed minimally in previous studies, and literature is particularly sparse concerning newly metamorphosed juveniles. Previous works have not addressed the ability of metamorphs to orient or the way in which they search for upland refugia. The purpose of this study is to evaluate if California tiger salamander metamorphs can re-orient during initial migration and if search movements constitute a Correlated Random Walk. Procedure: We evaluated fine scale movements of newly metamorphosed California tiger salamanders as they moved away from breeding pools, by capturing salamanders with a drift fence. Metamorphs received different orientation treatments, and subsequent movement was tracked with fluorescent powder. We measured turning angles and step lengths at each segment of the tracks, and compared the effect of different treatments. Findings: Here we show that newly metamorphosed juveniles can re-orient to their upland migration path after being interrupted and disoriented. Further, we demonstrate that while searching for burrow refugia, metamorph movement is a correlated random walk. Conclusions: The initial migration from natal pools to uplands following metamorphosis has been identified as a crucial life history juncture for the persistence of this species. Our findings show that these migrations are directed by some orientation, and that these movements are not random. The presence of a Correlated Random Walk is consistent with search patterns in many vertebrates.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Sonoma
- Department:
- Biology
- Creator:
- Grimes, Adam John
- Description:
- The blunt-nosed leopard lizard (Gambelia sila) is a federally and state-listed endangered species, endemic to the San Joaquin Valley, Carrizo and Elkhorn Plains, and Cuyama Valley of central California. Habitat degradation has had a profound impact on the historic distribution and population size of G. sila. Although recognition of G. sila as a distinct species has been questioned by some authors (e.g., Cope 1900, Smith 1946), it is currently recognized as a full species separate from the wide-ranging long-nosed leopard lizard (G. wislizenii); however, genetic support for the specific status of G. sila is lacking. Furthermore, the genetic identity of leopard lizards in the purported hybrid zone between these two species in the Cuyama Valley in Santa Barbara and Ventura counties has not been evaluated using modern molecular techniques. Understanding the genetic identity of leopard lizards in the Cuyama Valley has practical as well as systematic implications. I investigated the sister taxon relationship of G. sila and G. wislizenii using 603 base pairs of sequence from the mitochondrial cytochrome oxidase III (CO3) gene from 37 individuals representing the two species sampled from various populations in western North America. Phylogenetic analysis revealed 17 haplotypes that are partitioned into two major clades that correspond to the range of G. sila and that of G. wislizenii haplotype groups, thus supporting the recognition of both lizards as distinct species. Additionally, I sequenced 682 base pairs of the mitochondrial cytochrome oxidase b (cyt b) gene from 34 individuals representing six populations of G. sila, including lizards from a remnant hybrid population. Phylogenetic analysis indicated that the cyt b sequences consisted of 18 haplotypes that are partitioned into three geographic clades: northern, central, and southern. All lizards from the Cuyama Valley exhibited the G. sila mitochondrial DNA signature and formed the "southern" clade that was joined as a sister group to the "central" clade. My morphological analysis placed some leopard lizards from the hybrid zone with true G. sila, whereas some aggregated with G. wislizenii, indicative of hybrid status. However, genetic signatures suggest that all lizards in the hybrid zone are true G. sila, and not hybrids.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Bakersfield
- Department:
- Biology
- Creator:
- Tennant, Erin Nicole
- Description:
- The Tipton kangaroo rat (Dipodomys nitratoides nitratoides), is an endangered subspecies of the San Joaquin Valley kangaroo rat, found in the Tulare basin of the San Joaquin Valley. Dipodomys n. nitratoides and the larger Heermann’s kangaroo rat (Dipodomys heermanni) are often found sympatrically throughout the San Joaquin Valley. However, potential competitive interactions and the nature of population fluctuations between these two species are largely unknown. Because I thought that D. heermanni could be negatively affecting a translocated population D. n. nitratoides on Allensworth Ecological Reserve, Tulare County, California, I initiated a study on potential competitive interactions between these two species. In this study my objectives were to (1) determine whether the presence of D. heermanni affects space use and foraging behavior of D. n. nitratoides and (2) compare D. n. nitratoides abundance and population trends between areas with and without D. heermanni. I found that in an exclusion area where D. heermanni were removed, D. n. nitratoides increased exponentially since the start the study, whereas on a control site with both species, D. n. nitratoides decreased significantly. My results suggest that D. heermanni are competitively depressing a population of translocated D. n. nitratoides on the study site. Furthermore, eliminating competitive effects of larger, coexisting species during reintroduction or translocation efforts for D. n. nitratoides may be an important factor in success. To further test optimal translocation and reintroduction methods for protected kangaroo rats in the San Joaquin Valley, possibly an important conservation strategy, I translocated the group of non-protected D. heermanni that was removed from the exclusion area during the competitive interactions part of my study. During this part of my research, my objective was to determine whether soft-release methods, which involve a 30-day acclimation period in a wire mesh cage, help to improve survivorship of translocated kangaroo rats. My results indicated that hard-released individuals had higher survivorship than soft and semi soft- released individuals. I believe that one of the factors that may have contributed to the success of hard-released individuals was the high number of available burrows on the translocation site, often not found at sites, which provided refugia for translocated individuals. ii
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Bakersfield
- Department:
- Biology
- Creator:
- Keldgord, Heather Elayne
- Description:
- Rhus ovata is an evergreen shrub species that is common to low elevations in southern California. This species is subdioecious, i.e. some individuals are functionally females and produce fruit while others are functionally male and produce flowers with pollen. I hypothesized that because female plants allocate greater resources to reproduction through the formation of both flowers and fruit, female plants have fewer resources available for vegetative growth, survival, and defense. Therefore, I predicted that female plants would be smaller and less competitive. I sampled Rhus ovata populations at six sites across a rainfall gradient (221mm/yr to 701 mm/yr) and predicted that populations would be male dominated at drier sites because of their greater stress tolerance. At each site I measured the ratio of male to female plants within the sampled population. For a subset of individuals at each site, I measured crown size, stem tissue density, specific leaf area, reproductive investment, and distance to the nearest neighbor. As expected, female plants had greater total reproductive investment although the amount of investment was highly variable and females exhibited more variability than males. However, this differential reproductive investment did not lead to sexual size dimorphism. Ratios of functional male plants to functionally female plants differed among sites, but these differences were not correlated with rainfall and across sites the ratio of males to females did not significantly differ from a one to one. Plasticity in allocation to reproduction among females in this long-lived woody species may mitigate reproductive costs and reduce sexual dimorphism.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Bakersfield
- Department:
- Biology
- Creator:
- Atwood, Robert Christopher
- Description:
- Opuntia basilaris Engelm. & Bigelow var. treleasei (J.M. Coult.) Toumey (OBT), commonly known as Bakersfield cactus, is endemic to parts of Kern County, California. O. b. var. treleasei is one of four varieties of Opuntia basilaris and is state and federally listed as endangered (USFWS 1990). The purpose of this study was to assess the genetic differentiation between OBT and Opuntia basilaris var. basilaris (OBB), and within and among populations of OBT throughout its range. Samples were collected from 200 individual plants representing 32 populations of OBT and one population of OBB and were analyzed using amplified fragment length polymorphisms (AFLP). The AFLP protocol was successfully used to differentiate between an outgroup population of OBB and the great majority of the sampled populations of OBT using 195 polymorphic fragments. Two dendrograms were created using unweighted pair group method with arithmetic mean (UPGMA); one for all individuals and the other where each population was treated as a discreet unit. In the dendrogram based on all individuals, most samples did not cluster as distinct geographic populations, suggesting little genetic differentiation, due to a partial or complete restriction of gene flow, among the majority of OBT populations. Extensive genetic variation was found within and among OBT populations based on an analysis of molecular variance (AMOVA). Twenty three percent of the genetic differentiation was found among fragmented populations and 77%from within individuals of OBT populations suggesting that genetic variation exists between individuals within the OBT populations analyzed. In the UPGMA diagram by population, all five of the Wheeler Ridge populations clustered together. Moreover, three of the Wheeler Ridge populations formed a distinct cluster in a principal coordinates analysis (PCoA) suggesting some level of genetic structure among OBT populations. The only population with a large sample size where virtually all representative samples grouped together was for ‘OEO2’, which is located in the eastern portion of the Southern San Joaquin Valley. The results of this population genetics study will likely be useful in the conservation management of this endangered taxon.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Bakersfield
- Department:
- Biology
- Creator:
- Castaneda, Alejandro Realivazquez
- Description:
- The purpose of this study is to investigate the level of genetic divergence among populations of Vaejovis confusus in the southern San Joaquin Valley and across the state of California. Although there has been considerable research to measure genetic variation among and within scorpion species, little work has been done to investigate the impact of anthropogenic factors on genetic variation within populations. Anthropogenic factors such as man-made barriers can fragment populations and may serve as mechanisms of reproductive isolation. Particularly in the southern San Joaquin Valley, vast arrays of canals and artificial channels have been constructed to divert water from the Kern River for agricultural purposes. In the southern San Joaquin study, the level of genetic divergence is examined in a fragmented population as a result of an anthropogenic barrier, the California Aqueduct, at Coles Levee Ecosystem Preserve. Sequencing of the mitochondrial 16S ribosomal RNA gene in 20 Vaejovis confusus individuals of each fragmented population was performed. Neighbor-joining and maximum parsimony analysis of DNA sequences elucidated the level of genetic divergence. For comparison, an identical analysis was performed across a natural barrier, the Kern River at the Panorama Vista Preserve, which has separated Vaejovis confusus populations for a much longer period of time. The results of this study showed the presence of five haplotypes at the Coles Levee Ecosystem Preserve, with three haplotypes common to both sides of the California Aqueduct. Similarly at Panorama Vista Preserve, five haplotypes were found, with two haplotypes shared at both field sites across the Kern River. These results indicate that scorpion populations across the California Aqueduct and Kern River are not genetically partitioned, despite the isolating effect of these barriers. The existence of the California Aqueduct for over 50 years is not enough time to cause genetic divergence among fragmented populations. The occasional drying of the Kern River may promote gene flow between the populations or amount of time after reproductive isolation may be insufficient to cause evolutionary divergence between the two populations. In the California analysis the mitochondrial 16S rRNA gene is examined in 22 individuals from 9 counties to determine the effects of isolation by distance on the geographic-genetic structure of Vaejovis confusus populations. Scorpions were obtained from a collection of samples from the California Academy of Sciences, San Francisco. Neighbor-joining and maximum parsimony analyses were used to resolve the level of evolutionary relatedness among the populations of Vaejovis confusus throughout California. Fourteen haplotypes were found in this analysis. Eleven haplotypes were unique to their field site, whereas three were common across the state across large geographic distances (approximately 350 miles). Mitochondrial markers found high genetic variation (9.6%) in this species. Nearly half (154/325) of pairwise distance comparisons showed a 2.0% or higher sequence divergence and supported an overall isolation by distance effect. The occurrence of three haplotypes across the state results in a weak association between geography and genetic structure of V. confusus. Notably however, there is some geographic partitioning between haplotype D common in western California and haplotypes A and C common in eastern California. However, the overall lack of genetic partitioning with respect to geography among the California populations is likely due to an insufficient amount of elapsed time to promote genetic differentiation.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Bakersfield
- Department:
- Biology
- Creator:
- Hayes, Christine C.
- Description:
- The phorid fly genus Apocephalus is the largest assemblage of ant-parasitizing Phoridae. Apocephalus is currently organized into two subgenera: A. (Apocephalus) and A. (Mesophora). The species of A. (Mesophora) attack a wide variety of non-ant hosts including stingless bees, spiders, wasps, bumble bees, and cantharoid beetles. The species of A. (Apocephalus) are the true “ant-decapitating flies” and are divided into six species groups: the A. attophilus group (parasitoids of attine leaf-cutting ants), “A. miricauda group” (parasitoids of ponerine ants), A. pergandei group (parasitoids of Camponotus carpenter ants), A. mucronatus group, A. feeneri group, and A. grandipalpus group. Here I report on a preliminary molecular phylogenetic study of Apocephalus, including representatives of both subgenera and exemplars of five currently recognized species groups. Maximum parsimony, maximum likelihood, and Bayesian phylogenies were inferred using four nuclear (AK, TPI, CAD, 28S) and four mitochondrial (12S, 16S, COI, ND1) gene fragments (4284 bp total). For all analyses Apocephalus was recovered as a monophyletic group relative to the outgroup taxa included in the study. In addition, subgenus A. (Mesophora) was recovered as a monophyletic group, but was not a sister group to the subgenus A. (Apocephalus).A phylogenetic hypothesis for exemplars of five Apocephalus species groups is presented and compared to hypotheses based on morphology.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Bakersfield
- Department:
- Biology
- Creator:
- Duquette, Marc Roland
- Description:
- With over 1,300 known species, the genus Megaselia Rondani is the largest phorid genus, largely the result of high cryptic diversity and a past tendency for researchers to lump species into the genus that defied convenient classification. For many of these species, little information is available beyond one or two morphological characters. The first molecular study of such a species, Megaselia sulphurizona Borgmeier, is presented here. New sequence data from two mitochondrial loci (cytochrome oxidase, COI; NADH 1 dehydrogenase, ND1) for a total of 792 bp were obtained from 22 M. sulphurizona specimens collected from four populations in California, plus 12 other phorid taxa using standard DNA extraction and PCR techniques. Neighbor-joining, maximum likelihood, and maximum parsimony analyses revealed M. sulphurizona to be a cryptic species complex, constituting three distinct species in the Riverside, Monrovia, and Bakersfield/Tehachapi areas. These findings suggest greater cryptic diversity within M. sulphurizona, and have broader implications for phorid biodiversity.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Bakersfield
- Department:
- Biology
- Creator:
- Blackhawk, Nicole Cherri
- Description:
- The Giant Kangaroo Rat (Dipodomys ingens) is a federally and state-listed endangered species, endemic to the San Joaquin Valley, Carrizo and Elkhorn Plains, and the Cuyama Valley. Populations of the endangered Giant Kangaroo Rat (Dipodomys ingens) have decreased over the past 100 years because of habitat fragmentation and isolation. Changes in the population structure that can occur due to habitat fragmentation can significantly affect the population size and the dispersal of these animals. Dr. David Germano and I collected small ear clippings from male and female Giant Kangaroo Rats from six sites along the southern San Joaquin Valley to determine the genetic population structure of this species in this part of their range. We predicted that geographic distance and isolation of populations would decrease genetic relatedness compared to populations closer together. Having a better understanding of the genetic structure in this species will help with conservation actions, such as translocating individuals within the range of the species. These data were compared to published estimates of genetic diversity of Giant Kangaroo Rats in the Carrizo Plain to the west and the Panoche area to the north, the other large population centers of this species.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Bakersfield
- Department:
- Biology
- Creator:
- MacKinnon, Evan D.
- Description:
- Non-native grass invasion is a major concern for land management and native plant conservation. In the southern San Joaquin Valley of California, human-disturbed environments that are heavily invaded by non-native grasses often contain some native annual species. These “weedy” native species apparently have the functional traits and life history characteristics to compete and persist in disturbed and invaded landscapes. We categorized several native plants into either a weedy or non-weedy habit based on several criteria, and confirmed this habit designation using a field trial where we controlled for other factors likely to influence species abundance under field conditions. We then measured functional traits for a group of five non-weedy species that occur locally but are not abundant in invaded areas, to a group of four weedy plant species that included the invasive grass red brome. We hypothesized that a suite of functional traits would define the weedy plant habit. We examined this hypothesis in a specific community, where we compared functional traits between weedy and non-weedy plant habits, and between native species and red brome. A principal components analysis (PCA) identified three distinct ecological clusters among the analyzed species (weedy native forbs, non-weedy native forbs, and grasses), and suggested the presence of a weedy functional type. Weedy species were different from non-weedy species in several traits (larger leaf area investment, larger root biomass allocation, heavier diaspores, and dormant seeds requiring cold-stratification for germination). The PCA suggested complementarity as an explanation for the co-occurrence of weedy native species and red brome, but individual trait similarities and a competition experiment suggested that competition can occur for some resources. Further understanding of the traits shared among weedy native plant species may lead to cost-effective approaches to restoring invaded landscapes.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Bakersfield
- Department:
- Biology
- Creator:
- Turnbull II, John
- Description:
- Examination of fish skeletal remains from archaeological sites serves both archaeological and biological interests. For archaeologists, it can establish the role of fish consumption in a people’s diet, provide clues to their fishing technology and overall maritime capability, and even suggest movement patterns and settlement (Rick et al. 2001, Erlandson et al. 2008, Des Lauriers 2010). Analysis of fish bones from excavations on San Miguel Island, of the southern California coast, suggested use of boats and early evidence of hook-and-line fishing techniques, concurrent with an estimate that fish comprised over 50% of the edible meat for the early islanders (Rick et al. 2001). Fishbone identifications have contributed to determining where early Paleocoastal peoples settled, to indicating occupation in some areas earlier than previously thought, and to suggesting that at least some southward Pacific coastal migration in North American may have been by sea (Erlandson et al. 2008). For ichthyologists, identifications of fish remains provide a historical or prehistorical survey of fishes in an area, and with comparison to modern surveys of those same areas, provide bases for examining fish distribution, fish diversity, and marine habitats over time (Gobalet 2000, Salls 2000, Erlandson et al. 2008). In supporting Point Conception, California, as a landmark for a marine faunal break, Gobalet (2000) compared the distribution of fishes identified from the archaeological record to their current distributions. Salls (2000) used bone identifications from archaeological sites on Southern California’s San Clemente Island to describe probable offshore habitats for as early as 9,000 calendar years before the present (cal BP). For over a decade, archaeological excavations on Cedros Island, which lies off the Pacific coast of the Baja California peninsula, have unearthed evidence of early colonization in the Cedros area, with implications for Paleo-human migrations (Des Lauriers 2010). Unfortunately, no on-site scientific survey of the fishes or marine habitats at Cedros Island has been published against which to compare fishbone analysis, but modern surveys of the waters close to Cedros Island exist and can be useful. Regarding habitats, Quast (1968), Engle (1993), and Bond et al. (1999) represent influential earlier studies that established the use of fish species associated with specific habitats. More recent marine faunal surveys that included the Cedros marine environment (but not specifically Cedros Island) also describe fish assemblages associated with habitats. Stephens et al. (2006) examined such associations for the rocky reef/kelp bed habitats of the southern San Diego Province, as did Pondella II et al. (2005) for the San Benito islands that lie close to Cedros. Allen and Pondella II (2006) provided a comprehensive ecological review of the California coast south to central Baja and identified fish species associations with a wide range of habitats. In this thesis, I report the identifications of fish bones from archaeological excavation sites on Cedros Island. The archaeological investigation indicates the settlement of the area about 12,000 cal BP and the establishment of a society that existed into the 18th century of our current era (CE; Des Lauriers 2005, 2008, 2010). These identifications then are provided to assist this investigation on Cedros in its efforts to better understand the Cedros islanders and to lend some insight as to the types of fishes they harvested and the predominant habitats those fishes represented.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Bakersfield
- Department:
- Biology
- Creator:
- Madsen, Angela
- Description:
- Ecological interactions can vary in strength depending on environmental conditions. The outcomes of these interactions are often dependent on the abiotic environment, but can also depend on the presence of other biotic species, including mutualists, which can further alter these effects due to trade-offs in nutrient allocation for multiple interactions. For example, some plants produce extrafloral nectar, a specialized nectar used to attract ants that will defend the plant against herbivory. If plants with extrafloral nectaries also have a second mutualistic relationship with the soil bacteria rhizobia, this second mutualism has been shown to alter the attraction of ants to the extrafloral nectar of the plant. This change in ant attraction could be caused by changes in nectar production or nectar composition, although the exact reason is unknown. Plants do alter extrafloral nectar production and composition for other reasons, for example if a plant is experiencing herbivory the plant will increase the quantity of the extrafloral nectar which will attract more ants. What is not well understood is what specific changes to the nectar, if any, cause it to become more attractive or if the attraction is simply due to a higher quantity of the extrafloral nectar. In my thesis research I explored how the chemical composition of extrafloral nectar, specifically nectar quantity and sugar, is affected by rhizobia mutualists, soil nutrients, and herbivory. Moreover, I explored how these changes influence the ant community and herbivorous arthropod community, as well as plant traits and overall fitness of the Vicia faba plant and its associated mutualistic rhizobia. I tested the effects of these factors through a series of greenhouse and field experiments, running the extrafloral nectar through a total carbohydrate assay to quantify carbohydrate (i.e. sugar) content. I found that under most conditions, the composition of the extrafloral nectar remained constant. However, when plants associated with the soil bacteria rhizobia, the rhizobia mutualism caused a decrease in sugar content in extrafloral nectar but increased the overall quantity of extrafloral nectar produced when outside of herbivory pressure. The reason for this could be due to limited resources, as the plant has a finite amount of carbon and has to allocate this carbon to both the extrafloral nectar and to rhizobia. This need for resource allocation and the altered quantity and composition of extrafloral nectar had no effect on plant fitness traits nor on ant or arthropod visitation in my study, although so few ants were present that conclusions on ant visitation effects cannot be made. These results allow for other new and exciting questions in plant and insect ecology, such as what effect these resource allocations have on plant competition, growth, fitness, and how it impacts the broader ecological community.
- Resource Type:
- Masters Thesis
- Identifier:
- 10091
- Campus Tesim:
- Bakersfield
- Department:
- Biology
- Creator:
- Castro, Viridiana
- Description:
- Transporting water efficiently is one of the chief functions of plant vascular systems. Highly efficient transport is generally beneficial; however, tradeoffs arise because vascular systems have multiple functional roles that interact with one another. One example of a tradeoff may be related to how plants respond to water deficits. Some plants growing in arid and semi-arid environments form xylem networks that are able to tolerate water deficiencies and cope with embolism spread. Distinguishing patterns in embolism spread is important to understand how plants are vulnerable to water stress and what tradeoffs are involved in water stress resistance. Flowering plants found in mediterranean-type ecosystems differ in conduit (vessels and tracheids) presence and abundance. Little is known about how embolism spreads in plant vascular systems and the role tracheids play in the spread of emboli in vessel-bearing plants. I hypothesized that patterns in vessel embolism spread are linked to the type of conduit connections. I assumed that the propagation of embolism most commonly occurs through vessel-to-vessel connections. Therefore, I predicted that the presence of tracheids minimizes embolism spread compared to species with only vessels that have greater numbers of vessel-to-vessel connections. By contrast, greater vessel-to-vessel connections promote greater hydraulic transport efficiency. To test this hypothesis, I quantified embolism spread using computer assisted tomography (microCT) and hydraulic efficiency (hydraulic conductivity per unit xylem area; Ks) in six different species of woody plants that differ in tracheid presence, vessel structure, and hydraulic function. In Chapter 1, I briefly review how plants respond to water stress and what effects have been noticed to occur within their xylem conduits as a result. In Chapter 2, I present microCT, hydraulic efficiency, and percentage loss in conductivity (PLC) results from dehydration treatments for six species native to mediterranean-type climate regions in California, Cercoparpus betuloides, Malosma laurina, and Heteromeles arbutifolia; and the Mediterranean Basin, Laurus nobilis, Olea europaea, and Cistus ladanifer. In Chapter 3, I summarize my findings in the broader context of plant vascular function. My chief conclusion is that the connections between vessels are a key determinant of the tradeoff between hydraulic safety from cavitation and transport efficiency.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Bakersfield
- Department:
- Biology
- Creator:
- Stevens, Samantha K.
- Description:
- Purpose of the Study: The Russian River watershed stretches across a significant portion of Sonoma and Mendocino counties, covering 1,485 square miles, and is home to not only humans, but countless fish and wildlife species as well. The Russian River valley is famous for being an ideal place to grow wine grapes and other agriculture, in part for its fertile soil, as well as the region’s Mediterranean climate. In addition to this, the Russian River is a year-round recreational hotspot for both tourists and locals alike. Maintaining a high quality of water in any area is important, and this is especially true when the local economy relies so heavily upon surface water. According to the North Coast Regional Water Quality Control Board, the entire Russian River watershed is impaired for sediment and temperature, and recent data also show pathogen impairment throughout the watershed. The Laguna de Santa Rosa sub-watershed is also impaired for phosphorus and dissolved oxygen, in addition to the impairments throughout the watershed (Russian River Watershed Overview, 2019). Land uses and water quality are interconnected in the Russian River watershed, but causal patterns between the two are not well understood. Procedure: Water quality data was obtained via the United States Geological Survey (USGS) and input into Microsoft Excel to generate time series graphs of different water quality constituents. The three sites selected are Jimtown, Digger Bend, and Hacienda Bridge. A model from the USGS ScienceBase inventory was utilized for this project, which consists of future land use, land cover, and population projections for the state of California for the period of 2001-2101. This model was projected as a layer in ArcGIS Pro in order to estimate the land cover changes based on low, medium, and high population projections for the years 2050 and 2100. In order to estimate the nutrient input for these different scenarios, models were constructed using WikiWatershed’s Model My Watershed tool. Within Model My Watershed, the land cover was altered to emulate the six models by adding polygons of the desired land cover, running the model, and observing the resulting nutrient and total suspended sediment load output. An additional aspect of this project is to conduct an analysis of policies. Findings: As land is developed into managed cropland, nutrients are typically added in order to increase production and profit. As a result, the runoff from cropland is typically nutrient rich when infiltration rates are low. Records from the Sonoma County Crop Reports indicate that the acreage of vineyards nearly doubled between 1990 and 2000. The exploration of potential land use and land cover changes through the projection of the USGS ScienceBase layers in ArcGIS and the modeling of nutrient load in Model My Watershed showed both an increase in agricultural land use as well as an increase in nutrient load, which is expected. The data obtained from the USGS Water Quality monitoring site did not show many points of interest or concern and generally followed a seasonal pattern. The policies in place in Sonoma County regulate both point source and non point source pollution, which is an extremely effective way to minimize polluted runoff from entering the streams and river in the Russian River watershed. The federal, state, and county regulations seem to be adequately minimizing point source agricultural pollution, and could benefit from increased riparian vegetative buffer zones to help slow the flow of polluted runoff, increase infiltration, and minimize the amount of nutrients that reach the waterways throughout the watershed. Conclusion: While this project did not result in a definitive answer as to what is causing the most nutrient pollution in the Russian River watershed, based on the findings of project, it is safe to speculate that total loads of suspended sediment, nitrogen, and phosphorus were lower throughout Sonoma County when there was less agricultural land use since the modeling data predicts higher total loads as agricultural land use increases. In addition to an increase in vineyard, the Sonoma County Crop Reports recorded a two - fold increase in the number of cattle in the county between 1990 and 2018.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Sonoma
- Department:
- Biology
- Creator:
- Sperou, Emily S.
- Description:
- Purpose of the Study: Long-lived iteroparous females may suppress reproduction during unfavorable conditions to maximize lifetime reproductive success. Capital breeders must accrue sufficient body reserves to support reproductive effort or they may exhibit reproductive failure. The basis of these reproductive decisions is not well understood. Northern elephant seals are seasonal, colonial breeders with a period of embryonic diapause and biannual foraging trips divided by a breeding and molting haul out. Being capital breeders, they use the post-breeding foraging trip to recover body mass lost during lactation and the gestational foraging trip to accumulate resources for lactation. Females exhibit high natality, roughly 15% of females skip breeding each year. A previous study suggested alteration in baseline cortisol concentrations may be the proximate mechanism linking foraging success and reproductive suppression, but evidence of an interaction between cortisol and reproductive hormones is currently lacking. Procedure: We investigated a suite of reproductive hormones (progesterone, 17β- estradiol, inhibin A, prolactin) and cortisol, to determine patterns across life-history stages. We analyzed 1,029 serum samples from 441 adult female NES during their biannual haul outs. Included in this dataset were 30 females known to have skipped breeding. Findings: The data confirmed a highly seasonal pattern to changes in sex hormones. Estradiol and inhibin were high during the late breeding haul out, suggesting the timing of ovulation. Progesterone was highest at the end of the molt, indicating implantation had occurred. Path analysis revealed strong influences of estradiol and prolactin on progesterone, indicating these three hormones are key for implantation. Individual variation suggests important regulatory roles for prolactin, inhibin, and cortisol in modulating implantation. The data suggest that some females suppress implantation under the modulation of cortisol and inhibin. Most females that skip breeding appear to implant but fail to maintain gestation. Conclusions: Failure to recover body reserves from the preceding reproductive event may inhibit implantation, but most non-breeding females fail to maintain pregnancy during the gestational foraging trip. This bet-hedging strategy is likely one component of a capital breeding life-history that buffers females against short-term changes in foraging success, but limits fitness costs to reproduction through multiple check-points for body reserves.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Sonoma
- Department:
- Biology
- Creator:
- Hudson, Daniel
- Description:
- Purpose of the Study: To understand male and female mate choice patterns affecting species and gender recognition via long distance chemical cues, this study examined the rough skin newt, Taricha granulosa, in both pond and creek habitats. Response to chemical cues of males vs. females was examined for T. granulosa, whereas the California newt (Taricha torosa), and the red-bellied newt (Taricha rivularis) were used to examine how T. granulosa would respond to heterospecific chemical cues as compared to conspecific cues in a region of the species’ ranges where all three species occur in sympatry. Methods: To simulate mate choice decisions in nature as closely as possible, we conducted behavioral experiments in the field using a Y-maze apparatus (olfactometer). All trials were run in the field using unique individuals. Data were combined across multiple years. Mate choice was analyzed using a nominal logistic regression model accounting for variation among year, researcher, Y-maze apparatus, sex, and species. Findings: T. granulosa females chose chemical cues of conspecific males significantly more than heterospecific males, whereas males showed no preference between chemical cues of conspecific and heterospecific females. In addition, T. granulosa males chose chemical cues of conspecific males over conspcific females, whereas females showed no preference between chemical cues of conspecific males and females. Conclusions: The results of this study support long-standing theoretical paradigms that males, who have less parental investment in offspring will adopt a strategy of seeking matings with females regardless of quality, whereas females, with greater levels of parental investment, will engage in a more discriminating mate choice strategy. In this case, females use chemical cues to avoid heterospecific males during breeding season encounters and reduce wasting her singular mating event on an act of hybridization. A result of this mating strategy is that reinforcement of reproductive isolation is maintained in this region of sympatric range overlap. In contrast, will mate with any female across multiple mating events, and use chemical cues to either locate females or to avoid other males (or both).
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Sonoma
- Department:
- Biology
- Creator:
- Tercero, Anthony D.
- Description:
- The perciform suborder Notothenioidae is comprised of Antarctic and sub-Antarctic fishes, several of which have lost their ability to rapidly upregulate major heat shock proteins (HSP’s) in response to thermal stress. In fact, some notothenioid species have instead adopted a pattern of expression resembling ancestrally constitutive genes. It is possible that evolution in the Southern Ocean has selected for increased expression of molecular chaperones given the denaturing effect extreme cold temperature has on proteins. The selective pressures of the sub-zero water may have also favored duplication events that bolster quantitative output of chaperones via gene dosage effects. Given that newly duplicated genes are under more relaxed selective pressures, it is plausible that gene duplication preceded alterations in the regulatory regions of the inducible HSP genes, enabling altered regulation of such highly conserved gene products. To test for evidence of these mechanisms, gene copy number of ancestrally inducible and constitutive isoforms within the major heat shock gene families were characterized via qPCR and compared for the Antarctic notothen Trematomus bernacchii, which has lost the inducible HSR, and the non-Antarctic notothen, Notothenia angustata, which has maintained an inducible HSR. Results indicate duplication of inducible isoforms within the Hsp70 and Hsp40 superfamily have occurred in the genome of T. bernacchii. The findings from this study suggest adaptive gene duplications may have played a role in maintaining increased protein folding efficiency in the sub-zero waters of the Southern Ocean and provided a mechanism for the evolution of alternative regulation of these conserved gene families.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Sonoma
- Department:
- Biology
- Creator:
- Rzucidlo, Caroline L.
- Description:
- Purpose of the study: Adipose tissue is essential to endotherms for thermal regulation and energy storage as well as functioning as an endocrine organ. Adipose derived hormones, or adipokines, regulate metabolism, energy expenditure, reproduction, and immune function in model systems but are less well studied in wildlife. Female northern elephant seals (NES) achieve high adiposity during foraging and then undergo natural prolonged fasts while breeding, lactating, and molting, resulting in large changes in adipose reserves. Procedure: We measured circulating levels of four adipokines, leptin, resistin, adiponectin, and kisspeptin-54, in 196 serum samples from female NES at the beginning and end of their breeding and molting fasts. We examined the relationships between these adipokines and life history stage, adiposity, mass, cortisol, and the immune cytokine interleukin 6 (IL-6). Findings: All four adipokines varied with life history stage. Leptin concentrations were highest during the beginning of the breeding haul-out and resistin concentrations were higher throughout the breeding haul-out compared to the molt haul-out. Adiponectin was highest during the beginning of both haul-outs and kisspeptin-54 concentrations were highest during the end of the breeding haul-out. Leptin, resistin, and adiponectin were associated with measures of body condition, either adiposity, mass, or both. Resistin, adiponectin, and kisspeptin-54 were associated with circulating cortisol concentrations. Resistin was strongly associated with circulating IL-6, a multifunctional cytokine associated with the innate immune response. Adiponectin was associated with glucose concentrations and may be a driver of tissue-specific insulin sensitivity during life history stages categorized by high adiposity. Increased cortisol concentrations late in lactation were associated with increased kisspeptin-54 which may play a role in initiation ovulation in NES. Conclusions: This study suggests dramatic changes in circulating adipokines with life history and body condition that may exert important regulatory roles in NES. Differences from biomedical model systems suggest the potential for modifications of expression and function of adipose-derived hormones in species that undergo natural changes in adiposity as part of their life-history.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Sonoma
- Department:
- Biology
- Creator:
- O’Gorman, Cory James
- Description:
- Purpose of the Study: California black oak, Quercus kelloggii, plays an important role in the lifeways of many indigenous tribes throughout California. Native peoples tend black oaks using Traditional Ecological Knowledge (TEK) to encourage the development and proliferation of specimen oaks. These mature, large, full crowned trees provide a disproportionate amount of ecosystem services, including acorns and habitat, when compared to smaller black oaks. Altered approaches to land management and the cessation of frequent low intensity cultural burns places these specimen oaks at risk from encroachment, forest densification, and catastrophic fire. Procedure: This project is a collaboration between Sonoma State University and the Native Advisory Council of Pepperwood Preserve. Data were collected from 55 specimen black oaks at Pepperwood Preserve in north east Sonoma County. Ecological variables were measured to identify abiotic and biotic drivers of growth habit, scorch height and fire fuels. A certain crown shape is desired by many of today’s traditional gatherers including those represented on the Pepperwood Native Advisory Council. Findings: Encroachment was found to have a significant negative effect on both canopy area (p=0.0027) and live crown ratio (p=0.0378). Encroachment did not affect surface and ladder fuel load accumulation since the Tubbs Fire in October 2017 (p>0.05). Neither surface and ladder fuels nor encroachment variables significantly affected scorch height on the specimen oaks (p>0.05) following the Kincade Fire. Conclusions: This work will allow for the reimplementation of TEK to nurture specific specimen black oaks at Pepperwood Preserve at the discretion of the Native Advisory Council and increase access to land and culturally significant plants by local tribal communities. This has far reaching implications on tribal peoples’ well-being, their ability to engage in cultural practices, and ecosystem health.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Sonoma
- Department:
- Biology
- Creator:
- Molinaro, Holly
- Description:
- Hamadryas baboons (Papio hamadryas) live in a complex multilevel social system with the one-male-unit (OMU) at the core. OMUs consist of an adult alpha male with one or several adult females, their dependent offspring and sometimes a few follower males. Previous research has documented that OMUs form in four distinct ways in wild populations. In December 2015, Oakland Zoo introduced two juvenile males into the hamadryas baboon exhibit. At the time of this study, these males were approaching sexual maturity. The complex social structure of this species and the changing social dynamics that might result as they reach sexual maturity provide a unique opportunity to utilize social network analysis (SNA) methods to examine OMU formation in a captive setting with an eye towards potential management strategies. SNA is a visualization method of looking at social data that allows researchers to understand sociality in terms of the importance of each individual, any subgroups, as well as the larger overall group dynamic. Behavioral and proximity data were collected over a six-month period (July- Dec 2019). These data were then transformed into networks to analyze the two now subadult males’ behavior over time and the presence of any subgroups. I found that one of the subadult males formed his first OMU following one of the four pathways found in wild studies. Despite changing group dynamics, overall group cohesion remained unchanged. This study reveals hamadryas OMU formation patterns in captivity as well as suggests potential welfare management issues that might arise.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Sonoma
- Department:
- Biology
22. Interactions among Sudden Oak Death, Fire Fuel Loads, and Climate in Sonoma County Oak Woodlands
- Creator:
- Hernandez, Manuel
- Description:
- Purpose of the Study: Understanding impacts of invasive pathogens and wildfire on forests is a major challenge facing scientists, land managers, and policymakers. In this study, I used a long-term plot network in eastern Sonoma County to disentangle the interactions among an exotic pathogen (Phytophthora ramorum), fire fuels loads and climate in oak woodlands. I investigated the interactions among: 1) sudden oak death (SOD) inoculum loads, disease prevalence and pre-fire surface and ladder fuel loads, 2) surface and ladder fuel loads and canopy condition, and 3) canopy condition and post-fire surface and ladder fuel loads. Procedure: From 2004-2016, measurements of disease prevalence, tree growth, tree mortality and tree survival were collected for the three most abundant SOD host tree species: coast live oak (Quercus agrifolia), California black oak (Quercus kelloggii), and California bay laurel (Umbellularia californica). In 2014, surface fire fuel loads were quantified, and airborne Lidar data were collected. Elevation, slope, average potential solar insolation, and topographic moisture index, and climate water deficit were also calculated for these plots to determine the interactions of microclimate and topography on pre-fire fuel loads. In 2019, I recorded tree mortality and survival of these same species and quantified surface and ladder fuel loads across 33 plots (15 x 15 m) with a range of burn severity following the 2017 LNU Complex Fires. To analyze the interactions among abiotic and biotic factors over time I created a hypothesized pathway to describe potential direct and indirect effects of oak mortality, disease load, microclimate, topography, climatic water deficit, pre-fire fuel loads, and canopy condition on post-fire fuel loads. I tested this pathway using a path analysis. Findings: I found that P. ramorum disease load had no effects on pre-fire fuel loading. However, oak mortality in 2014, indirectly affected by P. ramorum disease load, significantly increased the amount of large surface fuels, and decreased ladder fuels. Plot elevation and maximum temperature also had a positive correlation with pre-fire ladder fuel amounts. Pre-fire ladder fuels, in concert with drought intensity and slope interacted to effect canopy condition post-fire (in particular, percent canopy damage). Percent canopy damage was greater in less sloped plots with greater amounts of ladder fuels and increased drought severity. Pre-fire ladder fuels also had a significant direct effect on post-fire ladder fuels, whereas increased amounts of post-fire ladder fuels were observed in less-sloped plots with greater amounts of pre-fire ladder fuels and more percent canopy damage. Surprisingly, plots with increased fire severity due to increased fuels had increased re-sprouts and re-growth of U. californica trees immediately following fire. Conclusions: Current management practices in oak-woodlands include the removal of U. californica in the presence of oaks to reduce the potential P. ramorum inoculum load. My results support this practice, as SOD indirectly increases fire fuel loads, which may in turn increase both the future susceptibility of the ecosystem to fire and the severity of these future wildfires.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Sonoma
- Department:
- Biology
- Creator:
- Ghavamian, Yasmeen
- Description:
- All zoos grapple with challenges of keeping captive animals engaged in natural behaviors, especially for bears which prove to be among the more challenging species to keep stimulated. In captivity, a common indicator of poor welfare is the presence of stereotypic behaviors. In this study, we test whether providing increasingly complex feeding enrichment decreases the duration of stereotypic behavior and increases enrichment interaction for three adult female sun bears (Helarctos malayanus) at Oakland Zoo in California. We compared the effects of two different feeding enrichment devices- presented to the bears at three complexity levels- on sun bear stereotypic behavior. After three weeks of baseline data collection when no complex enrichment was present, we introduced the complex enrichment three times a week per level over six weeks. In addition, we measured each bear’s interaction with the enrichment devices to examine the effect of complexity on enrichment use. Providing increasingly complex enrichment decreased the duration of stereotypic behavior when compared to the baseline phase. Across the six weeks, the duration of stereotypic behavior was significantly less on the complex enrichment days compared to the days when complex enrichment was absent. Increasing enrichment complexity had variable effects on enrichment use. Our results indicate that providing complex enrichment decreased the duration of stereotypic behaviors, however, the effects of complex enrichment did not carry over on the days when the enrichment was no longer present. These results suggest that providing increasingly complex enrichment may have a positive influence on the behavior of captive bears.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Sonoma
- Department:
- Biology
- Creator:
- Chen, Sylvia
- Description:
- Worldwide, there are 65 million people that have epilepsy and approximately 200,000 additional individuals are diagnosed with epilepsy annually. There is no cure and currently available anticonvulsants, which are medications to treat seizures, are not universally effective. Additional studies are needed to generate better treatment options. Drosophila melanogaster provides a valuable and efficient model to study seizure disorders due to the low cost of maintenance, genetic tractability, and short lifespan, which allows for observation at various life stages. D. melanogaster also possesses similarities to humans on cellular and subcellular levels. These advantages allow the development of a model for the high throughput study of epilepsy. This study aims to induce single and multiple seizures and monitor locomotion, learning, and memory. The results from the negative geotaxis assay, which takes advantage of D. melanogaster’s innate climbing behavior, suggest that single seizure events have minimal impact, whereas multiple seizures result in deficits in visuo-motor/motor behavior. Additionally, a visual place learning assay was used to study the cognitive abilities and results suggest a single seizure event impacts learning and memory. Lastly, whole brain slides were made and determined lesions in brain tissue result from repeated seizure events. The significant findings from this research may contribute to improve therapeutics for epilepsy by providing a method of high throughput screening.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Fresno
- Department:
- Biology
- Creator:
- Gonzalez, Dalia Banesa
- Description:
- This study involved Drosophila melanogaster, the common fruit fly, as the model organism to study the behavioral differences seen in flies overexpressing the human tau protein throughout their adult life span. The tau protein (MAPT – microtubule associated protein tau) is linked to Alzheimer’s Disease (AD). It is seen in both humans and Drosophila and has been noted to decrease learning and cognitive abilities in both. This study aimed to look at the cognitive and behavioral difference seen as adult flies age. The adult flies were tested at three different ages (young, middle, elderly) in order to look for any progression declines in behavior as the flies aged and expressed the human tau for longer periods of time. The human tau was driven into two different areas of the brain (ellipsoid body, mushroom body) that have been shown to be important regions for learning and memory in insects. The flies were tested in two different behavioral assays, a visual place learning assay and a negative geotaxis assay, in order to quantify spatial learning and memory. Additionally, fluorescence microscopy was used to analyze the amount of tau present in the brain at different times of the adult’s life, which confirmed the increased expression of tau as flies aged. As tau-expressing flies aged, both visual place learning and memory were impacted. These flies also showed a decline in planning ability. The behavioral declines seen in this study can be correlated to patients with AD who also overexpress this abnormal tau protein. This study aims to create a better Drosophila melanogaster model for AD. Moreover, the findings of this study can contribute to a better model organism for AD, which allow us to test interventions prior to the onset of dementia.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Fresno
- Department:
- Biology
- Creator:
- Montiel, Christian M.
- Description:
- The Escherichia coli cAMP receptor protein (CRP) requires both DNA binding and RNA polymerase recruitment for its transcriptional activation function. The DNA recognition of CRP is performed by the F-helix (residues 180-185) and several F-helix residues (Arg180, Glu181, Gly184, Arg185) are well-characterized as to their importance in DNA binding. However, no apparent function has been known for the other two residues (Thr182 and Val183). In this work, I show that the position-183 amino acid (Val 183) is important for the transcriptional activity of CRP. First, Ala substitution at position 183 led to an increase in transcriptional activation activity. Second, CRP mutants altered at position 183 were created to show an inverse correlation between amino acid size and transcriptional activation activity (V183A > V183G > wild type CRP > V183I > V183M > V183F = no activity). Third, the loss of the activity in V183F could be restored by a smaller amino acid substitution (IleGly) at position 172, implying that it is the combined size of positions 172 and 183 which is important. A structural analysis of CRP reveals that the position-183 amino acid faces the opposite of target DNA and is in close proximity to the position-172 amino acid. The requirement of a small residue at position 183 is hypothesized to avoid steric hindrance to the position-172 residue as steric hindrance would misalign the nearby AR1 residues, leading to poor RNA polymerase recruitment and transcriptional activation.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Fresno
- Department:
- Biology
- Creator:
- Thomas, Jason Michael
- Description:
- Bacteria must be able to withstand a myriad of stresses from both their environment, and in the case of pathogens, from their host. Low molecular weight thiols serve as redox buffers to maintain a reducing environment in the cell and participate in various protective mechanisms, including detoxification of reactive oxygen and nitrogen species, resistance against electrophiles and antibiotics, and protection against environmental stressors. In this study, I analyze the transcriptome of two heterotrophic clinically relevant bacteria, Pseudomonas aeruginosa PAO1 and Staphylococcus aureus SAUSA300 and transposon mutants disrupted in thiol biosynthesis. The transposon mutants are disrupted in P. aeruginosa glutathione biosynthesis gene, gshA, and S. aureus bacillithiol biosynthesis gene, bshC. I also analyze the transcriptome of the autotrophic cyanobacterium, Synechocystis PCC 6803 as well as a knock-out mutant disrupted in egtB, which is involved in ergothioneine biosynthesis. P. aeruginosa gshA mutant is downregulated in type II and type VI secretion systems and upregulated in type III secretion systems while the S. aureus bshA mutant is downregulated in type VII secretion suggesting that thiols play a role in secretion of effectors. Strikingly, both P. aeruginosa and S. aureus switch to anerobic respiration with nitrate as the electron acceptor in the thiol mutants. A number of other virulence factors are also differentially expressed in these mutants agreeing with the attenuation of the mutants in disease models. In contrast, genes related to high light resistance, acid stress tolerance, and osmotic stress tolerance are downregulated in Synechocystis PCC 6803. This suggests that ergothioneine is involved in abiotic stress tolerance in the autotrophic bacteria. Overall, we demonstrate that LMW thiols are involved in a myriad of functions have not been previously identified.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Fresno
- Department:
- Biology
- Creator:
- Ajanel Gomez, Jehiel Abigail
- Description:
- Discovered in 2004, tunneling nanotubes (TNTs) are actin-based, bridge-like structures that allow the intercellular transport of cellular components, electrical signals, and pathogens. Thus, TNTs have been implicated in viral propagation, neurodegenerative diseases, and cancer. Most research has focused on examining the molecules within cells that aid in TNT formation and function, but little has been documented on the role that exogenous molecules have in TNT formation. Past research has determined that hydrogen peroxide (H2O2) induces TNTs in various cell lines; however, the amount of H2O2 used was above was high (100μM). The aim of this study was to establish if TNT formation can be induced by pathophysiological H2O2 concentrations. In addition, we also investigated glutamate, an inducer of actin-based filopodia in astrocytes, as a possible TNT inducer. The data obtained using fluorescence microcopy suggest that low concentrations of H2O2 and glutamate are able to increase TNTs in both HeLa and CAD cell lines. Furthermore, cells treated with low concentrations of H2O2 or glutamate showed an increase in the expression of Myo10, a protein that has been linked to TNT formation and function. Lastly, the data obtained with a microscope capillary single cell sorting system suggest that H2O2 and glutamate can induce the formation as well as the elongation of cellular protrusions in distances ranging from 14-96 μm. Altogether, these results provide useful insights regarding TNT formation pathways in cells as well as the exogenous molecules involved in the formation of TNTs.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Fresno
- Department:
- Biology
- Creator:
- Surber, Lisa L.
- Description:
- Research on animal movement patterns and factors that influence these patterns is vital to conservation of endangered species. The California Red-legged frog (Rana draytonii) is a threatened species native to California. Their rapid decline has been largely attributed to habitat loss and introduction of invasive species, including the American Bullfrog (Lithobates catesbeianus). The aim of this research was to compare the nocturnal habitat use and seasonal movement patterns of R. draytonii and L. catesbeianus. I conducted a radio telemetry study in Sonoma County, California and mapped the locations of 13 L. catesbeianus and 51 R. draytonii from May 2017 to June 2018. Using a mixed model, I evaluated the effects of species, sex, size and rainfall on frog movement rate and compared habitat use relative to a water source. Within this model species, size and sex were found to have significant effects on movement rate. Rainfall was not found to have a significant effect on movement rate for either species. When comparing nocturnal habitat movement, I found that in the summer months species occupy different places relative to water sources in a creek environment; R. draytonii position themselves higher and further away from the nearest open water than L. catesbeianus. My work suggests that there are significant differences between the seasonal movement patterns and nocturnal habitat use of native R. draytonii and invasive L. catesbeianus. These differences may be helpful to conservation practices facilitating the survival of threatened R. draytonii.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Sonoma
- Department:
- Biology
- Creator:
- Trujillo, Andreina
- Description:
- Tunneling nanotubes (TNTs) have been recently discovered as an essential form of cell-cell communication in multicellular organisms. Although TNTs appear to be an important cell-cell signaling pathway, its mechanism of formation and functions are still not fully understood. A central issue is determining whether mitochondria play a vital role in the formation of TNTs. Previous studies have shown that exposure to a low concentration of ethidium bromide (EtBr) in mammalian cells caused a complete loss of mitochondrial DNA (mtDNA) leading to non-functional mitochondria (Rho0 cells); therefore, this technique will be applied to produce a HeLa Rho0 cell line to study the effects of non-functional mitochondria on TNT. Here we will determine if Rho0 cells were successfully engineered by labeling the mtDNA with Quant-it PicoGreen Reagent and labeling of the plasma membrane with WGA Rhodamine to determine the effects on TNT formation. We will also determine the expression levels of Myosin-X (Myo10), a known TNT inducer, in Rho0 cells versus control cells. Overall results revealed that mitochondria do play a role in TNT formation. As cells were in the process of becoming Rho0 cells, TNT formation increased peaking at week 4. As Rho0 cells stabilized, TNT formation significantly decreased. In addition, cells were seen to expel their mitochondria into the extracellular medium in week 6, a process known as mitochondrial extrusion. Lastly, Myo10 protein levels significantly increased during the production of a stable Rho0 cell line at week 4. The increase in Myo10 protein levels correlated with an increase in TNT formation.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Fresno
- Department:
- Biology
- Creator:
- Parker, Jeffrey Thomas
- Description:
- The purpose of this study is to compare the genetic distances of Mimetus hesperus and Theridion neomexicanum within and between the San Joaquin Valley and Mojave Valley regions. To my best knowledge this is the first genetic study of M. hesperus. Mountains and distance are well known barriers to gene flow in species with lower vagility. For short lived spiders, the only non-synanthropic transport method over mountains is ballooning. Ballooning spiders rely on surface area for lift, and larger spiders have a difficult time sustaining flight as they have less surface area per unit weight. M. hesperus hunts other spiders and probably has large spiderlings which make it difficult to balloon from hatching. With insufficient ballooning the Sierra Nevada Mountains should act as a barrier to gene flow for M. hesperus. I predict that comparisons between populations of M. hesperus on the same side of the Sierra Nevada Mountains will show smaller genetic distances than comparisons between populations on opposite sides of the mountains. M. hesperus and T. neomexicanum were collected from sites around the Sierra Nevada Noubtains and either died of natural causes or were humanely euthanized in <0°C ethanol. DNA was extracted and PCR was run to amplify the cytochrome oxidase 1 sununit c gene. Amplified sequences were run in two percent agaorse gel to look for banding of appropriate length and gels showing target band were purified and sent to the University of Florida for sequencing. All other bands were heavily troubleshooted and re amplified Sequence chromatograms were analyzed to ensure only pure sequences were used in analysis. Insufficient numbers of T. neomexicanum were resolved so they were used as outgroups in analyzing M. hesperus. Sequences were aligned using clustalW and cut in MEGA to ensure accurate comparisons. Pairwise distances were calculated between all specimens. A neighbor joining tree was calculated, and overall percent divergence based on collection sites, and tree groupings was computed. Character based maximum parsimony and maximum likelihood trees were calculated to confirm results seen in neighbor joining analysis. Haplotype diversity was shown by grouping all single nucleotide polymorphisms for comparison of haplotypes and by collection site and tree groupings. Genetic distance and trees reveal three distinct groupings of M. hesperus, but a permutation test found distance within populatioins from both sides insignificant, so all specimens were grouped as either east or west of the mountains. Although anecdotal at best, haplotype diversity hints that M. hesperus may have brached from the west to the east. The Sierra Nevada Mountains appear to separate populations of M. hesperus in the Central Valley and in the Mojave more than distance alone. M. hesperus populations collected over 100 miles apart on the west side of the mountains showed no significant divergence, indicating some unknown mechanism of gene flow linking these populations, but a larger sample size is needed to confirm this.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Bakersfield
- Department:
- Biology
- Creator:
- Hult, Susan Marie
- Description:
- The Blainville's Horned Lizard (Phrynosoma blainvillii) is endemic to California and ranges from northern California (Butte County), to the northwestern tip of Baja California in the southern part of its range, west of the Sierra Nevada Mountains and the southern California deserts in the eastern part of its range, and along the Pacific coast from northern Baja California to Monterey, California in the western part of its range. Phrynosoma blainvillii is listed as a California Species of Special Concern and a Bureau of Land Management (BLM) Sensitive Species. Human activities have been primarily responsible for declines in populations. There has been few field research studies published on the general ecology of P. blainvillii, particularly in the San Joaquin Valley. I initiated a radio-telemetry study to collect data on home range size and habitat use at two sites (Atwell Island and Semitropic Ridge Preserve) in the southern San Joaquin Valley, California. I calculated home range size from 10 lizards, five at each site. Using the 100% Minimum Convex Polygon (MCP) estimator I found home range sizes were between 0.58 ha to 13.93 ha, with an average size of 4.98 ha (± 1.54). When above ground and active, P. blainvillii at either site used areas of bare ground more often than expected based on equal use. At the Semitropic site, the lizards used areas under shrubs almost as often as bare ground, while at the Atwell site the lizards used areas of sparse vegetation more often than expected, but not as much as bare ground. Lizards at both sites used medium-dense and dense areas of vegetation much less than expected based on equal use. In adult P. blainvillii, we recorded a moderately skewed sex ratio of more males than females, but in young P. blainvillii, there were more females than males. Average snout-vent length (SVL) of females was 72.31 mm and for males 68.81 mm. The adult horned lizards were most active in April and May while young horned lizards were most active in August and September. In the spring, the morning activity hours peaked at 0900–1100, in summer, it was 0900–1000, and in fall, it was 0900–1300. All age classes of P. blainvillii were most often above ground and active at surface temperatures of 28–34°C. The presence of alkali flats and sandy soil correlated with a high abundance of horned lizards, and within our two study locations, they revealed a distinct preference for Sandridge loamy fine sand over other available soil types. The lizards used kangaroo rat burrows rather than shrubs for heat refugia but used shrubs frequently as an escape from predators. Food items found in scats were predominantly ants, but beetles and other arthropods were also found in large numbers.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Bakersfield
- Department:
- Biology
- Creator:
- Jones, Maureen Gertrude
- Description:
- In most temperate coniferous forests, the vast majority of vascular plant species richness can be found in the understory layer. While the large-scale conversion of forests to plantations has made it increasingly important to understand how understory flora responds to timber harvesting, there is a surprising paucity of data concerning this topic. Ideally, long-term studies using permanent plots would be used to directly assess post-logging patterns of recovery, both for whole floras and for individual species of conservation interest. Unfortunately, these studies are lacking, and alternative approaches are critical. I used a 420 year forest chronosequence to assess the relationship between stand age, overstory cover and vascular plant understory richness and composition in one watershed in the Siskiyou Mountains of Oregon. The chronosequence consisted of six young managed (age 7-44) and nine older unmanaged (age 90-427) stands. All stands were similar in underlying geology, slope, elevation, and aspect. I found a non-linear relationship between stand age and richness, in which richness showed a steady decline as young stands entered canopy closure, then increased as stands gained older forest attributes such as light gaps and structural diversity. I also found that percent open canopy was correlated with total percent understory cover, richness, diversity and changes in species composition. In general, young stands were characterized by high shrub and graminoid cover and old stands were characterized by an abundant herb layer. In my study area, a large proportion of young managed stands are currently entering canopy closure, a stage characterized by low vascular plant species richness and abundance. I use my results to discuss the potential effects of past and future forest management on vascular plant understory species.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Humboldt
- Department:
- Biology
- Creator:
- Chand, Shristi
- Description:
- Bacterial second messenger, c-di-GMP, regulates important functions such as biofilm formation, motility, and virulence. C-di-GMP also has an immunostimulatory property, so can be used as a vaccine adjuvant. In this project, DgcZ (a diguanylate cyclase) was engineered to create hyperactive mutants in c-di-GMP production. For this, two protein sites were targeted: substrate (GTP) binding site and product (c-di-GMP) inhibition site. At the GTP binding site, three residues (L134, D182 and R204) were tested through codon randomization and in vivo c-di-GMP production assay, but none of the positions provided high activity DgcZ mutants superior to wild type DgcZ. In contrast, the engineering at the product inhibition site was fruitful as superior mutants could be made at both R197 and E200 positions. So far, R197T, E200A and E200G were identified to be better than wild type DgcZ in in vivo c-di-GMP production based on both Clp toxicity-masking assay and c-di-GMP toxicity assay. These mutants were toxic to the host cell when highly produced. The toxicity problem was circumvented by tagging one of the mutants (E200A) with PelB, a signal sequence to the periplasmic space, at the N- terminus and the fused PelB-E200A was not toxic to the cells. In the future, the resultant PelB-E200A needs to be tested thoroughly through protein expression, purification and in vitro c-di-GMP production assay for mass production of c-di-GMP.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Fresno
- Department:
- Biology
- Creator:
- McGrew, Karen C.
- Description:
- Russian Peak, at an elevation of 8200 feet, is situated in the Salmon Mountains, a north-south trending range centrally located within the Klamath Region of northwestern California. The Salmon Mountains are drained by the Scott River on the east and by the Salmon River on the west; both rivers course northwesterly to discharge into the Klamath River. The Klamath Region is a geologically old and structurally complex series of ranges which grade into the Coast Ranges on the west and into the Cascade Mountains on the northeast. Russian Peak is located in Klamath National Forest, within Siskiyou County, approximately eight miles westsouthwest of the town of Callahan. Access to the area is via Forest Service roads and·unimproved roads off of State Highway 3, which runs northward out of Weaverville. Selection of Russian Peak and its environs as a study area was based on several factors: the lack of bryological collections in the area (Personal communication, Norris, 1973); the presence of relict conifer species as described by Sawyer and Thornburgh (1971); and the presence of a diverse, largely circumboreal moss population on the Marble Mountains, located approximately fifteen miles to the northwest (Spjut, 1971). The objective of the following study was to identify bryophyte species within the area and to determine if the findings would lend further support to the concept of a refugium or "central" area, as described by Whittaker(l961), within the Klamath Region. Collections were made from around five lakes, including their headwaters and drainages, during the summers of 1973 and 1974. A total of 786 specimens were collected, representing 152 species. Collections were made at elevations between 5500 feet and 7200 feet in the following drainages: 1) Sugar Lake and Sugar Creek, August, 1973; 2) South Sugar Lake, August, 1974 (with D.H. Norris); 3) Bingham Lake, September, 1974 (with D.H. Norris); 4) Russian Lake, September, 1973; 5) Waterdog Lake, Lower Russian Lake and South Russian Creek, September, 1973. Bryophytes were collected along paths, in drainages, and from around the lakes. Effort was made to include special habitats, such as springs, marshes, serpentine outcrops, exposed granite walls, rock crevices, and areas adjacent to perennial snow patches. Each collection was identified, checked with specimens from the cryptogamic collection at Humboldt State University, and verified by D. H. Norris. Voucher specimens are on deposit at the Humboldt State University Herbarium (HSC). Collection numbers preceded by the prefix "N" are those of D. H. Norris; all others are those of the author.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Humboldt
- Department:
- Biology
- Creator:
- Ziser, Brian.
- Description:
- Clearcut logging of numerous small stands of trees over the last fifteen years has provided suitable areas for the study of early secondary plant succession on the western slope of the central Sierra Nevada mountains. Familiarity with early successional patterns in these areas is essential in the development of appropriate silvicultural practices for the maintenance of viable, productive forests, as well as aiding in effective management of wildlife resources. Clearcut logging has been widely practiced and researched in the coastal Redwood forests of Northern California, and in the Douglas Fir dominated forests of Oregon and Washington. However, as indicated by the available literature, no significant research on secondary succession following clearcutting has been conducted in the Sierra Nevada mountains. This project was undertaken to provide information about early regrowth patterns on these clearcut areas.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Fresno
- Department:
- Biology
- Creator:
- Yoshimura, Glenn.
- Description:
- Six species of Simulium larvae found in the Kings River near Piedra, Fresno County, California, are described. The black fly larvae and pupae were reared in the laboratory for taxonomic association of the immature instars, the pupae and the adults. The differential morphology of S. argus Williston, S . aureum Fries, S. canadense Hearle, S. virgatum Coquillett, and S. vittatum Zetterstedt is presented in greater detail than ever before, with the S. arcticum Malloch larva being described for the first time.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Fresno
- Department:
- Biology
- Creator:
- Willson, Ruth.
- Description:
- Nitidulid beetles have been recognized as major pests of figs In California since 1900 (Simmons et al., 1931). Early workers were concerned primarily with Carpophllus hemlpterus (Linnaeus), the dried-fruit beetle, as the principal nitidulid pest (Smith et al., I927). More recent studies have shown four other pestiferous nitidulids: Carpophllus freemanl Dobson, Carpophllus mutllatus Erichson, Urophorus humeralls (Fabrlcius), the pineapple beetle, and Haptoncus luteolus Erichson. Of these species, C. mutllatus was found in 56^ the Calimyrna figs in one sample from Madera County, California (Smilanick and Ehler, 1975)*
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Fresno
- Department:
- Biology
- Creator:
- Warner, Donald Remi.
- Description:
- The natural history of the Fresno kangaroo rat, Dipodomys nitratoides exilis, in the San Joaquin Valley's alkali sink habitat was first described by Culbertson (1946). His study included little information on the interspecific interactions with other rodent species or the intraspecific interactions of the Fresno kangaroo rat. Little attention has been given to its ecology since. Instead the emphasis has been placed on the controversy of whether there do or do not exist three distinct subspecies of Dipodomys nitratoides.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Fresno
- Department:
- Biology
- Creator:
- Stewart, Katherine.
- Description:
- The California State Park system, hereafter referred to as CalDPR, has sought for five years to include Carmel Bay, California, in its park system as an underwater park. Carmel Bay is approximately 15 km (5 mi ) in area, located between Pescadero Point, 36°33'40"N by 121°56130"W, and Carmel Point (Point Lobos) at 35°33'40"N by 121°55'42"W, immediately south of the Monterey Peninsula (Fig. 1). It is about 125 km (80 mi.) south of the city of San Francisco, and is a popular weekend trip for visitors from the Bay Area and inland cities such as Sacramento and Fresno. Since the advent of recreational diving in the 1950's, divers have found that the subtidal scenery here is equally as beautiful as the world-famous beauties of its shoreline.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Fresno
- Department:
- Biology
- Creator:
- Shumaker, Evelyn.
- Description:
- An important aspect of any group of organisms from both ecologic and evolutionary points of view is the part played by that group in channeling the flow of energy within the community in which it lives. Foraminifera, marine protozoans with calcium carbonate or sand grain (agglutinated) tests, are recorded as feeding chiefly upon bacteria, small diatoms, and nannoplankton in a wide variety of marine environments (Myers, 1943; Bradshaw, 1961; Lee et al., 1966; Muller and Lee, 1969; Murray, 1963). Myers (1943) found the diet of foraminifera includes soft-bodied flagellated organisms such as gametes of larger algae as well as filamentous algae, minute eggs, spores, and cysts. Their food items are usually below 25 y in size (Lipps and Valentine, 1970). Predators upon foraminifera range from highly specialized microcarnivores that feed largely on foraminifera to less selective ones that include foraminifera in a mixed diet and to generalized feeders that ingest foraminifera along with much other material (Lacaze-Duthiers, 1856; Mare, 1942; Graham, 1955; Morton, 1958; Lipps and Valentine, 1970). The present study considers the effect of organic enrichment on the abundance and diversity of intertidal benthic foraminifera. This requires an understanding of regional differences in their habitat and local variations of rnicroenvironments within that habitat. Sediment is an important microhabitat feature and must be included in a complete study of foraminifera! assemblages.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Fresno
- Department:
- Biology
- Creator:
- Ruagh, Amer Ali.
- Description:
- The primary purpose of this study was to-investigate the feeding habits of silversides (Family Atherinidae) in Elkhorn Slough, Monterey Bay, California, since little detailed work on the feeding habits of silversides from California has been published.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Fresno
- Department:
- Biology
- Creator:
- Moss, Martin.
- Description:
- The field of membrane investigation is over 80 years old. Yet that remarkably complex and diverse structure, the cell membrane, continues to elude precise definition of structure and function. Observers have found cell membranes to be involved in a variety of functions essential to cell survival, such as preservation of cell boundaries, regulation of passage of ions and other molecules into and out of the cell, modification of intercellular interaction, and regulation of release of cell products.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Fresno
- Department:
- Biology
- Creator:
- Mahoney, John.
- Description:
- The rate of growth of catfish farming in the United States during the past 16 years is. unequalled in the history of fish culture. Commercial production of channel catfish (Ictalurus punctatus) has increased from its beginnings in 1960 to an estimated 36,000,000 pounds in 1968, it now exceeds the total production of all other commercially reared fish species in the United States. (Fijan, et. al., 1970) .
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Fresno
- Department:
- Biology
- Creator:
- Lynch, Michael Wayne.
- Description:
- The presence or absence of intestinal parasites in a human population is one indication of the quality of life the people lead. Particularly, human intestinal helminths and protozoans have been used to indicate the sanitary standards of a population. Arnett, Wenrich, and Stabler (1933) reported on a survey for intestinal protozoans in 401 college freshmen in the eastern United States. They found 33.1% had one or more species of protozoans after analyzing one stool sample from each subject. McQuay found 20.1% protozoan and 20.2% helminth infections in 4,000 individuals drawn from furloughed missionary families from tropical and subtropical countries (McQuay, 1967). Gleason et al. reported on a stool survey of about half the permanent residents of Aspen, Colorado, done after an outbreak of giardiasis during the 1965-66 ski season (Gleason et al., 1970). Of the 419 people sampled, 5%. were positive for Giardia lamblla. All other protozoans were found in less than 2% of the subjects. The only helminth found was one case of Enterobius vermicularis. The outbreak was attributed to the contamination of water supplies with sewage. In 1971 Allen and Ridley reported on a survey for parasitic infections in patients of a British hospital who had once resided in tropical or subtropical areas (Allen and Ridley, 1971). In this study of 1,000 people, 33.3% were found to have pathogenic or potentially pathogenic helminths or protozoans. An additional 15.1% of the subjects were infected with commensals living in the digestive tract or elsewhere in the body. The present study was a survey for human intestinal parasites in Cantua Creek, a farm labor community 60 miles southwest of Fresno, California (Figure 1). It had a population of approximately 1,800 people, primarily Mexican Americans, Punjabis, and Caucasians. The only unifying force bringing the widely distributed labor camps into a community was the Cantua Creek Elementary School. There were several purposes for surveying Cantua Creek. The first was to determine what parasites the people had. The second was to determine if parasite transmission was occurring. The final purpose was to correlate demographic information on each subject with the presence of parasites.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Fresno
- Department:
- Biology
- Creator:
- Lam, Christine.
- Description:
- Shortly after the discovery of the role of bacteria as the etiological agents of human disease, the search for bacterial toxins began. Bacterial toxins were an important discovery, because they may enhance the pathogenicity of infection; the effect of toxins on pathogenicity depends upon the infecting microorganism, the dose, and the route of injection, as well as the interval between the administration of the toxin and the initiation of infection.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Fresno
- Department:
- Biology
47. Fawn production, habitat use, and growth in the North Kings deer herd, Fresno County, California.
- Creator:
- Holl, Stephen.
- Description:
- Previous work on the North Kings deer herd has shown that the reproductive potential of the does was high; however, there was a 50 percent neonatal loss of fawns. The neonatal loss was hypothesized to be the result of a nutritional stress experienced by the does during the spring migration, sufficient to retard fetal growth and development. A second loss of 50 percent of the remaining fawns was seen in 1971 and 1972, which appeared to coincide with the fall migration. Additional observations by Cal ifornia Department of Fish and Game personnel indicated that there were specific habitat requirements associated with the successful rearing of fawns. The present study was designed to refine the relationship between fetal growth and doe physical condition, quantitatively describe areas associated with successful fawning, and determine the physical condition, growth rates, and food habits of fawns prior to and following the fall migration
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Fresno
- Department:
- Biology
- Creator:
- Harp, Thomas Kring.
- Description:
- Ranch ponds are numerous in the foothills of the western Sierra Nevada. An article appearing in the California Cattleman (anon, 1975) estimated that there were more than 50,000 ponds of less than 0.0123 cubic hectometers (10 acre feet) in California. Nearly 40 ponds in Madera County were visited and fewer than one half were less than 0.0123 cubic hectometers. This small sample indicates that there are probably many more than 50,000 ponds in California. Most of these ponds were built to provide water for livestock or irrigation. Many ponds are stocked with fish and are a potentially valuable fishery. Currently, there is very little information available on the biology of fish in California ranch ponds.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Fresno
- Department:
- Biology
- Creator:
- George, Nelda Lee.
- Description:
- Two hemipterans, Oncopeltus fasciatus Dallas (Lygaeidae) and Leptocoris trivittatus Say (Corizidae) (Feir, 1974; Woolley, 1949), have been used extensively in research and teaching due to availability and/or ease of rearing. The common squash bug, Anasa tristis De Geer, should be added to the list since it is easily reared in the laboratory, is larger in size than either of the above, and the internal organs are brightly and differently colored permitting color coding. Additional advantages are the plant and fruit feeding habit of this species as opposed to the strictly seed feeding O. fasciatus, and the fact that it belongs to another family (Coreidae). The first steps in establishing the squash bug as a laboratory animal are the development of rearing methods, the collation of current knowledge, and the preparation of an available anatomical study. This paper describes the gross anatomy of the majority of the internal non-skeletal organ systems of the squash bug A. tristis De G.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Fresno
- Department:
- Biology
- Creator:
- Westall, Tory Lynn
- Description:
- The San Joaquin kit fox (Vulpes macrotis mutica) is an endangered species endemic to the San Joaquin Desert in the Central Valley of California. Much of the habitat in the San Joaquin Desert has been converted for agricultural, industrial, and urban development. The remaining San Joaquin kit foxes exist as a meta-population in several satellite populations and three core areas, the Panoche Valley, the Carrizo Plain, and western Kern County. Another substantial population that could be considered a core area is the urban population that is living in the City of Bakersfield. This population is fairly large and critical in contributing to the conservation of the species as a whole. The urban population of San Joaquin kit foxes has higher survival rates, lower dispersal potential, and higher reproductive success as well as increased incidence of philopatric young and larger family groups when compared to populations living in natural areas. The San Joaquin kit fox is a socially monogamous species, but philopatric young have been classified as Helpers because they assist in rearing future litters. Understanding how the altered ecosystem in the urban environment can affect reproductive traits of an endangered species is important for conservation. In this study I investigated the relative contributions of adult group members to pup rearing in urban San Joaquin kit foxes. My objectives were to quantify the relative time contributions of each individual, the different tasks performed by each individual, and the changes in time contributions and tasks performed by each individual as the pups aged. To quantify den attendance and behavior, I used proximity logging collars and base stations at each natal den, performed direct observations of behaviors, and set up remote camera stations at dens. I also compared these methods for efficiency in detecting behaviors. To determine role, I used behaviors and genetic analyses to classify each individual to one of three categories: Mother, Father, or Helper. To monitor changes in behavior as pups aged, I split the breeding season into three periods: Preparturition, Nursing, and Weaned. I monitored six groups at four locations in Bakersfield, California and had four groups that successfully reproduced and were consistently monitored. I found that proximity logging collars were unreliable in measuring den attendance of kit foxes. Cameras were an effective method for documenting behaviors, but they significantly underestimated the amount of time that foxes spent at the den. Direct observations were the most accurate method of gathering behavioral data and were used for analyses of parental care. I found that Mothers play a critical role in pup rearing. Mothers spend significantly more time at the den than either Fathers or Helpers. While Fathers spend most of their time away from the den, they provision the same amount of food as Mothers, whereas Helpers provisioned significantly less than either Mothers or Fathers. Mothers primarily groomed young, provisioned, guarded while young played, and performed den defense. Fathers primarily provisioned and provided den defense. Helpers mostly interacted with the pups through play, which may teach the pups the social hierarchy and establish dominance. While Helpers do not provide direct care to young, they may provide a form of insurance of parental care of young should something happen to either of the parents. Helpers are likely tolerated within their natal range because there is an increased abundance of food within the urban environment and their presence is not detrimental to the success of the current litter. I also documented two incidences of social polygyny and genetic polyandry over the course of my study. This is likely tied to the super abundance of resources because more plentiful resources result in a decreased need for paternal care and so one male can split his time between multiple litters. My results indicate that there is a decreased need for assistance in pup rearing in the urban environment due to the increased resources available. Helpers do not actually help in rearing pups and Fathers are not as necessary to successful pup rearing. Mothers play an essential role in pup rearing and are necessary for successful reproduction in the urban environment.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Bakersfield
- Department:
- Biology
- Creator:
- Clymore, Gary Lee.
- Description:
- Waters containing enteropathogenic microorganisms (i.e., Salmonella, Shigella) are considered unsafe for human consumption. Traditionally, indicator bacteria have been utilized for the assess- ment of bacteriologically unsafe waters. However, a demand for increased water quality assurance has created renewed interest in the natural relationships of enteric pathogens and indicator bacteria (14, 31, 32). The reliability of the coliform test, the utilization of Pseudomonas aeruginosa as an indicator organism, and the relationship of fecal streptococci to pollution have currently been under consideration. Furthermore, the criteria for determining these particular bacterial populations and the environmental factors capable of influencing them are becoming of utmost importance in water sanitation.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Fresno
- Department:
- Biology
- Creator:
- Wetzel, John.
- Description:
- The primary emphasis in most studies of bacteria and the relationship they have with their host is directed at the study of pathogenic species and the diseases caused by them, However, in addition to the pathogenic bacteria, there are many bacteria which are essentially nonpathogenic and can often be found in very healthy animals. These bacteria, although differing from animal to animal, perform important biological functions and in doing so affect both directly and indirectly an animal's general health. In spite of the contribution of the normal bacteria, only a few studies have been performed which attempt to determine the normal populations of even some of our most common domestic and wild animals.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Fresno
- Department:
- Biology
- Creator:
- Summers, Robert Wayne.
- Description:
- Meso-American squirrel monkeys (Saimiri sciureus), restricted to the narrow coastal zone of southeastern Costa Rica and southwestern Panama, are widely separated from their conspecifics east of the Andes, and have a more reduced range than indicated by Hill (1960). None occur naturally in the eastern half of Panama, the Colombian Choco, or west of the Andes in South America, with the exception noted by Hershkovitz (1972b) of a small population of squirrel monkeys he discovered in the Upper Rio Magdalena Valley in southern Colombia.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Fresno
- Department:
- Biology
- Creator:
- Stebbins, John.
- Description:
- Bush Anemone (Carpenteria californica Torr.) is a rare endemic shrub that exists within a limited range in Eastern Fresno County, California. Little floristic or vegetation research has been conducted on the species in its natural environment. The present study performed on the Carpenteria Botanical Area, within the Sierra National Forest, was undertaken with three main objectives: 1) A floristic survey of all vascular plants in the Botanical Area. 2) A mapping of the distribution of C, californica within the bounds of the Botanical Area. 3) A vegetational analysis to clarify the relationship between C. californica and associated woody species in the Botanical Area.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Fresno
- Department:
- Biology
- Creator:
- Shapiro, Gary Louis.
- Description:
- Following the methods of Gardner and Gardner (1969) and Premack and Premack (1972), others have continued human- pongid two-way communication studies elaborating upon the procedures of both the former investigators. Fouts (1973), after the Gardners, has employed hand gestures or modified American Sign Language as a medium of communication in his work. Rumbaugh and his group (1973), following Premack, have used an artificial symbol language in a system in which a computer can mediate dialog between subject and experimenter. It is not surprising that the subject of. study has been the chimpanzee (Pan troglodytes). Except for an attempt to teach a gorilla (Pan gorilla) gestural language,1 linguis- tic studies with pong ids have been exclusively with chimpan- zees. This has been primarily a matter of availability and economics since the chimpanzee is only now becoming threatened in its natural environment, whereas the other two species, the gorilla and the orangutan (Pongo pygmeaus), have been endan- gered for quite some time (MacKinnon, 1975, van Lawick- Goodall, 1971, and Bourne, 1971).
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Fresno
- Department:
- Biology
- Creator:
- Schaeffer, Barbara Jo.
- Description:
- Farm ponds are small man-made resevoirs used for watering of farm animals, irrigation and fishing. Because of their small size, farm ponds are susceptible to rapid eutrophication which can cause growth of noxious or poisonous algae, unpleasant odor from decaying plant material, and loss of aesthetic value. Farmers are interested in farm pond management practices to produce high yields of fish without unnecessary algal growth.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Fresno
- Department:
- Biology
- Creator:
- Page, Peter John.
- Description:
- This three year study (1970-1972) was undertaken to document reproductive success in a colony of great blue herons at the San Joaquin River Heronry, Merced County, California. Quantitative data were collected on incubation period, clutch size, hatching dates, fledging success, and nesting mortality. Studies during the 1970 and 1971 nesting season were part of a research program conducted by the California State Department of Pish and Game to document reproductive success in several central California heronries.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Fresno
- Department:
- Biology
- Creator:
- Mulligan, Michael.
- Description:
- Declining trout harvests in rivers on the west slopes of the Sierra Nevada constitute a major fishery management problem in California. As part of a research team investi- gating this problem in the Kings River, my research consisted of documenting seasonal movement and annual use by fish of Mill Flat Creek, a tributary to the Kings River. Life history and ecological data are reported for each associated species of fish. Also discussed are the physico- chemical conditions, and species interactions within the creek.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Fresno
- Department:
- Biology
59. Morphological and physiological studies of macroaleuriospore germination of Microsporum gypseum.
- Creator:
- Lin, Jun-pai.
- Description:
- The germination of asexual spores of most fungi requires a suitable substrate and a compatible environment. Heat-induced macroaleuriospore germination in Microsporum gypseum has been studied previously by Leighton and Stock (1968). They mentioned that the preincubation of macro- aleuriospores at 37 C was necessary for obtaining 85 to 90% germination of spores with or without the presence of exogenous nutrients. They were unable to obtain above 50/£ germination of spores under normal nutritional conditions at temperatures below 33 C. On the basis of these observations, a series of physiological and biochemical studies was con- ducted by these authors. They found that the germination process was initiated by 2 hours and was completed by 7 hours in physiological saline at 37 C. They concluded that the involvement of a protease was the event essential for germination.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Fresno
- Department:
- Biology
- Creator:
- Kelly, Barry.
- Description:
- Formation of endospores by aerobic bacilli serves as a model system for answering basic questions related to development and cyto- differentiation in general. An important aspect of sporulation is that different bacilli seem to form spores by going through the same basic morphological changes. Differentiation begins by the formation of an asymmetric crosswell septum which divides the prespore (forespore) region from the vegetative mother cell. The prespore region becomes engulfed by another layer of membrane to form the double membrane bound forespore. Final maturation occurs with the sequential appearance of cell wall primordium adjacent to the inner forespore membrane, deposition of the mucopeptide cortex within the double membrane, and formation of the proteinaceous coat outside the outer forespore membrane. Concomitant with these morphological changes is an entire battery of biochemical changes which occur during sporulation. Alterations in DNA, RNA, and protein synthesis have been detected in sporulating cells (6). The overall effect is that poor growth conditions derepress regions of the bacterial genome (the precise mechanism is currently not known) which contain the genetic information for making cryptobiotic structures called endospores. Expression of this genetic information results in the disappearance, alteration, or new production of specific proteins, and the production of sporulation specific m-RNA and t-RNA molecules.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Fresno
- Department:
- Biology
61. Geographic variation and taxonomy of Dipodomys nitratoides from the California San Joaquin Valley.
- Creator:
- Hoffmann, Walter McKie.
- Description:
- There has been some uncertainty regarding the subspecific variation, distribution, and resultant taxonomy Dipodomys nitratoides. It was the purpose of this study to critically examine the geographic variation of this species and, on the basis of that variation, attempt to establish the taxonomic status and distribution of the subspecies.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Fresno
- Department:
- Biology
62. Induction and physiological-genetic characterizations of selected Staphylococcus aureau strains.
- Creator:
- Elhag, Tahani.
- Description:
- The L-Form of Staphylocoecus aureus is of interest from a clinical point of view since it has been often associated with certain diseases. S- aureus L-Forms have been isolated from recurrent osteomyelitis (Rosner, 1968)., In addition, Kagan (1972) reported isolation of L-Forms of S aureus from recurrent furunculosis, from blood cultures of a leukemia patient, and from sputum of some patients with cystic fibrosis. Because L-Forms are cell wall deficient organisms, they may survive in vivo, under conditions that would not allow survival of intact bacteria. The lack of cell wall or presence of cell wall remnants in these variants has been established by chemical analysis. Pratt (1966) found that L-Forms of S_. aureus contain negligible amounts of muramic acid and no teichoic acids. Chatterjee et al. (1967) reported the presence of only mucopeptide intermediates and only some of the enzymes responsible for cell wall synthesis in this organism.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Fresno
- Department:
- Biology
63. Food preferences of Triopha maculata and Triopha carpenteri on the Monterey Peninsula, California.
- Creator:
- Eastman, James Kirbye.
- Description:
- Faculty and students of the Moss Landing Marine Laboratory, Moss Landing, California, have been conducting population studies of the dorid nudibranchs in the intertidal of the Monterey Peninsula, California, since 1969. Throughout the studies two closely related species, Triopha maculata MacFarland, 1905 and Triopha carpenteri (Stearns, 1873), were found to be dominant in abundance, making it a matter of some interest to determine how two such apparently similar species could coexist. If considerable competition occurred between the two species, how were such large populations maintained? If, on the other hand, no significant competition existed, how was it avoided.? As food is one of the key resources for which competition may occur (Emlen 1966) , the quantitative study was limited to the relative food preferences of the two species of Triopha, in order to assess the extent to which significant competition might exist for food resources.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Fresno
- Department:
- Biology
- Creator:
- Dorman, Douglas.
- Description:
- It has been reported by Chew (1965) that all pathways of water exchange are reduced when mammals are subjected to dehydration. With few exceptions, evaporation is the major loss, and usually the greatest absolute conservation of water is realized by the reduction of urine and fecal water loss (Chew, 1965). Research dealing with the water economy of kangaroo rats (Dipodomys) has primarily centered on Eb_ merriami. This species is the most polytypic and widely distributed species of the genus and characteristically occupies extreme desert habitats (Carpenter, 1966). Extensive studies by Schmidt-Nielsen and Schmidt-Nielsen (1951) and summarized by Schmidt-Nielsen (1964) have reported EU_ merriami's structural, physiological, and behavioral adaptations to the conservation of water. Using the extensive studies by the Schmidt-Nielsens as a basis of comparison, other researchers have studied the extent to which the availa- bility of water in different habitats acts as a factor in selection. It is to be expected that the water require- ments and exchanges of each species of mammal have evolved into a "fit" with its environment which precludes its expanding its range into environments that are more rigorous (Chew, 1965).
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Fresno
- Department:
- Biology
- Creator:
- Cockerham, William.
- Description:
- When pasture land, is grazed by cattle the composition of the herbaceous vegetation is changed from that of the ungrazed state and the ecology of the pastoral habitat will be variously affected. The object of this investigation was to examine the distribution of small mammal populations on two areas, one moderatly grazed and the other not grazed, to determine the effect of grazing on small mammal distribution. The importance of small mammal habitat preference was also to be determined.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Fresno
- Department:
- Biology
- Creator:
- Canaday, Jim.
- Description:
- Taxonomic and general natural history studies have been complemented by physiological and energetic considerations. This additional emphasis is necessary if the functional role that each species plays in the ecosystem is to be determined. To ascertain each species' energetic relationship, data on food habits, behavior, population dynamics and metabolic physiology must be collected. Once collected, these data can be incorporated into an energetic mosaic evaluating each species capability for capturing and utilizing a limited energy source. Ideally, these energy mosaics can be combined to provide an insight into ecosystem dynamics and to serve as tools in the prudent management of ecosystems.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Fresno
- Department:
- Biology
67. Maternal provisioning and the effect of stress on tetrodotoxin production in terrestrial vertebrates
- Creator:
- Susbilla, Calvin Bron
- Description:
- Chemicals are often sequestered by various organisms to defend against predators by making prey noxious, and in some cases, toxic. Sequestration has been observed in various taxa, however, there are few vertebrate examples available. Further, little is known about maternal provisioning of sequestered toxins. The Asian natricine snake, Rhabdophis tigrinus, sequesters bufadienolides from toxic toad prey and allocates toxins to offspring. Likewise, the common garter snake, Thamnophis sirtalis, sequesters the neurotoxin tetrodotoxin (TTX) in its liver from newt prey. However, maternal provisioning in this natricine snake has yet to be investigated. To investigate maternal investment of TTX in T. sirtalis, gravid snakes from Benton County, Oregon were offered toxic newts for consumption. The liver of female snakes and neonates were later dissected and TTX levels were quantified using a Competitive Inhibition Enzymatic Immunoassay. Dams were found to possess TTX in their livers, whereas, TTX was not detected in any neonate liver samples.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Bakersfield
- Department:
- Biology
- Creator:
- Samuelian, Dale.
- Description:
- A population of three-spined sticklebacks Gasterosteus aculeatus L. from the San Joaquin River below Friant Dam near Fresno, California, was found to be infected with the plerocercoid larval stage of a pseudophyllidean cestode, Schistocephalus solldus (Muller, 1776). Schistocephalus solidus belongs to the class Cestoidea, subclass Cestoda, order Pseudophyilidea, family Dibothrio- cephalidae. During the plerocercoid larval stage it is a coelomic tapeworm of the three-spined stickleback Gasterosteus aculeatus. Members of this genus are widely distributed in many parts of the world, with the majority of infections being reported in Great Britain and Ireland (Smyth, 19-4-6; Hopkins and McCaig, 1963; Arme and Owen, 1967; Chappell, 1969a,b; and Pennycuick, 1971a, b, c, d. In California, S. solidus has been studied by Markley (19^-0) and Haderlie (1953). The present study will: (1) demonstrate the seasonal incidence and variation of the parasite infection, (2) indicate the differences in the sizes of the infection in stickle- backs of different sexes and sizes, and (3) show the frequency distributions of the parasite within the host population.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Fresno
- Department:
- Biology
- Creator:
- Rossitto, Joseph James.
- Description:
- Chromosomes were analyzed from the mitotic bone marrow of nine mountain pocket gophers (Thomomys monticola J. A. Allen, 1893). All the specimens, collected from three different localities in the'Sierra Nevadas, had a diploid number (2N) of 40. Animals from two localities exhibited slight variations in chromosome morphology. Pocket gophers from Lake Tahoe possessed a fundamental number (FN) of 76 while those from Huntington Lake and Kaiser Pass Meadow had a FN of 74. The difference in the karyotypes is attrib- uted to non-Robertsonian variation: pericentric inversions and reciprocal translocations.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Fresno
- Department:
- Biology
- Creator:
- Restani, Mark.
- Description:
- The structure of intermittent streams has been described by Abell (1956) . Her work was based on the analysis of Dry Creek, Fresno County, California, which she considered a typical intermittent stream. An earlier work (Stehr and Bransen, 1938) had given the faunal makeup of a similar stream in Southeastern Ohio. The effect of drought on the fauna of two small mountain streams turning them into intermittent streams is described by Hynes (1958) and Kamler and Riedel (1959). The apparent patterns of recolonization of temporary streams with the return of water is discussed by Abell (1956), Clifford (1966) and Harrison (1966), and a generalized overview of the subject of intermittent streams is presented by Hynes (1972). A tributary of Cottonwood Creek, which unlike Dry Creek has no permanent pools, was followed from November 20, 1972, just after the first rains, until the stream dried up on June 15, 1973, to establish the diversity of insect forms, their temporal sequences and to permit speculation on reinvasion patterns and habitat preferences or limitations. Samples were taken once every other week with a surber sampler and an aquatic net. Stream current was measured with a Gurley Pygmy Current Meter. The stream proved to have a diverse insect fauna as well as a variety of other forms including molluskans, annelids, acarines, crustaceans, amphibians and reptilians. One fish, Gambusia sp., was taken, a likely contaminant from year-round water sources near the stream.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Fresno
- Department:
- Biology
- Creator:
- Nunheimer, Lillian.
- Description:
- An estuary is a coastal area where river water meets oceanic water. A characteristic of a tidal estuary is brackish water which shows fluctuations in salinity. These fluctuations are due to the diurnal periodicity of the tide and the influx of fresh water from precipitation. The differences in water density due to salinity and temperature prevent immediate mixing of the two water types and stratification frequently occurs. The river water usually contains a high concentration of nutrients which promote larger phytoplankton populations in most estuaries than those in adjacent oceanic areas (Sverdrup et al. 19*4-2).
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Fresno
- Department:
- Biology
- Creator:
- Medeiros, Joseph.
- Description:
- Microsporangial development in angiosperms is a well documented process. In contrast, difficulties such as availability of material, prolonged development, and problems in sectioning have made information concerning microsporogenesis in gymnosperrns scanty. Within the gymno- sperms, most studies have been in groups such as the Pinaceae.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Fresno
- Department:
- Biology
- Creator:
- Flores, Emmanuel
- Description:
- Probiotics are live microorganisms that provide therapeutic effects to their consuming host’s gastrointestinal tract and immune system. Although they are considered “generally recognized as safe” (GRAS) by the FDA and are added to a plethora of probiotic products, probiotics are known to display patterns of antibiotic resistance and impurity. In this study, we determined probiotic strains of Bacillus were resistant to clinically relevant antibiotics. Kirby-Bauer disc diffusion assays were performed to assess if any of these probiotic Bacillus strains were resistant to clinically relevant antibiotics. In B. coagulans and B. subtilis strains, we observed resistance and intermediate sensitivity to various antibiotics. We used the Comprehensive Antibiotic Resistance Database (CARD) to computationally analyze genomes and plasmids of these probiotic Bacillus strains and probiotics from multi-strain supplements for genes that confer antimicrobial resistance (AMR) and found genes conferring resistance to all classes of antibiotics. In addition, we assessed the purity of the active species content in multi-strain probiotics to identify which probiotic and contaminant is a potential vector of AMR. In the three supplements we found various contaminants and probiotics containing AMR genes on chromosomal and plasmidic elements. Taken together, results from this study provide insight into the potential risks of AMR and impurities in probiotic supplements.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Fresno
- Department:
- Biology
- Creator:
- Horgan, Sara Kathryn Anderson.
- Description:
- The effects of two mammalian viruses (SV40 and reovirus) were observed on a homeothermic and on a poikilothermic cell line. Propagation of these viruses in both types of cells could indicate shared biochemical receptor sites on the two types of cell lines which are recognized by the viruses, allowing them to adsorb to ana penetrate the cells. The host cells included a poikilothermic cell line from fathead minnow (FHM) and the homeothermic African green monkey kidney cell line (BSC-1). Virus effects were demonstrated by observations of cytopathic effects (CPE) on stained coverslips of infected cells and unstained roller tube monolayers. The discovery that a mammalian tumor virus could be grown in FHM cells would facilitate experimental studies on these viruses. FHM cells are a practical laboratory host system for viral studies, since these cells are easily detached from a glass surface for stock culture subtransxers and, due to their lower rate of metaoolism, the PRw cells produce acids in the medium much slower than many cell lines of homeothermic origin such as BSC-1 cells. Acid production in cell cultures is undesirable, since it contributes to cellular degeneration.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Fresno
- Department:
- Biology
- Creator:
- Grendahl, Jan.
- Description:
- new concept in medical bacteriology was opened for investigation in 1935 when Kleinberger reported she had successfully separated a cell wall deficient variant from a normal culture of Streptobacillus moniliformis (Kleinberger, 1935). Kleinberger denoted the new bacillus type an "L-form" in honor of the Lister Institute. L-forms were first induced from gram negative rods (Kleinberger, 1935), but since then have been induced from gram positive rods and cocci as well as gram negative cocci (Hymans, 1969).
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Fresno
- Department:
- Biology
- Creator:
- Barreto-Zavala, Yaneth
- Description:
- Xylella fastidiosa is a xylem-obligate plant pathogenic bacterium that causes disease in diverse crop plants. In grapevines, the infection is known as Pierce’s disease, which is limited to regions with warmer climates and fails to appear in cold climates. In previous research, it was observed that grapevines infected with X. fastidiosa can lose the infection during the winter season. However, this phenomenon (termed “cold curing”) is not completely understood. X. fastidiosa lacks certain aspects of bacterial cold response, including cold-inducible cold shock proteins. Due to the known role of cold shock proteins in RNA stabilization, this study investigated the role of RNA metabolism in X. fastidiosa in response to cold temperatures. Specifically, we characterized a purine nucleotide phosphorylase gene (pnp). We utilized knockout mutagenesis to evaluate the role of pnp in X. fastidiosa cold survival, in planta virulence, and cold-inducible gene expression. Our results suggest that X. fastidiosa pnp does not have reduced survival at 4℃ or in planta, but it is less virulent than the wild type, Stag’s Leap strain. In addition, X. fastidiosa Pnp does not show enzyme activity characteristic of that of a purine nucleoside phosphorylase.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Fresno
- Department:
- Biology
- Creator:
- Eckman, John.
- Description:
- The western foothills of the Sierra Nevada are dotted with small earthen reservoirs which are maintained by landowners primarily as a source of water for livestock. Most of these farm ponds have been stocked with warmwater gamefish such as largemouth bass, bluegill, green sunfish and catfish, thus creating a source of recreation for fishermen and a source of revenue for the landowner, who usually charges a fishing fee. In most cases, the landowner has done little to maintain the farm ponds, and several of them have been successful in fish production for decades without management. However, in the dry summer and fall months some farm ponds undergo drastic changes which result in massive fish deaths.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Fresno
- Department:
- Biology
- Creator:
- Clayton, Bruce.
- Description:
- Mountain meadows offer aesthetic values and provide feed for cattle and wildlife, making it important for both financial and recreational reasons that they be maintained at maximum productivity. At the present, little is known about vegetation structure and floristic composition of meadows. This information is important to understanding meadow ecology, and to developing habitat studies of animals that frequent these areas. This project was undertaken to supply data about these subjects and had three major objectives (l) to compile a floristic inventory as a base line from which meadow vegetation can be studied; (2) investigate the structure of meadow vegetation; (3) determine animal grazing rates on the meadows.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Fresno
- Department:
- Biology
- Creator:
- Kelly, Erica Crystal
- Description:
- My results suggest that Desert Kit Foxes in the Mojave Desert in California prefer to consume rodents and invertebrates, but will prey upon a variety of other items, especially when preferred prey has declined due to drought or seasonal conditions. Overall, my study supported the scientific consensus that kit foxes are specialists on heteromyid rodents. Invertebrate prey, though, does provide an important supplement when rodent prey is less available. For Coyotes, the most frequently occurring items consumed were rodents and lagomorphs. Thus, Desert Kit Foxes and Coyotes did eat many of the same prey items throughout the study which could promote exploitative competition, but they did so in varying frequencies depending on the year and season.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Bakersfield
- Department:
- Biology
- Creator:
- Kalouch, Mirva
- Description:
- In order to further investigate the presence of these antibiotic biosynthetic pathways, this study focused on ten genes and the identification of genes that code for enzymes in these antifungal and antibacterial pathways; Flagellin (hag), Mucosubtilin synthetase B (mycB), Translocationdependent antimicrobial spore component (tasA), 4’-phsophopantetheinyl transferase (surfactin) (sfp, sfpA, and sfpAA), Subtilin (spaS1 and Spas2), Iturin A (ituA), and Subtilosin A (sboA) (Yang et al. 2015, Velho et al. 2013, Hassan et al. 2010, and Mora et al. 2011). I hypothesize that our 16 Bacillus samples will contain genes that are known to be involved in known antibiotic biosynthetic pathways.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Bakersfield
- Department:
- Biology
- Creator:
- Armstrong, John William.
- Description:
- Three out of five wild populations and a laboratory- population of Indian meal moth, Plodia interpunctella (Hubner), were found resistant to malathion. A malathion-susceptible Indian meal moth population, stressed with malathion, showed a 110-fold increase in resistance after five generations. Reciprocal crosses of malathion—resistant and -susceptible Indian meal moth populations showed that malathion—resistance was not a sex—linked character and the genes, while not simple, allowed for the rapid selection of resistance.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Fresno
- Department:
- Biology
- Creator:
- Kaur, Prabhjeet
- Description:
- Coccidioidomycosis, also known as Valley Fever, is a re-emerging infectious disease of the American continent. Coccidioidomycosis is a respiratory disease caused by the inhalation of arthroconidia produced by the dimorphic ascomycete fungi Coccidioides immitis or Coccidioides posadasii known to live in soil environments as a saprophyte. Coccidioides sp. are known to thrive in loamy and highly saline soils. These fungi have the ability to form spores known as arthoconidia, which can survive the dry, hot summers. When soil is disturbed, spores become airborne and can cause infection when inhaled by a host. Recently, the incidence of valley fever has increased significantly in endemic areas of the pathogen such as the Western Mojave Desert and among the general public and has also affected prisoners incarcerated in correctional facilities, such as the one east of California City, our study area. The objective of this research was to determine the soil properties that are essential for the growth of Coccidioides immitis in the Northwestern Mojave Desert near California City. Different physical and chemical properties of soils such as soil pH and soil type are known to determine the distribution of plants, which can therefore indicate certain soil conditions, but these parameters also affect the growth of microorganisms and fungal communities in diverse microhabitats. The hypothesis of this project was that the presence or absence of the pathogen in the soil can be linked to yet to be determined environmental parameters and/or depends on the presence or absence of certain soil microorganisms that could act as antagonists to the pathogen. The physical and chemical soil parameters, as well as plant diversity were determined for each sampling site. In this study, culture independent techniques, such as DNA extraction followed by PCR and DGGE were used to detect the presence of C. immitis, and to determine the diversity of the soil fungal communities in 43 soil samples collected long several transects in 2014 and 2015. Results of this study revealed that the study area is highly endemic for the pathogen, but its presence could not be linked to specific soil parameters. The fungal diversity in the soil was generally low and showed the dominance of members of the Pleosporales and Hypocreales. Members of the fungal genus Ascobolus were only found in soils that were negative of the pathogen and could potentially include antagonists to C.immitis.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Bakersfield
- Department:
- Biology
- Creator:
- Singh, Krizma
- Description:
- Bladderworts, aquatic carnivorous plants, use specialized traps (with a mouth opening of about 0.2 mm in diameter) to complete their feeding strike in less than a millisecond after the trap begins to open. Suction feeding is well understood in animals with mouth diameters greater than 10 millimeters and the little we know about small suction feeders from larval fish suggests that small suction feeders are not effective. Yet bladderworts have strong suction performances despite having the same mouth size as that of fish larvae. Bladderwort generate suction flows with peak speeds of 5 m/s and reach peak speed in 1 millisecond. In contrast, larval fish reach much lower peak speeds of 1 mm/s within 10 milliseconds. Previous studies of bladderwort suction feeding have focused on the trap door mechanics rather than the mechanics of fluid flow. As it is difficult to study the real organisms due to their small size and short duration, we used fluid-dynamic scaling laws to design a dynamically scaled model and characterize the suction flows. This larger and slower model greatly facilitates the recording of data with better temporal and spatial resolution. The model comprised a linear motor and a housing with a circular test nozzle submerged in mineral oil. We combined flow visualization on bladderwort traps with measurements on the mechanical model and compare experimental data with theoretical predictions about inhalant flows. In this study, we simulated actual traps as well as traps that are smaller and slower than real traps to explore how speed affects suction performance. We also show that a dynamically scaled model provides detailed flow fields to help explore the differences between bladderwort and fish larval suction flows. Our findings largely agree with theoretical models of suction flows, which show that bladderwort traps generate flows that closely resemble inviscid flow whereas fish larvae resemble creeping flow models. This dynamically scaled mechanical model will be a valuable tool to address bio fluid-dynamic questions.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Fresno
- Department:
- Biology
- Creator:
- Coleman, Mitchell Lewis
- Description:
- Invasive annual grasses of mediterranean origin dominate large areas in the arid and semi-arid regions of the San Joaquin Valley in California and create numerous management challenges. Much of the invaded habitat would be native saltbush shrub communities (Atriplex spp.); however, the presence of these grasses may inhibit saltbush recruitment. One way this could occur is due to competition for water between the grasses and saltbush seedlings. Another possibility is that when invasive annual grasses die after setting seed, they leave behind a dense cover of residual dry matter (RDM) as dead shoots, which alters the habitat by shading the soil. I tested the hypothesis that grasses limit saltbush seedling recruitment, leading to persistently invaded grasslands and thereby inhibiting saltbush succession. I predicted that competition from grasses during the rainy season reduces soil moisture available to saltbush seedlings at the critical seedling stage of their life cycle. Furthermore, I predicted that the presence of dense RDM blankets formed during the dry season shades the soil and inhibits the natural succession of saltbush shrublands in the San Joaquin Valley at old-field areas. Moreover, I predicted that grass competition and RDM affects saltbush recruitment due to alterations in soil temperature, soil moisture, and light penetration to the ground. To address these questions, I used a combination of manipulative and natural field experiments to assess the factors affecting recruitment of the saltbush Atriplex polycarpa (Torr.) S. Watson. I conducted experiments manipulating the effects of invasive grass competition and RDM on saltbush seedling germination, mortality, and survival. I also conducted a number of comparative studies between six mature saltbush stands at Tejon Ranch, wherein I assessed differences in seedling recruitment, demographic composition, water relations, and soil conditions. The goal of the study was to more precisely elucidate mechanisms governing saltbush germination in the San Joaquin Valley. Overall, I found than invasive grass RDM functions to inhibit saltbush seed germination to a degree that precludes long-term seedling recruitment in the San Joaquin Valley. Competition between saltbush seedlings and the grasses during the wet season also inhibits recruitment to a smaller degree. Saltbush recruitment is affected by alterations to soil moisture, temperature, and light levels created by invasive grasses. I also found that older seedling survival is greater in grassy areas compared to native saltbush habitat, ostensibly due to higher pressures of herbivory in the saltbush habitat. This creates a seed-seedling conflict wherein seed germination is inhibited in grassy areas, but seedling survival is higher in grassy areas. Thus, field conditions with a low amount of RDM over saltbush seeds and no seedling herbivory are ideal for saltbush recruitment in the San Joaquin Valley. My findings are relevant for the conservation and management of important remaining saltbush habitat and the continued expansion of invasive annual grasses in the San Joaquin Valley and throughout the mediterranean-type climate regions of California.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Bakersfield
- Department:
- Biology
- Creator:
- Muñoz, Evelin
- Description:
- Fewer than 40% of students that pursue college degrees in Science, Technology, Engineering, and Mathematics (STEM) do not graduate with a STEM degree. The rate of college degree attainment in STEM is about 20% lower for women, people with disabilities, and people of color. They do not have equal access to STEM education and thus are unequally represented in STEM fields. One of the reasons students struggle in STEM are ineffective experiences in the college classroom. Active learning, also known as evidence-based teaching practices, are more effective than traditional lecture style teaching. However, despite its lack of efficaciousness, 50-75% of North American STEM professors continue to use lecture as their only teaching method. Why do most faculty not use active learning? Adoption of active learning is influenced by both factors external to an individual (time, policy, resources, student resistance) and personal knowledge and beliefs (loss of autonomy, lack of or efficacy in pedagogical skills). Prior work in this area often looks at these variables in isolation, reducing the complex world in which faculty teach into a laundry list of levers and barriers. These studies also often lack a cohesive theoretical framework to explain findings in light of broader educational and socio-psychological work. The goal of my study was a quantitative examination of variables that contribute to active learning adoption through the lens of a framework for individual-level change: The Theory of Planned Behavior I used valid and reliable surveys to examine faculty teaching practice at 7 institutions (N=424 STEM faculty), including their (a) personal attitudes, (b) norms, (c) perceived behavioral control, and (d) self-reported teaching practices. I then explored correlations among these variables using a k-means cluster analysis to find four distinct teaching-attitude-norm ‘clusters.’ The most predictive variable for the differences in clusters was faculty attitudes about teaching. I also found normative differences by cluster for women, international faculty, faculty with Asian ethnicities, and faculty from engineering disciplines. Contextual variables like class size and class layout had some effect on teaching practices, as did views about leadership and organizational support, but these variables did not explain overall cluster patterns with the same consistency as faculty attitudes about teaching.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Fresno
- Department:
- Biology
- Creator:
- Moshier, Shelby Paige
- Description:
- Sandy beaches support dynamic and diverse, but physically narrow intertidal ecosystems that are vulnerable to the effects of anthropogenic disturbance, such as coastal dredging and beach nourishment. Our study site in Morro Bay, California has been a site of coastal dredging by the U.S. Army Corp of Engineers (USACE) since the 1960’s. In February of 2017, 240,000 cubic yards of sediment were dredged from the harbor and deposited onto the beach as beach nourishment. We assessed the impacts of this beach nourishment over two years on three aspects of beach ecosystems: 1) beach width, 2) avian biodiversity, and 3) intertidal macroinvertebrate biodiversity. We designated seven sampling sites and at each collected monthly measurements of beach width, monthly avian point counts, and quarterly macroinvertebrate samples. We found spatiotemporal variation present across months and sites, and beach width at the deposition site was significantly higher than the six control sites pooled together. Avian and macroinvertebrate biodiversity was not significantly different at the deposition site compared to the pooled control sites. Our results suggest that the dredge deposition had low or very short-term impacts to both avian and intertidal macroinvertebrate biodiversity at the deposition site over our two years of sampling. Positive impacts include a wider beach at the deposition site.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Fresno
- Department:
- Biology
- Creator:
- Baumgardner, Aaron W.
- Description:
- Global-change-type drought has resulted in large numbers of woody plants suffering mortality in California during the most recent droughts from 2012-2018. These droughts are ecological droughts that impact ecosystems and trigger responses. The factors that trigger ecological droughts are not well established. One limitation of studies considering drought is the lack of a clear set of criteria used to define aspects of drought that should be examined when assessing the effect of drought on an ecosystem. The most common way to evaluate drought is to use indices that are calculated from annual metrics such as annual precipitation. Other indices are calculated on an ongoing basis and integrate both temperature and precipitation such as the Palmer Drought Severity Index (PDSI). In this work, I examined other climate extreme indices that can be used to understand woody plant dieoffs. For example, the number of days without precipitation and the intensity of storms, relative to long-term averages, are some factors that may be important in evaluating drought effects on woody plants. I applied these criteria to understand which factors best correspond to recent woody shrub die-offs in southern California chaparral shrublands. I hypothesized that there are aspects of droughts that: 1) drive the response of vegetation and 2) create tipping points that trigger ecological droughts. To test this, I coupled existing remotely-sensed vegetation data from satellites with weather-derived climate indices over 17 rainfall years (2000-2016) from field sites located in the Santa Monica, Santa Rosa, and Tehachapi mountains of southern California. Vegetation indices (NDVI, EVI, LAI, and fPAR) were calculated using Moderate Resolution Imaging Spectroradiometer (MODIS) data, and climate indices, in addition to PDSI, were calculated using daily summaries from PRSIM (Parameter-elevation Relationships on Independent Slopes Model) weather data. I found that the climate in our coastal study region has become more drought prone in the 30-year data set, whereas the desert region has become neither drier nor wetter. PDSI was more predictive of vegetation health than a combined, multiple climate extremes index developed in this study. Vegetation indices were lowest during the most intense drought years, but during longer-term droughts of lower intensity did not show continued decline. Coastal chaparral sites contain high biodiversity and many localized endemic species, which may be threatened by a warming and drying climate. Monitoring these regions using remotely sensed data may help to identify affected areas to inform land management agencies and conservation priorities.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Bakersfield
- Department:
- Biology
- Creator:
- Worrell, Joanne.
- Description:
- The subject of this study, Peromyscus boylei (the brush mouse), is found from "Honduras northward to Oregon and Utah and eastward to the Ozark Mountains" (Hooper, 1968: 50). In California, it is found characteristically in the Upper Sonoran life zone and its range extends upward into the Transition zone and occasionally into the Canadian (Grinnel1, 1933). This saxicolous mouse inhabits "wooded or brushy slopes, especially in the vicinity of oaks and usually with reach of water" (Grinnell, 1933: 177).
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Fresno
- Department:
- Biology
- Creator:
- Thormann, Barbara.
- Description:
- The Nematode suborder Strongylata is among the most important groups of nematodes to man. In addition to two species of hookworms which infect millions of people in the world today, some 40 species of Strongyles infect domestic animals, causing considerable economic loss (Chandler and Read 1961). The Strongyles cause damage to their hosts by sucking blood. Most live in the digestive tract, but the species of 2 families, the Syngamidae and the Metastrongylidae, live as adults in the respiratory passages of their hosts. A few species in other families, for example the pig kidney worm, Stephanurus dentatus, of the Strongylidae, live in other exter-intestinal habitats.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Fresno
- Department:
- Biology
- Creator:
- Kottcamp, Glenn M.
- Description:
- Sculpins of the genus Cottus are commonly found in brackish water and streams of the Pacific drainage of North America (Morris, 1961). Though common, they are infrequently encountered being small, bottom dwelling fish, rarely exceeding 1 50 mm S. The prickly sculpin (Cottus asper Richardson) is found in both freshwater and the intertidal zone from Seward, Alaska., to the Ventura River in southern California. Inland in California, Casper is found in the Sacramento River below Shasta Lake and in the San Joaquin River drainage system; coastal populations are found in fresh and brackish water from the Ventura. River northward (Krejsa,
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Fresno
- Department:
- Biology
- Creator:
- Rockwell, Richard Allen.
- Description:
- Intestinal nematodes of the family Heligmosomidae have been the subject of investigation for many years. Perhaps, the best studied species in the family has been Heligmosomoides polygyrus (Dujardin, 1845) (Nematospiroides dubius Baylis, 1926). Although much has been learned about Heligmosomoides polygyrus since its original description, some biological problems concerning it remain to be solved. The most interest- ing and important of these are in the areas of its taxonomy and physiology.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Fresno
- Department:
- Biology
- Creator:
- Baer, Alex Benjamin
- Description:
- Xylem is a complex vascular tissue that performs several functions related to the growth and survival of woody plants. These functions include the transport of water, biomechanical support, and the storage of water and nutrients. Trees are large organisms that have a highly branched growth form that is specialized to extract finite resources from the soil, move them to the shoot, and acquire limited carbon dioxide from the atmosphere. Because trees have large bodies that must transport water over long distances of changing environments, I hypothesized that their vascular system changes at different tree positions. I examined how xylem functional traits of water storage, strength, stiffness, and xylem density changed at different positions within the roots and shoots of the model tree species Populus trichocarpa (Torr. & Gray). I predicted the following: (1) xylem functional traits changed depending on tree position, most notably between root and shoot organs; (2) within organs, xylem traits differed depending upon organ diameter or position relative to the tree base. Because different parts of the vascular system may specialize in specific ways that balance the proficiency of one trait at the expense of another, I predicted (3) there would be functional trade-offs within the xylem, especially between biomechanical and storage functions. My hypotheses and predictions were tested by analyzing xylem samples from 6 juvenile P. trichocarpa trees grown in an irrigated plot at California State University, Bakersfield. For each tree, xylem was sampled at 1 m spaced positions from base to tip of the dominant root and leader shoot. My first prediction was supported; xylem density, xylem strength, and xylem stiffness were higher in shoots and lower in roots. Xylem water storage was higher in roots and lower in shoots. Support for the second prediction depended on organ and trait, where wider organ diameter and more basal positions positively associated with xylem density, xylem strength, and xylem stiffness in roots. In shoots, more apical positions and narrower organ diameters positively associated with xylem strength and stiffness, but shared no relationship with xylem density. Xylem water storage did not correlate with organ diameter or position within roots or shoots. I found that roots and shoots appear to be specialized, with roots having greater hydraulic storage with reduced biomechanical support, and shoots having biomechanically reinforced xylem with minimal water storage. These findings support the predicted trade-off of xylem traits across organs but not within them. My hypothesis was supported: the tree vascular system changes at different tree positions. Intra-organismal examinations can be used to find trade-offs and changes in vascular systems across plant bodies. Understanding how xylem functions differ throughout tree bodies is important in understanding how these terrestrial plants can maintain towering canopies and endure numerous environmental challenges over decades of growth.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Bakersfield
- Department:
- Biology
- Creator:
- Preston, Wayne.
- Description:
- Inauguration of the embryonic development of the vertebrate nephros begins within the cranial reaches of the intermediate mesoderm. The anterior portions of this mesoderm give rise to the nephrotomes which are the forerunners of the first nephrons. Since these nephrons form in the anterior position and are the first to appear, they are collectively called the pronephros of "head-kidney." Each individual nephron is unfortunately termed a pronephric tubule
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Fresno
- Department:
- Biology
- Creator:
- Platzek, James Thomas.
- Description:
- This research project bears upon a number of fields of study, including physiology, biochemistry and psychopathol- ogy. The experiment was designed to create an altered behavioral state by the stress of sensory deprivation. The altered behavioral state can be recognized by some physiological indices of behavior: concentration of the brain amines serotonin and norepinephrine; alterations in locomotor activity, brain weight, and body weight. The information derived from these indices contributes to each of the fields of study mentioned. However, the relationships between these seemingly diverse fields and this project needs to be developed.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Fresno
- Department:
- Biology
- Creator:
- Lopez, Rachel L.
- Description:
- Captive breeding is a critical management strategy in the recovery and preservation of certain threatened and endangered species. Programs that implement captive breeding must maintain a balance between preserving the genetic purity and genetic diversity of a population in order to build a viable group of individuals for future reintroduction. This may be difficult due to a limited number of extant wild individuals for establishment of founder populations, leading to an increased risk of inbreeding or outbreeding depression in subsequent generations. In this study, I worked in collaboration with 24 zoos, museums, and aquariums through the Western Pond Turtle Species Survival Plan Sustainability Project to aid in conservation of two threatened and endangered freshwater turtle species through captive breeding. As individuals of the two different species can appear morphologically identical, I used DNA sequencing to identify wild-bred Northwestern (Actinemys marmorata) and Southwestern Pond Turtles (Actinemys pallida) to build captive brood stock of both species. Relatively few studies have assessed conservation efforts in consideration of two genetically distinct species within the genus Actinemys as the majority of research on this clade was done before the discovery of a second species. Here, I analyzed the nicotinamide adenine dehydrogenase subunit four (ND4) mitochondrial gene to identify species and geographic origin for 133 captive pond turtles including 71 members of A. marmorata and 62 A. pallida individuals. Results of this study were used to inform captive breeding program collaborators so that husbandry is managed in consideration of species, geographic origin, and the subsequent risks of outbreeding and inbreeding depression.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Fresno
- Department:
- Biology
- Creator:
- Larocca, Ronald.
- Description:
- No Abstract or Summary.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Fresno
- Department:
- Biology
- Creator:
- Johnson, Margaret Tupper.
- Description:
- This pilot study was designed to test the null hypothesis that tnere is no significant difference between the information obtained by the indigenous Mexican Health Worker on the initial visit to a Mexican patient and that obtained by the professional nurse. The purpose was to seek an answer to the question: Can a valid nursing diagnosis be made on the basis of information obtained on the initial visit to a patient of Mexican origin?
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Fresno
- Department:
- Biology
- Creator:
- Johnke, Roberta.
- Description:
- This study was undertaken to investigate seasonal acclimatization in two populations of Hyalella azteca as measured by their oxygen consumption. One population was taken from a high Mg habitat and one from a low Mg environment. No significant seasonal differences between the two populations appeared to exist except during fall when the high Mg population showed lowered rates while the low Mg population increased its oxygen uptake. Similarity between summer and winter rates for both populations indicates that the seasonal patterns of oxygen consumption are probably due to some factor(s) other than temperature. Differing water types also apparently have little effect on m oxygen consumption with only slightly lowered oxygen consumption seen in water from the opposite source which may indicate a shock reaction as no time for acclimation to a new aquatic medium was given. Analysis of variance tests yielded F values which indicated that oxygen uptake patterns for the two populations studied were significantly influenced by an interaction of the factors studied in this project and most likely other factors not investigate
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Fresno
- Department:
- Biology
- Creator:
- Huang, Louise.
- Description:
- Penicill ium exnansum is a common fungus occurring in the organic debris in soil. It can also be found in food products, such as grains, cereal products, eggs and chickens (Raper and Thorn, 194-9). However, it is most common in ripe fruits such as apples and other pomaceous types from which it has been isolated (Sommer, 1967). Workers in the fields of fruit storage and distribution find it to be the principal agent responsible for losses from storage rot. Spores of the fungus are carried from the field onto the surface of the fruit, where they germinate and enter through cuts and abrasions of the cuticle and epidermis. Thus it is of considerable importance in agricultural economy to control the growth of the fungus. However, detailed information on the growth ox bhxs fungus, especially on the spore germination, is lacking in the literature. Only a few reports briefly discuss the growth of this fungus. The present work reports experiments on the changes of nucleic acids and protein during spore germination and the environmental factors affecting the process. The work provides a foundation for further investigation on the control of the fungal growth.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Fresno
- Department:
- Biology
- Creator:
- Cornel, Megan
- Description:
- Pseudomonas aeruginosa is an opportunistic pathogen that commonly causes serious nosocomial infections. P. aeruginosa’s virulence is derived from its large genome that allows adaptations to many environments and high antibiotic resistance. Gene sequences and pathways linked to bacterial survival or virulence need to be characterized before being chosen for therapeutic targeting to combat infections. One such set of genes are those leading to the production or activity of glutathione (GSH). GSH is a low molecular weight thiol that P. aeruginosa produces as a redox buffer that significantly contributes to its virulence. Previous studies have shown that P. aeruginosa transposon mutants defective in gshA (the first step of the glutathione pathway) have decreased virulence and increased susceptibility to thiol-reactive antibiotics. Genes encoding glutathione reductase (gor) are another possible target to stunt the P. aeruginosa oxidative stress response. The Gor enzyme maintains cellular redox homeostasis which resists oxidative stress. We obtained a transposon mutant disrupting gor (gor::tn) and generated a gor complement strain (MCgor) in the transposon background. When compared to P. aeruginosa wild type (MPAO1) and MCgor, gor::tn had similar growth and swarming motility capabilities, greater sensitivity to oxidative stressors, and decreased biofilm, pyocyanin, and persister cell production. Surprisingly, gor::tn outcompeted Staphylococcus aureus to a greater extent than MPAO1 did in mixed species competition assays. These comparisons are beneficial to the characterization of gor and add further support to develop antibiotics targeting the glutathione pathway.
- Resource Type:
- Masters Thesis
- Campus Tesim:
- Fresno
- Department:
- Biology
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