Thesis

The distribution and physiology Sporosarcina ureae

Fifty-one strains of Sporosarcina ureae were isolated from 198 soils by plating diluted soil samples onto a complex agar medium containing 1. 5% filter sterilized urea. S. ureae was found to be widely distributed the United States and in various parts of the world. The primary habitat of this organism appears to be concentrated in certain urban soils closely associated with the activities of man and especially of dogs. However, a variety of soils cannot support growth of S. ureae. This organism was not found in soils obtained from zoos, corrals, stables, grazing lands, deserts, or from cultivated fields. Nor was it found in salt water samples. Sixty-one strains of this organism were tested for their ability to utilize 45 different organic compounds as sources of nitrogen, carbon and energv, or as growth factor requirements. The vast majority of strains required only ammonium salts for a nitrogen source but all of the organisms showed limited ability to metabolize carbon sources. Sugars are not utilized or are utilized very poorly, and glucose could not be attacked by any strain. Acetate (or butyrate) and glutamate are apparently universal substrates. The overall metabolic pattern was one of random variation but there was a clustering of strains according to growth factor requirements. The pattern that emerged was that of gradation in growth factor requirements ranging from organisms which required no growth supplements to those organisms whose nutritional requirements are complex. In general, the ecology, morphology, cultural characteristics, or biochemical reactions revealed no consistent differences that could be correlated with nutritional differences . Nor did this study reveal a constellation of differential characters that would permit recognition of additional species of Sporosarcina. The results did suggest that the leading criterion for species identification and classification may be the nutritional differences shown by this organism.

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