No abstract

StrMMARYThe systematic relationships among 54 strains of bacteria, representing principally the genera Achromobacter, Aerobacter, Alcaligenes, Eschmichia, Mima, Pseudomonas, Serratia and Streptococcus, were examined by computer methods. Seventy-one properties of these organisms were determined, and the resulting data scored in different ways (according to various proposed techniques) before being submitted to an appropriate computer program for calculation of similarity (S) values. These comparative studies indicated that better division of organisms into mutually similar groups can be achieved when data about properties which may have several alternative expressions are handled in the manner proposed by Beers & Lockhart (1962). The number of comparisons which contribute to individual similarity values should be held constant by adequate treatment of quantitative data and by adoption of scoring methods which permit comparisons between ' negative ' properties. It may be useful to employ distance (D = log,l/S) rather than similarity as the primary measure of relationships among groups of organisms.

A nutritional study was made of five strains of Bacillus coagulans obtained from various culture collections. These five strains were descendants of two original isolates; three had been derived from one parent culture in years past and the other two were transfers from another parent culture. Therefore, the five cultures should have represented two distinct groups of genetically identical cultures. Three of the strains obtained from one culture collection had become methyl red-negative and sorbitol-negative and had gained abilities to hydrolyze gelatin and ferment arabinose. Nutritional requirements of the five cultures, determined at 37, 45, and 55 C, differed considerably among strains; however, thiamine and biotin were required by all cultures at all temperatures. Aspartic acid was stimulatory at 37 C and was required at 45 C; folic acid, basic amino acids, and certain other nutrilites were required at 55 C. Adenine supplementation was necessary for two strains at 55 C to prevent autolysis; this phenomenon is discussed. The response of these organisms to both serine and the basic amino acids at the three growth temperatures seems especially significant. The media devised for the growth of the five strains of B. coagulans used in this study permit excellent growth at three incubation temperatures.

rate lyase and malate synthetase were found in cell-free extracts of Bacillus cereus T. The patterns of synthesis of enzymes of the glyoxylic acid cycle were dependent upon the medium in 1 This paper is based on a dissertation submitted by the senior author to the faculty of Iowa State University in partial fulfillment of the requirements for the Ph.D. degree in Bacteriology.