- Volume 77, Issue 2, 1973

SUMMARY: As the interval between methanol additions to methanol-limited cultures of Pseudomonas methylotropha was increased beyond 20 s the yield of bacterial dry wt/g of methanol fell significantly. Discontinuous methanol additions also caused cycling in the values of a number of parameters, including pH, dissolved oxygen tension, CO2 production and amino acid pool concentration. It is suggested that after each addition of methanol a burst of growth occurred, followed by a period of starvation. These observations are discussed in the light of continuous culture practice and theory.

SUMMARY: The results of the identification of 1079 reference strains of Gram-negative, aerobic, rod-shaped bacteria by a probabilistic method in a computer are given. Comparison of identification by conventional methods and by computer showed that 90.8% of fermentative and 82.1% of non-fermentative strains could be identified on the best available probability matrix. Many of these strains were atypical and had caused difficulty in identification in the medical diagnostic laboratory. The implications of various factors in successful computer identification are discussed and the results are given for each taxon by genus and species.

SUMMARY: The methods incorporated in the computer program used in a trial of computer-aided identification of bacteria are described. The identification method is based on Bayes's theorem and allows for dependent tests and missing data in the probability matrix. It was found useful in developing the method to take account of the occurrence of errors in bacteriological testing. The method suggests a definite identification only if the Bayesian probability of one of the taxa exceeds a threshold level; if not, a separate procedure selects the best tests to continue the identification.

SUMMARY: Numerical analysis of published standard descriptions of the eight species of Debaryomyces, 48 species of Pichia and the single species of Wingea failed to distinguish separate genera. It is proposed that they be combined as a single genus Pichia of 41 species, three of which were formerly allocated to the genus Endomycopsis. The genus Hansenula, of 20 species including Pachysolen tanno-philus and three former species of Endomycopsis, is closely related to the genus Pichia and is distinguished only by the ability of Hansenula species to assimilate nitrate. In the genus Schwanniomyces the number of species is reduced from four to two, and in Lipomyces, from three to one.