Transducing phages were sought among temperate phages harbored by coryneform and glutamic acid-producing bacteria. By using a nonlysogenic subline of Brevibacterium flavum strain 2247, as the phage indicator, twenty-four temperate phages were isolated from strains of coryneform and unidentified glutamic acid-producing bacteria. Phage CP-119 transduced various markers at frequencies of around 10-7, and the addition of 4mM cAMP to recipient cultures stimulated the transduction. Phage CP-123 transduced the trp marker at a frequency of approximately 10-6 when 1.2M MgCl2 was added to the reaction mixture. Characteristics of these transducing phages and of the lysogeny states of glutamic acid-producing bacteria were discussed.
The fine structure of yeasts capable of utilizing methanol as the sole source of carbon, Candida sp., Saccharomyces sp., and Torulopsis sp., was studied by electron microscopy. Many large microbodies were observed in clustered form in methanol-grown cells. They were observed as refractile granules under a phase contrast microscope. The membrane of the microbody was not stained by a method which specifically stains the plasmalemma, and an asymmetric distribution of the particles between the freeze-fractured half membranes was demonstrated. Microbodies in cells at the stationary phase of growth contained crystalline inclusions; crystalloids from Candida showed a tetragonal pattern, while those from Saccharomyces a hexagonal one. The development of microbodies was studied both during normal growth in the methanol medium and during the period of adaptation which occurs upon transfer from glucose to methanol medium. The possible modes of synthesis of the structure were discussed.
Microbiological experiments were carried out to obtain information about quantitative ecology of microorganisms around Syowa station in Antarctica throughout the year and to isolate psychrophiles. Temperature determines whether microorganisms can grow or not. It, however, seemed that quantity of nutritional materials as well a s temperature determines the general distribution and the seasonal change of microorganisms. No clear result concerning microorganisms in air could be obtained. Many psychrophiles, especially 26 obligate psychrophiles which had maximum growth temperatures around 20°, were isolated.
DNA hybridizations, base composition determinations, and tests for physiological reactions were performed on 10 isolates of Nocardia asteroids differing in microscopic colonial morphology, carbon compound utilization, and virulence for mice. One strain was eliminated from the species by all three methods and identified as N. otitidis-cavarium (N. caviae). Relatedness among the remaining 9 isolates, expressed as relative percentage binding at two temperatures, fell into two groups. The range of base composition of the DNA from these isolates was 67.7 to 69.2% GC. Formal subdivision of the taxon based on variations in physiological reactions and DNA homologies was judged to be premature.