- Volume 63, Issue 2, 1970

Summary: Fusarium moniliforme utilized the purines hypoxanthine, xanthine and uric acid as sole nitrogen sources. Allantoin and urea supported relatively more growth. The methylated purines caffeine and theobromine were not utilized. Uric acid, allantoic acid, glyoxylic acid and ammonia were detected in culture filtrates. Xanthine dehydrogenase, uricase, allantoinase, allantoicase and urease were present in cell homogenates and cell-free extracts. Uric acid was degraded to allantoic acid via allantoin.

Summary: Vegetative hyphae of Aspergillus niger rapidly converted caproic acid to 2-pentanone whereas germinating spores carried out the transformation slowly and ungerminated spores not at all. Glucose stimulated ketone production by germinating spores, but suppressed it in hyphae; the degree of stimulation and suppression varied with glucose concentration. This explains earlier reports that spores but not vegetative hyphae convert fatty acids to methyl ketones, since hyphae were earlier tested with high sugar concentrations, conditions where ketone formation was inhibited. Glucose disappeared from cultures containing caproate even though ketone production was inhibited, and glucose disappearance was paralleled by gluconic acid accumulation in the medium. These findings suggest that free fatty acids may play an important role in the regulation of metabolic pathways in A. niger.

Summary: Both wall and membrane teichoic acids from Lactobacillus helveticus ncib8025 are glycerol phosphate polymers partially substituted with α-d-glucosyl residues. The membrane teichoic acid, isolated as a complex with lipid (lipoteichoic acid), was antigenic when injected into rabbits with Freund’s adjuvant. The α-d-glucosyl substituents are primarily responsible for the serological specificity of the membrane antigen, and account for the reaction of wall teichoic acid with antisera to the membrane teichoic acid. Glycerol teichoic acids either differing in or lacking sugar substitution may cross-react and the significance of these observations is discussed.

SUMMARY: β-Glucotransferase was demonstrated in mycelial extracts and culture filtrates of Verticillium albo-atrum grown on 2 % cellobiose as the sole source of carbon. Analysis of the mycelium indicated relatively large amounts of cellobiose and gentiobiose, as well as small amounts of a series of three oligosaccharides (DP3,4, 5) and glucose; the same compounds were detected in the culture filtrate but at much lower concentrations (except for cellobiose) and glucose was barely detectable. Cellobiose phosphorylase was also present in mycelial extracts, and it is suggested that the production of glucose-1-phosphate from the phosphorylytic cleavage of cellobiose and its rapid utilization as a respiratory substrate explains why the fungus grows so much faster on cellobiose than on glucose. The level of these two enzyme systems is considered to be an important factor in controlling the rate of growth. The significance of the formation of oligosaccharides by the transferase system is discussed in relation to cellulose degradation.

SUMMARY: A simple, chemically defined medium is described consisting of sodium glutamate, proline, cystine, salts, and growth factors, which is suitable for the large-scale production of phase I Bordetella pertussis. More than 30 × 109 organisms/ml. were produced in 48 to 72 h. growth in shake flasks and fer- mentors. The cultures were detoxified by the addition of 0·14 % formalin to yield vaccines which were non-toxic to mice and guinea pigs and had good mouse-protective antigen levels. The antigenic stability was satisfactory after storage of the final vaccines at elevated temperatures.

Summary: The ability of a range of carbohydrates to support the growth of plasmodia of the myxomyeete Physarum polycephalum was investigated and a method for the objective study of the chemotaxis of plasmodia was developed. Plasmodia showed positive chemotaxis to solutions of glucose, maltose, mannose and peptone, and to galactose after a delay. They did not respond to sucrose, fructose or ribose. The chemotactic effectiveness of sugars paralleled their ability to support growth.

SUMMARY: Bacillus megaterium 216 was induced with d-galactose to form galactokinase (EC 2.7.1.6) in amounts comparable with those induced in Escherichia coli K12. When compared with the basal level, the increase was 20 times greater than in E. coli.

The greater the concentration of d-galactose, the greater the production of galactokinase in both protoplasts and whole bacteria. In each case the maximum amount of enzyme was induced by 5 mm d-galactose. d-Fucose, a gratuitous inducer, produced approximately half the specific activity of enzyme in protoplasts as d-galactose at any particular concentration. The yield of enzyme in the presence of an optimal concentration of d-galactose was increased when the medium was fortified with low concentrations of casein hydrolysate. The specific activities of galactokinase induced in protoplasts and in whole bacteria were respectively 148 % and 37 % greater in the presence of 0·01 % casein hydrolysate.

The maximum specific activity of galactokinase achieved after induction of protoplasts for 60 min. was 3·7 units/mg. protein compared with 12·5 units/ mg. protein in whole bacteria. However, over the first 15 min. after the addition of inducer the same specific activity of galactokinase was achieved in protoplasts as in whole bacteria.

SUMMARY: The deoxyribonucleic acid (DNA) base compositions of 12 recently isolated or new species of mycoplasmas fell within the range known for the Mycoplasma group. By DNA-DNA hybridization a new sterol-nonrequiring strain, s-743, was unrelated to Mycoplasma laidlawii or M. granularum, the latter two strains showing moderate cross-reactivity; swine strain B3 appeared to be related to M. mycoides var. capri. From these results and information in the literature, the mycoplasmas have been divided into six provisional subgroups on the basis of physiological characters, DNA base composition and nucleic acid hybridization. Some speculations are made on the significance of heterogeneity among mycoplasmas.