An enzyme which lysed viable yeast cells was purified about 75-fold from the culture fluid of Arthrobacter luteus by procedures including salting out with ammonium sulfate and Biogel CM-100 column chromatography. The purified enzyme appeared homogeneous on electrophoresis and ultracentrifugation, and had a molecular weight of about 21, 000. This enzyme lysed viable yeast cells in the absence of any other enzymes or additives and was tentatively named zymolyase. The optimum pH for lysis of viable yeast cells was 7.0-7.5, the optimum temperature was 35°, and the enzyme was relatively stable at pH 5-11. About 70% of its activity was lost on incubation at 50° for 5min, and all its activity was lost on incubation at 60° for 5min. Studies on the hydrolyses of β-1, 3-glucans, i.e., yeast glucan, pachyman, curdlan, laminarin, and laminaran, showed that zymolyase is an endo-β-1, 3-glucanase, which specifically releases laminaripentaose as the minimum product unit. However, it behaves like an exo-enzyme in hydrolysis of high molecular β-1, 3-glucan, which shows strong molecular aggregation like yeast glucan, releasing laminaripentaose units. Zymolyase shows much more affinity for insoluble glucan than for soluble glucan.
Effects of D-alanine and Mitomycin-C on cell morphology of Agrobacteriumtumefaciens strains F-010 (wild-type strain) and F-502 (thermoconditional morphology mutant strain) were investigated at 37° (a non-permissive temperature). D-Alanine induced following morphological changes: Normal cell form, rod shape at 27° (a permissive temperature) in both F-010 and F-502 strains, is altered by D-alanine to an abnormal cell form, ovoid (or spherical) and tadpole-like shapes, respectively, at 37°. In the presence of Mitomycin-C, individual cells of F-010 strain showed a successive morphological alteration of elongation and branching. When both D-alanine and Mitomycin-C were added to the culture of F-010 strain., form of the cells altered to a tadpole-like shape. These observations might be explained as follows: (i) D-Alanine suppresses an activity to maintain the normal cell form (rod form) in newly elongated part of the cell; (ii) Mitomycin-C is a potent inhibitor of septum formation and subsequently induces branch formation at one polar zone of a cell according to the "maximal growth rate model"; and (iii) the functional unit, which is sensitive to Mitomycin-C, in the wild-type strain, is identical to the functional unit, which is temperature-sensitive, in the mutant strain.
Saccharomyces cerevisiae requiring pantothenic acid, biotin, and inositol decreased in respiratory capacities, such as respiration rate and cytochrome contents, only by the deficiency of pantothenic acid. This decrease was effective compared to glucose repression and recovered in a short time by the addition of pantothenic acid. Simultaneously, the deficient cells were free of fully developed mitochondria and possessed only primitive envelopes with a poor inner membrane, and the mitochondrial development was induced by the addition of pantothenic acid. The development of mitochondrial membrane structure was roughly parallel to the biosynthesis of cytochromes after the addition of pantothenic acid.
Composition of the fermentation medium influenced both the rate of progesterone hydroxylation and the type of the resulting metabolite by Aspergillus niger 12Y. Dimethyl sulphoxide was a limiting factor for progesterone hydroxylation but it did not affect the types of enzymic activities. No extracellular hydroxylases catalyzing the transformation of progesterone were produced. Mycelial sporulation catalyzed the productivity of hydroxylases and/or the rate of progesterone transformation. Productivity of hydroxylases was more inducive with mycelia grown in shaken than in surface culture. Contrary to 11β-hydroxylase, the inducibility of 11α-hydroxylase was unaffected by the pH value at the time of induction. 11α-Hydroxy, l7α-hydroxy, and 21-hydroxy derivatives of progesterone induced the formation of only the corresponding hydroxylases. On the other hand, 11β-hydroxy-progesterone induced both 11β- and 21-hydroxylases. Quantities higher than 3g of induced moist mycelium and concentrations of substrate higher than 10mg in 70ml of the reaction mixture were found to be limiting factors for progesterone transformation. The in vivo 11α-hydroxylase and 11β-hydroxylase were most active within pH range of 4.0 to 6.0, while 21-hydroxylase showed a maximal activity at pH 4.0.
The effect of validamycin on the growth of Pellicularia sasakii was studied biochemically and morphologically. Validamycin significantly inhibited the rate of colony extension on water-agar, and smaller and denser colony appeared. On the other hand, its growth was not inhibited significantly when determined by the increase in the amount of protein or ribonucleic acid. Although the increase in the total length of hyphae was suppressed to some extent, the increase in the total volume of hyphae as estimated from the length and width of hyphae was not suppressed significantly. Validamycin suppressed the elongation of the primary hypha and first secondary hyphae, while the elongation of the rest of secondary hyphae was even stimulated in the presence of validamycin. Although branching of hyphae at the periphery of colony was apparently much accelerated by validamycin, there was no difference in the total number of branching points between cultures with and without validamycin. There was no difference in the cell wall components of the fungus of both cultures. It was concluded that validamycin does not inhibit the fungal growth in mass but alters the morphology of the fungus. Among other fungi tested, all belonging to Basidiomycetes were affected by this antibiotic in the same manner, while its effect on fungi belonging to other classes was diverse.