The occurrence of Ls-allo-isocitric acid in nature, as a new fugal product, was first found in the culture medium of Pen. purpurogenum Stoll var. rubri-sclerotium Thom. No. 1148. The acid was obtained as its γ-lactone in a crystalline form. Some chemical and physical characters were described. The acid was the only one detectable acid accumulated by this fungus in the given condition, and the yield of the acid by weight exceeded about 70% of the consumed glucose.
1. Further purification of the enzyme responsible for the oxidation of D-glutamic and D-aspartic acids was carried out and an enzyme of 90% purity was obtained. 2. This enzyme could oxidize D-glutamic and D-aspartic acids but was incapable of oxidizing DL-α-aminoadipic and α-aminomalonic acids. The name D-glutamic-aspartic oxidase was designated for this enzyme instead of its previous name, D-monoaminodicarboxylic acid oxidase. 3. The prosthetic group of the enzyme was proved to be FAD. 4. No metallic component was detectable in the enzyme. 5. Some studies concerning the mechanisms of the inhibitory action of KCN are also presented here.
Auxotrophic mutants of Streptomyces griseoflavus have been isolated by the following method. After irradiating conidiospores with ultraviolet light, the survivors, equivalent to 0.1 to 1% of the conidia irradiated, were incubated on complete agar for a week and, to the newly arrived conidia, filtration technique was applied in order to concentrate the growth factor-requiring mutants. They were then recovered among the colonies on a complete medium with the aid of the replica plating method. Preincubation prior to filtration proved important, because the frequency of mutants recovered among colonies on the complete medium was raised from 0.1 to 1% by this process. The mutants required the following growth factors: methionine, arginine, cystine, tryptophan, nicotinic acid, glycine or serine, adenine, xanthine, hypoxanthine or uric acid, and glutamic acid or aspartic acid.
In contrast to several species of Streptomyces which revealed exponential survival curves by X-ray inactivation tests, Str. Griseoflavus and auxotrophic mutants of the strain gave apparently "two-hit" curves. On the ground of the interrelation between radiokinetic and biological findings, a proposal that the conidium of Str. Griseoflavus comprises a bipartite or diploid nucleus in each cell was presented.
1) Pentose fermentation by various lactic acid bacteria can be classified into the following two types : a) Formula (I) which proceeds according to the Fred-Peterson-Anderson system, and b) formula (III) which supposedly involves a new pathway of pentose metabolism. Almost all of the examined organisms metabolized various pentoses according to either formula (I) or (III) exclusively. But, some exceptional strains fermented different pentoses by different schemes. For example, Leuconostoc mesenteroides B07 fermented various pentoses only according to formula (I) and L. thermophilus T1 according to formula (III) exclusively. Whereas, L. thermophilus II was able to ferment L-arabinose by formula (I) and D-xylose by formula (III). 2) From comparative study of pentose fermentation in the presence and absence of carbonate and an isotopic experiment for incorporation of carbonate into lactate, it was concluded that carbonate fixation reaction is not involved in lactate formation from pentoses. 3) Anaerobically, the cells of S. faecalis grown in a L-arabinose medium produced lactic acid from L-arabinose in a yield of 95% by weight of consumed sugar, and likewise those of L. thermophilus T1 grown in D-xylose medium converted 93% of consumed D-xylose to lactic acid. In both cases no formate and CO2 were formed. As a consequence of these experiments, we proposed a new formula (II) as an alternative scheme of (III). 4) From the analysis of yields of lactate from glucose, pentose and sedoheptulose, no noticeable difference in yield among these fermentations was observed. Consequently, we have concluded that so-called pentose phosphate pathway may have no inconsistency for accounting for the pentose metabolizing system of S. faecalis. This hypothesis, however, can not be applied for such a strain like L. thermophilus T1 which unable to ferment sedoheptulose.
By cultivating a green strain and a yellow mutant in media lacking copper and/or halogen ions, the responsibility of these ions upon the development of green color of conidia was studied. 1. The green strain took up a larger amount of copper into its mycelia when it was cultivated in a medium containing copper ion. 2. The yellow mutant could take up a sufficient amount of copper to produce green conidia only when halogen ion was supplemented together with copper ion. 3. By a comparison test with other color mutants, the yellow mutant was proved to be extremely poor in the ability of copper uptake. On the ground of these bases, it was concluded that the development of green color of conidia in these strains is closely related with the ability of copper uptake and that halogen ion can restore the genetic defect in the copper uptake system.
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