In order to investigate the production of acid protease, the cultivation conditons were studied with black Aspergilli belonging to Kuro-Koji mold group by solid cultivation (Koji-culture).
It was observed that the production of acid-protease by A. saitoi R-3813 mut. UV-13 was markedly increased by adding an adequate amount of an inorganic nitrogen compound to the cultivation medium. Concerning the production of acid protease by adding an inorganic nitrogen compound, one hundred and eighty-four strains of Kuro-Koji mold group and eleven strains of other Aspergilli were tested.

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To examine the influence of different cultivation conditons on acid-protease production, black Aspergilli belonging to Kuro-Koji mold group which had been found to possess exceptional proteolytic activity in solid cultivation were grown under submerged condition. Furthermore, it was observed that the production of acid protease highly increased by forty to ninety per cent by adding a considerable amount of inorganic nitrogen compounds.

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Purification of the two antitumor macromolecules, A216 and A280 substances, from culture filtrates of Streptomyces is achieved by chromatography using ion-exchanged celluloses.The purified macromolecules appeared homogeneous are characterized as a protein from the chemical and biological properties by paper electrophoresis, paper chromatography and ultracentrifuge.
The simple method for approximation of molecular weight of a protein from distribution coefficient on gel filtration is proposed. The molecular weights of both macromolecules given by gel filtration are near to those given by ultracentrifugal analysis.

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N-Benzyl-(1-deoxy-1-p-toluidino)-D-fructosylamine gives extensive browning on heating in methanol or ethyl acetate especially in the present acid, and from the browned solutions N-benzyl-D-arabinonamide has been isolated. Under stream of oxygen the browning is less extensive but the yield of D-arabinonamide is increased; under nitrogen the browning is slight and unchanged diaminosugar has been recovered. In the presence of an excess of benzylamine, benzylammonium D-arabinonate has been isolated. N-Cyclohexyl-(2-cyclohexylamino-2-deoxy)-D-glucosylamine on heating with acid in stream of oxygen gives small amounts of N, N-bis (cyclohexyl)-oxaldiamide, dicyclohexyliminoglyoxal and cyclohexylammonium D-arabinonate as the oxidation products. The mechanism of the oxidative cleavages has been explained in terms of the high reducing ability of the enediamine structures which are formed by rearrangement of 1, 2-diaminosugars; in the case of N-cyclohexyl-(2-cyclohexylamino-2-deoxy)-D-glucosylamine dehydrogenation of the enediamine structure to diiminoglucosone should be involved. The findings are applied to explain the fragmentation of sugar molecules in the amino-carbonyl reactions.

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In order to study the enzymatic properties of the ε-lysine acylase in Achromobacter pestifer EA, experiments were carried out with the pure enzyme preparation. As a result of the investigation, it was found that this enzyme readily hydrolyzes ε-N-acyllysine and shows no α-amino acylase activity, and that the enzyme is not specifically activated by metal ions unlike the other acylases.

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A Bacillus accumulated 5'-nucleotides in the culture fluid during cultivation. These nucleotides consisted mainly of ribonucleoside 5'-monophosphates and of traces of nucleoside 5'-diphosphates. The composition of the accumulated nucleotides resembled that of the nucleotides of intracellular RNA. Therefore an intimate relationship between the accumulation of nucleotides and the metabolism of endogenous RNA was suggested.
The excretion of 5'-nucleotides into the culture fluid took place in parallel with the reduction of intracellular RNA, and it was presumed that the accumulated nucleotides were products of degradation of intracellular RNA.

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For the purpose of clarifying the mechanism of extracellular formation of 5'-nucleotides during cultivation of a Bacillus, which had been reported previously, attempts were made to form 5'-nucleotides by non-proliferating cells of this Bacillus.
It was found that this Bacillus rapidly degrades endogenous RNA and consequently forms 5'-nucleotides extracellularly, when the washed cells are incubated in alkaline salt or buffer solutions.
Comparison of the process of the excretion of 5'-nucleotides from washed cells with that of the accumulation of 5'-nucleotides during cultivation revealed that both were brought about by the same mechanism, i.e., the degradation of endogenous RNA.
Various factors which affect the degradation of endogenous RNA were also examined and the biological significance of this kind of RNA-degradation was discussed.

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The degradation of endogenous RNA in a Bacillus was studied as a continuation of the preceding reports
The enzyme participating in this degradation was strongly suggested to be polynucleotide phosphorylase from the findings that Mg⁺⁺ and orthophosphate were required for the degradation, orthophosphate was incorporated in parallel with the degradation of RNA and ribonucleoside 5'-diphosphates were formed as breakdown products.
The presence of polynucleotide phosphorylase was also confirmed by synthesizing polynucleotides from ribonucleoside 5'-diphosphates with an enzyme preparation from this organism.
Part of this enzyme precipitated together with ribonucleoprotein particles by a 105, 000×g centrifugation while the major proportion remained in the supernatant fluid.
The biological role of this enzyme was also discussed.

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Synthesis of hypoxanthine via some new pyrimidine derivatives is described. Convenient methods for syntheses of hypoxanthine, guanine, xanthine, 3-methylxanthine via 5-isonitrosopyrimidine compounds in two steps and some new routine synthesis of 6-hydroxy-N-alkylpurines are also described.

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Preliminary tests for pesticidal activities of some cyclic phosphorus esters derived from o-hydroxybenzyl alcohol or its analogues were undertaken. 2-Ethoxy-4H-1, 3, 2-benzodioxaphosphoran-2-one has strong insecticidal activity. Some other esters have weak or no insecticidal activity by themselves but strong synergistic action with malathion to houseflies and silkworms. Some cyclic esters show nematocidal activity and phytotoxicity.

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