This method is based on the theory that positive polymer ions combine stoichiometrically with negative ones in a dilute solution at a definite pH value. A definite amount of 0.005 N solution of a positive colloid like N-trimethylated glycol chitosan is added to a solution or an extract (pH ca. 7) containing alginic acid, the excess of the added positive colloid being titrated with a standard solution (0.0025 N) of a negative one such as potassium salt of polyvinyl sulfonate. The end-point of this titration is indicated by the color change of toluidinc blue or the sudden precipitation of reactants. Whenever an extract contains some protein, however, it is necessary to digest this protein by treating the extract with pepsin prior to titration. The amounts of alginic acid can be calculated from the value, which is obtained by deducting the results of several titrations from the mean-titre of blank experiments.

View full abstract

1) Despite the bacterial concentration, the survival-curves of E. coli are approximately constant at the highest concentration of 10⁷ cell/ml and at the lowest, 10² cell/ml.
2) In this case, the mass of points covers a wider range as the bacterial concentration is raised.
3) In this method, since the radiation time is shorter and there is less probability of appearance of mutants, the medium containing a concentration of 10² cell/ml seems to be most satisfactory.
4) A comparison of gamma-ray resistivity of each type of bacteria, using a medium of 10² cell/ml concentration has been made.
5) Moreover, the influence of chemical substances upon the lethal effect of gammaray on E. coli was investigated.
Acknoledgements. The author wishes to exprss his cordial thanks to Prof. T. Obara, Dept. of Agricultural Chemistry, Tokyo Univ. of Education, for his direction and generous guidance. He is also indebted to Prof. D. Ushiba, Asist. Prof. S. Sasaki, Dept. of Bacteriology, Keio Univesity, for their guidance, and to Prof. T. Asai, Dr. M. Amaha, Dept. of Agricultural Chemistry, Univ. of Tokyo, for their helpful and kind advice. Thanks are also due to Asist. Prof. H. Yamashita, Dept. of Radiology, Keio University, for his sound advice concerning radio-isotopes.

View full abstract

It is confirmed by a new method for the determination of D-glutamic acid, that Aerobacter strain A rapidly metabolizes _D-glutamic acid, while it only shows feeble metabolic activity towards L-glutamic acid when it is grown on a DL-glutamate-K₂HPO₄ medium. A specific D-glutamic oxidase is demonstrated in the cell-free extracts of Aerobacter strain A. This enzyme seems to be different from D-glutamic-aspartic oxidase obtained from Aspergillus ustus by the authors, since the former has no activity towards D-aspartic acid.

View full abstract

Aromatic amine-N-xylosides were found to produce both melanoidins and red pigments in methanol solution acidified with hydrogen chloride at 25° From N-D-xylosyl-p-aminobenzoic acid, 1-p-carboxyphenylimino-5-p-carboxyphenylamino-2-hydroxypenta-2, 4-diene hydrochloride, and from N-D-xylosylaniline, 1-phenylimino-5-phenylamino-2-hydroxypenta-2, 4-diene hydrochloride were isolated and identified respectively. And further, furfural formed from N-D-xylosyl-PABA or N-D-xylosylaniline under the same condition was identified as 2, 4-dinitrophenyl-hydrazone of which anti-form and syn-form were clearly separated by adsorption chromato-graphy with alumina.

View full abstract

The culture filtrate of the Streptomyces sp. S-580 showed strong activity in promoting the germination of rice plant seeds. The culture conditions of the strain and fractionation of the active principles from the culture filtrate were investigated. The active crude syrup (A. C. S.) obtained is effective at the dilution of 10^_??_ _??_ 10^-8 for the germination of rice plant seeds, 10^-5 _??_ 10^_??_ for barley and oats seeds.

View full abstract

A neutral crystalline substance (Factor-E), which is effective for the germination of rice plant seeds at the dilution of 10^-5_??_10^-7, was isolated from the active crude syrup extracted from the culture filtrate of Streptomyces sp. S-580. And Factor-E has been proved by hydrolysis and synthesis to be L-prolyl-L-valine anhydride (diketopiperazine), which has been proved to be the new diketopiperazine.

View full abstract

(1) Piricularia oryzae is able to utilize DL-norleucine through its conversion to α-ketocaproic acid, although, the natural occurrence of this amino acid still remains questionable. This keto acid is identified as its 2, 4-dinitro-phenylhydrazone.
(2) In the utilization of DL-alanine by P. oryzae some parts of this amino acid were utilized in the form of amino acid itself and other parts via prior conversion to pyruvic acid, but the accumulation of the present keto acid was observed only in the presence such as glucose, as it was recognized' with. of arsenite, as was already recognized with other several microorganisms.
(3) It was established that alanine is pre-ferentially utilized to a proper carbon source such as glucose, as it was recognized with glutamic acid. This may present a probable step towards solving the problem of bioche-mical mechanism of invasion of this fungus and its further growth in the host plant.

View full abstract

(1) Piricularia oryzae is able to utilize DL-isoleucine as a carbon source through its conversion to α-keto analogue, i.e., α-keto-β-methylvaleric acid. This keto acid is identified as its. 2, 4-dinitrophenylhydrazone (racemic mixture).
(2). In, the incubation of Piricularia oryzae in the medium supplemented with DL-α-aminobutyric acid, the identification of α-ketobutyric acid was unsuccessful, but the formation of α-keto-β-methylvaleric acid was recognized by the separation of its 2, 4-dinitrophenylhydrazone (racemic mixture). This fact presents direct evidence supporting the nutritional significance of aminobutyric acid as an intermediate in the biosynthetic pathway of isoleucine, in addition to the suggestive prevalency of such biosynthetic route, at least, in microorganisms.
(3) The close metabolic relationship between isoleucine and α-aminobutyric acid is suggested by the separation and identification of pyruvic acid, α-ketoglutaric acid and α-keto-β-methylvaleric acid as 2, 4-dinitrophenyl-hydrazone in either incubation added with isoleucine or α-aminobutyric acid in the presence of arsenite.
(4) The availability of formate to this fungus is indicated.
(5) The possible mechanism of the formation of these three keto acids is discussed, taking into account the paper chromato-graphic evidence obtained with the culture medium.

View full abstract

The purpose of this study is to find the optimum condition of post-hydrolysis in the wood saccharification process with concentrated sulfuric acid. The hydrolysis of the glucose-polymer which is formed by the degradation of cellulose dissolved in concentrated sulfuric acid and is soluble in dilute sulfuric acid has been measured. The hydrolysis of soluble glucose-polymer is of the first-order in sulfuric acid concentrations ranging from 5 to 40% at temperatures within the range of 87 to 130°C. The reaction constant is expressed by the following empirical equation as a function of the acidity function of sulfuric acid (C) and temperature (T°K):
k=1.61×10¹⁵exp[-1.46C-{28400/(RT)}].

View full abstract