The action of DNase on HM 2 phage during DNA penetration was studied. Clostridium saccharoperbutylacetonicum, a host of HM phages was incubated in long-heated (L. H.) TYA broth at 30°C, transferred to restricted nutrition (R. N.) broth, and incubated at 30°C for certain periods. HM 2 phage (group 1) was added to the incubation mixture at an appropriate multiplicity of infection. This cell-phage mixture was treated with DNase (10 to 40μg per ml) for 7min at 30°C. When DNase was added within 4min after the addition of the phages, the infection of HM 2 phages was inhibited 25 to 35 per cent. DNase addition at later time had no effect. Free phages were never inactivated under these conditions. The uninfected host cells during DNase treatment retained the ability to form colonies. This inhibition was not due to the prevention of phage adsorption to host cells, but of phage DNA penetration.
The optimal conditions for DNase inhibition on phage infection were as follows: (1) growth of host cells in L. H. Broth (first culture) for 10 to 12hr, (2) 5 to 10 per cent inoculum of the first culture to a fresh R. N. broth, (3) growth of host cells in R. N. broth (second culture) for 2 to 4hr and (4) 0.1 to 1.0 of the multiplicity of infection.
The inhibition of HM 2 phage infection by DNase treatment was independent on the number of host cells and the environments in the reaction mixture, but dependent on the growth and physiological states of the host cells.
These phenomena were not observed with HM 3 phage (group II).

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Properties of nuclease O, a new intracellular enzyme which was partially purified from autolyzate of Asp. oryzae, ^l) are described in this paper. The purified enzyme preferentially depolymerized RNA and heat denatured DNA, but apparently did not attack native DNA. It was activated by 0.1mM Mg²⁺ or Mn²⁺, and inactive in the presence of EDTA. Optimum pH of the activity were 7.7 for DNA and 8.2 for RNA. By heat treatment (60°C, 10min at pH 6) the nuclease completely lost its activity for RNA and DNA. Optimum concentration of Tris buffer for enzymatic activity was 0.15_??_0.2M.

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Liver glutamic pyruvic transaminase (GPT) activity of rats fed on a histidine imbalanced diet was higher than those of animals fed on a histidine controlled or corrected diet. Histidase activity was not changed by varying the amount of histidine in diets from zero to 0.8% when all other amino acids were presented in a balanced composition, and the excessive amount of histidine in a low protein diet increased the activity of histidase slightly. Histidase activity increased linearly with each increase of the amount of phenylalanine in the diets from zero to 0.4%, but the further increase of phenylalanine (2%) did not increase the enzyme activity any more. On the other hand, GPT decreased by increaseing the amount of both histidine and phenylalanine in the diet along with the increase of biological value of the diet. Replacing the carbohydrate with hydrogenated coconuts oil did not alter the activity of histidase, and increased the activity of GPT.

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Various sugars and glucosides inhibited both ascorbate-activated and non-activated plant myrosinases at much higher concentrations than those of the substrate. Among these, glucose and salicin were confirmed to be competitive inhibitors. The resemblance of myrosinase to β-glucosidase was pointed out from these results. The Ki values for them remained unchanged after the activation of the enzyme by L-ascorbate, whereas the Km value for the substrate increased. Glucose had no influence on the binding of ascorbate to the enzyme. Pigman's model for β-glucosidase can be satisfactorily applied to yield an explanation of these experimental results.

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β-Glucosidase activity of mustard myrosinase was confirmed using p-nitrophenyl β-glucoside (p-NPG) as the substrate. p-NPG hydrolysis was not accelerated by 10^-3M ascorbate but was inhibited competitively by its higher concentrations. This result forms a distinct contrast with the activating effect of ascorbate in enzymatic sinigrin hydrolysis. The previously noticed feature of the ascorbate effect on the enzyme that the Km value for sinigrin hydrolysis increased after activation is explainable by the fact that ascorbate was a competitive inhibitor as well as a specific activator. A schematic model interpreting the interaction of ascorbate with the enzyme is proposed.

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In the research on the plant growth regulators produced by phytopathogenic fungi, two active metabolites, sclerotinin A and B, in addition to sclerin have been isolated from the culture filtrate of S. sclerotiorum. Sclerotinin A and B have been shown to be 3, 6, 8-tri-hydroxy-3, 4, 5, 7-tetramethyl-3, 4-dihydroisocoumarin and 3, 6, 8-trihydroxy-3, 5, 7-trimethyl-3, 4-dihydroisocoumarin, respectively.

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Changes in the metabolism in vivo of amino acids with the lapse of time after feeding a diet were investigated by measuring the incorporation of ¹⁴C into some body components one hour after injection with ¹⁴C-amino acid mixture.
The incorporation of ¹⁴C into protein in the liver and carcass was rather constant, but that into blood sugar, liver glycogen, and lipids in the liver and carcass showed a change with the lapse of time after feeding a 25% casein diet or a protein-free diet. The incorporation of ¹⁴C into liver glycogen was stimulated shortly after feeding, but it was reduced at 7hr, when a large amount of glycogen was still in the liver. On the contrary, the specific activity of blood sugar increased with the lapse of time after feeding. The conversion of ¹⁴C-amino acids into lipids in the liver and carcass was stimulated shortly after feeding.
The incorporation of ¹⁴C into protein was higher in the rats fed the protein-free diet than in those fed the 25% casein diet, and the higher incorporation was partly counterbalanced by the lower incorporation of ¹⁴C into lipids and glycogen in the rats fed the protein-free diet.

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Growth of a baker's yeast was inhibited at definite cell concentrations when cells were incubated in a glucose medium containing L-methionine under semi-aerobic conditions. A little or no significant growth inhibition by methionine was observed when the cells were cultured under very aerobic or anaerobic conditions. Under semi-aerobic conditions glucose was first metabolized by the fermentative process yielding almost theoretical amounts of ethanol. The secondary growth occurred at the expense of accumulated ethanol by oxidative metabolism. Methionine inhibited the utilization of ethanol as well as the secondary growth without affecting glucose fermentation and the primary growth. Manometric experiments revealed that cells grown in the absence of methionine showed vigorous respiratory activities towards ethanol substrate. This oxidation was not affected by the addition of methionine. On the contrary, cells grown in the presence of methionine exhibited only feeble oxidative activities with ethanol. Therefore, methionine inhibits the formation of respiratory enzymes responsible for the oxidation of ethanol. The possible mechanism of this inhibition was discussed.

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The production of lipoprotein lipases by Pseudomonas sp. M-12-33 was improved by an increased aeration. Glucose stimulated the growth of the bacterium but reduced the enzyme production in Bouillon medium. Olive oil remarkably increased the production of lipoprotein lipases but the effect was cancelled by calcium carbonate. Stearic and palmitic acids were as effective as olive oil, but capric and caprylic acids inhibited the enzyme production. Urea was proved to be very effective as a nitrogen source for the production of lipoprotein lipases.

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The lipoprotein lipase production by Mucor species was tested and Mucor javanicus IAM 6108 was selected as the best producer of the enzyme in shaking culture. Then the effect of culture conditions was examined. Corn steep liquor was a good nitrogen source, while the addition of urea markedly inhibited the enzyme production. Each of glucose, dextrin and soluble starch was equally effective as the carbon source. A high concentration of glucose (3.0%) resulted inhibitory effect. Optimum temperature was 26°C and a good aeration was required. Lipoprotein lipase production was increased remarkably (by 5 to 8 times) by the addition of “soybean yuto” (1.0%), the effective component of which was demonstrated to be phosphatidyl inositol. Lipoprotein lipase activity was assayed by the estimation of free fatty acids according to the method of Dole with some modifications in which “plasma activated” olive oil emulsion was used as substrate.

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The effects of biotin and oleic acid concentrations in the media on the utilization and the distribution of oleic acid-U-¹⁴C were investigated using an oleic acid-requiring mutant of Brevibacterium thiogenitalis No. 653.
Oleic acid in the media was rapidly taken up by the cells and its uptake-rate was enhanced by biotin. Oleic acid uptaken was incorporated into a sugar lipid and phospholipid fractions and some amounts of these lipids were excreted to the media.
The distribution of oleic acid-U-¹⁴C in the cellular lipid fractions was changed by biotin or oleic acid concentration in the media. About 40% carbon of oleic acid which was added to the media was incorporated into the sugar lipid fraction.

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Sclerone, mp 138_??_140°C, C₁₀H₁₀O₃ was isolated from the culture filtrate of Sclerotinia sclerotiorum. This is optically active, [α]²⁰_D-30°, and gave 1, 5-naphthalenediol on pyrolysis. Oxidation with MnO₂ yielded juglone. From the chemical and physical evidences, the structure was determined to be 4, 5-dihydroxy-(4S)-3, 4-dihydro-1(2H)-naphthalenone.

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