Flavor Activity of Sulfur-containing Compounds Related to Flavor Nucleotides

Substance B, the major component, isolated from rice plant treated with probenzaole and inoculated, having anti-conidial germination activity against blast fungus, was found to be a mixture of fatty acids, including palmitic acid, linoleic acid and linolenic acid. The main compound of substance B was linolenic acid, having strong anti-conidial germination activity. It was determined as α-linolenic acid by gas chromatographic analysis. The minor components showed little or no anti-conidial germination activity.     

Biosynthesis of Cercosporin

¹³C NMR spectra were measured for 19 pyrethroids and their related compounds including allethrin, tetramethrin, resmethrin, furamethrin, phenothrin and permethrin. Complete assignment of chemical shifts was accomplished by relative spectral pattern, single-frequency off-resonance decoupling, benzene substituent effects, proton selective decoupling and use of shift reagents. The use of shift reagent was found to be especially efficient for assignment of ¹³C resonances. In the case of allethrin, the splittings of some resonance peaks were observed originating from diastereomerism.     

Studies on the Accumulation of Orotic Acid by Escherichia coli K12

The mechanism whereby Escherichia coli K12 accumulates orotic acid in culture fluid was studied. Pyrimidine compounds were incorporated effectively into cells of E. coli K12, stimulated the growth, and depressed the accumulation; while purine compounds were not so much consumed by the microorganism for its growth, and affected the accumulation to a lesser extent. On the other hand, E. coli B unable to accumulate orotic acid utilized less effectively pyrimidine compounds for its growth than strain K12.

It is supposed, therefore, that in the de novo pathway for pyrimidine synthesis in E. coli K12 the step from orotic acid to 5′-UMP is genetically depressed so that orotic acid is accumulated when pyrimidine compounds, that would cause a feedback inhibition of orotic acid synthesis upon incorporation, are not supplemented.     

Biological Activities of Fundamental,Carbohydrate Skeleton of Lipid A Containing Amide-linked 3-Hydroxytetradecanoic Acid

In the initial stage of hydrolysis, exo-ß-(l-→3)-d-glucanase from Basidiomycetes sp. QM 806 cleaved laminaran from Eisenia bicyclis with a pattern resembling an endo-hydrolase. Five kinds of intermediate gluco-oligosaccharides were separated by a combination of gel filtration and HPLC. They were shown to be 3²-O-ß-d-glucosyl-gentiobiose, 3²-O-ß-d-gentiobiosyl-gentiobiose, 3³O-ß-d-glucosyl-gentiotriose, 3⁴-ß-d-glucosyl-3²-O-gentiobiosyl-gentiobiose, and 3³-O-ß-d-gentio-biosylgentiotriose by enzymic hydrolysis and methylation analysis as well as by ¹³C NMR spectroscopy. As a result, such kinds of ß-(l → 3)-ß-(l→6)-linked oligosaccharides could be accounted for in the initial cleavage, and they were hydrolyzed ultimately to glucose, gentiobiose, and gentio-triose. It suggests that a single (1 → 3)-linkage on a block of (1 → 6)-links show some resistance to attack by this enzyme.     

An Acid- and Heat-stable β-Fructofuranosidase from Corticium rolfsii

We reported previously that an ndhB gene disruptant, ΔndhB, had the same phenotype as wild-type tobacco plants under normal growth conditions. Two other groups have reported conflicting phenotypes with each other for ndhCKJ operon disruptants. Here, we generated two transformants in which the ndhCKJ operon was disrupted, and found that new transformants had the same phenotype as ΔndhB. After illumination with visible light, all ndh disruptants had higher levels of steady-state fluorescence than wild-type controls when measured under weak light, suggesting that reduction of the plastoquinone pool in ndh disruptants was greater than that in wild-type controls. The weak light itself could not reduce the plastoquinone much, so the reduction in the plastoquinone in the mutant was due to electron donation from stromal reductants generated during illumination with the strong light. These results supported the hypothesis that NAD(P)H dehydrogenase prevents overreduction in chloroplasts and suggested that chlororespiratory oxidase did not function under low light or in the dark.     

Isolation and Biological Activity of a Peptidal Antibiotic P168

The structure of the xyloglucan synthesised in vitro by the particulate fraction of suspension-cultured soybean (Glycine max) cells from UDP-glucose and UDP-xylose is mainly composed of two kinds of oligosaccharide-building blocks, a heptasaccharide unit and a pentassaccharide unit [T. Hayashi and K. Matsuda, J. Biol Chem., 256, 11117 (1981)]. The synthesis of the pentasaccharide unit is probably the first step in the construction of oligosaccharide building blocks to elongate the ²-1,4-glucan backbone. This enzymatically synthesized xyloglucan was shown to have the same molecular size (M_w, 180,000) as the xyloglucan prepared from soybean cell walls by gel filtration on a Sepharose CL-6B column, and the same building blocks distributed among each fraction. A pulse-chase experiment indicated that the pentasaccharide unit was converted into the heptasaccharide unit. The conversion was regulated by the concentration of UDP-xylose.     

Effect of Amino Acid Supplementation to a Rice Diet on Niacin Requirement of Rats

The effect of amino acid supplementation to a rice diet on the niacin requirement of rats was studied in relation to the phenomenon of niacin or tryptophan deficiency caused by the addition of threonine or gelatin to a low casein diet. Supplementation of a mixture of all limiting amino acids other than tryptophan to a 90% rice diet stimulated the growth of rats only temporarily without additional supplementation of niacin. However, the supplementation of the same mixture of limiting amino acids to a diet containing an amino acid mixture simulating rice protein, clearly decreased the growth of rats after a temporary increase. The growth was then remarkably improved by the further addition of niacin or niacin plus tryptophan. This result supports the hypothesis that the addition of all limiting amino acids other than tryptophan, increases the use of tryptophan for protein synthesis and may lead to niacin deficiency.     

Damages Caused by Irradiation in the Presence of NaCl in Macromolecular Components of E. coli

Damages in macromolecular components and in their functions of E. coli produced by gamma irradiation in the presence of higher concentration of NaCl were determined with reference to the basic mechanism for NaCl radiosensitization. As the results, inhibitions of DNA repair, of DNA degradation, of macromolecular syntheses and of RNA species formation were found in DNA repair proficient strains. The number of radiation-induced DNA-strand breaks was not increased by the presence of 1 m NaCl during irradiation. It was suggested that inhibition of DNA repair may be of primary importance among these lesions for NaCl radiosensitization.     

Application of Plasmid to ATP Production by E. coli

A variety of immunomodulators were synthesized by combining biologically active derivatives of 1-thio-muramoyl dipeptide with 4-O-phosphono-d-glucosamine derivatives related to bacterial lipid A, and using the (succinoylamino)undecanoyl group as a spacer. Their immunoadjuvant activities in guinea-pigs were examined.     

α-l-Rhamnosidase Activity in Culture Filtrate of Corticium rolfsii Enzymic Activity at Low pH

A phosphorylation system for formation of ATP from AMP by Zymolyase-treated cells of Candida boidinii (Kloeckera sp.) No. 2201 was developed as an ATP production process. This system was shown to be an energy conversion system, from a reduced C₁ -compound to ATP through reduction of NAD⁺ and oxidative phosphorylation but not substrate level phosphorylation, together with phosphorylation of AMP to ADP.

Reaction conditions for the ATP production were optimized in respect of substrate and coenzyme concentrations, pH and temperature, osmotic pressure, and oxygen supply. Under the optimal conditions, 26 mM (13 g/liter) and 8.5 dim (4g/liter) of ATP were produced with methanol and formate as C₁ -substrate, respectively.