Urocanic Acid,Produced by Sporogenous Bacteria

On the screening of microorganisms which accumulate ultra violet light absorbing substances, some sporogenous bacteria were selected as powerful strains for production of a crystalline substance having a maximum absorption at 267.5 m_μ (pH 6.0 in water). These strains were microbiologically examined and named B. subtilis var. thermophilus. Submerged fermentation was carried out for 48 hrs at 37°C in glucose bouillon medium and the isolation of substance was performed by absorption to active carbon and elution with ammonia water.

On the basis of chemical studies of this crystal, it was identified as urocanic acid.     

Mutant of Escherichia coli Tolerant to the Lysis Induced by Cephalexin

2,3-Diaminopropionate ammonia-lyase (DAPAL), which catalyzes α,β-elimination of 2,3-diaminopropionate regardless of its stereochemistry, was purified from Salmonella typhimurium. We cloned the Escherichia coli ygeX gene encoding a putative DAPAL and purified the gene product to homogeneity. The protein obtained contained pyridoxal 5′-phosphate and was composed of two identical subunits with a calculated molecular weight of 43,327. It catalyzed the α,β-elimination of both D- and L-2,3-diaminopropionate. The results confirmed that ygeX encoded DAPAL. The enzyme acted on D-serine, but its catalytic efficiency was only 0.5% that with D-2,3-diaminopropionate. The enzymologic properties of E. coli DAPAL resembled those of Salmonella DAPAL, except that L-serine, D- and L-β-Cl-alanine were inert as substrates of the enzyme from E. coli. DAPAL had significant sequence similarity with the catalytic domain of L-threonine dehydratase, which is a member of the fold-type II group of pyridoxal phosphate enzymes, together with D-serine dehydratase and mammalian serine racemase.     

Studies on Plant Growth Substances

1-Naphthoic acid derivatives substituted with chlorine, bromine, methyl or nitro groups at various positions of the ring were assayed for their activities in the pea straight-growth and the callus formation tests. Their growth activities are discussed from two points of view, i.e. the spatial structure hypothesis of Veldstra and the ortho reaction hypothesis advanced for benzoic acid derivatives proposed by Hansch and Muir. It appears that a combination of these two views are appropriate for the present authors’ results.     

Interaction of the β-Transglycosylase of Trichoderma longibrachiatum with Cellulose

The effects of cellulose on the production and stimulation of β-transglycosylase were studied. The β-transglycosylase of Trichoderma longibrachiatum was produced specifically in the presence of cellulose in Czapeck-Dox medium containing sucrose as a sole carbon source. The enzyme activity was stimulated by the addition of cellulose in the reaction mixture, where the transfer reaction product (a water-insoluble glucan) was apparently synthesized on the surface of the added cellulose fibers.

The hyphal wall fraction of the fungus had the same stimulatory effect on β-transglycosylase as the cellulose fibers. A cellulose-like material in this fraction was found by partial acid hydrolysis and gas chromatography. Cellotriose was the smallest substrate effective for the synthesis of a water-insoluble glucan in the presence of cellulose by the β-transglycosylase, though a significant amount of glucan could not be synthesized without the addition of cellulose.     

Evaluation and Elimination of the Interference by Starch in the Biuret Determination of Wheat Protein

In the biuret determination of wheat protein, starch, color substances and lipids extractable with an alkaline solution such as biuret reagent were found to interfere with the biuret method. Comparative evaluation of their effects revealed that starch, a major component of wheat, has the most significant effect on the biuret method. In the presence of starch, the correlation between Kjeldahl protein and the optical density of biuret was poor.

It was found that several organic solvents effectively retarded solubilization of wheat starch in the biuret reaction mixture. By treatment of the wheat samples with these solvents prior to the biuret procedure, the effect of starch was completely eliminated and the optical density of biuret became closely correlated with Kjeldahl protein.     

A Direct Synthesis of Unsaturated Uracil Nucleosides from Silylated Uracil and Triacetylglucal

A kinetic analysis of splitting oligomeric substrates by poly(β-D-mannuronate)lyases (alginate lyases I, SP1 and SP2) from a marine mollusk was done. Monomer and oligomers of mannuronate and guluronate were prepared by hydrolyzing poly β-1,4-D-mannuronate and poly α-1,4-L-guluronate from alginate with H₂SO₄, respectively, and thereafter by gel filtration on a Bio-Gel P-2 column. Alginate lyases I apparently did not act on the trimer of mannuronate but did on the tetramer or those longer than that, indicating the increased k_cad/K_m with increasing polymerization degree. The kinetic analyses suggest that the size of the subsite structure of the enzymes is most likely to be able to bind the linear pentamer of mannuronate units.     

Hydrocarbon Repellents Isolated from Tribolium castaneum and T. confusum (Coleoptera: Tenebrionidae)

Seven unsaturated hydrocarbons were isolated from the volatiles of two species of flour beetles, Tribolium castaneum and T. confusum, and identified as 1-pentadecene, 1-heptadecene, 1,8-heptadecadiene, 1-tetradecene, 1-hexadecene, 1,6-pentadecadiene and heptadecatriene by GLC, GLC–MS, NMR, IR and micro-ozonolysis. This is the first report of the presence of these compounds in red flour beetles, and the last four compounds are also reported for the first time in confused flour beetles. These compounds are strong repellents for the same species or each other. The roles of these compounds are discussed.     

Study on the Optical Rotatory Dispersion of Di-Peptides and its Application to the Recognition of Di-Peptides from Higher Peptides and Amino Acids

During the cource of the investigation of ribotidation of purine and pyrimidine bases by Brevibacterium ammoniagenes ATCC 6872, it was found that a large amount of uridine 5′-monophosphate (UMP) was accumulated in the culture broth when the organism was incubated in a medium containing uracil or orotic acid. The yields of UMP were 83% (4.8 mg/ml) from uracil and 100% (4.3 mg/ml) from orotic acid when each substrate was added at the concentration of 2 mg/ml.

Addition of 6-azauracil or 5-hydroxyuracil to the culture of the organism during cultivation led to the accumulation of both orotidine 5′-monophosphate (OMP) and UMP. The accumulation of OMP seemed to be due to the inhibition of OMP decarboxylase (E. C. 4.1.1.23) by the ribotide formed from each base. The OMP accumulation was enhanced by the addition of orotic acid in addition to 6-azauracil. When 6-azauracil was added to the medium before inoculation, UMP was predominantly accumulated, and when it was added after one day incubation, OMP was predominantly accumulated. A largest accumulation (3.6 mg/ml) of OMP was obtained when 6-azauracil was added on the 1st day and orotic acid was added on the 3rd day.

UMP and OMP accumulated in the medium were isolated from the cultured broth and identified by usual methods.     

Microbial Conversion of Petro-sulfur Compounds

For the purpose of proving possibility of desulfurization from petroleum oil by microbial procedures, first approach was made to obtaining microorganisms capable of converting petro-sulfur compounds. Dibenzothiophene was used in this study as a model of the sulfur compounds in heavy oil.

Six strains of microorganisms were isolated with dibenzothiophene from various soils. These strains produced organic acid compounds containing sulfur from dibenzothiophene. As a result of the taxonomic studies, three of the strains were found to be new species belonging to the Genus Pseudomonas, so the authors proposed to assign the names, Pseudomonas abikonensis nov. sp. to one strain, and Pseudomonas jianii nov. sp. to the other two strains.     

Utilization of Soybean Products in Fish Paste Products

Large amounts of food-grade soybean products are consumed in fish product industries in Japan. To clarify the properties of soybean products desirable for fish processing, the kamaboko added with soybean products were evaluated by both sensory testing and instrumental measurements. The correlation between the suitability of soybean products for kamaboko and the basic chemical and functional properties of the soybean products was discussed. It was found that the “hardness” of the kamaboko added with soybean products correlated highly with the degree of denaturation of soy protein and with the amount of nitrogen of soybean products not dispersible in 3% sodium chloride aqueous solution.

It was also estimated that the textural properties of kamaboko added with soybean products could not be deduced from the textural properties of heat-coagulated gels of the corresponding soybean products.