[en] The effect of γ-irradiation on disinfection and storage of chick feed in kraft paper bags was investigated to prevent microbiological problems and extend storage life. In various samples obtained in different seasons, the counts of organisms were: total organisms, 2.4 x 10⁵ -- 3.9 x 10⁶; coliforms, 4.1 x 10⁴ -- 9.0 x 10⁵; osmophilic moulds, 1.1 x 10³ -- 2.2 x 10³; and fungi, 1.8 x 10⁴ -- 1.1 x 10⁵ per gram. By 0.2 Mrad irradiation, the number of total organisms decreased to 1/10 -- 1/20; coliforms decreased to 1/20 -- 1/50; osmophilic moulds decreased to below identification; and other fungi decreased to 1/10 -- 1/1000. The number of osmophilic moulds in unirradiated samples was increased during storage at high humidity conditions, whereas other microorganisms were not markedly changed. By 0.2 Mrad irradiation, the moulds were eliminated below identification but the number increased rapidly during storage. On the other hand, the occurrence of the moulds during storage was inhibited significantly in the 0.5 Mrad irradiated sample. From these results, it is concluded that mixed feed for chicks can be stored for 3 -- 4 months in the summer season after 0.5 Mrad irradiation. (author)

[en] Aqueous solutions of DNA bases, deoxynucleoside, deoxynucleotides, and mixtures of DNA base and deoxyribose were γ-irradiated in the presence of air or in nitrogen atmosphere. Each solution was prepared at a concentration of 5 x 10^-4 M. UV absorption spectra were measured directly on the test solutions, while the remaining substances and unaltered liberated bases were determined after paper chromatographic separation. The UV absorption spectra were not always depressed with decreases in remaining substances when treated with higher irradiated dose level. Adenine and cytosine appeared to be more stable in free form than in deoxynucleoside or deoxynucleotide form in nitrogen atmosphere. Ammonia and inorganic phosphate were also determined. Ammonia formation was low from thymine, thymidine and thymidine monophosphate, which have no amino group in their side chains. It will be noted that nitrogen in ring scarcely contributes to ammonia formation. Inorganic phosphate formation from nucleoside of pyrimidines was greater than from that of purines. It was observed by CD spectrometry that the conformation change of deoxycytidine by γ-irradiation was greater than that of deoxycytidine 5'-monophosphate. (author)

[en] The adsorption of uranium from sea water by various natural substances or various biological compounds was investigated. (1) It was recognized that some natural substances, Chlorella dry cells and orange peel adsorb a great quantity of uranium from sea water. (2) The experiment was carried out to screen biological compounds which have the ability to adsorb a large amount of uranium from sea water. As the result, we found that some natural high polymers, chitin, chitosan, cellulose and starch cannot adsorb uranium from sea water, while others, phosphorylated polysaccharides (chitin phosphate, chitosan phosphate and cellulose phosphate) and acid polysaccharides (alginic acid and pectic acid) adsorb large amounts. (3) The adsorption of uranium by chitin phosphate was rapid during the first 3 hours. (4) It was observed that chitosan phosphate can recover uranium (2.6 μg/g adsorbent) from natural sea water. These results show that some biological substances are potentially useful for the recovery of uranium from sea water. (author)

[en] In this study, the distribution of microorganisms in mixed feeds and fish meals, and the effect of radiation inactivation of the microorganisms were investigated. The contamination of animal feeds was remarkable, and the number of total count in the mash for chicken and other animals was from 5.3 x 10⁴ to 2.2 x 10⁶ per gram. The number of coliforms was from 5.1 x 10³ to 6.8 x 10⁵ per gram and they were mainly Enterobacter and Klebsiella. The number of osmophilic moulds was from 9.6 x 10² to 4.5 x 10⁵ per gram. In case of the mixed feeds in pellets, the total count was from 5.3 x 10³ to 1.0 x 10⁶ per gram. The contamination of fish meals was not remarkable, and only mixed fish meals were contaminated largely by faecal coliforms and others. The species of bacteria in the total count of mixed feeds were Bacilli, Micrococci, Enterobacteria and Klebsiellas, and the osmophilic moulds were Aspergilus glaucus group, A. gracilis and A. candidus. As the result, it seemed to be necessary to prevent the damage to feed stuff caused by the growth of moulds and insects and to eliminate pathogens. Osmopholic moulds are sensitive to radiation, and ere eliminated to below the identification limit by 0.2 Mrad irradation. Coliforms were more resistant to radiation, and eliminated by up to 0.8 Mrad of radiation. But some bacteria survived up to 1.5 Mrad dose. The irradiation at 0.5 Mrad seemed to be enough to reduce the total count to below 10³ per gram, and to eliminate faecal coliforms from mixed feeds. (Kako, I.)

[en] The aqueous solution of cytosine of 3.6 x 10^-2 M was irradiated with gamma -ray (60 megarad) in nitrogen-saturated glass ampules, and freeze-dried, then the residue obtained was changed to trimethylsilylacid, and this was analyzed by paper chromatography, UV spectrometry, and/or gas-liquid chromatography. Hypoxanthine, xanthine and uric acid were detected in this solution, in addition to some other compounds already known to be produced by gamma -irradiation, e.g., TMS-uracil, TMS-6-hydroxyuracil and TMS-hypoxanthine. It was presumed that these compounds were formed by the recombination of the primary radiolytic products. Uric acid formation by this mechanism was confirmed by gamma -irradiation of the mixture that contained urea, and 5- and 6-hydroxyuracil. (Kaihara, S.)

[en] Irradiated D-fructose solution exhibited marked enhancement in browning reaction with amino acid, and this effect depended on some radiolytic products of fructose. The radiolytic products formed in solution under aerated and anaerobic conditions were fractionated by column chromatography on Sephadex G-10, LH-20 and ion-exchange resin and by TLC on silica gel. The browning activity of each fraction was determined by reaction with glycine. The browning active products in the fraction were identified by GLC, GC-MS and TLC; they were: 6-deoxy-D-threo-2,5-hexodiulose, D-threo-2,5-hexodiulose, D-arabino-hexosulose and 4-deoxy-L-glycero-2,5-hexodiulose from irradiated solution under anaerobic conditions and D-threo-2,5-hexodiulose and D-arabinohexosulose from solution under aerated conditions. The browning reactions of the model compounds with glycine also indicated that D-threo-2,5-hexodiulose and 6-deoxy-D-threo-2,5-hexodiulose were more active than D-arabinohexosulose and 3-deoxy-D-erythrohexosulose. (author)

[en] Schizophyllan, an antitumor (1 → 3)-β-D-glucan that takes on a triple helical structure in aqueous solution, was irradiated with gamma-ray at doses of 0.058 to 8.4 Mrad. The molecular weight of the polysaccharide decreased as the dose of radiation increased, and the number of reducing group increased. Methylation analysis by enzymic hydrolysis with exo-β-1,3-glucanase and antitumor tests showed that the polysaccharide after irradiation at 0.058 or 0.26 Mrad had essentially the same chemical structure and antitumor activity as native schizophyllan. Treatment at 2 or 8.4 Mrad caused changes in the chemical structure and antitumor activity. The depolymerization mechanism seemed to be different from that caused by ultrasonic treatment or hydrodynamic shearing, because irradiation most readily caused changes in the chemical structure and antitumor activity. (author)