[en] The radiosensitivity of glucose isomerase was investigated under various irradiation conditions. The inactivation of glucose isomerase irradiated in a cell-bound state was exponential, and an increase in inactivation was recongnized in an oxygenated condition. The cell-free enzyme was highly radiosensitive and had a small oxygen effect compared to that in a cell-bound state. The oxygen enhancement ratio (OER) decreased with a degree in enzyme purification. Released glucose isomerase was protected by the addition of glutathione, and the inactivation curve in nitrogen almost agreed with that in the cell. The protective effect of glutathione in oxygen decreased at higher doses because glutathione in oxygen was easily decomposed by irradiation. (author)

[en] The signals of fatty acids in the form of triglycerides were observed in the ¹³C NMR spectrum of an intact soybean seed. The major fatty acid component composition of triglycerides in a soybean seed, which includes linoleic acid, oleic acid and palmitic acid, was estimated by subtracting the spectra of authentic fatty acids from the spectrum of the intact soybean seeds. The fatty acid compositions of seeds of 11 Japanese soybean cultivars and 5 lines bred at the Asian Vegetable Research and Development Center (AVRDC) were estimated by this rapid (within 1hr for one seed) and nondestructive analytical method. (author)

[en] Glucose isomerase purified from cells of Streptomyces phaeochromogenus was irradiated in dilute solution, and the effect of γ-irradiation was investigated. The activity of the enzyme decreased exponentially with the dose under all conditions investigated. The inactivation yields (G₀-value) in neutral solution were 0.069 in air and 0.115 in nitrogen. The role of the radicals produced by water radiolysis in the inactivation of glucose isomerase was estimated by using nitrous oxide or tert-butanol as selective radical scavengers. Under these conditions, the hydroxyl radical and the hydrogen atom were found to be important in the enzyme inactivation, and the hydrated electron contributed very little. The inactivation efficiencies of the hydroxyl radical, the hydrogen atom and the hydrated electron were 0.032, 0.025 and 0.005, respectively. (author)

[en] Changes of the folate-binding protein (FBP) concentration in bovine milk after parturition were investigated. The FBP was highly purified from mature milk by affinity chromatography. The purified FBP showed a single protein band in polyacrylamide gel electrophoresis and was immunologically homogenous in double immunodiffusion. However, in two-dimensional gel electrophoresis, the FBP was separated into several spots in isoelectric focusing in the first dimension, and each spot also showed two molecular weights in SDS-gel electrophoresis in the second dimension. But these FBP molecules were immunologically identical with each other. The neuraminidase treatment obviously diminished the number of isoelectric points of the FBP. Thus, the variety of FBP molecules was at least partially due to the variability of the sialic acid content in the carbohydrate moieties. Moreover, the milk FBP showed species-specificity among mammals immunologically as well as physicochemically. (author)

[en] The absorbability of polyethylene glycol (PEG), a water-soluble nutritional marker, from the gastrointestinal tract of rat was examined using the [¹⁴C]-labeled compound ([¹⁴C]PEG) having a molecular weight of 4000. Intravenously injected [¹⁴C]PEG was readily excreted and recovered almost completely in the urine and neither hepatic nor renal uptake of the PEG was observed. Intragastically administered [¹⁴C]PEG was eliminated in the urine with an average recovery of only 0.43 +- 0.13% (Mean +- S.D., n=10) of the dose over 24 hr. From the gel column chromatographic profile of the radioactivity excreted in the urine after an oral dose, [¹⁴C]PEG was suggested to be absorbed in two forms, as an original form and as a low molecular weight component. The latter component might be the degraded product of PEG in the gastrointestinal tract. From these results it was confirmed that PEG with a molecular weight of 4000 is a satisfactory market because of its low absorbability. (author)

[en] The amounts of carboxylic acids released from electron beam irradiated polyethylene film, which can be indicators of the intensity of off-odor, were examined. The conditions for trapping acetic acid, propionic acid, n-butyric acid, and n-valeric acid from two grams of film irradiated with a dose of 20 kGy in air were established as follows; carboxylic acids volatilized at 80 deg C from irradiated film were concentrated on Tenax GC by passing nitrogen gas at a flow rate of 20 ml/min for 30 minutes. The amounts of carboxylic acids varied considerably depending upon the properties of the resin, the presence of additives, etc. Without additives, the total amounts of the acids from the film which gave the strongest off-odor was three times the total amounts of the acids from the film which gave the weakest off-odor. The addition of butylated hydroxytoluene to film reduced remarkably the formation of carboxylic acids. (author)

No abstract available

[en] The adsorption behaviour and reaction mechanism of oxamyl with acid and base saturated montmorillonites were investigated with the help of adsorption isotherms, Freundlich constants, thermodynamic parameters, IR and X-ray spectroscopy. Adsorption data were analysed, applying the linear form of the Freundlich equation. A qualitative assessment of the nature of the reaction was made with the help of these measures. Effect of temperature and different cations was also studied. The values of the equilibrium constant and standard free energy change pointed to the higher affinity of oxamyl for montmorillonite surface, and that the adsorption was in the order Na-> H- > Ca-montmorillonite. The exothermic nature of interaction indicates that the adsorption phenomenon of oxamyl on the montmorillonite surface occurred through a bonding mechanism. The data indicate the existence of protonation and/or coordination between the exchangeable cation of the montmorillonite and oxygen of the amide group of oxamyl molecule

[en] The intact cells of M. radiodurans were rendered sensitive to the action of lytic enzyme (P2-2 enzyme) by irradiation. The radiation-induced enhancement of cell lysis with P2-2 enzyme was completely prevented by the addition of t-butanol and irradiation at liquid nitrogen temperature. These results indicate that the enhancement is due to indirect action resulting from OH radicals. Cell lysis by lysozyme was enhanced only when the cells were irradiated under N₂O. The enhancement of cell lysis with lysozyme was also prevented by adding alcohols. On the other hand, when lipid components in cells were removed by extraction with n-butanol, the radiation-induced enhancement of cell lysis with P2-2 enzyme and lysozyme was not observed. From these results it is concluded that the enhancement of enzymatic cell lysis by irradiation is attributable to alteration in the lipid-rich layer of the cell wall caused by OH radicals

[en] The sucrose content in both potato tubers and sweet potato roots was considerably increased by gamma-irradiation. The maximum increase was achieved by an irradiation dose of 3 to 4 kGy for potatoes and 0.8 to 2 kGy for sweet potatoes. Cooling treatment (15°C, 2 weeks) for sweet potato roots also enhanced the sucrose content (almost 2 times) but was not additive to the irradiation treatment; the maximum sucrose content in irradiated sweet potato roots was in the range of 7 to 12% irrespective of the cooling treatment, depending on the variety of sweet potatoes. Irradiation made the sucrose content in the roots 2 to 4 times higher