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Mayumi Sato Tatsuo Nunoshiba Hajime Nishioka Takashi Yagi Hiraku Takebe 《Mutation research》1991,250(1-2):73-77
Sodium selenite was found to protect Escherichia coli cells against killing and mutagenic effects of N-methyl-N′-nitro-N-nitrosoguanidine (MNNG). Such protective effects were not observed when cells were treated with N-methyl-N-nitrosourea (MNU). The protection by sodium selenite was not controlled by the ada gene, which is responsible for the repair of alkylated damage in DNA. A reduction of the amount of glutathione was found when cells were treated with sodium selenite, and glutathione is known to be involved in the methylation of DNA by MNNG, not by MNU. Reduced methylation by MNNG due to the reduction of the amount of glutathione caused by abundant sodium selenite was suggested to be the mechanism of protection. 相似文献
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In the previous paper the authors reported the increase of cystine content by vitamin A in the skin of rats fed vitamin A depleted ration. It is known that both depletion of vitamin A and administration of estrogens in massive dose have the keratinizing action on the epithelium of rats. The present studies were initiated to compare the action of vitamin A with estrogens on the cystine and hydroxyproline content in the skin of rats, and the authors reported the increase of these amino acids by supplementation of this vitamin and hormone. 相似文献
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Cultural conditions for polyalcohol production by Pichia miso were examined in Waldhof type 20 liter-fermentor scale. The best result was obtained under conditions where the aeration rate was 1 volume per volume of the medium per minute with the stirring rate of 500r.p.m., (Kd=5×l0-6 [g-mol of O2/atm. min. ml.]); in 5 days incubation, Pichia miso completely dissimilated the glucose of a high concentration, 30%, and produced glycerol, D-arabitol and erythritol in a very high yield, 50% of sugar consumed. The greatest advantage compared with the shake flask culture is that the required fermentation time is shortened to half. 相似文献