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91.
Excretion with urine of tyrosine and methionine metabolites as well as the activities of enzymes involved in their metabolism are correlated with the state and type of melanin synthesized in the skin. The response of tyrosine aminotransferase to melaninogenesis induction was more pronounced in animals with predominant pheomelaninogenesis, especially after tyrosine load, while that to dopachrome oxidoreductase--in animals with predominant eumelaninogenesis and after methionine load. Glutathione reductase and cystathionine-beta-synthase responded more vigorously to methionine injections, which was especially well pronounced in animals with prominent pheomelaninogenesis and in albino animals. The metabolic "block" in melanine synthesis in albino animals seems to be observed after the 5-S-cysteinyl-DOPA synthesis, whereas the initial steps of melaninogenesis in these animals are identical to pheomelanine synthesis reactions. 相似文献
92.
镉离子(Cd2+)具有强植物毒性,可抑制植物生长,甚至导致植物死亡。为了研究重金属镉对拟南芥的毒害作用,采用叶绿素荧光技术、流式细胞技术、激光共聚焦技术及半定量RT-PCR技术,检测光合参数的变化、活性氧(reactive oxygen species,ROS)的累积、自噬的发生,以及病原相关蛋白(pathogenesis-related protein,PR)基因表达的变化。实验结果显示,随着50μmol/L CdCl2处理时间的延长,ROS和Cd2+在细胞中大量积累。而在镉胁迫的初期,会观察到自噬的发生及PR基因表达的变化。说明植物受到外界Cd2+作用的初期,会通过自噬及增强PR基因表达来抵抗外界胁迫。但随着处理时间的延长,植物细胞内累积了大量的ROS和Cd2+,当植物不足以通过自噬途径抵抗胁迫时,就会导致生长受阻,最终对光合系统造成损伤。 相似文献
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Pak Valeriy V. Kwon Dae Yong Khojimatov Olim K. Pak Aleksandr V. Sagdullaev Shomansur Sh. 《International journal of peptide research and therapeutics》2021,27(3):1923-1931
International Journal of Peptide Research and Therapeutics - This study presents a simple approach in design of tripeptides as a competitive inhibitor for 3-hydroxy-3-methylglutaryl CoA reductase... 相似文献
96.
Some genetical demographic characteristics of population of Ashkhabad city were studied by direct interviewing of women aged over 18 years. The influence of urbanization on the basic genetical-demographic indices was found, the indices being essentially different from those of rural population studied elsewhere. Analysis of intensity and the structure of marriage migrations showed considerable ethnic subdivision in Ashkhabad population and stability of marriage policy in an every ethnic group. The level and structure of inbreeding as well as positive marriage assortativity are of the same order as in the Turkmen rural population. 相似文献
97.
Yu. B. Akhanaev M. N. Berim X. Jiang D. A. Kutcherov L. Luo Yu. M. Malysh S. Ya. Reznik A. Kh. Saulich V. A. Sobolev Yu. S. Tokarev A. N. Frolov L. Zhang 《Entomological Review》2013,93(7):814-818
The beet webworm, Loxostege sticticalis L., is a very dangerous polyphagous insect pest whose outbreaks periodically occur in southern Russia and northern China. The aim of our work was to describe the photoperiodic response of beet webworm populations from western (Krasnodar Territory and Rostov Province) and eastern [Buryatia and China (Hebei Province)] parts of the pest range. The insects were reared under constant photoperiods of 12–18 h and constant temperatures of 19–25°C. Incidence of diapause at different photoperiods did not show any considerable geographic differences, and the critical day length at which 50% of prepupae arrested their development was about 14–15 h in all the populations studied at experimental temperatures. The results obtained agree with the hypothesis on the existence of an area (or areas) where the pest survives during adverse periods and wherefrom it spreads when an outbreak begins (Saulich et al., 1983; Goryshin et al., 1986). Presumably, the larger part of the pest native habitats (to the north of the steppe zone) is occupied by temporary populations, incapable of surviving for long periods without an inflow of migrants from more southerly steppe regions. 相似文献
98.
Data on feeding of the bream Abramis brama, roach Rutilus rutilus, and white bream Blicca bjoerkna in Chogray Reservoir in 2010 and 2012 are presented. The main diet of bream consists of Chironomidae, and the diet of roach and white bream consists of the bivalve mollusk Dreissena polymorpha. 相似文献
99.
V A Mosin E B Krugliak T S Sterlina Iu N Korystov V V Shaposhnikova L N Kublik M Kh Levitman A V Viktorov V A Driniaev 《Antibiotiki i khimioterapii͡a》1999,44(6):16-20
Avermectins are final products in the fermentation process with Streptomyces avermitilis. They have parasitocidic activity and are used as the main substances of insectoacaronematocides. The study of the activity of the natural avermectin complex (aversectin C) and separate avermectins A1, A2, B1 and B2 in the cell culture of lymphoid leukemia P-388 showed that within the concentrations of 0.1 to 1.0 microgram/ml aversectin C inhibited the growth of the tumor cells and induced their death. The inhibition was due to blocking the cell mitosis. The cell death was accompanied by internucleosomal degradation of the DNA nuclei i.e. the death was of the apoptosis type. The sensitivity of the cells to aversectin C was directly proportional to their initial proliferative activity. As for the separate avermectins only avermectin A1 had the cytotoxic activity within the concentrations used, avermectin A2 had the cytostatic activity and avermectins B1 showed no activity under the experimental conditions. 相似文献
100.