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刘敬忠 《生物化学与生物物理进展》1988,15(3):238-238
根据本文第一作者提出的自抽连续离心原理,我们研制成自抽连续液/液离心分离机。 该机主要由驱动电机、转子、容器、机身及转速控制部分组成。容器上有进液槽、溢流槽、重液和轻液收集槽等。 转子外径为φ200mm,最大离心半径R=75mm,分离腔高h=36mm。 工作特点 该机适于在一段时期内分离同样样 相似文献
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刘敬忠 《生物化学与生物物理进展》1988,(3)
贵刊1987年第一期16页上的文章“多胺作为肿瘤诊断指标的可能性”一文提要中提到“本文概述近十余年国内外对多胺的研究”,但正文中通篇见不到关于国内对多胺研究的任何情况;多达30篇的参考文献也全部是外刊,无一篇是国内的。是国内从没发表过此类 相似文献
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Demonstration of Both a Photosynthetic and a Nonphotosynthetic CO(2) Requirement for NH(4) Assimilation in the Green Alga Selenastrum minutum 总被引:1,自引:1,他引:0 下载免费PDF全文
Nitrogen-limited and nitrogen-sufficient cell cultures of Selenastrum minutum (Naeg.) Collins (Chlorophyta) were used to investigate the dependence of NH4+ assimilation on exogenous CO2. N-sufficient cells were only able to assimilate NH4+ maximally in the presence of CO2 and light. Inhibition of photosynthesis with 3-(3,4-dichlorophenyl)-1,1-dimethylurea, diuron also inhibited NH4+ assimilation. These results indicate that NH4+ assimilation by N-sufficient cells exhibited a strict requirement for photosynthetic CO2 fixation. N-limited cells assimilated NH4+ both in the dark and in the light in the presence of 3-(3,4-dichlorophenyl)-1,1-dimethylurea, diuron, indicating that photosynthetic CO2 fixation was not required for NH4+ assimilation. Using CO2 removal techniques reported previously in the literature, we were unable to demonstrate CO2-dependent NH4+ assimilation in N-limited cells. However, employing more stringent CO2 removal techniques we were able to show a CO2 dependence of NH4+ assimilation in both the light and dark, which was independent of photosynthesis. The results indicate two independent CO2 requirements for NH4+ assimilation. The first is as a substrate for photosynthetic CO2 fixation, whereas the second is a nonphoto-synthetic requirement, presumably as a substrate for the anaplerotic reaction catalyzed by phosphoenolpyruvate carboxylase. 相似文献
15.
Recent efforts to define the mitochondrial genome of malaria parasites have uncovered an unexpected complexity: there are two almost totally dissimilar organellar DNA molecules. lain Wilson, Malcolm Gardner, Jean Feagin and Donald Williamson discuss the surprising possibility that Plasmodium may have, in addition to the nuclear genome, two unrelated organellar genomes, one evidently mitochondrial and the other of unknown function. 相似文献
16.
The influence of parasites on host sexual selection 总被引:7,自引:0,他引:7
Clayton DH 《Parasitology today (Personal ed.)》1991,7(12):329-334
In 1982 Hamilton and Zuk(1) proposed a provocative solution for the unexplained fact that the males of many species exhibit 'showy' traits such as brightly coloured plumage or vigorous courtship displays. They suggested that showy traits are fully expressed only by males who are resistant to parasites and that females examine such traits in order to choose resistant males as mates. Hamilton and Zuk's proposal has been the topic of extensive research and vigorous debate for nearly a decade. This article reviews the research, relevant criticisms and unanswered questions pertaining to the influence of parasites on sexual selection. 相似文献
17.
In enzymatic synthesis of cephalexin from D-alpha-phenylglycine methyl ester (PGM) and 7-amino-3-deacetoxy-cephalosporanic acid (7-ADCA) using alpha-acylamino-beta-lactam acylhydrolase from Xanthomonas citri, it was found that this enzyme catalyzes all three reactions including PGM hydrolysis, cephalexin synthesis, and cephalexin hydrolysis. Based on our experimental results, a mechanistic kinetic model for cephalexin synthesizing enzyme system having acyl-enzyme intermediate was proposed. From this kinetic model, the reaction rate equations for three reactions were derived, and the kinetic parameters were evaluated. A good agreement between the simulation results and the experimental results was found. 相似文献
18.
Three white-rot fungi, Phanerochaete chrysosporium, Polyporus tulipiferae, and Polyporus sp. A336 were grown on 100-g amounts of chopped oat straw in gassed 4.5 L (diameter 16 cm, height 23 cm) solid-state reactors for two weeks. The different gas atmospheres were regulated by (1) air diffusion through foam plugs, (2) intermittent or continuous air flow, (3) intermittent oxygen, 50 or 100% continuous oxygen flow, and (4) continuous 10% carbon dioxide in oxygen flow. The fermented straw was analyzed for total weight loss, Klason lignin loss, and enzymatic (cellulase) hydrolysis. P. chrysosporium grown on straw in continuous oxygen at 35 degrees C caused a 41% weight loss and 33.5% hydrolysis was obtained when the pretreated straw was hydrolyzed with cellulase enzyme. P. tulipiferae caused a 27% weight loss and 34.3% cellulase hydrolysis in the straw at 30 degrees C. Polyporus sp. A336 selectively degraded lignin of the straw and under intermittent oxygen resulted in an 18% weight loss and 33.6% cellulase hydrolysis at 35 degrees C. When the straw was supplemented with 10% xylose (straw basis) and was continuously gassed with 50% oxygen, Polyporus sp. A336 produced a 14.5% weight loss and 38.7% cellulase hydrolysis. Oxygen and carbon dioxide exchange rates were measured for some of these bench-scale fermentations. 相似文献
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Soybean (Glycine max L. Merrill) nodules are usually more enriched in 15N than other tissues. We show that both bacteroids and nodule cortex are considerably more enriched in 15N than nodule cytosol, with bacteroids being slightly more enriched than the cortex. Hence, 15N enrichment occurs in cells of both plant and bacterial origin. 相似文献