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81.
82.
本文对一类广义捕食系统生物种群生态常微模型建立几组无闭轨的充分条件,为开拓涉及该类模型制作参考类作全局制图定性的研究. 相似文献
83.
人红细胞NADH-细胞色素b5还原酶的分离纯化与鉴定黄长晖,朱忠勇,唐玉钗(南京军区福州总院全军医学检验中心实验科,福州350001)NADH细胞色素b5还原酶(Cytb5R,E.C.1.6.2.2.)是红细胞内催化高铁血红蛋白还原为血红蛋白的关键酶... 相似文献
84.
Productive infection of a cervical epithelial cell line with human immunodeficiency virus: implications for sexual transmission. 总被引:15,自引:8,他引:7
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The human cervix-derived epithelial cell line (ME180) used in this study displays a characteristics epithelial morphology, including numerous desmosomes, tonofilaments, and epidermal filaments. When T-cell lines infected with human immunodeficiency virus (HIV) are added to epithelial cultures, they rapidly adhere to the epithelial monolayer. Within a few minutes, the T cells shed numerous virions into narrow spaces formed between the epithelial cell and the adherent T cells. Virions subsequently enter the ME180 cells via large vesicles. A few days after infection, cytopathic effects and syncytium formation were observed. Infected clones of ME180 cells have remained infected for 8 months. p24 enzyme-linked immunosorbent assay and infectivity assays show that one subclone of the cell line produces virus titers equivalent to those of high-secreting HIV-infected T-cell lines. Electron microscopy reveals numerous virions budding from both the basal and apical surfaces of the epithelium. These observations suggest that cervical epithelium has the potential to serve as a site of HIV infection. 相似文献
85.
S. G. Tan J. S. F. Barker O. S. Selvaraj T. K. Mukherjee Y. F. Wong 《Biochemical genetics》1993,31(5-6):223-230
We have developed the methodologies for typing and family studies to establish the modes of inheritance of water buffalo red cell acid phosphatase (Acp), protease inhibitor (Pi), and group-specific component (Gc) on isoelectric focusing and albumin (Alb), red cell -esterase-3 (Est-3), and catalase (Cat) on polyacrylamide gel electrophoresis. Family studies showed that Pi, Gc, Alb, and Cat are coded by autosomal genes with two codominant alleles, while Est-3 is autosomal with two codominant alleles and a recessive null allele and Acp exhibits three codominant alleles.This project was funded by the Australian Centre for International Agricultural Research through Grant PN 8364 and the Malaysian programme for Intensification of Research in Priority Areas through Grant IRPA 1-07-05-057. 相似文献
86.
激光辐照选育的435与1002早籼新晶系比湘早籼7号早热,高产,米质好。醋酶同工酶多2—3条带,酶活性增强,增产潜力大。 相似文献
87.
核型似近系数的聚类分析方法 总被引:14,自引:0,他引:14
本文根据近年来核型分析所积累的大量资料,以及谭远德(1991)提出的似近分析理论,提出了核型似近系数A聚类分析方法,确定了核型计算公式,井应用于lo种淡水鱼核型似近系数聚类分析,获得了与形态分类学非常一致的结果。此外,还提出了染色体带型计算公式,从而使核型公式和校型似近系数从核型的整体结构、染色体形态结构和染色体内部结构等三个层次上,较精确地刻画了物种核型特性和物种间校型的等同性或同源性。以此核型似近系数作为分类依据所获得的物种分类结果,能真实地和客观地反映物种的自然分类模式。 相似文献
88.
Xiaofen Tan Yifan Wen Zhijun Han Xuyang Su Jing Peng Feng Chen Yadong Wang Tianming Wang Changzhong Wang Kelong Ma 《化学与生物多样性》2023,20(2):e202200089
89.
Tan Kah-Siew; Hoson Takayuki; Masuda Yoshio; Kamisaka Seiichiro 《Plant & cell physiology》1992,33(2):103-108
Irradiation of white fluorescent light (5 W m2) inhibitedthe growth of Oryza coleoptiles. Light irradiation increasedstress-relaxation parameters of coleoptile cell walls, minimumstressrelaxationtime and relaxation rate, and decreased cellwall extensibility (strain/load). Under light conditions, thecontents of ferulic and diferulic acids ester-linked to thehemicellulosic arabinose residue in cell walls increased andcorrelated with the modification of the cell wall mechanicalproperties. These results suggest that light irradiation enhancesthe formation of diferulic acid bridges in hemicelluloses, makingcell walls mechanically rigid and thus inhibits cell elongationin rice coleoptiles. Also, irrespective of coleoptile age orthe presence of light, the ratio of diferulic acid to ferulicacid was almost constant, suggesting that the rate limitingstep in the formation of diferulic acid bridges in Oryza cellwalls is in the step of feruloylation. (Received September 24, 1991; Accepted December 3, 1991) 相似文献
90.
Production of 6-Phenylacetylene Picolinic Acid from Diphenylacetylene by a Toluene-Degrading Acinetobacter Strain
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Jim C. Spain Shirley F. Nishino Bernard Witholt Loon-Seng Tan Wouter A. Duetz 《Applied microbiology》2003,69(7):4037-4042
Several strategies for using enzymes to catalyze reactions leading to the synthesis of relatively simple substituted picolinic acids have been described. The goal of the work described here was to synthesize a more complex molecule, 6-phenylacetylene picolinic acid [6-(2-phenylethynyl)pyridine-2-carboxylic acid], for use as a potential endcapping agent for aerospace polymers. We screened 139 toluene-degrading strains that use a variety of catabolic pathways for the ability to catalyze oxidative transformation of diphenylacetylene. Acinetobacter sp. strain F4 catalyzed the overall conversion of diphenylacetylene to a yellow metabolite, which was identified as a putative meta ring fission product (2-hydroxy-8-phenyl-6-oxoocta-2,4-dien-7-ynoic acid [RFP]). The activity could be sustained by addition of toluene at a flow rate determined empirically so that the transformations were sustained in spite of the fact that toluene is a competitive inhibitor of the enzymes. The overall rate of transformation was limited by the instability of RFP. The RFP was chemically converted to 6-phenylacetylene picolinic acid by treatment with ammonium hydroxide. The results show the potential for using the normal growth substrate to provide energy and to maintain induction of the enzymes involved in biotransformation during preliminary stages of biocatalyst development. 相似文献