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131.
干旱和湿润生境下辽东栎群体遗传结构及其适应意义的初步研究 总被引:3,自引:0,他引:3
应用同工酶分析方法,测定北京市东灵山区两个分别代表干旱和湿润生境的辽东栋(QuercusliaotungensisKoiz.)群体的遗传结构。共分析统计了13 个酶系统30 个位点。结果表明:辽东栎群体内部存在丰富的遗传变异(多态位点百分率为86.6% ,等位基因平均数为2.25)。两群体遗传结构的相似性程度很高(D= 0.029, GST= 0.048);但在个别位点上仍存在较大差异,这些差异的产生可能与对小生境的适应有关。对不同年龄段的初步分析结果显示,基因频率的动态变化可能有其适应意义 相似文献
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133.
Hae-Chul Park Kyung-Jun Lim Jin-Seo Park Yong-Hyun Lee Tae-Lin Huh 《Biotechnology Techniques》1995,9(1):31-34
Summary A strain of Alcaligenes eutrophus producing poly--hydroxybutyric acid was successfully transformed by the electroporation. The plasmid used was a broad host range plasmid pKT230 conferring kanamycin resistance. The optimum yield of transformant was 0.8×102/g DNA when 50 l competent cells at 1010/ml were pulsed by 11.5 kV/cm for 5 ms with 1 g DNA. Plasmid DNA in the A. eutrophus transformant was stably maintained as a monomeric structure. 相似文献
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135.
在海拔3700m高原选择50名男性青年的体重、立定跳远、引体向上、仰卧起坐、60m和2000m跑速度6项指标进行高原移居青年体制综合评价方法的研究。通过用百分位法制定各项指标评分标准,以各项指标评分相加作为体质总分,并用各项指标的简单相关系数与多元逐步回归方程的标准化偏回归系数的乘积(贡献率)分配“权重”,建立综合评价总分的计算式:Y=0.05X1+0.16(X4+X6)+0.21(X2+X3+X 相似文献
136.
Characterization of translation products of the polyadenylated RNA of free and membrane-bound polyribosomes of rat forebrain. 总被引:4,自引:2,他引:2 下载免费PDF全文
Poly(A)+ RNA (polyadenylated RNA) isolated from membrane-bound and free polyribosomes was translated in reticulocyte lysates, and the products were analysed by two-dimensional gel electrophoresis. Several translation products were specific to membrane-bound polyribosomal mRNA, including polypeptides of 47kDa, 35kDa and 21 kDa, whereas others (e.g. of 37 kDa, 17 kDa and 14 kDa) were specific to free polyribosomal mRNA. Although many products were common to both mRNA species, cross-contamination could be ruled out on the basis of the presence of these and other specific products. The common products included a 68 kDa microtubule-associated protein, tubulin, actin, the brain form of creatine kinase, neuron-specific enolase and protein 14-3-3 and calmodulin, all of which were identified on the basis of two-dimensional gel and peptide analyses. The 35 kDa protein product of membrane-specific mRNA was co-translationally processed in vitro by microsomal membranes, resulting in its cleavage to 33 kDa (and partial glycosylation). The 33 kDa processed protein (but not the 35 kDa precursor) was integrated into both dog pancreas and rat brain microsomal membranes. The occurrence of the enzymes and calmodulin as products of membrane-bound polyribosomal mRNA is discussed in the light of their presence on rat brain synaptic plasma membranes [Lim, Hall, Leung, Mahadevan & Whatley (1983) J. Neurochem. 41, 1177-1182] and their existence in a specific component of axonal flow. It is suggested that some of these translation products of the rough endoplasmic reticulum may represent proteins destined for the plasma membrane. However, the identity and location of the 35 kDa membrane-specific product (or its processed form) still remain unestablished. 相似文献
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138.
A collection of dicroceolid flukes from rats, squirrels and Tupaia in Malaysia is found to be morphologically heterogeneous. Cluster analysis on the basis of three selected body ratios distinguishes two major types comprising highly diverse Skrjabinus from rats, and homogenous Zonorchis from callosciurid squirrels. Tupaia harbours flukes of both genera. Analysis of variance of flukes from rats, demonstrates marked uniformity among worms within individual hosts. Possible effects of allometric growth are investigated by plotting each chosen dimension against body length for the two major groups of worms. Prominent changes are noted only in the relative size of testis in Skrjabinus from rats. Patterns of morphology are discussed in relation to host ecology and distribution. 相似文献
139.
Neisseria gonorrhoeae was identified by the Phadebact gonococcus test, a rapid slide coagglutination technique, and the results obtained were compared with those obtained by conventional methods (Gram stain morphology, oxidase reaction, and carbohydrate utilization tests) for the confirmatory identification of gonococci. Of 308 clinical isolates examined, the coagglutination procedure correctly identified 97.8% of the isolates tested as N. gonorrhoeae and 93.9% of other bacteria as not N. gonorrhoeae. The coagglutination procedure also identified 29 laboratory strains correctly as not N. gonorrhoeae. The slide coagglutination test is easy to perform and offers a valuable alternative to other techniques for the confirmatory identification of N. gonorrhoeae. 相似文献
140.
The relationship of the oestrogen and progestin receptors in the abnormal uterus of the adult anovulatory rat. Effects of neonatal treatment with testosterone propionate or clomiphene citrate. 总被引:1,自引:1,他引:0 下载免费PDF全文
The neonatal administration of testosterone propionate to Wistar rats resulted in anovulatory adults in persistent vaginal oestrus. Clomiphene citrate had a similar effect. In both groups of adults, hyperplasia of the uterine epithelium and occasional metaplasia was observed. The uterine nuclear and cytosol oestrogen and progestin receptors of these anovulatory rats were found to have affinities for their respective ligands similar to those of normal females. The nuclear oestrogen receptor comprised occupied and unoccupied components, as in normal females. The content of the nuclear oestrogen receptor was comparable with that of females in the late dioestrous or pro-oestrous phase. This content was higher in the clomiphene-treated group. Despite the relatively high nuclear oestrogen receptor content the content of progestin receptors, a putative index of the oestrogenic response, was lower in the treated rats than in normal adult females throughout the cycle. Administration of oestradiol to both treatment groups resulted in depletion of cytosol oestrogen receptor content 1 h later, which, however, was not reflected by an increase in the content of nuclear oestrogen receptors. There was no measurable increase in progesterone receptor content in treated rats after daily administration of oestrogen (5 microgram/rat) for 3 days. These changes in sex-hormone-receptor interactions involving an impairment of the normal oestrogenic response may be associated with the abnormal differentiation of the uterus in these sterile, anovulatory animals. 相似文献