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51.
牛生长激素基因在马铃薯中的表达   总被引:5,自引:0,他引:5  
将牛生长激素基因cDNA 与Patatin ClassI启动子及NOS3终止子连接,构建了表达载体pPBGT. 用直接法将表达载体转入农杆菌(Agrobacterium tum efaciens) LBA4404(pRAL4404)菌株, 用此菌株转化马铃薯(Solanum tuberosum )得到再生植株. 经NPTⅡ活性检测,总DNA PCR和Southern blot证明目的基因已整合到马铃薯基因组中.RNA 点杂交和Western blot表明牛生长激素基因已在转基因马铃薯块茎中转录和表达  相似文献   
52.
四川地区幼儿和学龄前儿童的鼻部测量   总被引:2,自引:0,他引:2  
史铀  邓德华 《人类学学报》1995,14(2):151-156
本文报告1116例四川地区幼儿和学龄前儿童(2-7岁)鼻部9项指标的测量均数,性差及年龄发育特点。性差:仅鼻凹鼻底距4-6.5岁等少数指标部分年龄段男女性间出现显著性划异(男>女)。此外各项指标的绝大多数年龄段男女性间无显著性差异。年龄发育:9项测量指标中7项的生长曲线随年产长而上升,数值随年龄增大,并有1-2个发育高峰;提示鼻部发育具有阶段性;2项指标的曲线随年龄增长变化较小。4项指标男女性的曲  相似文献   
53.
Summary Postnatal rat heart cells in culture enriched with respect to muscle cells were obtained by either high density seeding or by the replating technique. [3H]Thymidine incorporation to DNA and the enzymatic pattern of cytoplasmic and lysosomal enzymes have been studied as a function of the culture’s age, of seeding density, and replating. It was shown that (a) replating maintains predominance of myocyte population for at least 2 wk in culture; (b) heavy seeding density allows homogeneous myocyte population for the 1st wk in culture; and (c) the enzyme profile of the culture may serve as an indicator for the type of cell population in culture and its state of differentiation. This study was done as partial fulfilment of the M.Sc. thesis in Biochemistry (SY). Supported by grants from The Chief Scientist, Ministry of Health, State of Israel; The Ministry of Education and Sciences, State of Niedersachssen (FRG); and The Foundation for Heart Research from Mr. and Mrs. D. Vidal-Madjar, Paris, France.  相似文献   
54.
A study was undertaken to demonstrate the safety, efficacy and value of esophageal balloon cytology in the diagnosis of esophageal lesions and as a tool in screening a high-risk patient population. The sampling was performed 110 times on 96 patients, 11 with known obstructive carcinoma of the esophagus and 85 thought to be at risk for esophageal cancer: 74 with treated or untreated cancer of the head and neck area and 11 with dysphagia or other findings requiring clarification. The method was well tolerated by the patients, and the cytologic smears were of excellent quality. Malignant or suspicious cells were found in smears from 7 to 11 patients with documented esophageal cancer and in 7 of 85 patients believed to be at risk. In the latter group there were three unsuspected recurrent cancers of the oropharyngeal region and one unsuspected carcinoma in situ of the esophagus. There were no false-suspicious or false-positive results. This noninvasive technique of esophageal cytology obviously deserves additional trials as an adjunct in the diagnosis of carcinoma of the head and neck and upper gastrointestinal tract, especially in high-risk patients.  相似文献   
55.
56.
Genetic diversity and climatic determinants of tree frogs in Israel   总被引:1,自引:0,他引:1  
Summary Allozymic variation in proteins encoded by 27 loci was analyzed electrophoretically in 218 adult specimens, mostly males, representing 8 populations, 5 central and 3 marginal, of lemon yellow treefrogs, Hyla arborea savignyi, in Israel along two transects of increasing aridity: (a) north to south and (b) west to east. The results indicate that (a) Of the 27 loci examined, 5 are monomorphic in all 8 populations; 9 are locally and weakly polymorphic; 6 are regionally and weakly polymorphic; and 7 are regionally and strongly polymorphic; (b) In the populations studied, no alternative fixations were found in any of the 27 loci, except in the Wasit population. The commonest allele predominates across all populations, except Wasit, central as well as marginal; (c) Clinal patterns associated with increasing aridity southwards and eastwards occur in polymorphism, P, heterozygosity, H, and in allele frequencies of Ldh-1, Fum, Got-1, and Sdh; (d) For habitat generalists, treefrogs have above average number of alleles per locus, A, and polymorphism, P, while the heterozygosity, H, is average. All three estimates A, P, and H exhibit wide geographic variation decreasing progressively southwards and eastwards; (e) Central populations harbor more genic variation then marginal populations; (f) Genic similarity between populations is high; (g) Significant gametic phase disequilibria were found in several tests in 2 populations; (h) P, H, and allozymic variation in several gene loci are significantly correlated and predictable by environmental variables, primarily those related to water; (i) Morphological and allozymic variations are uncorrelated.The spatial patterns and environmental correlates and predictors of genic variation in Hyla arborea savignyi in Israel suggest that (i) protein polymorphisms are largely adaptive and are molded primarily by climatic selection rather than by stochastic processes or neutrality, and (ii) the environmental variation model seems to be the best predictor of genic variation in treefrogs.  相似文献   
57.
陈威  杨颖增  陈锋  周文冠  舒凯 《植物学报》1983,54(6):779-785
植物因其固着生长的方式, 已经进化出各类特殊的机制来适应多变的外界环境。为提高自身的存活率, 植物进化出一类胁迫记忆机制, 以适应环境和保护自己。表观遗传修饰不仅能调控植物的正常生长发育, 而且参与植物对各种非生物或生物胁迫的响应。近年的研究表明, 表观遗传修饰在植物胁迫记忆调控中也发挥重要作用。例如, DNA甲基化、组蛋白甲基化及乙酰化等表观遗传修饰参与并维持特定的胁迫记忆。该文主要对表观遗传修饰介导的植物胁迫记忆最新进展进行综述, 并展望未来的重点和热点研究方向。  相似文献   
58.
Inhibition of Trichoderma reesei cellulase by sugars and solvents   总被引:2,自引:0,他引:2  
Inhibition of Trichoderma reesei cellulase by sugars (glucose, delta-gluconolactone, and cellobiose) and solvents (ethanol, butanol, and acetone) was studied using cellulose azure. Glucose, cellobiose, ethanol, and butanol were noncompetitive inhibitors, delta-gluconolactone was a mixed inhibitor, and acetone was a noncompetitive activator. Converting cellobiose to glucose reduces the effective inhibitor binding constant by 6 times and converting cellobiose to ethanol reduces it by 16 times.  相似文献   
59.
The MCA 102 sarcoma has been defined by a variety of immunologic studies as a tumor lacking intrinsic immunogenicity. Nevertheless, we have recently demonstrated the feasibility of generating therapeutically effective lymphocytes for adoptive immunotherapy of this tumor. Procedures to achieve this required in vivo priming of syngeneic mice to elicit preeffector cells followed by in vitro sensitization (IVS) with tumor cells in the presence of IL-2. By selective depletion of T cell subsets in vivo, we identified the involvement of both CD4+ (L3T4+) and CD8+ (Lyt-2+) T cells in mediating tumor regression. The CD4+ cells exerted their helper function via the secretion of IL-2 because antitumor effects abrogated by depletion of CD4+ cells could be reconstituted by exogenous IL-2. In order to elicit preeffector cells with reactivity against the MCA 102 tumor, we found that in vivo sensitization could be accomplished with either the MCA 102 or MCA 106 tumor but not with the MCA 101 or MCA 105 tumor. Analysis of specificity of tumor stimulation during IVS of MCA 102 tumor-primed preeffector cells demonstrated cross-reactivity between not only the MCA 102 and MCA 106 tumors but also the MCA 105 tumor whereas the MCA 101 tumor was ineffective. In adoptive immunotherapy, transfer of IVS cells generated from MCA 102 tumor-primed and stimulated lymph node cells was able to mediate reductions of pulmonary metastases established from the MCA 102, MCA 105, and MCA 106 tumors but not from the MCA 101 tumor. We conclude that regression of the MCA 102 tumor is probably mediated through T cell recognition of a set of common tumor-associated Ag shared by several other syngeneic tumors. Immunologically, the tumor-associated Ag are characteristically different from classical tumor-specific transplantation Ag (TSTA) because immunity to TSTA on the MCA 105 or MCA 106 tumor does not cross-react with the MCA 102 tumor. Thus, this study demonstrates that Ag other than TSTA on chemically induced tumors can serve as target molecules for T cell-mediated adoptive immunotherapy.  相似文献   
60.
姜恕 《植物生态学报》1982,6(2):163-168
一、概况联合国教科文组织(UNESCO)于1981年9月22日至10月2日在法国巴黎召开了“人和生物圈”(MAB)成立十年科学大会和MAB第七届国际协调理事会。这次大会有67个国家、375人参加,包括科学家、政策决定者和规划管理等方面的人员以及一些有关国际组织(如FAO、ICSU、IUCN等)的代表。我国派出了以中国教科文全国委员会副主任、中国“人与生物圈”国家委员会副主席秦力生为团长、中国MAB委员会秘书长阳含熙教授为副团长的六人代表团出席了会议。  相似文献   
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