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951.
952.
Publilia concava is an eastern North American membracid commonly occurring in large but spatially patchy aggregations, primarily on the host plant Solidago altissima. Like other myrmecophiles, P. concava provides sugary excretions to ants in return for the various protective, competitive or even sanitary benefits that ants provide. We developed nine microsatellite loci from P. concava. Mean per locus allele number was 6.78, and observed heterozygosities ranged from 0.03 to 0.850. One locus exhibited significant heterozygote deficit, possibly due to the presence of null alleles. These markers provide important tools for future spatial ecological studies in this model system for the study of mutualism.  相似文献   
953.
A chitinolytic enzyme from Bacillus thuringiensis subsp. aizawai has been purified and its molecular mass was estimated ca. 66 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The enzyme was able to hydrolyze chitin to chitobiosides but not carboxymethylcellulose, cellulose, pullulan, and laminarin. Optimal pH and temperature were detected at 6 and 50 degrees C, respectively. Stability, in the absence of substrate, was observed at temperatures less than 60 degrees C and pH between 5 and 8. Enzyme activity was significantly inhibited by K+ and EDTA and completely inhibited by Hg2+. Purified chitinase showed lytic activity against cell walls from six phytopathogenic fungi and inhibited the mycelial growth of both Fusarium sp. and Sclerotium rolfsii. The biocontrol efficacy of the enzyme was tested in the protection of bean seeds infested with six phytopathogenic fungi.  相似文献   
954.
This paper estimates the costs to replace fish by protein from meat, from grains and legumes, or from dairy products. We apply the World Trade Model, an input–output model of the interactions among major world regions based on comparative advantage, to analyze alternative scenarios about protein content and sources in global diets. We find that the substitution of fish by meat or dairy entails several trillion U.S. dollars of additional costs annually, corresponding to increased use of pastureland, cropland, water, and other factors of production. The price of animal products increases steeply as higher‐cost producers need to come online, yielding rents to owners of scarce resources. By contrast, the global economy adjusts at significantly lower costs to the substitution of fish by grains and legumes, but this dietary shift involves substantial modification in the mix of agricultural output and its geographic distribution. There have been few analytic studies able to associate costs and prices directly with specific combinations of dietary options. We provide a flexible economic framework for analyzing alternative scenarios about the present and future production of food. The focus on the provision of protein for the human diet, allowing for substitutions between land‐based and aquatic sources, lays the groundwork for subsequent closer examinations of the potential future contribution of aquaculture and, in a yet broader framework, the impact of the coming generation of large dams on fish habitat and freshwater ecosystems more generally.  相似文献   
955.
Professor Phillips began his involvement in the implementation of this important IAEA programme, insisting that there were advantages to be gained by using the ionizing radiation technique to sterilize human and animal tissues, based on the IAEA experience gained in the sterilization of medical products. The outcome of the implementation of the IAEA programme on radiation and tissue banking demonstrated that Professor Phillips was right in his opinion.  相似文献   
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目的:观察中成药补肾益脑丸、经舒颗粒序贯疗法治疗肾虚血瘀型月经过少84例的临床疗效。方法:采用中成药序贯疗法按照月经周期(经后期、经间期、经前期、月经期)治疗本病,经后期服用补肾益脑丸,经间期服用补肾益脑丸和经舒颗粒,经前期、月经期服用经舒颗粒,3个月为一疗程。结果:共治疗84例,总有效率92.8%。结论:本方法对肾虚血瘀型月经过少具有补肾益精、养血调经的功效。  相似文献   
959.
目的建立系统性表达人载脂蛋白A1(APOA1)基因的转基因小鼠。方法 将人APOA1基因插入系统性表达启动子下游,构建转基因表达载体,通过显微注射法建立人APOA1转基因C57BL/6J小鼠。并利用特异引物PCR法鉴定转基因小鼠的基因型,Western blot检测基因表达水平,血生化分析检测不同月龄转基因小鼠与同龄野生型小鼠的血脂指标。结果建立了2个不同表达水平的人APOA1基因的转基因小鼠品系;转入的人APOA1基因在血液、肝脏、心脏、肾脏、脾脏、血管组织中均有明显表达;血生化分析结果显示不同月龄转基因小鼠的血浆高密度脂蛋白胆固醇水平高于同龄的野生型小鼠,甘油三酯水平低于同龄野生型小鼠。结论成功建立了系统性表达人APOA1基因的转基因小鼠,为研究高血脂以及高血脂相关的心血管病提供了工具。  相似文献   
960.
目的:构建人Hepassocin的原核表达载体,可溶性表达并纯化得到高纯度的重组人Hepassocino方法:将人Hepassocin基因克隆到原核表达载体pET40b(+),转化大肠杆菌BL21(DE3),于28℃经0.1mmol/LIPTG诱导6h,表达Ds-bC-Hepassocin融合蛋白,经镍柱纯化可溶性融合蛋白,用肠激酶切除融合蛋白的DsbC-His标签,再用镍柱纯化分离酶切后的Hepassocin,通过超滤进一步纯化并浓缩,用Western blot验证纯化后的Hepassocin。结果:构建了pET40b-Hepassocin原核表达载体,经诱导表达、亲和层析和肠激酶切除融合标签,获得了相对分子质量约32000的可溶性高纯度蛋白,Western blot鉴定证实该蛋白为不含融合标签的重组人Hepassocin。结论:实现了人Hepassocin的原核可溶性表达,通过纯化获得了较高纯度的重组人Hepassocin,为制备其单克隆抗体,进一步研究其生物学功能奠定了基础。  相似文献   
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