低碳锰钢中周期性带状组织

用扫描电镜和电子探针研究了低碳锰钢中的周期性带状组织，结果表明，在全部研究用钢中，钢锭经热轧后均出现这种组织，其严重程度随钢的成分而异，并随坯带加工顺序而增加，带状组织与锰的显微偏析等因素有关，适当的调整碳锰以及形成模跨铁素体带的转变产物可降低带状组织的严重程度。     

利用SSR分子标记鉴定华南型黄瓜‘川绿15号’杂交种子纯度

目的 为了快速、简便和准确地鉴定华南型黄瓜‘ 川绿15号’杂交种子的纯度,方法 选用240个均匀分布在黄瓜基因组上的SSR分子标记对‘ 川绿15号’及其亲本进行多态性筛选及纯度鉴定。结果 本研究从240个黄瓜SSR分子标记筛选到2对SSR标记（Cs100和Cs109）符合父母本间呈互补带型的要求,可用于川绿15号’杂交种子的纯度鉴定。准确性验证结果显示Cs100和Cs109的分子鉴定结果与田间形态的鉴定结果一致并且均能将掺入的其他品种黄瓜种子区分开来。结论 本研究构建了以黄瓜特异性SSR分子标记Cs100和Cs109为核心引物的‘川绿15号’杂交种子纯度鉴定的技术方法,可快速、简便和准确地鉴定该品种的种子纯度,为该品种的制种和大面积推广提供技术支持。     

Effect of botulinum toxin on the choline acetyltransferase activity in salivary glands of cats

Summary The choline acetyltransferase activity of submandibular glands that had previously received a retrograde injection of botulinum toxin via their ducts was found to be markedly lower than in the untreated contralateral glands. In the parotid glands exposed to the same treatment the activity of this enzyme was less affected.This work was supported by grants from the Wellcome Foundation to S. K. K. and J. R. G., and from the Faculty of Medicine in Lund to J. E.     

The large-conductance Ca2+-activated K+ channel is essential for innate immunity

Neutrophil leukocytes have a pivotal function in innate immunity. Dogma dictates that the lethal blow is delivered to microbes by reactive oxygen species (ROS) and halogens, products of the NADPH oxidase, whose impairment causes immunodeficiency. However, recent evidence indicates that the microbes might be killed by proteases, activated by the oxidase through the generation of a hypertonic, K+-rich and alkaline environment in the phagocytic vacuole. Here we show that K+ crosses the membrane through large-conductance Ca2+-activated K+ (BK(Ca)) channels. Specific inhibitors of these channels, iberiotoxin and paxilline, blocked oxidase-induced 86Rb+ fluxes and alkalinization of the phagocytic vacuole, whereas NS1619, a BK(Ca) channel opener, enhanced both. Characteristic outwardly rectifying K+ currents, reversibly inhibited by iberiotoxin, were demonstrated in neutrophils and eosinophils and the expression of the alpha-subunit of the BK channel was confirmed by western blotting. The channels were opened by the combination of membrane depolarization and elevated Ca2+ concentration, both consequences of oxidase activity. Remarkably, microbial killing and digestion were abolished when the BK(Ca) channel was blocked, revealing an essential and unexpected function for this K+ channel in the microbicidal process.