Development of simple sequence repeat (SSR) markers for the assessment of gene flow between sea beet (Beta vulgaris ssp. maritima) populations

Molecular markers can be used to estimate gene flow indirectly by monitoring the relative frequency of alleles in adjacent populations. Sea beet (Beta vulgaris ssp. maritima) is a wild plant species found along the coastlines of many European countries and is closely related to cultivated beets. A set of six simple sequence repeat (SSR) markers that are polymorphic in UK populations have been developed for sea beet to assess the problems of indirect measurement of gene flow in these populations.     

乌头类双酯型生物碱水解产物-苯甲酸的含量测定研究

目的:建立RP-HPLC测定乌头类双酯型生物碱水解产物苯甲酸含量的方法.方法:色谱柱:Waters C18(150×4.6 mm),流动相:甲醇-0.02 mol/L乙酸铵溶液(5∶95),检测波长:230 nm,流速:1.0 ml/min,柱温:30℃.结果:苯甲酸在0.432～3.888μg(r=0.9999)之间呈线性关系,苯甲酸加样回收率为98.62%(RSD=1.89%).结论:该方法简便、稳定、准确,可做为乌头类双酯型生物碱水解产物苯甲酸含量测定的方法.     

中国栉眼蚤属两新亚种记述(蚤目:多毛蚤科)

根据１９８８年以来,人采自浙江省景宁,永嘉等县的标本,记述了栉眼蚤属两新亚各,即台湾栉眼蚤浙江亚种Ｃｔｅｎｏｐｈｔｈａｌｍｕｓ（Ｓｉｎｏｃｔｅｎｏｐｈｔｈａｌｍｕｓ）ｔａｉｗａｎｕｓｚｈｅｊｉａｎｇｅｎｓｉｓＬｕｅｔＱｉｕ,ｓｓｐ．ｎｏｖ和短突栉眼蚤永嘉亚种Ｃｔｅｎｏｐｈｔｈａｌｍｕｓ（Ｓｉｎｏｃｔｅｎｏｐｈｔｈａｌｍｕｓ）ｂｒｅｖｉｐｒｏｊｉｃｉｅｎｓｙｏｎｇｊｉａｅｎｓｉｓ,Ｌｕ,Ｚｈａｎｇ,     

一种研究和鉴别悬浮培养红豆杉细胞凋亡与坏死的新方法

将在动物细胞凋亡研究中应用的Hoechst-PI双重荧光染色法与琥珀酸脱氢酶(SDH)染色法相结合,建立了一种更加完善的、能同时鉴别和研究悬浮培养的植物细胞凋亡及坏死的新方法——Hoechst-PI-SDH三重染色法(H-P-S法)。该方法可直接用于红豆杉悬浮培养细胞,无需对细胞进行去壁、固定及切片等其它方法所必需的步骤,在荧光显微镜下可鉴别活细胞、死细胞及凋亡细胞,并可同时观测细胞凋亡的全部过程。该方法简单、快速、准确,而且克服了因细胞膜通透性差异引起的对死、活细胞判断的困难,可在植物细胞凋亡的研究中广泛应用。     

Development of simple sequence repeat (SSR) markers for the assessment of gene flow and genetic diversity in pigeonpea (Cajanus cajan)

Pigeonpea (Cajanus cajan) is an important subsistence crop in India where traditional landraces and improved hybrids are grown alongside each other. Gene flow may result in genetic erosion of these landraces and their wild relatives, whilst transgene escape from future genetically engineered varieties is another potential hazard. To assess the impact of these factors gene flow needs to be measured. A set of 10 simple sequence repeat markers have been developed, which exhibit polymorphism across a range of pigeonpea varieties. Use of these markers also offers an efficient system for the assessment of genetic diversity within populations of pigeonpea.     

Campylobacter jejuni adenosine triphosphate phosphoribosyltransferase is an active hexamer that is allosterically controlled by the twisting of a regulatory tail

Adenosine triphosphate phosphoribosyltransferase (ATP‐PRT) catalyzes the first committed step of the histidine biosynthesis in plants and microorganisms. Here, we present the functional and structural characterization of the ATP‐PRT from the pathogenic ε‐proteobacteria Campylobacter jejuni (CjeATP‐PRT). This enzyme is a member of the long form (HisG_L) ATP‐PRT and is allosterically inhibited by histidine, which binds to a remote regulatory domain, and competitively inhibited by AMP. In the crystalline form, CjeATP‐PRT was found to adopt two distinctly different hexameric conformations, with an open homohexameric structure observed in the presence of substrate ATP, and a more compact closed form present when inhibitor histidine is bound. CjeATP‐PRT was observed to adopt only a hexameric quaternary structure in solution, contradicting previous hypotheses favoring an allosteric mechanism driven by an oligomer equilibrium. Instead, this study supports the conclusion that the ATP‐PRT long form hexamer is the active species; the tightening of this structure in response to remote histidine binding results in an inhibited enzyme.     

胆汁致消化道黏膜损伤机制的研究进展

胆汁是由肝细胞分泌的胆道内的消化液,为等渗溶液,主要成分包括胆盐、胆汁酸、胆红素、还原型谷胱甘肽及其结合物、氧化型谷胱甘肽等。在消化期,胆汁可由肝脏和胆囊大量排到十二指肠,将脂肪乳化成微滴以利于消化;还能促进脂肪酸及脂溶性维生素的吸收。生理状态下胆汁不会反流入胃及食管,也不会损伤肠道。病理状态下胆汁会反流入胃甚至反流到食管损伤胃及食管黏膜,在一些情况下胆汁甚至会损伤肠道的黏膜。目前认为胆汁是较明确的致癌因素,与消化道肿瘤的相关性较大,但仍缺乏针对性的防治方案。明确胆汁对消化道黏膜的损伤机制,有助探索消化道肿瘤防治的新靶点。本文回顾了近年来有关胆汁对食管黏膜、胃黏膜及肠黏膜损伤机制的研究进展,以期为进一步的研究提供思路。     

Independent sources of condition dependency and multiple pathways determine a composite trait: lessons from carotenoid‐based plumage colouration

Many colour ornaments are composite traits consisting of at least four components, which themselves may be more complex, determined by independent evolutionary pathways, and potentially being under different environmental control. To date, little evidence exists that several different components of colour elaboration are condition dependent and no direct evidence exists that different ornamental components are affected by different sources of variation. For example, in carotenoid‐based plumage colouration, one of the best‐known condition‐dependent ornaments, colour elaboration stems from both condition‐dependent pigment concentration and structural components. Some environmental flexibility of these components has been suggested, but specifically which and how they are affected remains unknown. Here, we tested whether multiple colour components may be condition dependent, by using a comprehensive 3 × 2 experimental design, in which we carotenoid supplemented and immune challenged great tit nestlings (Parus major) and quantified effects on different components of colouration. Plumage colouration was affected by an interaction between carotenoid availability and immune challenge. Path analyses showed that carotenoid supplementation increased plumage saturation via feather carotenoid concentration and via mechanisms unrelated to carotenoid deposition, while immune challenge affected feather length, but not carotenoid concentration. Thus, independent condition‐dependent pathways, affected by different sources of variation, determine colour elaboration. This provides opportunities for the evolution of multiple signals within components of ornamental traits. This finding indicates that the selective forces shaping the evolution of different components of a composite trait and the trait's signal content may be more complex than believed so far, and that holistic approaches are required for drawing comprehensive evolutionary conclusions.