Transgenic and recombinant resistin impair skeletal muscle glucose metabolism in the spontaneously hypertensive rat

Increased serum levels of resistin, a molecule secreted by fat cells, have been proposed as a possible mechanistic link between obesity and insulin resistance. To further investigate the effects of resistin on glucose metabolism, we derived a novel transgenic strain of spontaneously hypertensive rats expressing the mouse resistin gene under the control of the fat-specific aP2 promoter and also performed in vitro studies of the effects of recombinant resistin on glucose metabolism in isolated skeletal muscle. Expression of the resistin transgene was detected by Northern blot analysis in adipose tissue and by real-time PCR in skeletal muscle and was associated with increased serum fatty acids and muscle triglycerides, impaired skeletal muscle glucose metabolism, and glucose intolerance in the absence of any changes in serum resistin concentrations. In skeletal muscle isolated from non-transgenic spontaneously hypertensive rats, in vitro incubation with recombinant resistin significantly inhibited insulin-stimulated glycogenesis and reduced glucose oxidation. These findings raise the possibility that autocrine effects of resistin in adipocytes, leading to release of other prodiabetic effector molecules from fat and/or paracrine actions of resistin secreted by adipocytes embedded within skeletal muscle, may contribute to the pathogenesis of disordered skeletal muscle glucose metabolism and impaired glucose tolerance.     

中国楼梯草属(荨麻科)几种植物的订正

根据对中国楼梯草属Elatostema植物标本的研究,将碧江楼梯草E．bijiangense归并入楼梯草E． involucratum,长叶墨脱楼梯草E．medogense var．oblongum和树志楼梯草E．shuzhii归并入墨脱楼梯草E． medogense,光茎钝叶楼梯草E．obtusum var．glabrescens归并入三齿钝叶楼梯草E．obtusum var．trilobula- tum,三裂楼梯草E．sinense var．trilobatum归并入对叶楼梯草E．sinense,赤水楼梯草E．strigulosum var．semitripilinerve归并入伏毛楼梯草E．strigulosum。     

中国伞形科变豆菜亚科的果实解剖特征及其系统学意义

对中国伞形科变豆菜亚科 (Saniculoideae) 2属 (变豆菜属SaniculaL .和刺芹属EryngiumL .) 13种植物的果实形态结构进行了比较解剖学观察 ,从果实横切面形状及其合生面宽度、外果皮和中果皮外突所呈皮刺和鳞片或瘤状体的形态及皮刺中木化厚壁细胞组织的分布、外果皮细胞形状及其角质层厚度、中果皮细胞层数和结晶体类型及分布、色素块沉积、伴生分泌管和油管的大小及分布等方面对上述各属种进行了观察和分析 ,归纳出各属的果实解剖特征 ,探讨了属间演化水平 ,认为刺芹属果实较变豆菜属果实演化程度高。结合已有的研究结果 ,讨论了该亚科与伞形科天胡荽亚科 (Hydrocotyloideae)间的区别及其演化关系。     

荞麦亲和与不亲和授粉后柱头和花粉管中ATP酶的超微细胞化学定位

利用磷酸铅淀淀技术对荞麦（Fagopyrum esculentum Monch.)pin型植株分别进行亲和授粉和不亲和授粉后的柱头、花粉粒、花粉管进行了ATPase的超微细胞化学定位。结果表明（1）亲和授粉和不亲和授粉后0.5h,柱头细胞的ATPase活性反应水平较低或基于无酶活性;柱头表面、柱头上附着的花粉粒内ATPase活性在不亲和授粉时较低,亲和授粉时较高,花粉粒内ATPase主要定位于线粒体和精子细胞;（2）授粉后1.5h,不亲和授粉的柱头细胞及花粉管的ATPase活性均较低,花粉管停止生长,细胞质开始解体;而亲和授粉的柱头细胞及花粉管的ATPase活性均较高,ATPase主要定位于柱头细胞的质膜、胞基质以及花粉管的壁、质体的膜、高尔基体、线粒体上。根据不同时期不同部位ATPase活性的差异,我们认为荞麦发生自交不亲和时,花粉管在花柱中停止生长不仅是因此花粉管得不到花柱中的营养物质而引起的,可能也与花粉管自身物质代谢发生障碍有关。     

大黄醇提物对嗜水气单胞菌抑菌活性及其机制

研究大黄醇提物对嗜水气单胞菌的抑菌活性及机制。主要采用牛津杯法和液体倍比稀释法;通过扫描电镜、SDS-PAGE、二维电泳及串联质谱等方法探讨大黄醇提物对嗜水气单胞菌的抑菌机制。结果显示,大黄醇提取物对嗜水气单胞菌有明显的抑制效果,抑菌圈为(24.5±0.2)mm,MIC和MBC均为3.91 mg/m L;在药物作用下,菌体表面变粗糙,细胞膜受损并出现破裂;在经药物处理4 h后,细菌蛋白含量明显下降(P0.05),2-DE电泳发现3个差异性蛋白。结果表明,大黄醇提物对嗜水气单胞菌的抑制作用机制是破坏其细胞膜结构及影响特定蛋白的表达。     

Linking seed germination and plant height: a case study of a wetland community on the eastern Tibet Plateau

• Seed germination is the earliest trait expressed in a plant's life history, and it can directly affect the expression of post‐germination traits. Plant height is central to plant ecological strategies, because it is a major determinant of the ability of a species to compete for light. Thus, linking seed germination and plant height at the community level is very important to understanding plant fitness and community structure.
• Here, we tested storage condition and temperature requirements for germination of 31 species from a wetland plant community on the eastern Tibet Plateau and analysed correlation of germination traits with plant height in relation to storage condition.
• Germination percentage was positively related to plant height, and this relationship disappeared when seeds were incubated at a low temperature (i.e. 5 °C) or after they were stored under wet‐cold conditions. The response of seeds to dry+wet–cold storage was negatively related to plant height. Based on the scores of each species on the first two principal components derived from PCA, species were classified into two categories by hierarchical clustering, and there was a significant difference between germination and plant height of species in these two categories.
• These results suggest that the requirements for seed germination together with seasonal change in environmental conditions determine the window for germination and, in turn, plant growth season and resource utilisation and ultimately plant height.

     

基于地统计学的黄土高寒区典型林地土壤水分盈亏状况研究

土壤水分是黄土高寒区水循环、地下水补给和植被恢复的关键因素,基于地统计学研究土壤水分空间分布及其盈亏状况,揭示林地土壤水分的空间分布规律、变异特征及空间结构,对于区域植被恢复具有重要价值。以大通县安门滩小流域人工林地作为研究对象,运用地统计学方法对其5月、7月和9月的土壤储水量、林地耗水量和土壤水分盈亏量进行综合分析。研究结果表明:(1)土壤储水量总体表现为9月5月7月,而林地耗水量为7月9月5月,5—7月绝大多数林地的土壤水分呈亏损状态,而7—9月所有林地土壤水分都得到了补充,总体来看,5—9月研究区多数林地的土壤水分有所盈余,土壤储水量、林地耗水量和土壤水分盈亏量均采用指数模型作为最优理论变异函数模型;(2)5月、7月和9月土壤储水量呈南高北低、西高东低的空间分异规律,且西南-东北方向变异较东南-西北方向剧烈;各月林地耗水量在西南-东北方向变异较东南-西北方向剧烈,总体表现为西南部区域低于东北部区域;在5—7月、7—9月和5—9月这三个时期内,土壤水分盈亏量的取值均呈现出东北部区域小于西南部区域的特点。综上,当地土壤水分状况与林地耗水量分布格局并不完全匹配,虽然绝大部分林分能够维持土壤水分收支平衡,但部分山脚处的青杨林地和中部区域的华北落叶松林地出现了土壤水分亏损的现象。为防止林地水分环境恶化,在之后黄土高寒区的植被建设过程中,应适当调整林分配置。     

副溶血性弧菌-霍乱弧菌混合生物被膜形成过程研究

【目的】研究副溶血性弧菌(Vibrioparahaemolyticus,VP)和霍乱弧菌(Vibriocholera,VC)混合生物被膜的形成过程。【方法】在4、8、12、24、36、48、60、72 h测定单独条件下VP、VC及其混合后生物被膜的形成情况,通过结晶紫染色法、平板菌落计数法、测定胞外多糖、胞外蛋白,通过荧光原位杂交(FISH)观察混合生物被膜形成。【结果】虽然形成的混合生物被膜量介于VC和VP之间,但混合生物被膜在形成过程中,成熟期后生物被膜量的变化较小,对环境的抗性增强。混合生物被膜中拥有更多的活菌,混合生物被膜形成过程中胞外蛋白和胞外多糖的变化体现出其可能在对抵御不适应环境中起重要作用,通过FISH可观察到不同时期生物被膜的变化过程。【结论】VC与VP共同形成生物被膜的过程中,混合生物被膜总量虽然减少,但混合生物被膜中拥有更多的活菌,这可能引起更大的危害。研究混合生物被膜形成过程中被膜的变化,可为有害生物被膜的控制提供基础。     

低温碱性蛋白酶菌株的筛选及产酶条件的研究

从 2 0株枯草芽孢杆菌筛选出了 1株产低温碱性蛋白酶菌株 ;并通过单因子实验、正交实验确定该菌株的最佳培养基为 :葡萄糖 8%,豆粕粉 6 %,Tween80 0 .0 3%,KH2 PO4 0 .0 6 %;确定了酶作用的最适条件为 30℃。