通过RAPD分析揭示五种淡水无齿蚌（软体动物门：双壳类）的遗传多样性

Unionidae(Bivalvia)are distributed infreshwaters,and represent a significanttaxonof benthic community[1].In China,freshwater mussels are abundant resources[2].Since1949,substantial investigations onthe unionidfau-na had been undertakenin China[3—8].Withreference tooverseas research[9,10],a preliminary reorganization onthe Unionidae was performed accordingtosome classifica-tion characteristics such as shell shape,larvae character-istics,and breeding habit[11].Due tothe serious conver-gence o…     

Overexpression of the OsPDCD5 Gene Induces Programmed Cell Death in Rice

The primary aim of the present study was to investigate the overexpression of the rice （Oryza sativa L.） programmed cell death 5 （OsPDCD5） gene in rice plant. Constitutive expression of OsPDCD5 from the cauliflower mosaic virus （CaMV） 35S promoter induced programmed cell death （PCD） in transgenic rice. Programmed cell death was accompanied by typical features, including inhibition of developmental growth, a reduction of fresh weight, degradation of total protein content, and fragmentation of genomic DNA. These results suggest that OsPDCD5 plays an essential role in the regulation of PCD in rice plants.     

大型真菌重金属污染生态学研究进展与展望

大型真菌是生物圈中重要的组成部分和生态资源,在自然界物质循环和维持生态平衡中发挥着非常重要的作用.本文从环境重金属污染对大型真菌的生态毒性效应、大型真菌对重金属的生物富集作用、大型真菌对重金属污染的生态适应机制、大型真菌对重金属污染的指示和生态修复作用等方面,较为全面地总结、评述了大型真菌重金属污染生态学的研究进展.随着重金属污染的加剧,加强研究大型真菌重金属污染生态学,对于大型真菌资源的合理利用和污染环境的生态修复具有重要的现实意义.     

Predator-induced changes of male and female mating preferences: innate and learned components

While many mati ng pref ere nces have a genetic basis, the question remai ns as to whether and how learning/experience can modify individual mate choice decisions. We used wild-caught (predator-experienced) and Fi laboratory-reared (predator-naive) invasive Western mosquitofish Gambusia affinis from China to test whether mating preferences (assessed in a first mate choice test) would change under immediate predation threat. The same individuals were tested in a second mate choice test during which 1 of 3 types of animated predators was presented: 1) a co-occurring predator, 2) a co-evolved but not currently co-occurring predator, and 3) a non-piscivorous species as control. We compared preference scores derived from both mate choice tests to separate innate from experiential effects of predation. We also asked whether predator-induced changes in mating preferences would differ betwee n sexes or depend on the choosing individual's personality type and/or body size. Wild-caught fish altered their mate choice decisions most when exposed to the co-occurring predator whereas laboratory-reared individuals responded most to the co-evolved predator, suggesting that both innate mechanisms and learning effects are involved. This behavior likely reduces individuals' risk of falling victim to predation by temporarily moving away from high-quality (i.e., conspicuous) mating partners. Accordingly, effects were stronger in bolder than shyer, large- compared with small-bodied, and female compared with male focal individuals, likely because those phenotypes face an increased predation risk overall. Our study adds to the growing body of literature appreciating the complexity of the mate choice process, where an array of intrinsic and extrinsic factors interacts during decision-making.     

用电脉冲法将外源质粒DNA导入花生根瘤菌的研究

利用基因电转移仪(Gene Pulser^TM|),对快、慢生型花生根瘤菌85-7和1 47-3的电转化条件进行了系统的研究。结果表明:在对数中期(ABC~600|为0.6-0.7)收获的细胞在最高场强(12.5kV/cm)和短脉冲时间(2.5-5.0m sec)时达到最高转化效率(10 E5转化子/μgDNA)。转化子数随DNA终浓度在一定范围(26.24pg-1.5μg/ml)内呈线性增加, 随即表现出“饱和效应”。增加受体菌细胞浓度,能提高电转化效率;而质粒分子量的增加(11.9 -166kb)却使电转化效率降低。来自受体菌自身的同源质粒,因克服了宿主的限制-修饰性,可以极显著地提高电转化效率。电脉冲处理对受体菌自发突变没有影响。 Abstract:A systematic study of transformation conditions of peanut rhizobia 85-7 and 147-3 was conducted by using Bio-Rad Gene Pulser equipment.It was revealed that the highest transformation efficiency(105 transformants/μgDNA) was obtained from cells harvested at mid-log phase of ABC600 on 0.6-0.7 under the highest field strength(12.5kV/cm)and a short pulse length(2.5-5.0 msec).A linear increase of transformants was observed when DNA concentration was increased in the range of 26.24pg-1.5μg/ml and it became saturation afterwards.Transformation efficiency was also increased with the raise of recipient cell concentrations,but decreased with the increase of plasmid sizes from 11.9 to 166kb.A significant increase of transformation efficiency was revealed with the homologous plasmid isolated from fecipient itself since the effects of host restriction and modification were avoided.No significant effect of electroporation on spontaneous mutation was observed.     

线纹香茶菜酸的化学结构

从线纹香茶菜Ｒａｂｄｏｓｉａ ｖａｒ．ｌｏｐｈａｎｔｈｏｉｄｅｓ Ｈａｒａ中分得五种成分,其中之一线纹香茶菜酚为Ａｂｉｅｔａｎｅ ａｃｉｄ型的新二萜酸。根据波谱解析、衍生物制备及Ｘ线单晶衍射,测定了它的化学结构。其余四种成分,分别鉴定为２ａ－羟基乌索酸、齐墩果酸、β－谷甾醇及β－谷甾醇－Ｄ－葡萄糖甙。     

Agrobacterium-mediated transformation and assessment of factors influ-encing transgene expression in loblolly pine (Pinus taeda L.)

INTRODUCTIONRecombinant DNA technology is a powerful toolfor the introduction of foreign genes into longlivedperennials and fOr fundamelltal studies of gene expression. Using such techniques, we can overcomethe difficulties associated with the breeding of a long-lived perennial. At present, although considerablereseaxch effort has been devoted to the genetic en-gineering of fOrest trees, it has lagged behind ad-vances made in herbaceous crops due both to eco-nomics and the recalcitrant n…     

种新的蛋白酪氨酸磷酸酶基因的克隆、定位和组织表达谱研究

从人胎肝cDNA文库分离出一长度为5248bp的cDNA克隆,该基因包含26个外显子和25个内含子,染色体定位于在某些肿瘤细胞中易缺失的3p21.1-21.33.其可读框编码1636个氨基酸,该蛋白属于蛋白酪氨酸磷酸酶(PTP)家族,其C端有一个典型的PTP结构域,N端含有约800氨基酸残基的BRO1样结构域及随后2个可能的SH3结构域结合位点,在这两个结构域之间及C末端还各有一个脯氨酸富集区.Northern杂交和点杂交分析显示,该基因以大约5.4kb的单一转录物广泛表达于人体各种组织,而且在人部分肿瘤细胞中高表达.结果提示,人源PTP-TD14是一个新的蛋白酪氨酸磷酸酶。 Abstract:A human cDNA of 5248bp encoding a novel protein tyrosine phosphatase PTP-TD14(1636aa) has been isolated from fetal liver.The gene is located at chromosome 3p21.3,an area frequently deleted in many types of cancer,and composed of at least 26 exons and 25 introns.The phosphatase has unique features in its domain structure:a tyrosine phosphatase domain,a C-terminal PEST motif,two SH3-binding motifs,two proline-rich region and an N-terminal domain similar to yeast BRO1 (a yeast protein that is involved in the mitogen-activated protein kinase signaling pathway).Northern blot and dot blot hybridizations indicate that it is expressed ubiquitously in human 50 tissues and 7 cancer cell lines.Thus,it is a novel protein tyrosine phosphatase gene located on 3p21.3.     

西藏色季拉山林线冷杉种群结构与动态

急尖长苞冷杉(Abies georgei var.smithii)是西藏东南部地区高山林线森林群落的主要建群树种,主要分布在色季拉山海拔3600～4400m区域,并成为阴坡高山林线的优势树种。通过对色季拉山林线群落交错区域的定位调查,分析了急尖长苞冷杉的个体生长、种群结构与动态以及林线特征。分析结果表明:(1)西藏色季拉山海拔4320m处为森林郁闭上限,该区域存在两种类型的高山林线,阳坡为渐变型林线,林线树种为方枝柏(Sabina saltuaria);阴坡为急变型林线,林线树种为急尖长苞冷杉。阳坡与阴坡林线分布海拔上限分别为4570m和4390m,阳坡高于阴坡180m;阳坡与阴坡林线群落交错区垂直宽度分别为250m和70m,阳坡比阴坡宽180m。(2)阴坡海拔3700～3800m属急尖长苞冷杉分布的最适范围,种群径级结构表现为典型的反"J"型,种群密度约380株/hm2;种群年龄结构表现为"金字塔"型,属于扩展型种群。(3)静态生命表和种群存活曲线反映了急尖长苞冷杉种群在形成初期的20a和生长发育的60～160a分别经历了强烈的环境筛选和竞争自疏,以及后期与环境变化相关的死亡波动,200a左右为急尖长苞冷杉的生理寿命,种群后期基本稳定,400a左右为极限寿命。