Rapid detection of Shigella species in environmental sewage by an immunocapture PCR with universal primers

In the present study, we developed a quick, highly specific method for detection of Shigella species by combining immunocapturing of the bacteria and a universal primer PCR. The method drastically enhances test sensitivity, and it can be used not only for identification of Shigella species in the environment but also for rapid detection of other pathogens.     

Cathepsin B-mediated Autophagy Flux Facilitates the Anthrax Toxin Receptor 2-mediated Delivery of Anthrax Lethal Factor into the Cytoplasm

Anthrax lethal toxin (LeTx) is a virulence factor secreted by Bacillus anthracis and has direct cytotoxic effects on most cells once released into the cytoplasm. The cytoplasmic delivery of the proteolytically active component of LeTx, lethal factor (LF), is carried out by the transporter component, protective antigen, which interacts with either of two known surface receptors known as anthrax toxin receptor (ANTXR) 1 and 2. We found that the cytoplasmic delivery of LF by ANTXR2 was mediated by cathepsin B (CTSB) and required lysosomal fusion with LeTx-containing endosomes. Also, binding of protective antigen to ANXTR1 or -2 triggered autophagy, which facilitated the cytoplasmic delivery of ANTXR2-associated LF. We found that whereas cells treated with the membrane-permeable CTSB inhibitor CA074-Me- or CTSB-deficient cells had no defect in fusion of LC3-containing autophagic vacuoles with lysosomes, autophagic flux was significantly delayed. These results suggested that the ANTXR2-mediated cytoplasmic delivery of LF was enhanced by CTSB-dependent autophagic flux.     

Bayesian analysis of genetic architecture of quantitative trait using data of crosses of multiple inbred lines

Using the data of crosses of multiple of inbred lines for mapping QTL can increase QTL detecting power compared with only cross of two inbred lines. Although many fixed-effect model methods have been proposed to analyze such data, they are largely based on one-QTL model or main effect model, and the interaction effects between QTL are always neglected. However, effectively separating the interaction effects from the residual error can increase the statistical power. In this article, we both extended the novel Bayesian model selection method and Bayesian shrinkage estimation approaches to multiple inbred line crosses. With two extensions, interacting QTL are effectively detected with high solution; in addition, the posterior variances for both main effects and interaction effects are also subjected to full Bayesian estimate, which is more optimal than two step approach involved in maximum-likelihood. A series of simulation experiments have been conducted to demonstrate the performance of the methods. The computer program written in FORTRAN language is freely available on request.     

苋菜甜菜红素合成相关基因AmMYB1的克隆及表达分析

应用RACE技术,从‘大红’苋菜中克隆到1条MYB基因cDNA全长序列,命名为AmMYB1(登录号为KU557504)。AmMYB1基因开放阅读框为723bp,可编码240个氨基酸。其基因组序列与cDNA比对后显示,AmMYB1基因含有1个内含子。生物信息学分析表明,AmMYB1具有2个连续的MYB结构域,是一个典型的R2R3-MYB;同源分析显示,该基因编码的氨基酸序列与甜菜红素相关BvMYB1的一致性最高,达到54%。亚细胞定位结果显示,AmMYB1蛋白定位于细胞核。实时荧光定量PCR分析表明,AmMYB1基因在‘大红’苋菜叶片红色部位的表达量高于绿色部位;在甜菜红素含量高的叶和茎中表达量明显高于根;在光照条件下表达量高于遮光处理;在红叶品种中的表达量高于绿叶品种。研究结果表明,AmMYB1基因可能是苋菜甜菜红素合成途径中重要的正调控因子。     

Further geometric morphometric analysis on the genus Eysarcoris (Hemiptera: Pentatomidae) from China

Further geometric morphometric analysis of the genus Eysarcoris was done based on the former studies to classified the nine Eysarcoris species from China.In this study,six characters,such as forewing,hindwing,pygophore,head,pronotum and scutellum,were selected to investigate the shape variation of Eysarcoris.Significant divergence in the shapes of the six characters was observed among the species (p ＜ 0.05).For all methods,phenetic similarity based on the six characters agrees with the current status of the genus.The cluster analysis of eight species are consistent with the traditional morphological studies.CVA analysis also shows that the values of the six characters are not equal in taxonomy.Pygophore,forewing,hindwing and pronotum play more important roles in the classification.     

低剂量杀虫剂对星豹蛛捕食效应的影响及其机理

探讨低剂量杀虫剂对蜘蛛捕食效应的影响及其生化机理。采用药膜法,测定了低剂量吡虫啉作用下,星豹蛛和甘蓝蚜敏感性、捕食效应以及成蛛体内乙酰胆碱酯酶(AChE)、谷胱甘肽S-转移酶(GSTs)、超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和中肠蛋白消化酶的活力变化。低剂量农药作用下,星豹蛛对甘蓝蚜的功能反应类型为HollingⅡ型,与对照组相比,随着猎物密度的增大星豹蛛的捕食量增加,寻找效应降低,对猎物的处理时间Th缩短,从而增强了对猎物的捕食作用;低剂量农药处理后,星豹蛛体内AChE和GSTs活性均显著低于对照组(P0.05),说明酶活性受到抑制,且抑制作用随吡虫啉浓度的增大而加强,随作用时间的延长而减弱;SOD,CAT和中肠蛋白消化酶活性显著增强,与对照组相比存在显著或极显著差异(P0.05),且随吡虫啉浓度增大和作用时间的延长而逐渐降低,最后接近对照组。低剂量杀虫剂作用下,蜘蛛体内AChE活性受到抑制,AChE敏感性降低,对神经递质乙酰胆碱的分解作用下降,使蜘蛛的兴奋性增加;GSTs、SOD、CAT等代谢酶活性发生变化,使蜘蛛的新陈代谢加速,从而刺激捕食;中肠蛋白消化酶的活性增强,提高了对猎物的消化吸收功能。总之,在低剂量杀虫剂作用下,星豹蛛通过外在的捕食行为和体内一系列酶系生理生化反应的综合作用促进蜘蛛对害虫的控制作用。     

拟南芥不定芽发生早期的数字基因表达谱分析

目前,有关不定芽发生的研究主要集中在单基因的调控方面,缺乏转录组方面的系统研究.利用RNA-seq高通量测序技术在全基因组范围内检测了不定芽发生早期的基因表达谱,共检测到2457个差异表达基因.这些基因参与了激素代谢和信号转导、愈伤组织和侧根的形成、茎顶端分生组织的发育和光合作用等过程.进一步的途径富集分析表明,不定芽发生早期苯丙氨酸代谢和苯丙胺素合成等途径相关的基因显著富集.并且苯丙氨酸可以显著抑制不定芽的发生,暗示了苯丙氨酸代谢和苯丙胺素的合成可能在不定芽发生过程起着重要的作用.     

猪源大肠杆菌耐药质粒图谱及耐药性分析

目的:探讨猪大肠杆菌的耐药质粒图谱、耐药性及耐药基因之间的关系。方法:从湖南省株洲、益阳的四个猪场分离出9株大肠杆菌,进行质粒电泳图谱分析、用PCR法检测耐喹诺酮类耐药基因Gyr A、Par C和耐四环素类耐药基因Tet A、Tet B,并采用Kirby-bauer法对这9株大肠杆菌进行药敏(18种抗生素)试验。结果:其中9株大肠杆菌含有三条或者三条以上的质粒条带,且其质粒谱型均不相同;9株大肠杆菌均检测出4种耐药基因Gyr A、Par C、Tet A和Tet B;9株大肠杆菌对所选用的抗生素存在不同程度的耐药性,其中7株大肠杆菌对10种或10种以上的抗生素耐药,最高对13种抗生素耐药,氨苄西林、青霉素、阿莫西林、红霉素的耐药率达100%,对四环素、多西环素的耐药率达到88.9%,而多粘菌素B、阿奇霉素、大观霉素耐药率较低。结论:耐药性与质粒条带数、耐药基因之间并无明显的相关性;猪大肠杆菌呈多重耐药之势,在治疗大肠杆菌病时最好根据药敏实验结果选用合适的抗生素。     

Dihydroartemisinin increases gemcitabine therapeutic efficacy in ovarian cancer by inducing reactive oxygen species

Ovarian cancer is the major cause of death in women gynecological malignancy and gemcitabine (GEM) is commonly used in related chemotherapy. However, more than 90% GEM is catalyzed into an inactive metabolite 2′-deoxy-2′,2′-difluorouridine by stromal and cellular cytidine deaminase (CDA). Dihydroartemisinin (DHA), which possesses an intramolecular endoperoxide bridge, could be activated by heme or ferrous iron to produce reactive oxygen species (ROS). The excess ROS generation will excite expression of heme oxygenase-1 and suppress CDA expression. Under low CDA expression, the inactivation of GEM is decreased in turn to exert excellent therapeutic efficiency. Herein, we first studied the ROS generation by DHA in vitro with A2780 cells by means of flow cytometry and confocal laser scanning microscopy. Furthermore, cytotoxicity assay in vitro showed that DHA + GEM had synergistic effect, with molar ratio of DHA and GEM at 10. Eventually, in A2780 ovarian cancer xenograft tumor model, DHA + GEM exhibited significant antitumor efficiency with lower blood toxicity than GEM alone. Noteworthy, the combination treatment group completely eliminated the tumors on day 14.     

太湖梅梁湾沿岸带水体生物学与光学特性

基于 1998～ 1999年周年 4季原位水下光场观测资料及中国科学院太湖湖泊生态系统研究站 1992～ 2 0 0 1年悬浮物、叶绿素 a、透明度长期历史观测资料分析了太湖梅梁湾沿岸带第 2号站点水体的生物学与光学特性 ,探讨了水下光合有效辐射(PAR)总量的日变化、垂直分布 ;光衰减系数的季节变化及光谱分布 ;影响光衰减系数的主要水色因子。结果表明 ,无论是 PAR还是光谱衰减系数其值都很高 ,其中 PAR衰减系数在 1.4 0～ 5 .30 / m间变化 ,均值为 2 .4 3± 0 .5 5 / m,秋季最大、夏季最小 ,真光层深度在 0 .87～ 3.2 9m间变化 ,均值为 1.98± 0 .4 1m;水下光谱在蓝光波段衰减最强烈 ,其次是红光、绿光 ,随着深度增加光谱成分出现绿移和红移现象 ,绿红光占得比例越来越大 ;光谱衰减系数随着波长的增加大致呈下降趋势 ,但在 6 70 nm附近有个峰值 ;基于线性相关分析发现在混浊的沿岸带水体中影响光衰减主要因子为水体中的悬浮物和有色可溶性有机物 ,叶绿素 a对 PAR衰减系数的贡献率只占到 1.5 9%～ 14 .2 1%。