麦长管蚜的抗药性研究

麦蚜在我国分布广、为害重,又传播病毒病,是小麦的重要害虫。近年麦蚜的发生为害有增长的趋势,有些地方反映农药防效下降、用药次数增加。本文介绍1983—1987年5年中采用6个省市的8个地区麦蚜种群对6种农药进行了点滴法毒力测定。探明了张掖和高台麦长管蚜[sitobion avenae (Fab.)]对氧化乐果产生10—15倍抗药性。用英国Rothamsted试验站的比色板试验法进行生化测定,结果同生物测定一致。作者认为该法是一种探测蚜虫抗药性简便可行的定性方法。用北京室内饲养的麦长管蚜以16种新老农药品种用点滴法进行了敏感水平测定,建立了麦长管蚜对16种供试农药的毒力基线。这对探测麦蚜抗药性、监测其抗药性动态变化打下一定基础。通过室内毒力测定、田间药效试验和20多万亩的大面积示范推广,作者提出杀螟松是防治麦蚜较理想的候选农药品种,以替换当前使用的药效已下降的乐果和氧化乐果、替换当前使用的毒性很高的杀虫剂甲胺磷。     

人类β—arrestin1 cDNA的克隆,表达及功能的研究

用生物信息法获得了人类β－ａｒｒｅｓｔｉｎ１两个亚型（１Ａ和１Ｂ）的全长编码离列ｃＤＮＡ。β－ａｒｒｅｓｔｉｎ１Ａ可以在大肠杆菌中高效表达，部分产物以包涵体形式存在，利用纯化的包涵体在小鼠中制备了抗血清。免疫印迹法分析表明，对其功能的研究证明，β－ａｒｒｅｓｔｉｎ１Ａ可以强烈削弱共表达的阿片受体对抑制性Ｇ蛋白的激活。     

Mutations of Gln64 in the HIV-1 gp41 N-terminal heptad repeat render viruses resistant to peptide HIV fusion inhibitors targeting the gp41 pocket

To prove that the peptidic HIV-1 fusion inhibitors containing the pocket-binding domain (PBD) mainly target the hydrophobic pocket in the gp41 N-terminal heptad repeat (NHR), we constructed pseudoviruses by replacement of Q64 in the gp41 pocket region with Ala (Q64A) or Leu (Q64L). These viruses were highly resistant to C34 and CP32M containing the PBD, while they were susceptible to T20 (enfuvirtide) lacking the PBD but containing the GIV-motif-binding domain (GBD) and lipid-binding domain (LBD). They were also sensitive to C52L, which contains the PBD, GBD, and LBD. Those mutations may disrupt the hydrophilic interaction between Q64 in the NHR and N113 in the peptides containing the PBD. This report provides insights into the mechanisms of drug resistance, with implications for the design of novel HIV fusion and entry inhibitors.     

铅胁迫对斜纹夜蛾生长发育与生殖的影响

在植食性昆虫斜纹夜蛾幼虫标准人工饲料中添加不同浓度的重金属铅(Pb),研究Pb胁迫对其生长发育与生殖的影响.结果表明:斜纹夜蛾不同发育阶段(幼虫、蛹和成虫)的存活率和体质量随着饲料中Pb浓度的增加而下降,引起存活率显著下降的最低Pb胁迫浓度是100 mg·kg-1,引起体质量显著减少的最低Pb胁迫浓度是50 mg·kg-1.在取食Pb浓度为25～ 200 mg·kg-1的人工饲料后,斜纹夜蛾成虫的产卵天数显著减少;产卵力和生育力随着饲料中Pb浓度的增加而显著下降;1000粒卵的平均质量显著低于对照;卵孵化率显著下降.重金属Pb胁迫对斜纹夜蛾生长发育和生殖具有显著的抑制作用.     

鞍叶羊蹄甲茎皮的化学成分研究

采用柱色谱方法,从鞍叶羊蹄甲(Bauhinia brachycarpa)茎皮95%乙醇提取物的氯仿和乙酸乙酯萃取部位分离得到10个化合物。经理化性质和波谱分析确定其结构分别为:羽扇豆醇(1)、β-谷甾醇(2)、5,6,7,5’-tetramethoxy-3’,4’-methylene-dioxyflavone(3)、5,6,7,3’,4’,5’-hexanmethoxyflavone(4)、5,7,3’,4’,5’-pentame-thoxyflavone(5)、5,6,7,-trimethoxy-3’,4’-methylene-dioxyflav one(6)、胡萝卜苷(7)、没食子酸(8)、没食子酸甲酯(9)和没食子酰表儿茶素(10),所有化合物均为首次从该种植物分离得到。     

微RNA在卵巢上皮性癌发生发展中作用及其临床意义

研究表明,miRNA参与了胚胎发育、损伤修复、糖尿病、心脏病等许多重要生理病理过程,特别是在恶性肿瘤的发生发展中发挥了重要作用,并具有潜在的临床意义。本文比较详细地叙述了有关miRNA的重要基础研究成果,并就miRNA在卵巢癌组织及细胞中的表达、miRNA在卵巢癌发生发展中的作用、miRNA与卵巢癌早期诊断、化疗耐药及预后判断等方面的最新研究成果进行了综述。     

厌氧条件下希瓦氏菌腐殖质还原对偶氮还原的影响

以希瓦氏菌属的3个代表种为研究对象,研究了在厌氧条件下腐殖质的存在对偶氮还原的影响。实验结果表明:3个代表菌株在厌氧条件下都有高效的偶氮还原和腐殖质还原功能,1mmol/L偶氮染料在24h内完全脱色,并且偶氮还原与电子供体氧化存在着紧密的偶联关系。腐殖质物质模式物2-磺酸蒽醌AQS在小于1~2mmol/L条件下能显著加速偶氮还原,12h就完全脱色,3mmol/L时18h完全脱色。但当浓度大于3mmol/L时则对偶氮还原产生明显抑制作用。另一腐殖质模式物2,6-双磺酸蒽醌AQDS其浓度在1~3mmol/L以内亦使脱色在12h内完成,4~6mmol/L时15h左右完成脱色。7~12mmol/L仍有一定的脱色促进作用,但随着浓度的提高,其促进作用也逐渐减弱。这说明腐殖质的确可以作为氧化还原中间体穿梭于电子供体与染料的偶氮双键之间促进偶氮还原。但当其浓度达到某一阈值时它就显出与偶氮键竞争电子的本质,从而使偶氮还原速率下降。原因在于他们的氧化还原电势的差异,导致细菌呼吸链的电子递体对腐殖质物质和偶氮键的亲和力不同,从而使不同腐殖质浓度对偶氮键还原产生了不同的影响。     

不同罗汉果杂交品系花粉数量和发芽率的比较研究

检测和比较了源于3种杂交方式的26个罗汉果雄株品系及4个亲本对照品种的花粉量和花粉发芽率,结果表明:11个近交品系间的花粉量和花粉发芽率均存在着显著差异,花粉量最高的是长滩果T-24品系(3.76×10~4),花粉发芽率最高的是青皮果Q-11品系(90.3%);12个单交品系及4个亲本对照品种之间在花粉量上有所不同,而在花粉发芽率上差异较大,大部分达显著或极显著水平;3个双交品系与2个亲本对照品种在花粉量上有极显著的差异,K2-85品系的花粉量明显高于两个亲本对照品种;3种杂交方式所得品系的平均值比较,花粉量高低顺序为双交(3.45×10~4)>单交(3.12×10~4)>近交(2.75×10~4),花粉发芽率高低顺序为单交(58.2%)>近交(46.9%)>双交(34.5%)。因此不仅选择出较好的杂交雄株于生产上应用是可行的,而且还有可能获得天然败育雄株用于培育无籽罗汉果。     

Transmembrane helix of novel oncogene with kinase-domain (NOK) influences its oligomerization and limits the activation of RAS/MAPK signaling

Ligand-dependent or independent oligomerization of receptor protein tyrosine kinase (RPTK) is often an essential step for receptor activation and intracellular signaling. The novel oncogene with kinase-domain (NOK) is a unique RPTK that almost completely lacks an ectodomain, expresses intracellularly and activates constitutively. However, it is unknown whether NOK can form oligomer or what function oligomerization would have. In this study, two NOK deletion mutants were generated by either removing the ectodomain (NOKΔECD) or including the endodomain (NOK-ICD). Co-immunoprecipitation demonstrated that the transmembrane (TM) domain of NOK was essential for its intermolecular interaction. The results further showed that NOK aggregated more closely as lower order oligomers (the dimer- and trimer-sized) than either deletion mutant did since NOK could be cross-linked by both Sulfo-EGS and formaldehyde, whereas either deletion mutant was only sensitive to Sulfo-EGS. Removing the NOK TM domain (NOK-ICD) not only markedly promoted higher order oligomerization, but also altered the subcellular localization of NOK and dramatically elevated the NOK-mediated constitutive activation of extracellular signal-regulated kinase (ERK). Moreover, NOK-ICD but not NOK or NOKΔECD was co-localized with the upstream signaling molecule RAS on cell membrane. Thus, TM-mediated intermolecular contacting may be mainly responsible for the constitutive activation of NOK and contribute to the autoinhibitory effect on RAS/MAPK signaling.