Prenatal diagnosis of severe combined immunodeficiency with defective synthesis of HLA molecules

The immunodeficiency associated with a defective expression of HLA molecules is an autosomal recessive disorder leading to death during childhood. We have performed prenatal diagnosis for six fetuses at risk for this disease by membrane immunofluorescence on blood lymphocytes and monocytes, using specific monoclonal antibodies for HLA class I and II molecules. Two pregnancies have been found to be affected. The diagnosis has been confirmed on each abortus by the study of the membrane expression of HLA class I and II molecules on blood lymphocytes and monocytes, and on thymic and splenic cells. The four other cases were found to be normal both during pregnancy and after birth. The detection of the defect as early as the 20th week of gestation allows selective termination.     

低温1,2,4-TCB降解菌的选育、降解特性及邻苯二酚1,2-双加氧酶基因表达水平

从长期受1,2,4-三氯苯(1,2,4-TCB)污染的地下水中筛选出一株低温寡营养降解菌A2,对A2菌进行革兰氏染色鉴定和16S rDNA鉴定,研究了不同pH、温度、盐度等因素对A2菌降解1,2,4-TCB效果以及对邻苯二酚1,2-双加氧酶基因表达的影响,并进行了正交实验。结果表明,A2菌为革兰氏阴性短杆细菌,初步鉴定为假单胞菌;在pH值为7、培养温度30℃、盐度0.8%、培养时间6 d时,A2菌对1,2,4-TCB降解效果最好,降解率达到88.14%,同时该条件下邻苯二酚1,2-双加氧酶基因相对表达水平最高;培养温度为10℃时,A2菌对1,2,4-TCB降解率可达到85.3%,同时邻苯二酚1,2-双加氧酶基因也有较高的相对表达水平。以上结果说明,将A2菌应用于低温寡营养地下水的生物修复是可能的。     

Identification and comprehensive evaluation of a novel biocontrol agent Bacillus atrophaeus JZB120050

Abstract

Bacillus spp. have long been used as biocontrol agents because of their efficient broad-spectrum antimicrobial activity. We identified a novel strain of Bacillus atrophaeus, named JZB120050, from soil. B. atrophaeus JZB120050 had a strong inhibitory effect against Botrytis cinerea and many other phytopathogens. Gas chromatography-mass spectrometry showed that B. atrophaeus JZB120050 produced many secondary metabolites, such as alkanes, alkenes and acids; some of which were related to pathogen inhibition. Enzyme activity analysis showed that B. atrophaeus JZB120050 secreted cell-wall-degrading enzymes, including chitinase, glucanase and protease, which degraded fungal cell walls. Both the novel glucanase gene bglu and chitinase gene chit1 were cloned and heterologously expressed in Escherichia coli and the products showed strong enzyme activity. In addition, B. atrophaeus JZB120050 secreted siderophores and formed a significant biofilm. Future studies should focus on these antimicrobial factors to facilitate widespread application in the field of agricultural biocontrol.     

基因芯片筛选氯化汞对大鼠脑神经毒性差异表达基因

为了筛选汞神经毒性差异表达基因和探讨汞神经毒性分子机制,采用基因芯片技术,研究了大鼠皮下注射0.5mg/kg的HgCl₂ 1h后脑中基因表达的变化.结果表明,基因表达谱中差异表达基因共有742条,上调基因562条,下调基因180条.生物信息学分析表明,差异表达基因中有免疫应答及解毒作用相关基因、遗传信息传递与表达相关基因、细胞信号传导基因、神经传导基因、细胞增殖与分化基因、细胞调亡等多种基因.分析结果提示这些基因的差异表达可能与汞神经毒性有关.利用基因芯片技术筛选相关基因,为深入阐明汞神经毒性的作用机制提供了新思路.     

宏转录组学在环境微生物生态学中的应用

系统总结了宏转录组学实验操作及数据分析流程,概述了宏转录组学在环境微生物生态学的研究策略和最新进展,并指出其应用前景.宏转录组学在解析环境微生物群落功能上具有广阔的前景,为了解微生物群落的动态演化及其与环境因素和生态系统功能的关系提供了强有力的工具.     

甲基汞对大鼠脑即刻早期基因c-jun mRNA表达影响

为了探讨甲基汞神经毒性早期预报指标和信息传递分子机制,本文应用RT-PCR方法研究了不同浓度甲基汞暴露不同时间后,大鼠脑中即刻早期基因c-jun mRNA表达变化(对照组为0.9%生理盐水、暴露组浓度分别为0.05、0.5、5 mg·kg^-1;取样时间分别为20、60、240、1440 min).结果表明大鼠脑c-jun mRNA表达优先于汞的蓄积,大鼠脑c-jun mRNA表达变化对于甲基汞神经毒性具有早期预报作用, 即刻早期基因c-jun参与了甲基汞对中枢神经系统损害的毒性过程.     

H_2O_2诱导拟南芥NIT2基因甲基化特征与转录水平改变

用外源H2O2处理拟南芥植株,亚硫酸氢盐修饰后测序法分析胁迫生理中NIT2基因启动子区甲基化特征变化,RT-PCR检测该基因的转录水平.结果显示:用100#mol·L-1的H2O2处理3 h后,NIT2启动子区胞嘧啶总甲基化水平与对照差异不大,但对照组CHG(H为C、A或T)和CG位点甲基化水平分别为35.0%和93.3%,H2O2处理组CHG和CG位点甲基化水平分别为50.0%和96.9%;H2O2处理组CHH位点则表现为甲基化水平升高、降低或去甲基化;H2O2胁迫组拟南芥地上组织中NIT2基因转录水平提高.研究结果表明:NIT2基因的转录应答和DNA甲基化修饰参与了植株的逆境生理过程;氧化胁迫与DNA甲基化改变、基因转录上调同时发生,说明胁迫诱发的活性氧增高可能参与胞嘧啶甲基化修饰和基因转录的调节.     

多菌灵对泥鳅肝脏典型生物标志物的影响及其可逆性分析

多菌灵(carbendazim, BCM)作为一种常用的广谱性杀菌剂,可通过地表径流汇入周边水域,对水生生物存在潜在威胁。为探究BCM对水生生物的毒性效应,以泥鳅(Misgurnus anguillicaudatus)为受试动物,采用半静态亚急性毒性法分别检测4个BCM浓度(0.020、0.075、0.282和1.060 mg·L^-1)胁迫10、20、30 d时其肝脏丙二醛(malondialdehyde, MDA)和8-羟基脱氧鸟苷(8-hydroxy-2 deoxyguanosine, 8-OHdG)含量、超氧化物歧化酶(superoxide dismutase, SOD)和过氧化氢酶(catalase, CAT)活性、7-乙氧基-3-异吩恶唑酮-脱乙基酶(7-ethoxy-3-isophenoxazolone deethylase, EROD)和谷胱甘肽巯基转移酶(glutathione S-transferase, GST)活性、Cu/Zn-sod、cat3、cyp1a1和gst基因mRNA表达量,随后在自然水体恢复驯养30 d时进行再检测,运用综合生物标志物指数(integrated biomarker response, IBR)对BCM毒性效应进行综合评价。结果显示,BCM胁迫下泥鳅肝脏MDA含量在胁迫中后期持续上升,恢复期仍显著增加,高浓度组毒性效应显著,8-OHdG含量在暴露周期内、恢复期均受到积极诱导;SOD活性与Cu/Zn-sod表达量在暴露前期受到显著诱导,CAT活性受到明显抑制作用而cat3表达量呈显著上升趋势,恢复期抗氧化酶活性均受到显著诱导,抗氧化酶活性与其表达量表达并不完全一致;EROD活性与cyp1a1基因表达量在短时间暴露受到诱导,而长期暴露及恢复期均受到不同程度抑制,GST活性与gst表达量在暴露期均受到明显诱导,随着时间延长诱导作用减弱,但恢复期受到明显抑制;IBR指数与BCM胁迫时间及浓度存在显著正相关,恢复期IBR指数略有下降但毒性损伤效应仍显著存在。综上,一定剂量的BCM胁迫会对抗氧化酶系和代谢解毒酶系造成严重损伤,肝脏综合毒性效应明显,具有一定生物毒性,进行短期恢复驯养机体损伤出现一定程度可逆性,但并未恢复至正常水平,因此BCM污染应得到广泛关注。