Plasmodium malariae: transmission from monkey to man by mosquito bite

Anopheles freeborni mosquitoes were infected by feeding on New World monkeys, Aotus trivirgatus, infected with a Nigerian strain of Plasmodium malariae. The infection was passed to human volunteers through the bites of these mosquitoes, demonstrating the practicability of using a simian host for infection of mosquitoes with a third species of human malaria parasite and of the use of such mosquitoes to transmit the infection from monkey to man.     

Excess polymorphisms in genes for membrane proteins in Plasmodium falciparum

The detection of single-nucleotide polymorphisms in pathogenic microorganisms has normally been carried out by trial and error. Here we show that DNA hybridization with high-density oligonucleotide arrays provides rapid and convenient detection of single-nucleotide polymorphisms in Plasmodium falciparum, despite its exceptionally high adenine-thymine (AT) content (82%). A disproportionate number of polymorphisms are found in genes encoding proteins associated with the cell membrane. These genes are targets for only 22% of the oligonucleotide probes but account for 69% of the polymorphisms. Genetic variation is also enriched in subtelomeric regions, which account for 22% of the chromosome but 76% of the polymorphisms.     

作物基因工程育种研究进展与展望

本文综述了作物基因工程育种的主要内容、应用,着重探讨了其技术体系及其在农作物的最新研究进展；并展望了基因工程在西藏作物育种中的发展前景。     

Complete development of hepatic stages of Plasmodium falciparum in vitro

An in vitro model was developed to study the hepatic phase of Plasmodium falciparum, the only malaria parasite lethal to man. Primary cultures of human hepatocytes were inoculated with sporozoites of Brazilian and African strains of P. falciparum. On days 1 through 7 after inoculation examination of fluorescence-labeled and Giemsa-stained preparations demonstrated the presence of many intracellular parasites. In three separate sets of experiments all cultures were found to be infected with as many as 650 liver schizonts measuring up to 40 micrometers. After the addition of red blood cells, intraerythrocytic forms of P. falciparum were detected on days 12 and 13 by an immunofluorescence assay, indicating that the hepatic cycle had been completed in vitro.     

水稻花粉发育相关基因的研究进展

综述了目前研究已发现的与水稻花粉发育相关的基因,包括小孢子母细胞发育、花粉囊蜡质发育、绒毡层发育、胼胝质沉积、小孢子母细胞减数分裂、雄配子发生过程、花药开裂等,并就水稻花粉基因研究的动态,阐述了今后研究的重点和方向。     

Amplification of a gene related to mammalian mdr genes in drug-resistant Plasmodium falciparum

The malaria parasite Plasmodium falciparum contains at least two genes related to the mammalian multiple drug resistance genes, and at least one of the P. falciparum genes is expressed at a higher level and is present in higher copy number in a strain that is resistant to multiple drugs than in a strain that is sensitive to the drugs.     

Diversity of circumsporozoite antigen genes from two strains of the malarial parasite Plasmodium knowlesi

The complete nucleotide sequence of the coding region of the circumsporozoite antigen gene (CS gene) of the Nuri strain of the malarial parasite Plasmodium knowlesi is presented. The gene from the Nuri strain exhibits a novel form of sequence diversity when compared to the CS gene from the H strain. Instead of the 12 tandem repeating 36-base pair units of the H strain, the Nuri strain contains 16 tandem repeating 27-base pair units of a different nucleotide sequence that encodes a different repeating peptide. In contrast, the 5' and 3' coding and noncoding sequences flanking the repeats are 98 percent conserved in both strains.     

Rationale for development of a synthetic vaccine against Plasmodium falciparum malaria

Protective immunity against malaria can be obtained by vaccination with irradiated sporozoites. The protective antigens known as circumsporozoite (CS) proteins, are polypeptides that cover the surface membrane of the parasite. The CS proteins contain species-specific immunodominant epitopes formed by tandem repeated sequences of amino acids. Here it is shown that the dominant epitope of Plasmodium falciparum is contained in the synthetic dodecapeptide Asn-Ala-Asn-Pro-Asn-Ala-Asn-Pro-Asn-Ala-Pro or (NANP)3. Monoclonal antibodies and most or all polyclonal human antibodies to the sporozoites react with (NANP)3, and polyclonal antibodies raised against the synthetic peptide (NANP)3 react with the surface of the parasite and neutralize its infectivity. Since (NANP)3 repeats are present in CS proteins of P. falciparum from many parts of the world, this epitope is a logical target for vaccine development.     

主要家畜生长发育相关基因研究进展

为从基因分子水平提高家畜生长发育性能,了解调节家畜生长发育的相关基因,提高家畜优势育种水平,综述了近年来主要家畜生长发育相关基因的研究进展,总结了当前存在的问题,也对其应用前景进行了展望。     

多胺在果树生长发育中的作用

就多胺与果树萌发、坐果、果实发育、根系形成、果树衰老的关系进行了综合评述,并对近20年来外源多胺在果树上的应用进行了分析.     

影响羊早期胚胎发育阻滞相关基因的筛选

采用单胚构建的mRNA差异显示技术,探讨经体内发育和体外培养获得的山羊8~16细胞期胚胎基因的表达情况,并从在体内发育胚胎特异表达的片段中选择1个片段进行分析。结果表明:该片段与牛肥胖基因具有86%的同源性。该基因对卵母细胞的成熟以及早期胚胎的分裂和分化具有明显的作用,可调节母体的妊娠生理,影响生殖激素的分泌,从而对克服早期胚胎发育阻滞具有重要的作用。     

江苏省多基因聚合对水稻稻瘟病抗性的效应分析及Pb1基因功能标记开发

[目的]研究多基因聚合对水稻稻瘟病抗性的效应,并开发Pb1基因功能标记,为江苏省培育持久抗稻瘟病品种及提高其育种效率提供理论依据.[方法]开发Pb1基因的功能标记,并结合Pita、Pib、Pi54、Pikm和Pizt功能标记检测2015─2017年参加江苏省预试的703份常规粳稻材料的抗病基因,分析其聚合方式与稻瘟病抗性的相关性.[结果]在Pb1基因编码区上游926~1085 bp设计1个存在/缺失标记M1,其引物可扩增获得160 bp的片段.703份供试材料中,Pita、Pib和Pi54基因频率高于Pikm、Pb1和Pizt,虽然抗病频率(稻瘟病综合指数≤5.0的材料所占比例)在2015─2017年呈逐年快速升高趋势,但3年间达中抗及以上等级的材料所占比例均较低.不含抗病基因的材料11份,综合指数≤5.0的材料4份,抗病频率为36.36%;当所含抗病基因数≤3个时,随着含抗病基因数的增加,对应的材料数量、出现频率和综合指数≤5.0的材料数量均明显增加,当所含抗病基因数≥4个时,随着含抗病基因数的增加,对应的材料数量、出现频率和综合指数≤5.0的材料数量均明显降低.抗病基因数越多,抗病频率越高,当抗病基因数达6个时,抗病频率达100.00%,说明聚合的抗病基因数与抗病频率呈正相关.3个抗病基因聚合的最佳方式为:Pi54+Pib+Pb1或Pita+Pib+Pikm.4个抗病基因聚合的最佳方式为Pita+Pib+Pikm+Pizt或Pita+Pi54+Pib+Pb1.[结论]开发的Pb1基因功能标记可应用于水稻稻瘟病抗性育种,以提高选择效率.多基因聚合能提高水稻稻瘟病抗性,但抗性强弱取决于抗性基因间的互作效应,并不是简单的累加效应.     

内毒素对鹅胚胎发育的影响

以广东省台山市2家活胚率差异明显的鹅场为对象,检测了活胚与死胚的囊胚液内毒素水平,并比较了家鹅场的受精率、活胚率与血浆内毒素水平之间的关系.结果表明,2家鹅场的活胚囊胚液中的内毒素水平均明显低于各自死胚中的内毒素(P<0.05),但鹅场间的活胚或死胚内毒素水平均无显著差异:活胚率明显高的鹅场.其血浆内毒素水平显著低于活胚率低的鹅场(P<0.05),受精率在2家鹅场间则无显著差异.从而证明,种鹅生产中内毒素能明显影响胚胎的成活率.     

PDX-1基因对人胚肾细胞胰岛发育相关基因表达的影响

【目的】研究人PDX-1基因对胰岛发育相关基因和胰岛素基因(Insulin,INS)表达的影响,探讨PDX-1基因诱导非β细胞为胰岛素分泌细胞的可能性。【方法】采用PCR扩增技术,从人的胰腺cDNA中扩增PDX-1基因和INS基因的阅读框架,分别构建了质粒pAAV-PDX-1和pAAV-INS;将pAAV-PDX-1转染人胚肾细胞(293T)48 h后,RT-PCR检测293T细胞中胰岛发育相关基因的表达;再将pAAV-PDX-1和pAAV-INS共转染293T细胞48 h后,RT-PCR检测293T细胞中INS的表达。【结果】转染pAAV-PDX-1的293T细胞中,检测到胰岛发育相关基因PDX-1、Ngn3、PC2、BETA2的表达;PDX-1没有直接增强INS基因表达的作用。【结论】在293T细胞中,PDX-1基因对胰岛发育相关基因的表达有重要影响,PDX-1在诱导非β细胞为胰岛素分泌细胞的过程中可能有着重要的作用。     

牛磺酸对断奶小鼠小肠发育的影响

为研究牛磺酸对断奶小鼠小肠结构和功能的影响,采用单因子设计,48只体重为(12±2)g的昆明小鼠随机分为6组,每组8只,雌雄各半,分为对照组和试验组,对照组饮用普通自来水,试验组在饮水中添加2.5、5.0、10.0、20.0和40.0g/L牛磺酸,试验期31d。观察牛磺酸对小肠和肝脏重量,空肠绒毛形态、细胞凋亡、小肠核酸和蛋白质含量,以及血清指标的影响。结果表明:1)饮水中添加牛磺酸可显著提高小鼠小肠绝对重量和相对重量(P0.05),且呈现二次曲线关系(PQ0.05);可线性提高小肠绝对长度、肝脏绝对重量和相对重量(PL0.05)。2)2.5、5.0和10.0g/L组与对照组相比,显著降低空肠肠腺(肠隐窝)深度(P0.05);回肠Prot/DNA随牛磺酸添加量提高而线性提高(PL0.05)。3)与对照组比较,5.0g/L添加组的细胞凋亡指数显著降低(P0.05),但40g/L添加组有升高的趋势。4)随着牛磺酸添加量的提高,回肠MDA含量有降低的趋势(P=0.07),空肠GSHPx呈现先升高再降低的二次曲线关系(PQ0.05),但不影响血清IGF-I水平。研究结果表明,饮水添加中低浓度的牛磺酸可提高小鼠小肠长度和重量,降低肠隐窝深度,减少细胞凋亡。     

盘式蚊香中氯氟醚检测方法研究

以邻苯二甲酸二戊酯为内标物,用气相色谱法测定盘式蚊香中氯氟醚的含量.样品经粉碎机粉碎处理,过标准分析筛,有机溶剂萃取后,通过HP-5毛细管柱分离,氢火焰离子化检测器检测,测得某品牌盘式蚊香中氯氟醚的含量为0.082%,加标回收率99.7%～106.2%,相对标准偏差2.0%.该方法可对不同品牌盘式蚊香进行测定.