山羊毛虱的形态结构和分子标志研究

为了解山羊毛虱形态结构和分子标志,用电子显微镜和三维立体显微镜观察了采自山羊的山羊毛虱形态结构,测定了其18SrDNA和cox1基因序列,并基于比对,揭示其序列特点。形态观察发现,触角3节,第1节短粗,第2、3节细长;中胸气门1对,位于前胸两侧;腹部有气门6对;跗节3节。序列分析显示,本样虱、山羊毛虱、具边毛虱和牛毛虱四者的18SrDNA基因序列高度相似,不适于做种间鉴定。cox1序列极不保守。     

Molecular evidence for cosmopolitan distribution of platyhelminth parasites of tunas (Thunnus spp.)

Global distribution of platyhelminth parasites and their host specificities are not well known. Our hypothesis was that platyhelminth parasites of large pelagic fishes are common around the world. We analysed molecular variation in three different taxa of platyhelminth parasites infecting four species of tunas: yellowfin tuna (Thunnus albacares, Scombridae) from Western Australia, southern bluefin tuna (Thunnus maccoyii, Scombridae) from South Australia, Pacific bluefin tuna (Thunnus orientalis, Scombridae) from Pacific Mexico and northern bluefin tuna (T. thynnus, Scombridae) from two localities in the Mediterranean (Spain and Croatia). Comparisons of ITS2 and partial 28S rDNA demonstrated two congeneric species of blood flukes (Digenea: Sanguinicolidae) from multiple hosts and localities: Cardicola forsteri from southern bluefin and northern bluefin tunas, and Cardicola sp. from Pacific bluefin and northern bluefin tunas; and a gill fluke, Hexostoma thynni (Polyopisthocotylea: Hexostomatidae), from yellowfin, southern bluefin and northern bluefin tunas. Partial 28S rDNA indicates that a second type of fluke on the gills, Capsala sp. (Monopisthocotylea: Capsalidae), occurs on both southern bluefin and Pacific bluefin tunas. This appears to be the first report of conspecific platyhelminth parasites of teleosts with a wide‐ranging geographical distribution that has been confirmed through molecular approaches. Given the brevity of the free‐living larval stage of both taxa of flukes on the gills (H. thynni and Capsala sp.), we conclude that the only feasible hypothesis for the cosmopolitan distribution of these flatworms is migrations of host tunas. Host migration also seems likely to be responsible for the widespread occurrence of the two species of blood flukes (Cardicola spp.), although it is also possible that these were translocated recently by the spread of infected intermediate hosts.     

β-甘露聚糖酶基因重组整合组成型表达载体的构建

应用PCR方法从P.pastorisGS115染色体中扩增了GAP启动子(PGAP),大小为500bp左右,以其取代诱导型表达载体pPIC9K上的AOX1启动子(PAOX1),构建了组成型表达载体pGAP;再从野生型酵母菌JSY4染色体中扩增出25S rDNA保守序列,大小为1 700bp左右,以其取代组成型表达pGAP上的组氨酸脱氢酶基因(H IS4)片断,构建了整合组成型表达载体pGAP-rDNA。再双酶切重组质粒pT002M anⅠ得编码β-甘露聚糖酶的ManⅠ基因片断插入pGAP-rDNA的多克隆位点(MCS),获得含有目的基因ManⅠ的重组整合组成型表达载体pGAP-rDNA-ManⅠ。CaC l2法转化感受态大肠杆菌DH5α,对阳性克隆进行质粒PCR鉴定和单、双酶切鉴定。结果表明:成功构建了重组组成型表达载体pGAP-rDNA-ManⅠ,为下一步野生型酵母菌JSY4中β-甘露聚糖酶的组成型表达打下基础。     

甘肃省定西市当归“水烂病”病原鉴定及致病性测定

水烂病是甘肃省当归上发生的一种病害.本试验对水烂病病原菌的形态特征、培养特性、生理生化指标进行了测定,同时结合16SrDNA序列测定和相似性比对,发现该病原菌与GenBank数据库已知荧光假单胞杆菌第2生物型(Pseudornonas fluorescens生物型Ⅱ)的序列相似性达99％,其片段大小为1445 bp,编号为ZB1.致病性测定结果表明,该病原菌对‘岷归2号’(新繁品种)致病力最强,‘岷归1号’(主栽品种)次之,对‘朝鲜当归’(引进品种)的致病力最弱.本研究首次报道了荧光假单胞杆菌第2生物型能引起当归水烂病.     

斑点叉尾鲴嗜麦芽寡养单胞菌的分离鉴定及系统发育分析

从发生在四川、重庆等省市的斑点叉尾妇急性流行性传染病病鱼的肝脏、肾脏内分离到1株高致病性菌株（CCF00024），人工感染健康鱼表现出与自然痛鱼相同的症状，并从中分离获得同种细菌，证实其为斑点叉尾鲴急性流行性传染病的病原菌。形态、生理生化检测表明，该菌为非发酵型直杆菌，严格需氧，革兰氏阴性，极生多鞭毛，对除麦芽糖和甘露糖以外的多种糖类不利用产酸，氧化酶阴性，DNA酶、蛋白酶、脲酶、赖氨酸脱羧酶阳性，MR、VP阴性。在以该菌16SrDNA序列（GenBank登录号AY970826）和GenBank及RDP数据库内同源性较高的细菌16SrDNA序列构建的系统发育树中，分离菌CCF00024与嗜麦芽寡养单胞菌（Stenotrophomonasmaltophilia）聚在一簇，特剐是与5．maltophiliaM5—1的同源性最高，序列相似性达99．6％，结合形态和生理生化特点将其鉴定为嗜麦芽寡养单胞菌（Stenotrophomonasmaltophilia）。药敏试验结果表明，对磺胺甲口恶唑、磺胺异口恶唑、阿齐霉素、洛美沙星高度敏感，而对新霉素、卡那霉素、氨苄青霉素、头孢唑啉、先锋霉素V和链霉素不敏感。     

Sequence and Phylogenetic Analysis of rDNA ITS of Three Eimeria Species in Rabbit

In order to study whether the internal transcribed spacers (ITS) sequence could be used as a molecular marker for the species identification of rabbit coccidian, the rDNA ITS of Eimeria intestinalis, Eimeria flavescens and Eimeria magna were amplified by polymerase chain reaction (PCR), and were cloned into pGEM-T Easy vector subsequently. The positive recombinant plasmids were identified by PCR and then sequenced. By sequence comparison and comparative analysis with the relative sequences of rabbit Eimeria spp. available in GenBank, the results showed that the lengths of Eimeria intestinalis, Eimeria flavescens and Eimeria magna were 1065, 1009 and 1047 bp, respectively, and the sequence homologies with the same species sequences were 99.2%, 99.0% and 94.5%, respectively, while were 55.3% to 82.1% compared with corresponding sequences of other different species sequences. The phylogenetic analysis using software Mega 5.0 showed that all rabbit coccidia clustered together in a clade, which was divided into two sister lineages, corresponding to the presence or absence of oocyst residuum. The result demonstrated ITS could be used as a molecular marker for the species identification of rabbit coccidia.     

长牡蛎食物组成的高通量测序分析

为了更加细致地甄别滤食性贝类的食物组成,于2019年8月,以北方规模化典型养殖海湾——桑沟湾养殖的长牡蛎(Crassostrea gigas)为研究对象,运用Illumina高通量测序技术对长牡蛎的胃含物及所处养殖水体中的真核生物进行分析研究.结果显示,扩增18S rDNA V4区平均得到111,359个有效序列短片段...     

Genetic characteristics of Streptococcus dysgalactiae isolated from cage cultured cobia,Rachycentron canadum (L.)

Disease outbreaks occurred during 2007–2013 in Taiwan with 2.5–10% mortality among the cage cultured cobia, Rachycentron canadum (L.), characterized by the presence of polyserositis, pericarditis and peritonitis. The micro‐organisms isolated from internal organs were Gram‐positive cocci. The isolates were confirmed as Streptococcus dysgalactiae by a polymerase chain reaction assay that yielded the expected specific 259 bp amplicon. Additionally, partial sequence of the 16S–23S rDNA intergenic spacer region of the GCS strain isolates from fish was also compared and produced 100% sequence identity with S. dysgalactiae (GenBank accession number AB252398 ). The genetic characterization was then determined by pulsed‐field gel electrophoresis (PFGE) analysis. Based on PFGE, the Apa I or Sma I digestion patterns of chromosomal DNA of these isolates were grouped into three main clusters. Taiwanese strains were divided into two clusters, and the tet(M) gene was detected in cluster 1 (pulsotypes: A1–A2 and S1–S3), but not in cluster 2 strains (pulsotypes: A3–A4 and S4–S5). Three Japanese strains from amberjack, Seriola dumerili (Risso), were grouped into cluster 3 (pulsotypes: A5–A7 and S6–S8) and displayed no mortality to cobia in the challenge experiment. Conversely, Taiwanese strains from cobia and snubnose pompano, Trachinotus blochii (L.), displayed a mortality rate of 50–87.5% in cobia.     

库姆塔格沙漠北界阿奇克谷地土壤可培养细菌多样性

为明确库姆塔格沙漠北界阿奇克谷地的土壤细菌多样性,探索该地区土壤微生物与植物群落的相互作用关系,采用NA、R2A培养基分离培养土壤细菌,通过16S rDNA序列系统发育分析鉴定菌株。结果表明,R2A平板菌落数量和种类较多;发现13株潜在新种菌株,已知菌种分属3大类群、4属、20种,厚壁菌门(Firmicutes)为优势类群,芽胞杆菌属(Bacillus)为优势属,枯草芽胞杆菌(Bacillus subtilis subsp.inaquosorum)为优势菌种。与其他类似环境相比,阿奇克谷地土壤中可培养细菌生物量偏小,可培养的细菌多为抗性、耐性强的极端微生物。该地区特有的微生物资源、功能微生物和新菌资源丰富,为防沙治沙、微生物菌剂开发等研究提供物质基础。本研究结果对库姆塔格沙漠的自然生态保护以及极端环境微生物资源的应用具有重要意义。