一株农药降解生防细菌的分离与鉴定

从花生根际土壤中分离到一株对多种土传植物病原真菌具有拮抗作用的生防细菌B3, 该菌能够以100 mg/L高效氯氰菊酯、毒死蜱和吡虫啉为唯一碳源生长, 7 d的降解率分别为54.42%、57.44%和49.24%, 显示了该菌在植物病害生物防治和土壤生物修复方面具有潜在的开发价值。通过形态特征、生理生化及16S rRNA同源性序列分析, 鉴定该菌为多粘类芽孢杆菌(Paenibacillus polymyxa)。     

向日葵菌核病拮抗菌XRK5的筛选与鉴定

从向日葵根际分离了640个细菌分离物,以向日葵菌核病菌(Sclerotinia sclerotiorum)为靶标菌,通过平板对峙法获得了18个具有拮抗性能的细菌,其中XRK5具有较强拮抗能力,且拮抗性能稳定,具有较好的生防应用潜力。经过形态观察、生理生化特征及16SrRNA序列分析,将XRK5鉴定为辣椒溶杆菌(Lysobacter capsici),XRK5的16SrRNA序列在GenBank中的注册号为FJ959348。     

两株棉花立枯病拮抗菌MH1和MH25的筛选与鉴定

从棉花根际分离了1277个细菌分离物, 以棉花立枯病病原真菌立枯丝核菌(Rhizoctonia solani Kuhn)为靶标菌, 通过平板对峙法获得25个具有拮抗性能的分离物, 其中MH1和MH25具有较强的拮抗性能, 且拮抗性能稳定, 具有较好的生防潜力。经过形态观察、生理生化特征分析及16S rDNA序列分析, MH1为短芽孢杆菌(Brevibacillus brevis), MH25为枯草芽孢杆菌(Bacillus subtilis)。MH1和MH25的16S rDNA序列在GenBank中注册号分别为: EF488102, EF488103。     

一株蛋白酶产生菌的分离鉴定

目的:对喀什市吐曼河分离的一株细菌进行鉴定.方法:基于生理生化实验和16S rRNA序列分析.结果:该分离菌G-,球状,需盐但不耐盐,pH耐受范围是pH 6.2～7.8,产蛋白酶且粗酶酶活达168U/ml.16S rRNA序列分析表明,该细菌与类产碱假单胞菌(P.pseudoalcaligenes)16 rSNA序列有100%的相似性.结论:初步推断该细菌属于Pseudomonas属.     

高寒草地珠芽蓼内生拮抗固氮菌Z19的鉴定及其固氮功能

【目的】从东祁连山高寒草地珠芽蓼内生细菌中筛选和鉴定具有固氮能力和拮抗能力的内生细菌。【方法】采用16S rRNA基因序列同源性分析和生理生化指标测定方法对该菌株进行鉴定。【结果】从珠芽蓼中分离获得的21株内生细菌中6株内生菌具有固氮能力,76.2%具有抑菌能力,其中5株内生细菌对5种以上的病原菌有抑制作用;菌株Z19具有较强固氮能力和分解纤维素的能力,其纤维素溶解圈直径与菌落直径比达3.33,产生的纤维素酶活性为0.31 U,且对辣椒立枯丝核病菌(Rhizoctonia solani)、油菜菌核病菌(Sclerotinia sclerotiorum)、番茄灰霉病菌(Botrytis cinerea)、小麦根腐病菌(Bipolaris sorokiniana)和番茄早疫病菌(Alternaria solani)具有较强拮抗能力;经PCR扩增和测序,获得了菌株Z19的固氮基因(nifH)序列和16S rRNA基因序列,在GenBank中的登录号分别为EU693340和EU236746;菌株Z19呈革兰氏阳性,杆状,产芽孢。【结论】结合生理生化特征及16S rRNA基因序列同源性比较,鉴定其为枯草芽孢杆菌(Bacillus subtilis)。     

两株棉花立枯病拮抗菌MH1和MH25的筛选与鉴定

从棉花根际分离了1277个细菌分离物,以棉花立枯病病原真菌立枯丝核菌(Rhizoctonia solani Kuhn)为靶标菌,通过平板对峙法获得25个具有拮抗性能的分离物,其中MH1和MH25具有较强的拮抗性能,且拮抗性能稳定,具有较好的生防潜力.经过形态观察、生理生化特征分析及16S rDNA序列分析,MH1为短芽孢杆菌(Brevibacillus brevis),MH25为枯草芽孢杆菌(Bacillus subtilis).MH1和MH25的16S rDNA序列在GenBank中注册号分别为:EF488102,EF488103.     

盐地碱蓬内生中度嗜盐菌的分离与系统发育多样性分析

为了了解东营滨海盐地碱蓬植株内生中度嗜盐菌的多样性,采用传统分离鉴定技术和基于16S rRNA序列分析对样品中可培养细菌的多样性进行研究。根据其生理生化特征、16S rRNA序列测定和系统发育分析,分离获得的15株内生菌可分为4个类群,涉及Halomonadaceae科的Chromohalobacter属、Kushneria属、Halomonas属以及Bacillaceae科的Bacillus属。类群I中4菌株的16S rRNA序列与Chromohalobacter israelensis的最高相似性为95%。类群II共7株菌,归属于Kushneria属,是碱蓬内生中度嗜盐菌中的优势类群。类群III菌株的16S rRNA序列与一株尚无明确分类地位的Gammaproteobacteria亚门耐盐固氮细菌Haererehalobacter sp.JG11的相似性为99%。类群IV中的芽孢杆菌的16S rRNA序列与已知细菌的相似性为96%,很可能代表了Bacillus属的新种。各种水解酶类的分析表明,在分离的15株菌中有3株菌产蛋白酶,14株产酯酶,8株产DNA酶,11株产半乳糖苷酶,14株产脲酶。研究结果揭示,盐地碱蓬中存在较为丰富的中度嗜盐菌多样性和系统发育多样性,并且潜藏着较多的新的微生物类群。     

黄鳝病原性维氏气单胞菌温和生物变种的分离与鉴定

从养殖患出血病黄鳝(Monopterus albus)的肝脾肾中分离到大量菌落形态和色泽一致的细菌。16S rRNA序列分析证实随机挑选的5个分离株为同一种细菌,其中一株编号为HS120920进一步鉴定。结合细菌的形态特征,生理生化特征及16S rRNA和gyrB序列分析结果,鉴定该菌为维氏气单胞菌温和生物变种(Aeromonas veronii biovar sobria)。该菌对黄鳝的半致死浓度约为5.79×107 CFU/mL。药敏试验结果显示,菌HS120920对7种喹诺酮类,5种氨基糖苷类等17种抗菌药物高度敏感,对其他3种抗菌药物低敏,或有抗性。     

一株产淀粉酶芽胞杆菌SY200的鉴定及其对动物病原菌的生物拮抗试验

目的对一株产淀粉酶芽胞杆菌SY200进行鉴定及其对动物病原菌的生物拮抗试验。方法提取芽胞杆菌SY200基因组DNA,采用细菌16S rRNA通用引物进行PCR扩增及对扩增到的目标片段的测序,将测序结果与NCBI上已知菌种的16S rRNA序列进行BLAST对比,并构建系统进化树进行分析。采用滤纸片法和牛津杯法分别研究该芽胞杆菌的全菌液及培养物上清液对3株病原菌的生物拮抗。结果结合细菌形态观察及生理生化特性鉴定,最终确定菌株SY200为甲基营养型芽胞杆菌(Bacillus methylotrophicus);芽胞杆菌SY200全菌培养液和培养上清液对产肠毒素大肠埃希菌、鸡白痢沙门菌、金黄色葡萄球菌均有较强的生物拮抗作用,抑菌物质主要为细菌的代谢产物。结论芽胞杆菌SY200被鉴定为甲基营养型芽胞杆菌,该菌株对3株动物性病原菌具有较强的生物拮抗作用。     

Viili乳制品中干酪乳杆菌的分离鉴定

从引进Viili乳制品中筛选、鉴定出3种优良乳酸菌。采用平板分离法从Viili乳制品中分离3株乳酸菌,通过表型1、6S rRNA的PCR扩增、克隆、测序鉴定。3株乳酸菌的表型鉴定结果符合伯杰细菌鉴定手册中乳杆菌属的干酪乳杆菌,16S rRNA序列同源性分析结果表明3株分离菌与干酪乳杆菌的同源性分别为99.93%、100.00%9、9.78%,从Viili乳制品分离到3株干酪乳杆菌。     

Identification of Escherichia coli through analysis of 16S rRNA and 16S-23S rRNA internal transcribed spacer region sequences

A bacterial strain, designated BzDS03 was isolated from water sample, collected from Dal Lake Srinagar. The strain was characterized by using 16S ribosomal RNA gene and 16S-23S rRNA internal transcribed spacer region sequences. Phylogenetic analysis showed that 16S rRNA sequence of the isolate formed a monophyletic clade with genera Escherichia. The closest phylogenetic relative was Escherichia coli with 99% 16S rRNA gene sequence similarity. The result of Ribosomal database project's classifier tool revealed that the strain BzDS03 belongs to genera Escherichia.16S rRNA sequence of isolate was deposited in GenBank with accession number FJ961336. Further analysis of 16S-23S rRNA sequence of isolate confirms that the identified strain BzDS03 be assigned as the type strain of Escherichia coli with 98% 16S-23S rRNA sequence similarity. The GenBank accession number allotted for 16S-23S rRNA intergenic spacer sequence of isolate is FJ961337.     

日本囊对虾4个地理群体线粒体16S rRNA序列及遗传结构分析

对我国东南沿海日本囊对虾(Marsupenaeus japonicus)的4个地理群体广东群体(GD)、台湾群体(TW)、福建群体(FJ)和浙江群体(ZJ)的线粒体16S rRNA基因片段进行PCR扩增,对产物进行测序后分析。经比对获得470bp的核苷酸分析序列,发现了16个变异位点,得到了10种单倍型。广东、台湾、福建和浙江群体的核苷酸多样性依次分别为0.0008、0.0010、0.0051、0.0015,各群体均存在独有的单倍型和共有单倍型。群体遗传距离分析表明各群体间保持着一定的遗传差异,其中福建群体与其他群体之间存在着较远的遗传距离并保持了较高的遗传多样性。另外,利用其423bp的16S rRNA同源序列探讨了对虾科6个属共12种对虾的系统进化关系,囊对虾属与沟对虾属亲缘关系较近聚为一支,其他4个属的10种对虾聚为一支。     

新疆棉花黄萎病菌拮抗细菌的分离、筛选与鉴定

【背景】棉花黄萎病是由大丽轮枝菌(Verticillium dahliae Kleb.)引起的一种世界性病害,近年来对该病害的生物防治因具有环境友好和人畜安全的特性而倍受关注。【目的】筛选棉花黄萎病高效拮抗细菌并对其进行鉴定,为棉花黄萎病的生物防治扩充菌种资源。【方法】采用稀释涂布平板法分离细菌,并进行拮抗细菌的初筛和复筛,通过形态特征、生理生化特征和16S rRNA基因序列分析对筛选到的细菌进行鉴定,确定其分类地位。【结果】初筛分离到535株对病原菌具有拮抗作用的细菌,并选取了108株拮抗细菌进行复筛,最终筛选到了4株优势拮抗细菌。通过形态观察、生理生化特征和16SrRNA基因序列分析,将菌株BHZ-29、SHT-15、SHZ-24和SMT-24分别鉴定为贝莱斯芽孢杆菌(Bacillusvelezensis)、枯草芽孢杆菌斯皮兹仁亚种(Bacillus subtilis subsp. spizizenii)、萎缩芽孢杆菌(Bacillus atrophaeus)和香草芽孢杆菌(Bacillus vanillea)。【结论】获得了4株高效拮抗细菌,并且首次报道了香草芽孢杆菌对棉花黄萎病菌具有抑制作用。     

Identification of Comamonas species using 16S rRNA gene sequence

A bacterial strain Bz02 was isolated from a water sample collected from river Gomti at the Indian city of Lucknow. We characterized the strain using 16S rRNA sequence. Phylogenetic analysis showed that the strain formed a monophyletic clade with members of the genus Comamonas. The closest phylogenetic relative was Comamonas testosteroni with 95% 16S rRNA gene sequence similarity. It is proposed that the identified strain Bz02 be assigned as the type strain of a species of the genus Comamonas (Comamonas sp Bz02) based on 16S rRNA gene sequence search in Ribosomal Database Project, small subunit rRNA and large subunit rRNA databases together with the phylogenetic tree analysis. The sequence is deposted in GenBank with the accession number {"type":"entrez-nucleotide","attrs":{"text":"FJ211417","term_id":"209164434"}}FJ211417.     

Sulfate-reducing Bacteria and Mercury Methylation in the Water Column of the Lake 658 of the Experimental Lake Area

Sulfate-reducing bacteria (SRB) appear to be the main mediators of mercury methylation in sediments, which are deemed to be major sites of methylmercury (MMHg) production. However, recent studies have also found significant MMHg formation in the water column of lakes across North America. To investigate the potential involvement of SRB in mercury methylation in the water column of a stratified oligotrophic lake, two of the main families of SRB (Desulfobacteraceae and Desulfovibrionaceae) were quantified by Real-Time Polymerase Chain Reaction of the 16S rRNA gene. MMHg production was measured applying a stable isotope technique using ¹⁹⁸HgCl. Methylation assays were conducted at different water depths and under stimulation with lactate, acetate or propionate and inhibition with molybdate. Desulfobacteraceae and Desulfovibrionaceae16S rRNA gene copies in control samples accounted for 0.05% to 33% and <0.01% to 1.12% of the total bacterial 16S rRNA, respectively. MMHg formation was as high as 0.3 ng L^?1 day^?1 and largest in lactate amended samples. Strain isolation was only achieved in lactate amended media with all isolated strains being SRB belonging to the Desulfovibrio genus according to their 16S rRNA gene sequence. Isolated strains methylated between 0.06 and 0.2% of ¹⁹⁸HgCl per day. Acetate and propionate did not stimulate mercury methylation as much as lactate. Two strains were identified as Desulfovibrio sp. 12ML1 (FJ865472) and Desulfovibrio sp. 12ML3 (FJ865473), based on partial sequences of their 16S rRNA and DSR gene. Methylation assays and bacteria characterization suggest that Desulfovibrionaceae is an important mercury methylators in Lake 658. Supplemental materials are available for this article. Go to the publisher's online edition of Geomicrobiology Journal to view the free supplemental file.     

Neoscardovia arbecensis gen. nov., sp. nov., isolated from porcine slurries

Three Gram-positive, anaerobic, pleomorphic strains (PG10(T), PG18 and PG22), were selected among five strains isolated from pig slurries while searching for host specific bifidobacteria to track the source of fecal pollution in water. Analysis of the 16S rRNA gene sequence showed a maximum identity of 94% to various species of the family Bifidobacteriaceae. However, phylogenetic analyses of 16S rRNA and HSP60 gene sequences revealed a closer relationship of these strains to members of the recently described Aeriscardovia, Parascardovia and Scardovia genera, than to other Bifidobacterium species. The names Neoscardovia gen. nov. and Neoscardovia arbecensis sp. nov. are proposed for a new genus and for the first species belonging to this genus, respectively, and for which PG10(T) (CECT 8111(T), DSM 25737(T)) was designated as the type strain. This new species should be placed in the Bifidobacteriaceae family within the class Actinobacteria, with Aeriscardovia aeriphila being the closest relative. The prevailing cellular fatty acids were C(16:0) and C(18:1)ω9c, and the major polar lipids consisted of a variety of glycolipids, diphosphatidyl glycerol, two unidentified phospholipids, and phosphatidyl glycerol. The peptidoglycan structure was A1γmeso-Dpm-direct. The GenBank accession numbers for the 16S rRNA gene and HSP60 gene sequences of strains PG10(T), PG18 and PG22 are JF519691, JF519693, JQ767128 and JQ767130, JQ767131, JQ767133, respectively.     

Transmission of the Phytoplasma Associated with Bunchy Top Symptom of Papaya by Empoasca papayae Oman

Transmission tests were conducted with field‐collected Bunchy Top Symptoms (BTS) phytoplasma‐infected specimens of Empoasca papayae. BTS developed in all eight inoculated papayas 3 months later. The BTS phytoplasma was identified in six of eight inoculated papayas, whose partial 16S rRNA sequence (GenBank Accession no. FJ6492000 ) was 99.9% identical with those from the collected papayas (GenBank Accession no FJ649198 ) and E. papayae (GenBank Accession no. FJ649199 ), all of which are members of group 16SrII, ‘Candidatus Phytoplasma aurantifolia’. Results confirmed the ability of E. papayae to transmit the BTS phytoplasma.     

一株蜂粮源拮抗细菌的分离鉴定及其抑菌物质特性

【目的】为发掘和利用蜂粮中拮抗菌资源,对分离获得的拮抗细菌菌株PC2进行分类鉴定,并测定其发酵液抑菌物质基本特性。【方法】采用改良牛津杯双层平板法测定菌株发酵液抑菌谱及温度、p H、紫外线和蛋白酶对其抑菌活性稳定性的影响,菌株鉴定结合形态学、生理生化特征和16S r RNA基因序列分析,硫酸铵沉淀法和盐酸沉淀有机溶剂提取法进行抑菌活性物质的初步分离。【结果】从3种蜂粮中分离筛选得到17株拮抗菌株,其中1株细菌PC2以马铃薯葡萄糖液体培养基发酵制备的无菌发酵液对7种供试菌株具有较强抑制作用,经形态、生理生化特征及16S r RNA基因序列分析,将其初步鉴定为解淀粉芽胞杆菌(Bacillus amyloliquefaciens)。菌株发酵液抑菌活性对温度、酸和紫外线具有较强的稳定性,对蛋白酶K、胃蛋白酶、碱性蛋白酶处理敏感。菌株发酵液存在抑菌蛋白和脂肽类物质。【结论】菌株PC2在食品保鲜和农业生防中具有潜在的开发应用价值。     

6种水蛭的COⅠ、12S rRNA和16S rRNA基因及分子进化分析

水蛭是一种常见的传统中药,为了解常见蛭类细胞色素氧化酶亚基Ⅰ（COⅠ）、12S rRNA和16S rRNA基因特征和水蛭分子系统进化关系。对常用的入药品种日本医蛭（Hirudo nipponia）、宽体金线蛭（Whitmania pigra）、尖细金线蛭（Whitmania acranulate）和相近物种菲牛蛭（Poecilobdella manillensis）、光润金线蛭（Whitmania laevis）及八目石蛭（Erpobdella octoculata）的COⅠ、12S rRNA和16S rRNA基因进行扩增、测序,利用Mega 5.0分析基因特征、颠换率、分化年代,利用PAUP＊4.10b和MrBayes 3.1.2构建分子系统树。结果表明6种水蛭的COⅠ、12S rRNA和16S rRNA基因全长分别为1534~1536 bp、709~744 bp、1129~1173 bp,GC含量分别为32.35%~34.79%、24.42%~28.49%、24.82%~27.02%,总体颠换率为0.002%~0.760%,分化年代为3.55×106a~9.85×106a;每种水蛭为单系群的支持值均≥82。说明COⅠ、12S rRNA和16S rRNA基因具有种间特异性,可用于6种水蛭的分类鉴别。