分离自甘肃天祝五台岭土壤的放线菌拮抗性的初步研究

从甘肃天祝县土壤中分离到的27株放线菌,作为测试放线菌拮抗性的供试茵株.抗菌试验表明,14株放线菌对6株革兰氏阳性菌和阴性菌以及白色念殊菌等指示菌有抗性.菌株WTL-4、WTL-20和WTL-26抗菌谱最广,WTL-4能抗3种革兰氏阳性菌,WTL-20能抗革兰氏阳性的金黄色葡萄球菌和单增李斯特菌、革兰氏阴性的沙门氏菌及真菌白色念殊菌,WTL-26能抗革兰氏阳性的金黄色葡萄球菌和单增李斯特菌及革兰氏阴性的沙门氏菌.抗肿瘤试验表明,有8株菌株对肿瘤细胞有抑制作用,其中抑制率在60%以上的菌株占18.5%.对抗肿瘤活性较高的3株菌WTL-4、WTL-14和WTL-15以及没有抗菌和抗肿瘤活性的菌株WTL-27进行了系统发育分析.从系统发育树可以看出,4株菌均属于链霉菌属(Streptomyces).菌株WTL-4与Streptomyces viridochromoqenes的相似性为98%;菌株WTL-14和WTL-15的相似性达到99.2%,它们与S.flavolimosus 174457的相似性达到99.4%;WTL-27与S.mycroflavus的相似性为99%.     

26株具有细胞毒活性的海洋放线菌的系统发育研究

从海南红树林的海泥和海藻样品中分离得到26株具有细胞毒活性的放线菌(Actinomycetes),根据其形态学特征、生理生化特性及16SrDNA序列分析结果,确定菌株0617230属于小单孢菌属(Micromonospora),与Micromonosporaechinospora的相似性为97%。其余25株菌株属于链霉菌属(Streptomyces),其中菌株050643与其亲缘关系最近的Streptomycesviolaceolatus的相似性仅为96%;菌株061342与其亲缘关系最近的Streptomyceskasug-aensis、Streptomyceskasugaensis、Streptomycesmorookaensis的相似性仅为95%;菌株061303等11株菌株与其亲缘关系最近的Streptomyceskasugaensis、Streptomyceskasugaensis、Streptomycesmorookaensis的相似性仅为95%;因此它们可能是新种。     

高望界土壤放线菌抗菌活性筛选及生物学特征

为了从土壤环境中筛选产生抗菌活性物质的放线菌,采用琼脂扩散法对分离自湖南省高望界自然保护区森林土壤的169株放线菌进行抗菌活性检测,采用16S RNA基因序列分析法进行系统发育分析,采用常规方法进行生物学特性研究。结果表明,有47株受试菌株的发酵产物显示抗菌活性阳性(27.8%),其中6株具有较强抗菌活性。形态观察结果表明,这6株菌株均为典型的产丝产孢放线菌,在多数培养基上生长良好,气生菌丝和孢子丝丰富。系统发育分析表明,6株菌株均属于链霉菌属(Streptomyces),归为5个物种。菌株JSM 147612、JSM 147786、JSM 147831和JSM 147846分别与链霉菌属的已知物种S.violascens(序列相似性为99.93%)、S.malachitospinus(99.65%)、S.anulatus(99.72%)和S.aureus(99.38%)系统发育关系最为密切;菌株JSM 147823和JSM 147842之间的序列相似性为99.86%,应该属于同一物种,与它们系统发育关系最为密切的是S.albidoflavus(相似性分别为99.72%和99.58%)。     

泥河湾大长梁遗址和马圈沟Ⅰ文化层放线菌的分离及系统发育分析

为分析泥河湾盆地大长梁遗址和马圈沟Ⅰ文化层中可培养放线菌的物种多样性,本实验通过平板稀释涂布法对该区域土样进行放线菌的物种分离,得到197株放线菌纯培养物。采用链霉菌属特异引物对放线菌纯培养物进行初步鉴定,确定143株放线菌归属于链霉菌属。对未被鉴定的54株放线菌进行16S rDNA全序列测定并分析其系统发育关系。最终,将197株放线菌归属于放线菌纲下的5个亚目,6个科,10个属。其中,马圈沟Ⅰ文化层的分离菌株12-9与Nocardioides albus KCTC 9186T之间的16S rDNA序列相似性是93.73%,可能是一个潜在新属;大长梁遗址的分离菌株18-64与Haloglycomyces albus YIM 92370T的16S rDNA序列相似性是93.64%,可能是一个潜在新属。     

一株产天然蓝色素海洋链霉菌的筛选鉴定

从胶州湾附近海域水样中分离筛选到一株可产生天然蓝色素的链霉菌。采用通用引物16F27/16R1492扩增该菌株的16SrDNA,对测序结果进行序列分析,采用Neighbor-Joining(N-J)法构建系统发育进化树,同时结合链霉菌的传统形态学和生理生化特性对菌株进行鉴定。16SrDNA序列分析表明菌株与Streptomyces violaceolatus KCTC 9772相近,相似率为99%。在Neighbour-Joining法构建的系统发育进化树中,该菌株与Streptomyces violaceolatus聚类在同一分枝上。因此将该菌株鉴定为紫边链霉菌Streptomyces violaceolatus。     

对叶榕榕果内生细菌分离鉴定及抑菌活性的研究

【目的】为植物-内生细菌的生态关系研究, 以及植物内生细菌资源的利用提供一定的依据。【方法】采用微生物学传统分离培养的方法从对叶榕果实中分离到内生细菌54株, 通过限制性酶切分析(ARDRA)共有16个操作分类单元(Operational taxonomic units, OTUs), 对16株代表菌株16S rDNA序列系统发育分析。【结果】16个菌株都找到了与其相似性最高的菌株, 相似性达到95%?100%。其中6株为芽孢杆菌Bacillus属, 为对叶榕果实内生细菌优势菌属; 3株为Staphylococcus属, 2株为Pseudomonas属, 1株为Serrata属, 1株为非培养细菌的同源菌, 1株为Kocuria属, 1株为Delftia属, 还有1株为Acinetobacter属。【结论】这16株内生菌在系统发育树中明显聚为两大支; 在参与抑菌试验的14株内生菌中, 有13株对受试菌有不同程度的拮抗作用。尤其是其中的芽孢菌属的Swx15和不动杆菌属的Swx25菌株, 抑菌作用较强, 且有较广的抑菌谱性。     

甘肃酒泉等地区豆科植物根瘤菌的遗传多样性和系统发育分析

采用16S rDNA PCR-RFLP和16S rDNA全序列分析技术对采集自甘肃酒泉、嘉峪关等8个地区的豌豆、菜豆等几个不同豆科植物根瘤中分离的53株供试菌株和9株参比菌株进行了遗传和系统发育分析。16S rDNA PCR-RFLP结果表明,在77.5%的相似性水平上全部供试菌株聚成5个分支。分支I为Sinorhizhobium-Rhizobium分支,分支II为Agrorhizobium-Bradyrhizobium分支,分支III是未知供试菌组成的分支,分支IV为Mesorhizobium分支,分支V为2株未知供试菌组成的分支。在89.8%的相似性水平上,分支I包括2个亚分支:亚分支1由CNU1008等14株供试菌组成,与Sinorhizobium meliloti LISPA1002T菌株聚在一起;亚分支2包括6株未知菌,与Rhizobium leguminosarum USDA 2370T聚在一起。分支II包括3个亚分支:亚分支1包括CNU 1041等4株菌,与2株Agrobacterium tumefaciens IAM 13129T和IAM 13569T聚在一起;亚分支2包括5株菌,与Bradyrhizobium japonicum USDA 6T菌株聚在一起;亚分支3包括3株未知菌。选取各分支和亚分支的代表菌株进行16S rDNA测序,结果表明,两种分析方法在结果上具有较好的一致性。处于分支I的Sinorhizobium亚分支的菌株,与S.fredii和S.meliloti的相似性达到99%,该亚分支菌株的确切系统发育地位有待于DNA-DNA杂交来确定。处于分支I的Rhizobium亚分支的菌株,与R.giardinii的相似性达到99%,与R.etli的相似性为98%。同样,该亚分支的确切地位有待于DNA-DNA杂交来确定。处于分支II Agrobaterium亚分支的菌株与A.rubi的相似性达到99%。处于分支II Bradyrhizobium亚分支的菌株,与B.liaoningense的相似性达到99%。     

烟草可培养内生细菌的分离及多样性分析

采用稀释平板法, 从健康烟草的根、茎、叶组织中分离到267株内生细菌。利用细菌菌落表征性状和16S rRNA序列对这些分离物进行了多样性分析。通过数值分析比较了8个菌落形态表征性状, 以类平均连锁聚类法的方式进行聚类分析, 在2.15的水平上可分成5个聚类群和56个亚群。16S rDNA序列系统发育分析表明267株分离物可分为21个类群。研究表明同一菌落形态类型的菌株在系统发育树中不一定聚为一类, 菌落形态分类与分子生物学方法分类结果不完全一致。经克隆测序分析表明, 这267株分离物分别与GenBank中6类细菌中的21个已知种相似性达到98%?99%。其中芽孢杆菌属(Bacillus)细菌是烟草可培养内生细菌的优势种群。     

一株白芍内生放线菌的分离、活性及系统发育分析

目的:分离白芍中拮抗农作物致病菌和人类常见病原菌的内生放线菌,并进行系统发育分析。方法:采用3种分离培养基,从白芍根部分离内生放线菌;通过滤纸片法筛选具有拮抗活性的菌株,观察菌丝形态,并进行16S rDNA序列系统发育分析。结果:从白芍中分离得到16株内生放线菌,其中从FYSCA培养基中分离到9株;16株内生放线菌中有6株具有拮抗作用,菌株S-BS033004对5种病原菌有拮抗活性,尤其是对棉花黄萎病菌和小孢拟盘多毛孢菌和耐青霉素类金黄色葡萄球菌的拮抗作用显著,抑菌圈≥20mm。经16S rDNA系统发育分析表明该菌株与Streptomyces anulatus NBRC13369T等6株链霉菌模式菌株亲缘关系较近,相似性均为99.7%。结论:白芍内生放线菌S-BS033004是一株杀菌谱较广的链霉菌,具有很好的开发潜力。     

河西走廊酒泉地区盐碱土壤中可培养放线菌多样性

为了探究甘肃河西走廊酒泉地区盐碱土壤中可培养放线菌种群多样性信息,采用稀释平板涂布法对采集到的4个盐碱土样进行分离培养纯化,并基于16S rRNA基因序列对分离的放线菌株进行系统发育分析。结果显示:根据菌落的表型差异从中共分离到63株放线菌菌株,它们分属于7个亚目、11个科、24个属;其中Streptomyces属为河西走廊酒泉地区盐碱土壤中可培养放线菌的优势菌群,共分离到24株,占放线菌种群总数的38.1%,并且有22株放线菌与已知菌序列的相似性低于98%,占放线菌总数量的34.9%。表明,河西走廊酒泉地区盐碱土壤中的放线菌资源丰富,类群具有多样性。     

Mycotoxin production from fungi isolated from grapes

AIMS: In order to assess the potential for producing mycotoxins, fungi were isolated from wine producing grapes. METHODS AND RESULTS: The isolates were identified and Penicillium expansum, the most well recognized mycotoxin producer, was analysed for mycotoxin production by TLC. Many of the strains produced patulin and/or citrinin, often depending on whether they were grown on a grape or yeast extract sucrose media. CONCLUSION: Citrinin was produced by all strains grown in the yeast extract sucrose medium, but only one strain (from 51) was able to produce this compound in grape juice medium. Patulin was produced in the yeast extract medium by 20 strains and in grape juice medium by 33 strains. SIGNIFICANCE AND IMPACT OF THE STUDY: The presence of mycotoxins in wine producing grapes is discussed. Grapes contamination with patulin seems not to contribute to wine contamination, and no ochratoxin producing fungi was identified.     

Diterpenes derived from clerodanes from Pulicaria angustifolia

The investigation of Pulicaria angustifolia afforded, in addition to known triterpenes and caryophyllene epoxide, four methyl esters of diterpenes, all derived from clerodane. Three of them are derivatives of seco-nidoresedic acid. The structures were elucidated by spectroscopic methods.     

Genotyping Echinococcus granulosus from dogs from Western Iran

Cystic echinococcosis is a zoonotic infection caused by the dog tapeworm, Echinococcus granulosus. In the present study, adults of E. granulosus (n = 20) were collected from 71 dogs from Western Iran and were genetically characterized using DNA sequencing of the partial mitochondrial cytochrome c oxidase subunit 1 (cox1) and NADH dehydrogenase 1 (nad1). Consensus sequences were obtained for cox1 (366) and nad1 (471) genes. Phylogenetic analysis of concatenated nad1 and cox1 nucleotide sequence data was performed using Bayesian Inference approach. Overall, the dog isolates indicated nine different sequences in cox1 and seven in nad1 genes. Three genotypes (G1 [75%], G2 [10%] and G3 [15%]) were identified from the isolates. The G2 sequences indicated 100% homology with reference G2 sequence in both cox1 (Genbank accession number M84662) and nad1 (AJ237633) genes. G3 sequences showed 100% homology with G3 reference sequence in nad1 (AJ237633), but displayed two different cox1 profiles, each having 99% homology with reference G3 sequence (M84663). In the phylogenetic tree all of the isolates were grouped into a distinct cluster corresponding to the G1–G3 complex with relevant reference sequences. The presence of G1 genotype (sheep strain) of E. granulosus sensu stricto as dominant genotype in dogs is emphasized. To the best of our knowledge, this study established the first record of E. granulosus sensu stricto, G2 genotype in Iran.