高通量细菌鉴定方法研究进展

高通量细菌鉴定是微生物领域的重要研究课题,对于疾病诊断和环境监测具有重要意义。相比传统的表型鉴定方法,分子遗传学鉴定方法具有稳定性高、检测周期短以及成本较低等特点,成为了主流的鉴定方法。特别是下一代DNA测序技术、核酸分子检测基础上的细菌检测芯片、质谱技术基础上的蛋白质图谱分析为高通量、快速、准确乃至定量的细菌鉴定提供了可行性方案。     

广西猕猴桃发展的策略分析

分析了广西猕猴桃发展的有利条件和现状, 并提出了相应的发展策略, 可供各级领导和有关生产单位参考, 对促进广西猕猴桃进一步发展具有指导意义。     

Germination and seedling growth of bog plants in relation to the recolonization of milled peatlands

Two controlled experiments were conducted to evaluate the potential for vascular plants to germinate and establish in milled peatlands and to assess whether easily measured plant traits can be used to predict their probable success. Study species included twenty species of perennial herbs, shrubs and trees occurring frequently in undisturbed bogs or abandoned milled bogs in Québec, Canada. First, a glasshouse experiment was performed to test the effect of burial under peat on germination and seedling emergence. Second, a growth chamber experiment was conducted to measure relative growth rate and other growth parameters of seedlings between 1 and 3 weeks of age. In the burial experiment, seedling emergence decreased exponentially with peat depth for most species examined. The slope of the exponential decline varied between species and was strongly correlated to seed mass. Seeds less than 0.1 mg in mass were most sensitive to burial. In the seedling growth experiments, Betula species had the highest absolute and relative growth rates, which may help to explain their prevalence in milled bogs. Relative growth rate (RGR) was not correlated with seed mass, however it was strongly correlated with leaf area ratio (LAR) and especially specific leaf area (SLA) of seedlings, except for species with seed mass less than 0.01 mg. Screening of species for seed mass and SLA should help predict their germination and establishment success or failure in milled peatlands and allow more directed interventions to favour the establishment of desirable species in milled bogs. This revised version was published online in August 2006 with corrections to the Cover Date.     

胶州湾放线菌的分离及其抗病原微生物的活性检测

采用涂布法,从胶州湾海泥样品中分离到224株放线菌菌株,并且从海水样品中分离到32株放线菌菌株。根据形态学特性,菌株被分成了7个组。同时利用杯碟法测定了它们的抗菌活性,其中约7％对金黄色葡萄球菌有活性,11％对八叠球菌有效,10％对大肠杆菌有效,11％对绿脓杆菌有效,2％对白色念珠菌有效,5％对隐球菌有效,6％对绿色产色链霉菌有效和6％对米赫毛霉有效。分离到的22％放线菌对所测定的病原微生物有抗性作用。我们的结果表明胶州湾放线菌能够产生对病原微生物有抗性作用的不同代谢物,这些代谢物可以作为筛选新颖天然产物的独特和丰富的资源。     

中国38个地区兰科植物区系成分的比较分析

通过对中国38个地区共147属,984种兰科植物的区系成分的统计,分析了各地区兰科植物的属种热带成分/温带成分(R/T)值随纬度的变化趋势;并利用SPSS 20.0软件对各地区兰科植物的区系成分进行聚类分析。结果表明:(1)38个地区147属兰科植物可划分为11种分布区类型和9种变型,984种兰科植物可划分为12种分布区类型和6种变型。(2)属级水平上R/T值随纬度的升高总体呈下降趋势,38个地区中23个地区为热带性质,13个地区为温带性质,峨眉山和金佛山的热带性质和温带性质相等;种级水平上除俄贤岭的特殊岛屿石灰岩环境造成极强的热带性质外,其他地区的R/T值随纬度的升高而降低,表现出明显的纬向地带性特点。(3)38个地区兰科植物属种级区系类型存在分异现象,即147属兰科植物以热带亚洲分布(24.71%)、北温带分布(19.14%)和热带亚洲至热带大洋洲分布(15.32%)为主,而984种兰科植物除热带亚洲分布(30.28%)外,则以中国特有分布(26.89%)和中国-日本分布(12.85%)为主。(4)属种级聚类结果显示,种级水平的聚类分析比属级水平的聚类更能体现出纬度相近其区系成分也相近的特点。     

Genetic Connectivity among Populations of an Endangered Snake Species from Southeastern Australia (Hoplocephalus bungaroides, Elapidae)

For endangered species that persist as apparently isolated populations within a previously more extensive range, the degree of genetic exchange between those populations is critical to conservation and management. A lack of gene flow can exacerbate impacts of threatening processes and delay or prevent colonization of sites after local extirpation. The broad-headed snake, Hoplocephalus bungaroides, is a small venomous species restricted to a handful of disjunct reserves near Sydney, Australia. Mark-recapture studies have indicated low vagility for this ambush predator, suggesting that gene flow also may be low. However, our analyses of 11 microsatellite loci from 163 snakes collected in Morton National Park, from six sites within a 10-km diameter, suggest relatively high rates of gene flow among sites. Most populations exchange genes with each other, with one large population serving as a source area and smaller populations apparently acting as sinks. About half of the juvenile snakes, for which we could reliably infer parentage, were collected from populations other than those in which we collected their putative parents. As expected from the snakes' reliance on rocky outcrops during cooler months of the year, most gene flow appears to be along sandstone plateaux rather than across the densely forested valleys that separate plateaux. The unexpectedly high rates of gene flow on a landscape scale are encouraging for future conservation of this endangered taxon. For example, wildlife managers could conserve broad-headed snakes by restoring habitats near extant source populations in areas predicted to be least affected by future climate change.     

Diversity and antimicrobial activity of endophytic fungi isolated from Nyctanthes arbor-tristis, a well-known medicinal plant of India

Endophytic fungi from Nyctanthes arbor-tristis were isolated and evaluated for their antimicrobial activity. A total of 19 endophytic fungi were isolated from 400 segments of healthy leaf and stem tissues of N. arbor-tristis. Eighteen endophytic fungi were obtained from leaf, while only ten from stem. Alternaria alternata had the highest colonization frequency (15.0%) in leaf, whereas Cladosporium cladosporioides ranked first in stem with a colonization frequency of 12%. The diversity and species richness were found higher in leaf tissues than in stem. The similarity indices between leaf and stem were 0.473 for Jaccard’s and 0.642 for the Sorenson index, respectively. Of 16, 12 (75%) endophytic fungal extracts showed antibacterial activity against either one or more pathogenic bacteria. The endophytic Nigrospora oryzae showed maximum inhibition against Shigella sp. and Pseudomonas aeruginosa. The leaf endophytes Colletotrichum dematium and Chaetomium globosum exhibited a broad range of anibacterial activity and were active against Shigella flexnii, Shigella boydii, Salmonella enteritidis, Salmonella paratyphi, and P. aeruginosa. Nine out of 16 (56.25%) endophytic fungi exhibited antifungal activity to one or more fungal pathogens. Colletotrichum dematium inhibited 55.87% of the radial growth of the phytopathogen Curvularia lunata. The antimicrobial activity of these endophytic microorganisms could be exploited in the biotechnological, medicinal, and agricultural industries.     

不同风化程度钾长石表面矿物分解细菌的筛选及遗传多样性

【目的】不同风化程度钾长石表面矿物分解细菌生物多样性研究将有助于了解矿物生物风化、生物成矿和土壤形成的演化规律和机理。【方法】采用纯培养法自南平钾矿区高、中、低风化度钾长石以及矿区土壤样品中分离矿物分解细菌,通过摇瓶释硅实验比较不同菌株分解矿物能力,采用16SrDNA限制性酶切多态性分析(Amplified rDNA Restriction Analysis,ARDRA)研究了供试菌株的遗传多样性。【结果】分离筛选到35株生长良好的矿物分解细菌,与对照相比,接菌处理发酵液中有效硅增加了101～206%;所有供试菌株可分为11个OTU,分别属于5个门,6个科,7个属。多数菌株(74%)属于γ-变形杆菌纲(γ-Proteobacteria)。泛菌属(Pantoea),沙雷氏菌属(Serratia),假单胞菌属(Pseudomonas)为优势种群。【结论】南平钾矿区矿物分解细菌具有丰富的微生物种群多样性,且γ-变形杆菌纲(γ-Proteobacteria)细菌在钾长石风化过程中可能起了重要的作用。     

小麦辐射二代性状的数量遗传分析

本文采用生物统计和数量遗传学方法、分析了辐照剂量为0（对照）、15、25、35KR的铯─137γ射线对二个小麦品种的诱变效应及其选择效果;估算了七个数量性状的分布特征数和遗传方差、遗传变异系数、遗传力、遗传进度、相对遗传进度等遗传参数。辐射二代的变异较大,有大粒、大穗、早熟突变体出现;株粒重、穗粒重、穗长、穗粒数、抽穗期的遗传变异系数和相对遗传进度都较大,选择效果较好;铯-137γ射线能有效地应用于小麦辐射育种,且适宜辐照剂量为35KR。     

海洋抑菌放线菌Y15的筛选、鉴定及其代谢产物理化性质

【目的】筛选产广谱、高效抑菌活性物质的海洋放线菌,为新型抗生素的开发奠定基础。【方法】采用琼脂块法初筛,打孔扩散法复筛,以金黄色葡萄球菌、大肠埃希氏菌、枯草芽孢杆菌和单核细胞增生李斯特菌为指示菌从海泥样品中筛选目标菌株;利用20种指示菌株考查Y10、Y11、Y15、Y16和Y21的抑菌谱;通过形态观察和16S r RNA基因序列分析确定菌株分类地位;以单核细胞增生李斯特菌的OD600值为指标探讨Y15抑菌活性物质对该菌的作用方式;以抑菌活性为指标研究Y15抑菌活性物质的理化性质。【结果】共分离12株具抑菌活性的海洋放线菌,其中Y15抑菌谱最广,对20种指示菌株中的18种具有抑菌活性,并且在4种培养基中均能产生抑菌活性物质。16S r RNA基因序列分析表明Y15属于小单孢菌属,并与Micromonospora endolithica亲缘关系最近。Y15抑菌活性物质在144 h达到最高值为480 AU/m L,在168-216 h保持平衡为320 AU/m L。Y15抑菌活性物质对单核细胞李斯特菌作用方式为杀菌。Y15抑菌活性物质在-20-60°C抑菌活性保持稳定,在80-120°C活性逐渐下降,但在120°C处理30 min仍保留37.5%的活性;在p H 7.0-10.0抑菌活性稳定,在p H 2.0-6.0和p H 11.0-12.0抑菌活性均有所损失;Y15抑菌活性物质对紫外和4种酶(蛋白酶K、胰蛋白酶、木瓜蛋白酶和α-淀粉酶)处理均保持稳定,表明活性物质为非蛋白和非多肽类的抑菌物质。【结论】Y15产生的活性物质具有良好的抑菌谱和抑菌活性,且较为稳定,具有较高的应用价值。