水体粪便污染的微生物溯源方法研究进展

畜禽粪便和生活污水是造成水体污染的主要因素之一,明确和区分水体污染的来源对污染控制和治理尤为重要.因此,利用微生物进行水体污染的溯源近年来成为国际上的研究热点.本文对两种类型微生物溯源方法的研究现状、优缺点以及应用中存在的问题进行了综述和展望.认为在培养建库微生物溯源方法中重复序列分型应用性最强,而在非培养建库方法中基于大肠杆菌特异性基因的PCR-DGGE具有广阔的应用前景.非培养建库微生物溯源是今后主要的研究方向,培养建库和非培养建库溯源方法相结合才能使溯源结果更加可信.     

分子标记物在禽类粪便污染溯源中的研究及应用进展

排入环境后的禽类粪便不仅会造成水体和土壤环境污染,且其携带的致病菌对人类健康也存在潜在危害,因此快速准确地识别并控制粪便污染源对环境保护和人类健康至关重要。微生物溯源（Microbial source tracking,MST）技术可以利用分子标记物识别人和不同动物的粪便污染,从而有助于及时发现并控制粪便污染。鉴于禽类粪便对环境和人类健康的危害,越来越多的禽类MST标记物被开发并用于禽类的粪便污染溯源研究。归纳总结了多种禽类（如鸡、鸭、鸽子、海鸥、加拿大雁和沙丘鹤等） MST分子标记物及其敏感性和特异性,重点综述了禽类分子标记物的基因来源,包括细菌16S rRNA基因、线粒体DNA和功能基因等。其中,细菌16S rRNA基因在标记物设计中的应用最为广泛,源指示菌主要包括厚壁菌门（Firmicutes）、拟杆菌目（Bacteroidales）、放线菌门（Actinobacteria）、变形菌门（Proteobacteria）和梭杆菌门（Fusobacteria）及其家族成员;以cytb基因、ND5基因、16S rRNA基因和ND2基因等线粒体DNA （Mitochondrial DNA,mtDNA）为设计来源的禽类MST标记物在溯源研究中指示效果最好,具有很大的应用潜能;使用功能基因作为设计来源的禽类MST标记物种类较少,且均表现出较低的敏感性,但是将功能基因作为MST标记物的思路具有一定的参考价值。通过对多种禽类标记物指示效果的比较,能为科研人员快速选择禽类标记物时提供一定的参考。此外,还对禽类MST技术的现存问题进行了分析总结,并对其在我国的发展进行了展望,以期促进MST技术在我国环境质量监测领域中的发展和应用。     

脆弱拟杆菌的研究进展

脆弱拟杆菌是定殖于哺乳动物肠道中的共生菌,同时也是临床感染病例中常见的条件致病菌。本文从致病及益生特性两大方面综述脆弱拟杆菌的研究现状,着重讨论了脆弱拟杆菌作为潜在益生菌在预防和治疗糖尿病及免疫性疾病中所起的重要作用,从而为筛选及应用益生脆弱拟杆菌菌株提供一定的参考。     

拟杆菌微生态制剂对仔猪免疫能力的影响

目的 探究拟杆菌微生态制剂对仔猪免疫力的影响.方法 选取断奶仔猪30头,随机分为3组.对照组直接饲喂基础日粮,第1组饲喂拟杆菌微生态制剂,第2组饲喂复合拟杆菌微生态制剂.在实验前对所有实验猪与对照仔猪全部进行猪瘟及蓝耳病免疫,随后进行4周实验,测定各个个体抗体水平.结果 饲喂拟杆菌 微生态制剂实验组的抗体水平比空白对照组提高了15％,而复合拟杆菌微生态制剂的抗体水平比空白对照组提高了91％,且明显提高了猪瘟抗体效价.结论 给仔猪饲喂拟杆菌微生态制剂可以提高仔猪产生免疫抗体的能力,从而增强仔猪抗猪瘟与蓝耳病的能力.     

拟杆菌的研究及应用

拟杆菌大量存在于宿主体内,对宿主的健康起着重要的作用。当宿主微生态平衡被破坏时它又是条件致病菌,使宿主患病。主要总结了最近10年来国内外学者对拟杆菌的研究状况,重点对拟杆菌的致病及益生机理进行了阐述。此外,还介绍了几株有重要应用价值的拟杆菌,并就以后的研究趋势作了展望。     

枯草芽孢杆菌无标记遗传操作技术研究进展

枯草芽孢杆菌是革兰氏阳性菌的模式生物,长期以来在代谢工程和工业微生物领域扮演重要角色。枯草芽孢杆菌无标记遗传操作技术对后基因组时代的基因功能研究和菌株生理特性的改造起着关键作用。综述枯草芽孢杆菌无标记遗传操作所使用的负筛选标记基因,总结目前主流的无标记遗传操作的策略,并提出枯草芽孢杆菌无标记遗传操作技术面临的主要问题和发展方向。     

牙髓拟杆菌的分离,培养,鉴定

牙髓拟杆菌是产黑色素拟杆菌群中的一个新菌种。本试验通过对牙髓腔感染标本中分离、培养、鉴定各种细菌,发现牙髓拟杆菌主要分布在牙髓腔内,其存在与根尖周炎有无症状密切相关,此菌对氧敏感,用常规鉴定及气相色谱法与其它菌无法区别,而间接免疫荧光法是确定牙髓拟杆菌菌种和直接检测牙髓腔标本中有无此菌的一个快速、可靠的方法。     

动物粪便中分子遗传信息的应用

动物粪便是非损伤性取样方式应用最广泛的样本,其中含有大量食物、微生物和宿主的遗传物质。本文重点介绍了结合分子生物学技术和高通量测序技术提取粪便样本的遗传信息,用于探索动物食性、肠道微生物种类及组成,检查寄生虫感染情况,筛选粪便标记物,评估种群遗传结构等应用,不仅突破了传统粪便应用研究的限制,还扩大了应用范围。通过简述粪便样本中所提取遗传信息的相关研究进展,为粪便样本在环境、野生动物和放牧动物中的应用提供参考。     

微生物对拟除虫菊酯类农药残留的生物修复

拟除虫菊酯类农药是一类高效、广谱农药,且具有低毒性和能被生物降解之特性,但其残留却给人们的健康带来了巨大的威胁,如何有效地去除其残留成为摆在环境工作者面前的一项重大课题。以生物修复为理论基础的农药残留降解菌技术为解决这一难题带来了新思路,该方法操作简便、经济实用,在国内外均成为环境工作者的研究热点。     

拟寄生蜂的寄主标记研究进展

拟寄生蜂常借助寄主标记信息素 (host marking pheromone, HMP) 来辨别已寄生寄主和健康寄主,避免过寄生和多寄生,减少后代的种内和种间竞争。寄主标记有外部标记、内部标记和“容器”及区域标记3种方式。HMP来源于拟寄生蜂的杜氏腺、毒腺、输卵管、卵巢、卵或咽侧体,由触角或产卵器感受。目前已鉴定出几种拟寄生蜂的HMP,多数为饱和与不饱和烃类的混合物,但卡氏盾痣细蜂Dendrocerus carpenteri的HMP是保幼激素。拟寄生蜂对寄主标记的反应受HMP持效期,拟寄生蜂内部状况如载卵量、年龄、经验和学习,及外部条件如拟寄生蜂和健康寄主种群密度以及寄主种类的影响。本文还讨论了HMP研究的理论和实际意义。     

Effect of oxygen and temperature on the dynamic of the dominant bacterial populations of pig manure and on the persistence of pig-associated genetic markers, assessed in river water microcosms

Aims: The aim is to evaluate the dynamic of Bacteroides–Prevotella and Bacillus–Streptococcus–Lactobacillus populations originating from pig manure and the persistence of pig‐associated markers belonging to these groups according to temperature and oxygen. Methods and Results:  River water was inoculated with pig manure and incubated under microaerophilic and aerobic conditions, at 4 and 20°C over 43 days. The diversity of bacterial populations was analysed by capillary electrophoresis‐single‐strand conformation polymorphism. The persistence of the pig‐associated markers was measured by real‐time PCR and compared with the survival of Escherichia coli and enterococci. Decay was characterized by the estimation of the time needed to produce a 1‐log reduction (T90). The greatest changes were observed at 20°C under aerobic conditions, leading to a reduction in the diversity of the bacterial populations and in the concentrations of the Pig‐1‐Bac, Pig‐2‐Bac and Lactobacillus amylovorus markers with a T90 of 10·5, 8·1 and 17·2 days, respectively. Conclusions: Oxygen and temperature were found to have a combined effect on the persistence of the pig‐associated markers in river waters. Significance and Impact of the Study: The persistence profiles of the Pig‐1‐Bac, Pig‐2‐Bac and Lact. amylovorus markers in addition to their high specificity and sensitivity support their use as relevant markers to identify pig faecal contamination in river waters.     

Lack of specificity for PCR assays targeting human Bacteroides 16S rRNA gene: cross-amplification with fish feces

Methods focused on members of the genus Bacteroides have been increasingly utilized in microbial source-tracking studies for identifying and quantifying sources of nonpoint fecal contamination. We present results using standard and real-time PCR to show cross-amplification of Bacteroides 16S rRNA gene molecular assays targeting human fecal pollution with fecal DNA from freshwater fish species. All except one of the presumptively human-specific assays amplified fecal DNA from at least one fish species, and one real-time PCR assay amplified DNA from all fish species tested. Sequencing of PCR amplicons generated from fish fecal DNA using primers from the real-time assay revealed no mismatches to the human-specific probe sequences, but the nucleotide sequences of clones from fish fecal samples differed markedly from those of human feces, suggesting that the fish-related bacteria may be different strains. Our results strongly demonstrate the potential for cross-amplification of human-specific PCR assays with fish feces, and may call into question the results of studies in which these Bacteroides- specific molecular markers are used to quantify human fecal contamination in waters where fish contribute to fecal inputs.     

乳及乳制品中病原微生物溯源技术研究进展

牛奶营养丰富,素有\"白色血液\"之称,随着公众对食源性疾病原因和来源问责制的需求增加,准确追踪特定食源性病原微生物在暴发过程中所经过的途径变得越来越重要.微生物溯源研究有助于人们更深入地了解病原微生物种群结构及其多样性的起源和进化,为病原微生物的检验、流行监测、综合防治等研究提供重要的信息资料和科学依据.在牛奶中病原微生...     

The persistence of bifidobacteria populations in a river measured by molecular and culture techniques

Aims:  To determine relative to faecal coliforms (FC) and sulfite-reducing clostridia (SRC), the environmental persistence of natural populations of Bifidobacterium spp. enumerated by culturing and quantitative polymerase chain reaction (q-PCR).
Methods and Results:  Dialysis tubing containing river supplemented with overnight cultures of Bifidobacterium adolescentis (BA) and Bifidobacterium dentium (BD) or urban wastewater were suspended in a river for up to 10 days. At intervals, the contents of each dialysis tube were assayed using q-PCR assays for BA and BD, and selective culture media for FC, SRC, total bifidobacteria (TB), sorbitol-fermenting bifidobacteria (SFB) and cultivable BA. Mean summer T ₉₀ values were 251 h for SRC, 92 h for FC, 48 h for BA and BD by q-PCR, and 9 h for TB.
Conclusions:  Bifidobacterium spp. was the population with the lowest persistence, showing seasonal differences in T ₉₀ when measured by culture techniques or by q-PCR. This difference in relative persistence is because of a longer persistence of molecular targets than cultivable cells.
Significance and Impact of the Study:  The persistence of a viable bifidobacteria cells is shorter, but the longest persistence of molecular targets. This factor could be used for origin the faecal pollution in water for the development of microbial source tracking (MST).