东太湖表层沉积物放线菌群落结构多样性及其空间异质性

采用基于16SrRNA基因变性梯度凝胶电泳(DGGE)方法,考察东太湖表层沉积物放线菌群落结构多样性及其空间分布特征.结果显示:东太湖表层沉积物中放线菌群落结构多样性较高,DGGE指纹图谱样品的平均条带数为21.5±2个,群落结构多样性(如Shannon-Wiener指数)在空间尺度上差异不明显;聚类分析表明放线菌群落结构空间分布特征表现为相邻采样位点群落结构较为相似,这可能与相邻位点沉积物理化性质类似有关.典型对应分析结果表明,东太湖表层沉积物中放线菌群落结构变化的主要影响因子为沉积物pH.     

青藏高原淡水湖普莫雍错和盐水湖阿翁错湖底沉积物中细菌群落的垂直分布

【目的】湖泊沉积物中存储着大量独特的微生物,这些微生物在湖泊生态系统生物地球化学循环中扮演着非常重要的角色。然而,很少有研究报道微生物群落在湖泊沉积物中的垂直分布。本文比较研究青藏高原淡水湖普莫雍错和盐水湖阿翁错沉积物在不同深度下细菌的丰度和群落结构。【方法】利用定量PCR(q PCR)和变性梯度凝胶电泳(DGGE)技术分别测定细菌群落的丰度与群落结构。【结果】定量PCR结果显示,湖泊沉积物中细菌丰度均随深度增加而降低,盐水湖阿翁错和淡水湖普莫雍错的细菌丰度分别从1011数量级降到108数量级,从1012数量级降到1010数量级。在相对应的沉积物层,淡水湖沉积物的细菌丰度比盐水湖高1-2个数量级。变性梯度凝胶电泳(DGGE)指纹图谱的分析表明,淡水湖沉积物细菌群落的DGGE条带数(丰富度)显著高于盐水湖(P=0.014);淡水与盐水湖泊沉积物细菌群落结构明显不同,同时在同一湖泊沉积物中上层(0-6 cm)和下层(7-20 cm)细菌群落结构也呈明显分异。系统发育分析表明,盐水湖阿翁错沉积物特有菌门为Gamma-变形菌、拟杆菌门、蓝细菌和栖热菌门,而淡水湖普莫雍错沉积物中特有菌门为Delta-和Beta-变形菌、酸杆菌和绿弯菌门。【结论】青藏高原淡水与盐水湖泊沉积物细菌丰度与群落结构具有明显的差异;同时,细菌群落结构在沉积物的不同深度也表现出差异。这些结果可为进一步阐明青藏高原湖泊生态系统中微生物对气候环境变化的响应提供科学依据。     

基于PCR-DGGE技术的红树林区微生物群落结构

【目的】为了解红树林沉积物中细菌的群落结构特征。【方法】应用PCR-DGGE技术对福建浮宫红树林的16个采样站位样品细菌的群落结构进行了研究。根据DGGE指纹图谱,对它们的遗传多样性进行了分析。【结果】各站位样品细菌多样性指数(H)、丰度(S)和均匀度(EH)均有所不同,这些差异与它们所处站位的不同有关,红树林区细菌多样性高于非红树林区细菌多样性。对不同站位细菌群落相似性分析,它们的相似性系数也存在一定的规律,同一断面的细菌群落结构相近性较高。对DGGE的优势条带序列分析,同源性最高的微生物分别属于变形菌门(Proteobacteria)、酸菌门(Acidobacteria)和绿菌门(Chlorobi),它们均为未培养微生物,分别来自于河口海岸沉积物。【结论】应用PCR-DGGE技术更能客观地反映红树林沉积物中真实的细菌群落结构信息。另外,研究也表明红树林区微生物多样性丰富,在红树林区研究开发未知微生物资源具有巨大的潜力。     

生物造粒流化床污水处理反应器的微生物多样性

为了研究生物造粒流化床污水处理反应器颗粒污泥的微生物种群多样性,分别从生物造粒流化床10、60和110cm处取颗粒污泥,通过细胞裂解直接提取颗粒污泥细菌基因组DNA,PCR扩增后经变性梯度凝胶电泳(DGGE)分离,获得微生物群落的DNA特征指纹图谱,对特征条带进行序列测定及序列同源性分析。16S rRNA序列分析表明,获得的18个OTUs均属于细菌域,其中61%属于变形菌,17%属于放线菌,11%属于低G C革兰氏阳性菌,11%属于其它未知细菌。     

舌苔细菌PCR-DGGE分析条件的建立与优化

目的针对口腔舌苔细菌16S rDNA序列进行变性梯度凝胶电泳(denaturing gradient gel electrophoresis,DGGE)适用序列的筛选及电泳条件的优化。方法以DGGE图谱的高分辨率为指标,选择舌苔细菌DGGE分离最适的16S rDNA高变区、电泳电压和电泳时间,并采用优化的条件分析健康青年人舌苔细菌群落的分布。结果舌苔细菌16S rDNA V3高变区引物序列能获得更加丰富清晰的DGGE条带;基于该区,当变性剂浓度为30%～60%、电泳温度60℃、电压60 V和电泳时间14 h时能得到分辨率最佳的DGGE图谱。运用此优化条件对12个样本舌苔细菌群落的分析表明,舌苔微生物主要由厚壁菌门、梭杆菌门、拟杆菌门和变形菌门等组成。优化后的DGGE技术对舌苔细菌多样性的分析具有准确性、灵敏性和可重复性。结论 DGGE图谱显示,不同分析条件对图谱类型和细菌多样性指数均有所差异。利用优化的DGGE条件能有效分离舌苔细菌16S rDNA V3区序列,为口腔微生物群落结构分析提供可靠的技术支持,也为其他不同生态细菌的多样性分析提供参考。     

DG-DGGE分析产氢发酵系统微生物群落动态及种群多样性

应用双梯度-变性梯度凝胶电泳(DG-DGGE)对生物制氢反应器微生物种群的动态变化及多样性进行监测。间隔7d从反应器取厌氧活性污泥,以细菌16SrDNA通用引物进行V2～V3区域PCR扩增,长约450bp的PCR产物经DGGE分离后,获得污泥微生物群落的16SrDNA指纹图谱。污泥接种到反应器后微生物群落中既有原始种群的消亡和增长,也有次级种群的强化和演变。反应器在运行初期群落演替迅速,15d时微生物群落结构变化最大。群落结构的相似性随着演替时间的增加而逐渐升高,种群动态变化后形成稳定的群落结构。29d时微生物多样性基本保持不变,微生物优势种属达到19个OTU。在细菌竞争和协同作用制约下,种群多样性降低后趋于稳定,形成顶级群落。有些种群在群落结构中一直存在,是群落建成的原始种群,原始种群与次级种群在代谢过程中具有协同作用,表现出群落的综合生态特征。     

新疆一号冰川土壤细菌多样性的研究

应用变性梯度凝胶电泳（DGGE）技术分离PCR扩增的16SrDNA来研究土壤微生物的多样性。直接从新疆一号冰川不同海拔高度的土壤样品中提取总DNA。用两套细菌通用引物分别扩增16SrDNA的V3和V6／V9高变区的特异性片段,PCR产物进行DGGE分析。PCR—DGGE图谱表明,PCR产物经DGGE检测到的条带清晰且分离效果好。结果表明,PCR—DGGE是一种快速研究微生物群落结构的有效方法。     

新疆一号冰川土壤细菌多样性的研究*

应用变性梯度凝胶电泳(DGGE)技术分离PCR扩增的16S rDNA来研究土壤微生物的多样性。直接从新疆一号冰川不同海拔高度的土壤样品中提取总DNA。用两套细菌通用引物分别扩增16S rDNA的V3和V6/V9高变区的特异性片段,PCR产物进行DGGE分析。PCR-DGGE图谱表明,PCR产物经DGGE检测到的条带清晰且分离效果好。结果表明,PCR-DGGE是一种快速研究微生物群落结构的有效方法。     

藏灵菇微生物种群结构的分子特性研究

用PCR—DGGE指纹技术,研究了藏灵菇中微生物多样性及藏灵菇发酵奶发酵过程微生物种群动力学。结果表明,藏灵菇中细菌的种群结构较酵母菌的复杂,不同来源的藏灵菇中细菌种群结构的相似性为78％-84％,酵母菌种群结构的相似性为80％-92％。发酵过程中细菌种群结构变化图谱中的条带B和条带E,以及酵母菌种群结构变化图谱中的条带N贯穿于整个发酵过程,是发酵过程的优势菌。序列分析表明,细菌种群结构的DGGE图谱中的绝大多数条带与乳酸菌相对应,其中最亮条带（条带E）的序列与乳酸乳球菌的相似性为100％。     

PCR指纹图谱技术分析人体口腔内微生物菌群结构

目的 应用PCR-DGGE指纹图谱技术对人体口腔微生物菌群结构进行系统性研究.方法 对1例健康人唾液周期性采集的样品和8例健康人个体的唾液与牙菌斑采集的样品,进行微生物群落总DNA的抽提.以此为模板扩增16S rRNA V3可变区,产物经DGGE指纹图谱分析其组成结构,并运用UVIBAND/MAP等软件比较所得群落指纹图谱的相似性指数.结果 同一健康人个体不同采样时间的唾液菌群结构相似性系数＞74%,通过对不同健康个体口腔样本的研究,发现同一个体的唾液与牙菌斑菌群结构存在差异（84%～95%）.结论 同一健康个体其唾液微生物菌群在一定时间内基本稳定,仅有微小的变化;唾液与同个体牙菌斑的微生物组成虽然存在差异,但这种差异要明显小于个体间的差异.     

On the origin of the Hirudinea and the demise of the Oligochaeta

The phylogenetic relationships of the Clitellata were investigated with a data set of published and new complete 18S rRNA gene sequences of 51 species representing 41 families. Sequences were aligned on the basis of a secondary structure model and analysed with maximum parsimony and maximum likelihood. In contrast to the latter method, parsimony did not recover the monophyly of Clitellata. However, a close scrutiny of the data suggested a spurious attraction between some polychaetes and clitellates. As a rule, molecular trees are closely aligned with morphology-based phylogenies. Acanthobdellida and Euhirudinea were reconciled in their traditional Hirudinea clade and were included in the Oligochaeta with the Branchiobdellida via the Lumbriculidae as a possible link between the two assemblages. While the 18S gene yielded a meaningful historical signal for determining relationships within clitellates, the exact position of Hirudinea and Branchiobdellida within oligochaetes remained unresolved. The lack of phylogenetic signal is interpreted as evidence for a rapid radiation of these taxa. The placement of Clitellata within the Polychaeta remained unresolved. The biological reality of polytomies within annelids is suggested and supports the hypothesis of an extremely ancient radiation of polychaetes and emergence of clitellates.     

On the ontogeny of the haptor and the evolution of the Monogenea

Data on the ontogeny of the posterior haptor of monogeneans were obtained from more than 150 publications and summarised. These data were plotted into diagrams showing evolutionary capacity levels based on the theory of a progressive evolution of marginal hooks, anchors and other attachment components of the posterior haptor in the Monogenea (Malmberg, 1986). 5 + 5 unhinged marginal hooks are assumed to be the most primitive monogenean haptoral condition. Thus the diagrams were founded on a 5 + 5 unhinged marginal hook evolutionary capacity level, and the evolutionary capacity levels of anchors and other haptoral attachement components were arranged according to haptoral ontogenetical sequences. In the final plotting diagram data on hosts, type of spermatozoa, oncomiracidial ciliation, sensilla pattern and protonephridial systems were also included. In this way a number of correlations were revealed. Thus, for example, the number of 5 + 5 marginal hooks correlates with the most primitive monogenean type of spermatozoon and with few sensillae, many ciliated cells and a simple protonephridial system in the oncomiracidium. On the basis of the reviewed data it is concluded that the ancient monogeneans with 5 + 5 unhinged marginal hooks were divided into two main lines, one retaining unhinged marginal hooks and the other evolving hinged marginal hooks. Both main lines have recent representatives at different marginal hook evolutionary capacity levels, i.e. monogeneans retaining a haptor with only marginal hooks. For the main line with hinged marginal hooks the name Articulon-choinea n. subclass is proposed. Members with 8 + 8 hinged marginal hooks only are here called Proanchorea n. superord. Monogeneans with unhinged marginal hooks only are here called Ananchorea n. superord. and three new families are erected for its recent members: Anonchohapteridae n. fam., Acolpentronidae n. fam. and Anacanthoridae n. fam. (with 7 + 7, 8 + 8 and 9 + 9 unhinged marginal hooks, respectively). Except for the families of Articulonchoinea (e.g. Acanthocotylidae, Gyrodactylidae, Tetraonchoididae) Bychowsky's (1957) division of the Monogenea into the Oligonchoinea and Polyonchoinea fits the proposed scheme, i.e. monogeneans with unhinged marginal hooks form one old group, the Oligonchoinea, which have 5 + 5 unhinged marginal hooks, and the other group form the Polyonchoinea, which (with the exception of the Hexabothriidae) has a greater number (7 + 7, 8 + 8 or 9 + 9) of unhinged marginal hooks. It is proposed that both these names, Oligonchoinea (sensu mihi) and Polyonchoinea (sensu mihi), will be retained on one side and Articulonchoinea placed on the other side, which reflects the early monogenean evolution. Except for the members of Ananchorea [Polyonchoinea], all members of the Oligonchoinea and Polyonchoinea have anchors, which imply that they are further evolved, i.e. have passed the 5 + 5 marginal hook evolutionary capacity level (Malmberg, 1986). There are two main types of anchors in the Monogenea: haptoral anchors, with anlages appearing in the haptor, and peduncular anchors, with anlages in the peduncle. There are two types of haptoral anchors: peripheral haptoral anchors, ontogenetically the oldest, and central haptoral anchors. Peduncular anchors, in turn, are ontogenetically younger than peripheral haptoral anchors. There may be two pairs of peduncular anchors: medial peduncular anchors, ontogentically the oldest, and lateral peduncular anchors. Only peduncular (not haptoral) anchors have anchor bars. Monogeneans with haptoral anchors are here called Mediohaptanchorea n. superord. and Laterohaptanchorea n. superord. or haptanchoreans. All oligonchoineans and the oldest polyonchoineans are haptanchoreans. Certain members of Calceostomatidae [Polyonchoinea] are the only monogeneans with both (peripheral) haptoral and peduncular anchors (one pair). These monogeneans are here called Mixanchorea n. superord. Polyonchoineans with peduncular anchors and unhinged marginal hooks are here called the Pedunculanchorea n. superord. The most primitive pedunculanchoreans have only one pair of peduncular anchors with an anchor bar, while the most advanced have both medial and lateral peduncular anchors; each pair having an anchor bar. Certain families of the Articulonchoinea, the Anchorea n. superord., also have peduncular anchors (parallel evolution): only one family, the Sundanonchidae n. fam., has both medial and lateral peduncular anchors, each anchor pair with an anchor bar. Evolutionary lines from different monogenean evolutionary capacity levels are discussed and a new system of classification for the Monogenea is proposed.In agreeing to publish this article, I recognise that its contents are controversial and contrary to generally accepted views on monogenean systematics and evolution. I have anticipated a reaction to the article by inviting senior workers in the field to comment upon it: their views will be reported in a future issue of this journal. EditorIn agreeing to publish this article, I recognise that its contents are controversial and contrary to generally accepted views on monogenean systematics and evolution. I have anticipated a reaction to the article by inviting senior workers in the field to comment upon it: their views will be reported in a future issue of this journal. Editor