潮间带盐生植物生境微生物药用前景

近海潮间带植物生境的微生物是最富有生物多样性的海洋种群,其生境的独特性决定了该区域微生物较高的药用价值。文中介绍了我国南北方海域近海潮间带植物生境和微生物的特性及药用前景,为该区域微生物的开发利用提供参考。     

特殊生境微生物及其活性代谢产物研究进展

微生物是一种重要的生物资源,特别是近来年,从特殊生境微生物中寻找具有重要生物活性代谢产物成为一个热点研究领域。主要就特殊生境微生物代谢产物的特殊性、特殊生境适应机制及其活性代谢产物等方面的研究进展和前景进行了简要的阐述,为特殊生境微生物的研究与开发提供参考。     

毛乌素沙地根际土壤微生物数量与植物盖度相关性的初步研究

对毛乌素沙地不同生境下根际土壤微生物细菌、真菌、放线菌的数量进行了研究,结果表明：根际不同菌种菌落总量表现为细菌最多,放线菌次之,真菌最少;地貌部位、植物类型等不同生境条件下,微生物菌落总量和垂直分布上均存在明显差异;固定沙丘迎风坡及荒草地的生物多样性指数高于其他地方,各微生物类群间分布比例较均匀。植物盖度与微生物的数量并不存在直接的相关性。因此,在改善毛乌素沙地生态环境时,应关注不同生境条件下植被演替的递续性和植物类型的配置。     

广州南沙十四涌潮间带三种生境的大型底栖动物群落比较

为了解广州南沙十四涌潮间带大型底栖动物的群落结构,于2007和2008年在十四涌潮间带选择光滩、海桑(Sonneratia)和茳芏(Cyperus malaccensis)3种生境进行大型底栖动物调查。对4个季度定量取样获得的大型底栖动物群落结构和差异进行比较分析,结果表明:从种数、平均生物量和丰度指数上看,茳芏生境最多,光滩第二,海桑生境最少;从大型底栖动物平均密度、种类多样性指数和均匀性指数上看,光滩最高,茳芏第二,海桑生境最低。ANOVA分析表明,3种生境间大型底栖动物的物种数、密度均呈显著差异,但生物量无显著差异。非度量多维标序(MDS)和聚类分析表明,冬季光滩和茳芏生境的大型底栖动物群落比较相似;3种生境的春季和夏季大型底栖动物群落比较相似。同时对3种生境间群落组成和数量差异的原因进行了探讨。     

特殊生境微生物及其活性代谢产物研究进展*

微生物是一种重要的生物资源,特别是近来年,从特殊生境微生物中寻找具有重要生物活性代谢产物成为一个热点研究领域。主要就特殊生境微生物代谢产物的特殊性、特殊生境适应机制及其活性代谢产物等方面的研究进展和前景进行了简要的阐述,为特殊生境微生物的研究与开发提供参考。     

模拟增温及分解界面对茭草凋落物分解速率及叶际微生物结构和功能的影响

挺水植物的凋落物是湿地生态系统物质循环的重要组成部分, 阐明气候变暖以及生境差异对湿地挺水植物凋落物分解过程及叶际微生物的影响对揭示湿地生态系统关键物质循环过程具有重要意义。该研究以滇西北高原典型湿地优势挺水植物茭草(Zizania latifolia)为研究对象, 采用凋落物袋法研究了茭草在模拟增温(1.5-2.0 ℃)及不同生境(大气界面、水界面与土界面)下的质量残留率和叶际微生物数量、结构组成与功能代谢特征。研究发现: 模拟气候变暖及生境差异均显著影响凋落物的分解速率。经过一年的分解, 凋落物在模拟增温环境下的质量残留率为66.4%, 对照组的质量残留率为77.7%, 增温组分解常数(k)值是对照组的1.64倍, 而凋落物在水界面与土界面的质量残留率为42.2%和25.3%, 其k值分别为大气界面的3.63和5.25倍, 生境差异是影响湿地挺水植物凋落物分解速率的关键因素。模拟增温主要改变了凋落物叶际微生物的群落组成特征, 而生境变化主要影响叶际微生物的绝对数量、微生物多样性、群落结构组成以及功能代谢活性。处于土界面的凋落物叶际微生物具有最高的群落功能代谢活性及醇类碳源利用程度。不同处理之间的植物叶际微生物特征与凋落物分解速率具有较好的一致性, 为揭示湿地植物凋落物分解快慢的微生物驱动机制提供了重要的理论依据。     

锡林河流域植物化学成分与植物类群及其生境关系的定量分析

植物化学成分与植物类群和所处生境关系密切。应用系统聚类分析、因子分析（采用主因子法和因子斜交旋转）等多元统计方法对锡林河流域１２２种植物的化学成分与植物类群和所处生境的关系进行了定量分析。分析结果说明上述方法可以较为准确地揭示数据中的如下规律：锡林河流域草原植物化学成分一方面与植物类群有关,受自身历史演化的决定,另一方面更受到所处生境条件的极大影响和制约。其中,禾本科、豆科植物分别具有其明显的化学成分特征;撂荒地群落与自然群落中植物、沙质与非沙质生境中植物化学成分差异较显著。因子分析中认为存在大量元素与微量元素两个公共因子,分别代表着植物中大量元素与微量元素的含量状况。豆科与禾本科相比,豆科植物因其具固氮能力,所含大量元素水平较高,而禾本科植物因细胞壁硅质化,含微量元素稍高;沙质生境因其养分贫瘠,植物的大量与微量元素均较非沙质生境中的低;特别是本区地带性土壤－栗钙土与特异性生境沙带中的疏林沙土相比,疏林沙土上植物大量与微量元素含量较栗钙土区植物明显偏低。     

不同积水生境对河南黄河湿地植物多样性的影响

湿地作为水陆交替的过渡地带,承担着重要的生态服务功能,湿地植物是生态功能作用发挥的基础。不同积水生境与湿地植物物种组成和分布关系密切。黄河流域是国家的重要生态屏障,湿地面积广阔,河南黄河湿地作为黄河湿地的重要组成部分,其积水生境对植物多样性的影响尚不清晰。为研究河南黄河湿地植物的多样性现状以及积水生境对其植物多样性的影响,采用样方和样线相结合的方法对河南省7个黄河湿地自然保护区中的湿地植物进行调查,共设置样方981个。重点分析了不同积水生境湿地植物的主要群系和物种组成,研究了各生境物种多样性和群落多样性特征（α多样性）,对比了的不同积水生境植物物种组成相似性和群落间相似程度（β多样性）,明确了各生境的植物物种排序和指示种。结果表明：（1）河南黄河湿地植物群系以草本群系为主,共发现188种湿地植物,分属56科,138属;（2）不同积水状况湿地植物物种丰富度大小依次为：季节性积水 > 永久性积水 > 间歇性积水 > 季节性水涝,主要群系总数与物种丰富度趋势表现一致;（3）不同积水生境湿地植物的物种组成存在显著差异,季节性积水和永久性积水生境中植物物种组成相似性和群落间相似程度最高,各积水生境均有明显的优势种和指示种。河南黄河湿地积水生境在不同流段差异显著,不同积水生境下植物多样性和主要植物群系有明显区别,进行湿地生态建设时,建议优先保护季节性积水生境,减少季节性水涝生境的产生,以达到维持物种多样性,发挥湿地最大生态价值的目的。     

生境片断化对植物种群遗传结构的影响及植物遗传多样性保护

生境片断化是指大而连续的生境变成空间隔离的小种群的现象。生境片断化对植物种群遗传效应包括生境片断化过程中的取样效应及其后的小种群效应（遗传漂变、近交等）。理论研究表明,生境片断化后,植物种群的遗传变异程度将降低,而残留的小种群间的遗传分化程度将升高。然而对一些植物的研究表明,生境片断化对植物种群的遗传效应要受其他一些因素的影响,如世代长度、片断化时间、片断种群的大小、基因流的改变等。最后,针对生境     

南海Formosa冷泉区沉积物微生物多样性与分布规律研究

【目的】当前对全球冷泉生态系统微生物生态学研究显示，冷泉生态系统中主要微生物类群为参与甲烷代谢的微生物，它们的分布差异与所处冷泉区生物地球化学环境密切相关。但在冷泉区内也存在环境因子截然不同的生境，尚缺乏比较冷泉区内小尺度生境间微生物多样性和分布规律的研究。本研究旨在分析南海Formosa冷泉区内不同生境间微生物多样性差异，完善和理解不同环境因子对冷泉内微生物群落结构的影响。【方法】对采集自南海Formosa冷泉区不同生境(黑色菌席区、白色菌席区和碳酸盐岩区)沉积物样本中古菌和细菌16S rRNA基因进行测序，结合环境因子，比较微生物多样性差异，分析环境因子对微生物分布的影响。【结果】发现在Formosa冷泉内的不同生境中，甲烷厌氧氧化古菌(anaerobic methanotrophic archaea,ANME)是主要古菌类群，占古菌总体相对丰度超过70%；在菌席区ANME-1b和ANME-2a/b是主要ANME亚群，碳酸盐岩区则是ANME-1b。硫酸盐还原菌(sulfate-reducing bacteria,SRB)和硫氧化菌(sulfur-oxidizing bacteria...     

Winter Planktonic Microbial Communities in Highland Aquatic Habitats

Winter conditions in aquatic habitats of the temperate zone markedly differ from those present in warmer seasons, nevertheless, relatively scarce information is available on planktonic microbial composition, as sites are not easily accessible and it was supposed traditionally that microbial activity is low during this cold period. Since microorganisms could have great impact on the ecosystem even during winter, we explored various sites in the Eastern Carpathians regarding the abundance and taxonomic composition of planktonic microorganisms. Although many of the studied environments were extreme habitats, planktonic microbial communities were abundant and mostly diverse with the presence of previously unidentified taxa.     

宏基因组学在未培养微生物研究中的应用

自然环境中约99%的微生物不能用传统的分离培养方法获得其纯培养。随着宏基因组技术的出现,人们可以对这一庞大的未知世界进行多方面的研究,包括微生物的生理、生态及其基因功能等。利用这一技术,研究者已经对地球上的许多生境进行了研究,并取得了很多新的成就。简要概述这一技术在研究未培养微生物方面的应用。     

宏基因组技术在开发极端环境未培养微生物中的应用

人类对自然环境中约99％的微生物不能用传统的方法进行纯培养,对于极端环境中的微生物更是知之甚少.随着宏基因组技术的出现,人们可对选一庞大的未知世界进行多方面研究.目前研究者利用这一技术已经对地球上的多种极端生境进行了研究,并取得了很多新的成就.简要概述这一技术在极端环境未培养微生物研究中的应用.     

Growth kinetics of microorganisms with various ecological strategies in a dialysis culture at low specific growth rates

A dialysis culture was found to be most suitable for studying the metabolism of microorganisms at a low specific growth rate. The biomass of all microorganisms studied in the dialysis culture increased with time in a linear fashion; hence, the energy spent for growth decreased in proportion to a decrease in the specific growth rate. Microorganisms growing in oligotrophous environment (Arthrobacter globiformis and Lipomyces tetrasporus ) spent much less energy comparing to microorganisms from eutrophic habitats (Pseudomonas fluorescens and Debaryomyces formicarius ).     

Distribution of microorganisms lysing Pseudomonas aeruginosa in reservoirs and soil

Various natural habitats were found to contain microorganisms producing lytic spots around their own colonies when grown on a lawn of viable Pseudomonas aeruginosa cells at 29 and 45 degrees C. The incidence of such microorganisms in water and soil was studied in quantitative terms. Contaminated waters with predominating Gram-negative heterotrophs and a high number of pseudomonades were shown to be an optimal source for the isolation of microorganisms causing the lysis of P. aeruginosa growing at 29 degrees C. Microorganisms responsible for the lysis of P. aeruginosa at 45 degrees C are abundant in the soil of mixed and foliage forests.     

The microbial diversity of inland waters

The conservation and sustainable use of freshwater resources is of global importance. Microorganisms are not only the most abundant organisms in natural freshwater systems, but are also key players in ecological processes controlling water quality. Detailed knowledge of the diversity and function of microorganisms dwelling in freshwater habitats is an essential prerequisite for the sustainable management of freshwater resources. Freshwater systems are inhabited by microbial communities that are indigenous to this habitat type and usually do not occur in marine systems, saline inland waters and terrestrial habitats. Despite recent advances in the characterization of the diversity of freshwater microorganisms, knowledge essential for a holistic understanding of their ecological roles is still lacking.     

Psychrophilic yeasts from worldwide glacial habitats: diversity, adaptation strategies and biotechnological potential

Glacial habitats (cryosphere) include some of the largest unexplored and extreme biospheres on Earth. These habitats harbor a wide diversity of psychrophilic prokaryotic and eukaryotic microorganisms. These highly specialized microorganisms have developed adaptation strategies to overcome the direct and indirect life-endangering influence of low temperatures. For many years Antarctica has been the geographic area preferred by microbiologists for studying the diversity of psychrophilic microorganisms (including yeasts). However, there have been an increasing number of studies on psychrophilic yeasts sharing the non-Antarctic cryosphere. The present paper provides an overview of the distribution and adaptation strategies of psychrophilic yeasts worldwide. Attention is also focused on their biotechnological potential, especially on their exploitation as a source of cold-active enzymes and for bioremediation purposes.     

Gut content identification of larvae of the Anopheles gambiae complex in western Kenya using a barcoding approach

Although larvae feeding and food source are vital to the development, survival and population regulation of African malaria vectors, the prey organisms of Anopheles gambiae larvae in the natural environment have not been well studied. This study used a molecular barcoding approach to investigate the natural diets of Anopheles gambiae s.l. larvae in western Kenya. Gut contents from third- and fourth-instar larvae from natural habitats were dissected and DNA was extracted. The 18S ribosomal DNA gene was amplified, the resulting clones were screened using a restriction fragment length polymorphism method and nonmosquito clones were sequenced. Homology search and phylogenetic analyses were then conducted using the sequences of non-mosquito clones to identify the putative microorganisms ingested. The phylogenetic analyses clustered ingested microorganisms in four clades, including two clades of green algae (Chlorophyta, Chlorophyceae Class, Chlamydomonadales and Chlorococcales families), one fungal clade, and one unknown eukaryote clade. In parallel, using the same approach, an analysis of the biodiversity present in the larval habitats was carried out. This present study demonstrated the feasibility of the barcoding approach to infer the natural diets of Anopheles gambiae larvae. Our analysis suggests that despite the wide range of microorganisms available in natural habitats, mosquito larvae fed on specific groups of algae. The novel tools developed from this study can be used to improve our understanding of the larval ecology of African malaria vectors and to facilitate the development of new mosquito control tools.