可培养盐碱菌多样性的研究进展

存在于高盐强碱极端环境的微生物因其独特的生命方式,引起了广泛的关注。根据盐碱环境所含的可溶性盐成分,可分为"NaCl型"和"苏打型(Na_2CO_3/NaHCO_3)"两大类,前者的碱性pH值较低而后者碱性pH值较高。本文总结了盐碱菌适宜生长条件在盐度0.5 mol/L和碱性pH 9.0之上且有效发表的标准菌株,并对这些菌株的生物多样性及生理特性进行了阐述;可培养盐碱细菌的数量及其多样性远远大于盐碱古菌,但是盐碱细菌对高盐度和强碱性p H依赖程度相对较低。盐碱细菌主要组成依次为芽孢杆菌纲(Bacilli,占总数约40%)、γ-变形菌纲(γ-Proteobacteria,30%)、梭菌纲(Clostridia,11%)、δ-变形菌纲(δ-Proteobacteria,6%)和放线菌纲(Actinobacteria,6%),而盐碱古菌主要组成为盐古菌纲(Halobacteria,92%)和甲烷微菌纲(Methanomicrobia,8%)。这些极端微生物在生物地球化学过程中或生态循环中扮演着重要的角色和功能,挖掘和利用盐碱菌具有重要意义。     

Biodiversity amongst microorganisms and its relevance

Concluding remarks from the joint IUBS/IUMS workshop on Biodiversity amongst microorganisms and its relevance held in Amsterdam on 7–8 September 1991. An international microbial ecology programme can be justified in its own right now that appropriate investigative tools have been developed. Microorganisms influence global change, and indicate global health and environmental quality. At the same time, an inventory of the world's microbial species and their properties is required, together with associated culture collections and genomes. Sampling methods need to be standardized, both for species and functions. Extreme environments are a particularly rich source of microbial genomes, and endangered habitats should be sampled as a matter of priority. Cataloguing and conserving the world's microbial biodiversity is justifiable and scientifically important.     

Studying marine microorganisms from space

Microorganisms are but a few micrometers in diameter and are not visible to the naked eye. Yet, the large numbers of microorganisms present in the oceans and the global impact of their activities make it possible to observe them from space. Here a few examples of how microorganisms can be studied from satellites are presented. The first case is the best known: the main pigment used in photosynthesis (chlorophyll a) can be determined from satellites. These kinds of studies have contributed a tremendous amount of understanding about the distribution and dynamics of primary production in the oceans. Two other examples will concern analysis of heterotrophic prokaryotic production and estimates of dimethyl sulfide (DMS) concentration and flux to the atmosphere. These three processes are of fundamental importance for the functioning of the biosphere. Marine microbes carry out about half of the total primary production in the planet. A substantial fraction of the respiration in the oceans is due to the activity of heterotrophic prokaryotes. Finally, the flux of DMS to the atmosphere is believed to constitute one of the mechanisms by which the biota can regulate climate. The global implications of microbial processes in the oceans can only be addressed with the help of satellites. Electronic Publication     

Biodiversity of cryopegs in permafrost

This study describes the biodiversity of the indigenous microbial community in the sodium-chloride water brines (cryopegs) derived from ancient marine sediments and sandwiched within permafrost 100-120,000 years ago after the Arctic Ocean regression. Cryopegs remain liquid at the in situ temperature of -9 to -11 degrees C and make up the only habitat on the Earth that is characterized by permanently subzero temperatures, high salinity, and the absence of external influence during geological time. From these cryopegs, anaerobic and aerobic, spore-less and spore-forming, halotolerant and halophilic, psychrophilic and psychrotrophic bacteria, mycelial fungi and yeast were isolated and their activity was detected below 0 degrees C.     

植物内生菌是有待深入开发的资源宝库

植物内生菌是指那些在其生活史的一定阶段或者全部阶段生活于健康植物各种组织和器官内部的真菌或者细菌,被感染的宿主植物(至少是暂时)不表现出外在症状。在长期的协同进化过程中,大部分植物内生菌都与植物形成了互惠互利的关系,在从宿主那里获得稳定的生活环境的同时,可增强或赋予宿主抗病、抗干旱、固氮等能力,或通过其代谢产物促进植物的生长;有些内生菌还被发现能够产生与宿主相同或相似的活性物质。因此对植物内生菌的研究从20     

中国东海海洋微生物种群多样性初步研究

以东海海洋微生物群落为研究对象,用稀释平板分离法,从海泥和海水中得到542株分离物。随机选取58株发酵培养,将所有发酵菌株的16S rDNA基因扩增,并用限制性内切酶HinfI对PCR产物进行ARDRA(Amplified rDNA restriction analysis)多态性分析,共得到16种不同的操作分类单元(Operational Taxonom ic Un it,OTU)。其中OTU5和OTU7所包含的菌株分别占总分离物的32.7%和19.0%,为优势分离物。优势分离物的ER IC-PCR基因组指纹图分析表明,前者的19株分离物共有12种不同的指纹图类型,而后者的11株分离物有4种。结果显示,东海海域的海水和底泥具有明显的微生物种群多样性特征。     

Prospecting Anticancer Compounds in Actinomycetes Recovered from the Sediments of Saint Peter and Saint Paul's Archipelago,Brazil

Saint Peter and Saint Paul's Archipelago is a collection of 15 islets and rocks remotely located in the equatorial Atlantic Ocean. In this particular site, the present project intended to assess the biodiversity and biotechnological potential of bacteria from the actinomycete group. This study presents the first results of this assessment. From 21 sediment samples, 268 strains were isolated and codified as BRA followed by three numbers. Of those, 94 strains were grown in liquid media and submitted to chemical extractions with AcOEt (A), BuOH (B), and MeOH (M). A total of 224 extracts were screened for their cytotoxic activity and 41 were significantly active against HCT‐116 cancer cells. The obtained IC₅₀ values ranged from 0.04 to 31.55 μg/ml. The HR‐LC/MS dereplication analysis of the active extracts showed the occurrence of several known anticancer compounds. Individual compounds, identified using HR‐MS combined with analysis of the AntiMarin database, included saliniketals A and B, piericidins A and C and glucopiericidin A, staurosporine, N‐methylstaurosporine, hydroxydimethyl‐staurosporine and N‐carbamoylstaurosporine, salinisporamycin A, and rifamycins S and B. BRA‐199, identified as Streptomyces sp., was submitted to bioassay‐guided fractionation, leading to isolation of the bioactive piericidins A and C, glucopiericidin, and three known diketopiperazines, cyclo(l ‐Phe‐trans‐4‐OH‐l ‐Pro), cyclo(l ‐Phe‐l ‐Pro), and cyclo(l ‐Trp‐l ‐Pro).     

Functional diversity and community structure of microorganisms in uncontaminated and creosote-contaminated soils as determined by sole-carbon-source-utilization

Functional diversities of microorganisms from uncontaminated and creosote-contaminated soils were assessed using sole-carbon source-utilization patterns. The microorganisms were extracted from soil samples and inoculated into Gram-negative Biolog plates incubated at 23°C. Measurement of Shannon diversity, richness, and evenness indices, principal component analysis (PCA), and colour development rank (CDR) plots were based upon substrate utilization. Calculations incorporated data from both the 95 regular Gram-negative Biolog microplate wells and a selection of 23 carbon substrates that are included on Biolog Ecoplates. There did not appear to be significant differences in Shannon diversity and richness indices, PCA, or CDR plots between aminated and creosote-contaminated soils. Significant differences in Shannon diversity and evenness indices that were apparent with the use of the 23 ecologically relevant microplate wells were mostly absent based on calculations that incorporated the regular 95 Gram-negative Biolog microplate wells. Resolution of microbial communities by PCA, however, appeared to be reduced by the use of the 23 Biolog microplate wells compared to the regular 95 carbon sources.     

Yeasts from Tierra Del Fuego Province (Argentina): Biodiversity,Characterization and Bioprospection of Hydrolytic Enzymes

Abstract

Antarctic and sub-Antarctic regions are – with Polar Regions, mountains and the deep sea – the most extreme environments on Earth because of its low temperatures, dryness, high incidence of solar radiation and low nutrient availability. Nevertheless, microorganisms have successfully colonized these regions. In this study, culturable yeasts from soil samples collected from two different locations, a human-impacted area (Encerrada Bay) and a largely pristine and naturally vegetated area near Lago Escondido city (54°39′0″S, 67°46′48″W) from Tierra del Fuego province, Argentina were identified and characterized at different levels. They were characterized and classified as psychrotolerant and were considered as moderately halotolerant because of their ability to grow in the presence of 1.5?M of NaCl. Yeasts from phylum Ascomycota were affiliated to five genera: Candida, Yarrowia, Debaryomyces, Nadsonia, and Wickerhamiella, whereas from phylum Basidiomycota yeasts were affiliated to six genera: Naganishia, Rhodotorula, Leucosporidum, Tausonia, Cystofilobasidium, and Apiotrichum. Most of the yeasts demonstrated at least one extracellular enzymatic activity (mainly β-glucosidase, esterase, and protease activities). One isolate identified as Tausonia pullulans showed significant activity across the eight enzyme types tested. In light of these findings, Tierra del Fuego province could be considered as a cold environment with a potential source of cold-adapted yeasts producing industrially relevant cold-active enzymes.     

Biodiversity and wetlands

The implications of the Biodiversity Convention of the UNCED Conference in Rio are discussed in terms of the obligations of participating states. The importance of biodiversity is outlined with special reference to wetland ecosystems. The values of wetlands and wetland biodiversity are discussed and a possible classification strategy for their conservation and wise use is suggested.Corresponding Editor: R.E. Turner     

Isolation and characterization of marine-derived Mucor sp. for the fermentative production of tyrosol

An investigation of marine red algae surface-associated fungal communities led to the isolation of a previously undescribed Mucor strain. Many characteristic features of the genus Mucor, including sporangiophores, sporangium, sporangiospores and columellae, were apparent in scanning electron microscope (SEM) images of the isolated strain. The sequence of the internal transcribed spacer (ITS) rDNA revealed that the strain exhibits 97% homology to the genus Mucor. In a search for active compounds isolated by an ethyl acetate extract of the strain, tyrosol (2-(4-hydroxyphenyl) ethanol) was identified as a major secondary metabolite present in the culture broth. Remarkably, the tyrosol production level was considerably higher than that of reported tyrosol producing microorganisms. The optimal conditions for the fermentative production of tyrosol by the new strain were identified, including culture media, incubation period, temperature and pH. These findings clearly demonstrate that this novel strain has the potential for development as a natural source of tyrosol for industrial purposes.     

深海微生物多样性

海洋面积约占地球总面积的70％,平均深度3,800 m,海底平均压力38 MPa,海水以下更是包含有物理化学性质迥异的多种地质结构,例如海洋沉积物、洋壳、热液口以及冷泉等.这些性质迥异的地质结构环境造就了丰富的生物多样性,构成了地球上最大的微生物生态系统.深海海水中最主要的微生物类群是α-,γ-变形菌(Alpha-&Gammaproteobacteria),以及海洋古菌群I(Marine Group I).深海沉积物中微生物含量与有机物含量和距离大陆板块的距离相关,以异养微生物为主.深海冷泉区富集了厌氧甲烷氧化古菌ANME和硫酸盐还原菌(Deltaproteobacteria);深海热液区由于具有化学物质的多样性和快速的动态变化而导致形成微生物的高度多样性.洋壳主要由基性、超基性岩构成,含有丰富的矿物,其中不乏参与铁、锰、硫等关键代谢反应的化能自养微生物.同时,由于环境中99％以上的微生物没有已培养的亲缘种,因此对深海微生物的多样性、生理功能特性以及生物地球化学作用的理解和研究仍然存在巨大的挑战.本文将尝试从不同的深海环境分区来综述深海海水、沉积物、洋壳,以及冷泉区和热液口等特殊生态环境中微生物的分布和多样性.     

Enrichment of slow-growing marine microorganisms from mixed cultures using gel microdrop (GMD) growth assay and fluorescence-activated cell sorting

Encapsulation of cells in agarose gel microdrops (GMDs) combined with fluorescence-activated cell sorting (FACS) has been used previously to analyze and recover specific mammalian, bacterial, and yeast cell populations. Recently, we have developed a method to enrich mixed bacterial populations for slow-growing microorganisms using the GMD Growth Assay combined with fluorochrome staining and flow cytometry. Here, we demonstrate the feasibility of using this experimental approach to detect clonogenic growth of individual bacteria within GMDs in less than 3 h and to separate subpopulations based on differential growth rates. We show that after sorting, organisms remain viable and can be propagated in culture for further analysis.     

生物多样性的生态系统功能

本文从以下几个方面综述了生物多样性对生态系统功能和作用的影响 :第一 ,几个关于物种在生态系统中的不同地位和生物多样性如何影响生态系统功能的假说 ;第二 ,生物多样性与生态系统的稳定性 ;第三 ,生物多样性如何影响生态系统的生产力 ;第四 ,生物多样性对生态系统可持续性的影响。此外还提出了几个需要继续探讨和关注的问题     

一株纤维素分解菌的分离与筛选

以新华滤纸为唯一碳源,从垃圾堆肥中筛选能够分解纤维素的菌株共39株,采用刚果红鉴别培养基进行识别,获取透明圈较大的菌株10株,在此基础上,进行液体培养,测定酶活,得到1株酶活较高的曲霉B－6（Aspergillus sp)。将B－6与绿色木霉（Trichoderma sp)AS3.3711进行了参比试验,比对筛选工作进行评定,经过固体,液体发酵对比试验,发现B－6与AS3．371有相近的产酶性能,B－6在固,液发酵中酶活分别达到39．2IU,14．9IU,而S3．3711则分别为16．6IU与15．7IU,且B－6较AS3．3711有更强的液化CMC的能力,B－6在24h内即能使3％CMC完全液化,而S3．3711则需96h。     

环境微生物培养新技术的研究进展

遍布于地球上各种生境中的微生物具有丰富的物种多样性.迄今为止,能够在实验室条件下培养的微生物仅仅是其中的一小部分,微生物物种的绝大多数还都难以在现有培养技术和条件下进行繁殖和生长.人们把那些尚未在实验室获得培养生长的微生物称之为未培养微生物(Uncultured microorganisms).本文概述了一些制约微生物培养生长的影响因素,重点介绍了近年来出现的一些新颖独特的环境微生物培养技术和方法,包括稀释培养法、高通量培养技术、模拟自然环境的扩散盒技术、土壤基质膜装置、细胞微囊包埋技术等.此外,本文还总结了通过改善微生物培养条件、设计开发新型的微生物培养基等方面取得的令人瞩目的进展.这些新颖培养技术和培养方法的出现,显著提高了微生物的可培养性,发现和鉴定了许多新的微生物物种,极大地丰富了可培养微生物的多样性和微生物资源,并为深入研究和开发微生物奠定了良好的资源研究基础.     

海洋微生物生物活性物质研究

海洋微生物以其分类的多样性和遗传背景的特征而具有产生新型生物活性物质的巨大潜力,本文对海洋微生物产生的生物活性物质的研究进展进行了综述,从报道的研究结果看,占海洋微生物主导地位的海洋细菌产生的活性物质种类最为丰富;海洋真菌和海洋放射线菌虽非海洋微生物中的主要菌群,但其产生新型生物活性物质的潜能不可低估。此外,目前研究主要局限于那些在常规条件下易于培养的微生物类群,今后的之一是对于非可培养海洋微生物产生的生物活性物质的探索,我国应充分利用国内海洋微生物资源优势加强这一领域的研究。     

Biodiversity loss and the taxonomic bottleneck: emerging biodiversity science

Human domination of the Earth has resulted in dramatic changes to global and local patterns of biodiversity. Biodiversity is critical to human sustainability because it drives the ecosystem services that provide the core of our life-support system. As we, the human species, are the primary factor leading to the decline in biodiversity, we need detailed information about the biodiversity and species composition of specific locations in order to understand how different species contribute to ecosystem services and how humans can sustainably conserve and manage biodiversity. Taxonomy and ecology, two fundamental sciences that generate the knowledge about biodiversity, are associated with a number of limitations that prevent them from providing the information needed to fully understand the relevance of biodiversity in its entirety for human sustainability: (1) biodiversity conservation strategies that tend to be overly focused on research and policy on a global scale with little impact on local biodiversity; (2) the small knowledge base of extant global biodiversity; (3) a lack of much-needed site-specific data on the species composition of communities in human-dominated landscapes, which hinders ecosystem management and biodiversity conservation; (4) biodiversity studies with a lack of taxonomic precision; (5) a lack of taxonomic expertise and trained taxonomists; (6) a taxonomic bottleneck in biodiversity inventory and assessment; and (7) neglect of taxonomic resources and a lack of taxonomic service infrastructure for biodiversity science. These limitations are directly related to contemporary trends in research, conservation strategies, environmental stewardship, environmental education, sustainable development, and local site-specific conservation. Today’s biological knowledge is built on the known global biodiversity, which represents barely 20% of what is currently extant (commonly accepted estimate of 10 million species) on planet Earth. Much remains unexplored and unknown, particularly in hotspots regions of Africa, South Eastern Asia, and South and Central America, including many developing or underdeveloped countries, where localized biodiversity is scarcely studied or described. "Backyard biodiversity", defined as local biodiversity near human habitation, refers to the natural resources and capital for ecosystem services at the grassroots level, which urgently needs to be explored, documented, and conserved as it is the backbone of sustainable economic development in these countries. Beginning with early identification and documentation of local flora and fauna, taxonomy has documented global biodiversity and natural history based on the collection of "backyard biodiversity" specimens worldwide. However, this branch of science suffered a continuous decline in the latter half of the twentieth century, and has now reached a point of potential demise. At present there are very few professional taxonomists and trained local parataxonomists worldwide, while the need for, and demands on, taxonomic services by conservation and resource management communities are rapidly increasing. Systematic collections, the material basis of biodiversity information, have been neglected and abandoned, particularly at institutions of higher learning. Considering the rapid increase in the human population and urbanization, human sustainability requires new conceptual and practical approaches to refocusing and energizing the study of the biodiversity that is the core of natural resources for sustainable development and biotic capital for sustaining our life-support system. In this paper we aim to document and extrapolate the essence of biodiversity, discuss the state and nature of taxonomic demise, the trends of recent biodiversity studies, and suggest reasonable approaches to a biodiversity science to facilitate the expansion of global biodiversity knowledge and to create useful data on backyard biodiversity worldwide towards human sustainability.