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1.
对采自湖北神农架大九湖泥炭地泥炭藓(Sphagnum palustre)样品进行了不同预处理,之后提取微生物基因组DNA,构建克隆文库进而对泥炭藓共生菌的群落结构进行分析.菌落培养实验和荧光定量PCR结果显示,双氧水能杀死泥炭藓表面附生的微生物及破坏部分DNA,为研究泥炭藓内共生细菌提供一定的途径.群落组成分析结果表明双氧水处理后,所获得的细菌克隆文库的群落特征发生了改变,主要表现在细菌种类的减少及各菌门所占比率的变化上:NTX-0中酸杆菌门(Acidobacteria)和变形杆菌门(Proteaobacteria)百分比含量分别位居第一和第二,而经过双氧水进行表面除菌后NTX-0-degerming中变形菌门(Proteobacteria)占了绝对优势;而在NTX-2-degerming中,蓝细菌门(Cyanobacteria)占绝对主导地位,细菌的群落多样性明显降低,细菌种类减少.系统发育分析表明与泥炭藓内共生的细菌一方面能适应大九湖泥炭湿地酸性、贫营养的环境,另一方面能为泥炭藓提供碳源、氮源,从而参与泥炭湿地的元素循环.尤其值得注意的是在内共生菌中发现了Ⅱ型甲烷氧化菌,证实了甲烷氧化菌与泥炭藓的内共生关系,暗示着这类细菌通过自身的代谢进而影响全球碳循环的潜在意义.此外,首次报道了利用细菌的通用引物扩增出了大量泥炭藓叶绿体的序列,这可能为叶绿体内共生学说提供佐证. 相似文献
2.
深海热液口由于剧烈的温度(可达到400℃以上)、pH和化学梯度,成为地球生命起源和演化研究的焦点,海底热液口生命系统为人类提供了一个探索深部生命及生命起源和进化的窗口.本文主要开展了瓜伊马斯深海热液口高温环境下沉积物和烟囱样品中古菌多样性的研究.采用实时荧光定量PCR首先对样品中古菌进行了定量,发现沉积物和烟囱两个样品都含有高丰度的古菌,沉积物和烟囱中古菌分别达到1.47×109拷贝数/g和5.29× 108拷贝数/g(湿重).通过核糖体小亚基16S rRNA基因的PCR扩增,文库构建和系统发育分析,发现沉积物和烟囱样品中的古菌类群多数是嗜热和超嗜热微生物,但两个样品中的古菌群落组成差异很大:沉积物以泉古菌门为主,优势菌群为Miscellaneous Crenarchaeota Group (MCG)和Hot Water Crenarchaeota Group Ⅰ(HWCG Ⅰ);烟囱样品则主要是广古菌门类群,其中以Thermococcales,Marine Benthic Group D (MBGD)/Deep Hydrothermal Vent Euryarchaeota 1(DHVE 1)为主.在沉积物样品中发现了一个新的MCG类群,命名为MCG-H,可能是MCG的高温独特类群.研究揭示,在瓜伊马斯深海热液口烟囱和沉积物中都包含有丰富的古菌类群包括未被发现的新类群,对瓜伊马斯深海热液口古菌分布和多样性的研究将为进一步深入的古菌生理功能和演化的研究提供基础. 相似文献
3.
深海热液喷口生物群落研究进展 总被引：1，自引：0，他引：1
近年来深海热液喷口生物群落的研究取得了大量的成果。通过调查发现,除温度外,环境化学参数、地理位置、喷口类型、热液活动周期、生物可利用率等因素都对深海热液喷口生物群落分布产生影响。随着实验室热液微生物的分离、培养成功,一些新的属种及其特殊的生理特征被发现。分子生物学技术的发展,使得对于深海热液生物基因测序、基因功能的研究和表达,功能基因对微生物生理功能的调控作用,动物与微生物之间的共生关系,生物对极端环境的适应机制等问题的研究都能够进行。对于目前不能进行实验室分离培养的微生物,通过基因组分析,也能够了解其群落结构。不同的深海热液喷口,其病毒的类型、分布、丰度以及病毒对热液生态系统的影响是不同的。通过这些研究,科学家探讨了热液喷口环境中生物群落的能量合成与代谢途径的相关理论,并提出了生命有可能起源于热液喷口环境的假说。 相似文献
4.
5.
深海化能合成生态系统(ChEss)是当前最大的国际海洋生物多样性研究计划--国际海洋生物普查计划的现场研究项目之一.深海化能合成生态系统主要包括热液、冷泉、鲸骨生态系统以及由其他高度还原型生境形成的生态系统.确定上述系统动物区系间的进化和生态学关系,对于了解全球尺度上化能合成生态系统物种分布的形成过程至关重要.重点介绍深海化能合成生态系统科学计划发起的背景、研究内容和目标、研究区域、研究技术与方法以及当前在该领域的研究进展和展望,综合国际上在深海化能合成生态系统生物地理学和生物多样性方面的最新进展,了解其中的驱动过程,以期为我国在深海化能合成生态系统、极端环境下的生物多样性和生物地理学研究提供参考. 相似文献
6.
共生生金菌的生长具有周期性的变化特征，与锰相互作用也表现出了周期性的变化规律。该细菌影响着含锰溶液体系的ｐＨ和Ｅｈ，能将低价态的锰氧化为高价态的锰。细菌氧化锰主要借助于各种酶和不同代谢物的作用而完成。 相似文献
7.
《地球科学进展》2017,(7)
深海是地球上最重要的极端环境之一,发育了数量巨大的极端微生物。它们独特的生存环境、生理结构、代谢机制和共生关系成为探讨生命起源及寻找外太空生命的关键。尽管从生物学角度对极端微生物已开展了大量研究,但深海热液系统对极端微生物演化的影响仍不甚清楚。因此,在总结深海极端的理化环境和地质环境特征的基础上,分析了海底热液活动的分布特征、形成机理及其对周围生物群落种类、分布和演替规律的巨大影响。重点探讨了热液环境下各种极端微生物的生命形式及其对深海营养物质循环和生态系统演化的重要意义。目前,极端环境与生命过程的研究仍处于初级阶段,亟待加强深海原位探测和分子生物学技术的研发以及多学科交叉研究。 相似文献
8.
本次研究对南海冷泉活动区福尔摩沙脊(F站位)、海马冷泉环境中与甲烷有氧氧化菌共生的贻贝(分别为Bathymodiolus platifrons和Gigantidas haimaensis),以及与硫氧化菌共生的蛤(Archivesica marissinica)腮组织中的单不饱和脂肪酸进行了结构鉴定.结果发现,贻贝鳃组织中存在C16:1ω9、C16:1ω8和C18:1ω8脂肪酸,同时C16:1ω8的含量远远高于C18:1ω8,这说明与贻贝共生的为Ⅰ型甲烷有氧氧化菌.在蛤腮组织中,单不饱和脂肪酸C16:1ω7、C18:1ω7和C20:1ω7含量极高,表明ω7脂肪酸来源于硫氧化菌.同时,贻贝和蛤鳃中含有大量多不饱和脂肪酸,如C20:2和C22:2.在同一样品中来源于共生菌的单不饱和脂肪酸和来源于宿主的多不饱和脂肪酸具有相近的δ13C值,表明宿主从共生菌或共生菌代谢产物中获得碳源和营养.Ⅰ型甲烷有氧氧化菌在贻贝腮组织中广泛存在,指示F站位和海马冷泉活动区冷泉流体渗漏强度较弱.确定单不饱和脂肪酸的类型是判断双壳共生菌种类的基础.双壳类共生菌类型的识别,可以帮助理解共生体与宿主之间碳源和能量的转化关系、冷泉环境中甲烷的消耗过程如碳同化途径、碳循环等. 相似文献
9.
病毒对海洋细菌代谢的影响及其生物地球化学效应 总被引：1，自引：1，他引：0
病毒是海洋生态系统中丰度最高的生命形式,其中超过90%属于浮游细菌(细菌和古菌)病毒,是海洋生态系统的重要参与者和海洋生物地球化学循环的重要驱动力。作为海洋浮游细菌主要的致死因子之一,病毒通过裂解宿主释放出大量的有机物和营养盐,调控宿主群落的代谢行为,进而影响生物地球化学循环。同时,伴随侵染的发生,病毒挟持宿主细胞的代谢系统完成自身的生命周期,从而改变宿主胞内的代谢途径和代谢产物。概述了病毒在个体层面和群落层面对海洋浮游细菌代谢的影响,及其对海洋元素循环的作用,评估了气候变化、环境因子对病毒调控细菌代谢的潜在影响,有助于人们对微生物参与的海洋生物地球化学循环的全面认识。 相似文献
10.
冻融循环对青藏高原腹地不同生态系统土壤细菌群落结构的影响 总被引：6，自引：5，他引：1
通过构建16S rRNA基因克隆文库,研究了冻融循环对青藏高原腹地北麓河的高寒沼泽草甸和高寒沙化草原两种不同生态系统土壤细菌群落结构的影响. 结果表明: α-、 β-、 γ- 和δ-变形菌门(α-、 β-、 γ- 和δ-Proteobacteria)、 酸杆菌门(Acidobacteria)、 放线菌门(Actinobacteria)、 拟杆菌门(Bacteroidetes)和浮霉菌门(Planctomycetes)为两个生态系统土壤共有的细菌类群, 其中, 变形菌门、 酸杆菌门及浮霉菌门细菌为研究区域优势菌, 而厚壁菌门(Firmicutes)为高寒沼泽草甸土壤所特有, 疣微菌门(Verrucomicrobia)和绿弯菌门(Chloroflexi)细菌是高寒沙化草原土壤特有的细菌类群, 表明青藏高原腹地两种生态系统土壤具有丰富的细菌多样性. 冻融循环会降低区域土壤的细菌多样性, 随冻融循环, 高寒沼泽草甸和高寒沙化草原生态系统土壤放线菌门丰度均呈现下降趋势, 但大部分细菌随冻融循环的变化在两种生态类型中呈现不同的变化规律, 结果说明冻融循环对于不同生态系统土壤细菌群落结构的影响既存在相似性, 也存在着较大的差异. 相似文献
11.
The molecular organic compounds have been identified by gas chromatography (GC) and GC-mass spectrometry (GC-MS) from Mesoproterozoic rocks in the Xuanlong depression in North China. The main saturated compounds are n-alkanes, monomethylalkanes, n-alkylcyclohexanes, acyclic isoprenoids, and hopanes. The dominant lower-molecular-weight n-alkanes are indicative of the main contribution of microorganisms, in particular, the chemosynthetic bacteria. The presence of abundant monomethylalkanes (mid- and end-branched) and the long chained (>C20) acyclic isoprenoids indicates the existence of abundant bacteria and/or archaea in ancient oceans. The low abundance of pristane and phytane is suggestive of the relatively low abundance of photosynthetic autotrophs in comparison with chemosynthetic bacteria in the Mesoproterozoic oceans in North China. The sedimentary environmental condition is suboxic/anoxic, as indicated by the low value of the Pr/Ph ratio as well as the presence of abundant sulfur-bearing organic compounds, consistent with the other geochemical data in North China and elsewhere in the world. Both the composition of the primary producers and the sedimentary environmental conditions are favorable for the formation of hydrocarbon source rocks. 相似文献
12.
The comparison of the fatty acids between aerobic anoxygenic phototrophic bacteria (AAPB) and their phylogenetic relatives
has been a fascinating but yet enigmatic topic, enhancing our understanding of physiological variations between these evolutionarily
related microorganisms. Two strains of marine bacteria, both phylogenetically falling into Erythrobacter sp., were isolated from the South China Sea, and demonstrated, respectively, to be an aerobic anoxygenic phototrophic bacteria
(AAPB) (JL475) which is capable of anoxygenic photosynthesis via BChl a, and an obligate heterotroph (JL316) with a lack of BChl a, on the basis of phylogenetic analysis and pure culture cultivation. Phospholipid fatty acids (PLFA) and glycolipid fatty
acids (GLFA) of the two strains were extracted and analyzed by gas chromatographymass spectrometry. The PLFA in JL475 AAPB
are characterized by C18:1 C18:2ω7,13 and C18:1, with the C18:2ω7,13 being a specific compound for AAPB and in particular for Erythrobacter longus and some of its phylogenetically closely related relatives. The JL316 strain is characterized in PLFA by the presence of
C18:1, C16:1 and C16:0, and in particular C17:1. GLFA do not show any discrimination between the two strains. Four α,ω-dicarboxylic acids, including 1,8-octanedioic acid,
1,9-nonanedioic acid, 1,10-decanedioic acid and 1,11-undecanedioic acid, are present only in JL316 GLFA, presumably derived
from metabolic products. C14-C16 2-hydroxy fatty acids were found in the two strains, probably assuming a similar function of their LPS in outer membranes. 相似文献
13.
XIAO Zhijie LIAN Bin CHEN Jun H. Henry Teng 《中国地球化学学报》2007,26(3):252-258
A simple apparatus was designed to effectively isolate magnetotactic bacteria from soils or sediments based on their magnetotaxis. Through a series of processes including sample incubation, MTB harvesting, isolation, purification and identification, several strains of bacteria were isolated from the samples successfully. By Transmission Electron Microscopy (TEM) and Energy-Dispersive X-ray Analysis (EDXA), these bacteria were certificated to be magnetotactic bacteria. The phylogenetic relationship between the isolated magnetic strains and some known magnetotactic bacteria was inferred by the construction of phylogenetic tree based on 16SrDNA sequences. This apparatus has been proven to have the advantages of being inexpensive, simple to assemble, easy to perform and highly efficient to isolate novel magnetotactic bacteria. The research indicated that the combined approach of harvesting MTB by home-made apparatus and the method of plate colony isolation could purify and isolate magnetotactic bacteria effectively. 相似文献
14.
深海洋底热泉生态系和冷泉生物研究综述 总被引：9，自引：0，他引：9
现代海洋学、微生物学和生物学的研究表明，在深海火山活动和板块消减带所形成的地质背景下分别可能有海底热泉和冷泉的存在。在这种海底热泉和冷泉区的特殊环境中能够能海底热泉生态系的冷泉生物。它们能够依靠体内共生化学厌氧合成细菌产生营养，因而可能存在于完全缺氧的还原环境。海底热泉和冷泉生物学研究是对传统的生物学和地质学的挑战，人们还可能通过古代海底热泉和冷泉生态系的识别和分析，对涉及生命发生、生物演化、生物 相似文献
15.
冷泉流体沉积碳酸盐岩的地质地球化学特征 总被引：39，自引：3，他引：36
冷泉流体是指来自海底沉积界面之下的低温流体以喷涌和渗漏方式注入盆地, 并产生系列的物理和化学及生物作用, 这种作用及产物称为冷泉?它是继洋中脊以盆下源中高温流体的热泉被发现和研究之后的又一个新的盆地流体沉积领域?日前研究较多的是以水? 碳氢化合物 (天然气和石油) ? 硫化氢? 细粒沉积物为主要成分, 温度与海水相近的流体, 广泛发育于活动和被动大陆边缘斜坡海底?冷泉流体沉积体系发育高密度的化学自养生物群, 以碳酸盐岩和天然气水合物为主, 有少量的硫化物和硫酸盐等?冷泉碳酸盐岩的产状有丘? 结核? 硬底? 烟囱? 胶结物和小脉等, 以化学自养生物碎屑和多期次的自生碳酸盐胶结物组成的生物丘最为常见, 它在物质来源? 形成环境? 形成作用等方面与传统来源于海水碳的碳酸盐岩建隆不同, 用术语 C h e r m o h e r m 表示, 以区别于传统海水碳酸盐岩建隆术语b i o h e r m s ? l i t h o h e r m s ? p s e u d o b i o h e r m s 和 b i o s t r o m e s ?地层中石化的化学自养生物丘常是含有大量底栖生物化石的碳酸盐岩建隆产于深水相沉积地层中, 在沉积环境和相分析上出现纵向和横向的不连续, 甚至出现反常现象?矿物以镁方解石? 白云石和文石为主, 与传统的碳酸盐岩相似, 在地球化学组成上最大的区别是冷泉流体沉积碳酸盐岩的碳来源于冷泉体系中的细菌生物成因碳, 具有特别负的碳同位素值?冷泉在海底主要沿构造带和高渗透地层呈线性群, 或围绕泥火山或盐底劈顶部呈圆形或不规则状冷泉群分布,或以海底地形低凹处和峡谷转向处呈孤立冷泉形式产出?冷泉流体以沉积建造流体为主?上覆快速堆积? 成岩压实和胶结作用? 构造挤压和变形作用? 深部的后生作用和成岩作用? 海底沉积物中的天然气水合物分解作用是建造流体向上运移进入海底成为冷泉的驱动力?冷泉碳酸盐岩的沉积作用主要有胶结作用? 充填作用和生物化学沉积作用?冷泉流体中的碳主要是以甲烷为主的碳氢化合物形式存在, 经微生物作用转变为 C O2 ,最终形成冷泉碳酸盐岩? 相似文献
16.
病毒与细菌统称为微生物。病毒与细菌之害是生物生存遭遇到的最大的灾害,不仅在人类社会历史上留下了深重灾难,而且在地球生物演化史上也是大灭绝的重要推手。虽然病毒和细菌难以形成实体化石,但却以一种特殊的分子化石成为了侦探地质时期生物大灭绝的神针。本文以地球微生物学为指导,以蓝细菌和绿硫细菌分子化石为例,综合有关研究成果,解读了微生物学、病毒和细菌以及微生物岩的有关知识,帮助人们认识地球生物演化史上二次重要的大灭绝事件。本文还从人类演化过程中的农业革命,阐明了人菌共生关系及带来的启示。 相似文献
17.
Florence Schubotz Julius S. Lipp Sabine Kasten Matthias Zabel Kai-Uwe Hinrichs 《Geochimica et cosmochimica acta》2011,75(16):4377-4415
At the Chapopote Knoll in the Southern Gulf of Mexico, deposits of asphalt provide the substrate for a prolific cold seep ecosystem extensively colonized by chemosynthetic communities. This study investigates microbial life and associated biological processes within the asphalts and surrounding oil-impregnated sediments by analysis of intact polar membrane lipids (IPLs), petroleum hydrocarbons and stable carbon isotopic compositions (δ13C) of hydrocarbon gases. Asphalt samples are lightly to heavily biodegraded suggesting that petroleum-derived hydrocarbons serve as substrates for the chemosynthetic communities. Accordingly, detection of bacterial diester and diether phospholipids in asphalt samples containing finely dispersed gas hydrate suggests the presence of hydrocarbon-degrading bacteria. Biological methanogenesis contributes a substantial fraction to the methane captured as hydrate in the shallow asphalt deposits evidenced by significant depletion in 13C relative to background thermogenic methane. In sediments, petroleum migrating from the subsurface stimulates both methanogenesis and methanotrophy at a sulfate-methane transition zone 6-7 m below the seafloor. In this zone, microbial IPLs are dominated by archaeal phosphohydroxyarchaeols and archaeal diglycosidic diethers and tetraethers. Bacterial IPLs dominate surface sediments that are impregnated by severely biodegraded oil. In the sulfate-reduction zone, diagnostic IPLs indicate that sulfate-reducing bacteria (SRB) play an important role in petroleum degradation. A diverse mixture of phosphohydroxyarchaeols and mixed phospho- and diglycosidic archaeal tetraethers in shallow oil-impregnated sediments point to the presence of anaerobic methane-oxidizing ANME-2 and ANME-1 archaea, respectively, or methanogens. Archaeal IPLs increase in relative abundance with increasing sediment depth and decreasing sulfate concentrations, accompanied by a shift of archaeol-based to tetraether-based archaeal IPLs. The latter shift is suggested to be indicative of a community shift from ANME-2 and/or methanogenic archaea in shallower sediments to ANME-1/methanogenic archaea and possibly benthic archaea in deeper sediments. 相似文献
18.
Why did ancient chemosynthetic seep and vent assemblages occur in shallower water than they do today? 总被引：1，自引：0，他引：1
Cold-seep communities have relatively low diversity, are dominated by one or two taxa present in high density and high biomass
in comparison with the surrounding fauna, and are restricted to aphotic habitats. Their associated heterotrophic fauna are
usually distinctive from the fauna of their surroundings. In contrast, a more commonplace chemoautotrophically based community
occurs in shallow photic habitats. The associated heterotrophic fauna includes many of the species typical of the surrounding
communities and typically dominates abundance, whereas the species with chemoautotrophic symbionts dominate biomass. All modern
seep assemblages are deeper than 550 m. Many fossil seep assemblages occurred in water as shallow as the mid-shelf (<200 m).
In contrast, communities where species with chemoautotrophic symbionts are biomass dominants, but not numerical dominants,
are common in shallow waters at present but rarely reported in the geological record. We suggest that the absence of cold-seep
communities on the continental shelf presently is due to a combination of predation and competitive exclusion by primary consumers
limiting the presence of species dependent on chemoautotrophic symbionts. We suggest that cold-seep assemblages are more common
at shelf depths in the fossil record for two reasons: (a) The biases of preservation have accentuated their distribution by
transforming communities where species with chemoautotrophic symbionts dominate by biomass, but not numerically, into cold-seep-appearing
assemblages. (b) The importance of predation pressure and oligotrophy has varied, with decreased predation pressure accompanying
increased oligotrophy favoring cold-seep communities. We suggest that the paucity of shallow-water assemblages with species
harboring chemoautotrophic symbionts as biomass dominants in the fossil record is based on the reliance of paleoecological
analysis on numerical abundance data when energy flow analyses are required to identify these assemblages. The distinctiveness
of the fossil seep assemblage is intensified by taphonomic processes that bias the assemblage against small individuals and
epifaunal species, so that diversity declines, the small heterotrophic component of the assemblage is significantly reduced,
and the epifaunal component is minimized. The final assemblage is usually dominated by the better-preserved large infaunal
clams which perchance are also the species with chemoautotrophic symbionts. In contrast, preservation does not enhance the
distinctiveness of these chemoautotroph-harboring species in shallow water.
Received: 16 April 1998 / Accepted: 29 June 1999 相似文献
19.
Deep-sea corals live in the dark cold-water environments, the food of which that provides them with energy and nutrition is a key ecological and biogeochemical problem. Currently, the most common understanding is that their food mainly comes from organic matter produced by and deposited from surface seawater. However, more and more studies have found that they can also obtain food supply through symbiosis with a variety of chemosynthetic autotrophs and heterotrophs. Carbon and nitrogen isotopes have been used to trace and reveal the food sources of deep-sea corals. They also have been successfully used to reconstruct the phytoplankton community structure and the changes of nitrate isotopes in surface seawater in the past, thus providing valuable biogeochemical data for paleoceanographic study. However, due to the widespread existence of symbiosis with chemosynthetic autotrophs, further studies are needed to assess the reliability of organic carbon and nitrogen isotopes of deep-sea corals to reflect changes in the surface seawater. The deep-sea gorgonian coral, like those gorgonian forests recently found in the South China Sea, is relatively new and insufficiently studied in the field of deep-sea corals. Thus, basic biochemical and paleoceanographic researches on the South China Sea deep-water gorgonians will provide profound and novel insights to understanding the cold-water coral system. 相似文献
20.
Biostromes and low-relief bioherms, some of which are characterized by exceptionally large, flat specimens of larger benthic foraminifera, are common in Palaeogene and Miocene carbonates, most notably those deposited along the Neotethys Seaway and tropical Pacific islands. By incorporating insights from palaeoceanographic research and the biology of living larger benthic foraminifera, a scenario is proposed that can account for palaeontological and sedimentological features while augmenting previous interpretations. Sexual reproduction by gamete broadcasting is common in foraminiferal taxa, including extant Nummulitidae and Amphisteginidae. Resultant zygotes can develop into tiny, resistant, easily dispersed propagules that recruit in suitable benthic-environmental conditions. The role of algal symbiosis in the biology of larger benthic foraminifera is well-documented. Palaeoceanographically, such taxa proliferated during times of reduced thermal stratification of the oceans. In regions with exceptionally clear, nutrient-depleted waters, ‘twilight-zone’ light penetration was sufficient, at least intermittently, to support some photosynthesis. On outer-shelf or promontory sites at depths of ca 100 to 200 m, the tiny propagules of larger benthic foraminiferal species, incorporating algal symbionts with the lowest light requirements, could have settled and recruited, growing very slowly, nourished by feeding on bacteria and the limited photosynthate produced by their algal symbionts. Under such conditions, thin microspheric individuals of one or two larger benthic foraminiferal taxa could have survived and grown slowly over several years to very large shell diameters, seldom reproducing asexually. Resulting carbonate accumulation rates would have been very slow, such that even rare disturbances by currents, major storms or internal waves could have produced evidence of winnowing and sedimentary structures. The fossil evidence of such habitats should include biostromes or possibly low-relief bioherms of low diversity assemblages characterized by abundant, exceptionally large, flat, microspheric larger benthic foraminifera. 相似文献