宜宾浓香型白酒酿造过程中可培养细菌的系统发育多样性

【目的】为较系统地了解宜宾浓香型白酒酿造过程中可培养细菌的多样性,得到一些潜在的微生物资源。【方法】采用改良的NA培养基和高氏I号培养基分离、去除冗余,测定所得细菌纯培养物的16S rRNA基因,进行系统发育分析。【结果】分离得到603株细菌,4株菌的序列与GenBank中典型菌株序列相似性低于97%,代表着潜在新类群;599株菌与GenBank中34个属、101个种的典型菌株序列相似性大于97%,其中以Bacillus为绝对优势菌(315株),Streptomyces(121株)、Lysinibacillus(35株)、Staphylococcus(45株)为次优势菌,其余各属菌株均在10株以下。而且有16个属均只检测到1株菌。【结论】宜宾浓香型白酒发酵过程中的细菌呈现出较为丰富的多样性和一定的稳定性。     

Molecular phylogenetic profiling of gut‐associated bacteria in larvae and adults of flesh flies

Flesh flies of the genus Sarcophaga (Diptera: Sarcophagidae) are carrion‐breeding, necrophagous insects important in medical and veterinary entomology as potential transmitters of pathogens to humans and animals. Our aim was to analyse the diversity of gut‐associated bacteria in wild‐caught larvae and adult flesh flies using culture‐dependent and culture‐independent methods. Analysis of 16S rRNA gene sequences from cultured isolates and clone libraries revealed bacteria affiliated to Proteobacteria, Actinobacteria, Firmicutes and Bacteroidetes in the guts of larval and adult flesh flies. Bacteria cultured from larval and adult flesh fly guts belonged to the genera Acinetobacter, Bacillus, Budvicia, Citrobacter, Dermacoccus, Enterococcus, Ignatzschineria, Lysinibacillus, Myroides, Pasteurella, Proteus, Providencia and Staphylococcus. Phylogenetic analysis showed clone sequences of the genera Aeromonas, Bacillus, Bradyrhizobium, Citrobacter, Clostridium, Corynebacterium, Ignatzschineria, Klebsiella, Pantoea, Propionibacterium, Proteus, Providencia, Serratia, Sporosarcina, Weissella and Wohlfahrtiimonas. Species of clinically significant genera such as Ignatzschineria and Wohlfahrtiimonas spp. were detected in both larvae and adult flesh flies. Sequence analysis of 16S rRNA gene libraries supported culture‐based results and revealed the presence of additional bacterial taxa. This study determined the diversity of gut microbiota in flesh flies, which will bolster the ability to assess microbiological risk associated with the presence of these flies. The present data thereby establish a platform for a much larger study.     

Molecular phylogenetic diversity of the microbial community associated with a high-temperature petroleum reservoir at an offshore oilfield

The microbial community and its diversity in production water from a high-temperature, water-flooded petroleum reservoir of an offshore oilfield in China were characterized by 16S rRNA gene sequence analysis. The bacterial and archaeal 16S rRNA gene clone libraries were constructed from the community DNA and, using sequence analysis, 388 bacterial and 220 archaeal randomly selected clones were clustered with 60 and 28 phylotypes, respectively. The results showed that the 16S rRNA genes of bacterial clones belonged to the divisions Firmicutes, Thermotogae, Nitrospirae and Proteobacteria, whereas the archaeal library was dominated by methanogen-like rRNA genes (Methanothermobacter, Methanobacter, Methanobrevibacter and Methanococcus), with a lower percentage of clones belonging to Thermoprotei. Thermophilic microorganisms were found in the production water, as well as mesophilic microorganisms such as Pseudomonas and Acinetobacter-like clones. The thermophilic microorganisms may be common inhabitants of geothermally heated specialized subsurface environments, which have been isolated previously from a number of high-temperature petroleum reservoirs worldwide. The mesophilic microorganisms were probably introduced into the reservoir as it was being exploited. The results of this work provide further insight into the composition of microbial communities of high-temperature petroleum reservoirs at offshore oilfields.     

一平浪盐矿古老岩盐沉积中可培养细菌的系统发育多样性研究

运用纯培养法和基于16S rRNA基因序列的系统发育分析对云南省一平浪盐矿古老岩盐沉积中可培养细菌的多样性进行了研究。用补充0.5~3.5mol/L NaCl的MBA和ISP2琼脂培养基从卤水、岩盐和盐土样品中分离到38株细菌,用细菌通用引物进行16S rRNA基因扩增和序列测定,用相关软件进行序列相似性搜索、比对和系统发育分析。结果表明,38个分离菌株可分为31个物种,属于4个大的系统发育类群(Proteobacteria,Bacteroidetes,Firmicutes,Actinobacteria)、17个科、24个属。多数菌株属于Proteobacteria门(18株,47.3%;Gamma-Proteobacteria,31.5%;Alpha-Proteobacteria,15.8%)和Firmicutes门(13株,34.2%)。这些分离菌株中,至少有3个菌株可能代表3个不同属的3个新物种:Y3、Y15和Y25分别代表Idiomarina属、Salinicoccus属和Saccharospirillum属的新物种;而菌株Y21有可能代表Staphylococcaceae科的一个新属。从以上结果可以看出,一平浪盐矿古老岩盐沉积中存在较为丰富的微生物物种多样性和系统发育多样性,并且潜藏着新的微生物资源。     

湛江硇洲岛海葵相关可培养细菌系统发育多样性

【目的】了解湛江硇洲岛海葵样品中相关可培养细菌的多样性。【方法】运用纯培养法和基于16S rRNA基因序列的系统发育分析对样品中可培养细菌多样性进行研究。【结果】用补充0～2.0 mol/L NaCl 的MA、ISP 2、NA、SWA和HAA培养基从海葵样品中分离到126株细菌,通过形态观察和部分生理生化实验去冗余,选取42株具有代表性的菌株进行基于16S rRNA基因序列的系统发育多样性分析。结果表明,42个分离菌株可分为25个物种,属于3个大的系统发育类群(Firmicutes,Gamma-Proteobacteria,Actinobacteria)、11个科、18个属。多数菌株属于Firmicutes门（17株,40.5％）和Gamma-Proteobacteria亚门（14株,33.3％）。这些分离菌株中,至少有6个菌株可能代表6个不同属的6个新物种：JSM 071004、JSM 071068、JSM 071073、JSM 072002、JSM 073008和JSM073097分别代表Bacillus、Halobacillus、Piscibacillus、Pontibacillus、Alteromonas和Nocardiopsis属的新物种。【结论】从以上结果可以看出,湛江硇洲岛海葵中存在较为丰富的微生物物种多样性和系统发育多样性,并且潜藏着较多的新的微生物类群（物种）。     

油樟内生芽孢细菌的系统发育多样性

摘要：【目的】为了解油樟产芽孢内生细菌的多样性。【方法】采用改良的牛肉膏琼脂培养基分离、去除冗余及芽孢染色,测定所得产芽孢内生细菌的16S rRNA基因,进行系统发育分析。【结果】40株产芽孢内生细菌数量占分离得到的内生细菌总数的38.1％,其中根、茎、叶中分别分离得到24株、7株和9株。16S rRNA基因序列系统发育分析结果表明,35株菌可能分属于Bacillus、Lysinibacillus、Paenibacillus属的16个种,还有5株菌的序列与数据库中典型菌株序列相似性低于97％,代表着潜在新类群的存在。【结论】从油樟3个部位分离出的产芽孢内生细菌存在明显的系统发育多样性,而且3个部位分离出的产芽孢内生细菌区系既呈现出一定程度的细菌区系相似性,又表现出器官细菌区系的特异性。     

植物叶际固氮菌研究进展

固氮菌广泛存在于植物叶际,能固定空气中的氮气,满足自身或植物的部分氮素需求。基于纯种分离和培养的传统生物学方法已经研究了部分叶际固氮菌的特性,但对叶际固氮菌的物种组成、群落结构及生态功能等方面的认识还非常有限。随着分子生物学技术的发展、微生物分子生态学研究方法的逐步成熟,人们对叶际微生物的多样性和生态功能的研究越来越深入。叶际固氮菌具有丰富的多样性,温度、湿度、光照等环境因素及植物种类和微生物互作均会影响叶际固氮菌的组成。不同于根际固氮菌,叶际固氮菌具有非专一性,且不易受化肥的影响,其在农业生产上已经表现出潜在的应用价值。为此,本文综述了农作物、森林、海域生态系统中叶际固氮菌的群落结构组成及生态功能,以及外界因素对叶际固氮系统的影响。     

青岛太平湾潮间带趋磁细菌多样性

在青岛太平湾潮间带沉积物中发现了一定量的海洋趋磁细菌,最大丰度可达350个/cm~3。透射电镜观察发现该区域趋磁细菌均为趋磁球菌。磁小体个体形状单一,皆是立方体状;磁小体排列方式多样,以链状排列为主,包括单链、双链与多链,也有少数成簇排列。EDS结果表明,磁小体成分为四氧化三铁。据估算,趋磁细菌的铁元素含量(干重)范围在0.40%—6.91%之间,平均为2.19%。通过16S rRNA基因文库的构建与测序得到了47个趋磁细菌序列,分属13个OTU。系统发育分析结果表明,它们都属于α-变形菌纲,其中9个OTU与已知最相似序列的相似性低于97%,有5个OTU与已知最相似序列的相似性低于93%,可能代表了趋磁细菌的9个新种、5个新属,说明该区域潜在的微生物新种质资源十分可观。     

Phylogenetic diversity of endolithic bacteria in Bole granite rock in Xinjiang

The endolithic environment is a ubiquitous microbial habitat for microorganisms, such as lichens, Cyanobacteria and fungi, and it provides mineral nutrients and growth surfaces. In extremely environments, such as hot and cold desert, endolithic communities are often the main form of life. More recently, endolithic microbial communities have been observed inhabiting a variety of rock types ranging from hard granite to porous rocks such as basalt, dolomite, limestone, sandstone and granites. Regardless of geographic location and rock type, each of these habitats is characterized by a subsurface microclimate that prevents endolithic microorganisms growth. Photosynthesis-based endolithic microbial communities commonly inhabit the outer millimeters to centimeters of rocks exposed to the surface. The ability to fix carbon dioxide and in some cases atmospheric dinitrogen, gives the Cyanobacteria a clear competitive advantage over heterotrophic bacteria, so it is been called the main primary producer. Light quality and intensity appear to be the main determinant of the maximum depth to which growth occurs in endolithic phototrophic communities. Valleys of Fantastic Rocks in Bole is close to Alashankou Port of Xinjiang which belongs to extreme continental climate. In order to investigate the structure, composition and diversity of endolithic bacterial community in exposed granitic porphyry in the Valleys of Fantastic Rocks, environmental DNA was directly extracted from granite rock, the 16S rRNA genes were amplified from the total DNA by PCR with bacterial-specific primers, and an endolithic bacterial clone library was constructed. Positive clones were randomly selected from the library and identified by Restriction Fragment Length Polymorphism (RFLP). The unique rRNA types clones were sequenced, analysised and then constructed phylogenetic tree. In total, 129 positive clones were screened and grouped into 46 operational taxonomic unites (OTUs). The clone coverage C value was 89.15%, indicating that most of the estimated endolithic bacterial diversity was sampled. BLAST analysis indicated that 46 OTUs were divided into seven phyla (Acidobacteria, Actinobacteria, Bacteroidetes, Chloroflexi, Cyanobacteria, Planctomycetes, Proteobacteria) and five unknown groups. Cyanobacteria (43%), especially the Gp I, form the functional basis for an endolithic bacteria community which contain a wide spectrum species of chemotrophic bacteria (33%) with mainly Actinobacteria, α-Proteobacteria, Acidobacteria. Additionally, most clones that derived from the endolithic bacteria clone library showed high similarity to the sequence deposited in GenBank database with 97%–99%. Besides, 35% of the clones showed less than 97% of sequence similarity, of which 12% sequences were affiliated to genus Rubrobacter. The results suggested that endolithic bacteria in Valleys of Fantastic Rocks in Xinjiang were highly diverse in species richness, and maybe have a diversity of potential novel species and lineages.     

基于线粒体16S rRNA和COI基因序列探讨对虾属(Penaeus)物种系统发生关系

有关对虾属(Penaeus)的设置及其相互亲缘关系一直是分类学争论的焦点,利用线粒体16S rRNA基因片段及COI基因片段序列分析的方法,以长臂虾科的脊尾白虾(Exopalaemon carinicauda)为外群,对对虾属的6亚属23种对虾进行了分子系统学研究。经ClustalX多重比对和MEGA4.0软件分析,得到种间序列的遗传距离并构建了最大简约(MP)系统树。结果表明:分子系统学数据支持Perez F等将对虾属的6个亚属提升为属级阶元的观点。囊对虾属的日本囊对虾(Marsupenaeus japonicus)和沟对虾属(Melicertus)的深沟对虾(Melicertus canaliculatus)之间的16S遗传距离只有0.007,而且COI遗传距离仅有0.065,比深沟对虾与同为沟对虾属的其他虾类遗传距离还小,说明囊对虾亚属(Marsupenaeus)和沟对虾亚属之间亲缘关系较近。另外美对虾亚属的褐美对虾(Farfantepenaeus aztec-us)和巴西美对虾(Farfantepenaeus brasiliensis)之间的16S rRNA基因序列遗传距离仅为0.012,但是与其他同亚属的虾类遗传距离相对较大,推测美对虾亚属(Farfantepenaeus)中的虾类根据亲缘关系远近和地理分布可以分为2大类群:墨西哥湾类群和南美洲类群。可以为对虾属的6个亚属的分类问题及演化提供一定的分子生物学依据。     

广西水牛瘤胃中的细菌多样性

[目的]了解广西水牛瘤胃中细菌的组成及其可能的降解纤维素细菌的主要类群。[方法]提取水牛瘤胃内容物和高效降解滤纸的水牛瘤胃内容物的富集培养物的宏基因组DNA,以宏基因组DNA为模板,扩增16S rRNA基因序列,构建该两种样品的细菌的16S rRNA基因文库。通过对16S rRNA基因序列的分析,了解这两种样品的细菌群体种类及数量。 [结果] 水牛瘤胃内容物与其富集培养物中均主要含有LGCGPB (low G+C Gram-Positive Bacteria)、CFB (Cytophaga-Flexibacter-Bacteroides)两大类菌群和少数的螺旋体菌（Spirochaetes）,且LGCGPB所占的比例都是最高的,LGCGPB在水牛瘤胃内容物细菌中的比例为56.66%,而在富集培养物细菌中的比例升高为73.33%。在水牛瘤胃内容物中,丝状杆菌（Fibrobacteres）占3.33%,但在富集培养物中未被检测到。而在富集培养物中占13.33%的变形杆菌（Proteobacteria）,在水牛瘤胃内容物中未被检测到。本研究还发现了分类地位尚未明确的一菌群（R46）。[结论]细菌类群LGCGPB、Proteobacteria可能在水牛瘤胃中的纤维素降解过程中起重要作用。此外,水牛瘤胃中的细菌组成和牦牛、牛、羊瘤胃中的细菌组成较相似但比例有所不同。     

Ecosystem productivity is associated with bacterial phylogenetic distance in surface marine waters

Understanding the link between community diversity and ecosystem function is a fundamental aspect of ecology. Systematic losses in biodiversity are widely acknowledged but the impact this may exert on ecosystem functioning remains ambiguous. There is growing evidence of a positive relationship between species richness and ecosystem productivity for terrestrial macro‐organisms, but similar links for marine micro‐organisms, which help drive global climate, are unclear. Community manipulation experiments show both positive and negative relationships for microbes. These previous studies rely, however, on artificial communities and any links between the full diversity of active bacterial communities in the environment, their phylogenetic relatedness and ecosystem function remain hitherto unexplored. Here, we test the hypothesis that productivity is associated with diversity in the metabolically active fraction of microbial communities. We show in natural assemblages of active bacteria that communities containing more distantly related members were associated with higher bacterial production. The positive phylogenetic diversity–productivity relationship was independent of community diversity calculated as the Shannon index. From our long‐term (7‐year) survey of surface marine bacterial communities, we also found that similarly, productive communities had greater phylogenetic similarity to each other, further suggesting that the traits of active bacteria are an important predictor of ecosystem productivity. Our findings demonstrate that the evolutionary history of the active fraction of a microbial community is critical for understanding their role in ecosystem functioning.     

利用改良培养基探究西太平洋海水可培养细菌多样性

[目的]西太平洋复杂的海洋生态环境孕育了其独特的生物群落,蕴含着种类丰富的海洋微生物资源.本研究基于分离培养技术探究了西太平洋海域不同水深细菌的多样性,并尝试通过改良培养基提高海洋细菌可培养性.[方法]采用改良的2216E固体培养基(IMA)、R2A固体培养基(R2A)、MBM固体培养基(MBM)、TCBS固体培养基(...     

Physiological and phylogenetic diversity of thermophilic spore-forming hydrocarbon-oxidizing bacteria from oil fields

The distribution and population density of aerobic hydrocarbon-oxidizing bacteria in the high-temperature oil fields of Western Siberia, Kazakhstan, and China were studied. Seven strains of aerobic thermophilic spore-forming bacteria were isolated from the oil fields and studied by microbiological and molecular biological methods. Based on the 16S rRNA gene sequences, phenotypic characteristics, and the results of DNA-DNA hybridization, the taxonomic affiliation of the isolates was tentatively established. The strains were assigned to the first and fifth subgroups of the genusBacillus on the phylogenetic branch of the gram-positive bacteria. Strains B and 421 were classified asB. licheniformis. Strains X and U, located betweenB. stearothermophilus andB. thermocatenulatus on the phylogenetic tree, and strains K, Sam, and 34, related but not identical toB. thermodenitrificans andB. thermoleovorans, undoubtedly represent two new species. Phylogenetically and metabolically related representatives of thermophilic bacilli were found to occur in geographically distant oil fields     

New insights into relationships between active and dormant organisms,phylogenetic diversity and ecosystem productivity

Marine microbes make up a key part of ocean food webs and drive ocean chemistry through a range of metabolic processes. A fundamental question in ecology is whether the diversity of organisms in a community shapes the ecological functions of that community. While there is substantial evidence to support a positive link between diversity and ecological productivity for macro‐organisms in terrestrial environments, this relationship has not previously been verified for marine microbial communities. One factor complicating the understanding of this relationship is that many marine microbes are dormant and are easily dispersed by ocean currents, making it difficult to ensure that the organisms found in a given environmental sample accurately reflect processes occurring in that environment. Another complication is that, due to microbes great range of genotypic and phenotypic variability, communities with distantly related species may have greater range of metabolic functions than communities have the same richness and evenness, but in which the species present are more closely related to each other. In this issue of Molecular Ecology, Galand et al. (2015) provide compelling evidence that the most metabolically active communities are those in which the nondormant portion of the microbial community has the highest phylogenetic diversity. They also illustrate that focusing on the active portion of the community allows for detection of temporal patterns in community structure that would not be otherwise evident. The authors’ point out that the presence of many dormant organisms that do not contribute to ecosystem functioning is a feature that makes microbial ecosystems fundamentally different from macro‐ecosystems and that this difference needs to be accounted for in microbial ecology theory.     

Diversity of spore‐forming bacteria in cattle manure,slaughterhouse waste and samples from biogas plants

Aims: As biowaste intended for biogas production can contain pathogenic micro‐organisms, the recommended treatment is pasteurization at 70°C for 60 min. This reduces pathogens such as Salmonella spp., whereas spore‐forming bacteria (Bacillus spp. and Clostridium spp.) survive. Most spore‐forming bacteria are harmless, but some can cause diseases such as blackleg, botulism and anthrax. In this study, the effect of the biogas process on Bacillus spp. and Clostridium spp. was investigated. Methods and Results: We analysed 97 faecal samples, 20 slaughterhouse waste samples and 60 samples collected at different stages in the biogas process. Bacillus spp. and Clostridium spp. were quantified and subcultured. The isolates were identified by biochemical methods and by 16S rRNA gene sequencing. Phylogenetic trees were constructed from the sequences obtained from isolates from the samples. Clostridium botulinum/Clostridium spp. and Clostridium sordellii were found both before and after pasteurization, but not after digestion (AD). Some of the isolated strains probably represented new members of the genera Clostridium and Bacillus. Conclusion: After digestion, the numbers of clostridia decreased, but none of the pathogenic bacteria did, whereas Bacillus spp. remained constant during the process. Significance and Impact of the Study: Biogas is gaining in importance as an energy source and because the residues are used as fertilizers, we needed to study the prevalence of pathogenic bacteria in such material.     

Characterization of culturable anaerobic bacteria from the forestomach of an eastern grey kangaroo, Macropus giganteus

AIM: To determine the culturable biodiversity of anaerobic bacteria isolated from the forestomach contents of an eastern grey kangaroo, Macropus giganteus, using phenotypic characterization and 16S rDNA sequence analysis. METHODS AND RESULTS: Bacteria from forestomach contents of an eastern grey kangaroo were isolated using anaerobic media containing milled curly Mitchell grass (Astrebla lappacea). DNA was extracted and the 16S rDNA sequenced for phylogenetic analysis. Forty bacterial isolates were obtained and placed in 17 groups based on phenotypic characteristics and restriction enzyme digestion of 16S rDNA PCR products. DNA sequencing revealed that the 17 groups comprised five known species (Clostridium butyricum, Streptococcus bovis, Clostridium sporogenes, Clostridium paraputrificum and Enterococcus avium) and 12 groups apparently representing new species, all within the phylum Firmicutes. CONCLUSIONS: Foregut contents from Australian macropod marsupials contain a microbial ecosystem with a novel bacterial biodiversity comprising a high percentage of previously unrecognized species. SIGNIFICANCE AND IMPACT OF THE STUDY: This study adds to knowledge of Australia's unique biodiversity, which may provide a future bioresource of genetic information and bacterial species of benefit to agriculture.     

Genetic diversity and phylogenetic relationships of bacteria belonging to the Ochrobactrum-Brucella group by recA and 16S rRNA gene-based comparative sequence analysis

The genetic diversity and phylogenetic interrelationships among 106 Ochrobactrum strains (O. anthropi: 72, O. intermedium: 22, O. tritici: 5, O. oryzae: 2, O. grignonense: 2, O. gallinifaecis: 1, O. lupini: 2), the type strains of the eight Brucella species and other closely related taxa were studied by recA and rrs gene (16S rRNA) comparative sequence analysis. Both markers correctly delineated the various Ochrobactrum species; however, resolution at the subspecies level was considerably higher in the recA gene-based approach. Phylogenetic analyses using neighbor-joining, parsimony, and maximum likelihood algorithms generated trees with similar topologies but the overall branching order, and also the order of the subclades, were not stable in either assay, which could be explained by generally high recA and rrs sequence similarities. Ochrobactrum and Pseudochrobactrum formed separate clades distinct from other Alphaproteobacteria with Bartonella, Agrobacterium, and Rhizobium as the closest relatives. O. gallinifaecis was the most distinct member, when compared to the type species O. anthropi, with rrs and recA similarities of 96.2% and 81.4%. Brucella species were indistinguishable, exhibiting high rrs and recA gene similarities of 98.6% and 85.5% compared with Ochrobactrum intermedium. At the protein level, all RecA sequences among the various Ochrobactrum species and between Ochrobactrum and Brucella were highly similar with only a few amino acid substitutions. O. anthropi and O. tritici were indistinguishable by means of their RecA proteins. A set of initially biochemically classified strains did not cluster within their assigned species and they either grouped within other known species or grouped as potential novel Ochrobactrum species. In further investigations, these strains were reclassified and described as novel species. In summary, Ochrobactrum is a highly diverse genus comprising several novel species. We recommend recA- in addition to rrs gene-analysis for correct species allocation and subtyping of novel Ochrobactrum isolates.     

Culturable and molecular phylogenetic diversity of microorganisms in an open-dumped,extremely acidic Pb/Zn mine tailings

A combination of cultivation-based and molecular-based approaches was used to reveal the culturable and molecular diversity of the microbes inhabiting an open-dumped Pb/Zn mine tailings that was undergoing intensive acid generation (pH 1.9). Culturable bacteria found in the extremely acidic mine tailings were Acidithiobacillus ferrooxidans, Leptospirillum ferriphilum, Sulfobacillus thermotolerans and Acidiphilium cryptum, where the number of acidophilic heterotrophs was ten times higher than that of the iron- and sulfur-oxidizing bacteria. Cloning and phylogenetic analysis revealed that, in contrast to the adjacent AMD, the mine tailings possessed a low microbial diversity with archaeal sequence types dominating the 16S rRNA gene library. Of the 141 clones examined, 132 were represented by two sequence types phylogenetically affiliated with the iron-oxidizing archaea Ferroplasma acidiphilum and three belonged to two tentative groups within the Thermoplasma lineage so far represented by only a few environmental sequences. Six clones in the library were represented by the only bacterial sequence type and were closely related to the well-described iron-oxidizer L. ferriphilum. The significant differences in the prokaryotic community structures of the extremely acidic mine tailings and the AMD associated with it highlights the importance of studying the microbial communities that are more directly involved in the iron and sulfur cycles of mine tailings.