scholarly journals Viable cold-tolerant iron-reducing microorganisms in geographically diverse subglacial environments

2017 ◽  
Vol 14 (6) ◽  
pp. 1445-1455 ◽  
Author(s):  
Sophie L. Nixon ◽  
Jon P. Telling ◽  
Jemma L. Wadham ◽  
Charles S. Cockell
Keyword(s):  
Microbial Communities ◽  
Chemical Weathering ◽  
Iron Reduction ◽  
Enrichment Culture ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Iron Cycling ◽  
Microbial Iron Reduction ◽  
Cold Tolerant ◽  
Subglacial Environments

Abstract. Subglacial environments are known to harbour metabolically diverse microbial communities. These microbial communities drive chemical weathering of underlying bedrock and influence the geochemistry of glacial meltwater. Despite its importance in weathering reactions, the microbial cycling of iron in subglacial environments, in particular the role of microbial iron reduction, is poorly understood. In this study we address the prevalence of viable iron-reducing microorganisms in subglacial sediments from five geographically isolated glaciers. Iron-reducing enrichment cultures were established with sediment from beneath Engabreen (Norway), Finsterwalderbreen (Svalbard), Leverett and Russell glaciers (Greenland), and Lower Wright Glacier (Antarctica). Rates of iron reduction were higher at 4 °C compared with 15 °C in all but one duplicated second-generation enrichment culture, indicative of cold-tolerant and perhaps cold-adapted iron reducers. Analysis of bacterial 16S rRNA genes indicates Desulfosporosinus were the dominant iron-reducing microorganisms in low-temperature Engabreen, Finsterwalderbreen and Lower Wright Glacier enrichments, and Geobacter dominated in Russell and Leverett enrichments. Results from this study suggest microbial iron reduction is widespread in subglacial environments and may have important implications for global biogeochemical iron cycling and export to marine ecosystems.

scholarly journals Viable cold-tolerant iron-reducing microorganisms in geographically-isolated subglacial environments

2016 ◽  
Author(s):  
Sophie L. Nixon ◽  
Jon Telling ◽  
Jemma L. Wadham ◽  
Charles S. Cockell
Keyword(s):  
Microbial Communities ◽  
Chemical Weathering ◽  
Iron Reduction ◽  
Enrichment Culture ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Microbial Iron Reduction ◽  
Cold Tolerant ◽  
Subglacial Environments ◽  
Geographically Isolated

Abstract. Subglacial environments are known to harbor metabolically-diverse microbial communities. These microbial communities drive chemical weathering of underlying bedrock and influence the geochemistry of glacial meltwaters. Despite its importance in weathering reactions, the microbial cycling of iron in subglacial environments, in particular the role of microbial iron reduction, is poorly understood. In this study we address the prevalence of viable iron-reducing microorganisms in subglacial sediments from five geographically isolated glaciers. Iron-reducing enrichment cultures were established with sediment from beneath Engabreen (Norway), Finsterwalderbreen (Svalbard), Leverett and Russell Glaciers (Greenland) and Lower Wright Glacier (Antarctica). Rates of iron reduction were higher at 4 °C compared with 15 °C in all but one duplicated second-generation enrichment culture, indicative of cold-tolerant and perhaps cold-adapted iron-reducers. Analysis of bacterial 16S rRNA genes indicate Desulfosporosinus were the dominant iron-reducing microorganisms in low-temperature Engabreen, Finsterwalderbreen and Lower Wright Glacier enrichments, and Geobacter dominated in Russell and Leverett enrichments. Results from this study suggest microbial iron reduction is widespread in subglacial environments, and may have important implications for global biogeochemical iron cycling and export to marine ecosystems.

scholarly journals Iron and sulfate reduction structure microbial communities in (sub-)Antarctic sediments

2021 ◽  
Author(s):  
Lea C. Wunder ◽  
David A. Aromokeye ◽  
Xiuran Yin ◽  
Tim Richter-Heitmann ◽  
Graciana Willis-Poratti ◽  
...  
Keyword(s):  
Microbial Communities ◽  
Sulfate Reduction ◽  
Marine Sediments ◽  
Iron Reduction ◽  
Environmental Changes ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Geochemical Parameters ◽  
Dissimilatory Iron Reduction ◽  
The Impact

AbstractPermanently cold marine sediments are heavily influenced by increased input of iron as a result of accelerated glacial melt, weathering, and erosion. The impact of such environmental changes on microbial communities in coastal sediments is poorly understood. We investigated geochemical parameters that shape microbial community compositions in anoxic surface sediments of four geochemically differing sites (Annenkov Trough, Church Trough, Cumberland Bay, Drygalski Trough) around South Georgia, Southern Ocean. Sulfate reduction prevails in Church Trough and iron reduction at the other sites, correlating with differing local microbial communities. Within the order Desulfuromonadales, the family Sva1033, not previously recognized for being capable of dissimilatory iron reduction, was detected at rather high relative abundances (up to 5%) while other members of Desulfuromonadales were less abundant (<0.6%). We propose that Sva1033 is capable of performing dissimilatory iron reduction in sediment incubations based on RNA stable isotope probing. Sulfate reducers, who maintain a high relative abundance of up to 30% of bacterial 16S rRNA genes at the iron reduction sites, were also active during iron reduction in the incubations. Thus, concurrent sulfate reduction is possibly masked by cryptic sulfur cycling, i.e., reoxidation or precipitation of produced sulfide at a small or undetectable pool size. Our results show the importance of iron and sulfate reduction, indicated by ferrous iron and sulfide, as processes that shape microbial communities and provide evidence for one of Sva1033’s metabolic capabilities in permanently cold marine sediments.

scholarly journals Depletion of Unwanted Nucleic Acid Templates by Selective Cleavage: LNAzymes, Catalytically Active Oligonucleotides Containing Locked Nucleic Acids, Open a New Window for Detecting Rare Microbial Community Members

2012 ◽  
Vol 79 (5) ◽  
pp. 1534-1544 ◽  
Author(s):  
Jan Dolinšek ◽  
Christiane Dorninger ◽  
Ilias Lagkouvardos ◽  
Michael Wagner ◽  
Holger Daims
Keyword(s):  
Nucleic Acid ◽  
Nucleic Acids ◽  
Microbial Communities ◽  
Enrichment Culture ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Simultaneous Application ◽  
Locked Nucleic Acids ◽  
Catalytically Active ◽  
Sequence Types

ABSTRACTMany studies of molecular microbial ecology rely on the characterization of microbial communities by PCR amplification, cloning, sequencing, and phylogenetic analysis of genes encoding rRNAs or functional marker enzymes. However, if the established clone libraries are dominated by one or a few sequence types, the cloned diversity is difficult to analyze by random clone sequencing. Here we present a novel approach to deplete unwanted sequence types from complex nucleic acid mixtures prior to cloning and downstream analyses. It employs catalytically active oligonucleotides containing locked nucleic acids (LNAzymes) for the specific cleavage of selected RNA targets. When combined within vitrotranscription and reverse transcriptase PCR, this LNAzyme-based technique can be used with DNA or RNA extracts from microbial communities. The simultaneous application of more than one specific LNAzyme allows the concurrent depletion of different sequence types from the same nucleic acid preparation. This new method was evaluated with defined mixtures of cloned 16S rRNA genes and then used to identify accompanying bacteria in an enrichment culture dominated by the nitrite oxidizer “CandidatusNitrospira defluvii.”In silicoanalysis revealed that the majority of publicly deposited rRNA-targeted oligonucleotide probes may be used as specific LNAzymes with no or only minor sequence modifications. This efficient and cost-effective approach will greatly facilitate tasks such as the identification of microbial symbionts in nucleic acid preparations dominated by plastid or mitochondrial rRNA genes from eukaryotic hosts, the detection of contaminants in microbial cultures, and the analysis of rare organisms in microbial communities of highly uneven composition.

scholarly journals Diversity and Dynamics of Seaweed Associated Microbial Communities Inhabiting the Lagoon of Venice

2020 ◽  
Vol 8 (11) ◽  
pp. 1657
Author(s):  
Abdul-Salam Juhmani ◽  
Alessandro Vezzi ◽  
Mohammad Wahsha ◽  
Alessandro Buosi ◽  
Fabio De Pascale ◽  
...  
Keyword(s):  
Microbial Communities ◽  
Bacterial Communities ◽  
Host Response ◽  
Environmental Parameters ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Nutrient Concentrations ◽  
Lagoon Of Venice ◽  
Anthropogenic Stressors ◽  
Rich Diversity

Seaweeds are a group of essential photosynthetic organisms that harbor a rich diversity of associated microbial communities with substantial functions related to host health and defense. Environmental and anthropogenic stressors may disrupt the microbial communities and their metabolic activity, leading to host physiological alterations that negatively affect seaweeds’ performance and survival. Here, the bacterial communities associated with one of the most common seaweed, Ulva laetevirens Areshough, were sampled over a year at three sites of the lagoon of Venice affected by different environmental and anthropogenic stressors. Bacterial communities were characterized through Illumina sequencing of the V4 hypervariable region of 16S rRNA genes. The study demonstrated that the seaweed associated bacterial communities at sites impacted by environmental stressors were host-specific and differed significantly from the less affected site. Furthermore, these communities were significantly distinct from those of the surrounding seawater. The bacterial communities’ composition was significantly correlated with environmental parameters (nutrient concentrations, dissolved oxygen saturation, and pH) across sites. This study showed that several more abundant bacteria on U. laetevirens at stressed sites belonged to taxa related to the host response to the stressors. Overall, environmental parameters and anthropogenic stressors were shown to substantially affect seaweed associated bacterial communities, which reflect the host response to environmental variations.

scholarly journals Habitat Elevation Shapes Microbial Community Composition and Alter the Metabolic Functions in Wild Sable (Martes zibellina) Guts

Animals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 865
Author(s):  
Lantian Su ◽  
Xinxin Liu ◽  
Guangyao Jin ◽  
Yue Ma ◽  
Haoxin Tan ◽  
...  
Keyword(s):  
Microbial Community ◽  
Environmental Factors ◽  
Microbial Communities ◽  
Community Composition ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Functional Genes ◽  
Martes Zibellina ◽  
Clear Cutting ◽  
Metabolic Functions

In recent decades, wild sable (Carnivora Mustelidae Martes zibellina) habitats, which are often natural forests, have been squeezed by anthropogenic disturbances such as clear-cutting, tilling and grazing. Sables tend to live in sloped areas with relatively harsh conditions. Here, we determine effects of environmental factors on wild sable gut microbial communities between high and low altitude habitats using Illumina Miseq sequencing of bacterial 16S rRNA genes. Our results showed that despite wild sable gut microbial community diversity being resilient to many environmental factors, community composition was sensitive to altitude. Wild sable gut microbial communities were dominated by Firmicutes (relative abundance 38.23%), followed by Actinobacteria (30.29%), and Proteobacteria (28.15%). Altitude was negatively correlated with the abundance of Firmicutes, suggesting sable likely consume more vegetarian food in lower habitats where plant diversity, temperature and vegetation coverage were greater. In addition, our functional genes prediction and qPCR results demonstrated that energy/fat processing microorganisms and functional genes are enriched with increasing altitude, which likely enhanced metabolic functions and supported wild sables to survive in elevated habitats. Overall, our results improve the knowledge of the ecological impact of habitat change, providing insights into wild animal protection at the mountain area with hash climate conditions.

scholarly journals Vaginal Microbiota of Adolescent Girls Prior to the Onset of Menarche Resemble Those of Reproductive-Age Women

mBio ◽  
2015 ◽  
Vol 6 (2) ◽  
Author(s):  
Roxana J. Hickey ◽  
Xia Zhou ◽  
Matthew L. Settles ◽  
Julie Erb ◽  
Kristin Malone ◽  
...  
Keyword(s):  
Microbial Communities ◽  
Adolescent Girls ◽  
Vaginal Microbiota ◽  
Reproductive Age ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Gardnerella Vaginalis ◽  
Bacterial Composition ◽  
Prospective Longitudinal Study ◽  
Prospective Longitudinal

ABSTRACTPuberty is an important developmental stage wherein hormonal shifts mediate the physical and physiological changes that lead to menarche, but until now, the bacterial composition of vaginal microbiota during this period has been poorly characterized. We performed a prospective longitudinal study of perimenarcheal girls to gain insight into the timing and sequence of changes that occur in the vaginal and vulvar microbiota during puberty. The study enrolled 31 healthy, premenarcheal girls between the ages of 10 and 12 years and collected vaginal and vulvar swabs quarterly for up to 3 years. Bacterial composition was characterized by Roche 454 pyrosequencing and classification of regions V1 to V3 of 16S rRNA genes. Contrary to expectations, lactic acid bacteria, primarily Lactobacillus spp., were dominant in the microbiota of most girls well before the onset of menarche in the early to middle stages of puberty.Gardnerella vaginaliswas detected at appreciable levels in approximately one-third of subjects, a notable finding considering that this organism is commonly associated with bacterial vaginosis in adults. Vulvar microbiota closely resembled vaginal microbiota but often exhibited additional taxa typically associated with skin microbiota. Our findings suggest that the vaginal microbiota of girls begin to resemble those of adults well before the onset of menarche.IMPORTANCEThis study addresses longitudinal changes in vaginal and vulvar microbial communities prior to and immediately following menarche. The research is significant because microbial ecology of the vagina is an integral aspect of health, including resistance to infections. The physiologic changes of puberty and initiation of cyclic menstruation are likely to have profound effects on vaginal microbiota, but almost nothing is known about changes that normally occur during this time. Our understanding has been especially hampered by the lack of thorough characterization of microbial communities using techniques that do not rely on the cultivation of fastidious bacteria, as well as a dearth of studies on girls in the early to middle stages of puberty. This study improves our understanding of the normal development of vaginal microbiota during puberty and onset of menarche and may better inform clinical approaches to vulvovaginal care of adolescent girls.

scholarly journals Novel Microbial Assemblages Dominate Weathered Sulfide-Bearing Rock from Copper-Nickel Deposits in the Duluth Complex, Minnesota, USA

2017 ◽  
Vol 83 (16) ◽  
Author(s):  
Daniel S. Jones ◽  
Kim A. Lapakko ◽  
Zachary J. Wenz ◽  
Michael C. Olson ◽  
Elizabeth W. Roepke ◽  
...  
Keyword(s):  
Microbial Communities ◽  
Microbial Ecology ◽  
Mine Waste ◽  
Experimental Treatment ◽  
Sulfide Mineral ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Content Type ◽  
Duluth Complex ◽  
Copper Nickel

ABSTRACT The Duluth Complex in northeastern Minnesota hosts economically significant deposits of copper, nickel, and platinum group elements (PGEs). The primary sulfide mineralogy of these deposits includes the minerals pyrrhotite, chalcopyrite, pentlandite, and cubanite, and weathering experiments show that most sulfide-bearing rock from the Duluth Complex generates moderately acidic leachate (pH 4 to 6). Microorganisms are important catalysts for metal sulfide oxidation and could influence the quality of water from mines in the Duluth Complex. Nevertheless, compared with that of extremely acidic environments, much less is known about the microbial ecology of moderately acidic sulfide-bearing mine waste, and so existing information may have little relevance to those microorganisms catalyzing oxidation reactions in the Duluth Complex. Here, we characterized the microbial communities in decade-long weathering experiments (kinetic tests) conducted on crushed rock and tailings from the Duluth Complex. Analyses of 16S rRNA genes and transcripts showed that differences among microbial communities correspond to pH, rock type, and experimental treatment. Moreover, microbial communities from the weathered Duluth Complex rock were dominated by taxa that are not typically associated with acidic mine waste. The most abundant operational taxonomic units (OTUs) were from the genera Meiothermus and Sulfuriferula, as well as from diverse clades of uncultivated Chloroflexi, Acidobacteria, and Betaproteobacteria. Specific taxa, including putative sulfur-oxidizing Sulfuriferula spp., appeared to be primarily associated with Duluth Complex rock, but not pyrite-bearing rocks subjected to the same experimental treatment. We discuss the implications of these results for the microbial ecology of moderately acidic mine waste with low sulfide content, as well as for kinetic testing of mine waste. IMPORTANCE Economic sulfide mineral deposits in the Duluth Complex may represent the largest undeveloped source of copper and nickel on Earth. Microorganisms are important catalysts for sulfide mineral oxidation, and research on extreme acidophiles has improved our ability to manage and remediate mine wastes. We found that the microbial assemblages associated with weathered rock from the Duluth Complex are dominated by organisms not widely associated with mine waste or mining-impacted environments, and we describe geochemical and experimental influences on community composition. This report will be a useful foundation for understanding the microbial biogeochemistry of moderately acidic mine waste from these and similar deposits.

scholarly journals Identification of a Stable Hydrogen-Driven Microbiome in a Highly Radioactive Storage Facility on the Sellafield Site

2020 ◽  
Vol 11 ◽  
Author(s):  
Sharon Ruiz-Lopez ◽  
Lynn Foster ◽  
Chris Boothman ◽  
Nick Cole ◽  
Katherine Morris ◽  
...  
Keyword(s):  
16S Rrna ◽  
Microbial Communities ◽  
Nuclear Fuel ◽  
Spent Nuclear Fuel ◽  
Quantitative Polymerase Chain Reaction ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Rrna Gene ◽  
Bacterial Cells ◽  
Spent Fuel

The use of nuclear power has been a significant part of the United Kingdom’s energy portfolio with the Sellafield site being used for power production and more recently reprocessing and decommissioning of spent nuclear fuel activities. Before being reprocessed, spent nuclear fuel is stored in water ponds with significant levels of background radioactivity and in high alkalinity (to minimize fuel corrosion). Despite these challenging conditions, the presence of microbial communities has been detected. To gain further insight into the microbial communities present in extreme environments, an indoor, hyper-alkaline, oligotrophic, and radioactive spent fuel storage pond (INP) located on the Sellafield site was analyzed. Water samples were collected from sample points within the INP complex, and also the purge water feeding tank (FT) that supplies water to the pond, and were screened for the presence of the 16S and 18S rRNA genes to inform sequencing requirements over a period of 30 months. Only 16S rRNA genes were successfully amplified for sequencing, suggesting that the microbial communities in the INP were dominated by prokaryotes. Quantitative Polymerase Chain Reaction (qPCR) analysis targeting 16S rRNA genes suggested that bacterial cells in the order of 104–106 mL–1 were present in the samples, with loadings rising with time. Next generation Illumina MiSeq sequencing was performed to identify the dominant microorganisms at eight sampling times. The 16S rRNA gene sequence analysis suggested that 70% and 91% from of the OTUs samples, from the FT and INP respectively, belonged to the phylum Proteobacteria, mainly from the alpha and beta subclasses. The remaining OTUs were assigned primarily to the phyla Acidobacteria, Bacteroidetes, and, Cyanobacteria. Overall the most abundant genera identified were Hydrogenophaga, Curvibacter, Porphyrobacter, Rhodoferax, Polaromonas, Sediminibacterium, Roseococcus, and Sphingomonas. The presence of organisms most closely related to Hydrogenophaga species in the INP areas, suggests the metabolism of hydrogen as an energy source, most likely linked to hydrolysis of water caused by the stored fuel. Isolation of axenic cultures using a range of minimal and rich media was also attempted, but only relatively minor components (from the phylum Bacteroidetes) of the pond water communities were obtained, emphasizing the importance of DNA-based, not culture-dependent techniques, for assessing the microbiome of nuclear facilities.

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