Comparative genome sequence analysis of several species in the genus Tepidimonas and the description of a novel species Tepidimonas charontis sp. nov.

We performed high-quality genome sequencing of eight strains of the species of the genus Tepidimonas and examined the genomes of closely related strains from the databases to understand why Tepidimonas taiwanensis is the only strain of this genus that utilizes glucose and fructose for growth. We found that the assimilation of these hexoses by T. taiwanensis was due to the presence of two transporters that are absent in all other genomes of strains of members of the genus Tepidimonas examined. Some strains lack genes coding for glucokinase, but the Embden-Meyerhof-Parnas pathway appears to be otherwise complete. The pentose phosphate pathway has a complete set of genes, but genes of the Entner-Doudoroff pathway were not identified in the genomes of any of the strains examined. Genome analysis using average nucleotide identity (ANIb), digital DNA-DNA hybridization (dDDH), average amino acid identity (AAI) and phylogenetic analysis of 400 conserved genes was performed to assess the taxonomic classification of the organisms. Two isolates of the genus Tepidimonas from the hot spring at São Pedro do Sul, Portugal, designated SPSP-6T and SPSPC-18 were also examined in this study. These organisms are mixotrophic, have an optimum growth temperature of about 50 ºC, utilize several organic acids and amino acids for growth but do not grow on sugars. Distinctive phenotypic, 16S rRNA gene sequence and genomic characteristics of strains SPSP-6T and SPSPC-18 lead us to propose a novel species based on strain SPSP-6T for which we recommend the name Tepidimonas charontis sp. nov. (=CECT 9683T=LMG 30884T).

Doxorubicin persistently rewires cardiac circadian homeostasis in mice.

Circadian rhythms disruption can be the cause of chronic diseases. External cues, including therapeutic drugs, have been shown to modulate peripheral-circadian clocks. Since anthracycline cardiotoxicity is associated with loss of mitochondrial function and metabolic remodeling, we investigated whether the energetic failure induced by sub-chronic doxorubicin (DOX) treatment in juvenile mice was associated with persistent disruption of circadian regulators. Juvenile C57BL/6J male mice were subjected to a sub-chronic DOX treatment (4 weekly injections of 5 mg/kg DOX) and several cardiac parameters, as well as circadian-gene expression and acetylation patterns, were analyzed after 6 weeks of recovery time. Complementary experiments were performed with Mouse Embryonic Fibroblasts (MEFs) and Human Embryonic Kidney 293 cells. DOX-treated juvenile mice showed cardiotoxicity markers and persistent alterations of transcriptional- and signaling cardiac circadian homeostasis. The results showed a delayed influence of DOX on gene expression, accompanied by changes in SIRT1-mediated cyclic deacetylation. The mechanism behind DOX interference with the circadian clock was further studied in vitro, in which were observed alterations of circadian-gene expression and increased BMAL1 SIRT1-mediated deacetylation. In conclusion, DOX treatment in juvenile mice resulted in disruption of oscillatory molecular mechanisms including gene expression and acetylation profiles.

Transfer of Meiothermus chliarophilus (Tenreiro et al.1995) Nobre et al. 1996, Meiothermus roseus Ming et al. 2016, Meiothermus terrae Yu et al. 2014 and Meiothermus timidus Pires et al. 2005, to Calidithermus gen. nov., as Calidithermus chliarophilus comb. nov., Calidithermus roseus comb. nov., Calidithermus terrae comb. nov. and Calidithermus timidus comb. nov., respectively, and emended description of the genus Meiothermus.

Chemotaxonomic parameters, phylogenetic analysis of the 16S rRNA gene, phylogenetic analysis of 90 housekeeping genes and 855 core genes, amino acid identity (AAI), average nucleotide identity (ANI) and genomic characteristics were used to examine the 13 species of the genus Meiothermuswith validly published names to reclassify this genus. The results indicate that the species of the genus Meiothermus can be divided into three lineages on the basis of the results of the phylogenetic analysis, AAI, the guanine+cytosine (G+C) mole ratio, the ability to synthesize the red-pigmented carotenoid canthaxanthin and the colony colour, as well as other genomic characteristics. The results presented in this study circumscribe the genus Meiothermus to the species Meithermus ruber, Meiothermus cateniformans, Meiothermus taiwanensis, Meiothermus cerbereus, Meiothermus hypogaeus, Meiothermus luteus, Meiothermus rufus and Meiothermus granaticius, for which it is necessary to emend the genus Meiothermus. The species Meiothermus silvanus, which clearly represents a separate genus level lineage was not reclassified in this study for lack of any distinctive phenotypic or genotypic characteristics. The results of this study led us to reclassify the species Meiothermus chliarophilus, Meiothermus timidus, Meiothermus roseus and Meiothermus terrae as species of a novel genus for which we propose the epithet Calidithermus gen. nov.

Lysobacter silvestris sp. nov., isolated from alpine forest soil, and reclassification of Luteimonas tolerans as Lysobacter tolerans comb. nov.

A Gram-stain-negative, rod-shaped, motile, catalase-positive and cytochrome c oxidase-positive bacterial strain, designated AM20-91T, was isolated from alpine forest soil. Phylogenetic analysis based on 16S rRNA gene sequencing showed that strain AM20-91T was related to the genus Lysobacter and had highest 16S rRNA gene sequence similarities to the type strains of Lysobacter novalis THG-PC7T (97.8 %), Luteimonas tolerans UM1T (97.7 %) and Lysobacter ximonensis XM415T (97.0 %). The strain contained ubiquinone 8 as the predominant respiratory quinone; its polar lipid profile contained phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol and two unidentified aminophospholipids. The major cellular fatty acids (>10 %) were iso-C15 : 0, iso-C11 : 0 3-OH and iso-C11 : 0. The DNA G+C content was 63.35 % (draft genome sequence). The combined results of phylogenetic, phenotypic, DNA-DNA relatedness and chemotaxonomic analyses demonstrated that strain AM20-91T represents a novel species of the genus Lysobacter, for which the name Lysobacter silvestris sp. nov. is proposed. The type strain is AM20-91T (=DSM 104734T=LMG 30011). In this study, it is also proposed that Luteimonas tolerans be reclassified as member of the genus Lysobacter.

Raineya orbicola gen. nov., sp. nov. a slightly thermophilic bacterium of the phylum Bacteroidetes and the description of Raineyaceae fam. nov.

An isolate, designated SPSPC-11T, with an optimum growth temperature of about 50 °C and an optimum pH for growth between 7.5 and 8.0, was recovered from a hot spring in central Portugal. Based on phylogenetic analysis of its 16S rRNA sequence, the new organism is most closely related to the species of the genus Thermonema but with a pairwise sequence similarity of <85 %. The isolate was orange-pigmented, formed non-motile long filaments and rod-shaped cells that stain Gram-negative. The organism was strictly aerobic, oxidase-positive and catalase-positive. The major fatty acids were iso-C15:0, iso-C15 : 0 2-OH and iso-C17 : 0 3-OH. The major polar lipids were one aminophospholipid, two aminolipids and three unidentified lipids. Menaquinone 7 was the major respiratory quinone. The DNA G+C content of strain SPSPC-11T was 37.6 mol% (draft genome sequence). The high quality draft genome sequence corroborated many of the phenotypic characteristics of strain SPSPC-11T. Based on genotypic, phylogenetic, physiological and biochemical characterization we describe a new species of a novel genus represented by strain SPSPC-11T (=CECT 9012T=LMG 29233T) for which we propose the name Raineya orbicola gen. nov., sp. nov. We also describe the family Raineyaceae to accommodate this new genus and species.

Solimicrobium silvestre gen. nov., sp. nov., isolated from alpine forest soil.

A Gram-stain-negative, rod-shaped, motile, catalase and cytochrome c oxidase-positive bacterial strain, designated S20-91T, was isolated from alpine forest soil. Growth occurred within a temperature range of 0-25 °C. Yeast extract was required for growth. Phylogenetic analysis based on 16S rRNA gene sequencing showed that strain S20-91T was related to the genus Herminiimonas and had the highest 16S rRNA gene sequence similarity to Herminiimonas arsenicoxydans ULPAs1T (96.5 %). The strain contained ubiquinone 8 as the predominant respiratory quinone and phosphatidylethanolamine, phosphatidylglycerol and diphosphatidylglycerol as the major polar lipids. The major cellular fatty acids (>10 %) were C16 : 1ω7c (55.3 %) and C16 : 0 (25.6 %). The genomic DNA G+C content was 47.6 mol%. Combined data of genomic, phylogenetic, phenotypic and chemotaxonomic analyses demonstrated that strain S20-91T represents a novel genus and species, for which the name Solimicrobium silvestre gen. nov., sp. nov. is proposed. The type strain is S20-91T (=DSM 104733T=LMG 30010).

Metagenomic Signatures of Microbial Communities in Deep-Sea Hydrothermal Sediments of Azores Vent Fields.

The organisms inhabiting the deep-seafloor are known to play a crucial role in global biogeochemical cycles. Chemolithoautotrophic prokaryotes, which produce biomass from single carbon molecules, constitute the primary source of nutrition for the higher organisms, being critical for the sustainability of food webs and overall life in the deep-sea hydrothermal ecosystems. The present study investigates the metabolic profiles of chemolithoautotrophs inhabiting the sediments of Menez Gwen and Rainbow deep-sea vent fields, in the Mid-Atlantic Ridge. Differences in the microbial community structure might be reflecting the distinct depth, geology, and distance from vent of the studied sediments. A metagenomic sequencing approach was conducted to characterize the microbiome of the deep-sea hydrothermal sediments and the relevant metabolic pathways used by microbes. Both Menez Gwen and Rainbow metagenomes contained a significant number of genes involved in carbon fixation, revealing the largely autotrophic communities thriving in both sites. Carbon fixation at Menez Gwen site was predicted to occur mainly via the reductive tricarboxylic acid cycle, likely reflecting the dominance of sulfur-oxidizing Epsilonproteobacteria at this site, while different autotrophic pathways were identified at Rainbow site, in particular the Calvin-Benson-Bassham cycle. Chemolithotrophy appeared to be primarily driven by the oxidation of reduced sulfur compounds, whether through the SOX-dependent pathway at Menez Gwen site or through reverse sulfate reduction at Rainbow site. Other energy-yielding processes, such as methane, nitrite, or ammonia oxidation, were also detected but presumably contributing less to chemolithoautotrophy. This work furthers our knowledge of the microbial ecology of deep-sea hydrothermal sediments and represents an important repository of novel genes with potential biotechnological interest.

Priming of a DNA metabarcoding approach for species identification and inventory in marine macrobenthic communities.

In marine and estuarine benthic communities, the inventory and estimation of species richness are often hampered by the need for broad taxonomic expertise across several phyla. The use of DNA metabarcoding has emerged as a powerful tool for the fast assessment of species composition in a diversity of ecological communities. Here, we tested the amplification success of five primer sets targeting different COI-5P regions by 454 pyrosequencing to maximize the recovery of two simulated macrobenthic communities containing 21 species (SimCom1 and SimCom 2). Species identification was first performed against a compiled reference library of macrobenthic species. Reads with similarity results to reference sequences between 70% and 97% were then submitted to GenBank and BOLD to attempt the identification of concealed species in the bulk sample. The combination of at least three primer sets was able to recover more species than any primer set alone, achieving 85% of represented species in SimCom1 and 76% in SimCom2. Our approach was successful to detect low-frequency specimens, as well as concealed species, in the bulk sample, indicating the potential for the application of this approach on marine bioassessment and inventory, including the detection of "hidden" biodiversity that would hardly be possible based on morphology only.

Sediment Microbial Diversity of Three Deep-Sea Hydrothermal Vents Southwest of the Azores.

Menez Gwen, Lucky Strike and Rainbow are the three most visited and well-known deep-sea hydrothermal vent fields in the Azores region, located in the Mid-Atlantic Ridge. Their distinct geological and ecological features allow them to support a diversity of vent communities, which are largely dependent on Bacteria and Archaea capable of anaerobic or microaerophilic metabolism. These communities play important ecological roles through chemoautotrophy, feeding and in establishing symbiotic associations. However, the occurrence and distribution of these microbes remain poorly understood, especially in deep-sea sediments. In this study, we provide for the first time a comparative survey of the sediment-associated microbial communities from these three neighbouring vent fields. Sediment samples collected in the Menez Gwen, Lucky Strike and Rainbow vent fields showed significant differences in trace-metal concentrations and associated microbiomes. The taxonomic profiles of bacterial, archaeal and eukaryotic representatives were assessed by rRNA gene-tag pyrosequencing, identified anaerobic methanogens and microaerobic Epsilonproteobacteria, particularly at the Menez Gwen site, suggesting sediment communities potentially enriched in sub-seafloor microbes rather than from pelagic microbial taxa. Cosmopolitan OTUs were also detected mostly at Lucky Strike and Rainbow sites and affiliated with the bacterial clades JTB255, Sh765B-TzT-29, Rhodospirillaceae and OCS155 marine group and with the archaeal Marine Group I. Some variations in the community composition along the sediment depth were revealed. Elemental contents and hydrothermal influence are suggested as being reflected in the composition of the microbial assemblages in the sediments of the three vent fields. Altogether, these findings represent valuable information for the understanding of the microbial distribution and potential ecological roles in deep-sea hydrothermal fields.

New splicing mutation in the choline kinase beta (CHKB) gene causing a muscular dystrophy detected by whole-exome sequencing.

Muscular dystrophies (MDs) are a group of hereditary muscle disorders that include two particularly heterogeneous subgroups: limb-girdle MD and congenital MD, linked to 52 different genes (seven common to both subgroups). Massive parallel sequencing technology may avoid the usual stepwise gene-by-gene analysis. We report the whole-exome sequencing (WES) analysis of a patient with childhood-onset progressive MD, also presenting mental retardation and dilated cardiomyopathy. Conventional sequencing had excluded eight candidate genes. WES of the trio (patient and parents) was performed using the ion proton sequencing system. Data analysis resorted to filtering steps using the GEMINI software revealed a novel silent variant in the choline kinase beta (CHKB) gene. Inspection of sequence alignments ultimately identified the causal variant (CHKB:c.1031+3G>C). This splice site mutation was confirmed using Sanger sequencing and its effect was further evaluated with gene expression analysis. On reassessment of the muscle biopsy, typical abnormal mitochondrial oxidative changes were observed. Mutations in CHKB have been shown to cause phosphatidylcholine deficiency in myofibers, causing a rare form of CMD (only 21 patients reported). Notwithstanding interpretative difficulties that need to be overcome before the integration of WES in the diagnostic workflow, this work corroborates its utility in solving cases from highly heterogeneous groups of diseases, in which conventional diagnostic approaches fail to provide a definitive diagnosis.

Synthesis, antiangiogenesis evaluation and molecular docking studies of 1-aryl-3-[(thieno[3,2-b]pyridin-7-ylthio)phenyl]ureas: Discovery of a new substitution pattern for type II VEGFR-2 Tyr kinase inhibitors.

The synthesis and biological evaluation of novel 1-aryl-3-[2-, 3- or 4-(thieno[3,2-b]pyridin-7-ylthio)phenyl]ureas 3, 4 and 5 as VEGFR-2 tyrosine kinase inhibitors, are reported. The 1-aryl-3-[3-(thieno[3,2-b]pyridin-7-ylthio)phenyl]ureas 4a-4h, with the arylurea in the meta position to the thioether, showed the lowest IC50 values in enzymatic assays (10-206 nM), the most potent compounds 4d-4h (IC50 10-28 nM) bearing hydrophobic groups (Me, F, CF3 and Cl) in the terminal phenyl ring. A convincing rationalization was achieved for the highest potent compounds 4 as type II VEGFR-2 inhibitors, based on the simultaneous presence of: (1) the thioether linker and (2) the arylurea moiety in the meta position. For compounds 4, significant inhibition of Human Umbilical Vein Endothelial Cells (HUVECs) proliferation (BrdU assay), migration (wound-healing assay) and tube formation were observed at low concentrations. These compounds have also shown to increase apoptosis using the TUNEL assay. Immunostaining for total and phosphorylated (active) VEGFR-2 was performed by Western blotting. The phosphorylation of the receptor was significantly inhibited at 1.0 and 2.5 µM for the most promising compounds. Altogether, these findings point to an antiangiogenic effect in HUVECs.

Docking studies in target proteins involved in antibacterial action mechanisms: extending the knowledge on standard antibiotics to antimicrobial mushroom compounds.

In the present work, the knowledge on target proteins of standard antibiotics was extended to antimicrobial mushroom compounds. Docking studies were performed for 34 compounds in order to evaluate their affinity to bacterial proteins that are known targets for some antibiotics with different mechanism of action: inhibitors of cell wall synthesis, inhibitors of protein synthesis, inhibitors of nucleic acids synthesis and antimetabolites. After validation of the molecular docking approach, virtual screening of all the compounds was performed against penicillin binding protein 1a (PBP1a), alanine racemase (Alr), d-alanyl-d-alanine synthetase (Ddl), isoleucyl-tRNA sinthetase (IARS), DNA gyrase subunit B, topoisomerase IV (TopoIV), dihydropteroate synthetase (DHPS) and dihydrofolate reductase (DHFR) using AutoDock4. Overall, it seems that for the selected mushroom compounds (namely, enokipodins, ganomycins and austrocortiluteins) the main mechanism of the action is the inhibition of cell wall synthesis, being Alr and Ddl probable protein targets.

Virtual screening of low molecular weight mushrooms compounds as potential Mdm2 inhibitors.

In some human cancer cases, the activity of p53 is inhibited by over-expressed Mdm2. The Mdm2 acts as an ubiquitin ligase, resulting in p53 ubiquitination and subsequent p53 proteasomal degradation. The disruption of the Mdm2-p53 interaction using small-molecule inhibitors is recognized as a promising strategy for anti-cancer drug design. Mushrooms are an important source of powerful compounds with anti-tumour properties. In this study, the first virtual screening of low molecular weight compounds present in mushroom is presented as potential Mdm2 inhibitors. A re-docking and cross-docking method was used to validate the virtual screening protocol. The steroids: ganoderic acids X (K(i) = 16nM), Y (K(i) = 22nM) and F (K(i) = 69nM); 5,6-epoxy-24(R)-methylcholesta-7,22-dien-3ß-ol (K(i) = 74nM) and polyporenic acid C (K(i) = 59nM) stand out as the top ranked potential inhibitors of Mdm2. The docking pose of the most promising compounds were carefully analysed and the information provided shows several interesting starting points for further development of Mdm2 inhibitors.

High-quality draft genome sequence of Gaiella occulta isolated from a 150 meter deep mineral water borehole and comparison with the genome sequences of other deep-branching lineages of the phylum Actinobacteria.

Gaiella occulta strain F2-233T (=CECT 7815 = LMG 26412), isolated from a 150 meter deep mineral water aquifer, was deemed a candidate for high-quality draft genome sequencing because of the rare environment from which it was isolated. The draft genome sequence (QQZY00000000) of strain F2-233T is composed of approximately 3 Mb, predicted 3,119 protein-coding genes of which 2,545 were assigned putative functions. Genome analysis was done by comparison with the other deep-branching Actinobacteria neighbors Rubrobacter radiotolerans, Solirubrobacter soli and Thermoleophilum album. The genes for the tricarboxylic acid cycle, gluconeogenesis and pentose phosphate pathway, were identified in G. occulta, R. radiotolerans, S. soli and T. album genomes. Genes of the Embden-Meyerhof-Parnas pathway and nitrate reduction were identified in G. occulta, R. radiotolerans and S. soli, but not in the T. album genome. Alkane degradation is precluded by genome analysis in G. occulta. Genes involved in myo-inositol metabolism were found in both S. soli and G. occulta genomes. A Calvin-Benson-Bassham (CBB) cycle with a type I RuBisCO was identified in G. occulta genome, as well. However, experimental growth under several conditions was negative and CO2 fixation could not be proven in G. occulta.

Draft genome sequence of Bacillus amyloliquefaciens subsp. plantarum strain Fito_F321, an endophyte microorganism from Vitis vinifera with biocontrol potential.

Bacillus amyloliquefaciens subsp. plantarum strain Fito_F321 is a naturally occurring strain in vineyard, with the ability to colonise grapevine and which unveils a naturally antagonistic potential against phytopathogens of grapevine, including those responsible for the Botryosphaeria dieback, a GTD disease. Herein we report the draft genome sequence of B. amyloliquefaciens subsp. plantarum Fito_F321, isolated from the leaf of Vitis vinifera cv. Merlot at Bairrada appellation (Cantanhede, Portugal). The genome size is 3,856,229 bp, with a GC content of 46.54% that contains 3697 protein-coding genes, 86 tRNA coding genes and 5 rRNA genes. The draft genome of strain Fito_F321 allowed to predict a set of bioactive compounds as bacillaene, difficidin, macrolactin, surfactin and fengycin that due to their antimicrobial activity are hypothesized to be of utmost importance for biocontrol of grapevine diseases.

Metatranscriptomics profile of the gill microbial community during Bathymodiolus azoricus aquarium acclimatization at atmospheric pressure.

BACKGROUND: The deep-sea mussels Bathymodiolus azoricus (Bivalvia: Mytilidae) are the dominant macrofauna subsisting at the hydrothermal vents site Menez Gwen in the Mid-Atlantic Ridge (MAR). Their adaptive success in such challenging environments is largely due to their gill symbiotic association with chemosynthetic bacteria. We examined the response of vent mussels as they adapt to sea-level environmental conditions, through an assessment of the relative abundance of host-symbiont related RNA transcripts to better understand how the gill microbiome may drive host-symbiont interactions in vent mussels during hypothetical venting inactivity. RESULTS: The metatranscriptome of B. azoricus was sequenced from gill tissues sampled at different time-points during a five-week acclimatization experiment, using Next-Generation-Sequencing. After Illumina sequencing, a total of 181,985,262 paired-end reads of 150 bp were generated with an average of 16,544,115 read per sample. Metatranscriptome analysis confirmed that experimental acclimatization in aquaria accounted for global gill transcript variation. Additionally, the analysis of 16S and 18S rRNA sequences data allowed for a comprehensive characterization of host-symbiont interactions, which included the gradual loss of gill endosymbionts and signaling pathways, associated with stress responses and energy metabolism, under experimental acclimatization. Dominant active transcripts were assigned to the following KEGG categories: "Ribosome", "Oxidative phosphorylation" and "Chaperones and folding catalysts" suggesting specific metabolic responses to physiological adaptations in aquarium environment. CONCLUSIONS: Gill metagenomics analyses highlighted microbial diversity shifts and a clear pattern of varying mRNA transcript abundancies and expression during acclimatization to aquarium conditions which indicate change in bacterial community activity. This approach holds potential for the discovery of new host-symbiont associations, evidencing new functional transcripts and a clearer picture of methane metabolism during loss of endosymbionts. Towards the end of acclimatization, we observed trends in three major functional subsystems, as evidenced by an increment of transcripts related to genetic information processes; the decrease of chaperone and folding catalysts and oxidative phosphorylation transcripts; but no change in transcripts of gluconeogenesis and co-factors-vitamins.

Wild Roman chamomile extracts and phenolic compounds: enzymatic assays and molecular modelling studies with VEGFR-2 tyrosine kinase.

Angiogenesis is a process by which new blood vessels are formed from the pre-existing vasculature, and it is a key process that leads to tumour development. Some studies have recognized phenolic compounds as chemopreventive agents; flavonoids, in particular, seem to suppress the growth of tumor cells modifying the cell cycle. Herein, the antiangiogenic activity of Roman chamomile (Chamaemelum nobile L.) extracts (methanolic extract and infusion) and the main phenolic compounds present (apigenin, apigenin-7-O-glucoside, caffeic acid, chlorogenic acid, luteolin, and luteolin-7-O-glucoside) was evaluated through enzymatic assays using the tyrosine kinase intracellular domain of the Vascular Endothelium Growth Factor Receptor-2 (VEGFR-2), which is a transmembrane receptor expressed fundamentally in endothelial cells involved in angiogenesis, and molecular modelling studies. The methanolic extract showed a lower IC50 value (concentration that provided 50% of VEGFR-2 inhibition) than the infusion, 269 and 301 µg mL(-1), respectively. Regarding phenolic compounds, luteolin and apigenin showed the highest capacity to inhibit the phosphorylation of VEGFR-2, leading us to believe that these compounds are involved in the activity revealed by the methanolic extract.

Microbial diversity in deep-sea sediments from the Menez Gwen hydrothermal vent system of the Mid-Atlantic Ridge.

Deep-sea hydrothermal sediments are known to support remarkably diverse microbial consortia. Cultureindependent sequence-based technologies have extensively been used to disclose the associated microbial diversity as most of the microorganisms inhabiting these ecosystems remain uncultured. Here we provide the first description of the microbial community diversity found on sediments from Menez Gwen vent system. We compared hydrothermally influenced sediments, retrieved from an active vent chimney at 812 m depth, with non-hydrothermally influenced sediments, from a 1400 m depth bathyal plain. Considering the enriched methane and sulfur composition of Menez Gwen vent fluids, and the sediment physicochemical properties in each sampled area, we hypothesized that the site-associated microbes would be different. To address this question, taxonomic profiles of bacterial, archaeal and micro-eukaryotic representatives were studied by rRNA gene tag pyrosequencing. Communities were shown to be significantly different and segregated by sediment geographical area. Specific mesophilic, thermophilic and hyperthermophilic archaeal (e.g., Archaeoglobus, ANME-1) and bacterial (e.g., Caldithrix, Thermodesulfobacteria) taxa were highly abundant near the vent chimney. In contrast, bathyal-associated members affiliated to more ubiquitous phylogroups from deep-ocean sediments (e.g., Thaumarchaeota MGI, Gamma- and Alphaproteobacteria). This study provides a broader picture of the biological diversity and microbial biogeography, and represents a preliminary approach to the microbial ecology associated with the deep-sea sediments from the Menez Gwen hydrothermal vent field.