ABSTRACT
A novel sulphate-reducing, Gram-stain-negative, anaerobic strain, isolate XJ01T, recovered from production fluid at the LiaoHe oilfield, PR China, was the subject of a polyphasic study. The isolate together with Desulfovibrio oxamicus NCIMB 9442T and Desulfovibrio termitidis DSM 5308T formed a distinct, well-supported clade in the Desulfovibrionaceae 16S rRNA gene tree. The taxonomic status of the clade was underscored by complementary phenotypic data. The three isolates comprising the clade formed distinct phyletic branches and were distinguished using a combination of physiological features and by low average nucleotide identity and digital DNA-DNA hybridization values. Consequently, it is proposed that isolate XJ01T represents a novel genus and species for which the name Cupidesulfovibrio liaohensis gen. nov., sp. nov. is proposed with the type strain XJ01T (=CGMCC 1.5227T=DSM 107637T). It is also proposed that D. oxamicus and D. termitidis be reclassified as Cupidesulfovibrio oxamicus comb. nov. and Cupidesulfovibrio termitidis comb. nov., respectively.
Subject(s)
Desulfovibrionaceae/classification , Oil and Gas Fields/microbiology , Phylogeny , Bacterial Typing Techniques , Base Composition , China , DNA, Bacterial/genetics , Desulfovibrio/classification , Desulfovibrionaceae/isolation & purification , Fatty Acids/chemistry , Nucleic Acid Hybridization , Oxidation-Reduction , RNA, Ribosomal, 16S/genetics , Sequence Analysis, DNA , Sulfates/metabolism , Sulfur-Reducing Bacteria/classification , Sulfur-Reducing Bacteria/isolation & purificationABSTRACT
BACKGROUND: Gut microbiota plays an important role in many metabolic diseases such as diabetes and atherosclerosis. Apolipoprotein E (apoE) knock-out (KO) mice are frequently used for the study of hyperlipidemia and atherosclerosis. However, it is unknown whether apoE KO mice have altered gut microbiota when challenged with a Western diet. METHODS: In the current study, we assessed the gut microbiota profiling of apoE KO mice and compared with wild-type mice fed either a normal chow or Western diet for 12 weeks using 16S pyrosequencing. RESULTS: On a western diet, the gut microbiota diversity was significantly decreased in apoE KO mice compared with wild type (WT) mice. Firmicutes and Erysipelotrichaceae were significantly increased in WT mice but Erysipelotrichaceae was unchanged in apoE KO mice on a Western diet. The weighted UniFrac principal coordinate analysis exhibited clear separation between WT and apoE KO mice on the first vector (58.6%) with significant changes of two dominant phyla (Bacteroidetes and Firmicutes) and seven dominant families (Porphyromonadaceae, Lachnospiraceae, Ruminococcaceae, Desulfovibrionaceae, Helicobacteraceae, Erysipelotrichaceae and Veillonellaceae). Lachnospiraceae was significantly enriched in apoE KO mice on a Western diet. In addition, Lachnospiraceae and Ruminococcaceae were positively correlated with relative atherosclerosis lesion size in apoE KO. CONCLUSIONS: Collectively, our study showed that there are marked changes in the gut microbiota of apoE KO mice, particularly challenged with a Western diet and these alterations may be possibly associated with atherosclerosis.
Subject(s)
Apolipoproteins E/deficiency , Atherosclerosis/microbiology , Diet, Western/adverse effects , Gastrointestinal Microbiome/genetics , Hyperlipidemias/microbiology , Animals , Apolipoproteins E/genetics , Atherosclerosis/etiology , Atherosclerosis/genetics , Atherosclerosis/pathology , Bacteroidetes/classification , Bacteroidetes/genetics , Bacteroidetes/isolation & purification , DNA, Ribosomal/genetics , Desulfovibrionaceae/classification , Desulfovibrionaceae/genetics , Desulfovibrionaceae/isolation & purification , Disease Models, Animal , Firmicutes/classification , Firmicutes/genetics , Firmicutes/isolation & purification , Helicobacteraceae/classification , Helicobacteraceae/genetics , Helicobacteraceae/isolation & purification , Hyperlipidemias/etiology , Hyperlipidemias/genetics , Hyperlipidemias/pathology , Lipids/blood , Male , Mice , Mice, Inbred C57BL , Mice, Knockout, ApoE , Porphyromonas/classification , Porphyromonas/genetics , Porphyromonas/isolation & purification , RNA, Ribosomal, 16S/genetics , Ruminococcus/classification , Ruminococcus/genetics , Ruminococcus/isolation & purification , Sequence Analysis, DNA , Severity of Illness Index , Veillonellaceae/classification , Veillonellaceae/genetics , Veillonellaceae/isolation & purificationABSTRACT
Mercury methylation converts inorganic mercury into the toxic methylmercury, and the consequences of this transformation are worrisome for human health and the environment. This process is performed by anaerobic microorganisms, such as several strains related to Pseudodesulfovibrio and Desulfovibrio genera. In order to provide new insights into the molecular mechanisms of mercury methylation, we performed a comparative genomic analysis on mercury methylators and non-methylators from (Pseudo)Desulfovibrio strains. Our results showed that (Pseudo)Desulfovibrio species are phylogenetically and metabolically distant and consequently, these genera should be divided into various genera. Strains able to perform methylation are affiliated with one branch of the phylogenetic tree, but, except for hgcA and hgcB genes, no other specific genetic markers were found among methylating strains. hgcA and hgcB genes can be found adjacent or separated, but proximity between those genes does not promote higher mercury methylation. In addition, close examination of the non-methylator Pseudodesulfovibrio piezophilus C1TLV30 strain, showed a syntenic structure that suggests a recombination event and may have led to hgcB depletion. The genomic analyses identify also arsR gene coding for a putative regulator upstream hgcA. Both genes are cotranscribed suggesting a role of ArsR in hgcA expression and probably a role in mercury methylation.