Increased intestinal permeability and lipopolysaccharide contribute to swainsonine-induced systemic inflammation.

Long-term consumption of swainsonine could be poisonous to livestock, including facilitating apoptosis by impairing lysosomal function and inhibiting autophagic degradation, leading to liver inflammation and even death in livestock. However, the mechanism by swainsonine induced systemic inflammatory responses remained unclear, especially the effects of swainsonine on intestinal permeability, lipopolysaccharide (LPS) level and oxidative stress response were unknown. In this study, swainsonine increased intestinal permeability as evidenced by the significant down-regulation of colonic goblet cells, Akkermansia muciniphila and intestinal tight junction protein Occludin, Claudin 1 and ZO-1, and the significant up-regulation of mRNA expression level of the intestinal permeability indicator protein tyrosine phosphatase receptor type H (Ptprh) in the ileum of mice. Simultaneously, the elevated LPS biosynthetic genes in intestinal microbiota and increased intestinal permeability facilitated more bacterial endotoxin LPS to enter the blood. High concentration of free-form LPS induced high levels of proinflammatory cytokines and oxidative stress response, thereby causing the systemic inflammation. These findings provided a new perspective on swainsonine-induced systemic inflammation, suggesting that intestinal permeability and free-form LPS level may be the potential trigger factors.

Emerging role of the crosstalk between gut microbiota and liver metabolome of subterranean herbivores in response to toxic plants.

Plant secondary metabolites (PSMs) are a defense mechanism against herbivores, which in turn use detoxification metabolism to process ingested and absorbed PSMs. The feeding environment can cause changes in liver metabolism patterns and the gut microbiota. Here, we compared gut microbiota and liver metabolome to investigate the response mechanism of plateau zokors (Eospalax baileyi) to toxic plant Stellera chamaejasme (SC) in non-SC and SC grassland (-SCG and +SCG). Our results indicated that exposure to SC in the -SCG population increased liver inflammatory markers including prostaglandin (PG) in the Arachidonic acid pathway, while exposure to SC in the +SCG population exhibited a significant downregulation of PGs. Secondary bile acids were significantly downregulated in +SCG plateau zokors after SC treatment. Of note, the microbial taxa Veillonella in the -SCG group was significantly correlated with liver inflammation markers, while Clostridium innocum in the +SCG group had a significant positive correlation with secondary bile acids. The increase in bile acids and PGs can lead to liver inflammatory reactions, suggesting that +SCG plateau zokors may mitigate the toxicity of SC plants by reducing liver inflammatory markers including PGs and secondary bile acids, thereby avoiding liver damage. This provides new insight into mechanisms of toxicity by PSMs and counter-mechanisms for toxin tolerance by herbivores.

Removal of antibiotic thiamphenicol by bacterium Aeromonas hydrophila HS01.

Thiamphenicol (TAP) is an amphenicol antibiotic, which has a broad-spectrum inhibitory effect on both gram-positive and gram-negative bacteria. Since it is widely used in animals and aquaculture, its residues in environment may bring potential risk for human health and ecosystems. While TAP can be removed through conventional physical or chemical methods, its bioremediation using microorganisms is less studied. Here, we report the removal of TAP by a bacterial strain, Aeromonas hydrophila HS01, which can remove more than 90.0% of TAP in a living cell-dependent manner. Our results indicated that its removal efficiency can be greatly affected by the growth condition. Proteomics studies revealed a number of differentially expressed proteins of HS01 in the presence of TAP, which may play critical roles in the transportation and degradation of TAP. All these results indicate bacterial strain A. hydrophila HS01 is a new microbial resource for efficiently removing TAP, and may shed new insights in developing bioremediation approaches for TAP pollution.

Environment dependent microbial co-occurrences across a cyanobacterial bloom in a freshwater lake.

Microbial taxon-taxon co-occurrences may directly or indirectly reflect the potential relationships between the members within a microbial community. However, to what extent and the specificity by which these co-occurrences are influenced by environmental factors remains unclear. In this report, we evaluated how the dynamics of microbial taxon-taxon co-occurrence is associated with the changes of environmental factors in Nan Lake at Wuhan city, China with a Modified Liquid Association method. We were able to detect more than 1000 taxon-taxon co-occurrences highly correlated with one or more environmental factors across a phytoplankton bloom using 16S rRNA gene amplicon community profiles. These co-occurrences, referred to as environment dependent co-occurrences (ED_co-occurrences), delineate a unique network in which a taxon-taxon pair exhibits specific, and potentially dynamic correlations with an environmental parameter, while the individual relative abundance of each may not. Microcystis involved ED_co-occurrences are in important topological positions in the network, suggesting relationships between the bloom dominant species and other taxa could play a role in the interplay of microbial community and environment across various bloom stages. Our results may broaden our understanding of the response of a microbial community to the environment, particularly at the level of microbe-microbe associations.

Metabolomics safety assessments of microcystin exposure via drinking water in rats.

Drinking water exposure to microcystin-leucine-arginine (MC-LR), the most widely occurring cyanotoxins, poses a highly potential risk for human health. However, the health risk of MC-LR exposure at current guideline value in drinking water has not yet entirely evaluated. In the current study, we used 1H NMR-based metabolomics combined with targeted metabolic profiling by GC/LC-MS to explore the toxic effects of MC-LR exposure at environmentally relevant concentrations via drinking water in rats. The results revealed that multiple biological consequences of MC-LR exposure on host metabolism in rats. Both relatively low and high doses of MC-LR used here induced hepatic lipogenesis and inflammation. While only relatively high dose MC-LR (10 µg/L) in drinking water caused more metabolic disorders including inhibition of gluconeogenesis and promotion of ß-oxidation of fatty acid. Although the dose of 1.0 µg/L MC-LR is extremely low for rats, alterations of metabolic profiles were unexpectedly found in rat liver and serum, alarming potential health risk of MC-LR at the WHO guideline level.

Metabolic response of Agrobacterium tumefaciens 5A to arsenite.

Wide-spread abundance in soil and water, coupled with high toxicity have put arsenic at the top of the list of environmental contaminants. Early studies demonstrated that both concentration and the valence state of inorganic arsenic (arsenite, As(III) vs. arsenate As(V)) can be modulated by microbes. Using genetics, transcriptomic and proteomic techniques, microbe-arsenic detoxification, respiratory As(V) reduction and As(III) oxidation have since been examined. The effect of arsenic exposure on whole-cell intracellular microbial metabolism, however, has not been extensively studied. We combined LC-MS and 1 H NMR to quantify metabolic changes in Agrobacterium tumefaciens (strain 5A) upon exposure to sub-lethal concentrations of As(III). Metabolomics analysis reveals global differences in metabolite concentrations between control and As(III) exposure groups, with significant perturbations to intermediates shuttling into and cycling within the TCA cycle. These data are most consistent with the disruption of two key TCA cycle enzymes, pyruvate dehydrogenase and α-ketoglutarate dehydrogenase. Glycolysis also appeared altered following As(III) stress, with carbon accumulating as complex saccharides. These observations suggest that an important consequence of As(III) contamination in nature will be to alter microbial carbon metabolism at the microbial community level and thus has the potential to foundationally impact all biogeochemical cycles in the environment.

Involvement of the Acr3 and DctA anti-porters in arsenite oxidation in Agrobacterium tumefaciens 5A.

Microbial arsenite (AsIII) oxidation forms a critical piece of the arsenic cycle in nature, though our understanding of how and why microorganisms oxidize AsIII remains rudimentary. Our model organism Agrobacterium tumefaciens 5A contains two distinct ars operons (ars1 and ars2) that are similar in their coding region content. The ars1 operon is located nearby the aio operon that is essential for AsIII oxidation. The AsIII/H(+) anti-porters encoded by acr3-1 and acr3-2 are required for maximal AsIII and antimonite (SbIII) resistance, but acr3-1 (negatively regulated by ArsR-1) appears more active in this regard and also required for AsIII oxidation and expression of aioBA. A malate-phosphate anti-porter DctA is regulated by RpoN and AsIII, and is required for normal growth with malate as a sole carbon source. Qualitatively, a ΔdctA mutant was normal for AsIII oxidation and AsIII/SbIII resistance at metalloid concentrations inhibitory to the Δacr3-1 mutant; however, aioBA induction kinetics was significantly phase-shift delayed. Acr3 involvement in AsIII/SbIII resistance is reasonably well understood, but the role of Acr3 and DctA anti-porters in AsIII oxidation and its regulation is unexpected, and suggests that controlled AsIII trafficking across the cytoplasmic membrane is important to a process understood to occur in the periplasm.

Combining microbiome and pseudotargeted metabolomics revealed the alleviative mechanism of Cupriavidus sp. WS2 on the cadmium toxicity in Vicia unijuga A.Br.

Cadmium (Cd) pollution is one of the most severe toxic metals pollution in grassland. Vicia unijuga (V. unijuga) A.Br. planted nearby the grassland farming are facing the risk of high Cd contamination. Here, we investigated the beneficial effects of a highly Cd tolerant rhizosphere bacterium, Cupriavidus sp. WS2, on Cd contaminated V. unijuga. Through plot experiments, we set up four groups of treatments: the control group (without WS2 or Cd), the Cd group (with only Cd addition), the WS2 group (with only WS2 addition), and the WS2/Cd group (with WS2 and Cd addition), and analyzed the changes in physiological indicators, rhizosphere microorganisms, and stem and leaf metabolites of V. unijuga. Results of physiological indicators indicated that Cupriavidus sp. WS2 had strong absorption and accumulation capacity of Cd, exogenous addition of strain WS2 remarkably decreased the Cd concentrations, and increased the plant heights, the biomass, the total protein concentrations, the chlorophyll contents and the photosynthetic rate in stems and leaves of V. unijuga under Cd stress. Cd treatment increased the abundance of Cd tolerant bacterial genera in rhizosphere microbiome, but these genera were down-regulated in the WS2/Cd group. Pseudotargeted metabolomic results showed that six common differential metabolites associated with antioxidant stress were increased after co-culture with WS2. In addition, WS2 activated the antioxidant system including glutathione (GSH) and catalase (CAT), reduced the contents of oxidative stress markers including malondialdehyde (MDA) and hydrogen peroxide (H2O2) in V. unijuga under Cd stress. Taken together, this study revealed that Cupriavidus sp.WS2 alleviated the toxicity of V. unijuga under Cd exposure by activating the antioxidant system, increasing the antioxidant metabolites, and reducing the oxidative stress markers.

Multiomics Reveals Mechanisms of Alternaria oxytropis Inhibiting Pathogenic Fungi in Oxytropis ochrocephala.

Endophytic fungi can benefit the host plant and increase the plant resistance. Now, there is no in-depth study of how Alternaria oxytropis (A. oxytropis) is enhancing the ability of inhibiting pathogenic fungi in Oxytropis ochrocephala (O. ochrocephala). In this study, the fungal community and metabolites associated with endophyte-infected (EI) and endophyte-free (EF) O. ochrocephala were compared by multiomics. The fungal community indicated that there was more A. oxytropis, less phylum Ascomycota, and less genera Leptosphaeria, Colletotrichum, and Comoclathris in the EI group. As metabolic biomarkers, the levels of swainsonine and apigenin-7-O-glucoside-4-O-rutinoside were significantly increased in the EI group. Through in vitro validation experiments, swainsonine and apigenin-7-O-glucoside-4-O-rutinoside can dramatically suppress the growth of pathogenic fungi Leptosphaeria sclerotioides and Colletotrichum americae-borealis by increasing the level of oxidative stress. This work suggested that O. ochrocephala containing A. oxytropis could increase the resistance to fungal diseases by markedly enhancing the content of metabolites inhibiting pathogenic fungi.

Impaired Indole Acetic Acid and Reduced Indole-Producing Bacteria Contribute to Swainsonine-Induced Liver Inflammation.

Liver inflammation could be elicited by swainsonine in livestock, affecting the development of agriculture and animal husbandry. Our previous study showed an important role of bile acids (BAs) in swainsonine-induced hepatic inflammation. However, its pathogenesis, particularly the roles of a comprehensive profile of liver and serum metabolites and microbial-derived indole metabolites, has not been clarified. This study aimed to demonstrate the mechanisms linking the indole-producing bacteria and indole metabolites to swainsonine-induced hepatic inflammation by combining Targeted 500 metabolomics and quantitative analysis of indole metabolites. Swainsonine significantly disturbed the liver and serum metabolomes in mice. Genus Akkermansia alleviating inflammation and genus Lactobacillus producing indole metabolites were significantly declined. Indole acetic acid (IAA) was the only reduced aryl hydrocarbon receptor (AHR) ligand in this study. Analogously, some bacteria causing liver damage markedly increased. These findings suggested that indole-producing bacteria and indole metabolites may be potential triggers of swainsonine-induced hepatic inflammation.

Identification and verification of the role of key metabolites and metabolic pathways on ASFV replication.

African swine fever virus (ASFV) infection usually causes viremia within a few days. However, the metabolic changes in pig serum after ASFV infection remain unclear. In this study, serum samples collected from ASFV-infected pigs at different times were analyzed using pseudotargeted metabolomics method. Metabolomic analysis revealed the dopaminergic synapse pathway has the highest rich factor in both ASFV5 and ASFV10 groups. By disrupting the dopamine synaptic pathway, dopamine receptor antagonists inhibited ASFV replication and L-dopa promoted ASFV replication. In addition, guanosine, one of the top20 changed metabolites in both ASFV5 and ASFV10 groups suppressed the replication of ASFV. Taken together, this study revealed the changed serum metabolite profiles of ASFV-infected pigs at various times after infection and verified the effect of the changed metabolites and metabolic pathways on ASFV replication. These findings may contribute to understanding the pathogenic mechanisms of ASFV and the development of target drugs to control ASF.

Sphingobium cupriresistens sp. nov., a copper-resistant bacterium isolated from copper mine soil, and emended description of the genus Sphingobium.

A gram-negative, aerobic, copper-resistant bacterium, designated strain CU4(T), was isolated from copper mine soil in Daye, China. Phylogenetic analysis based on 16S rRNA gene sequences showed highest similarity to Sphingobium rhizovicinum CC-FH12-1(T) (98.4 %), followed by Sphingobium francense Sp+(T) (97.2 %), Sphingobium japonicum UT26(T) (97.1 %), Sphingobium abikonense NBRC 16140(T) (97.0 %), Sphingobium xenophagum DSM 6383(T) (96.9 %) and Sphingobium yanoikuyae DSM 7462(T) (95.5 %). The major fatty acids (>5 %) were summed feature 7 (C(18 : 1)ω7c, C(18 : 1)ω9t and/or C(18 : 1)ω12t), summed feature 4 (C(16 : 1)ω7c and/or iso-C(15 : 0) 2-OH), C(16 : 0) and C(14 : 0) 2-OH, and the predominant quinone was ubiquinone Q-10. Spermidine was the major polyamine component. The major polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, sphingoglycolipid, phosphatidyldimethylethanolamine and phosphatidylcholine. The genomic DNA G+C content of strain CU4(T) was 64.9 mol%. Comparison of DNA-DNA hybridization, phenotypic and chemotaxonomic characteristics between strain CU4(T) and phylogenetically related strains revealed that the new isolate represents a novel species of the genus Sphingobium, for which the name Sphingobium cupriresistens sp. nov. is proposed. The type strain is CU4(T) ( = KCTC 23865(T) = CCTCC AB 2011146(T)). An emended description of the genus Sphingobium is also proposed.

Swainsonine Induces Liver Inflammation in Mice via Disturbance of Gut Microbiota and Bile Acid Metabolism.

Swainsonine induced liver inflammation in livestock; however, the underlying mechanisms, especially the role of bile acids (BAs), in the pathogenesis remained elusive. Here, our results showed that swainsonine induced hepatic inflammation via changing BA metabolism and gut microbiota in mice. Swainsonine significantly upregulated the levels of deoxycholic acid (DCA) and taurine-ß-muricholic acid (T-ß-MCA) in the serum and liver of mice due to the markedly increased genus Clostridium and the decreased genus Lactobacillus in the gut. As antagonists of the farnesoid X receptor (FXR), elevated DCA and T-ß-MCA inhibited hepatic Fxr gene expression and thus suppressed FXR-SHP signaling and activated hepatic Cyp7a1 gene expression, which induced a significant upregulation of the total BA level in serum, contributing to liver inflammation. These findings offer new insights into the underlying mechanisms in which swainsonine induced liver inflammation in mice via the gut-liver axis and suggest that gut microbiota and its metabolite BAs may be underlying triggering factors.

Kynurenic acid mediates bacteria-algae consortium in resisting environmental cadmium toxicity.

Cadmium (Cd2+) is a toxic heavy metal in the environment, posing severe damage to animal health and drinking water safety. The bacteria-algae consortium remediates environmental Cd2+ pollution by secreting chelating reagents, but the molecular mechanisms remain elusive. Here, we showed that Cellulosimicrobium sp. SH8 isolated from a Cd2+-polluted lake could interact with Synechocystis sp. PCC6803, a model species of cyanobacteria, in strengthening Cd2+ toxicity resistance, while SH8 or PCC6803 alone barely immobilized Cd2+. In addition, the SH8-PCC6803 consortium, but not SH8 alone, could grow in a carbon-free medium, suggesting that autotrophic PCC6803 enabled the growth of heterotrophic SH8. Totally, 12 metabolites were significantly changed when SH8 was added to PCC6803 culture in the presence of Cd2+ (PCC6803/Cd2+). Among them, kynurenic acid was the only metabolite that precipitated Cd2+. Remarkably, adding kynurenic acid increased the growth of PCC6803/Cd2+ by 14.1 times. Consistently, the expressions of kynA, kynB, and kynT genes, known to be essential for kynurenic acid synthesis, were considerably increased when SH8 was added to PCC6803/Cd2+. Collectively, kynurenic acid secreted by SH8 mitigates Cd2+ toxicity for algae, and algae provide organic carbon for the growth of SH8, unveiling a critical link that mediates beneficial bacteria-algae interaction to resist Cd2+.

Dietary Isoquercetin Reduces Hepatic Cholesterol and Triglyceride in NAFLD Mice by Modulating Bile Acid Metabolism via Intestinal FXR-FGF15 Signaling.

Isoquercetin, a monosaccharide flavonoid, was recently reported to have significant amelioration effects on high-fat diet (HFD)-induced nonalcoholic fatty liver disease (NAFLD) of mice. However, the underlying mechanism of hepatic cholesterol and triglyceride improvement in mice fed HFD by isoquercetin remains unclear. Here, a combination of 16S rRNA gene sequencing, targeted quantification of bile acids (BAs), and biological assays was employed to investigate the beneficial effects of isoquercetin on NAFLD in mice. The results showed that dietary isoquercetin markedly modulated the BAs profiling in various samples such as liver, serum, intestine, and feces. We found that dietary isoquercetin promoted BA biosynthesis via the activation of alternative pathways and inhibition of intestinal FXR-Fgf15 signaling, thus reducing 13.2% hepatic cholesterol and 16.05% triglyceride in NAFLD mice. Dietary isoquercetin also regulated a series of receptors mediating correspondent processes of BA transportation, reabsorption, and excretion. Of particular note, dietary isoquercetin significantly modulated cross-talk between BAs and specific gut bacteria of NAFLD mice. These findings revealed that long-term intake of isoquercetin plays beneficial roles in the prevention or intervention of fatty liver disease.

Altitude-dependent metabolite biomarkers reveal the mechanism of plateau pika adaptation to high altitudes.

The harsh environment in the Tibetan plateau, the highest place in the world, poses thermoregulatory challenges and hypoxic stress to animals. The impacts of plateau environment on animal physiology and reproduction include external factors such as strong ultraviolet radiation and low temperature, and internal factors such as animal metabolites and gut microbiota. However, it remains unclear how plateau pika adapt to high altitudes through the combination of serum metabolites and gut microbiota. To this end, we captured 24 wild plateau pikas at the altitudes of 3400, 3600, or 3800 m a.s.l. in a Tibetan alpine grassland. Using the machine learning algorithms (random forest), we identified five biomarkers of serum metabolites indicative of the altitudes, that is, dihydrotestosterone, homo-l-arginine, alpha-ketoglutaric-acid, serotonin, and threonine, which were related to body weight, reproduction, and energy metabolism of pika. Those metabolic biomarkers were positively correlated with Lachnospiraceae_ Agathobacter, Ruminococcaceae, or Prevotellaceae_Prevotella, suggesting the close relationship between metabolites and gut microbiota. By identifying the metabolic biomarkers and gut microbiota analysis, we reveal the mechanisms of adaptation to high altitudes in plateau pika.

Plasma metabolic signatures for intracranial aneurysm and its rupture identified by pseudotargeted metabolomics.

BACKGROUND AND AIMS: The vital metabolic signatures for IA risk stratification and its potential biological underpinnings remain elusive. Our study aimed to develop an early diagnosis model and rupture classification model by analyzing plasma metabolic profiles of IA patients. MATERIALS AND METHODS: Plasma samples from a cohort of 105 participants, including 75 IA patients in unruptured and ruptured status (UIA, RIA) and 30 control participants were collected for comprehensive metabolic evaluation using ultra-high-performance liquid chromatography-mass spectrometry-based pseudotargeted metabolomics method. Furthermore, an integrated machine learning strategy based on LASSO, random forest and logistic regression were used for feature selection and model construction. RESULTS: The metabolic profiling disturbed significantly in UIA and RIA patients. Notably, adenosine content was significantly downregulated in UIA, and various glycine-conjugated secondary bile acids were decreased in RIA patients. Enriched KEGG pathways included glutathione metabolism and bile acid metabolism. Two sets of biomarker panels were defined to discriminate IA and its rupture with the area under receiver operating characteristic curve of 0.843 and 0.929 on the validation sets, respectively. CONCLUSIONS: The present study could contribute to a better understanding of IA etiopathogenesis and facilitate discovery of new therapeutic targets. The metabolite panels may serve as potential non-invasive diagnostic and risk stratification tool for IA.

Lysobacter arseniciresistens sp. nov., an arsenite-resistant bacterium isolated from iron-mined soil.

A Gram-negative, aerobic, motile, rod-shaped, arsenite [As(III)]-resistant bacterium, designated strain ZS79(T), was isolated from subsurface soil of an iron mine in China. Phylogenetic analyses based on 16S rRNA gene sequences revealed that strain ZS79(T) clustered closely with strains of five Lysobacter species, with 96.9, 96.1, 96.0, 95.8 and 95.3% sequence similarities to Lysobacter concretionis Ko07(T), L. daejeonensis GH1-9(T), L. defluvii IMMIB APB-9(T), L. spongiicola KMM 329(T) and L. ruishenii CTN-1(T), respectively. The major cellular fatty acids were iso-C(15:0) (28.6%), iso-C(17:1)ω9c (19.9%), iso-C(16:0) (13.6%), iso-C(11:0) (12.6%) and iso-C(11:0) 3-OH (12.4%). The genomic DNA G+C content was 70.7 mol% and the major respiratory quinone was Q-8. The major polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol and an unknown phospholipid. On the basis of morphological and physiological/biochemical characteristics, phylogenetic position and chemotaxonomic data, this strain is considered to represent a novel species of the genus Lysobacter, for which the name Lysobacter arseniciresistens sp. nov. is proposed; the type strain is ZS79(T) (=CGMCC 1.10752(T)=KCTC 23365(T)).

Skermanella stibiiresistens sp. nov., a highly antimony-resistant bacterium isolated from coal-mining soil, and emended description of the genus Skermanella.

A Gram-negative, aerobic, motile, rod-shaped, antimony-resistant bacterium, designated strain SB22(T), was isolated from soil of Jixi coal mine, China. The major cellular fatty acids (>5 %) were C(18:1)ω7c (63.5 %), summed feature 2 (C(14:0) 3-OH and/or iso-C(16:1) I, 10.8 %) and C(16:0) (9.9 %). The major polar lipids were diphosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol and an unknown aminolipid. The genomic DNA G+C content was 69.6 mol% and Q-10 was the major respiratory quinone. Phylogenetic analyses based on 16S rRNA gene sequences indicated that strain SB22(T) was most closely related to Skermanella aerolata 5416T-32(T) (97.3 %), Skermanella parooensis ACM 2042(T) (95.8 %) and Skermanella xinjiangensis 10-1-101(T) (92.9 %). The DNA-DNA hybridization value between strain SB22(T) and S. aerolata KACC 11604(T) ( = 5416T-32(T)) was 43.3 %. On the basis of phenotypic, chemotaxonomic and phylogenetic characteristics of strain SB22(T) and related species, it is considered that the isolate represents a novel species of the genus Skermanella, for which the name Skermanella stibiiresistens sp. nov. is proposed. The type strain is SB22(T) ( = CGMCC 1.10751(T) = KCTC 23364(T)). An emended description of the genus Skermanella is provided.

Arenimonas metalli sp. nov., isolated from an iron mine.

A Gram-staining-negative, aerobic, rod-shaped bacterium (CF5-1(T)) was isolated from Hongshan Iron Mine, Daye City, Hubei province, China. The major cellular fatty acids (>10%) were iso-C(16:0), iso-C(15:0), C(16:1)ω7c alcohol and iso-C(17:1)ω9c. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine. The major respiratory quinone was Q-8. The genomic DNA G+C content was 70.5 mol%. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain CF5-1(T) was most closely related to Arenimonas malthae (95.3% gene sequence similarity), Arenimonas oryziterrae (94.7%), Arenimonas donghaensis (94.6%) and Arenimonas composti (94.5%). A taxonomic study using a polyphasic approach showed that strain CF5-1(T) represents a novel species of the genus Arenimonas, for which the name Arenimonas metalli sp. nov. is proposed. The type strain is CF5-1(T) ( = CGMCC 1.10787(T) = KCTC 23460(T) = CCTCC AB 2010449(T)).