Cloning grass carp (Ctenopharyngodon idella) ccdc3 and its expression affected by nutrition state, insulin, and glucagon.

As an adipokine, coiled-coil domain-containing 3 (CCDC3) plays multiple physiological roles in fatty liver, lipid metabolism, and abdominal obesity. Grass carp was selected as the experimental animal in this study to investigate the roles of Ccdc3 in teleosts. Results showed that the open reading frame (ORF) of cloned ccdc3 was 831 bp and encoded 276 amino acids. Three N-glycosylation sites and a predicted coiled-coil domain motif were located in the identified Ccdc3. Moreover, a nuclear localization signal (NLS) was contained in the coiled-coil domain motif of the identified Ccdc3. The results on tissue distribution revealed that ccdc3 was highly detected in grass carp fat and brain tissue. In the oral glucose tolerance test (OGTT), the expression of ccdc3 increased remarkably in the brain, hypothalamus, and visceral fat in the glucose treatment group. In the fasting and refeeding experiment, the ccdc3 expression levels were remarkably reduced in the brain, hypothalamus, and visceral fat after 14 days of fasting. In the refeeding group, the ccdc3 expression levels were considerably elevated compared with those in the fasting group. In the induced overfeeding experiment, the ccdc3 expression increased remarkably in the hepatopancreas, brain, and visceral fat tissues. The ccdc3 expression in the primary hepatocytes was remarkably increased with glucose, oleic acid, and insulin treatment. However, ccdc3 expression was markedly decreased with glucagon treatment. In conclusion, these results indicate that Ccdc3 is involved in regulating glucose and lipid metabolism of teleosts.

Dietary Bacillus velezensis R-71003 and sodium gluconate improve antioxidant capacity, immune response and resistance against Aeromonas hydrophila in common carp.

This study aimed to evaluate the effects of dietary supplementation with Bacillus velezensis R-71003 combined with sodium gluconate on antioxidant capacity, immune response and resistance against Aeromonas hydrophila in common carp. In addition, the biocontrol potential of the secondary metabolites of B. velezensis R-71003 was also evaluated to analyze the possible mechanism of B. velezensis R-71003 against A. hydrophila. The results indicated that the antibacterial crude extract of B. velezensis R-71003 can destroy the cell wall of A. hydrophila. Moreover, the results showed that dietary B. velezensis R-71003 could promote antioxidant capacity, which significantly increased the activities of CAT and SOD and decreased the content of MDA. Additionally, B. velezensis R-71003 supplementation significantly enhanced the immunity of common carp, as measured by the mRNA expression levels of cytokine-related genes (TNF-α, TGF-ß, IL-1ß and IL-10). In addition, dietary B. velezensis R-71003 exhibited an upregulation of IL-10 and a downregulation of IL-1ß, coupled with higher survival rates when challenged with A. hydrophila compared to the positive group. Furthermore, compared to prechallenge, the mRNA expression levels of TLR-4, MyD88, IRAK1, TRAF6, TRIF and NF-κB in the head kidney of common carp were significantly increased after challenge. The fish fed the B. velezensis R-71003 diet showed lower expression of TLR-4, MyD88, IRAK1, TRAF6, TRIF and NF-κB after the challenge than those fed the control diet. Thus, this study revealed that B. velezensis R-71003 can improve the resistance of common carp to pathogenic bacteria by destroying bacterial cell walls and improving fish immunity by activating the TLR4 signaling pathway. Importantly, this study indicated that sodium gluconate has a positive effect on B. velezensis R-71003 in enhancing the anti-infection ability of common carp. The results of this study will lay the foundation for the application of B. velezensis R-71003 in combination with sodium gluconate as an alternative to antibiotics in aquaculture.

Molecular Characterization of Grass Carp GIPR and Effect of Nutrition States, Insulin, and Glucagon on Its Expression.

GIP plays an important regulatory role in glucose and lipid metabolism. As the specific receptor, GIPR is involved in this physiological process. To assess the roles of GIPR in teleost, the GIPR gene was cloned from grass carp. The ORF of cloned GIPR gene was 1560 bp, encoding 519 amino acids. The grass carp GIPR was the G-protein-coupled receptor which contains seven predicted transmembrane domains. In addition, two predicted glycosylation sites were contained in the grass carp GIPR. The grass carp GIPR expression is in multiple tissues and is highly expressed in the kidney, brain regions, and visceral fat tissue. In the OGTT experiment, the GIPR expression is markedly decreased in the kidney, visceral fat, and brain by treatment with glucose for 1 and 3 h. In the fast and refeeding experiment, the GIPR expression in the kidney and visceral fat tissue was significantly induced in the fast groups. In addition, the GIPR expression levels were markedly decreased in the refeeding groups. In the present study, the visceral fat accumulation of grass carp was induced by overfed. The GIPR expression was significantly decreased in the brain, kidney, and visceral fat tissue of overfed grass carp. In primary hepatocytes, the GIPR expression was promoted by treatment with oleic acid and insulin. The GIPR mRNA levels were significantly reduced by treatment with glucose and glucagon in the grass carp primary hepatocytes. To our knowledge, this is the first time the biological role of GIPR is unveiled in teleost.

Chronic developmental exposure to low-dose ([C8mim][PF6]) induces neurotoxicity and behavioural abnormalities in rats.

Ionic liquids (ILs) are widely used for their physical and chemical properties. Toxicological assessments of ILs could help to avoid their threat to human health, but these are rarely reported, and no assessments of IL neurotoxicity in mammals have been performed. Here, we aimed to evaluate the neurotoxicity of chronic 1-octyl-3-methylimidazolium hexafluorophosphate ([C8mim][PF6]) (0, 1 mg/kg) exposure during development on rats. Our results indicated that chronic exposure to low-dose ([C8mim][PF6]) induces behavioural abnormalities, including cognitive deficits, social communication disorders, and sensory gating function impairment. Moreover, rats subjected to chronic ([C8mim][PF6]) exposure showed hypofunction of glutamatergic excitatory synapses, including increased expression of NMDA receptor subunits, increased density and immaturity of dendritic spines, and increased expression of PSD95. Additionally, ([C8mim][PF6]) exposure resulted in hippocampal-specific inflammatory activation, indicated by increased levels of proinflammatory factors, elevated nuclear localisation of NF-κB, and activation of microglia and astrocytes. In conclusion, chronic exposure to low-dose ([C8mim][PF6]) induced neurotoxicity, including damage to glutamatergic excitatory synapses and inflammatory activation, which may illuminate the associated behavioural abnormalities. The results presented here may be helpful for the safe use of ILs in the future.

Bacillus coagulans SCC-19 maintains intestinal health in cadmium-exposed common carp (Cyprinus carpio L.) by strengthening the gut barriers, relieving oxidative stress and modulating the intestinal microflora.

Heavy metal cadmium (Cd) pollution is a serious problem affecting the sustainable development of aquaculture and the safety of aquatic foods. Research about the use of probiotics to attenuate toxic damage caused by Cd2+ in aquatic animals has received widespread attention. Bacillus coagulans (B. coagulans), a kind of probiotics commonly used in aquaculture, has been shown to adsorb Cd2+ both in vivo and vitro. Here, we aimed to determine the effects of B. coagulans on Cd2+ bioaccumulation, gut barrier function, oxidative stress and gut microbiota in common carp following Cd2+ exposure. The fish were exposure to Cd2+ at 0 and 0.5 mg/L and/or fed a B. coagulans-containing diet at 107, 108 and 109 CFU/g for 8 weeks. The results indicated that B. coagulans can maintain gut barrier function in Cd2+-exposed fish by reducing Cd2+ bioaccumulation, increasing the mRNA levels of tight junction protein genes (occludin, claudin-2 and zonula occludens-1), and decreasing the levels of diamine oxidase and D-lactic acid. In addition, B. coagulans could relieve oxidative stress in Cd2+-exposed fish by restoring the activities of glutathione peroxidase, catalase and superoxide dismutase. Moreover, Cd2+ exposure decreased the intestinal microbiota diversity and changed the intestinal microbiota compositions in common carp. However, supplementation with B. coagulans could reverse the altered intestinal microbiota diversity and composition after Cd2+ exposure, decrease the abundance of some pathogens (Shewanella and Vibrio), and increase the abundance of probiotics (Bacillus and Lactobacillus). These results indicate that B. coagulans may serve as a potential antidote for alleviating Cd2+ toxicity.

Impacts of an azo food dye tartrazine uptake on intestinal barrier, oxidative stress, inflammatory response and intestinal microbiome in crucian carp (Carassius auratus).

Food dyes, or color additives, are often added into foods, cosmetics and beverages during processing to improve the sensory attributes of the final products. However, the toxicity of tartrazine (TZ), one of the most common azo-dyes, is still unclear, and needs to be ascertained by further study. Hence, in the present study, we aimed to evaluate the effects of TZ consumption on health by using a teleost, crucian carp (Carassius auratus) as the experimental fish. TZ consumption (1.4, 5.5 and 10 mg/kg bwt/day) could cause severe histopathological and cellular alterations in intestine and liver. The height of intestinal villus, thickness of intestinal muscle, and microvilli density were also affected. With the increasing of TZ concentrations, the activities of antioxidant enzymes (CAT, SOD and GSH-Px), exhibited a decreasing trend, while the contents of MDA elevated. Upregulations of pro-inflammatory cytokines (il6 and tnfα), anti-inflammatory cytokines (il8, and il10) and other immune related genes (complement component 3 (c3), lysozymes (lyz), ß-defensin 3 (defb3)), were observed after TZ uptake. In addition, TZ consumption also affected the community structure of the microbiota in the intestine of crucian carp. The amount of some probiotic bacteria (Roseomonas, Rhodococcus and Bacillus) and the bacteria (Bacteroides and Clostridium), producing short chain fatty acids, were significantly reduced, and some pathogenetic microorganisms (e.g. Bdellovibrio and Shewanella) were significantly increased after TZ uptake. In summary, the data in the present study indicate that TZ consumption, even at a low concentration, may lead to adverse effects on fish health. Therefore, in aquaculture, it is necessary to be informed about the hazardous effects of TZ, and more attentions should be focused on using natural substitutes.

Effects of an exopolysaccharide from Lactococcus lactis Z-2 on innate immune response, antioxidant activity, and disease resistance against Aeromonas hydrophila in Cyprinus carpio L.

Microbial exopolysaccharides (EPS) from Lactococcus have been found to have an important role in the probiotic activity of this bacterium; however, the immunomodulatory and antioxidant activities have not been fully explored in aquaculture. In the present study, we investigated EPS-2 from Lactococcus lactis Z-2, isolated from healthy common carp, for its immunomodulatory and antioxidant effects and disease resistance against Aeromonas hydrophila in Cyprinus carpio L. We found that the molecular weight of EPS-2 was 18.65 KDa. The monosaccharide composition of this polymer was rhamnose, xylose, mannose, glucose, and galactose at a molar percentage of 13.3%, 14.1%, 18.5%, 27.4%, and 26.7%, respectively. EPS-2 treatment could modulate the immune responses in vitro and in vivo. In vitro tests showed that EPS-2 could significantly enhance the proliferation and phagocytosis activities (P < 0.05) as well as induce the production of nitic oxide (NO), pro-inflammatory cytokines (TNF-α, IL-1ß, IL-6), and anti-inflammatory cytokines (IL-10, TGF-ß) (P < 0.05) in head kidney cells. When the fish were gavaged with three different concentrations of EPS-2 (250, 500, 1000 µg/mL) for 7 days and infected with A. hydrophila, different expression patterns of the NO, cytokines, lysozyme (LZM), and alkaline phosphatase (AKP) in the serum and of antioxidants (T-AOC, SOD, CAT, GSH, GSH-Px and MDA) in hepatopancreas were observed. Before infection with A. hydrophila, EPS-2 supplementation significantly up-regulated the NO production, protein levels of pro-inflammatory cytokines (TNF-α, IL-1ß, IL-6), LZM and AKP activities, and levels of antioxidant molecules compared to those in the negative (G1) group (P < 0.05), whereas levels of NO and pro-inflammatory cytokines and LZM and AKP activities were significantly lower than those in the positive (G2) group after infection (P < 0.05). However, whether infected or not, the expression levels of anti-inflammatory cytokines (IL-10, TGF-ß) were significantly increased in the EPS-2 treatment groups (P < 0.05). These results indicate that EPS-2 has immunomodulatory and antioxidant effects on common carp, both in vitro and/or in vivo, and can be applied as a common carp feed supplement to enhance fish immunity and disease resistance against A. hydrophila.

Impact of chronic exposure to the ionic liquid ([C8mim][PF6]) on intestinal physical barrier, immunological barrier and gut microbiota in common carp (Cyprinus carpio L.).

Ionic liquids (ILs) are commonly known as "green" solvents and have been widely used in various fields. However, the ecotoxicity of ILs in aquatic environment has received considerable attention from scientific researchers. This study investigated the toxic effects of different concentrations of 1-octyl-3-methylimidazolium hexafluorophosphate ([C8mim][PF6]) (0, 1.35, 2.70 and 5.40 mg/L) on intestinal physical barrier, immunological barrier, and intestinal microbiome in common carp on days 30 and 60. The results showed that ([C8mim][PF6]) exposure could reduce the intestinal villus height, decrease the mRNA expression of tight junction genes (occludin, claudin-2 and zonula occludens-1), and increase the levels of D-lactic and diamine oxidase, and reduce acid phosphatase and lysozyme activities, complement 3 and 4 contents, and anti-inflammatory cytokine TGF-ß protein level, while increase pro-inflammatory cytokines TNF-α and IL-1ß protein levels in common carp. Moreover, ([C8mim][PF6]) exposure was also found to significantly reduce gut microbial diversity and alter microbial community structure in common carp. Collectively, our study highlighted that exposure to ([C8mim][PF6]) could disrupt intestinal physical barrier, impair immunological barrier and alter intestinal microbiome in common carp, suggesting that ILs exert a negative effect on fish intestinal health status and may pose serious health risks in fish. The results of this study may be helpful to illuminate the toxicity mechanisms of the ILs on fish.

Effects of dechlorane plus on intestinal barrier function and intestinal microbiota of Cyprinus carpio L.

Dechlorane Plus (DP) is a typical polychlorinated flame retardant that has been emerged in chemical products. Due to its accumulation and amplification effect, the toxicity of DP has become a widespread environmental safety issue. However, whether DP can affect the intestinal tract of teleost fish remains largely unclear. To understand its effects on the intestinal barrier, morphological characteristics and intestinal microbiome of common carp, different concentrations (30, 60 and 120 µg/L) of DP were exposed to common carps for 4 weeks. The results indicated that DP evidently shortened the intestinal folds and damaged the intestinal epithelium layer. In addition, the mRNA expression levels of occludin, claudin-2 and zonula occludens-1 (ZO-1) were significantly decreased with increasing DP concentrations. Furthermore, the relative abundance of some microbiota species were also changed significantly. Our study first demonstrated that DP could cause damage to the intestinal epithelium and destroy the intestinal barrier and increase the relative abundance of pathogenic bacteria, thereby increasing the probability of contact between intestinal epithelium and pathogenic bacteria, which in turn lead to an increased susceptibility to various diseases and poor health. In summary, our findings reveal that chronic DP exposure can have a harmful effect on the intestinal flora balance and is potentially linked to human disease.

Nakamurella antarctica sp. nov., isolated from Antarctica South Shetland Islands soil.

A pale-yellow bacterial strain, designated S14-144T, was isolated from tundra soil sampled near the Antarctic Peninsula, South Shetland Islands (62° 22' 34″ S, 59° 42' 34″ W). The cells were strictly aerobic, Gram-stain-positive, non-motile and coccoid-shaped. Growth occurred at 4-28 °C, at pH 5.0-9.0 and in the presence of 0-5 % (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain S14-144T formed a lineage within the genus Nakamurella and shared the highest 16S rRNA gene sequence similarity with Nakamurella deserti 12Sc4-1T (96.5 %) and Nakamurella silvestrisS20-107T (96.4 %). The average nucleotide identity value between the genomes of strain 14-144T and the type strain of the species, N. deserti, was 72.0 % . The DNA G+C content of strain S14-144T was 61.6 mol% . The major cellular fatty acids of strain S14-144T were summed feature 3 (C16 : 1 ω7c and/or C16 : 1 ω6c) and C16 : 0. The strain contained MK-8(H4) as the predominant respiratory quinone, phosphatidylethanolamine and diphosphatidylglycerol as the major polar lipids, rhamnose, ribose and glucose as the major whole-cell sugars, and meso-diaminopimelic acid as the diagnostic diamino acid in the cell-wall peptidoglycan. On the basis of the phylogenetic, phenotypic and chemotaxonomic analysis, strain S14-144T is considered to represent a novel species of the genus Nakamurella, for which the name Nakamurella antarctica sp. nov. is proposed. The type strain is S14-144T (=CCTCC AB 2015345T=KCTC 39796T).

Nocardia yunnanensis sp. nov., an actinomycete isolated from a soil sample.

A novel actinomycete strain, designated CFH S0054T, was isolated from a soil sample collected from Xiaokongshan in Tengchong, Yunnan Province, in south-west PR China. Phylogenetic analysis based on its 16S rRNA gene sequence indicated that strain CFH S0054T belonged to the genus Nocardia. Based on the results of 16S rRNA gene sequence analysis, strain CFH S0054T was most closely related to Nocardia concava IFM 0354T (98.3 %), Nocardia inohanensis NBRC 100128T (97.9 %), Nocardia otitidiscaviarum NBRC 14405T (97.9 %) and Nocardia heshunensis CFH S0067T (97.8 %). Strain CFH S0054T contained C16 : 0, C18 : 1 ω9c, C18 : 0 10-methyl (TBSA) and summed feature 3 as major cellular fatty acids and MK-8 (H4ω-cycl) as the major respiratory quinone. The polar lipid profile included phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylinositol, phosphatidylinositol mannoside and unknown phospholipids. The cell wall contained meso-diaminopimelic acid, and the whole-cell hydrolysates were arabinose, galactose, glucose, fructose, ribose and mannose. The genome of strain CFH S0054T was 7.9 Mbp with a G+C content of 68.4 mol%, the average nucleotide identity (ANI) values between strain CFH S0054T and N. concava IFM0354T were low (ANIm<87.7 % and ANIb=84.1 %). On the basis of phylogenetic, physiological and chemotaxonomic data, strain CFHS0054T is considered to represent a novel species of the genus Nocardia, for which the name Nocardiayunnanensis sp. nov. is proposed, The type strain is CFH S0054T (DSM 46763T=JCM 30082T).

Effects of Lactococcus lactis from Cyprinus carpio L. as probiotics on growth performance, innate immune response and disease resistance against Aeromonas hydrophila.

In the present study, we reported 18 LAB strains isolated from the intestinal contents of Cyprinus carpio, and their probiotic properties both in vitro and in vivo. The results showed that 9 of them had higher in vitro immunomodulatory properties, effectively survived under acidic (pH 2.5) and bile salt (ranging from 0.1% to 0.5%) conditions, and inhibited the growth of 4 pathogens. Among them, Lactococcus lactis Q-8, Lactococcus lactis Q-9, and Lactococcus lactis Z-2 showed the strongest adhesion abilities and inhibition of pathogen adhesion to mucin. When the fish consumed diets containing these 3 strains (5 × 108 CFU/g) for 8 weeks, the weight gain (WG) and specific growth rate (SGR) had significantly (P < 0.05) increased, especially with L. lactis Q-8, which had a WG of 231.45%, and SGR of 2.22%. Survival rate in each LAB supplementation group was also significantly higher than that in control group during the feeding period (P < 0.05). For the cytokines expression levels in serum, different expression patterns were also observed. Before the infection with Aeromonas hydrophila, L. lactis supplementation significant up-regulated protein levels of pro-inflammatory cytokines (TNF-α, IL-1ß, IL-6, IL-12) compared with negative (CK1) group, while these cytokines were significantly lower than those in positive (CK2) group after infection. However, whether infected or not, the expression of anti-inflammatory cytokines (IL-10, TGF-ß) were significantly increased in L. lactis Q-8, L. lactis Q-9, and L. lactis Z-2 treatment groups. In conclusion, these 3 L. lactis strains screened from common carp were effective in improving growth, innate immunity and disease resistance. Based on the physiological characteristics in our study, they might be used as potential probiotics in aquaculture.

Effects of cadmium exposure on the composition and diversity of the intestinal microbial community of common carp (Cyprinus carpio L.).

Cadmium (Cd) is an environmental pollutant that poses serious health hazards. Due to the increasing contamination of aquatic systems with Cd, the increased accumulation of Cd in fish has become a food safety and public health concern. The present study was conducted to investigate the effects of waterborne Cd exposure on the microbial community composition and diversity in the gut of common carp. Common carp were exposed to three waterborne Cd concentrations (0, 50 and 500 µg Cd L-1) for 4 weeks. Our results indicated that Cd exposure profoundly affected the composition of the gut microbiota in the common carp. At the phylum level, Saccharibacteria were detected in only the 0 µg and 50 µg Cd L-1 exposure groups, and the abundance of Fusobacteria decreased with increasing Cd concentration, while the abundance of Firmicutes increased with increasing Cd concentration. At the genus level, Cetobacterium was the dominant group in the gut of the common carp, and the abundance of Cetobacterium decreased after Cd exposure. Notably, the abundance of Akkermansia muciniphila, a probiotic, was found to decrease after Cd exposure, and the proportions of some Cd-resistant bacteria were found to increase following Cd exposure. Our results also demonstrated that Cd exposure decreased the community diversity of the gut microbiota. These results suggest that Cd exposure may impact the gut homeostasis of common carp and further affect the health of the organism.

Dietary supplementation with Rehmannia glutinosa affects the composition of intestinal microorganisms in common carp.

A feeding experiment was conducted to investigate the effects of Rehmannia glutinosa (RG) on the bacterial, archaeal, and fungal community composition in the gut of common carp (Cyprinus carpio L.). Common carp were given a control diet and an RG-supplemented diet (basal diet plus 4% prepared Rehmannia root powder) over a period of 80 days. Our results indicated that the bacteria Fusobacteria, Proteobacteria, and Bacteroidetes; the archaea Crenarchaeota and Euryarchaeota; and the fungi Basidiomycota are the most abundant microbial taxa in the gut of common carp. Compared with the common carp fed a control diet, the common carp fed an RG-supplemented diet contained a higher content of Akkermansia sp., and a lower proportion of Aeromonas sp. These results indicate that the consumption of a diet containing RG can lead to the accumulation of more beneficial microorganisms while inhibiting the growth of potential pathogens. Moreover, Crenarchaeota, the methanogenic, and Basidiomycota were detected in this study, these populations may be of high physiological relevance in carp because they have been implicated in human health and disease. Our results suggest that an RG-supplemented diet changes the intestinal microbial composition of common carp, which could have positive effects on the immune response of carp.

Undibacterium arcticum sp. nov., isolated from arctic alpine soil.

A Gram-stain-negative, aerobic, motile rod-shaped bacterium, designated 6-67T, was isolated from a soil sample collected from Longyearbyen, Svalbard. Its taxonomic position was investigated by genotypic, phenotypic and chemotaxonomic analyses. This isolate grew at 4-28 °C (optimum, 20 °C), at pH 5.0-9.0 (optimum, pH 7.0) and with 0-0.2 % (w/v) NaCl. Strain 6-67T contained Q-8 as a major respiratory quinone and MK-7 as a minor component; the major fatty acids were summed feature 3 (C16 : 1ω6c and/or C16 : 1ω7c) and C16 : 0. The major polar lipids were phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, two unidentified phospholipids and one unidentified aminophospholipid. The polyamines were putrescine and 2-hydroxyputrescine. 16S rRNA gene sequence analysis indicated that the novel strain 6-67T belonged to the family Oxalobacteraceae within the class Betaproteobacteria. The DNA G+C content of strain 6-67T was 56.21 mol%. On the basis of phylogenetic, physiological and chemotaxonomic data, strain 6-67T is considered to represent a novel species of the genus Undibacterium, for which the name Undibacterium arcticum sp. nov. is proposed. The type strain is 6-67T (=CCTCC AB 2015162T=KCTC 42986T).

Sphingoaurantiacus polygranulatus gen. nov., sp. nov., isolated from high-Arctic tundra soil, and emended descriptions of the genera Sandarakinorhabdus, Polymorphobacter and Rhizorhabdus and the species Sandarakinorhabdus limnophila, Rhizorhabdus argentea and Sphingomonas wittichii.

An orange, Gram-reaction-negative and aerobic bacterium, designated MC 3718T, was isolated from a tundra soil near Ny-Ålesund, Svalbard archipelago, Norway (78° N). The cells were motile with either a polar or a subpolar flagellum and reproduced by budding or asymmetrical cell division. Growth occurred at 4-37 °C (optimum 28-30 °C) and at pH 6.0-10.0 (optimum pH 9.0). Many cells accumulated poly-ß-hydroxybutyrate granules and contained a single large polyphosphate granule at a pole or in the middle of the cell. Cell walls contained meso-diaminopimelic acid as the diagnostic diamino acid, and ubiquinone 10 was the main respiratory quinone. Strain MC 3718T contained summed feature 3 (comprising C16 : 1ω7c and/or C16 : 1ω6c; 29.49 %), summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c; 29.38 %), C17 : 1ω6c (10.15 %), C14 : 0 2-OH (9.05 %) and C16 : 0 (6.84 %) as the major cellular fatty acids. The main polar lipids were two sphingoglycolipids, phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylglycerol, three unknown phospholipids and two unknown polar lipids. Carotenoids were detected. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain MC 3718T belonged to the family Sphingomonadaceae. The DNA G+C content was 67.2 mol%. On the basis of phenotypic, chemotaxonomic and phylogenetic data, strain MC 3718T is considered to represent a novel genus and species in the family Sphingomonadaceae, for which the name Sphingoaurantiacus polygranulatus gen. nov., sp. nov. is proposed. The type strain of Sphingoaurantiacus polygranulatus is MC 3718T ( = CCTCC AB 2014274T = LMG 28636T). Emended descriptions of the genera Sandarakinorhabdus, Polymorphobacter and Rhizorhabdus and the species Sandarakinorhabdus limnophila, Rhizorhabdus argentea and Sphingomonas wittichii are also provided.

Mucilaginibacter antarcticus sp. nov., isolated from tundra soil.

The novel, pale yellow bacterial strain, designated S14-88T, was isolated from a tundra soil near Antarctic Peninsula, South Shetland Islands, and its taxonomic position was investigated by a genotypic and phenotypic analysis. Cells were facultatively anaerobic, Gram-stain-negative, non-motile and rod-shaped. Growth occurred at 4-28 °C (optimum at 15 °C), at pH 7.0-8.0 (optimum at 7.0) and with 0-0.6 % (w/v) NaCl (optimum, no NaCl). Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain S14-88T formed a lineage within the genus Mucilaginibacter. The 16S rRNA gene sequence similarity between strain S14-88T and the type strains of related species ranged from 92.2 to 96.5 %, and the 16S rRNA gene sequence of S14-88T showed highest similarity of 96.5 % to Mucilaginibacter soyangensis HME6664T. The major cellular fatty acids of strain S14-88T were iso-C15 : 0 and summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c). The major respiratory quinone was menaquinone MK-7, and the main polar lipid was phosphatidylethanolamine. The DNA G+C content of strain S14-88T was 42.3 mol%. On the basis of the evidence presented in this study, strain S14-88T is considered to represent a novel species of the genus Mucilaginibacter, for which the name Mucilaginibacter antarcticus sp. nov. is proposed. The type strain is S14-88T (=CCTCC AB 2015321T=KCTC 52232T).

Pseudorhodobacter collinsensis sp. nov., isolated from a till sample of an icecap front.

A Gram-stain-negative, rod-shaped, aerobic and non-motile strain, designated 4-T-34T, was isolated from a till sample of Collins icecap front, Antarctica, and its taxonomic position was investigated by genotypic, phenotypic and chemotaxonomic analysis. The isolate grew at 4-30 °C (optimum 20-25 °C), at pH 6.0-10.0 and with 0-1.0 % (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain 4-T-34T belonged to the genus Pseudorhodobacter, with the closest relatives being Pseudorhodobacter wandonensis WT-MW11T (96.9 % 16S rRNA gene sequence similarity), Pseudorhodobacter antarcticus ZS3-33T (96.8 %), Pseudorhodobacter ferrugineus IAM 12616T (96.5 %) and Pseudorhodobacter aquimaris HDW-19T (95.4 %). Strain 4-T-34T contained Q-10 as the only ubiquinone and C18 : 1ω7c as the major fatty acid. The major polar lipids were phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, two unidentified aminophospholipids and two unidentified phospholipids. The DNA G+C content of strain 4-T-34T was 61 mol%. On the basis of phylogenetic, physiological and chemotaxonomic data, strain 4-T-34T is considered to represent a novel species of the genus Pseudorhodobacter, for which the name Pseudorhodobacter collinsensis sp. nov. is proposed. The type strain is 4-T-34T ( = CCTCC AB 2014005T = LMG 28256T).

Chryseobacterium frigidum sp. nov., isolated from high-Arctic tundra soil, and emended descriptions of Chryseobacterium bernardetii and Chryseobacterium taklimakanense.

A yellow, Gram-reaction-negative, non-motile, aerobic bacterium, designated D07T, was isolated from a tundra soil near Ny-Ålesund, Svalbard archipelago, Norway (78° N). Growth occurred at 4-37 °C (optimum 28-30 °C) and at pH 6.0-9.0 (optimum pH 7.0-8.0). The strain produced flexirubin-type pigments. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain D07T belonged to the genus Chryseobacterium in the family Flavobacteriaceae. The 16S rRNA gene sequence of this strain showed 93.83 and 93.31 % sequence similarity, respectively, to those of Chryseobacterium contaminans C26T and Chryseobacterium taklimakanense X-65T. Strain D07T contained anteiso-C15 : 0 (25.91 %), iso-C15 : 0 (16.05 %), iso-C16 : 0 3-OH (9.64 %), iso-C16 : 0 (9.42 %) and iso-C14 : 0 (7.36 %) as the predominant cellular fatty acids, MK-6 as the major respiratory quinone and phosphatidylethanolamine, five unknown aminolipids and three unknown lipids as the main polar lipids. The DNA G+C content was 49.3 mol%. On the basis of phenotypic, chemotaxonomic and phylogenetic data, strain D07T is considered to represent a novel species of the genus Chryseobacterium, for which the name Chryseobacterium frigidum sp. nov. is proposed. The type strain is D07T ( = CCTCC AB 2011160T = KCTC 42897T). Emended descriptions of Chryseobacterium bernardetii and Chryseobacterium taklimakanense are also provided.

Flavobacterium collinsense sp. nov., isolated from a till sample of an Antarctic glacier.

A novel rod-shaped, Gram-stain-negative, non-gliding and aerobic strain surrounded by a multilayer capsule, designated 4-T-2T, was isolated from a till sample of Collins glacier front, Antarctica. The bacterium formed yellow, circular, convex and smooth colonies. Growth occurred at 4-28 °C (optimum18-20 °C), at pH 7.0-10.0 (optimum pH 9.0) and with 0-1 % NaCl. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain 4-T-2T belonged to the genus Flavobacterium. Strain 4-T-2T shared the highest 16S rRNA gene sequence similarity with the type strain of Flavobacterium algicola (96.7 %). The DNA G+C content of strain 4-T-2T was 36.2 mol%. The only menaquinone was MK-6. The major cellular fatty acids were iso-C15 : 0, iso-C15 : 1 G, iso-C16 : 0 and summed feature 9 (comprising iso-C17 : 1ω9c and/or 10-methyl C16 : 0). Polar lipid profile consisted phosphatidylethanolamine, one unidentified aminolipid, one unidentified aminophospholipid and one unidentified lipid. On the basis of phylogenetic, physiological and chemotaxonomic data, strain 4-T-2T is considered to represent a novel species of the genus Flavobacterium, for which the name Flavobacterium collinsense sp. nov. is proposed. The type strain is 4-T-2T ( = CCTCC AB 2014004T = LMG 28257T).