Microbacterium salsuginis sp. nov., a halotolerant actinobacterium with antimicrobial activity.

A novel Gram-staining-positive actinobacterium with antimicrobial activity, designated CFH 90308T, was isolated from the sediment of a salt lake in Yuncheng, Shanxi, south-western China. The isolate exhibited the highest 16S rRNA gene sequence similarities to Microbacterium yannicii G72T, Microbacterium hominis NBRC 15708T and Microbacterium xylanilyticum S3-ET (98.5, 98.4 and 98.2 %, respectively), and formed a separate clade with M. xylanilyticum S3-ET in phylogenetic trees. The strain grew at 15-40 ºC, pH 6.0-8.0 and could tolerate NaCl up to a concentration of 15 % (w/v). The whole genome of strain CFH 90308T consisted of 4.33 Mbp and the DNA G+C content was 69.6 mol%. The acyl type of the peptidoglycan was glycolyl and the whole-cell sugars were galactose and mannose. The cell-wall peptidoglycan mainly contained alanine, glycine and lysine. The menaquinones of strain CFH 90308T were MK-12, MK-13 and MK-11. Strain CFH 90308T contained anteiso-C15:0, anteiso-C17:0, iso-C16:0 and iso-C15:0 as the predominant fatty acids. The average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between CFH 90308T and the other species of the genus Microbacterium were found to be low (ANIb <81.3 %, dDDH <25.6 %). The secondary metabolite produced by strain CFH 90308T showed antibacterial activities against Bacillus subtilis, Pseudomonas syringae, Aeromonas hydrophila and methicillin-resistant Staphylococcus aureus. Based on genotypic, phenotypic and chemotaxonomic results, the isolate is considered to represent a novel species of the genus Microbacterium, for which the name Microbacterium salsuginis sp. nov. is proposed. The type strain is CFH 90308T (=DSM 105964T=KCTC 49052T).

Flagellimonas halotolerans sp. nov., a novel bacterium isolated from the South China Sea.

Two Gram-stain-negative strains, designed SYSU M86414T and SYSU M84420, were isolated from marine sediment samples of the South China Sea (Sansha City, Hainan Province, PR China). These strains were aerobic and could grow at pH 6.0-8.0 (optimum, pH 7.0), 4-37 °C (optimum, 28 °C), and in the presence of 0-10 % NaCl (w/v; optimum 3 %). The predominant respiratory menaquinone of strains SYSU M86414T and SYSU M84420 was MK-6. The primary cellular polar lipid was phosphatidylethanolamine. The major cellular fatty acids (>10 %) in both strains were iso-C15 : 0, iso-C15 : 1 G, and iso-C17 : 0 3-OH. The DNA G+C content of strains SYSU M86414T and SYSU M84420 were both 42.10 mol%. Phylogenetic analyses based on 16S rRNA gene sequences and core genes indicated that these novel strains belonged to the genus Flagellimonas and strain SYSU M86414T showed the highest 16S rRNA gene sequence similarity to Flagellimonas marinaquae JCM 11811T (98.83 %), followed by Flagellimonas aurea BC31-1-A7T (98.62 %), while strain SYSU M84420 had highest 16S rRNA gene sequence similarity to F. marinaquae JCM 11811T (98.76 %) and F. aurea BC31-1-A7T (98.55 %). Based on the results of polyphasic analyses, strains SYSU M86414T and SYSU M84420 should be considered to represent a novel species of the genus Flagellimonas, for which the name Flagellimonas halotolerans sp. nov. is proposed. The type strain of the proposed novel isolate is SYSU M86414T (=GDMCC 1.3806T=KCTC 102040T).

In vivo evidence of sea buckthorn relieving oxidative stress and improving immune performance of common carp (Cyprinus carpio L.).

BACKGROUND: Sea buckthorn has the functions of antioxidation, antitumor, anti-inflammation and regulating energy metabolism. In order to investigate the effects of sea buckthorn powder and sea buckthorn flavonoids on the antioxidant properties, immune function and muscle fatty acid composition of common carp, an oral feeding experiment was carried out. RESULTS: The administration of glucose significantly reduced the levels of glutathione and the activity of total antioxidant capacity enzyme in serum and hepatopancreas, while concurrently upregulating the level of malondialdehyde (MDA)(P < 0.05). Conversely, oral intake of sea buckthorn powder and flavonoids increased antioxidant enzyme activity and decreased MDA levels. In terms of antioxidant molecular indicators, sea buckthorn powder and sea buckthorn flavonoids significantly increased the mRNA levels of nuclear factor NF-E2-related factor (nrf2) in the hepatopancreas and muscle. Meanwhile, mRNA expression levels of downstream antioxidant-related genes (gr, cat, gpx, and sod) regulated by Nrf2 were also upregulated. In the immune aspects, the mRNA expression levels of proinflammatory cytokines, such as interleukin-6 (il-6), interleukin-1ß (il-1ß) and nuclear factor-κB (nf-κb), were reduced but the expressions of anti-inflammatory cytokines, such as growth factor-ß (tgf-ß) and interleukin-10 (il-10), were enhanced in the head kidney and spleen tissues after oral administration with sea buckthorn. In terms of muscle fatty acid composition, the ratio of n-3 polyunsaturated fatty acid (PUFA)/n-6 PUFA was notably higher after administering sea buckthorn flavonoids than that of the glucose group (P < 0.05). CONCLUSION: This study demonstrated that oral administration of sea buckthorn powder and sea buckthorn flavonoids significantly enhanced the antioxidant capacity and immune response and improved the muscle fatty acid compositions in common carp, and also mitigated the adverse effects of glucose treatment to a certain extent. © 2024 Society of Chemical Industry.

Environmental cadmium exposure perturbs systemic iron homeostasis via hemolysis and inflammation, leading to hepatic ferroptosis in common carp (Cyprinus carpio L.).

Cadmium (Cd) pollution is considered a pressing challenge to eco-environment and public health worldwide. Although it has been well-documented that Cd exhibits various adverse effects on aquatic animals, it is still largely unknown whether and how Cd at environmentally relevant concentrations affects iron metabolism. Here, we studied the effects of environmental Cd exposure (5 and 50 µg/L) on iron homeostasis and possible mechanisms in common carp. The data revealed that Cd elevated serum iron, transferrin saturation and iron deposition in livers and spleens, leading to the disruption of systemic iron homeostasis. Mechanistic investigations substantiated that Cd drove hemolysis by compromising the osmotic fragility and inducing defective morphology of erythrocytes. Cd concurrently exacerbated hepatic inflammatory responses, resulting in the activation of IL6-Stat3 signaling and subsequent hepcidin transcription. Notably, Cd elicited ferroptosis through increased iron burden and oxidative stress in livers. Taken together, our findings provide evidence and mechanistic insight that environmental Cd exposure could undermine iron homeostasis via erythrotoxicity and hepatotoxicity. Further investigation and ecological risk assessment of Cd and other pollutants on metabolism-related effects is warranted, especially under the realistic exposure scenarios.

Spexin acts as a novel glucose-lowering factor in grass carp (Ctenopharyngodon idella).

At present, the physiological roles of various hormones in fish glucose metabolism have been elucidated. Spexin, a 14-amino acids polypeptide, is highly conserved in many species and has functions such as reducing body weight and improving insulin resistance. In this paper, the open reading frame (ORF) of spx21 in grass carp (Ctenopharyngodon idella) was cloned, and the tissue distribution of spx1 and spx2, their direct and indirect regulatory effects on glucose metabolism of grass carp were investigated. The ORF of spx2 gene in grass carp was 279 bp in length. Moreover, spx1 was highly expressed in the adipose tissue, while spx2 was highly expressed in the brain. In vitro, SPX1 and SPX2 showed opposite effects on the glycolytic pathway in the primary hepatocytes. In vivo, intraperitoneal injection of SPX1 and SPX2 significantly reduced serum glucose levels and increased hepatopancreas glycogen contents. Meanwhile, SPX1 and SPX2 promoted the expression of key genes of glycolysis (pk) and glycogen synthesis (gys) in the hepatopancreas at 3 h post injection. As for indirect effects, 1000 nM SPX1 and SPX2 significantly increased insulin-mediated liver type phosphofructokinase (pfkla) mRNA expression and enhanced the inhibitory effects of insulin on glucose-6-phosphatase (g6pase), phosphoenolpyruvate carboxykinase (pepck), glycogen phosphorylase L (pygl) mRNA expression. Our results show that SPX1 and SPX2 have similar indirect effects on the regulation of glucose metabolism that enhance insulin activity, but they exhibit opposite roles in terms of direct effects.

Improvement of sea buckthorn (Hippophae rhamnoides L.) flavonoids on the antioxidant and immune performance of Yellow River carp (Cyprinus carpio L.) fed high-carbohydrate diet.

High-carbohydrate (HC) diets may lead to the deterioration of the antioxidant and immune properties of Yellow River carp and the healthy development of the industry. Studies in mammals have found that sea buckthorn flavonoids (SF) improve antioxidant and immune performance. Therefore, this study comprehensively evaluated the effects of SF on Yellow River carp using in vitro and feeding trials with an HC diet. Control (C, 27.23 %), high-carbohydrate (HC, 42.99 %), and HC + SF (0.1 %, 0.2 %, and 0.4 %) groups were studied in a 10-week aquaculture experiment. The main findings were as follows: (1) SF scavenged O2·-, ·OH, and DPPH free radicals in vitro, which gradually increased with the SF concentration. (2) The antioxidant and immune performance of Yellow River carp was enhanced by dietary supplementation with SF, which involved the regulation of activities of antioxidant and immune enzymes, as well as their changes at the transcription and protein levels. In terms of antioxidant properties, compared to the HC group, HC + SF significantly decreased the activities of glutamic-oxaloacetic transaminase and glutamic-pyruvic transaminase and the contents of H2O2 and malondialdehyde in the serum and hepatopancreas. The activities of glutathione, glutathione-Px, superoxide dismutase, catalase, and total antioxidant activity in the HC-diet group. In contrast, the addition of SF increased antioxidant enzyme activity. In the hepatopancreas and muscles, SF regulated and activated Nrf2-Keap1, a key signaling pathway for oxidative stress. SF significantly increased the mRNA expression levels of downstream genes (gr, ho-1, cat, and sod) regulated by nrf2. In terms of immune performance, 0.4 % SF markedly increased the activity of immune-related enzymes. SF inhibited the gene expression of pro-inflammatory factors induced by the HC diet and promoted the gene expression of anti-inflammatory factors. In addition, the resistance of Yellow River carp to Aeromonas hydrophila was enhanced by SF. In summary, SF supplementation can reduce oxidative stress and inflammatory harm caused by the HC diet and improve the antioxidant and immune performance of Yellow River carp to varying degrees.

Cereibacter flavus sp. nov., a novel member of the family Rhodobacteraceae isolated from seawater of the South China Sea and reclassification of Rhodobacter alkalitolerans as Cereibacter alkalitolerans comb. nov.

A Gram-stain-negative, aerobic, motile, ovoid-shaped and yellow-coloured strain, designated SYSU M79828T, was isolated from seawater collected from the South China Sea. Growth of this strain was observed at 4-37 °C (optimum, 28 °C), pH 6.0-8.0 (optimum, pH 7.0) and with 0-6% NaCl (optimum, 3.0 %, w/v). The respiratory quinone was found to be Q-10. Major fatty acid constituents were C18 : 1 ω7c/C18 : 1 ω6c, C18 : 1 ω7c11-methyl and C18 : 0 (>5 % of total). The major polar lipids were phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylcholine, phosphoglycolipid, two unidentified phospholipid, one unidentified lipid and an unidentified glycolipid. The genomic DNA G+C content was 64.5 mol%. Phylogenetic analyses based on 16S rRNA gene sequences and core genes indicated that strain SYSU M79828T belonged to the genus Cereibacter and had the highest sequences similarity to 'Rhodobacter xinxiangensis' TJ48T (98.41 %). Based on 16S rRNA gene phylogeny, physiological and chemotaxonomic characterizations, we consider that strain SYSU M79828T represents a novel species of the genus Cereibacter, for which the name Cereibacter flavus sp. nov. is proposed. The type strain is SYSU M79828T (=GDMCC 1.3803T=KCTC 92893T). In addition, according to the results of phylogenetic analysis and similar taxonomic characteristics, we propose that Rhodobacter alkalitolerans should be reclassified as Cereibacter alkalitolerans comb. nov.

Effects of Genistein on Lipid Metabolism, Antioxidant Activity, and Immunity of Common Carp (Cyprinus carpio L.) Fed with High-Carbohydrate and High-Fat Diets.

A 56-day feeding trial was conducted to investigate the effects of genistein on growth, lipid metabolism, antioxidant capacity, and immunity of common carp fed with high-carbohydrate or high-fat diets. Five diets were used to feed fish: control diet (5% fat; CO), high-fat diet (11% fat; HF), high-carbohydrate diet (45% carbohydrate; HC), and HF or HC diet with 500 mg/kg genistein (FG or CG). Results showed that final body weight (FW) and specific growth rate (SGR) were significantly reduced, but the supplementation with genistein resulted in higher values of FW and SGR than the HF or HC group. Both high carbohydrate and high fat belong to high-energy diets, which may promote lipid deposition. Genistein obviously decreased liver triglyceride (TG) content and alleviated hepatic fat vacuolation in the HF and HC groups. The expression of lipid metabolism genes (cpt-1 and atgl) was markedly higher in the FG group than in the HF group. The lipid synthesis-related genes (fas, acc, and pparγ) were elevated in high-energy diets but recovered to the control level or reduced after genistein treatments. With respect to fatty acid transporter genes, fatp increased in the FG group, and cd36 increased in the CG group. Furthermore, the antioxidant and immune indexes, such as total antioxidant capacity (T-AOC), glutathione peroxidase (GSH-PX), superoxide dismutase (SOD), acid phosphatase (ACP), and lysozyme (LZM) activities, were decreased, while malonate aldehyde (MDA) content, activities of alanine aminotransferase (ALT), and aspartate aminotransferase (AST) were enhanced in the HF and HC groups. The antioxidant and immunity values could be ameliorated by treatment with genistein. Moreover, the transcript levels of antioxidant-related genes (cat, gr, and nrf2) in the liver and anti-inflammatory factors (tgf-ß and il-10) and lyz in the head kidney tissue were promoted, although the expression levels of proinflammatory factors (tnf-α and il-6) declined in the genistein supplementation group, which confirmed the antioxidant and immune-enhancing effects of genistein. Therefore, 500 mg/kg genistein could ameliorate the negative effects of high-energy diets on immunity.

Panguiarchaeum symbiosum, a potential hyperthermophilic symbiont in the TACK superphylum.

The biology of Korarchaeia remains elusive due to the lack of genome representatives. Here, we reconstruct 10 closely related metagenome-assembled genomes from hot spring habitats and place them into a single species, proposed herein as Panguiarchaeum symbiosum. Functional investigation suggests that Panguiarchaeum symbiosum is strictly anaerobic and grows exclusively in thermal habitats by fermenting peptides coupled with sulfide and hydrogen production to dispose of electrons. Due to its inability to biosynthesize archaeal membranes, amino acids, and purines, this species likely exists in a symbiotic lifestyle similar to DPANN archaea. Population metagenomics and metatranscriptomic analyses demonstrated that genes associated with amino acid/peptide uptake and cell attachment exhibited positive selection and were highly expressed, supporting the proposed proteolytic catabolism and symbiotic lifestyle. Our study sheds light on the metabolism, evolution, and potential symbiotic lifestyle of Panguiarchaeum symbiosum, which may be a unique host-dependent archaeon within the TACK superphylum.

Fatty hepatocytes-derived exosomal miR-122 reduces immune function and antioxidant defence in Ctenopharyngodon idella kidney (CIK) cells.

Exosomes are important for intercellular "cross talk", but the role of exosomes in communication between hepatocytes and C. idella kidney (CIK) cells remains unknown. In this study, we detected the changes in factors related to immune and oxidative stress to investigate the molecular mechanism by which fatty hepatocyte-derived exosomes (OA-Exos) reduced immunity and induced oxidative stress in CIK cells. After incubation of CIK cells by OA-Exos for 24 h, tumor necrosis factor-α (TNF-α), nuclear factor-κB (NF-κB) and interleukin-1ß (IL-1ß) were significantly upregulated in the OA-Exos group (P < 0.05), and Mn superoxide dismutase (Mn-SOD) and heme oxygenase-1 (HO-1) were significantly downregulated (P < 0.05). Surprisingly, miR-122 expression was also significantly elevated after OA-Exos incubation. We further identified the expression of miR-122 and found that it was notably increased in OA-Exos compared to hepatocyte-derived exosomes (Exos). Then we transfected CIK cells with miR-122 mimic, consistently, the expression of inflammatory cytokines was also significantly elevated (P < 0.05), and the expression of glutathione peroxidase (GPx), HO-1, and Mn-SOD were dramatically decreased (P < 0.05). Furthermore, HO-1 was improved to be a direct target of miR-122, and transfection with HO-1 siRNA indicated that changes in inflammatory cytokines and genes related to oxidative stress were consistent with the above results of CIK cells incubated with OA-Exos and miR-122 mimic. We concluded that OA-Exos may, through the miR-122/HO-1 pathway, reduce immune function and antioxidant defence in CIK cells.

Distinct responses from triglyceride and cholesterol metabolism in common carp (Cyprinus carpio) upon environmental cadmium exposure.

Due to high persistence and bioavailability, Cadmium (Cd) is one of the most prevalent environmental contaminants, posing an elevating threat to the ecosystems. It has been evidenced that high-dose Cd elicits deleterious effects on aquatic organisms, but the potential toxicities of Cd at environmentally relevant concentrations remains underappreciated. In this study, we used common carp to investigate how environmental Cd exposure affects triglyceride (TG) and cholesterol metabolism and underlying mechanisms. The data indicated that Cd resulted in the shift of TG from the liver to blood and the movement of cholesterol in the opposite direction, ultimately giving rise to the storage of crude lipid in liver and muscle, especially hepatic cholesterol retention. Cholesterol, instead of TG, became the principal cause during the progression of hepatic lipid accumulation. Mechanistic investigations at transcriptional and translational levels further substantiated that Cd blocked hepatic biosynthesis of TG and enhanced TG efflux out of the liver and fatty acid ß-oxidation, which collectively led to the compromised TG metabolism in the liver and accelerated TG export to the serum. Additionally, strengthened synthesis, retarded export and oxidation of cholesterol detailed the hepatic prominent cholesterol retention. Taken together, our results demonstrated that environmental exposure to Cd perturbed lipid metabolism through triggering distinct responses from hepatic TG and cholesterol homeostasis. These indicated that environmental factors (such as waterborne Cd) could be a potential contributor to the prevalence of non-alcoholic fatty-liver disease in aquaculture and more efforts should be devoted to the ecological risk assessment of pollutants under environmental scenarios.

Agromyces agglutinans sp. nov., isolated from saline lake sediment.

A novel actinobacterium, designated strain CFH 90414T, was isolated from sediment sampled at a saline lake in Yuncheng, Shanxi, PR China. The taxonomic position of the strain was investigated by using a polyphasic approach. Cells of strain CFH 90414T were Gram-reaction-positive, aerobic and non-motile. Growth occured at 4-40 °C, pH 5.0-9.0 and in the presence of up to 0-3.0 % (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain CFH 90414T was a member of the genus Agromyces. The 16S rRNA gene sequence similarity analysis indicated that strain CFH 90414T was most closely related to Agromyces italicus JCM 14320T (98.07 %) and Agromyces lapidis JCM 14321T (97.18 %). The whole genome of CFH 90414T was 3.64 Mb, and showed a G+C content of 71.5 mol%. The average nucleotide identity (ANI) values and digital DNA-DNA hybridization (dDDH) values between CFH 90414T and the other species of the genus Agromyces were found to be low (ANI <78.99 % and dDDH <22.9 %). The whole-cell sugars were rhamnose, mannose, ribose, glucose and galactose. The isolate contained l-2,4-diaminobutyric acid, d-alanine, d-glutamic acid and glycine in the cell-wall peptidoglycan. The predominant menaquinone was MK-12. The major cellular fatty acids were anteiso-C15 : 0, anteiso-C17 : 0 and iso-C16 : 0. The polar lipid profile contained diphosphatidylglycerol, phosphatidylglycerol and an unidentified glycolipid. On the basis of phenotypic, genotypic and phylogenetic data, strain CFH 90414T is considered to represent a novel species of the genus Agromyces, for which the name Agromyces agglutinans sp. nov. is proposed. The type strain is CFH 90414T (=DSM 105966T=KCTC 49062T).

Devosia ureilytica sp. nov., isolated from Kuche River in China.

Two novel strains, designated XJ19-45T and XJ19-1, were isolated from water of Kuche River in Xinjiang Uygur Autonomous Region, China. Their cells were Gram-stain-negative, aerobic and motile rods. The phylogenetic analyses based on 16S rRNA genes and genomes showed that the two isolates belonged to the genus Devosia and the closest relative was Devosia subaequoris HST3-14T. The 16S rRNA genes sequences pairwise similarities, average nucleotide identities, digital DNA-DNA hybridizations and average amino acid identities between type strain XJ19-45T and other relatives were all less than 98.3, 80.3, 23.6 and 85.7 %, respectively, all below the species delineation thresholds. Pan-genomic analysis indicated that the novel isolate XJ19-45T shared 1594 core gene clusters with the 11 closely related type strains in Devosia, and the number of strain-specific clusters was 390. The major cellular fatty acids (>10 %) of the two isolates were summed feature 8, C18 : 1 ω7c 11-methyl and C16 : 0. Diphosphatidylglycerol, phosphatidylglycerol and glycolipids were the major polar lipids, and Q10 was the detected respiratory quinone. Based on the results of phenotypic, physiological, chemotaxonomic and genotypic characterizations, we propose that the isolates represent a novel species, for which the name Devosia ureilytica sp. nov. is proposed. The type strain is XJ19-45T (=CGMCC 1.19388T=KCTC 92263T).

Brachybacterium subflavum sp. nov., a novel actinobacterium isolated from the foregut of grass carp.

A novel actinobacterium, designated CFH 10395T, was isolated from the foregut of grass carp (Ctenopharyngodon idella), which had been fed with ginseng extract supplement. The taxonomic position was investigated by a polyphasic approach. Cells of CFH 10395T were Gram-staining-positive, aerobic, ovoid-shaped, non-spore-forming and non-motile. On the basis of the results of 16S rRNA gene sequence analysis, CFH 10395T was most closely related to Brachybacterium endophyticum KCTC 49087T, Brachybacterium squillarum JCM 16464T and Brachybacterium paraconglomeratum JCM 17781T (97.85%, 97.51 and 97.29% similarity, respectively). CFH 10395T grew at 4-37 °C, pH 5.0-9.0 and in the presence of up to 10.0 % NaCl (w/v). The dominant menaquinone was MK-7. The whole-cell sugars were rhamnose, glucose, mannose and galactose. meso-diaminopimelic acid was the diagnostic diamino acid in the cell-wall peptidoglycan. The major fatty acids were anteiso-C15 : 0, anteiso-C17 : 0 and iso-C16 : 0. The genome size was 3.99 Mbp with a DNA G+C content of 71.9 mol%. On the basis of the results of phylogenetic analysis, physiological properties, chemotaxonomic characteristics, low average nucleotide identity (ANI) and digital DDH (dDDH) results [ANI calculated using MUMmer (ANIm) <87 %, ANI calculated using blast (ANIb) <83 % and dDDH <23 %], it is concluded that CFH 10395T represents a novel species of the genus Brachybacterium, for which the name Brachybacterium subflavum sp. nov., is proposed. The type strain is CFH 10395T (=CGMCC 1.13804T=KCTC 49235T).

Transcriptome analysis of common carp (Cyprinus carpio) provides insights into the ovarian maturation related genes and pathways in response to LHRH-A and dopamine inhibitors induction.

Luteinizing hormone-releasing hormone analog (LHRH-A) and dopamine inhibitors have been widely used to induce oocyte maturation and ovulation in domesticated fishes. Although this approach represents a reliable method for regulating fish reproduction, the underlying molecular mechanisms mediating LH action are largely unexplored. The objective of this study was to determine the transcriptional profile of gene programming in hormone-treated common carp. In the present study, female common carp were intraperitoneally injected with LHRH-A together with dopamine inhibitors, and control fish were injected with saline. Ovarian morphological changes were analysed by both light microscopy and scanning electron microscopy. Furthermore, gene expression profiling of the brain and ovarian tissues was performed by Illumina sequencing. Compared to the control carp, hormone treatment resulted in morphological changes including disappearance of nuclear membrane, breakdown of germinal vesicle (GVBD), and fusion of yolk globules, reflecting that hormones significantly promoted oocyte maturation. In comparison to control, we have identified 867 and 9,053 differentially expressed genes in the hormone-treated female brain and ovary, respectively. In the brain, most of the identified genes were significantly enriched in 18 KEGG pathways. In the ovarian tissue, the identified genes were significantly involved in 9 pathways. In the hormone-treated carp, genes were involved in calcium signalling pathway, cAMP signalling pathway, insulin secretion, and oxidative phosphorylation pathway, which showed obvious associations with ovarian maturation. The present study provides transcriptomic information for hormone-treated carp, which might be useful for studying the endocrine regulation and mechanisms of ovarian maturation in domesticated fishes.

The Regulatory Role of Apelin on the Appetite and Growth of Common Carp (Cyprinus Carpio L.).

Apelin, a kind of active polypeptide, has many biological functions, such as promoting food intake, enhancing immunity, and regulating energy balance. In mammals, studies have indicated that apelin is involved in regulating food intake. However, there are relatively few studies about the regulatory effect of apelin on fish feeding, and the specific mechanism is not clear. Therefore, the purpose of this study was to preliminarily investigate the regulatory effects of apelin on key genes of feeding and growth in common carp (Cyprinus Carpio L.) through in vitro and in vivo experiments. In the present study, after incubation with different concentrations of Pyr-apelin-13 (0, 10, 100, and 1000 nM) in hypothalamic fragments, the expressions of Neuropeptide Y (NPY) and Agouti related peptide (AgRP) mRNA were significantly up-regulated at 12 and 3 h, respectively, and the significant down-regulation of Cocaine and amphetamine-related transcript (CART) mRNA expression was observed at 1 and 3 h. In vivo, after Pyr-apelin-13 oral administration (0, 1, 10, and 100 pmol/g), the orexin mRNA level in the hypothalamus of common carp was significantly increased at 1, 6, and 12 h, while CART/(Proopiomelanocortin) POMC mRNA levels in the hypothalamus of common carp were significantly down-regulated. Following incubation with different concentrations of Pyr-apelin-13 (0, 10, 100, and 1000 nM) in primary hepatocytes, GHR (Growth hormone receptor), IGF2 (Insulin-like growth factor 2), IGFBP2 (Insulin like growth factor binding protein 2), and IGFBP3 (Insulin like growth factor binding protein 3) mRNA levels were significantly increased at 3 h. In vivo, the levels of IGF1 (Insulin-like growth factor 1), IGF2, IGFBP2 (Insulin like growth factor binding protein 2), and IGFBP3 mRNA were significantly increased after the oral administration of Pyr-apelin-13 in the hepatopancreas, in a time and dose-dependent manner. These results support the hypothesis that Pyr-apelin-13 might regulate the feeding and growth of common carp through mediating the expressions of appetite- and growth-related genes. Overall, apelin, which is an orexigenic peptide, improves food intake and is involved in the growth of common carp.

Brevibacillus migulae sp. nov., isolated from a Yellow River sediment sample.

Strain CFH S0501T, a novel Gram-stain-positive, aerobic, rod-shaped, endospore-forming and motile micro-organism with peritrichous flagella, was isolated from a sediment sample collected from the Yellow River in Henan Province, PR China. Optimum growth was observed at 28 °C, pH 7.0 and without NaCl. Phylogenetic analysis based on the 16S rRNA gene sequences indicated that the strain belonged to the genus Brevibacillus and was closely related to Brevibacillus centrosporus DSM 8445T and Brevibacillus ginsengisoli Gsoil 3088T (with 96.8 and 96.7 % sequence similarity, respectively). The predominant menaquinone was MK-7. Major cellular fatty acids were anteiso-C15 : 0 and iso-C15 : 0. Polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylmonomethylethanolamine, phosphatidylethanolamine, two unidentified phospholipids and an unidentified polar lipid. The cell-wall peptidoglycan was found to contain meso-diaminopimelic acid. The genome size was 5.26 Mbp with a G+C content of 49.7 mol%. The average nucleotide identity (ANI) and in silico DNA-DNAhybridization (DDH) values between CFH S0501T and the other species of the genus Brevibacillus were found to be low (ANIm <86.11 %, ANIb <70.30 % and DDH <25.00 %). Based on physiological properties, chemotaxonomic characteristics and low ANI and DDH results, strain CFH S0501T is considered to represent a novel species, for which the name Brevibacillus migulae sp. nov. is proposed. The type strain is CFH S0501T (=DSM 29940T=BCRC 80809T).

Isoptericola halalbus sp. nov., a halotolerant actinobacterium isolated from saline lake sediment.

A novel Gram-stain-positive bacterium, designated CFH 91151T, was isolated from sediment collected from a saline lake in Yuncheng, Shanxi Province, PR China. Cells of strain CFH 91151T were rod-or v-shaped, aerobic, non-motile, non-spore-forming and halotolerant. Results of 16S rRNA gene sequence analysis revealed that strain CFH 91151T was closely related to Isoptericola variabilis MX5T and Isoptericola nanjingensis H17T (98.7 and 98.4% sequence similarity, respectively). The strain grew at 4-45 °C, pH 5.0-9.0 and with 0-14.0 % (w/v) NaCl. Cells were positive for catalase, nitrate was not used and H2S was not produced. Major cellular fatty acids were anteiso-C15 : 0 (62.76 %), anteiso-C17 : 0 (12.09 %) and iso-C15 : 0 (9.46 %). The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol, two unidentified phospholipids and three unidentified glycolipids. The menaquinone was MK-9 (H4). The genome size was 4.10 Mbp with a G+C content of 72.4 mol%. The average amino acid identity (ANI) and in silico DNA-DNA hybridization (DDH) values between CFH 91151T and the other species of the genus Isoptericola were found to be low (ANIm <87.19 %, ANIb <84.38 % and DDH <29.30 %). Based on physiological properties, chemotaxonomic characteristics and low ANI and DDH results, strain CFH 91151T is considered to represent a novel species, for which the name Isoptericola halalbus sp. nov. is proposed. The type strain is CFH 91151T (=DSM 105976T=KCTC 49061T).

Halomonas lactosivorans sp. nov., isolated from salt-lake sediment.

A bacteria strain, designated CFH 90008T, was isolated from a salt lake sediment sample collected from Yuncheng city, Shanxi Province, PR China. Strain CFH 90008T was Gram-stain-negative, strictly aerobic, motile with lateral flagella and rod-shaped. Colonies were yellow, circular and smooth. Phylogenetic analyses based on 16S rRNA gene sequences indicated that strain CFH 90008T belonged to the genus Halomonas, showing highest sequence similarity to Halomonas daqingensis DQD2-30T (98.6 %), Halomonas saliphila LCB169T (98.5 %), Halomonas desiderata FB2T (98.1 %) and Halomonas kenyensis AIR-2T (98.0 %). Good growth was observed at 10-50 °C, pH 6.0-9.0 and with NaCl concentration from 1.0 to 12.0 % (w/v). The predominant quinone was Q9. The major fatty acid (>10 %) was C18 : 1 ω7c, C16 : 0 and C16 : 1 ω7c. The genome of strain CFH 90008T was 4.36 Mbp with a genomic DNA G+C content of 66.7 mol%. Based on low average nucleotide identity and DNA-DNAhybridization results, chemotaxonomic characteristics, and differential physiological properties, strain CFH 90008T could not be classified into any recognized species of the genus Halomonas. Therefore, a new species, for which the name Halomonas lactosivorans sp. nov. is proposed. The type strain is CFH 90008T (=DSM 103220T=KCTC 52281T).

Amycolatopsis nivea sp. nov., isolated from a Yellow River sample.

A novel actinobacterium, designated strain CFH S0261T, was isolated from a sediment sample of the Yellow River. The taxonomic position of the strain was investigated by using a polyphasic approach. Cells of strain CFH S0261T were Gram-reaction-positive, aerobic, non-motile. Growth occurs at 15-37 °C, pH 6.0-8.0 and with 0-9.0 % (w/v) NaCl. Phylogenetic analysis based on the 16S rRNA gene sequence revealed that strain CFH S0261T was a member of the genus Amycolatopsis. The 16S rRNA gene sequence similarity indicated that strain CFH S0261T is most closely related to the type strains of Amycolatopsis niigatensis LC11T (98.95 %), Amycolatopsis echigonensis LC2T (98.81 %) and Amycolatopsis albidoflavus IMSNU 22139T (98.73 %). The whole-genome of CFH S0261T showed a G+C content of 69.5 mol%. The ANI values and in silico DDH values between CFH S0261T and the other species of the genus Amycolatopsis were found to be low (ANIb <90.61 % and DDH <53.40 %). The cell wall diamino acid in the peptidoglycan of strain CFH S0261T was meso-diaminopimelic acid and the whole-cell hydrolysate comprised arabinose, galactose, glucose, rhamnose and ribose. The predominant menaquinone was MK-9(H4). The major cellular fatty acids were C16 : 0, iso-C15 : 0 and iso-C16 : 0. The polar lipid profile contained diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol, phosphatidylinositol mannosides and four unidentified glycolipids. On the basis of phenotypic, genotypic and phylogenetic data, strain CFH S0261T represents a novel species of the genus Amycolatopsis, for which the name Amycolatopsis nivea sp. nov. is proposed. The type strain is CFH S0261T (=KCTC 39515T =CCTCC AA 2014028T).