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Thomas F.,Integrative Biology of Marine ModelsSorbonne University | Larocque R.,Integrative Biology of Marine ModelsSorbonne University | Li N.,State Key Laboratory of Freshwater Ecology and Biotechnology | Duffieux D.,Integrative Biology of Marine ModelsSorbonne University | And 3 more authors.
Environmental Microbiology | Year: 2017

Comprehension of the degradation of macroalgal polysaccharides suffers from the lack of genetic tools for model marine bacteria, despite their importance for coastal ecosystem functions. We developed such tools for Zobellia galactanivorans, an algae-associated flavobacterium that digests many polysaccharides, including alginate. These tools were used to investigate the biological role of AlyA1, the only Z. galactanivorans alginate lyase known to be secreted in soluble form and to have a recognizable carbohydrate-binding domain. A deletion mutant, ΔalyA1, grew as well as the wild type on soluble alginate but was deficient in soluble secreted alginate lyase activity and in digestion of and growth on alginate gels and algal tissues. Thus, AlyA1 appears to be essential for optimal attack of alginate in intact cell walls. alyA1 appears to have been recently acquired via horizontal transfer from marine Actinobacteria, conferring an adaptive advantage that might benefit other algae-associated bacteria by exposing new substrate niches. The genetic tools described here function in diverse members of the phylum Bacteroidetes and should facilitate analyses of polysaccharide degradation systems and many other processes in these common but understudied bacteria. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.


Ji Y.,Huazhong Agricultural University | Li J.,Huazhong Agricultural University | Qin Z.,Huazhong Agricultural University | Li A.,State Key Laboratory of Freshwater Ecology and Biotechnology | And 8 more authors.
Virulence | Year: 2015

Aeromonas hydrophila is a gram-negative bacterium that is widely distributed in aquatic environments and can cause septicemia in both fish and humans. However, the underlying mechanisms leading to severe infection are not well understood. In this study, an A. hydrophila nuclease (ahn) deletion mutant was constructed to investigate its contribution to pathogenesis. This mutant did not differ from the wild-type strain in terms of its growth or hemolytic phenotype. However, the ahn-deficient mutant was more susceptible to being killed by fish macrophages and mouse blood in vitro. Furthermore, evidence obtained using both fish and murine infection models strongly indicated that the inactivation of Ahn impaired the ability of A. hydrophila to evade innate immune clearance in vivo. More importantly, the virulence of the mutant was attenuated in both fish and mice, with reductions in dissemination capacities and mortality rates. These findings implicate Ahn in A. hydrophila virulence, with important functions in evading innate immune defenses. © 2015 Taylor & Francis Group, LLC.


Xiao J.,Hunan Normal University | Yan J.,Hunan Normal University | Chen H.,Hunan Normal University | Li J.,Hunan Normal University | And 5 more authors.
Fish and Shellfish Immunology | Year: 2016

Mx (myxovirus resistance) is an important antiviral protein in the innate immune responses of vertebrates to microbial pathogens. In this study, we cloned and characterized Mx1 of black carp (Mylopharyngodon piceus). The full-length cDNA of black carp Mx1 (bcMx1) consists of 2781 nucleotides and the predicted bcMx1 protein contains 631 amino acids. bcMx1 contains a GTPase domain at the N-terminnus, a “central interactive domain” in the middle and a GTPase effector domain at the C-terminus. bcMx1 mRNA was constitutively transcribed in all tissues tested, including the heart, liver, spleen, kidney, intestine, muscle, skin and gill; and bcMx1 mRNA levels increased in all but the gill after grass carp reovirus (GCRV) or viraemia of carp virus (SVCV) infection. Quantitative PCR analysis of Mylopharyngodon piceus fin (MPF) cells indicated that bcMx1 mRNA levels increased after GCRV or SVCV infection at different multiplicities of infection (MOI). Western blotting demonstrated that the molecular weight of bcMx1 is ∼75 kDa and immunofluorescent staining data of both HeLa cells and EPC cells showed that bcMx1 is a cytosolic protein. EPC cells transfected with plasmid expressing bcMx1 showed increased antiviral activity against SVCV and GCRV. All our data suggest that bcMx1 is an antiviral protein in the innate immune response of the black carp. © 2016 Elsevier Ltd


Zhou W.,Hunan Normal University | Zhou J.,Hunan Normal University | Lv Y.,Hunan Normal University | Qu Y.,Hunan Normal University | And 4 more authors.
Fish and Shellfish Immunology | Year: 2015

MAVS (mitochondria antiviral signaling protein) plays an important role in the host cellular innate immune response against microbial pathogens. In this study, MAVS has been cloned and characterized from black carp (Mylopharyngodon piceus). The full-length cDNA of black carp MAVS (bcMAVS) consists of 2352 nucleotides and the predicted bcMAVS protein contains 579 amino acids. Structural analysis showed that bcMAVS is composed of functional domains including an N-terminal CARD, a central proline-rich domain, a putative TRAF2-binding motif and a C-terminal TM domain, which is similar to mammalian MAVS. bcMAVS is constitutively transcribed in all the selected tissues including gill, kidney, heart, intestine, liver, muscle, skin and spleen; bcMAVS mRNA level in intestine, liver, muscle increased but decreased in spleen right after GCRV or SVCV infection. Multiple bands of bcMAVS were detected in western blot when it was expressed in tissue culture, which is similar to mammalian MAVS. Immunofluorescence assay determined that bcMAVS is a mitochondria protein and luciferase reporter assay demonstrated that bcMAVS could induce zebrafish IFN and EPC IFN expression in tissue culture. Data generated in this manuscript has built a solid foundation for further elucidating the function of bcMAVS in the innate immune system of black carp. © 2015 Elsevier Ltd.


Bobrov A.,Moscow State University | Qin Y.,Wuhan University | Qin Y.,State Key Laboratory of Freshwater Ecology and Biotechnology | Wilkinson D.M.,Liverpool John Moores University
Acta Protozoologica | Year: 2015

The extent to which free-living microorganisms show cosmopolitan distributions has been a contentious aspect of microbial ecology over the last few decades. Testate amoebae are a group of free living protists that can provide important evidence for the nature of the biogeography of microorganisms because there are relatively good data on the distribution of their morpho-species (compared to many other microbial groups). Many testate amoebae appear to exhibit ubiquitous distributions, while some taxa have proven to be endemic to limited regions. The genus Hoogenraadia (Gauthier-Lièvre and Thomas 1958) is of particular interest in this context as it appears to be restricted to relatively low latitudes. There are six described species of the genus: H. africana Gauthier-Lièvre and Thomas 1958, H. asiatica Wang and Min 1987, H. cryptostoma Gauthier-Lièvre and Thomas 1958, H. humicola Bonnet 1976, H. ovata Bonnet 1976, and H. sylvatica Vucetich 1974. However, information on these taxa is scattered through a number of different papers – here we provide a summary of what is known about the taxonomy and ecology of this genus. We also reinterpret recent new records of putative H. africana from China (suggesting this identification is not reliable). As an example of a protist taxon largely restricted to the tropics this genus is of particular interest in microbial biogeography and this paper discusses its morphology, ecology and distribution in this context. © 2015 Jagiellonian University. All rights reserved.


Wang H.-R.,Wuhan University | Chen D.-L.,Wuhan University | Zhao M.,Wuhan University | Shu S.-W.,State Key Laboratory of Freshwater Ecology and Biotechnology | And 4 more authors.
Kidney and Blood Pressure Research | Year: 2012

Background: Although C-reactive protein (CRP) is significantly increased in patients with diabetic nephropathy, whether CRP exerts direct proinflammatory effects on human renal tubular epithelial cells (HK-2 cells) is still unclear. Methods: HK-2 cells were incubated with purified CRP at clinically relevant concentrations (0, 5, 10, 20 and 40 μg/ml). The protein and transcript levels of thrombospondin-1 (TSP-1) and interleukin-6 (IL-6) were determined by ELISA and RT-PCR. Phosphorylation of p38MAPK was investigated through Western blot analysis in HK-2 cells induced by CRP. The activation of nuclear factor-kappa B (NF-κB) was studied via EMSA. A specific p38MAPK inhibitor (SB203580) and an NF-κB inhibitor (PDTC; pyrrolidine dithiocarbamate) were used to analyze the signal transduction in CRP induction. To explore the direct or indirect role of CRP in HK-2 cells, IL-6 or TSP-1 antibodies were used. The expression of IL-6, TSP-1 and transforming growth factor-β1(TGF- β1) were determined through Western blot analysis in HK-2 cells. Results: In HK-2 cells, purified CRP significantly induced protein release and mRNA expression of IL-6 and TSP-1 in a dose- and time-dependent manner. TGF-β1 protein was overexpressed in HK-2 cells induced by CRP, which cannot be inhibited by IL-6 or TSP-1 antibodies. CRP triggered phosphorylation of p38MAPK and activation of NF-κB-mediated signal transduction. SB203580 (5 μM) and PDTC (50 μM) efficiently suppressed those effects of CRP in HK-2 cells. Conclusions: CRP induces IL-6 and TSP-1 protein release and mRNA expression from HK-2 cells via activation of the p38MAPK and NF-κB signaling pathways and TGF-β1 was highly expressed in HK-2 cells, suggesting that CRP plays an important role in the propagation and prolongation of inflammation in renal fibrosis. Copyright © 2012 S. Karger AG, Basel.


Cui L.,Huazhong Agricultural University | Abbas K.,University of Agriculture at Faisalabad | Yu Y.,Huazhong Agricultural University | Wang W.,Huazhong Agricultural University | And 3 more authors.
Folia Zoologica | Year: 2013

Natural occurrence of pentaploid loach, Misgurnus anguillicaudatus discovered from Liangzi Lake area, Hubei Province, central China, is reported here for the first time. The evidences from karyotyping, DNA content analysis and nuclear volume measurements were described to confirm the pentaploid nature of the identified individual. This individual was phenotypically indistinguishable from its sympatric diploid and tetraploid counterparts. The chromosome number was 5n = 125, the mean erythrocyte nuclear DNA content was 2.62 and 1.25 times of their diploid and tetraploid counterparts, respectively. An origin of such polyploidy form either from genome addition of normal sperm nuclei to unreduced egg and the mating of tetraploid individual and hexaploid individual, respectively, is hypothesized.


Meng X.,CAS Wuhan Institute of Hydrobiology | Meng X.,University of Chinese Academy of Sciences | Jiang X.,CAS Wuhan Institute of Hydrobiology | Xiong X.,State Key Laboratory of Freshwater Ecology and Biotechnology | And 2 more authors.
Limnologica | Year: 2016

The Qinghai Lake area is one of key regions in the Qinghai-Tibet Plateau for supporting a highly specific array of biodiversity. However, little is known about the composition and spatio-temporal patterns of benthic assemblages across this region. Herein, we examined how the community structure and community-environment relationships of macroinvertebrates varied over three consecutive years (2012-2014) across its three distinct water types of the saline main-body (MB) and sub-lakes (SSLs) and the freshwater bodies (FWBs). These waters harbored a poor benthic fauna, with identification of 30 taxa (6 in MB, 6 in SSLs and 23 in FWBs). There were distinct differences of assemblage composition among three water bodies, whereas weak (inter-year) or insignificant (seasons) differences at temporal scales. The CCA models indicated that there were highly naturally-driven environmental-assemblage relationships through time, with constant environmental factors of salinity, water depth and nutrients being the key environmental factors affecting macroinvertebrate variations. The currently overall benthic community composition and structure remains quite stable through years, indicating their suffering less from human activities. These results provide implications for projecting comprehensive benthic biomonitoring and conservation planning for those fragile and under-investigated lakes in the Qinghai-Tibet Plateau. © 2015 Elsevier GmbH.


Dai Z.,Huazhong University of Science and Technology | Dai Z.,CAS Wuhan Institute of Hydrobiology | Wang H.,State Key Laboratory of Freshwater Ecology and Biotechnology | Jin X.,CAS Wuhan Institute of Hydrobiology | And 6 more authors.
American Journal of Physiology - Endocrinology and Metabolism | Year: 2015

Suppressor of cytokine signaling-1a (SOCS1a) is a member of the suppressor of cytokine signaling family, a group of related molecules that mediate the negative regulation of the JAK-STAT pathway. Here, we depleted SOCS1a using the transcription activator-like (TAL) effector nuclease (TALEN) technique to understand its physiological roles in zebrafish. Although elevated levels of JAK-STAT5 activation and erythropoiesis have been observed in socs1a-deficient zebrafish, these animals exhibited normal growth during the early stages. Socs1a-deficient zebrafish began to grow slowly with certain mortalities after 20 days postfertilization (dpf), whereas the heterozygous socs1a-deficient zebrafish exhibited enhanced somatic growth. Decreased adiposity, hepatic steatosis, and insulin resistance were observed in our socs1adeficient adult zebrafish, which is similar to the lipodystrophy phenotypes observed in mammals. Comparative transcriptomic analyses revealed elevated levels of gluconeogenesis, lipolysis, and hypoxiainducible response and decreased activities of lipogenesis and glycolysis in the hepatocytes of socs1a-deflicient adult zebrafish. Evident mitochondrial dysfunction has also been observed in hepatocytes from socs1a-deficient zebrafish. Taken together, our results suggest that the negative regulatory roles of SOCS1a on JAK-STAT5 signaling may be involved in the suppression of the erythropoiesis and growth hormone activities, which was also reflected in the enhanced somatic growth performance observed in the heterozygous socs1a-deficient fish. The differences in the effects caused by SOCS1a depletion on insulin sensitivity, lipid metabolism, and inflammatory responses between zebrafish and mammalian models observed here may reflect differences between the functional mechanisms of SOCS members in terrestrial mammals and aquatic teleosts. © 2015 the American Physiological Society.


PubMed | CAS Wuhan Institute of Hydrobiology, State Key Laboratory of Freshwater Ecology and Biotechnology and Huazhong University of Science and Technology
Type: Journal Article | Journal: American journal of physiology. Endocrinology and metabolism | Year: 2015

Suppressor of cytokine signaling-1a (SOCS1a) is a member of the suppressor of cytokine signaling family, a group of related molecules that mediate the negative regulation of the JAK-STAT pathway. Here, we depleted SOCS1a using the transcription activator-like (TAL) effector nuclease (TALEN) technique to understand its physiological roles in zebrafish. Although elevated levels of JAK-STAT5 activation and erythropoiesis have been observed in socs1a-deficient zebrafish, these animals exhibited normal growth during the early stages. Socs1a-deficient zebrafish began to grow slowly with certain mortalities after 20 days postfertilization (dpf), whereas the heterozygous socs1a-deficient zebrafish exhibited enhanced somatic growth. Decreased adiposity, hepatic steatosis, and insulin resistance were observed in our socs1a-deficient adult zebrafish, which is similar to the lipodystrophy phenotypes observed in mammals. Comparative transcriptomic analyses revealed elevated levels of gluconeogenesis, lipolysis, and hypoxia-inducible response and decreased activities of lipogenesis and glycolysis in the hepatocytes of socs1a-deflicient adult zebrafish. Evident mitochondrial dysfunction has also been observed in hepatocytes from socs1a-deficient zebrafish. Taken together, our results suggest that the negative regulatory roles of SOCS1a on JAK-STAT5 signaling may be involved in the suppression of the erythropoiesis and growth hormone activities, which was also reflected in the enhanced somatic growth performance observed in the heterozygous socs1a-deficient fish. The differences in the effects caused by SOCS1a depletion on insulin sensitivity, lipid metabolism, and inflammatory responses between zebrafish and mammalian models observed here may reflect differences between the functional mechanisms of SOCS members in terrestrial mammals and aquatic teleosts.

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