AQUACULTURE
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2016
·
IF 1.893
Ningning Liu,Shanshan Zhang,Weiwei Zhang,Chenghua Li
Recently, the use of probiotics as an alternative strategy to control bacterial diseases in aquaculture has garnered much attention due to the merits of environmental friendliness. In this study, a bacterium identified as Vibrio sp. V33 was isolated from healthy sepia and was determined to have strong antagonistic activity towards the pathogenic isolate Vibrio splendidus Vs using the disk diffusion method. The antagonistic substance was secreted into the supernatant and was thermo-stable. The antagonistic activity of Vibrio sp. V33 may be attributed to its higher ability to compete for iron than that of V . splendidus Vs, as deduced from siderophore quantification using the CAS method. Number of colony counts from seawater and Apostichopus japonicus infection experiments showed that Vibrio sp. V33 significantly decreased the quantity of V . splendidus Vs in natural seawater and promoted the survival rate of A . japonicus infected by V . splendidus , with a relative percentage survival of 43% under the current conditions. Our findings suggest that V33 could be potentially used as potential bacterial antagonist for controlling V . splendidus infections in sea cucumber aquaculture. Statement of relevance It might protect A . japonicus from V . splendidus infection.
研究领域:
水产养殖学
·
微生物学
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DOI
高影响因子
APPLIED MICROBIOLOGY AND BIOTECHNOLOGY
·
2016
·Vol. 101
·期 8
·3371-3378
·
IF 3.376
Zhang Shanshan,Liu Ningning,Liang Weikang,Han Qingxi,Zhang Weiwei,Li Chenghua
In the present study, the effects of an environmental friendly natural reagent coumarin, on the growth and potential virulence factors, as well as its ability to interfere the infection of Vibrio splendidus (Vs), were determined. Coumarin showed no effects on the maximal growth of Vs, and biofilm formation of Vs, while it significantly decreased protease activity and hemolytic activity by 43 and 80%, respectively. Correspondingly, coumarin exhibited an obviously protective effect, with a relative percent survival of 60% upon Apostichopus japonicus from infection by Vs. To preliminarily investigate the mechanism underlining the inhibitory effects, regulation of genes Vsm and Vsh respectively related to protease activity and hemolytic activity by supernatant and supernatant extract containing acyl-homoserine lactones (AHLs) and coumarin was determined. Cell-free supernatant from higher density and its ethyl acetate extract containing AHL signal molecules could respectively upregulate the mRNA level of Vsm by 17.4- and 2.3-fold and Vsh by 7.2- and 5.0-fold, when Vs was at lower cell density. However, coumarin could reduce the stimulatory effects of both the supernatant and its ethyl acetate extract. Combining all the results in our study, it was suggested that coumarin could be considered as an alternative to be used for controlling infection of Vs, downregulating the expression of potential virulence factors through interfering the AHL-mediated pathways.
研究领域:
微生物学
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海洋生物学
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分子生物学
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DOI
PubMed
高影响因子
Current Research in Microbial Sciences
·
2025
·
IF 5.8
Zhi Wu,Yina Shao,Shanshan Zhang,Chenghua Li
Vibrio splendidus AJ01 is the primary pathogen of Apostichopus japonicus , resulting in huge economic losses. In the present study, we found that 5-iodoindole exhibits a remarkable protective effect on A. japonicus , the survival rate of which can be improved to 93.75%. To explore the impact of 5-iodoindole on V. splendidus AJ01, bacterial growth and virulence factors were determined. Results showed that 5-iodoindole significantly decreased swimming motility, hemolytic activity and protease activity but had minimal effect on the overall growth of the bacterium. Furthermore, a differentially expressed protein was downregulated and identified as elongation factor thermo unstable protein (EF-Tu) via SDS-PAGE combined with LC-MS/MS. Moreover, 5-iodoindole had impact on a large number of genes at RNA level, such as genes related to two-component system, ABC transporters, flagella, and chemotaxis. In addition, 20 µM 5-iodoindole could upregulated the mRNA level of immune related genes in A. japonicus , including IL-17, VEGF and MMP1. Our results indicated 5-iodoindole protect A. japonicus through a two-pronged approach: not only inhibiting bacterial virulence but also enhancing the host's immunity. This not only addresses the limitations of traditional indole but also provides a green alternative to antibiotics for protecting A. japonicus from infections caused by V. splendidus AJ01.
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产品关联
DOI
PubMed
高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2024
·
IF 7.7
Yangxi Xiang,Yue Shi,Lianlian Sun,Weikang Liang,Kaiyu Chen,Chenghua Li
Pattern recognition receptors (PRRs) mediate the innate immune responses and play a crucial role in host defense against pathogen infections. Apextrin C-terminal (ApeC)-containing proteins (ACPs), a newly discovered class of PRRs specific to invertebrates, recognize pathogens through their ApeC domain as intracellular or extracellular effectors. However, the other immunological functions of ACPs remain unclear. In this study, a membrane-localized ACP receptor was identified in the sea cucumber Apostichopus japonicus (denoted as AjACP1). The ApeC domain of AjACP1, which was located outside of its cell membrane, exhibited the capability to recognize and aggregate Vibrio splendidus . AjACP1 was upregulated upon V. splendidus infection, internalizing into the cytoplasm of coelomocytes. AjACP1 overexpression enhanced the phagocytic activity of coelomocytes against V. splendidus , while knockdown of AjACP1 by RNA interfere inhibited coelomocyte endocytosis. Inhibitor experiments indicated that AjACP1 regulated coelomocyte phagocytosis through the actin-dependent endocytic signaling pathway. Further investigation revealed that AjACP1 interacted with the subunit of the actin-related protein 2/3 complex ARPC2, promoting F-actin polymerization and cytoskeletal rearrangement and thereby affecting the coelomocyte phagocytosis of V. splendidus via the actin-dependent endocytic signaling pathway. As a novel membrane PRR, AjACP1 mediates the recognition and phagocytic activity of coelomocytes against V. splendidus through the AjACP1-ARPC2-F-actin polymerization and cytoskeletal rearrangement pathway.
研究领域:
免疫学
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海洋生物学
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分子生物学
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DOI
高影响因子
AQUACULTURE
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2026
·
IF 4.4
Tianfen Liang,Xinyue Ma,Zhimeng Lv,Yina Shao,Weikang Liang,Chenghua Li
To establish a successful infection, bacteria have evolved highly efficient strategies that enable them to enter host cells and disrupt host transport pathways, thereby creating a favorable intracellular niche for survival. With the occurrence of the phagocytic process, Vibrio cholerae releases the effector VgrG-1 of its type VI secretion system (T6SS), which disrupts the host actin cytoskeleton. It is precisely because of this destruction that a bystander protection effect for extracellular bacterial communities can be established. However, VgrG proteins exist in multiple isoforms. Those lacking additional effector domains are generally considered to function primarily as structural components for T6SS assembly, and their roles in pathogenesis are poorly defined. In this study, we characterized a gene from Vibrio splendidus with a cDNA sequence of 1983 base pairs, designated as the valine-glycine repeat protein G ( VsVgrG ) without actin-crosslinking domain. The expression analysis revealed that both mRNA and protein levels of VsVgrG were significantly enhanced following stimulation with Apostichopus japonicus coelomic fluid. Flow cytometry and bacterial plate count assays demonstrated that VsVgrG knockout significantly reduced V. splendidus internalization. Furthermore, immunofluorescence analysis revealed that, compared to cells treated with the Δ VsVgrG mutant, the actin cytoskeleton of sea cucumber coelomocytes exhibited significant dissociation following infection by the wild-type strain. Mechanistically, we identified A. japonicus IQ Motif Containing GTPase Activating Protein 1 (AjIQGAP1) as a direct host binding partner of VsVgrG. Combined overexpression and inhibitor treatment, we demonstrated that VsVgrG promotes pathogen internalization by targeting AjIQGAP1 via actin-dependent endocytosis pathway. Our findings reveal a potential mechanism for V. splendidus internalization and advance our understanding of universal biological mechanisms in pathogen-host interactions.
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DOI
高影响因子
PLoS Pathogens
·
2023
·Vol. 19
·期 5
·e1011419
·
IF 6.7
Fa Dai,Ming Guo,Yina Shao,Chenghua Li
We previously demonstrated that the flagellin of intracellular Vibrio splendidus AJ01 could be specifically identified by tropomodulin (Tmod) and further mediate p53-dependent coelomocyte apoptosis in the sea cucumber Apostichopus japonicus . In higher animals, Tmod serves as a regulator in stabilizing the actin cytoskeleton. However, the mechanism on how AJ01 breaks the AjTmod-stabilized cytoskeleton for internalization remains unclear. Here, we identified a novel AJ01 Type III secretion system (T3SS) effector of leucine-rich repeat-containing serine/threonine-protein kinase (STPKLRR) with five LRR domains and a serine/threonine kinase (STYKc) domain, which could specifically interact with tropomodulin domain of AjTmod. Furthermore, we found that STPKLRR directly phosphorylated AjTmod at serine 52 (S52) to reduce the binding stability between AjTmod and actin. After AjTmod dissociated from actin, the F-actin/G-actin ratio decreased to induce cytoskeletal rearrangement, which in turn promoted the internalization of AJ01. The STPKLRR knocked out strain could not phosphorylated AjTmod and displayed lower internalization capacity and pathogenic effect compared to AJ01. Overall, we demonstrated for the first time that the T3SS effector STPKLRR with kinase activity was a novel virulence factor in Vibrio and mediated self-internalization by targeting host AjTmod phosphorylation dependent cytoskeleton rearrangement, which provided a candidate target to control AJ01 infection in practice.
Vibrio splendidus AJ01 is the major pathogen for skin ulcer syndrome (SUS) in Apostichopus japonicus , nevertheless, its pathogenic mechanism remains unknown. Eukaryotic-like factors play a crucial role in bacterial virulence by targeting hosts. Despite their significance, the eukaryotic factors in Vibrio splendidus have not been studied, and the mechanism by which they interact with the host remains unclear. In this study, we found an eukaryotic-like factor STPKLRR of V . splendidus for the first time. Furthermore, STPKLRR, selected by T3SS, can phosphorylate Tmod at S52, dissociate the Tmod/actin complex, cause cytoskeleton rearrangement and promote the internalization of V . splendidus . Our findings provide insight into the mechanisms underlying the internalization of V . splendidus and advance our knowledge of the general biology of pathogen-host interactions.
研究领域:
微生物学
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分子生物学
·
病理学
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免疫学
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产品关联
DOI
PubMed
高影响因子
JOURNAL OF INVERTEBRATE PATHOLOGY
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2018
·
IF 2.511
Tongxiang Song,Huijie Liu,Tengteng Lv,Xuelin Zhao,Yina Shao,Qingxi Han,Chenghua Li,Weiwei Zhang
Under low iron bioavailability environment, many bacteria acquire iron for growth and survival through siderophore-mediated iron acquisition systems. However, until now, little research on the growth, siderophore production and siderophore receptors of Vibrio splendidus Vs under iron limited conditions has been reported. In our present study, V. splendidus Vs could survive in media supplemented with 160 µM 2,2′-dipyridyl (DIP), but 74.5% of the growth was suppressed at 48 h, while the siderophore production of V. splendidus Vs increased by 35.9%. As the OD 600 of V. splendidus Vs decreased when the concentration of DIP was increased from 40 to 80 µM, the siderophore production of V. splendidus Vs increased from 34.0% to 43.4% at 24 h, and it was further determined to be a hydroxamate siderophore. To explore the potential siderophore receptors anchored on the outer membrane of V. splendidus Vs, outer membrane proteins from cells grown with and without 80 µM DIP were extracted and the differentially expressed proteins were identified by SDS-PAGE and MALDI-TOF/TOF MS. Five proteins, aerobactin siderophore receptor IutA, enterobactin receptor protein FepA, ATP synthase subunit A, ATP synthase subunit B and the ATP synthase F0F1 subunit beta were identified. Real-time reverse transcriptase PCR showed that mRNA levels of iutA , fepA, atpA , atpB and atpβ - F0F1 were upregulated 271.5-, 15.1-, 1.1-, 2.5- and 67.9-fold respectively, after 6 h in cells treated with 80 µM DIP. In addition, the promoters of the siderophore receptor genes of iutA and fepA had apparent ferric uptake regulator (Fur) binding sites. Combined with the simultaneous production of both the hydroxamate siderophore and its corresponding aerobactin siderophore receptor IutA, these results suggested that there might be a hydroxamate siderophore-IutA mediated iron uptake pathway in V. splendidus Vs.
研究领域:
微生物学
·
海洋生物学
·
分子生物学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
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