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Shi L, Zhao L, Li Q, Huang L, Qin Y, Zhuang Z, Wang X, Huang H, Zhang J, Zhang J, Yan Q. Role of the Pseudomonas plecoglossicida fliL gene in immune response of infected hybrid groupers (Epinephelus fuscoguttatus ♀ × Epinephelus lanceolatus ♂). Front Immunol 2024; 15:1415744. [PMID: 39026675 PMCID: PMC11254626 DOI: 10.3389/fimmu.2024.1415744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2024] [Accepted: 06/19/2024] [Indexed: 07/20/2024] Open
Abstract
Pseudomonas plecoglossicida, a gram-negative bacterium, is the main pathogen of visceral white-point disease in marine fish, responsible for substantial economic losses in the aquaculture industry. The FliL protein, involved in torque production of the bacterial flagella motor, is essential for the pathogenicity of a variety of bacteria. In the current study, the fliL gene deletion strain (ΔfliL), fliL gene complement strain (C-ΔfliL), and wild-type strain (NZBD9) were compared to explore the influence of the fliL gene on P. plecoglossicida pathogenicity and its role in host immune response. Results showed that fliL gene deletion increased the survival rate (50%) and reduced white spot disease progression in the hybrid groupers. Moreover, compared to the NZBD9 strain, the ΔfliL strain was consistently associated with lower bacterial loads in the grouper spleen, head kidney, liver, and intestine, coupled with reduced tissue damage. Transcriptomic analysis identified 2 238 differentially expressed genes (DEGs) in the spleens of fish infected with the ΔfliL strain compared to the NZBD9 strain. Based on Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis, the DEGs were significantly enriched in seven immune system-associated pathways and three signaling molecule and interaction pathways. Upon infection with the ΔfliL strain, the toll-like receptor (TLR) signaling pathway was activated in the hybrid groupers, leading to the activation of transcription factors (NF-κB and AP1) and cytokines. The expression levels of proinflammatory cytokine-related genes IL-1β, IL-12B, and IL-6 and chemokine-related genes CXCL9, CXCL10, and CCL4 were significantly up-regulated. In conclusion, the fliL gene markedly influenced the pathogenicity of P. plecoglossicida infection in the hybrid groupers. Notably, deletion of fliL gene in P. plecoglossicida induced a robust immune response in the groupers, promoting defense against and elimination of pathogens via an inflammatory response involving multiple cytokines.
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Affiliation(s)
- Lian Shi
- Fisheries College, Jimei University, Xiamen, China
| | - Lingmin Zhao
- Fisheries College, Jimei University, Xiamen, China
| | - Qi Li
- Fisheries College, Jimei University, Xiamen, China
| | - Lixing Huang
- Fisheries College, Jimei University, Xiamen, China
| | - Yingxue Qin
- Fisheries College, Jimei University, Xiamen, China
| | - Zhixia Zhuang
- College of Environment and Public Health, Xiamen Huaxia University, Xiamen, China
| | - Xiaoru Wang
- College of Environment and Public Health, Xiamen Huaxia University, Xiamen, China
| | - Huabin Huang
- College of Environment and Public Health, Xiamen Huaxia University, Xiamen, China
| | - Jiaonan Zhang
- Key Laboratory of Special Aquatic Feed for Fujian, Fujian Tianma Technology Company Limited, Fuzhou, China
| | - Jiaolin Zhang
- Key Laboratory of Special Aquatic Feed for Fujian, Fujian Tianma Technology Company Limited, Fuzhou, China
| | - Qingpi Yan
- Fisheries College, Jimei University, Xiamen, China
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Mao Z, Li S, Li Y, Jia T. The bacterial pathogen Pseudomonas plecoglossicida, its epidemiology, virulence factors, vaccine development, and host-pathogen interactions. JOURNAL OF AQUATIC ANIMAL HEALTH 2024; 36:181-191. [PMID: 38402543 DOI: 10.1002/aah.10215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 12/10/2023] [Accepted: 01/05/2024] [Indexed: 02/26/2024]
Abstract
OBJECTIVE Pseudomoans plecoglossicida has been identified as a fish pathogen since 2000 and has caused serious infections in cultured Large Yellow Croakers Larimiththys crocea in coastal eastern China during recent years. METHODS Published literatures of this pathogen have been reviewed. RESULT Several strains with high genomic similarity have been isolated and identified; the bacteria induce natural infection at lower water temperatures (12.0-25.5°C) and induce numerous granulomas and nodules in the visceral organs of croakers. Researchers have investigated the epidemiology of P. plecoglossicida infection, identified major virulence factors, searched for pathogenic genes, analyzed host-pathogen interactions, and endeavored to develop efficient vaccines. CONCLUSION This paper provides an overview of these research advances to elucidate the virulence mechanisms of the pathogen and to promote vaccine development against infection.
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Affiliation(s)
- Zhijuan Mao
- Biological and Environmental College, Zhejiang Wanli University, Ningbo, China
| | - Shanshan Li
- Biological and Environmental College, Zhejiang Wanli University, Ningbo, China
| | - Yiying Li
- Biological and Environmental College, Zhejiang Wanli University, Ningbo, China
| | - Tingting Jia
- Biological and Environmental College, Zhejiang Wanli University, Ningbo, China
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Yang D, Zhao L, Li Q, Huang L, Qin Y, Wang P, Zhu C, Yan Q. The involvement of the T6SS vgrG gene in the pathogenicity of Pseudomonas plecoglossicida. JOURNAL OF FISH DISEASES 2023; 46:1097-1108. [PMID: 37401135 DOI: 10.1111/jfd.13829] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 06/19/2023] [Accepted: 06/21/2023] [Indexed: 07/05/2023]
Abstract
Pseudomonas plecoglossicida, the causative agent of white spot disease of large yellow croaker, has caused serious economic losses to the aquaculture industry. The type VI secretion system (T6SS) is a significant virulence system widely distributed among Gram-negative bacteria. VgrG, a structural and core component of T6SS, is crucial to the function of T6SS. To explore the biological profiles mediated by vgrG gene and its effects on the pathogenicity of P. plecoglossicida, the vgrG gene deletion (ΔvgrG) strain and complementary (C-ΔvgrG) strain were constructed and the differences in pathogenicity and virulence-related characteristics between different strains were analysed. The results showed that vgrG gene deletion significantly affected the virulence-related characteristics of P. plecoglossicida, including chemotaxis, adhesion, and biofilm formation. In addition, the LD50 of ΔvgrG strain was nearly 50-fold higher than that of the NZBD9 strain. Transcriptome data analysis suggested that the vgrG gene may affect the virulence of P. plecoglossicida by regulating the quorum sensing pathway to inhibit the secretion of virulence factors and affect biofilm formation. Besides, deletion of the vgrG gene may reduce bacterial pathogenicity by affecting bacterial signal transduction processes and the ability to adapt to chemotactic substances.
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Affiliation(s)
- Dou Yang
- Fisheries College, Jimei University, Xiamen, China
| | - Lingmin Zhao
- Fisheries College, Jimei University, Xiamen, China
| | - Qi Li
- Fisheries College, Jimei University, Xiamen, China
| | - Lixing Huang
- Fisheries College, Jimei University, Xiamen, China
| | - Yingxue Qin
- Fisheries College, Jimei University, Xiamen, China
| | - Pan Wang
- Key Laboratory of Aquatic Functional Feed and Environmental Regulation of Fujian Province, Fujian Dabeinong Aquatic Sci. & Tech. Co., Ltd, Zhangzhou, China
| | - Chuanzhong Zhu
- Key Laboratory of Aquatic Functional Feed and Environmental Regulation of Fujian Province, Fujian Dabeinong Aquatic Sci. & Tech. Co., Ltd, Zhangzhou, China
| | - Qingpi Yan
- Fisheries College, Jimei University, Xiamen, China
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Ji X, Han Y, Wu Y, Liang B, Zheng J, Ma S, Li C, Xu H, Guo S. Synthesis of nano-Fe 3O 4/ZnO composites with enhanced antibacterial properties and plant growth promotion via one-pot reaction. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:87016-87027. [PMID: 37420151 DOI: 10.1007/s11356-023-28534-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2023] [Accepted: 06/28/2023] [Indexed: 07/09/2023]
Abstract
Bordeaux mixture is commonly used in agricultural production due to its certain antibacterial activity. However, it has been observed to promote plant growth at a slow pace. Therefore, it is crucial to explore an effective antibacterial agent that can enhance the antibacterial activity and promote plant growth in commercially available Bordeaux mixture, which can significantly contribute to the development of the agricultural economy. The investigation into inorganic agents with both bacteriostatic and plant-promoting properties has a broad application potential in agriculture. Fe3O4/ZnO (FZ) composites were synthesized from FeCl3, ZnCl2, and NaAc in a "one-pot approach" and analyzed using transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and a vibrating sample magnetometer (VSM). To investigate the antibacterial activity and mechanism of FZ nanocomposites, Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus) were used as model bacteria, and human mammary epithelial cells and model plant mung bean were used as targets to study the effects of FZ on human and plant growth. The results revealed that at 300 µg/mL for 80 min, the antibacterial efficacy of FZ composites was 99.8% against E. coli, which was 20% greater than that of Bordeaux liquid (FC), and 99.9% against S. aureus, which was 28.6% higher than that of FC. The inhibitory mechanism demonstrated that the substance could efficiently damage the bacterial cell wall of a concentration of 300 µg/mL. The IC50 of the material to human mammary epithelial cells was 49.518 µg/mL, and it also increased mung bean germination, root growth, and chlorophyll content, indicating that the application performance was 1.5 times better than that of FC. Its exceptional performance can be used to treat agricultural diseases.
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Affiliation(s)
- Xiaohui Ji
- Shaanxi Key Laboratory of Catalysis, School of Chemical & Environment Science, Shaanxi University of Technology, Hanzhong, Shaanxi, 723001, People's Republic of China
- State Key Laboratory of Qinba Bio-Resource and Ecological Environment, Shaanxi University of Technology, Hanzhong, Shaanxi, 723001, People's Republic of China
| | - Yuanyuan Han
- Shaanxi Key Laboratory of Catalysis, School of Chemical & Environment Science, Shaanxi University of Technology, Hanzhong, Shaanxi, 723001, People's Republic of China
- State Key Laboratory of Qinba Bio-Resource and Ecological Environment, Shaanxi University of Technology, Hanzhong, Shaanxi, 723001, People's Republic of China
| | - Yinghua Wu
- Shaanxi Key Laboratory of Catalysis, School of Chemical & Environment Science, Shaanxi University of Technology, Hanzhong, Shaanxi, 723001, People's Republic of China
- State Key Laboratory of Qinba Bio-Resource and Ecological Environment, Shaanxi University of Technology, Hanzhong, Shaanxi, 723001, People's Republic of China
| | - Ben Liang
- Shaanxi Key Laboratory of Catalysis, School of Chemical & Environment Science, Shaanxi University of Technology, Hanzhong, Shaanxi, 723001, People's Republic of China
- State Key Laboratory of Qinba Bio-Resource and Ecological Environment, Shaanxi University of Technology, Hanzhong, Shaanxi, 723001, People's Republic of China
| | - Jinli Zheng
- Shaanxi Key Laboratory of Catalysis, School of Chemical & Environment Science, Shaanxi University of Technology, Hanzhong, Shaanxi, 723001, People's Republic of China
- State Key Laboratory of Qinba Bio-Resource and Ecological Environment, Shaanxi University of Technology, Hanzhong, Shaanxi, 723001, People's Republic of China
| | - Shuting Ma
- Shaanxi Key Laboratory of Catalysis, School of Chemical & Environment Science, Shaanxi University of Technology, Hanzhong, Shaanxi, 723001, People's Republic of China
- State Key Laboratory of Qinba Bio-Resource and Ecological Environment, Shaanxi University of Technology, Hanzhong, Shaanxi, 723001, People's Republic of China
| | - Chen Li
- Shaanxi Key Laboratory of Catalysis, School of Chemical & Environment Science, Shaanxi University of Technology, Hanzhong, Shaanxi, 723001, People's Republic of China
- State Key Laboratory of Qinba Bio-Resource and Ecological Environment, Shaanxi University of Technology, Hanzhong, Shaanxi, 723001, People's Republic of China
| | - Haitao Xu
- Shaanxi Key Laboratory of Catalysis, School of Chemical & Environment Science, Shaanxi University of Technology, Hanzhong, Shaanxi, 723001, People's Republic of China
- State Key Laboratory of Qinba Bio-Resource and Ecological Environment, Shaanxi University of Technology, Hanzhong, Shaanxi, 723001, People's Republic of China
| | - Shaobo Guo
- Shaanxi Key Laboratory of Catalysis, School of Chemical & Environment Science, Shaanxi University of Technology, Hanzhong, Shaanxi, 723001, People's Republic of China.
- State Key Laboratory of Qinba Bio-Resource and Ecological Environment, Shaanxi University of Technology, Hanzhong, Shaanxi, 723001, People's Republic of China.
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Wang J, Xiu L, Qiao Y, Zhang Y. Virulence regulation of Zn2+ uptake system znuABC on mesophilic Aeromonas salmonicida SRW-OG1. Front Vet Sci 2023; 10:1172123. [PMID: 37065252 PMCID: PMC10090552 DOI: 10.3389/fvets.2023.1172123] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Accepted: 03/14/2023] [Indexed: 03/31/2023] Open
Abstract
Psychrophilic Aeromonas salmonicida could not grow above 25°C and therefore thought unable to infect mammals and humans. In our previous study, a mesophilic A. salmonicida SRW-OG1 was isolated from Epinephelus coioides with furunculosis. Through the analysis of preliminary RNA-seq, it was found that the Zn2+ uptake related genes znuA, znuB and znuC might be involved in the virulence regulation of A. salmonicida SRW-OG1. Therefore, the purpose of this study was to explore the effect of znuABC silencing on the virulence regulation of A. salmonicida SRW-OG1. The results showed that the growth of the znuA-RNAi, znuB-RNAi, and znuC-RNAi strains was severely restricted under the Fe2+ starvation, but surprisingly there was no significant difference under the Zn2+ restriction. In the absence of Zn2+ and Fe2+, the expression level of znuABC was significantly increased. The motility, biofilm formation, adhesion and hemolysis of the znuA-RNAi, znuB-RNAi, and znuC-RNAi strains were significantly reduced. We also detected the expression of znuABC under different growth periods, temperatures, pH, as well as Cu2+ and Pb2+ stresses. The results showed that znuABC was significantly up-regulated in the logarithmic phase and the decline phase of A. salmonicida. Interestingly, the trend of expression levels of the znuABC at 18, 28, and 37°C was reversed to another Zn2+ uptake related gene zupT. Taken together, these indicated that the znuABC was necessary for A. salmonicida SRW-OG1 pathogenicity and environmental adaptability, and was cross regulated by iron starvation, but it was not irreplaceable for A. salmonicida SRW-OG1 Zn2+ uptake in the host.
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Affiliation(s)
- Jiajia Wang
- Fisheries College, Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Jimei University, Xiamen, Fujian, China
| | - Lijun Xiu
- Fisheries College, Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Jimei University, Xiamen, Fujian, China
| | - Ying Qiao
- Fourth Institute of Oceanography, Key Laboratory of Tropical Marine Ecosystem and Bioresource, Ministry of Natural Resources, Beihai, China
| | - Youyu Zhang
- Institute of Electromagnetics and Acoustics, School of Electronic Science and Engineering, Xiamen University, Xiamen, China
- *Correspondence: Youyu Zhang
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Cai H, Yu J, Qiao Y, Ma Y, Zheng J, Lin M, Yan Q, Huang L. Effect of the Type VI Secretion System Secreted Protein Hcp on the Virulence of Aeromonas salmonicida. Microorganisms 2022; 10:microorganisms10122307. [PMID: 36557560 PMCID: PMC9784854 DOI: 10.3390/microorganisms10122307] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 11/16/2022] [Accepted: 11/19/2022] [Indexed: 11/23/2022] Open
Abstract
Aeromonas salmonicida, a psychrophilic bacterial pathogen, is widely distributed in marine freshwater, causing serious economic losses to major salmon farming areas in the world. At present, it is still one of the most important pathogens threatening salmon farming. Hcp (haemolysin-coregulated protein) is an effector protein in the type-VI secretion system (T6SS), which is secreted by T6SS and functions as its structural component. The results of our previous genomic sequencing showed that hcp existed in the mesophilic A. salmonicida SRW-OG1 isolated from naturally infected Epinephelus coioides. To further explore the role of Hcp in A. salmonicida SRW-OG1, we constructed an hcp-RNAi strain and verified its effect on the virulence of A. salmonicida. The results showed that compared with the wild strain, the hcp-RNAi strain suffered from different degrees of decreased adhesion, growth, biofilm formation, extracellular product secretion, and virulence. It was suggested that hcp may be an important virulence gene of A. salmonicida SRW-OG1.
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Affiliation(s)
- Hongyan Cai
- Key Laboratory of Healthy Mariculture for the East China Sea, Fisheries College, Ministry of Agriculture, Jimei University, Xiamen 361021, China
| | - Jiaying Yu
- Key Laboratory of Healthy Mariculture for the East China Sea, Fisheries College, Ministry of Agriculture, Jimei University, Xiamen 361021, China
| | - Ying Qiao
- Fourth Institute of Oceanography, Ministry of Natural Resources, No. 26, New Century Avenue, Beihai 536000, China
| | - Ying Ma
- Key Laboratory of Healthy Mariculture for the East China Sea, Fisheries College, Ministry of Agriculture, Jimei University, Xiamen 361021, China
| | - Jiang Zheng
- Key Laboratory of Healthy Mariculture for the East China Sea, Fisheries College, Ministry of Agriculture, Jimei University, Xiamen 361021, China
| | - Mao Lin
- Key Laboratory of Healthy Mariculture for the East China Sea, Fisheries College, Ministry of Agriculture, Jimei University, Xiamen 361021, China
| | - Qingpi Yan
- Key Laboratory of Healthy Mariculture for the East China Sea, Fisheries College, Ministry of Agriculture, Jimei University, Xiamen 361021, China
- Correspondence: (Q.Y.); (L.H.)
| | - Lixing Huang
- Key Laboratory of Healthy Mariculture for the East China Sea, Fisheries College, Ministry of Agriculture, Jimei University, Xiamen 361021, China
- Correspondence: (Q.Y.); (L.H.)
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Yuan B, Zhao LM, Zhuang ZX, Wang XR, Fu Q, Huang HB, Huang LX, Qin YX, Yan QP. Transcriptomic and metabolomic insights into the role of the flgK gene in the pathogenicity of Pseudomonas plecoglossicida to orange-spotted grouper ( Epinephelus coioides). Zool Res 2022; 43:952-965. [PMID: 36208122 PMCID: PMC9700492 DOI: 10.24272/j.issn.2095-8137.2022.216] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Accepted: 09/26/2022] [Indexed: 07/24/2023] Open
Abstract
Pseudomonas plecoglossicida is the pathogen responsible for visceral white spot disease in large yellow croaker (Larimichthys crocea) and orange-spotted grouper (Epinephelus coioides). Previously, RNA sequencing showed that P. plecoglossicida flgK gene expression was significantly up-regulated in orange-spotted grouper spleens during infection. To explore the role of flgK in P. plecoglossicida pathogenicity, RNA interference (RNAi) was performed to silence the P. plecoglossicida flgK gene, and the mutant (flgK-RNAi strain) with the best silencing efficiency (89.40%) was chosen for further study. Results showed that flgK gene silencing significantly attenuated P. plecoglossicida motility, adhesion, and biofilm formation. Compared to those fish infected with the wild-type strain of P. plecoglossicida, orange-spotted grouper infected with the flgK-RNAi strain showed a 55% increase in the survival rate and a one-day delay in time of first death, with fewer pathogens in the spleen and fewer white spots on the spleen surface. RNAi of flgK significantly affected the transcriptome and metabolome of the spleen in infected orange-spotted grouper. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis showed that the C-type lectin receptor signaling pathway was the most significantly changed immune-related pathway and the mitogen-activated protein kinase (MAPK) signaling pathway was related to multiple immune-related pathways. Furthermore, arginine biosynthesis and glycerophospholipid metabolism were the most significantly changed metabolism-related pathways. These findings suggest that flgK is a virulence gene of P. plecoglossicida. Furthermore, flgK appears to be involved in the regulation of motility, adhesion, and biofilm formation in P. plecoglossicida, as well as in the regulation of inflammatory and immune responses of orange-spotted grouper to P. plecoglossicida infection.
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Affiliation(s)
- Biao Yuan
- Fisheries College, Jimei University, Xiamen, Fujian 361021, China
| | - Ling-Min Zhao
- Fisheries College, Jimei University, Xiamen, Fujian 361021, China
| | - Zhi-Xia Zhuang
- College of Environment and Public Health, Xiamen Huaxia University, Xiamen, Fujian 361024, China
| | - Xiao-Ru Wang
- College of Environment and Public Health, Xiamen Huaxia University, Xiamen, Fujian 361024, China
| | - Qi Fu
- College of Environment and Public Health, Xiamen Huaxia University, Xiamen, Fujian 361024, China
| | - Hua-Bin Huang
- College of Environment and Public Health, Xiamen Huaxia University, Xiamen, Fujian 361024, China
| | - Li-Xing Huang
- Fisheries College, Jimei University, Xiamen, Fujian 361021, China
| | - Ying-Xue Qin
- Fisheries College, Jimei University, Xiamen, Fujian 361021, China
| | - Qing-Pi Yan
- Fisheries College, Jimei University, Xiamen, Fujian 361021, China. E-mail:
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Nie W, Chen X, Tang Y, Xu N, Zhang H. Potential dsRNAs can be delivered to aquatic for defense pathogens. Front Bioeng Biotechnol 2022; 10:1066799. [PMID: 36466329 PMCID: PMC9712207 DOI: 10.3389/fbioe.2022.1066799] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Accepted: 11/03/2022] [Indexed: 10/29/2023] Open
Abstract
The use of antibiotics to facilitate resistance to pathogens in aquatic animals is a traditional method of pathogen control that is harmful to the environment and human health. RNAi is an emerging technology in which homologous small RNA molecules target specific genes for degradation, and it has already shown success in laboratory experiments. However, further research is needed before it can be applied in aquafarms. Many laboratories inject the dsRNA into aquatic animals for RNAi, which is obviously impractical and very time consuming in aquafarms. Therefore, to enable the use of RNAi on a large scale, the methods used to prepare dsRNA need to be continuously in order to be fast and efficient. At the same time, it is necessary to consider the issue of biological safety. This review summarizes the key harmful genes associated with aquatic pathogens (viruses, bacteria, and parasites) and provides potential targets for the preparation of dsRNA; it also lists some current examples where RNAi technology is used to control aquatic species, as well as how to deliver dsRNA to the target hydrobiont.
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Affiliation(s)
| | | | | | | | - Hao Zhang
- Key Laboratory of Marine Biotechnology of Zhejiang Province, School of Marine Sciences, Ningbo University, Ningbo, China
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Enhanced Hemolytic Activity of Mesophilic Aeromonas salmonicida SRW-OG1 Is Brought about by Elevated Temperatures. Microorganisms 2022; 10:microorganisms10102033. [PMID: 36296309 PMCID: PMC9609485 DOI: 10.3390/microorganisms10102033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 10/04/2022] [Accepted: 10/12/2022] [Indexed: 11/17/2022] Open
Abstract
Aeromonas salmonicida is a well-known cold-water pathogenic bacterium. Previously, we reported the first isolation of pathogenic A. salmonicida from diseased Epinephelus coioides, a kind of warm-water fish, and it was proved to be a putative mesophilic strain with potent pathogenicity to humans. In order to investigate the mechanisms underlying mesophilic growth ability and virulence, the transcriptome of A. salmonicida SRW-OG1 at 18, 28, and 37 °C was analyzed. The transcriptome of A. salmonicida SRW-OG1 at different temperatures showed a clear separation boundary, which might provide valuable information for the temperature adaptation and virulence regulation of A. salmonicida SRW-OG1. Interestingly, aerA and hlyA, the hemolytic genes encoding aerolysin and hemolysin, were found to be significantly up-regulated at 28 and 37 °C. Since aerolysin and hemolysin are the most well-known and -characterized virulence factors of pathogenic Aeromonas strains, the induction of aerA and hlyA was associated with the mesophilic virulence. Further study proved that the extracellular products (ECPs) purchased from A. salmonicida SRW-OG1 cultured at 28 and 37 °C showed elevated hemolytic activity and virulence than those at 18 °C. Moreover, the silence of aerA and hlyA led to significantly decreased hemolysis and virulence. Taken together, our results revealed that the mesophilic virulence of A. salmonicida SRW-OG1 might be due to the enhanced expression of aerA and hlyA induced by elevated temperatures.
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He R, Wang J, Lin M, Tian J, Wu B, Tan X, Zhou J, Zhang J, Yan Q, Huang L. Effect of Ferredoxin Receptor FusA on the Virulence Mechanism of Pseudomonas plecoglossicida. Front Cell Infect Microbiol 2022; 12:808800. [PMID: 35392610 PMCID: PMC8981516 DOI: 10.3389/fcimb.2022.808800] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Accepted: 02/17/2022] [Indexed: 12/21/2022] Open
Abstract
Pseudomonas plecoglossicida is an aerobic Gram-negative bacterium, which is the pathogen of “Visceral white spot disease” in large yellow croaker. P. plecoglossicida is a temperature-dependent bacterial pathogen in fish, which not only reduces the yield of large yellow croaker but also causes continuous transmission of the disease, seriously endangering the healthy development of fisheries. In this study, a mutant strain of fusA was constructed using homologous recombination technology. The results showed that knockout of P. plecoglossicida fusA significantly affected the ability of growth, adhesion, and biofilm formation. Temperature, pH, H2O2, heavy metals, and the iron-chelating agent were used to treat the wild type of P. plecoglossicida; the results showed that the expression of fusA was significantly reduced at 4°C, 12°C, and 37°C. The expression of fusA was significantly increased at pH 4 and 5. Cu2+ has a significant inducing effect on the expression of fusA, but Pb2+ has no obvious effect; the expression of fusA was significantly upregulated under different concentrations of H2O2. The expression of the fusA gene was significantly upregulated in the 0.5~4-μmol/l iron-chelating agent. The expression level of the fusA gene was significantly upregulated after the logarithmic phase. It was suggested that fusA included in the TBDR family not only was involved in the transport of ferredoxin but also played important roles in the pathogenicity and environment adaptation of P. plecoglossicida.
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Affiliation(s)
- Rongchao He
- Fisheries College, Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Jimei University, Xiamen, China
| | - Jiajia Wang
- Fisheries College, Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Jimei University, Xiamen, China
| | - Miaozhen Lin
- Fisheries College, Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Jimei University, Xiamen, China
| | - Jing Tian
- Fisheries College, Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Jimei University, Xiamen, China
| | - Bi Wu
- Fisheries College, Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Jimei University, Xiamen, China
| | - Xiaohan Tan
- College of Food and Biological Engineering, Jimei University, Xiamen, China
| | - Jianchuan Zhou
- Fisheries College, Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Jimei University, Xiamen, China
| | - Jiachen Zhang
- College of Food and Biological Engineering, Jimei University, Xiamen, China
| | - Qingpi Yan
- Fisheries College, Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Jimei University, Xiamen, China
- *Correspondence: Qingpi Yan, ; Lixing Huang,
| | - Lixing Huang
- Fisheries College, Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Jimei University, Xiamen, China
- *Correspondence: Qingpi Yan, ; Lixing Huang,
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11
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Qi W, Gao Q, Tian J, Wu B, Lin M, Qi S, Yan Q, Huang L. Immune responses and inorganic ion transport regulations of Epinephelus coioides in response to L321_RS13075 gene of Pseudomonas plecoglossicida. FISH & SHELLFISH IMMUNOLOGY 2022; 120:599-609. [PMID: 34968707 DOI: 10.1016/j.fsi.2021.12.036] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 12/20/2021] [Accepted: 12/21/2021] [Indexed: 06/14/2023]
Abstract
Pseudomonas plecoglossicida is a well-known pathogen of viscera granulomas disease in fish, which has led to severe economic losses. In our previous study, L321_RS13075 was predicted to be a key virulence gene of P. plecoglossicida during the host-pathogen interaction with Epinephelus coioides. To investigate the role of L321_RS13075 in the regulation of virulence in P. plecoglossicida, a L321_RS13075 knock-down strain was constructed. And a significant reduction in the ability of colonization, intracellular survival, motility, biofilm formation, and adhesion was detected in the L321_RS13075 knock-down strain. Compared with the wild-type strain, the silence of L321_RS13075 in P. plecoglossicida resulted in a significant change in the transcriptome of infected Epinephelus coioides (E. coioides). Results of COG and GO analysis on E. coioides showed that genes related to immune responses and inorganic ion transport were significantly affected by L321_RS13075 of P. plecoglossicida. Meanwhile, the interactions of the genes related to immune responses and inorganic ion transport were predicted, and the important hub genes were identified. Taken together, the results indicated that L321_RS13075 was a virulent gene of P. plecoglossicida, which significantly affected the immune responses and inorganic ion transport in E. coioides.
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Affiliation(s)
- Weilu Qi
- Fisheries College, Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Jimei University, Xiamen, Fujian, PR China
| | - Qiancheng Gao
- Fisheries College, Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Jimei University, Xiamen, Fujian, PR China
| | - Jing Tian
- Fisheries College, Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Jimei University, Xiamen, Fujian, PR China
| | - Bi Wu
- Fisheries College, Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Jimei University, Xiamen, Fujian, PR China
| | - Miaozhen Lin
- Fisheries College, Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Jimei University, Xiamen, Fujian, PR China
| | - Shanni Qi
- Fisheries College, Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Jimei University, Xiamen, Fujian, PR China
| | - Qingpi Yan
- Fisheries College, Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Jimei University, Xiamen, Fujian, PR China.
| | - Lixing Huang
- Fisheries College, Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Jimei University, Xiamen, Fujian, PR China; Fujian Province Key Laboratory of Special Aquatic Formula Feed, Fujian Tianma Science and Technology Group Co., Ltd., PR China.
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12
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Huang L, Qiao Y, Xu W, Gong L, He R, Qi W, Gao Q, Cai H, Grossart HP, Yan Q. Full-Length Transcriptome: A Reliable Alternative for Single-Cell RNA-Seq Analysis in the Spleen of Teleost Without Reference Genome. Front Immunol 2021; 12:737332. [PMID: 34646272 PMCID: PMC8502891 DOI: 10.3389/fimmu.2021.737332] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Accepted: 09/10/2021] [Indexed: 12/12/2022] Open
Abstract
Fish is considered as a supreme model for clarifying the evolution and regulatory mechanism of vertebrate immunity. However, the knowledge of distinct immune cell populations in fish is still limited, and further development of techniques advancing the identification of fish immune cell populations and their functions are required. Single cell RNA-seq (scRNA-seq) has provided a new approach for effective in-depth identification and characterization of cell subpopulations. Current approaches for scRNA-seq data analysis usually rely on comparison with a reference genome and hence are not suited for samples without any reference genome, which is currently very common in fish research. Here, we present an alternative, i.e. scRNA-seq data analysis with a full-length transcriptome as a reference, and evaluate this approach on samples from Epinephelus coioides-a teleost without any published genome. We show that it reconstructs well most of the present transcripts in the scRNA-seq data achieving a sensitivity equivalent to approaches relying on genome alignments of related species. Based on cell heterogeneity and known markers, we characterized four cell types: T cells, B cells, monocytes/macrophages (Mo/MΦ) and NCC (non-specific cytotoxic cells). Further analysis indicated the presence of two subsets of Mo/MΦ including M1 and M2 type, as well as four subsets in B cells, i.e. mature B cells, immature B cells, pre B cells and early-pre B cells. Our research will provide new clues for understanding biological characteristics, development and function of immune cell populations of teleost. Furthermore, our approach provides a reliable alternative for scRNA-seq data analysis in teleost for which no reference genome is currently available.
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Affiliation(s)
- Lixing Huang
- Fisheries College, Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Jimei University, Xiamen, China
| | - Ying Qiao
- Fourth Institute of Oceanography, Ministry of Natural Resources, Beihai, China
| | - Wei Xu
- Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, China
| | - Linfeng Gong
- Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, China
| | - Rongchao He
- Fisheries College, Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Jimei University, Xiamen, China
| | - Weilu Qi
- Fisheries College, Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Jimei University, Xiamen, China
| | - Qiancheng Gao
- Fisheries College, Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Jimei University, Xiamen, China
| | - Hongyan Cai
- Fisheries College, Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Jimei University, Xiamen, China
| | - Hans-Peter Grossart
- Department of Experimental Limnology, Leibniz Institute of Freshwater Ecology and Inland Fisheries, Stechlin, Germany.,Institute of Biochemistry and Biology, Postdam University, Potsdam, Germany
| | - Qingpi Yan
- Fisheries College, Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Jimei University, Xiamen, China
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