1
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Wang C, Defoirdt T, Rajkovic A. The impact of indole and mucin on sporulation, biofilm formation, and enterotoxin production in foodborne Clostridium perfringens. J Appl Microbiol 2024; 135:lxae083. [PMID: 38544331 DOI: 10.1093/jambio/lxae083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Revised: 03/13/2024] [Accepted: 03/26/2024] [Indexed: 04/12/2024]
Abstract
AIMS Indole and mucin are compounds found in the host environment as they are produced by the host or by the host-associated microbiota. This study investigated whether indole and mucin impact Clostridium perfringens growth and sporulation, as well as enterotoxin production and biofilm formation. METHODS AND RESULTS There was no impact on growth of Cl. perfringens for up to 400 µM indole and 240 mg/l mucin, and neither indole nor mucin affected sporulation. Reverse-transcriptase qPCR showed that mucin strongly upregulated the expression of Cl. perfringens enterotoxin (up to 121-fold increase), whereas indole had a much more modest effect (2-fold). This was also reflected in increased Cl. perfringens enterotoxin levels in mucin-treated Cl. perfringens (as assessed by a reversed passive latex agglutination assay). Finally, mucin and indole significantly increased biofilm formation of Cl. perfringens, although the effect size was relatively small (less than 1.5 fold). CONCLUSION These results indicate that Cl. perfringens can sense its presence in a host environment by responding to mucin, and thereby markedly increased enterotoxin production.
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Affiliation(s)
- Chao Wang
- Research Unit Food Microbiology and Food Preservation, Department of Food Technology, Safety and Health, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000 Ghent, Belgium
| | - Tom Defoirdt
- Center for Microbial Ecology and Technology, Department of Biotechnology, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000 Ghent, Belgium
| | - Andreja Rajkovic
- Research Unit Food Microbiology and Food Preservation, Department of Food Technology, Safety and Health, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000 Ghent, Belgium
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2
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Yin Z, Nie H, Jiang K, Yan X. Molecular Mechanisms Underlying Vibrio Tolerance in Ruditapes philippinarum Revealed by Comparative Transcriptome Profiling. Front Immunol 2022; 13:879337. [PMID: 35615362 PMCID: PMC9125321 DOI: 10.3389/fimmu.2022.879337] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2022] [Accepted: 04/05/2022] [Indexed: 12/13/2022] Open
Abstract
The clam Ruditapes philippinarum is an important species in the marine aquaculture industry in China. However, in recent years, the aquaculture of R. philippinarum has been negatively impacted by various bacterial pathogens. In this study, the transcriptome libraries of R. philippinarum showing different levels of resistance to challenge with Vibrio anguillarum were constructed and RNA-seq was performed using the Illumina sequencing platform. Host immune factors were identified that responded to V. anguillarum infection, including C-type lectin domain, glutathione S-transferase 9, lysozyme, methyltransferase FkbM domain, heat shock 70 kDa protein, Ras-like GTP-binding protein RHO, C1q, F-box and BTB/POZ domain protein zf-C2H2. Ten genes were selected and verified by RT-qPCR, and nine of the gene expression results were consistent with those of RNA-seq. The lectin gene in the phagosome pathway was expressed at a significantly higher level after V. anguillarum infection, which might indicate the role of lectin in the immune response to V. anguillarum. Comparing the results from R. philippinarum resistant and nonresistant to V. anguillarum increases our understanding of the resistant genes and key pathways related to Vibrio challenge in this species. The results obtained here provide a reference for future immunological research focusing on the response of R. philippinarum to V. anguillarum infection.
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Affiliation(s)
- Zhihui Yin
- Engineering and Technology Research Center of Shellfish Breeding in Liaoning Province, College of Fisheries and Life Science, Dalian Ocean University, Dalian, China
| | - Hongtao Nie
- Engineering and Technology Research Center of Shellfish Breeding in Liaoning Province, College of Fisheries and Life Science, Dalian Ocean University, Dalian, China
| | - Kunyin Jiang
- Engineering and Technology Research Center of Shellfish Breeding in Liaoning Province, College of Fisheries and Life Science, Dalian Ocean University, Dalian, China
| | - Xiwu Yan
- Engineering and Technology Research Center of Shellfish Breeding in Liaoning Province, College of Fisheries and Life Science, Dalian Ocean University, Dalian, China
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3
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Ou W, Yu G, Zhang Y, Mai K. Recent progress in the understanding of the gut microbiota of marine fishes. MARINE LIFE SCIENCE & TECHNOLOGY 2021; 3:434-448. [PMID: 37073265 PMCID: PMC10077274 DOI: 10.1007/s42995-021-00094-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2020] [Accepted: 01/12/2021] [Indexed: 05/03/2023]
Abstract
As the significance of the gut microbiota has become increasingly realized, a large number of related studies have emerged. With respect to the gut microbial composition of fish, the predominant gut microbes and core gut microbiota have been reported by many researchers. Our understanding of fish gut microbiota, especially its functional roles, has fallen far behind that of terrestrial vertebrates, although previous studies using gnotobiotic zebrafish models have revealed that the gut microbiota performs a significant role in gut development, nutrient metabolism and immune responses. Given that environmental factors of marine habitats are very different from those of freshwater habitats, a distinct difference may exist in the gut microbiota between freshwater and marine fish. Therefore, this review aims to address the advances in marine fish gut microbiota in terms of methodologies, the gut microbial composition, and gnotobiotic models of marine fish, the important factors (host genotype and three environmental factors: temperature, salinity and diet) that drive marine fish gut microbiota, and significant roles of the gut microbiota in marine fish.
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Affiliation(s)
- Weihao Ou
- The Key Laboratory of Aquaculture Nutrition and Feed (Ministry of Agriculture) and the Key Laboratory of Mariculture (Ministry of Education), Ocean University of China, Qingdao, 266003 China
| | - Guijuan Yu
- The Key Laboratory of Aquaculture Nutrition and Feed (Ministry of Agriculture) and the Key Laboratory of Mariculture (Ministry of Education), Ocean University of China, Qingdao, 266003 China
| | - Yanjiao Zhang
- The Key Laboratory of Aquaculture Nutrition and Feed (Ministry of Agriculture) and the Key Laboratory of Mariculture (Ministry of Education), Ocean University of China, Qingdao, 266003 China
- Laboratory for Marine Fisheries Science and Food Production Processes, Pilot National Laboratory for Marine Science and Technology, Qingdao, 266237 China
| | - Kangsen Mai
- The Key Laboratory of Aquaculture Nutrition and Feed (Ministry of Agriculture) and the Key Laboratory of Mariculture (Ministry of Education), Ocean University of China, Qingdao, 266003 China
- Laboratory for Marine Fisheries Science and Food Production Processes, Pilot National Laboratory for Marine Science and Technology, Qingdao, 266237 China
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4
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Can only one physiological trait determinate the adverse effect of green fluorescent protein (GFP) incorporation on Vibrio virulence? Appl Microbiol Biotechnol 2021; 105:7899-7912. [PMID: 34559285 DOI: 10.1007/s00253-021-11556-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 08/23/2021] [Accepted: 08/25/2021] [Indexed: 10/20/2022]
Abstract
Green fluorescent protein (GFP) has been used extensively for in situ animal studies that follow up bacterial infection under epifluorescence microscopy. It is assumed that GFP is acting as a "neutral" protein with no influence on the bacterial physiology. To verify this hypothesis, the virulence of Vibrio splendidus ME9, Vibrio anguillarum NB10, and their respective GFP-tagged strains ME9-GFP and NB10-GFP (transconjugants) was compared in vitro and tested in vivo towards blue mussel (Mytilus edulis) larvae. Results showed that the incorporation of GFP negatively impacted the growth and swimming motility of NB10 in vitro. Correspondingly, the mRNA levels of genes involved in bacterial swimming motility (flaA, flaE, and cheR) were significantly down-regulated in NB10-GFP. As for the strain ME9 on the other hand, GFP incorporation only had a negative effect on swimming motility. However, both the strains NB10-GFP and ME9-GFP showed almost the same virulence as their respective parental strain towards mussel larvae in vivo. Overall, the data presented here demonstrated that incorporation of GFP may cause modifications in cell physiology and highlight the importance of preliminary physiological tests to minimize the negative influence of GFP tagging when it is used to monitor the target localization. The study also supports the idea that the virulence of Vibrio species is determined by complex regulatory networks. Notwithstanding the change of a single physiological trait, especially growth or swimming motility, the GFP-tagged Vibrio strain can thus still be considered usable in studies mainly focusing on the virulence of the strain. KEY POINTS: • The effect of GFP incorporation on physiological trait of Vibrio strains. • The virulence in vibrios could be multifactorial. • The stable virulence of Vibrio strains after GFP incorporation.
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5
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Chen C, Xu C, Qian D, Yu Q, Huang M, Zhou L, Qin JG, Chen L, Li E. Growth and health status of Pacific white shrimp, Litopenaeus vannamei, exposed to chronic water born cobalt. FISH & SHELLFISH IMMUNOLOGY 2020; 100:137-145. [PMID: 32151686 DOI: 10.1016/j.fsi.2020.03.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Revised: 03/03/2020] [Accepted: 03/05/2020] [Indexed: 06/10/2023]
Abstract
Cobalt (Co) is an important component of vitamin B12, but is toxic to aquatic animals at a high level. In this study, the Pacific white shrimp, Litopenaeus vannamei were exposed to three Co concentrations (0, 100, and 1000 μg/L) for 4 weeks. The survival and condition factor in shrimp exposed to the Co treatments were not different from the control, but the shrimp exposed to 100 μg Co/L gained more weight than in other two groups, and the shrimp exposed to 1000 μg Co/L gained less weight than in other groups. The SOD and GSH-PX activities were higher in shrimp exposed to 100 μg Co/L, but lower in the shrimp exposed to 100 μg Co/L compared with the control, respectively. The MDA contents in the hepatopancreas decreased in the 100 μg Co/L, but increased in the 1000 μg Co/L. The serum lysozyme decreased with ambient cobalt, was lower in the shrimp exposed to 1000 μg Co/L than in other two groups. The expression of C-type lectin 3 was down-regulated by Co concentrations. The Toll and immune deficiency in shrimp exposed to 100 μg Co/L was higher than in other two groups. The mucin-1 was lower in the 1000 μg Co/L group than in other two groups, but mucin-2 and mucin-5AC were higher in the 1000 μg Co/L group than in the control. With increasing Co concentration, Shannon and Simpson indexes of the intestinal microbial communities were decreased. The abundance of pathogenic bacteria (Ruegeria and Vibrio) increased in both Co groups. This study indicates that chronic exposure to waterborne cobalt could affect growth, cause oxidative stress, stimulate the immune response, damage intestinal histology, and reshape intestinal microbiota community L. vannamei.
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Affiliation(s)
- Chengzhuang Chen
- Key Laboratory of Tropical Hydrobiology and Biotechnology of Hainan Province, Hainan University, Haikou, Hainan, 570228, China; Department of Aquaculture, College of Marine Sciences, Hainan University, Haikou, Hainan, 570228, China
| | - Chang Xu
- Key Laboratory of Tropical Hydrobiology and Biotechnology of Hainan Province, Hainan University, Haikou, Hainan, 570228, China; Department of Aquaculture, College of Marine Sciences, Hainan University, Haikou, Hainan, 570228, China.
| | - Dunwei Qian
- Key Laboratory of Tropical Hydrobiology and Biotechnology of Hainan Province, Hainan University, Haikou, Hainan, 570228, China; Department of Aquaculture, College of Marine Sciences, Hainan University, Haikou, Hainan, 570228, China
| | - Qiuran Yu
- Key Laboratory of Tropical Hydrobiology and Biotechnology of Hainan Province, Hainan University, Haikou, Hainan, 570228, China; Department of Aquaculture, College of Marine Sciences, Hainan University, Haikou, Hainan, 570228, China
| | - Maoxian Huang
- Key Laboratory of Tropical Hydrobiology and Biotechnology of Hainan Province, Hainan University, Haikou, Hainan, 570228, China; Department of Aquaculture, College of Marine Sciences, Hainan University, Haikou, Hainan, 570228, China
| | - Li Zhou
- Key Laboratory of Tropical Hydrobiology and Biotechnology of Hainan Province, Hainan University, Haikou, Hainan, 570228, China; Department of Aquaculture, College of Marine Sciences, Hainan University, Haikou, Hainan, 570228, China
| | - Jian G Qin
- School of Biological Sciences, Flinders University, Adelaide, SA, 5001, Australia
| | - Liqiao Chen
- School of Life Sciences, East China Normal University, Shanghai, 200241, China
| | - Erchao Li
- Key Laboratory of Tropical Hydrobiology and Biotechnology of Hainan Province, Hainan University, Haikou, Hainan, 570228, China; Department of Aquaculture, College of Marine Sciences, Hainan University, Haikou, Hainan, 570228, China.
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6
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Guanhua Y, Wang C, Wang X, Ma R, Zheng H, Liu Q, Zhang Y, Ma Y, Wang Q. Complete genome sequence of the marine fish pathogen Vibrio anguillarum and genome-wide transposon mutagenesis analysis of genes essential for in vivo infection. Microbiol Res 2018; 216:97-107. [DOI: 10.1016/j.micres.2018.08.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 08/21/2018] [Accepted: 08/23/2018] [Indexed: 12/14/2022]
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7
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Xu Q, Shan Y, Wang N, Liu Y, Zhang M, Ma M. Sialic acid involves in the interaction between ovomucin and hemagglutinin and influences the antiviral activity of ovomucin. Int J Biol Macromol 2018; 119:533-539. [PMID: 30071221 PMCID: PMC7124660 DOI: 10.1016/j.ijbiomac.2018.07.186] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2018] [Revised: 07/23/2018] [Accepted: 07/29/2018] [Indexed: 11/27/2022]
Abstract
Ovomucin (OVM) plays an important role in inhibiting infection of various pathogens. However, this bioactivity mechanism is not much known. Here, the role of sialic acid in OVM anti-virus activity has been studied by ELISA with lectin or ligand. Structural changes of OVM after removing sialic acid were analyzed by circular dichroism and fluorescence spectroscopy. OVM could be binding to the hemagglutinin (HA) of avian influenza viruses H5N1 and H1N1, this binding was specific and required the involvement of sialic acid. When sialic acid was removed, the binding was significantly reduced 71.5% and 64.35%, respectively. Therefore, sialic acid was proved as a recognition site which avian influenza virus bound to. Meanwhile, the endogenous fluorescence and surface hydrophobicity of OVM removing sialic acid were increased and the secondary structure tended to shift to random coil. This indicated that OVM molecules were in an unfolded state and spatial conformation disorder raising weakly. Remarkably, free sialic acid strongly promoted OVM binding to HA and thereby enhanced the interaction. It may contribute to the inhibition of host cell infection, agglutinate viruses. This study can be extended to the deepening of passive immunization field.
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Affiliation(s)
- Qi Xu
- College of Food Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, People's Republic of China
| | - Yuanyuan Shan
- College of Food Science and Engineering, Northwest A&F University, Yangling 712100, People's Republic of China
| | - Ning Wang
- College of Food Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, People's Republic of China
| | - Yaping Liu
- College of Food Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, People's Republic of China
| | - Maojie Zhang
- College of Food Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, People's Republic of China
| | - Meihu Ma
- College of Food Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, People's Republic of China.
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8
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Duan Y, Liu Q, Wang Y, Zhang J, Xiong D. Impairment of the intestine barrier function in Litopenaeus vannamei exposed to ammonia and nitrite stress. FISH & SHELLFISH IMMUNOLOGY 2018; 78:279-288. [PMID: 29709590 DOI: 10.1016/j.fsi.2018.04.050] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Revised: 04/21/2018] [Accepted: 04/23/2018] [Indexed: 06/08/2023]
Abstract
Intestine barrier serves as the front-line of shrimp defense, which rely on its structural integrity, microbial composition, and mucus immune compounds. Mucins are the major organic components of the intestine mucus layer that contribute to the immunity of intestine mucus. In this study, we examined the histological structure, microbial composition, and mucin genes expression in the intestines of Litopenaeus vanmei under three different conditions: control, ammonia stress, and nitrite stress for 72 h. H&E stain showed that ammonia and nitrite stress exposure both damaged the intestine mucosal tissue. High-throughput 16S rDNA sequencing revealed that two stresses exposure decreased the bacterial diversity, and altered the composition of intestine microbial. Specifically, the dominant bacterial phyla Bacteroidetes abundance was increased, while Proteobacteria and Planctomycetes were decreased; at the genus level, Formosa abundance was increased and Photobacterium was decreased, opportunistic pathogens including Nautella and Pseudoalteromonas was also increased. Intestine mucus immune genes including mucin-2 and mucin-19 were up-regulated, while mucin-1, mucin-5AC, and mucin-5B were down-regulated in two stress exposure groups. These results revealed that ammonia and nitrite stress harmed the intestine barrier function of L. vannamei by damaging the mucosal tissue, disrupting the composition of intestine microbial, and suppressing the immune function.
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Affiliation(s)
- Yafei Duan
- Key Laboratory of South China Sea Fishery Resources Exploitation & Utilization, Ministry of Agriculture, Key Laboratory of Fishery Ecology and Environment, Guangdong Province, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, 510300, PR China
| | - Qingsong Liu
- Key Laboratory of South China Sea Fishery Resources Exploitation & Utilization, Ministry of Agriculture, Key Laboratory of Fishery Ecology and Environment, Guangdong Province, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, 510300, PR China
| | - Yun Wang
- Key Laboratory of South China Sea Fishery Resources Exploitation & Utilization, Ministry of Agriculture, Key Laboratory of Fishery Ecology and Environment, Guangdong Province, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, 510300, PR China
| | - Jiasong Zhang
- Key Laboratory of South China Sea Fishery Resources Exploitation & Utilization, Ministry of Agriculture, Key Laboratory of Fishery Ecology and Environment, Guangdong Province, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, 510300, PR China.
| | - Dalin Xiong
- Key Laboratory of South China Sea Fishery Resources Exploitation & Utilization, Ministry of Agriculture, Key Laboratory of Fishery Ecology and Environment, Guangdong Province, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, 510300, PR China
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9
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Gao C, Fu Q, Su B, Zhou S, Liu F, Song L, Zhang M, Ren Y, Dong X, Tan F, Li C. Transcriptomic profiling revealed the signatures of intestinal barrier alteration and pathogen entry in turbot (Scophthalmus maximus) following Vibrio anguillarum challenge. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2016; 65:159-168. [PMID: 27431928 DOI: 10.1016/j.dci.2016.07.007] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Revised: 07/14/2016] [Accepted: 07/14/2016] [Indexed: 06/06/2023]
Abstract
The mucosal immune system serves as the frontline barriers of host defense against pathogen infection, especially for the fishes, which are living in the pathogen rich aquatic environment. The intestine constitutes the largest surface body area in constantly contact with the external pathogens, and plays a vital role in the immune defense against inflammation and pathogen infection. Previous studies have revealed that fish intestine might serves as the portal of entry for Vibrio anguillarum. To characterize the immune actors and their associated immune activities in turbot intestine barrier during bacterial infection, here we examined the gene expression profiles of turbot intestine at three time points following experimental infection with V. anguillarum utilizing RNA-seq technology. A total of 122 million reads were assembled into 183,101 contigs with an average length of 1151 bp and the N50 size of 2302 bp. Analysis of differential gene expression between control and infected samples at 1 h, 4 h, and 12 h revealed 2079 significantly expressed genes. Enrichment and pathway analysis of the differentially expressed genes showed the centrality of the pathogen attachment and recognition, antioxidant/apoptosis, mucus barrier modification and immune activation/inflammation in the pathogen entry and host immune responses. The present study reported the novel gene expression patterns in turbot mucosal immunity, which were overlooked in previous studies. Our results can help to understand the mechanisms of turbot host defense, and may also provide foundation to identify the biomarkers for future selection of disease-resistant broodstock and evaluation of disease prevention and treatment options.
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Affiliation(s)
- Chengbin Gao
- Marine Science and Engineering College, Qingdao Agricultural University, Qingdao, 266109, China
| | - Qiang Fu
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai, 200062, China
| | - Baofeng Su
- Ministry of Agriculture Key Laboratory of Freshwater Aquatic Biotechnology and Breeding, Heilongjiang Fisheries Research Institute, Chinese Academy of Fishery Sciences, Harbin, 150070, China; National and Local Joint Engineering Laboratory for Freshwater Fish Breeding, Heilongjiang Fisheries Research Institute, Chinese Academy of Fishery Sciences, Harbin, 150070, China
| | - Shun Zhou
- Marine Science and Engineering College, Qingdao Agricultural University, Qingdao, 266109, China
| | - Fengqiao Liu
- Marine Science and Engineering College, Qingdao Agricultural University, Qingdao, 266109, China
| | - Lin Song
- Marine Science and Engineering College, Qingdao Agricultural University, Qingdao, 266109, China
| | - Min Zhang
- Marine Science and Engineering College, Qingdao Agricultural University, Qingdao, 266109, China
| | - Yichao Ren
- Marine Science and Engineering College, Qingdao Agricultural University, Qingdao, 266109, China
| | - Xiaoyu Dong
- Marine Science and Engineering College, Qingdao Agricultural University, Qingdao, 266109, China
| | - Fenghua Tan
- School of International Education and Exchange, Qingdao Agricultural University, Qingdao, 266109, China
| | - Chao Li
- Marine Science and Engineering College, Qingdao Agricultural University, Qingdao, 266109, China.
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Biofilm Formation and Detachment in Gram-Negative Pathogens Is Modulated by Select Bile Acids. PLoS One 2016; 11:e0149603. [PMID: 26992172 PMCID: PMC4798295 DOI: 10.1371/journal.pone.0149603] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Accepted: 02/03/2016] [Indexed: 11/19/2022] Open
Abstract
Biofilms are a ubiquitous feature of microbial community structure in both natural and host environments; they enhance transmission and infectivity of pathogens and provide protection from human defense mechanisms and antibiotics. However, few natural products are known that impact biofilm formation or persistence for either environmental or pathogenic bacteria. Using the combination of a novel natural products library from the fish microbiome and an image-based screen for biofilm inhibition, we describe the identification of taurine-conjugated bile acids as inhibitors of biofilm formation against both Vibrio cholerae and Pseudomonas aeruginosa. Taurocholic acid (1) was isolated from the fermentation broth of the fish microbiome-derived strain of Rhodococcus erythropolis and identified using standard NMR and MS methods. Screening of the twelve predominant human steroidal bile acid components revealed that a subset of these compounds can inhibit biofilm formation, induce detachment of preformed biofilms under static conditions, and that these compounds display distinct structure-activity relationships against V. cholerae and P. aeruginosa. Our findings highlight the significance of distinct bile acid components in the regulation of biofilm formation and dispersion in two different clinically relevant bacterial pathogens, and suggest that the bile acids, which are endogenous mammalian metabolites used to solubilize dietary fats, may also play a role in maintaining host health against bacterial infection.
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11
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Ruwandeepika HAD, Karunasagar I, Bossier P, Defoirdt T. Expression and Quorum Sensing Regulation of Type III Secretion System Genes of Vibrio harveyi during Infection of Gnotobiotic Brine Shrimp. PLoS One 2015; 10:e0143935. [PMID: 26636765 PMCID: PMC4670211 DOI: 10.1371/journal.pone.0143935] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Accepted: 11/11/2015] [Indexed: 12/24/2022] Open
Abstract
Type III secretion systems enable pathogens to inject their virulence factors directly into the cytoplasm of the host cells. The type III secretion system of Vibrio harveyi, a major pathogen of aquatic organisms and a model species in quorum sensing studies, is repressed by the quorum sensing master regulator LuxR. In this study, we found that during infection of gnotobiotic brine shrimp larvae, the expression levels of three type III secretion operons in V. harveyi increased within the first 12h after challenge and decreased again thereafter. The in vivo expression levels were highest in a mutant with a quorum sensing system that is locked in low cell density configuration (minimal LuxR levels) and lowest in a mutant with a quorum sensing system that is locked in the high cell density configuration (maximal LuxR levels), which is consistent with repression of type III secretion by LuxR. Remarkably, in vivo expression levels of the type III secretion system genes were much (> 1000 fold) higher than the in vitro expression levels, indicating that (currently unknown) host factors significantly induce the type III secretion system. Given the fact that type III secretion is energy-consuming, repression by the quorum sensing master regulators might be a mechanism to save energy under conditions where it does not provide an advantage to the cells.
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Affiliation(s)
- H. A. Darshanee Ruwandeepika
- Department of Livestock Production, Faculty of Agricultural Sciences, Sabaragamuwa University of Sri Lanka, Belihuloya, Sri Lanka
- Centre for Science Education and Research, UNESCO MIRCEN for Medical and Marine Biotechnology, Nitte University, Mangalore, India
| | - Indrani Karunasagar
- Centre for Science Education and Research, UNESCO MIRCEN for Medical and Marine Biotechnology, Nitte University, Mangalore, India
| | - Peter Bossier
- Laboratory of Aquaculture & Artemia Reference Center, Ghent University, Ghent, Belgium
| | - Tom Defoirdt
- Laboratory of Aquaculture & Artemia Reference Center, Ghent University, Ghent, Belgium
- * E-mail:
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12
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Li X, Defoirdt T, Bossier P. Relation between virulence of Vibrio anguillarum strains and response to the host factors mucin, bile salts and cholesterol. J Appl Microbiol 2015; 119:25-32. [PMID: 25807847 DOI: 10.1111/jam.12813] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Revised: 03/18/2015] [Accepted: 03/20/2015] [Indexed: 11/28/2022]
Abstract
AIMS In this study, we investigated the responsiveness of 15 Vibrio anguillarum strains to three host factors (mucin, bile salts and cholesterol). METHODS AND RESULTS Three virulence-related phenotypes were investigated in this respect, i.e. motility, biofilm formation and exopolysaccharide production. Almost all V. anguillarum strains showed a significantly increased motility in the presence of either of the three host factors. Only five of the strains showed increased biofilm formation in the presence of host factors and only three strains showed increased exopolysaccharide production in the presence of the host factors. CONCLUSIONS There were no significant correlations between the three putatively virulence-linked phenotypes (in the absence of host factors) and virulence to sea bass larvae. There was no correlation between responsiveness to the host factors (percentage increase in motility, biofilm formation or exopolysaccharide production in the presence of the three host factors) and virulence to sea bass larvae. However, the responses of these virulence-related phenotypes upon the addition of either of the three host factors were significantly correlated with each other. This result suggests that the mechanisms by which V. anguillarum responds to these three host factors is linked. SIGNIFICANCE AND IMPACT OF THE STUDY Although the mechanism by which V. anguillarum responds to the host factors mucin, bile salts and cholesterol seems to be linked, there is no correlation between host factor responsiveness and virulence towards sea bass larvae. This emphasizes that one should be careful when extrapolating results obtained for one particular strain to reach general conclusions on a species of pathogenic bacteria.
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Affiliation(s)
- X Li
- Laboratory of Aquaculture & Artemia Reference Center, Ghent University, Ghent, Belgium
| | - T Defoirdt
- Laboratory of Aquaculture & Artemia Reference Center, Ghent University, Ghent, Belgium
| | - P Bossier
- Laboratory of Aquaculture & Artemia Reference Center, Ghent University, Ghent, Belgium
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