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Thunes NC, Evenhuis JP, Lipscomb RS, Pérez-Pascual D, Stevick RJ, Birkett C, Ghigo JM, McBride MJ. Gliding motility proteins GldJ and SprB contribute to Flavobacterium columnare virulence. J Bacteriol 2024; 206:e0006824. [PMID: 38517170 PMCID: PMC11025331 DOI: 10.1128/jb.00068-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Accepted: 03/01/2024] [Indexed: 03/23/2024] Open
Abstract
Flavobacterium columnare causes columnaris disease in fish. Columnaris disease is incompletely understood, and adequate control measures are lacking. The type IX secretion system (T9SS) is required for F. columnare gliding motility and virulence. The T9SS and gliding motility machineries share some, but not all, components. GldN (required for gliding and for secretion) and PorV (involved in secretion but not required for gliding) are both needed for virulence, implicating T9SS-mediated secretion in virulence. The role of motility in virulence is uncertain. We constructed and analyzed sprB, sprF, and gldJ mutants that were defective for motility but that maintained T9SS function to understand the role of motility in virulence. Wild-type cells moved rapidly and formed spreading colonies. In contrast, sprB and sprF deletion mutants were partially defective in gliding and formed nonspreading colonies. Both mutants exhibited reduced virulence in rainbow trout fry. A gldJ deletion mutant was nonmotile, secretion deficient, and avirulent in rainbow trout fry. To separate the roles of GldJ in secretion and in motility, we generated gldJ truncation mutants that produce nearly full-length GldJ. Mutant gldJ563, which produces GldJ truncated at amino acid 563, was defective for gliding but was competent for secretion as measured by extracellular proteolytic activity. This mutant displayed reduced virulence in rainbow trout fry, suggesting that motility contributes to virulence. Fish that survived exposure to the sprB deletion mutant or the gldJ563 mutant exhibited partial resistance to later challenge with wild-type cells. The results aid our understanding of columnaris disease and may suggest control strategies.IMPORTANCEFlavobacterium columnare causes columnaris disease in many species of freshwater fish in the wild and in aquaculture systems. Fish mortalities resulting from columnaris disease are a major problem for aquaculture. F. columnare virulence is incompletely understood, and control measures are inadequate. Gliding motility and protein secretion have been suggested to contribute to columnaris disease, but evidence directly linking motility to disease was lacking. We isolated and analyzed mutants that were competent for secretion but defective for motility. Some of these mutants exhibited decreased virulence. Fish that had been exposed to these mutants were partially protected from later exposure to the wild type. The results contribute to our understanding of columnaris disease and may aid development of control strategies.
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Affiliation(s)
- Nicole C. Thunes
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, USA
| | - Jason P. Evenhuis
- National Center for Cool and Cold Water Aquaculture, Agricultural Research Service, USDA, Kearneysville, West Virginia, USA
| | - Ryan S. Lipscomb
- National Center for Cool and Cold Water Aquaculture, Agricultural Research Service, USDA, Kearneysville, West Virginia, USA
| | - David Pérez-Pascual
- Institut Pasteur, Université Paris-Cité, CNRS UMR 6047, Genetics of Biofilms Laboratory, Paris, France
| | - Rebecca J. Stevick
- Institut Pasteur, Université Paris-Cité, CNRS UMR 6047, Genetics of Biofilms Laboratory, Paris, France
| | - Clayton Birkett
- National Center for Cool and Cold Water Aquaculture, Agricultural Research Service, USDA, Kearneysville, West Virginia, USA
| | - Jean-Marc Ghigo
- Institut Pasteur, Université Paris-Cité, CNRS UMR 6047, Genetics of Biofilms Laboratory, Paris, France
| | - Mark J. McBride
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, USA
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Mishra S, Garg P, Srivastava S, Srivastava P. Br - nanoconjugate enhances the antibacterial efficacy of nimboloide against Flavobacterium columnare infection in Labeo rohita: A nanoinformatics approach. Microb Pathog 2024; 189:106575. [PMID: 38423405 DOI: 10.1016/j.micpath.2024.106575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 02/13/2024] [Accepted: 02/13/2024] [Indexed: 03/02/2024]
Abstract
BACKGROUND The bacterial pathogen, Flavobacterium columnare causes columnaris disease in Labeo rohita globally. Major effects of this bacterial infection include skin rashes and gill necrosis. Nimbolide, the key ingredient of the leaf extract of Azadirachta indica possesses anti-bacterial properties effective against many microorganisms. Nano-informatics plays a promising role in drug development and its delivery against infections caused by multi-drug-resistant bacteria. Currently, studies in the disciplines of dentistry, food safety, bacteriology, mycology, virology, and parasitology are being conducted to learn more about the wide anti-virulence activity of nimbolide. METHODS The toxicity of nimbolide was predicted to determine its dosage for treating bacterial infection in Labeo rohita. Further, comparative 3-D structure prediction and docking studies are done for nimbolide conjugated nanoparticles with several key target receptors to determine better natural ligands against columnaris disease. The nanoparticle conjugates are being designed using in-silico approaches to study molecular docking interactions with the target receptor. RESULTS Bromine conjugated nimbolide shows the best molecular interaction with the target receptors of selected species ie L rohita. Nimbolide comes under the class III level of toxic compound so, attempts are made to reduce the dosage of the compound without compromising its efficiency. Further, bromine is also used as a common surfactant and can eliminate heavy metals from wastewater. CONCLUSION The dosage of bromine-conjugated nimbolide can be reduced to a non-toxic level and thus the efficiency of the Nimbolide can be increased. Moreover, it can be used to synthesize nanoparticle composites which have potent antibacterial activity towards both gram-positive and gram-negative bacteria. This material also forms a good coating on the surface and kills both airborne and waterborne bacteria.
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Affiliation(s)
- Sanjana Mishra
- Amity Institute of Biotechnology, Amity University Uttar Pradesh, Lucknow Campus, 226028, India
| | - Prekshi Garg
- Amity Institute of Biotechnology, Amity University Uttar Pradesh, Lucknow Campus, 226028, India
| | - Shilpi Srivastava
- Amity Institute of Biotechnology, Amity University Uttar Pradesh, Lucknow Campus, 226028, India
| | - Prachi Srivastava
- Amity Institute of Biotechnology, Amity University Uttar Pradesh, Lucknow Campus, 226028, India.
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Pulkkinen K, Taskinen J. Nutrient enrichment increases virulence in an opportunistic environmental pathogen, with greater effect at low bacterial doses. FEMS Microbiol Ecol 2024; 100:fiae013. [PMID: 38305097 PMCID: PMC10959552 DOI: 10.1093/femsec/fiae013] [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: 08/25/2023] [Revised: 01/29/2024] [Accepted: 01/31/2024] [Indexed: 02/03/2024] Open
Abstract
Eutrophication of aquatic ecosystems is associated with an increased risk of pathogen infection via increased pathogen growth and host exposure via increased pathogen doses. Here, we studied the effect of nutrients on the virulence of an opportunistic bacterial pathogen of fish, Flavobacterium columnare, in challenge experiments with rainbow trout fingerlings. We hypothesized that removing all nutrients by washing the bacteria would reduce virulence as compared to unwashed bacteria, but adding nutrients to the tank water would increase the virulence of the bacterium. Nutrient addition and increase in bacterial dose increased virulence for both unwashed and washed bacteria. For unwashed bacteria, the addition of nutrients reduced the survival probability of fish challenged with low bacterial doses more than for fish challenged with higher bacterial doses, suggesting activation of bacterial virulence factors. Washing and centrifugation reduced viable bacterial counts, and the addition of washed bacteria alone did not lead to fish mortality. However, a small addition of nutrient medium, 0.05% of the total water volume, added separately to the fish container, restored the virulence of the washed bacteria. Our results show that human-induced eutrophication could trigger epidemics of aquatic pathogens at the limits of their survival and affect their ecology and evolution by altering the dynamics between strains that differ in their growth characteristics.
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Affiliation(s)
- Katja Pulkkinen
- Department of Biological and Environmental Science, P.O. Box 35 (Survontie 9), University of Jyväskylä, Jyväskylä, Finland
| | - Jouni Taskinen
- Department of Biological and Environmental Science, P.O. Box 35 (Survontie 9), University of Jyväskylä, Jyväskylä, Finland
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4
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Olymon K, Yadav M, Teronpi V, Kumar A. Unravelling the genomic secrets of bacterial fish pathogens: a roadmap to aquaculture sustainability. Mol Biol Rep 2024; 51:364. [PMID: 38407655 DOI: 10.1007/s11033-024-09331-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Accepted: 02/07/2024] [Indexed: 02/27/2024]
Abstract
In the field of aquaculture, bacterial pathogens pose significant challenges to fish health and production. Advancements in genomic technologies have revolutionized our understanding of bacterial fish pathogens and their interactions with their host species. This review explores the application of genomic approaches in the identification, classification, and characterization of bacterial fish pathogens. Through an extensive analysis of the literature, we have compiled valuable data on 79 bacterial fish pathogens spanning 13 different phyla, encompassing their whole genome sequences. By leveraging high-throughput sequencing techniques, researchers have gained valuable insights into the genomic makeup of these pathogens, enabling a deeper understanding of their virulence factors and mechanisms of host interaction. Furthermore, genomic approaches have facilitated the discovery of potential vaccine and drug targets, opening up new avenues for the development of effective interventions against fish pathogens. Additionally, the utilization of genomics in fish disease resistance and control in aquaculture has shown promising results, enabling the identification of genetic markers associated with disease resistance traits. This review highlights the significant contributions of genomics to the field of fish pathogen research and underscores its potential for improving disease management strategies and enhancing the sustainability of aquaculture practices.
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Affiliation(s)
- Kaushika Olymon
- Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur, Assam, 784028, India
| | - Mohit Yadav
- Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur, Assam, 784028, India
| | - Valentina Teronpi
- Department, of Zoology, Pandit Deendayal Upadhyaya Adarsha Mahavidyalaya, Behali, Biswanath, Assam, 784184, India.
| | - Aditya Kumar
- Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur, Assam, 784028, India.
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Duman M, Satıcıoğlu IB, Janda JM. A Review of the Industrial Importance, Common Bacterial Diseases, and Zoonotic Risks of Freshwater Aquarium Fish. Vector Borne Zoonotic Dis 2024; 24:69-85. [PMID: 38133524 DOI: 10.1089/vbz.2023.0094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2023] Open
Abstract
Background: The ever-increasing popularity of home aquariums, most often involving freshwater varieties, has exploded in recent years partially due to the Coronavirus pandemic and related to stay-at-home public health precautions for social distancing. With this ever-increasing popularity of aquariums as a hobby, and whether this involves freshwater or marine fish species, a number of important economic, ecological, and public health issues arise for both fish and hobbyists alike. Materials and Methods: This review highlights the history and genesis of aquariums as both a hobby and an important economic factor (industrial, commercial) for many countries on a global basis. Types of aquarium fish are described, and culture conditions leading to homeostasis in aquatic environments are detailed. When these conditions are not met and aquatic systems are out of balance, the disease can result due to stressed fish. Results: Major bacterial diseases associated with freshwater aquarium fish are reviewed, as are potential human infections related to the care and maintenance of home aquaria. Conclusion: Besides, scientific information was also combined with the false facts of hobbyists who tried to identify and treat diseases during an outbreak in the aquarium. Finally, unresolved issues and important misconceptions regarding the field are discussed.
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Affiliation(s)
- Muhammed Duman
- Aquatic Animal Disease Department, Faculty of Veterinary Medicine, Bursa Uludag University, Bursa, Turkey
| | - Izzet Burçin Satıcıoğlu
- Aquatic Animal Disease Department, Faculty of Veterinary Medicine, Bursa Uludag University, Bursa, Turkey
| | - J Michael Janda
- Department of Public Health Services, Kern County, Bakersfield, California, USA
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Muangrerk C, Uchuwittayakul A, Srisapoome P. Identification, Expression and Antimicrobial Functional Analysis of Interleukin-8 (IL-8) in Response to Streptococcus iniae and Flavobacterium covae in Asian Seabass ( Lates calcarifer Bloch, 1790). Animals (Basel) 2024; 14:475. [PMID: 38338118 PMCID: PMC10854937 DOI: 10.3390/ani14030475] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Revised: 01/16/2024] [Accepted: 01/30/2024] [Indexed: 02/12/2024] Open
Abstract
In this research, the proinflammatory cytokine interleukin-8 (IL-8) was shown to play a key role in inflammatory responses in fish. This study involved the cloning of the gene that encodes IL-8 in Asian seabass (Lates calcarifer) as well as analyses of its expression and function in this fish. The expression levels of LcIL-8 indicated that it was broadly expressed in most analyzed tissues, with the most predominant expression in the whole blood 6 to 24 h after infection with S. iniae at concentrations of 105 colony-forming units (CFU)/fish (p < 0.05). After fish were immersed in F. covae, the LcIL-8 transcript was upregulated in the gills, liver and intestine, and the highest expression level was observed in the gills. However, LcIL-8 was downregulated in all the tested tissues at 48 and 96 h after infection with the two pathogenic strains, indicating that Lc-IL8 has a short half-life during the early immune responses to pathogens. Moreover, the MIC of the rLcIL-8 protein against S. iniae was 10.42 ± 3.61 µg/mL. Furthermore, functional analyses clearly demonstrated that 10 and 100 µg of the rLcIL-8 protein efficiently enhanced the phagocytic activity of Asian seabass phagocytes in vitro (p < 0.05). Additionally, in vivo injection of S. iniae following the rLcIL-8 protein indicated that 50 and 100 µg of rLc-IL-8 were highly effective in protecting fish from this pathogen (p < 0.001). The obtained results demonstrate that rLcIL-8 possesses a biological function in the defense against bacterial infections in Asian seabass.
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Affiliation(s)
- Chayanee Muangrerk
- Laboratory of Aquatic Animal Health Management, Department of Aquaculture, Faculty of Fisheries, Kasetsart University, 50 Paholayothin Road, Ladyao, Chatuchak, Bangkok 10900, Thailand; (C.M.); (A.U.)
- Center of Excellence in Aquatic Animal Health Management, Department of Aquaculture, Faculty of Fisheries, Kasetsart University, 50 Paholayothin Road, Ladyao, Chatuchak, Bangkok 10900, Thailand
| | - Anurak Uchuwittayakul
- Laboratory of Aquatic Animal Health Management, Department of Aquaculture, Faculty of Fisheries, Kasetsart University, 50 Paholayothin Road, Ladyao, Chatuchak, Bangkok 10900, Thailand; (C.M.); (A.U.)
- Center of Excellence in Aquatic Animal Health Management, Department of Aquaculture, Faculty of Fisheries, Kasetsart University, 50 Paholayothin Road, Ladyao, Chatuchak, Bangkok 10900, Thailand
| | - Prapansak Srisapoome
- Laboratory of Aquatic Animal Health Management, Department of Aquaculture, Faculty of Fisheries, Kasetsart University, 50 Paholayothin Road, Ladyao, Chatuchak, Bangkok 10900, Thailand; (C.M.); (A.U.)
- Center of Excellence in Aquatic Animal Health Management, Department of Aquaculture, Faculty of Fisheries, Kasetsart University, 50 Paholayothin Road, Ladyao, Chatuchak, Bangkok 10900, Thailand
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7
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Bergmann L, Balzer Le S, Hageskal G, Preuss L, Han Y, Astafyeva Y, Loevenich S, Emmann S, Perez-Garcia P, Indenbirken D, Katzowitsch E, Thümmler F, Alawi M, Wentzel A, Streit WR, Krohn I. New dienelactone hydrolase from microalgae bacterial community-Antibiofilm activity against fish pathogens and potential applications for aquaculture. Sci Rep 2024; 14:377. [PMID: 38172513 PMCID: PMC10764354 DOI: 10.1038/s41598-023-50734-9] [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: 07/27/2023] [Accepted: 12/24/2023] [Indexed: 01/05/2024] Open
Abstract
Biofilms are resistant to many traditional antibiotics, which has led to search for new antimicrobials from different and unique sources. To harness the potential of aquatic microbial resources, we analyzed the meta-omics datasets of microalgae-bacteria communities and mined them for potential antimicrobial and quorum quenching enzymes. One of the most interesting candidates (Dlh3), a dienelactone hydrolase, is a α/β-protein with predicted eight α-helices and eight β-sheets. When it was applied to one of the major fish pathogens, Edwardsiella anguillarum, the biofilm development was reproducibly inhibited by up to 54.5%. The transcriptome dataset in presence of Dlh3 showed an upregulation in functions related to self-defense like active genes for export mechanisms and transport systems. The most interesting point regarding the biotechnological potential for aquaculture applications of Dlh3 are clear evidence of biofilm inhibition and that health and division of a relevant fish cell model (CHSE-214) was not impaired by the enzyme.
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Affiliation(s)
- Lutgardis Bergmann
- Department of Microbiology and Biotechnology, Institute of Plant Science and Microbiology, University of Hamburg, Ohnhorststr.18, 22609, Hamburg, Germany
| | - Simone Balzer Le
- Department of Biotechnology and Nanomedicine, SINTEF Industry, Trondheim, Norway
| | - Gunhild Hageskal
- Department of Biotechnology and Nanomedicine, SINTEF Industry, Trondheim, Norway
| | - Lena Preuss
- Department of Microbiology and Biotechnology, Institute of Plant Science and Microbiology, University of Hamburg, Ohnhorststr.18, 22609, Hamburg, Germany
| | - Yuchen Han
- Department of Microbiology and Biotechnology, Institute of Plant Science and Microbiology, University of Hamburg, Ohnhorststr.18, 22609, Hamburg, Germany
| | - Yekaterina Astafyeva
- Department of Microbiology and Biotechnology, Institute of Plant Science and Microbiology, University of Hamburg, Ohnhorststr.18, 22609, Hamburg, Germany
| | - Simon Loevenich
- Department of Biotechnology and Nanomedicine, SINTEF Industry, Trondheim, Norway
| | - Sarah Emmann
- Molecular Microbiology, Institute for General Microbiology, Kiel University, Kiel, Germany
| | - Pablo Perez-Garcia
- Molecular Microbiology, Institute for General Microbiology, Kiel University, Kiel, Germany
| | | | - Elena Katzowitsch
- Core Unit Systems Medicine, University of Würzburg, Würzburg, Germany
| | - Fritz Thümmler
- Core Unit Systems Medicine, University of Würzburg, Würzburg, Germany
| | - Malik Alawi
- Bioinformatics Core, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Alexander Wentzel
- Department of Biotechnology and Nanomedicine, SINTEF Industry, Trondheim, Norway
| | - Wolfgang R Streit
- Department of Microbiology and Biotechnology, Institute of Plant Science and Microbiology, University of Hamburg, Ohnhorststr.18, 22609, Hamburg, Germany
| | - Ines Krohn
- Department of Microbiology and Biotechnology, Institute of Plant Science and Microbiology, University of Hamburg, Ohnhorststr.18, 22609, Hamburg, Germany.
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Ma YB, Zhou XQ, Jiang WD, Wu P, Liu Y, Li SW, Tang L, Zhang L, Mi HF, Feng L. Tea polyphenols protect against Flavobacterium columnare-induced gill injury via suppression of oxidative stress, inflammation, and apoptosis in grass carp. Int J Biol Macromol 2024; 254:127050. [PMID: 37742887 DOI: 10.1016/j.ijbiomac.2023.127050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2023] [Revised: 09/21/2023] [Accepted: 09/22/2023] [Indexed: 09/26/2023]
Abstract
Flavobacterium columnare (F. columnare) is one of the deadliest fish pathogens causing bacterial gill rot disease in various freshwater fish species globally. Tea polyphenols (TPs) are an inexpensive product extracted from tea that have received much attention as a feed additive in aquaculture. The current study was designed to investigate the underlying mechanisms and protective effects of dietary TPs against F. columnare-induced gill injury via suppression of oxidative stress, apoptosis, and inflammation in grass carp. TPs were not supplemented to the diet (control) and were supplemented at 40, 80, 120, 160 or 200 mg/kg diet. The feeding experiment was carried out for 60 days, followed by a 3-Day F. columnare challenge test. The results showed that 120 mg/kg TPs in the diet exerted the following five protective effects in fish gill: (1) control gill-rot disease and improved histopathology, (2) inhibit excessive apoptosis, (3) enhance the activity of antioxidant enzymes and upregulate related gene expression via the Nrf2/Keap1 pathway, (4) increase the activity of immune enzymes, And (5) mediate inflammatory cytokine gene expression via the JAK/STAT3 pathway. Taken together, dietary supplementation with TPs is a compelling approach to protect the gill function of fish against F. columnare.
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Affiliation(s)
- Yao-Bin Ma
- Animal Nutrition Institute, Sichuan Agricultural University, Chengdu, Sichuan 611130, China
| | - Xiao-Qiu Zhou
- Animal Nutrition Institute, Sichuan Agricultural University, Chengdu, Sichuan 611130, China; Fish Nutrition and Safety Production University Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, Sichuan 611130, China; Key Laboratory for Animal Disease-Resistance Nutrition of China Ministry of Education, Sichuan Agricultural University, Chengdu, Sichuan 611130, China
| | - Wei-Dan Jiang
- Animal Nutrition Institute, Sichuan Agricultural University, Chengdu, Sichuan 611130, China; Fish Nutrition and Safety Production University Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, Sichuan 611130, China; Key Laboratory for Animal Disease-Resistance Nutrition of China Ministry of Education, Sichuan Agricultural University, Chengdu, Sichuan 611130, China
| | - Pei Wu
- Animal Nutrition Institute, Sichuan Agricultural University, Chengdu, Sichuan 611130, China; Fish Nutrition and Safety Production University Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, Sichuan 611130, China; Key Laboratory for Animal Disease-Resistance Nutrition of China Ministry of Education, Sichuan Agricultural University, Chengdu, Sichuan 611130, China
| | - Yang Liu
- Animal Nutrition Institute, Sichuan Agricultural University, Chengdu, Sichuan 611130, China; Fish Nutrition and Safety Production University Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, Sichuan 611130, China; Key Laboratory for Animal Disease-Resistance Nutrition of China Ministry of Education, Sichuan Agricultural University, Chengdu, Sichuan 611130, China
| | - Shu-Wei Li
- Animal Nutrition Institute, Sichuan Academy of Animal Science, Sichuan Animtech Feed Co. Ltd, Chengdu 610066, Sichuan, China
| | - Ling Tang
- Animal Nutrition Institute, Sichuan Academy of Animal Science, Sichuan Animtech Feed Co. Ltd, Chengdu 610066, Sichuan, China
| | - Lu Zhang
- Tongwei Co., Ltd., Healthy Aquaculture Key Laboratory of Sichuan Province, Chengdu, Sichuan 610041, China
| | - Hai-Feng Mi
- Tongwei Co., Ltd., Healthy Aquaculture Key Laboratory of Sichuan Province, Chengdu, Sichuan 610041, China
| | - Lin Feng
- Animal Nutrition Institute, Sichuan Agricultural University, Chengdu, Sichuan 611130, China; Fish Nutrition and Safety Production University Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, Sichuan 611130, China; Key Laboratory for Animal Disease-Resistance Nutrition of China Ministry of Education, Sichuan Agricultural University, Chengdu, Sichuan 611130, China.
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9
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Zhang D, Zhou G, Thongda W, Li C, Ye Z, Zhao H, Beck BH, Mohammed H, Peatman E. Early divergent responses to virulent and attenuated vaccine isolates of Flavobacterium covae sp. nov. In channel catfish, Ictalurus punctatus. FISH & SHELLFISH IMMUNOLOGY 2024; 144:109248. [PMID: 38030028 DOI: 10.1016/j.fsi.2023.109248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 11/14/2023] [Accepted: 11/23/2023] [Indexed: 12/01/2023]
Abstract
Columnaris disease continues to inflict substantial losses among freshwater cultured species since its first description one hundred years ago. The experimental and anecdotal evidence suggests an expanded range and rising virulence of columnaris worldwide due to the warming global climate. The channel catfish (Ictalurus punctatus) are particularly vulnerable to columnaris. A recently developed live attenuated vaccine (17-23) for Flavobacterium columnare (now Flavobacterium covae sp. nov.) demonstrated superior protection for vaccinated catfish against genetically diverse columnaris isolates. In this study, we aimed to elucidate the molecular mechanisms and patterns of immune evasion and host manipulation linked to virulence by comparing gene expression changes in the host after the challenge with a virulent (BGSF-27) or live attenuated F. covae sp. nov. vaccine (17-23). Thirty-day-old fry were accordingly challenged with either virulent or vaccine isolates. Gill tissues were collected at 0 h (control), 1 h, and 2 h post-infection, which are two critical time points in early host-pathogen interactions. Transcriptome profiling of the gill tissues revealed a larger number (518) of differentially expressed genes (DEGs) in vaccine-exposed fish than those exposed to the virulent pathogen (321). Pathway analyses suggested potent suppression of early host immune responses by the virulent isolate through a higher expression of nuclear receptor corepressors (NCoR) responsible for antagonizing macrophage and T-cell signaling. Conversely, in vaccinated fry, we observed induction of Ca2+/calmodulin-dependent protein kinase II (CAMKII), responsible for clearing NCoR, and commensurate up-regulation of transcription factor AP-1 subunits, c-Fos, and c-Jun. As in mammalian systems, AP-1 expression was connected with a broad immune activation in vaccinated fry, including induction of CC chemokines, proteinases, iNOS, and IL-12b. Relatedly, divergent expression patterns of Src tyrosine kinase Lck, CD44, and CD28 indicated a delay or suppression of T-cell adhesion and activation in fry exposed to the virulent isolate. Broader implications of these findings will be discussed. The transcriptomic differences between virulent and attenuated bacteria may offer insights into how the host responds to the vaccination or infection and provide valuable knowledge to understand the early immune mechanisms of columnaris disease in aquaculture.
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Affiliation(s)
- Dongdong Zhang
- Hainan Provincial Key Laboratory for Tropical Hydrobiology and Biotechnology, School of Marine Bilology and Fisheries, Hainan University, Haikou, 570228, PR China; School of Fisheries, Aquaculture, and Aquatic Sciences, Auburn University, Auburn, AL, 36849, USA; College of Breeding and Multiplication (Sanya Institute of Breeding and Multiplication), Hainan University, Sanya, PR China
| | - Gengfu Zhou
- Hainan Provincial Key Laboratory for Tropical Hydrobiology and Biotechnology, School of Marine Bilology and Fisheries, Hainan University, Haikou, 570228, PR China
| | - Wilawan Thongda
- Center of Excellence for Shrimp Molecular Biology and Biotechnology (CENTEX Shrimp), Faculty of Science, Mahidol University, Bangkok, 10400, Thailand; National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), Pathum Thani, 12120, Thailand
| | - Chao Li
- School of Fisheries, Aquaculture, and Aquatic Sciences, Auburn University, Auburn, AL, 36849, USA
| | - Zhi Ye
- School of Fisheries, Aquaculture, and Aquatic Sciences, Auburn University, Auburn, AL, 36849, USA
| | - Honggang Zhao
- School of Fisheries, Aquaculture, and Aquatic Sciences, Auburn University, Auburn, AL, 36849, USA
| | - Benjamin H Beck
- United States Department of Agriculture, Agricultural Research Service, Aquatic Animal Health Research Unit, Auburn, AL, 36832, USA
| | - Haitham Mohammed
- School of Fisheries, Aquaculture, and Aquatic Sciences, Auburn University, Auburn, AL, 36849, USA
| | - Eric Peatman
- School of Fisheries, Aquaculture, and Aquatic Sciences, Auburn University, Auburn, AL, 36849, USA.
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Meachasompop P, Bunnoy A, Keaswejjareansuk W, Dechbumroong P, Namdee K, Srisapoome P. Development of Immersion and Oral Bivalent Nanovaccines for Streptococcosis and Columnaris Disease Prevention in Fry and Fingerling Asian Seabass ( Lates calcarifer) Nursery Farms. Vaccines (Basel) 2023; 12:17. [PMID: 38250830 PMCID: PMC10818643 DOI: 10.3390/vaccines12010017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Revised: 12/15/2023] [Accepted: 12/21/2023] [Indexed: 01/23/2024] Open
Abstract
In the present study, chitosan-based bivalent nanovaccines of S. iniae and F. covae were administered by immersion vaccination at 30 and 40 days after hatching (DAH), and the third vaccination was orally administered by feeding at 50 DAH. ELISA revealed that the levels of total IgM and specific IgM to S. iniae and F. covae were significantly elevated in all vaccinated groups at 10, 20, and 30 days after vaccination (DAV). A qRT-PCR analysis of immune-related genes revealed significantly higher IgT expression in the vaccinated groups compared to the control group, as revealed by 44-100-fold changes in the vaccinated groups compared to the control (p < 0.001) at every tested time point after vaccination. All vaccinated groups expressed IgM, MHCIIα, and TCRα at significantly higher levels than the control group at 10 and/or 20 DAV (p < 0.05). In the S. iniae challenge tests, the survival of vaccinated groups ranged from 62.15 ± 2.11 to 75.70 ± 3.36%, which significantly differed from that of the control group (44.44 ± 1.92%). Similarly, all vaccinated groups showed higher survival rates of 68.89 ± 3.85 to 77.78 ± 5.09% during F. covae challenge than the control groups (50.00 ± 3.33%) (p < 0.05).
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Affiliation(s)
- Pakapon Meachasompop
- Laboratory of Aquatic Animal Health Management, Department of Aquaculture, Faculty of Fisheries, Kasetsart University, 50 Paholayothin Rd., Ladyao, Chatuchak, Bangkok 10900, Thailand; (P.M.); (A.B.)
- Center of Excellence in Aquatic Animal Health Management, Faculty of Fisheries, Kasetsart University, 50 Paholayothin Rd., Ladyao, Chatuchak, Bangkok 10900, Thailand
| | - Anurak Bunnoy
- Laboratory of Aquatic Animal Health Management, Department of Aquaculture, Faculty of Fisheries, Kasetsart University, 50 Paholayothin Rd., Ladyao, Chatuchak, Bangkok 10900, Thailand; (P.M.); (A.B.)
- Center of Excellence in Aquatic Animal Health Management, Faculty of Fisheries, Kasetsart University, 50 Paholayothin Rd., Ladyao, Chatuchak, Bangkok 10900, Thailand
| | - Wisawat Keaswejjareansuk
- National Nanotechnology Center (NANOTEC), National Science and Technology Development Agency (NSTDA), Thailand Science Park, Pathumthani 12120, Thailand; (W.K.); (P.D.); (K.N.)
| | - Piroonrat Dechbumroong
- National Nanotechnology Center (NANOTEC), National Science and Technology Development Agency (NSTDA), Thailand Science Park, Pathumthani 12120, Thailand; (W.K.); (P.D.); (K.N.)
| | - Katawut Namdee
- National Nanotechnology Center (NANOTEC), National Science and Technology Development Agency (NSTDA), Thailand Science Park, Pathumthani 12120, Thailand; (W.K.); (P.D.); (K.N.)
| | - Prapansak Srisapoome
- Laboratory of Aquatic Animal Health Management, Department of Aquaculture, Faculty of Fisheries, Kasetsart University, 50 Paholayothin Rd., Ladyao, Chatuchak, Bangkok 10900, Thailand; (P.M.); (A.B.)
- Center of Excellence in Aquatic Animal Health Management, Faculty of Fisheries, Kasetsart University, 50 Paholayothin Rd., Ladyao, Chatuchak, Bangkok 10900, Thailand
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11
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Razali SA, Shamsir MS, Ishak NF, Low CF, Azemin WA. Riding the wave of innovation: immunoinformatics in fish disease control. PeerJ 2023; 11:e16419. [PMID: 38089909 PMCID: PMC10712311 DOI: 10.7717/peerj.16419] [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: 05/25/2023] [Accepted: 10/17/2023] [Indexed: 12/18/2023] Open
Abstract
The spread of infectious illnesses has been a significant factor restricting aquaculture production. To maximise aquatic animal health, vaccination tactics are very successful and cost-efficient for protecting fish and aquaculture animals against many disease pathogens. However, due to the increasing number of immunological cases and their complexity, it is impossible to manage, analyse, visualise, and interpret such data without the assistance of advanced computational techniques. Hence, the use of immunoinformatics tools is crucial, as they not only facilitate the management of massive amounts of data but also greatly contribute to the creation of fresh hypotheses regarding immune responses. In recent years, advances in biotechnology and immunoinformatics have opened up new research avenues for generating novel vaccines and enhancing existing vaccinations against outbreaks of infectious illnesses, thereby reducing aquaculture losses. This review focuses on understanding in silico epitope-based vaccine design, the creation of multi-epitope vaccines, the molecular interaction of immunogenic vaccines, and the application of immunoinformatics in fish disease based on the frequency of their application and reliable results. It is believed that it can bridge the gap between experimental and computational approaches and reduce the need for experimental research, so that only wet laboratory testing integrated with in silico techniques may yield highly promising results and be useful for the development of vaccines for fish.
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Affiliation(s)
- Siti Aisyah Razali
- Faculty of Science and Marine Environment, Universiti Malaysia Terengganu, Kuala Nerus, Terengganu, Malaysia
- Biological Security and Sustainability Research Interest Group (BIOSES), Universiti Malaysia Terengganu, Kuala Nerus, Terengganu, Malaysia
| | - Mohd Shahir Shamsir
- Department of Biosciences, Faculty of Science, Universiti Teknologi Malaysia, Skudai, Johor, Malaysia
| | - Nur Farahin Ishak
- Faculty of Science and Marine Environment, Universiti Malaysia Terengganu, Kuala Nerus, Terengganu, Malaysia
| | - Chen-Fei Low
- Institute of Systems Biology (INBIOSIS), Universiti Kebangsaan Malaysia, Bangi, Selangor, Malaysia
| | - Wan-Atirah Azemin
- School of Biological Sciences, Universiti Sains Malaysia, Minden, Pulau Pinang, Malaysia
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12
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Kong W, Yang P, Ding G, Cheng G, Xu Z. Elucidating the dynamic immune responses within the ocular mucosa of rainbow trout ( Oncorhynchus mykiss) after infection with Flavobacterium columnare. Front Immunol 2023; 14:1288223. [PMID: 38077363 PMCID: PMC10702956 DOI: 10.3389/fimmu.2023.1288223] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Accepted: 10/26/2023] [Indexed: 12/18/2023] Open
Abstract
The eye of vertebrates is constantly faced with numerous challenges from aquatic or airborne pathogens. As a crucial first line of defense, the ocular mucosa (OM) protects the visual organ from external threats in vertebrates such as birds and mammals. However, the understanding of ocular mucosal immunity in early vertebrates, such as teleost fish, remains limited, particularly concerning their resistance to bacterial infections. To gain insights into the pivotal role of the OM in antibacterial immunity among teleost fish, we developed a bacterial infection model using Flavobacterium columnare in rainbow trout (Oncorhynchus mykiss). Here the qPCR and immunofluorescence results showed that F. columnare could invade trout OM, suggesting that the OM could be a primary target and barrier for the bacteria. Moreover, immune-related genes (il-6, il-8, il-11, cxcl10, nod1, il1-b, igm, igt, etc.) were upregulated in the OM of trout following F. columnare infection, as confirmed by qPCR, which was further proved through RNA-seq. The results of transcriptome analyses showed that bacterial infection critically triggers a robust immune response, including innate, and adaptive immune-related signaling pathways such as Toll-like, NOD-like, and C-type lectin receptor signaling pathway and immune network for IgA production, which underscores the immune role of the OM in bacterial infection. Interestingly, a substantial reduction in the expression of genes associated with visual function was observed after infection, indicating that bacterial infection could impact ocular function. Overall, our findings have unveiled a robust mucosal immune response to bacterial infection in the teleost OM for the first time, providing valuable insights for future research into the mechanisms and functions of ocular mucosal immunity in early vertebrate species.
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Affiliation(s)
- Weiguang Kong
- Key Laboratory of Breeding Biotechnology and Sustainable Aquaculture, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Peng Yang
- Key Laboratory of Breeding Biotechnology and Sustainable Aquaculture, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Guangyi Ding
- Key Laboratory of Breeding Biotechnology and Sustainable Aquaculture, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Gaofeng Cheng
- Department of Aquatic Animal Medicine, College of Fisheries, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Zhen Xu
- Key Laboratory of Breeding Biotechnology and Sustainable Aquaculture, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
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13
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Fiedler AW, Gundersen MS, Vo TP, Almaas E, Vadstein O, Bakke I. Phage therapy minimally affects the water microbiota in an Atlantic salmon (Salmo salar) rearing system while still preventing infection. Sci Rep 2023; 13:19145. [PMID: 37932331 PMCID: PMC10628140 DOI: 10.1038/s41598-023-44987-7] [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: 06/20/2023] [Accepted: 10/14/2023] [Indexed: 11/08/2023] Open
Abstract
Excessive usage of antibiotics threatens the bacterial diversity in the microbiota of animals. An alternative to antibiotics that has been suggested to not disturb the microbiota is (bacterio)phage therapy. In this study, we challenged germ-free and microbially colonized yolk sac fry of Atlantic salmon with Flavobacterium columnare and observed that the mere presence of a microbiota protected the fish against lethal infection. We then investigated the effect of phage- or oxytetracycline treatment on fish survival and rearing water bacterial community characteristics using 16S rRNA gene amplicon sequencing. Phage treatment led to an increased survival of F. columnare-challenged fish and reduced the relative amounts of the pathogen in the water microbiota. In the absence of F. columnare, phage treatment did not affect the composition or the α-diversity of the rearing water microbiota. In the presence of the phage's host, phage treatment induced minor changes to the bacterial community composition, without affecting the α-diversity. Surprisingly, oxytetracycline treatment had no observable effect on the water microbiota and did not reduce the relative abundance of F. columnare in the water. In conclusion, we showed that phage treatment prevents mortality while not negatively affecting the rearing water microbiota, thus suggesting that phage treatment may be a suitable alternative to antibiotics. We also demonstrated a protective effect of the microbiota in Atlantic salmon yolk sac fry.
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Affiliation(s)
- Alexander W Fiedler
- Department of Biotechnology and Food Science, Norwegian University of Science and Technology, 7491, Trondheim, Norway
| | - Madeleine S Gundersen
- Department of Biotechnology and Food Science, Norwegian University of Science and Technology, 7491, Trondheim, Norway
| | - Toan P Vo
- Department of Biotechnology and Food Science, Norwegian University of Science and Technology, 7491, Trondheim, Norway
| | - Eivind Almaas
- Department of Biotechnology and Food Science, Norwegian University of Science and Technology, 7491, Trondheim, Norway
| | - Olav Vadstein
- Department of Biotechnology and Food Science, Norwegian University of Science and Technology, 7491, Trondheim, Norway
| | - Ingrid Bakke
- Department of Biotechnology and Food Science, Norwegian University of Science and Technology, 7491, Trondheim, Norway.
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14
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Hassanien HA, Alrashada YN, Abbas AO, Abdelwahab AM. Dietary propolis complementation relieves the physiological and growth deterioration induced by Flavobacterium columnare infection in juveniles of common carp (Cyprinus carpio). PLoS One 2023; 18:e0292976. [PMID: 37831671 PMCID: PMC10575500 DOI: 10.1371/journal.pone.0292976] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Accepted: 10/03/2023] [Indexed: 10/15/2023] Open
Abstract
The current study was proposed to explore the role of dietary propolis (PR) supplementation in alleviating the negative effects of columnaris disease (CD) challenge on the growth performance, plasma biochemicals, antioxidant activity, stress indicators, and immunological reactions of common carp (Cyprinus carpio) fish. Five hundred forty common carp juveniles were evenly placed in thirty-six 100-L tanks and stocked for acclimatization to the lab conditions with a control diet within a started period of 14 days. Fish (average initial weight of 7.11±0.06 g) were randomly distributed into one of six treatment groups (6 replicate tanks × 15 fish per tank in each treatment group). Fish in the first group was assigned as a negative control without CD challenge or PR supplementation. Fish in the other five groups were challenged with CD by immersion of fish for 60 min into a 10-L water bath supplemented with 6×106 CFU/mL (median lethal dose, LD50) of pathogenic F. columnare bacteria. After infection, the fish were restored to their tanks and fed on a basal diet supplemented with PR at 0, 3, 6, 9, or 12 g/kg diet. The experimental period continued for 6 consecutive weeks in which the feed was introduced twice a day (8:00 and 15:00 h) at a rate of 2% of the fish biomass. Ten percent of water was siphoned and renewed after each meal every day, in addition to 50% of water refreshment after cleaning the tank every three days. The tanks were continuously aerated and provided with standard rearing conditions for carp fish (24.0±1.12°C, 7.7±0.22 pH, 6.3±0.16 mg/L O2, and 14L/10D photoperiod). The growth performance traits such as feed intake (FI), weight gain (WG), final weight (FW), specific growth rate (SGR), feed efficiency (FE), and cumulative mortality rates (CM) were recorded during the experimental period. At the end of the trial, blood samples were obtained from the fish to evaluate some plasma biochemicals, including aspartate aminotransaminase (AST), alanine aminotransferase (ALT), creatinine (CRE), alkaline phosphatase (ALP), and lactate dehydrogenase (LDH), antioxidant biomarkers, including total antioxidant capacity (TAOC), total superoxide dismutase (TSOD), reduced glutathione (rGSH), and catalase (CAT), stress indicators, including heterophil to lymphocyte (H/L) ratio, cortisol (COR), malondialdehyde (MDA), and myeloperoxidase (MPO), and immunological reactions, including peripheral blood leukocyte proliferation (PBLP), phagocytosis activity (PHG), lysozyme activity (LYS), alternative complement hemolytic action (ACH50), and total immunoglobulin concentration (TIG). In addition, samples of infected fish gills were taken to quantify the number of F. columnare in the PR-supplemented groups using the quantitative real-time polymerase chain reaction (qPCR) technique. The results showed that incorporating PR into the dietary ingredients of common carp has a protective effect against the challenge with F. columnare infection. There were linear and quadratic positive trends (P < 0.05) in most parameters of growth performance, plasma biochemicals, antioxidant activity, stress indicators, and immunological reactions with the increased PR-supplemented levels in the diet of infected fish. The best results were obtained when using PR at 9 g/kg in the diet, while higher levels (12 g/kg PR) showed an adverse trend in the evaluated parameters. The FI, WG, FW, SGR, and FE were improved by approximately 37, 104, 34, 73, and 49% in the fish treated with 9 g/kg PR compared to none-PR-infected fish. In addition, adding PR at the 9 g/kg diet level was the best dose that reduced the H/L ratio, COR, MDA, and MPO by about 14, 52, 48, and 29%, respectively, in the infected fish. Furthermore, the mortality rate was reduced by 94%, and the number of pathogenic bacteria cells adherent to the fish gills was lowered by 96% in the infected fish treated with 9 g/kg PR compared to none-PR infected fish. Our results concluded that dietary supplementation with 9 g/kg PR could be a promising nutritional approach for improving the growth performance, physiological profile, and health status of common carp fish, particularly when challenged with F. columnare or similar bacterial infections.
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Affiliation(s)
- Hesham A. Hassanien
- Department of Animal and Fish Production, College of Agriculture and Food Sciences, King Faisal University, Hofuf, AL-HASA, Saudi Arabia
- Animal Production Department, Faculty of Agriculture, Cairo University, Giza, Egypt
| | - Yousof N. Alrashada
- Department of Animal and Fish Production, College of Agriculture and Food Sciences, King Faisal University, Hofuf, AL-HASA, Saudi Arabia
| | - Ahmed O. Abbas
- Department of Animal and Fish Production, College of Agriculture and Food Sciences, King Faisal University, Hofuf, AL-HASA, Saudi Arabia
- Animal Production Department, Faculty of Agriculture, Cairo University, Giza, Egypt
| | - Abdelwahab M. Abdelwahab
- Department of Animal and Fish Production, College of Agriculture and Food Sciences, King Faisal University, Hofuf, AL-HASA, Saudi Arabia
- Department of Animal Production, Faculty of Agriculture, Fayoum University, Fayoum, Egypt
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15
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Deck CA, Salger SA, Reynolds HM, Tada MD, Severance ME, Ferket P, Egna HS, Fatema MK, Haque SM, Borski RJ. Nutritional programming in Nile tilapia (Oreochromis niloticus): Effect of low dietary protein on growth and the intestinal microbiome and transcriptome. PLoS One 2023; 18:e0292431. [PMID: 37792787 PMCID: PMC10550151 DOI: 10.1371/journal.pone.0292431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Accepted: 09/19/2023] [Indexed: 10/06/2023] Open
Abstract
Nutritional programming is the idea that early nutrient contributions can influence organismal structure or function and is documented in a variety of vertebrates, yet studies in fish are largely lacking. Tilapia are an important foodfish, with global production having increased rapidly since the 1990s. They exhibit high disease-resistance and grow well on formulated feeds which makes them an ideal aquaculture species, however incorporating high quality proteins into feeds can be costly. As feed constitutes 50-70% of total production costs in aquaculture, reducing protein content could curb these costs and increase revenue. Thus, we examined the effects of feeding Nile tilapia (O. niloticus) fry a restricted protein diet for the first 7-21 days on growth, gut microbial flora, and the intestinal transcriptome. Fish were fed either a 25% restricted or 48% control crude protein starter (ST) diet for up to 21 days and then switched to a 25% or 38% control crude protein growout (GO) diet. Fish fed a 25% ST diet for 14 days followed by a 38% GO diet had significantly higher lengths and weights and better feed efficiency than fish fed the control 48% ST and 38% GO diet after 56 days of culture. Growth of fry on the 25% ST, 7-day/38% GO and the 25% ST,7-day/25% GO diets did not differ from the those fed the control protein diets, while fish fed the 25% ST diet for 21 days had significantly lower growth and survival rates. We observed no significant differences in either alpha or beta diversity of the gut microbial flora between diets, however species richness (Shannon Index) was higher in fry fed the 25% protein ST diet regardless of the GO diet. Similarly, fish fed the 25% ST diet for 14 days followed by the 38% GO diet had minimal changes to the intestinal transcriptome relative to fish fed the control 48% ST and 38% GO diet. However, those fed 25% ST and GO diets for the entire 56 days exhibited substantial differences in the gut transcriptome from other groups showing gene expression profiles characteristic of detrimental changes to gut physiology, protein metabolism and immune function. Results suggest protein restriction for up to 14 days early in development leads to enhanced growth and feed efficiency with minimal effects on gut microbes or intestinal function. Protein restriction beyond this period appears detrimental to fish growth and health as underscored by expression of disease related genes and higher mortality rates.
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Affiliation(s)
- Courtney A. Deck
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, United States of America
| | - Scott A. Salger
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, United States of America
- School of Sciences, Barton College, Wilson, NC, United States of America
| | - Hannah M. Reynolds
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, United States of America
| | - Michael D. Tada
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, United States of America
| | - Madeline E. Severance
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, United States of America
| | - Peter Ferket
- Department of Poultry Science, North Carolina State University, Raleigh, NC, United States of America
| | - Hillary S. Egna
- Department of Fisheries and Wildlife, Oregon State University, Corvallis, OR, United States of America
| | - Mst. Kaniz Fatema
- Faculty of Fisheries, Bangladesh Agricultural University, Mymensingh, Bangladesh
| | - Shahroz M. Haque
- Faculty of Fisheries, Bangladesh Agricultural University, Mymensingh, Bangladesh
| | - Russell J. Borski
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, United States of America
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16
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Nhinh DT, Hoa DT, Giang NTH, Van Van K, Dang LT, Crumlish M, Dong HT, Hoai TD. Synergistic infection of Edwardsiella ictaluri and Flavobacterium oreochromis in cage cultured tilapia (Oreochromis sp.). JOURNAL OF FISH DISEASES 2023; 46:1125-1136. [PMID: 37410863 DOI: 10.1111/jfd.13832] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2023] [Revised: 06/27/2023] [Accepted: 06/29/2023] [Indexed: 07/08/2023]
Abstract
Widespread distribution of a highly pathogenic Edwardsiella ictaluri strain in farmed tilapia in northern Vietnam has recently been reported. The subsequent investigation noticed a disease outbreak occurred at five nearby tilapia farms with floating cages, in which the clinical signs of both edwardsiellosis and columnaris diseases were observed on the same infected fish and caused 65% to 85% fish mortality. Naturally diseased fish (n = 109) were sampled from the five infected farms for bacterial identification and conducting challenge tests. The two bacteria Edwardsiella ictaluri and Flavobacterium oreochromis were identified by a combination of biochemical tests, PCR and 16SrRNA sequencing methods. Experimental challenge tests on Nile tilapia resulted in the median lethal dose (LD50 ) of E. ictaluri and F. oreochromis at 70 CFU/fish by intraperitoneal (i.p.) injection and 3.6 × 106 CFU/mL by immersion, respectively. The experimentally co-infected challenged fish exposed to LD50 doses resulted in 83% ± 6% mortality, with the infected fish exhibiting clinical signs of both edwardsiellosis and columnaris diseases, mimicking the naturally diseased fish. This finding suggests that the co-infection of E. ictaluri and F. oreochromis may interact in a synergistic manner, to enhance the overall severity of the infection and elevates the need for efficient methods to control both pathogens.
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Affiliation(s)
- Doan Thi Nhinh
- Faculty of Fisheries, Vietnam National University of Agriculture, Hanoi, Vietnam
- Research Institute for Aquaculture No 1, Bac Ninh, Vietnam
| | - Dang Thi Hoa
- Faculty of Fisheries, Vietnam National University of Agriculture, Hanoi, Vietnam
| | - Nguyen Thi Huong Giang
- Faculty of Veterinary Medicine, Vietnam National University of Agriculture, Hanoi, Vietnam
| | - Kim Van Van
- Faculty of Fisheries, Vietnam National University of Agriculture, Hanoi, Vietnam
| | - Lua Thi Dang
- Research Institute for Aquaculture No 1, Bac Ninh, Vietnam
| | - Mags Crumlish
- Institute of Aquaculture, University of Stirling, Stirling, UK
| | - Ha Thanh Dong
- Department of Food, Aquaculture and Aquatic Resources Management, Agriculture and Bioresources, School of Environment, Resources & Development (SERD), Asian Institute of Technology (AIT), Klong Luang, Thailand
| | - Truong Dinh Hoai
- Faculty of Fisheries, Vietnam National University of Agriculture, Hanoi, Vietnam
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17
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Kim YS, Hwang EM, Jeong CM, Cha CJ. Flavobacterium psychrotrophum sp. nov. and Flavobacterium panacagri sp. nov., Isolated from Freshwater and Soil. J Microbiol 2023; 61:891-901. [PMID: 37851309 DOI: 10.1007/s12275-023-00081-1] [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: 06/28/2023] [Revised: 09/06/2023] [Accepted: 09/08/2023] [Indexed: 10/19/2023]
Abstract
Two novel bacterial strains CJ74T and CJ75T belonging to the genus Flavobacterium were isolated from freshwater of Han River and ginseng soil, South Korea, respectively. Strain CJ74T was Gram-stain-negative, aerobic, rod-shaped, non-motile, and non-flagellated, and did not produce flexirubin-type pigments. Strain CJ75T was Gram-stain-negative, aerobic, rod-shaped, motile by gliding, and non-flagellated, and produced flexirubin-type pigments. Both strains were shown to grow optimally at 30 °C in the absence of NaCl on R2A medium. Phylogenetic analysis based on 16S rRNA gene sequences showed that strains CJ74T and CJ75T belonged to the genus Flavobacterium and were most closely related to Flavobacterium niveum TAPW14T and Flavobacterium foetidum CJ42T with 96.17% and 97.29% 16S rRNA sequence similarities, respectively. Genomic analyses including the reconstruction of phylogenomic tree, average nucleotide identity, and digital DNA-DNA hybridization suggested that they were novel species of the genus Flavobacterium. Both strains contained menaquinone 6 (MK-6) as the primary respiratory quinone and phosphatidylethanolamine as a major polar lipid. The predominant fatty acids of both strains were iso-C15:0 and summed feature 3 (C16:1 ω7c and/or C16:1 ω6c). Based on the polyphasic taxonomic study, strains CJ74T and CJ75T represent novel species of the genus Flavobacterium, for which names Flavobacterium psychrotrophum sp. nov. and Flavobacterium panacagri sp. nov. are proposed, respectively. The type strains are CJ74T (=KACC 19819T =JCM 32889T) and CJ75T (=KACC 23149T =JCM 36132T).
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Affiliation(s)
- Yong-Seok Kim
- Department or Systems Biotechnology, Chung-Ang University, Anseong, 17546, Republic of Korea
| | - Eun-Mi Hwang
- Department or Systems Biotechnology, Chung-Ang University, Anseong, 17546, Republic of Korea
| | - Chang-Myeong Jeong
- Department or Systems Biotechnology, Chung-Ang University, Anseong, 17546, Republic of Korea
| | - Chang-Jun Cha
- Department or Systems Biotechnology, Chung-Ang University, Anseong, 17546, Republic of Korea.
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18
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Han R, Hong Y, Xu R, Guo W, Zhang M, Lu Z, Han Q, Mo Z, Dan X, Li Y. Genomic evidence of genetic diversity and functional evolution in Flavobacterium columnare. Front Microbiol 2023; 14:1240471. [PMID: 37840739 PMCID: PMC10568018 DOI: 10.3389/fmicb.2023.1240471] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 09/06/2023] [Indexed: 10/17/2023] Open
Abstract
Flavobacterium columnare is the causative agent of columnaris disease in freshwater fish. Columnaris disease can cause heavy economic losses in aquaculture. In this study, whole-genome sequencing was used to characterize this pathogen. F. columnare isolate AH-01 had a circular chromosome and plasmid that encoded a total of 3,022 genes. Isolate GX-01 only had a circular chromosome and encoded 2,965 genes. Genomic islands, prophage regions, and CRISPR/Cas systems were identified in both genomes. Both genomes presented evidence of gene variation and horizontal transfer, both of which are the essential components of genetic diversity, genome plasticity, and functional evolution. Single-gene phylogeny and comparative genome analyses were performed to investigate the variation and evolution of this pathogen. Genetic analysis of 16S rRNA and housekeeping gene sequences significantly clustered 55 F. columnare isolates into four clades. The intragroup identity of the 16S rRNA gene exceeded 99%, while the intergroup identity was below the species delineation threshold. We discovered significant translocation, inversion, and rearrangement events that influenced local synteny within each group. Notably, the observed alignments varied considerably among all the studied groups. The core genomes of all strains with available sequences comprised 747 genes, corresponding to approximately 25% of the genome. Core genome multilocus sequence typing, genome-wide orthology and phylogenetic analyses, and average nucleotide identity suggested that the currently existing F. columnare was an assemblage of several distinct species, with levels of divergence at least equivalent to those between recognized bacterial species. The present investigation provided genomic evidence of gene variation and horizontal transfer, which were the basis of genetic diversity, genome plasticity, and functional evolution. The findings supported a proposed new taxonomic perspective on F. columnare.
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Affiliation(s)
- Rui Han
- University Joint Laboratory of Guangdong Province, Hong Kong and Macao Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, China
- Nansha-South China Agricultural University Fishery Research Institute, Guangzhou, China
| | - Yuhao Hong
- University Joint Laboratory of Guangdong Province, Hong Kong and Macao Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, China
| | - Ruilong Xu
- University Joint Laboratory of Guangdong Province, Hong Kong and Macao Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, China
| | - Wenjie Guo
- University Joint Laboratory of Guangdong Province, Hong Kong and Macao Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, China
| | - Mingshu Zhang
- School of Bioscience and Bioengineering, South China University of Technology, Guangzhou, China
| | - Zijun Lu
- University Joint Laboratory of Guangdong Province, Hong Kong and Macao Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, China
| | - Qing Han
- Guangdong Key Laboratory of Animal Conservation and Resource Utilization, Guangdong Public Laboratory of Wild Animal Conservation and Utilization, Institute of Zoology, Guangdong Academy of Sciences, Guangzhou, China
| | - Zequan Mo
- University Joint Laboratory of Guangdong Province, Hong Kong and Macao Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, China
- Nansha-South China Agricultural University Fishery Research Institute, Guangzhou, China
| | - Xueming Dan
- University Joint Laboratory of Guangdong Province, Hong Kong and Macao Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, China
- Nansha-South China Agricultural University Fishery Research Institute, Guangzhou, China
| | - Yanwei Li
- University Joint Laboratory of Guangdong Province, Hong Kong and Macao Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, China
- Nansha-South China Agricultural University Fishery Research Institute, Guangzhou, China
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19
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Pan X, Raaijmakers JM, Carrión VJ. Importance of Bacteroidetes in host-microbe interactions and ecosystem functioning. Trends Microbiol 2023; 31:959-971. [PMID: 37173204 DOI: 10.1016/j.tim.2023.03.018] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 03/30/2023] [Accepted: 03/31/2023] [Indexed: 05/15/2023]
Abstract
Bacteroidetes are prevalent in soil ecosystems and are associated with various eukaryotic hosts, including plants, animals, and humans. The ubiquity and diversity of Bacteroidetes exemplify their impressive versatility in niche adaptation and genomic plasticity. Over the past decade, a wealth of knowledge has been obtained on the metabolic functions of clinically relevant Bacteroidetes, but much less attention has been given to Bacteroidetes living in close association with plants. To improve our understanding of the functional roles of Bacteroidetes for plants and other hosts, we review the current knowledge of their taxonomy and ecology, in particular their roles in nutrient cycling and host fitness. We highlight their environmental distribution, stress resilience, genomic diversity, and functional importance in diverse ecosystems, including, but not limited to, plant-associated microbiomes.
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Affiliation(s)
- Xinya Pan
- Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Droevendaalsesteeg 10, 6708, PB, Wageningen, The Netherlands; Institute of Biology, Leiden University, Sylviusweg 72, 2333, BE, Leiden, The Netherlands
| | - Jos M Raaijmakers
- Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Droevendaalsesteeg 10, 6708, PB, Wageningen, The Netherlands; Institute of Biology, Leiden University, Sylviusweg 72, 2333, BE, Leiden, The Netherlands
| | - Víctor J Carrión
- Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Droevendaalsesteeg 10, 6708, PB, Wageningen, The Netherlands; Institute of Biology, Leiden University, Sylviusweg 72, 2333, BE, Leiden, The Netherlands; Departamento de Microbiología, Facultad de Ciencias, Universidad de Málaga, Málaga, Spain; Department of Microbiology and Plant Protection, Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora", IHSM-UMA-CSIC, Málaga, Spain.
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20
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Fraslin C, Robledo D, Kause A, Houston RD. Potential of low-density genotype imputation for cost-efficient genomic selection for resistance to Flavobacterium columnare in rainbow trout (Oncorhynchus mykiss). Genet Sel Evol 2023; 55:59. [PMID: 37580697 PMCID: PMC10424455 DOI: 10.1186/s12711-023-00832-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Accepted: 07/26/2023] [Indexed: 08/16/2023] Open
Abstract
BACKGROUND Flavobacterium columnare is the pathogen agent of columnaris disease, a major emerging disease that affects rainbow trout aquaculture. Selective breeding using genomic selection has potential to achieve cumulative improvement of the host resistance. However, genomic selection is expensive partly because of the cost of genotyping large numbers of animals using high-density single nucleotide polymorphism (SNP) arrays. The objective of this study was to assess the efficiency of genomic selection for resistance to F. columnare using in silico low-density (LD) panels combined with imputation. After a natural outbreak of columnaris disease, 2874 challenged fish and 469 fish from the parental generation (n = 81 parents) were genotyped with 27,907 SNPs. The efficiency of genomic prediction using LD panels was assessed for 10 panels of different densities, which were created in silico using two sampling methods, random and equally spaced. All LD panels were also imputed to the full 28K HD panel using the parental generation as the reference population, and genomic predictions were re-evaluated. The potential of prioritizing SNPs that are associated with resistance to F. columnare was also tested for the six lower-density panels. RESULTS The accuracies of both imputation and genomic predictions were similar with random and equally-spaced sampling of SNPs. Using LD panels of at least 3000 SNPs or lower-density panels (as low as 300 SNPs) combined with imputation resulted in accuracies that were comparable to those of the 28K HD panel and were 11% higher than the pedigree-based predictions. CONCLUSIONS Compared to using the commercial HD panel, LD panels combined with imputation may provide a more affordable approach to genomic prediction of breeding values, which supports a more widespread adoption of genomic selection in aquaculture breeding programmes.
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Affiliation(s)
- Clémence Fraslin
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, UK.
| | - Diego Robledo
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, UK
| | - Antti Kause
- Natural Resources Institute Finland (Luke), Myllytie 1, 31600, Jokioinen, Finland
| | - Ross D Houston
- Benchmark Genetics, Edinburgh Technopole, 1 Pioneer Building, Penicuik, EH26 0GB, UK
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21
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Guo W, Han R, Xu W, Lu Z, Li Y, Dan X, Mo Z. The protective effect of inactivated Flavobacterium columnare vaccine in grass carp ( Ctenopharyngodon idellus). Front Immunol 2023; 14:1162975. [PMID: 37520525 PMCID: PMC10381957 DOI: 10.3389/fimmu.2023.1162975] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Accepted: 06/27/2023] [Indexed: 08/01/2023] Open
Abstract
Flavobacterium columnare, which causes columnaris disease, is responsible for significant mortality in grass carp. Vaccination is a safe and effective measure to combat this disease, and this study aimed to investigate the immune protective effects of different treatments using an inactivated F. columnare vaccine. The vaccine was prepared by inactivating the bacteria with 0.05% formaldehyde at 4°C for 24 hours. The experiments involving grass carp were divided into two parts. In Experiment 1, the immune effects of two isolates, JX-01 (genomovar I) and MU-04 (genomovar II), were compared, along with the impact of white oil adjuvant and the number of immunizations. The results showed that when the white oil adjuvant was used as a booster, the relative percent survival (RPS) of the JW2 group and MW2 group after 8 weeks of the first immunization was 34% and 61%, respectively. In Experiment 2, only the MU-04 (genomovar II) isolate was used as an antigen, with the white oil adjuvant as a booster. The effects of different doses (CFU=108, 107, and 106 bacteria/mL) on immune responses were compared, and the RPS values in the MW6, MW7, and MW8 groups after 4 weeks of the first immunization were found to be 38%, 57%, and 71%, respectively. Furthermore, in the cross-antigen protection experiment, the MW2 group exhibited an RPS of 55% against the JX-01 isolate, which was significantly higher than the control group (33%). These findings suggest that an inactivated vaccine comprising an appropriate antigen isolate when administered with a white oil adjuvant as a booster, can provide effective protection in grass carp.
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Affiliation(s)
- Wenjie Guo
- University Joint Laboratory of Guangdong Province, Hong Kong and Macao Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, China
| | - Rui Han
- University Joint Laboratory of Guangdong Province, Hong Kong and Macao Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, China
| | - Weizhen Xu
- University Joint Laboratory of Guangdong Province, Hong Kong and Macao Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, China
| | - Zijun Lu
- University Joint Laboratory of Guangdong Province, Hong Kong and Macao Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, China
| | - Yanwei Li
- University Joint Laboratory of Guangdong Province, Hong Kong and Macao Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, China
| | - Xueming Dan
- University Joint Laboratory of Guangdong Province, Hong Kong and Macao Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, China
| | - Zequan Mo
- University Joint Laboratory of Guangdong Province, Hong Kong and Macao Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, China
- Henry Fok School of Biology and Agriculture, Shaoguan University, Shaoguan, China
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22
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Tuttle JT, Bruce TJ, Butts IAE, Roy LA, Abdelrahman HA, Beck BH, Kelly AM. Investigating the Ability of Edwardsiella ictaluri and Flavobacterium covae to Persist within Commercial Catfish Pond Sediments under Laboratory Conditions. Pathogens 2023; 12:871. [PMID: 37513718 PMCID: PMC10385248 DOI: 10.3390/pathogens12070871] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 05/26/2023] [Accepted: 06/22/2023] [Indexed: 07/30/2023] Open
Abstract
Two prevalent bacterial diseases in catfish aquaculture are enteric septicemia of catfish and columnaris disease caused by Edwardsiella ictaluri and Flavobacterium covae, respectively. Chronic and recurring outbreaks of these bacterial pathogens result in significant economic losses for producers annually. Determining if these pathogens can persist within sediments of commercial ponds is paramount. Experimental persistence trials (PT) were conducted to evaluate the persistence of E. ictaluri and F. covae in pond sediments. Twelve test chambers containing 120 g of sterilized sediment from four commercial catfish ponds were inoculated with either E. ictaluri (S97-773) or F. covae (ALG-00-530) and filled with 8 L of disinfected water. At 1, 2, 4-, 6-, 8-, and 15-days post-inoculation, 1 g of sediment was removed, and colony-forming units (CFU) were enumerated on selective media using 6 × 6 drop plate methods. E. ictaluri population peaked on Day 3 at 6.4 ± 0.5 log10 CFU g-1. Correlation analysis revealed no correlation between the sediment physicochemical parameters and E. ictaluri log10 CFU g-1. However, no viable F. covae colonies were recovered after two PT attempts. Future studies to improve understanding of E. ictaluri pathogenesis and persistence, and potential F. covae persistence in pond bottom sediments are needed.
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Affiliation(s)
- James T Tuttle
- Alabama Fish Farming Center, Greensboro, AL 36744, USA
- School of Fisheries, Aquaculture, and Aquatic Sciences, Auburn University, Auburn, AL 36849, USA
| | - Timothy J Bruce
- School of Fisheries, Aquaculture, and Aquatic Sciences, Auburn University, Auburn, AL 36849, USA
| | - Ian A E Butts
- School of Fisheries, Aquaculture, and Aquatic Sciences, Auburn University, Auburn, AL 36849, USA
| | - Luke A Roy
- Alabama Fish Farming Center, Greensboro, AL 36744, USA
- School of Fisheries, Aquaculture, and Aquatic Sciences, Auburn University, Auburn, AL 36849, USA
| | - Hisham A Abdelrahman
- Alabama Fish Farming Center, Greensboro, AL 36744, USA
- Department of Veterinary Hygiene and Management, Faculty of Veterinary Medicine, Cairo University, Giza 12211, Egypt
| | - Benjamin H Beck
- Aquatic Animal Health Research Unit, US Department of Agriculture, Agricultural Research Service, Auburn, AL 36832, USA
| | - Anita M Kelly
- Alabama Fish Farming Center, Greensboro, AL 36744, USA
- School of Fisheries, Aquaculture, and Aquatic Sciences, Auburn University, Auburn, AL 36849, USA
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23
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Sayed M, Narayanan L, Essa M, Lawrence M, Karsi A, Abdelhamed H. Secreted Extracellular Products of Flavobacterium covae as Potential Immunogenic Factors for Protection against Columnaris Disease in Channel Catfish ( Ictalurus punctatus). Pathogens 2023; 12:808. [PMID: 37375498 DOI: 10.3390/pathogens12060808] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 05/25/2023] [Accepted: 06/03/2023] [Indexed: 06/29/2023] Open
Abstract
Columnaris disease caused by Flavobacterium covae leads to substantial economic losses in commercially important fish species worldwide. The US channel catfish (Ictalurus punctatus) industry is particularly vulnerable to this disease. Therefore, there is an urgent need to develop a vaccine to reduce the economic losses caused by this disease. Secreted extracellular products (SEPs) are considered to be essential bacterial virulence factors that often provide immunogenicity and protection. The current study sought to identify the main SEPs of F. covae and to evaluate their potential to provide protection in channel catfish against columnaris disease. SDS-PAGE analysis of SEPs revealed five protein bands with molecular weights ranging from 13 to 99 kDa. Mass spectrometry analysis showed that these SEPs were hypothetical protein (AWN65_11950), zinc-dependent metalloprotease (AWN65_10205), DNA/RNA endonuclease G (AWN65_02330), outer membrane protein beta-barrel domain (AWN65_12620), and chondroitin-sulfate-ABC endolyase/exolyase (AWN65_08505). Catfish fingerlings were vaccinated with SEPs, SEPs emulsified with mineral oil adjuvant, or heat-inactivated SEPs, or they were sham-immunized through intraperitoneal (IP) injection. After 21 days, an F. covae challenge showed 58.77% and 46.17% survival in the catfish vaccinated with the SEPs and the SEPs emulsified with adjuvant compared to the sham-vaccinated control (100% mortality within 120 h post-infection). However, the heat-inactivated SEPs failed to provide significant protection (23.15% survival). In conclusion, although SEPs contain potentially important immunogenic proteins, further work is needed to optimize their use for long-lasting protection against columnaris disease in fish. These results are significant given the economic impact of columnaris disease on fish farming worldwide.
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Affiliation(s)
- Mohamed Sayed
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS 39762, USA
- Department of Fish Diseases and Management, Faculty of Veterinary Medicine, Beni-Suef University,Beni-Suef 62511, Egypt
| | - Lakshmi Narayanan
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS 39762, USA
| | - Manal Essa
- Department of Fish Diseases and Management, Faculty of Veterinary Medicine, Beni-Suef University,Beni-Suef 62511, Egypt
| | - Mark Lawrence
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS 39762, USA
| | - Attila Karsi
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS 39762, USA
| | - Hossam Abdelhamed
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS 39762, USA
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24
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The Infection Dynamics of Experimental Edwardsiella ictaluri and Flavobacterium covae Coinfection in Channel Catfish (Ictalurus punctatus). Pathogens 2023; 12:pathogens12030462. [PMID: 36986384 PMCID: PMC10051119 DOI: 10.3390/pathogens12030462] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Revised: 03/06/2023] [Accepted: 03/14/2023] [Indexed: 03/17/2023] Open
Abstract
Edwardsiella ictaluri and Flavobacterium covae are pervasive bacterial pathogens associated with significant losses in catfish aquaculture. Bacterial coinfections have the potential to increase outbreak severity and can worsen on-farm mortality. A preliminary assessment of in vivo bacterial coinfection with E. ictaluri (S97-773) and F. covae (ALG-00-530) was conducted using juvenile channel catfish (Ictalurus punctatus). Catfish were divided into five treatment groups: (1) mock control; (2) E. ictaluri full dose (immersion; 5.4 × 105 CFU mL−1); (3) F. covae full dose (immersion; 3.6 × 106 CFU mL−1); (4) E. ictaluri half dose (immersion; 2.7 × 105 CFU mL−1) followed by half dose F. covae (immersion; 1.8 × 106 CFU mL−1); and (5) F. covae half dose followed by half dose E. ictaluri. In the coinfection challenges, the second inoculum was delivered 48 h after the initial exposure. At 21 days post-challenge (DPC), the single dose E. ictaluri infection yielded a cumulative percent mortality (CPM) of 90.0 ± 4.1%, compared with 13.3 ± 5.9% in the F. covae group. Mortality patterns in coinfection challenges mimicked the single dose E. ictaluri challenge, with CPM of 93.3 ± 5.4% for fish initially challenged with E. ictaluri followed by F. covae, and 93.3 ± 2.7% for fish exposed to F. covae and subsequently challenged with E. ictaluri. Despite similarities in the final CPM within the coinfection groups, the onset of peak mortality was delayed in fish exposed to F. covae first but was congruent with mortality trends in the E. ictaluri challenge. Catfish exposed to E. ictaluri in both the single and coinfected treatments displayed increased serum lysozyme activity at 4-DPC (p < 0.001). Three pro-inflammatory cytokines (il8, tnfα, il1β) were evaluated for gene expression, revealing an increase in expression at 7-DPC in all E. ictaluri exposed treatments (p < 0.05). These data enhance our understanding of the dynamics of E. ictaluri and F. covae coinfections in US farm-raised catfish.
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25
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Burbick CR, Munson E, Lawhon SD, Zapp A, Villaflor M, Thelen E. An Update on Novel Taxa and Revised Taxonomic Status of Bacteria (Including Members of the Phylum Planctomycetota) Isolated from Aquatic Host Species Described in 2018 to 2021. J Clin Microbiol 2023; 61:e0142622. [PMID: 36719221 PMCID: PMC9945501 DOI: 10.1128/jcm.01426-22] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Increased interest in farmed aquatic species, aquatic conservation measures, and microbial metabolic end-product utilization have translated into a need for awareness and recognition of novel microbial species and revisions to bacterial taxonomy. Because this need has largely been unmet, through a 4-year literature review, we present lists of novel and revised bacterial species (including members of the phylum Planctomycetota) derived from aquatic hosts that can serve as a baseline for future biennial summaries of taxonomic revisions in this field. Most new and revised taxa were noted within oxidase-positive and/or nonglucose fermentative Gram-negative bacilli, including members of the Tenacibaculum, Flavobacterium, and Vibrio genera. Valid and effectively published novel members of the Streptococcus, Erysipelothrix, and Photobacterium genera are additionally described from disease pathogenesis perspectives.
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Affiliation(s)
- Claire R. Burbick
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, Washington, USA
| | - Erik Munson
- Department of Medical Laboratory Science, Marquette University, Milwaukee, Wisconsin, USA
| | - Sara D. Lawhon
- Department of Veterinary Pathobiology, Texas A&M University, College Station, Texas, USA
| | - Amanda Zapp
- Department of Medical Laboratory Science, Marquette University, Milwaukee, Wisconsin, USA
| | - Maia Villaflor
- Department of Medical Laboratory Science, Marquette University, Milwaukee, Wisconsin, USA
| | - Elizabeth Thelen
- Department of Medical Laboratory Science, Marquette University, Milwaukee, Wisconsin, USA
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26
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Irshath AA, Rajan AP, Vimal S, Prabhakaran VS, Ganesan R. Bacterial Pathogenesis in Various Fish Diseases: Recent Advances and Specific Challenges in Vaccine Development. Vaccines (Basel) 2023; 11:vaccines11020470. [PMID: 36851346 PMCID: PMC9968037 DOI: 10.3390/vaccines11020470] [Citation(s) in RCA: 27] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 02/08/2023] [Accepted: 02/15/2023] [Indexed: 02/22/2023] Open
Abstract
Aquaculture is a fast-growing food sector but is plagued by a plethora of bacterial pathogens that infect fish. The rearing of fish at high population densities in aquaculture facilities makes them highly susceptible to disease outbreaks, which can cause significant economic loss. Thus, immunity development in fish through vaccination against various pathogens of economically important aquaculture species has been extensively studied and has been largely accepted as a reliable method for preventing infections. Vaccination studies in aquaculture systems are strategically associated with the economically and environmentally sustainable management of aquaculture production worldwide. Historically, most licensed fish vaccines have been developed as inactivated pathogens combined with adjuvants and provided via immersion or injection. In comparison, live vaccines can simulate a whole pathogenic illness and elicit a strong immune response, making them better suited for oral or immersion-based therapy methods to control diseases. Advanced approaches in vaccine development involve targeting specific pathogenic components, including the use of recombinant genes and proteins. Vaccines produced using these techniques, some of which are currently commercially available, appear to elicit and promote higher levels of immunity than conventional fish vaccines. These technological advancements are promising for developing sustainable production processes for commercially important aquatic species. In this review, we explore the multitude of studies on fish bacterial pathogens undertaken in the last decade as well as the recent advances in vaccine development for aquaculture.
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Affiliation(s)
- Aadil Ahmed Irshath
- Department of Biomedical Sciences, School of Bio Sciences and Technology, Vellore Institute of Technology (VIT), Vellore 632 014, Tamil Nadu, India
| | - Anand Prem Rajan
- Department of Biomedical Sciences, School of Bio Sciences and Technology, Vellore Institute of Technology (VIT), Vellore 632 014, Tamil Nadu, India
- Correspondence: (A.P.R.); (R.G.)
| | - Sugumar Vimal
- Department of Biochemistry, Saveetha Medical College & Hospital, Saveetha Institute of Medical and Technical Sciences (SIMATS), Thandalam, Chennai 600 077, Tamilnadu, India
| | - Vasantha-Srinivasan Prabhakaran
- Department of Bioinformatics, Saveetha School of Engineering, Saveetha Institute of Medical and Technical Sciences (SIMATS), Chennai 600 077, Tamilnadu, India
| | - Raja Ganesan
- Institute for Liver and Digestive Diseases, College of Medicine, Hallym University, Chuncheon 24253, Republic of Korea
- Correspondence: (A.P.R.); (R.G.)
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27
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Shen R, Yu Y, Chen Z, Zhu M, Feng Y, Niu P, Yu S. Riemerella anatipestifer Endonuclease I displays enzymatic activity and is associated with bacterial virulence. Vet Microbiol 2023; 280:109700. [PMID: 36807978 DOI: 10.1016/j.vetmic.2023.109700] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 12/24/2022] [Accepted: 02/15/2023] [Indexed: 02/18/2023]
Abstract
Riemerella anatipestifer is an important pathogen of waterfowl, causing septicemic and exudative diseases. We previously reported that the R. anatipestifer AS87_RS02625 is a secretory protein of the type IX secretion system (T9SS). In this study, R. anatipestifer T9SS protein AS87_RS02625 was determined to be a functional Endonuclease I (EndoI), which has DNase and RNase activities. Optimal temperature and pH of the recombinant R. anatipestifer EndoI (rEndoI) to cleave λDNA were determined as 55-60 °C and 7.5 respectively. The DNase activity of the rEndoI was dependent on the presence of divalent metal ions. Presence of Mg2+ at a concentration range of 7.5-15 mM in the rEndoI reaction buffer displayed the highest DNase activity. In addition, the rEndoI displayed RNase activity to cleave MS2-RNA (ssRNA), either in the absence or presence of divalent cations Mg2+, Mn2+, Ca2+, Zn2+ and Cu2+. The DNase activity of the rEndoI was significantly enhanced by Mg2+, Mn2+ and Ca2+ but not Zn2+ and Cu2+. Moreover, we indicated that R. anatipestifer EndoI functioned on the bacterial adherence, invasion, in vivo survival and inducing inflammatory cytokines. These results indicate that the R. anatipestifer T9SS protein AS87_RS02625 is a novel EndoI, displays endonuclease activity and plays an important role in bacterial virulence.
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Affiliation(s)
- Ruyu Shen
- Jiangsu Agri-Animal Husbandry Vocational College, Veterinary Bio-Pharmaceutical, Jiangsu Key Laboratory for High-Tech Research and Development of Veterinary Biopharmaceuticals, Taizhou, Jiangsu, China; Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Shanghai 200241, China; College of Veterinary Medicine, Yangzhou University, Yangzhou 225000, China
| | - Yang Yu
- Jiangsu Agri-Animal Husbandry Vocational College, Veterinary Bio-Pharmaceutical, Jiangsu Key Laboratory for High-Tech Research and Development of Veterinary Biopharmaceuticals, Taizhou, Jiangsu, China
| | - Zongchao Chen
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Shanghai 200241, China
| | - Min Zhu
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Shanghai 200241, China
| | - Yating Feng
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Shanghai 200241, China; College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, China
| | - Pengfei Niu
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Shanghai 200241, China
| | - Shengqing Yu
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Shanghai 200241, China.
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28
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Thunes NC, Mohammed HH, Evenhuis JP, Lipscomb RS, Pérez-Pascual D, Stevick RJ, Birkett C, Conrad RA, Ghigo JM, McBride MJ. Secreted peptidases contribute to virulence of fish pathogen Flavobacterium columnare. Front Cell Infect Microbiol 2023; 13:1093393. [PMID: 36816589 PMCID: PMC9936825 DOI: 10.3389/fcimb.2023.1093393] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Accepted: 01/18/2023] [Indexed: 02/05/2023] Open
Abstract
Flavobacterium columnare causes columnaris disease in freshwater fish in both natural and aquaculture settings. This disease is often lethal, especially when fish population density is high, and control options such as vaccines are limited. The type IX secretion system (T9SS) is required for F. columnare virulence, but secreted virulence factors have not been fully identified. Many T9SS-secreted proteins are predicted peptidases, and peptidases are common virulence factors of other pathogens. T9SS-deficient mutants, such as ΔgldN and ΔporV, exhibit strong defects in secreted proteolytic activity. The F. columnare genome has many peptidase-encoding genes that may be involved in nutrient acquisition and/or virulence. Mutants lacking individual peptidase-encoding genes, or lacking up to ten peptidase-encoding genes, were constructed and examined for extracellular proteolytic activity, for growth defects, and for virulence in zebrafish and rainbow trout. Most of the mutants retained virulence, but a mutant lacking 10 peptidases, and a mutant lacking the single peptidase TspA exhibited decreased virulence in rainbow trout fry, suggesting that peptidases contribute to F. columnare virulence.
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Affiliation(s)
- Nicole C. Thunes
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI, United States
| | - Haitham H. Mohammed
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI, United States,Department of Rangeland, Wildlife and Fisheries Management, Texas A&M University, College Station, TX, United States
| | - Jason P. Evenhuis
- National Center for Cool and Cold Water Aquaculture, Agricultural Research Service, United States Department of Agriculture, Kearneysville, WV, United States
| | - Ryan S. Lipscomb
- National Center for Cool and Cold Water Aquaculture, Agricultural Research Service, United States Department of Agriculture, Kearneysville, WV, United States
| | - David Pérez-Pascual
- Institut Pasteur, Université de Paris-Cité, Centre National de la Recherche Scientifique (CNRS) Unité Mixte de Recherche (UMR) 6047, Genetics of Biofilms Laboratory, Paris, France
| | - Rebecca J. Stevick
- Institut Pasteur, Université de Paris-Cité, Centre National de la Recherche Scientifique (CNRS) Unité Mixte de Recherche (UMR) 6047, Genetics of Biofilms Laboratory, Paris, France
| | - Clayton Birkett
- National Center for Cool and Cold Water Aquaculture, Agricultural Research Service, United States Department of Agriculture, Kearneysville, WV, United States
| | - Rachel A. Conrad
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI, United States
| | - Jean-Marc Ghigo
- Institut Pasteur, Université de Paris-Cité, Centre National de la Recherche Scientifique (CNRS) Unité Mixte de Recherche (UMR) 6047, Genetics of Biofilms Laboratory, Paris, France
| | - Mark J. McBride
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI, United States,*Correspondence: Mark J. McBride,
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Bhatnagar A, Kumari S, Tyor AK. Assessment of bactericidal role of epidermal mucus of Heteropneustes fossilis and Clarias batrachus (Asian cat fishes) against pathogenic microbial strains. AQUACULTURE AND FISHERIES 2023. [DOI: 10.1016/j.aaf.2021.08.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Alterations of the Mucosal Immune Response and Microbial Community of the Skin upon Viral Infection in Rainbow Trout ( Oncorhynchus mykiss). Int J Mol Sci 2022; 23:ijms232214037. [PMID: 36430516 PMCID: PMC9698461 DOI: 10.3390/ijms232214037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2022] [Revised: 11/05/2022] [Accepted: 11/09/2022] [Indexed: 11/16/2022] Open
Abstract
The skin is the largest organ on the surface of vertebrates, which not only acts as the first line of defense against pathogens but also harbors diverse symbiotic microorganisms. The complex interaction between skin immunity, pathogens, and commensal bacteria has been extensively studied in mammals. However, little is known regarding the effects of viral infection on the skin immune response and microbial composition in teleost fish. In this study, we exposed rainbow trout (Oncorhynchus mykiss) to infectious hematopoietic necrosis virus (IHNV) by immersion infection. Through pathogen load detection and pathological evaluation, we confirmed that IHNV successfully invaded the rainbow trout, causing severe damage to the epidermis of the skin. qPCR analyses revealed that IHNV invasion significantly upregulated antiviral genes and elicited strong innate immune responses. Transcriptome analyses indicated that IHNV challenge induced strong antiviral responses mediated by pattern recognition receptor (PRR) signaling pathways in the early stage of the infection (4 days post-infection (dpi)), and an extremely strong antibacterial immune response occurred at 14 dpi. Our 16S rRNA sequencing results indicated that the skin microbial community of IHNV-infected fish was significantly richer and more diverse. Particularly, the infected fish exhibited a decrease in Proteobacteria accompanied by an increase in Actinobacteria. Furthermore, IHNV invasion favored the colonization of opportunistic pathogens such as Rhodococcus and Vibrio on the skin, especially in the later stage of infection, leading to dysbiosis. Our findings suggest that IHNV invasion is associated with skin microbiota dysbiosis and could thus lead to secondary bacterial infection.
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Conrad RA, Evenhuis JP, Lipscomb RS, Pérez-Pascual D, Stevick RJ, Birkett C, Ghigo JM, McBride MJ. Flavobacterium columnare ferric iron uptake systems are required for virulence. Front Cell Infect Microbiol 2022; 12:1029833. [PMID: 36325469 PMCID: PMC9618737 DOI: 10.3389/fcimb.2022.1029833] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2022] [Accepted: 09/28/2022] [Indexed: 11/24/2022] Open
Abstract
Flavobacterium columnare, which causes columnaris disease, is one of the costliest pathogens in the freshwater fish-farming industry. The virulence mechanisms of F. columnare are not well understood and current methods to control columnaris outbreaks are inadequate. Iron is an essential nutrient needed for metabolic processes and is often required for bacterial virulence. F. columnare produces siderophores that bind ferric iron for transport into the cell. The genes needed for siderophore production have been identified, but other components involved in F. columnare iron uptake have not been studied in detail. We identified the genes encoding the predicted secreted heme-binding protein HmuY, the outer membrane iron receptors FhuA, FhuE, and FecA, and components of an ATP binding cassette (ABC) transporter predicted to transport ferric iron across the cytoplasmic membrane. Deletion mutants were constructed and examined for growth defects under iron-limited conditions and for virulence against zebrafish and rainbow trout. Mutants with deletions in genes encoding outer membrane receptors, and ABC transporter components exhibited growth defects under iron-limited conditions. Mutants lacking multiple outer membrane receptors, the ABC transporter, or HmuY retained virulence against zebrafish and rainbow trout mirroring that exhibited by the wild type. Some mutants predicted to be deficient in multiple steps of iron uptake exhibited decreased virulence. Survivors of exposure to such mutants were partially protected against later infection by wild-type F. columnare.
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Affiliation(s)
- Rachel A. Conrad
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI, United States
| | - Jason P. Evenhuis
- National Center for Cool and Cold Water Aquaculture, Agricultural Research Service, United States Department of Agriculture (USDA), Kearneysville, WV, United States
| | - Ryan S. Lipscomb
- National Center for Cool and Cold Water Aquaculture, Agricultural Research Service, United States Department of Agriculture (USDA), Kearneysville, WV, United States
| | - David Pérez-Pascual
- Institut Pasteur, Université de Paris-Cité, CNRS UMR 6047, Genetics of Biofilms Laboratory, Paris, France
| | - Rebecca J. Stevick
- Institut Pasteur, Université de Paris-Cité, CNRS UMR 6047, Genetics of Biofilms Laboratory, Paris, France
| | - Clayton Birkett
- National Center for Cool and Cold Water Aquaculture, Agricultural Research Service, United States Department of Agriculture (USDA), Kearneysville, WV, United States
| | - Jean-Marc Ghigo
- Institut Pasteur, Université de Paris-Cité, CNRS UMR 6047, Genetics of Biofilms Laboratory, Paris, France
| | - Mark J. McBride
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI, United States
- *Correspondence: Mark J. McBride,
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Riemerella anatipestifer AS87_RS02955 Acts as a Virulence Factor and Displays Endonuclease Activity. Appl Environ Microbiol 2022; 88:e0127622. [PMID: 36106871 PMCID: PMC9552600 DOI: 10.1128/aem.01276-22] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Riemerella anatipestifer is an important bacterial pathogen in the global duck industry and causes heavy economic losses. In our previous study, we demonstrated that R. anatipestifer type IX secretion system components GldK and GldM, and the secretion protein metallophosphoesterase, acted as virulence factors. In this study, R. anatipestifer AS87_RS02955 was investigated for virulence and enzymatic activity properties. We constructed AS87_RS02955 mutation and complementation strains to assess bacterial virulence. In vivo bacterial loads showed a significantly reduced bacterial loads in the blood of ducks infected with mutant strain Yb2Δ02955, which was recovered in the blood of ducks infected with the complementation strain cYb2Δ02955, demonstrating that AS87_RS02955 was associated with virulence. Further studies showed AS87_RS02955 was a novel nonspecific endonuclease with no functionally conserved domain, but enzymatic activity toward DNA and RNA was indicated. DNase activity was activated by Zn2+, Cu2+, Mg2+, Ca2+, and Mn2+ ions but inhibited by ethylenediaminetetraacetic acid. RNase activity was independent of metal cations, but stimulated by Mg2+, Ca2+, and Mn2+. RAS87_RS02955 enzymatic activity was active across a broad pH and temperature range. Moreover, we identified four sites in rAS87_RS02955, F39, F92, I134, and F145, which were critical for enzymatic activity. In summary, we showed that R. anatipestifer AS87_RS02955 encoded a novel endonuclease with important roles in bacterial virulence. IMPORTANCE R. anatipestifer AS87_RS02955 was identified as a novel T9SS effector and displayed a nonspecific endonuclease activity in this study. The protein did not contain a conserved His-Asn-His motif structure, which is similar to the endonuclease from Prevotella sp. Its mutant strain Yb2Δ02955 demonstrated significantly attenuated virulence, suggesting AS87_RS02955 is an important virulence factor. Moreover, AS87_RS02955 displayed nonspecific endonuclease activity to cleave λ DNA and MS2 RNA, while four protein sites were critical for endonuclease activity. In conclusion, R. anatipestifer AS87_RS02955 plays important roles in bacterial virulence.
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Testerman T, Beka L, Reichley SR, King S, Welch TJ, Wiens GD, Graf J. A large-scale, multi-year microbial community survey of a freshwater trout aquaculture facility. FEMS Microbiol Ecol 2022; 98:6680245. [PMID: 36047934 DOI: 10.1093/femsec/fiac101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 07/15/2022] [Accepted: 08/30/2022] [Indexed: 12/14/2022] Open
Abstract
Aquaculture is an important tool for solving the growing worldwide food demand, but infectious diseases of farmed animals represent a serious roadblock to continued industry growth. Therefore, it is essential to understand the microbial communities that reside within the built environments of aquaculture facilities to identify reservoirs of bacterial pathogens and potential correlations between commensal species and specific disease agents. Here, we present the results from 3 years of sampling a commercial rainbow trout aquaculture facility. We observed that the microbial communities residing on the abiotic surfaces within the hatchery were distinct from those residing on the surfaces at the facility's water source as well as the production raceways, despite similar communities in the water column at each location. Also, a subset of the water community seeds the biofilm communities. Lastly, we detected a common fish pathogen, Flavobacterium columnare, within the hatchery, including at the source water inlet. Importantly, the relative abundance of this pathogen was correlated with clinical disease. Our results characterized the microbial communities in an aquaculture facility, established that the hatchery environment contains a unique community composition and demonstrated that a specific fish pathogen resides within abiotic surface biofilms and is seeded from the natural water source.
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Affiliation(s)
- Todd Testerman
- University of Connecticut, Department of Molecular and Cell Biology, Storrs, CT, 06269, USA
| | - Lidia Beka
- University of Connecticut, Department of Molecular and Cell Biology, Storrs, CT, 06269, USA
| | | | - Stacy King
- Riverence Provisions LLC, Buhl, ID 83316, USA
| | - Timothy J Welch
- National Center for Cool and Cold Water Aquaculture, Agricultural Research Service/U.S. Department of Agriculture, Kearneysville, WV, 25430, USA
| | - Gregory D Wiens
- National Center for Cool and Cold Water Aquaculture, Agricultural Research Service/U.S. Department of Agriculture, Kearneysville, WV, 25430, USA
| | - Joerg Graf
- University of Connecticut, Department of Molecular and Cell Biology, Storrs, CT, 06269, USA
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Conrad RA, Evenhuis JP, Lipscomb RS, Birkett C, McBride MJ. Siderophores Produced by the Fish Pathogen Flavobacterium columnare Strain MS-FC-4 Are Not Essential for Its Virulence. Appl Environ Microbiol 2022; 88:e0094822. [PMID: 35969053 PMCID: PMC9469716 DOI: 10.1128/aem.00948-22] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 07/29/2022] [Indexed: 01/17/2023] Open
Abstract
Flavobacterium columnare causes columnaris disease in wild and aquaculture-reared freshwater fish. F. columnare virulence mechanisms are not well understood, and current methods to control columnaris disease are inadequate. Iron acquisition from the host is important for the pathogenicity and virulence of many bacterial pathogens. F. columnare iron acquisition has not been studied in detail. We identified genes predicted to function in siderophore production for ferric iron uptake. Genes predicted to encode the proteins needed for siderophore synthesis, export, uptake, and regulation were deleted from F. columnare strain MS-FC-4. The mutants were examined for defects in siderophore production, for growth defects in iron-limited conditions, and for virulence against zebrafish and rainbow trout. Mutants lacking all siderophore activity were obtained. These mutants displayed growth defects when cultured under iron-limited conditions, but they retained virulence against zebrafish and rainbow trout similar to that exhibited by the wild type, indicating that the F. columnare MS-FC-4 siderophores are not required for virulence under the conditions tested. IMPORTANCE Columnaris disease, which is caused by Flavobacterium columnare, is a major problem for freshwater aquaculture. Little is known regarding F. columnare virulence factors, and control measures are limited. Iron acquisition mechanisms such as siderophores are important for virulence of other pathogens. We identified F. columnare siderophore biosynthesis, export, and uptake genes. Deletion of these genes eliminated siderophore production and resulted in growth defects under iron-limited conditions but did not alter virulence in rainbow trout or zebrafish. The results indicate that the F. columnare strain MS-FC-4 siderophores are not critical virulence factors under the conditions tested but may be important for survival under iron-limited conditions in natural aquatic environments or aquaculture systems.
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Affiliation(s)
- Rachel A. Conrad
- Department of Biological Sciences, University of Wisconsin–Milwaukee, Milwaukee, Wisconsin, USA
| | - Jason P. Evenhuis
- National Center for Cool and Cold Water Aquaculture, Agricultural Research Service, U.S. Department of Agriculture, Kearneysville, West Virginia, USA
| | - Ryan S. Lipscomb
- National Center for Cool and Cold Water Aquaculture, Agricultural Research Service, U.S. Department of Agriculture, Kearneysville, West Virginia, USA
| | - Clayton Birkett
- National Center for Cool and Cold Water Aquaculture, Agricultural Research Service, U.S. Department of Agriculture, Kearneysville, West Virginia, USA
| | - Mark J. McBride
- Department of Biological Sciences, University of Wisconsin–Milwaukee, Milwaukee, Wisconsin, USA
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35
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Zhang Y, Yang Z, Ni J, Ma Y, Xiong H, Jian W. Toxicity and modulation of silver nanoparticles synthesized using abalone viscera hydrolysates on bacterial community in aquatic environment. Front Microbiol 2022; 13:968650. [PMID: 36110292 PMCID: PMC9468672 DOI: 10.3389/fmicb.2022.968650] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Accepted: 08/10/2022] [Indexed: 11/13/2022] Open
Abstract
Polysaccharide decorated silver nanoparticles (AgNPs) are a new type of antibacterial agent in aquaculture, but their effects on the bacterial community structure in aquaculture water are still unknown. In this study, the primary hydrolysate from abalone (Haliotis discus hannai) viscera (AVH) was used to biosynthesize AVH-AgNPs by in situ reduction, and the crystallinity nature, size, morphology, and chemical composition were analyzed by high-resolution characterization techniques such as Ultraviolet–visible spectroscopy (UV–vis), X-rays diffraction (XRD), Transmission Electron Microscope (TEM), Dynamic light scattering (DLS), Zeta potential, inductively coupled plasma-optical emission spectrometry (ICP-OES) and Turbiscan stability index (TSI) values. Furthermore, the acute toxicity of AVH-AgNPs to zebrafish (Danio rerio) and their effects on bacterial community structure in fish culture water at low concentrations were studied. The results showed that the spherical AVH-AgNPs with an average diameter of 54.57 ± 12.96 nm had good stability, low toxicity, and good in vitro antibacterial activity. Within the experimental concentration range, all AVH-AgNPs treatments had decreased the bacterial diversity in zebrafish culture water to varying degrees. The bacteria with significantly decreased abundances were pathogenic or potential pathogenic, such as Aeromonas veronii, Flavobacterium columnare, and genera Flectobacillus and Bosea. The abundance of Haliscomenobacter sp. JS224, which might cause sludge swelling, also decreased significantly. On the other hand, the relative abundance of some bacterial taxa could remove xenobiotics (e.g., Runella defluvii and Phenylobacterium), control water eutrophication (Sediminibacterium), and reduce toxic algae proliferation (Candidatus Intestinusbacter nucleariae and Candidatus Finniella), increased significantly. Thus, the application of AVH-AgNPs in aquaculture water at low concentrations is relatively safe and has positive significance for improving the aquaculture environment. Also, AVH-AgNPs have good prospects in aquaculture.
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Affiliation(s)
- Yue Zhang
- Engineering Research Center of the Modern Technology for Eel Industry, Ministry of Education, Fisheries College of Jimei University, Xiamen, China
| | - Zhuan Yang
- Engineering Research Center of the Modern Technology for Eel Industry, Ministry of Education, Fisheries College of Jimei University, Xiamen, China
| | - Jing Ni
- Engineering Research Center of the Modern Technology for Eel Industry, Ministry of Education, Fisheries College of Jimei University, Xiamen, China
| | - Ying Ma
- Engineering Research Center of the Modern Technology for Eel Industry, Ministry of Education, Fisheries College of Jimei University, Xiamen, China
- *Correspondence: Ying Ma,
| | - Hejian Xiong
- College of Ocean Food and Biological Engineering, Jimei University, Xiamen, China
- Hejian Xiong,
| | - Wenjie Jian
- Institute of Respiratory Diseases, Xiamen Medical College, Xiamen, China
- Wenjie Jian,
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36
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Draft Genome Sequences of
Flavobacterium covae
Strains LSU-066-04 and LV-359-01. Microbiol Resour Announc 2022; 11:e0035222. [PMID: 35703564 PMCID: PMC9302162 DOI: 10.1128/mra.00352-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Flavobacterium covae is one of four Flavobacterium spp. that cause columnaris disease in teleost fish. Here, we report the draft genomes of two isolates, LSU-066-04 and LV-359-01, and their predicted virulence factors.
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37
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de Freitas Almeida GM, Hoikkala V, Ravantti J, Rantanen N, Sundberg LR. Mucin induces CRISPR-Cas defense in an opportunistic pathogen. Nat Commun 2022; 13:3653. [PMID: 35752617 PMCID: PMC9233685 DOI: 10.1038/s41467-022-31330-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Accepted: 06/14/2022] [Indexed: 01/21/2023] Open
Abstract
Parasitism by bacteriophages has led to the evolution of a variety of defense mechanisms in their host bacteria. However, it is unclear what factors lead to specific defenses being deployed upon phage infection. To explore this question, we co-evolved the bacterial fish pathogen Flavobacterium columnare and its virulent phage V156 in presence and absence of a eukaryotic host signal (mucin) for sixteen weeks. The presence of mucin leads to a dramatic increase in CRISPR spacer acquisition, especially in low nutrient conditions where over 60% of colonies obtain at least one new spacer. Additionally, we show that the presence of a competitor bacterium further increases CRISPR spacer acquisition in F. columnare. These results suggest that ecological factors are important in determining defense strategies against phages, and that the phage-bacterium interactions on mucosal surfaces may select for the diversification of bacterial immune systems.
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Affiliation(s)
- Gabriel Magno de Freitas Almeida
- University of Jyväskylä, Department of Biological and Environmental Science and Nanoscience Center, Jyväskylä, Finland
- Faculty of Biosciences, Fisheries and Economics, Norwegian College of Fishery Science, UiT The Arctic University of Norway, Tromsø, Norway
| | - Ville Hoikkala
- University of Jyväskylä, Department of Biological and Environmental Science and Nanoscience Center, Jyväskylä, Finland
| | - Janne Ravantti
- University of Helsinki, Molecular and Integrative Biosciences Research Programme, Helsinki, Finland
| | - Noora Rantanen
- University of Jyväskylä, Department of Biological and Environmental Science and Nanoscience Center, Jyväskylä, Finland
| | - Lotta-Riina Sundberg
- University of Jyväskylä, Department of Biological and Environmental Science and Nanoscience Center, Jyväskylä, Finland.
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de Freitas Almeida GM, Hoikkala V, Ravantti J, Rantanen N, Sundberg LR. Mucin induces CRISPR-Cas defense in an opportunistic pathogen. Nat Commun 2022; 13:3653. [PMID: 35752617 DOI: 10.1101/2021.08.10.455787v1.abstract] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Accepted: 06/14/2022] [Indexed: 05/27/2023] Open
Abstract
Parasitism by bacteriophages has led to the evolution of a variety of defense mechanisms in their host bacteria. However, it is unclear what factors lead to specific defenses being deployed upon phage infection. To explore this question, we co-evolved the bacterial fish pathogen Flavobacterium columnare and its virulent phage V156 in presence and absence of a eukaryotic host signal (mucin) for sixteen weeks. The presence of mucin leads to a dramatic increase in CRISPR spacer acquisition, especially in low nutrient conditions where over 60% of colonies obtain at least one new spacer. Additionally, we show that the presence of a competitor bacterium further increases CRISPR spacer acquisition in F. columnare. These results suggest that ecological factors are important in determining defense strategies against phages, and that the phage-bacterium interactions on mucosal surfaces may select for the diversification of bacterial immune systems.
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Affiliation(s)
- Gabriel Magno de Freitas Almeida
- University of Jyväskylä, Department of Biological and Environmental Science and Nanoscience Center, Jyväskylä, Finland
- Faculty of Biosciences, Fisheries and Economics, Norwegian College of Fishery Science, UiT The Arctic University of Norway, Tromsø, Norway
| | - Ville Hoikkala
- University of Jyväskylä, Department of Biological and Environmental Science and Nanoscience Center, Jyväskylä, Finland
| | - Janne Ravantti
- University of Helsinki, Molecular and Integrative Biosciences Research Programme, Helsinki, Finland
| | - Noora Rantanen
- University of Jyväskylä, Department of Biological and Environmental Science and Nanoscience Center, Jyväskylä, Finland
| | - Lotta-Riina Sundberg
- University of Jyväskylä, Department of Biological and Environmental Science and Nanoscience Center, Jyväskylä, Finland.
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Influence of Gallic Acid-Containing Mouth Spray on Dental Health and Oral Microbiota of Healthy Cats—A Pilot Study. Vet Sci 2022; 9:vetsci9070313. [PMID: 35878330 PMCID: PMC9325039 DOI: 10.3390/vetsci9070313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 06/14/2022] [Accepted: 06/20/2022] [Indexed: 11/22/2022] Open
Abstract
Simple Summary Periodontal diseases are common dental issues in cats. Oral care supplements were used to prevent diseases and maintain oral health. Moreover, maintaining a healthy oral microbiome is crucial for oral health. Therefore, we have developed a gallic acid-containing mouth spray and studied its effect on oral microbiota and dental health in healthy cats. The results revealed that the gingival and plaque indexes were improved after 42 days of mouth spray treatment in cats. The mouth spray treatment also reduced the abundance of harmful bacterial load and supported the growth of normal oral microbiota. This preliminary study recommended that the gallic acid-containing mouth spray could be an essential oral product to improve the oral hygiene of the cats. Abstract This pilot study aimed to investigate the effects of gallic acid-containing mouth spray on oral microbiota in healthy cat subjects. Forty healthy cats were recruited and randomly allocated to the control (G1; n = 20) and treatment groups (G2; n = 20). The cats were treated with mouth spray twice daily for 42 days. The changes in the gingival index (GI) and plaque index (PI) were measured at baseline (day 0) and end of the study (42nd day). The changes in the oral microbial composition of representative animals (control, n = 9; and treatment, n = 8) were also evaluated at baseline and end of the study. Oral microbial composition was assessed by amplifying the V1–V3 region of the 16S rRNA gene from supragingival dental plaque DNA extracts. The sequences were annotated using the QIIME 2.0. The GI and PI were significantly reduced after 42 days of treatment. The deep sequencing revealed that mouth spray influenced the cats’ oral microbiome and was significantly diverse. About 20 phyla and 59 species were observed after 42 days of mouth spray usage in cats’ oral microbiota. The number of operational taxonomic units (OTUs) of post-treatment samples (PoTS) of G2 was greatly reduced compared to other samples. Further analysis revealed that mouth spray acts substantially against Desulfomicrobium orale, one of the known pathogens in periodontal disease. The mouth spray efficiently reduced the growth of 22 species and uprooted 17 species. Moreover, the mouth spray supported the growth of normal oral microbiota, including Moraxella and Neisseria species. The preliminary study suggested that the gallic acids-containing mouth spray could be an essential oral product to improve the oral hygiene of the cats. Moreover, further studies are needed to confirm the beneficial effect of mouth spray on cats.
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40
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Description of Flavobacterium cyclinae sp. nov. and Flavobacterium channae sp. nov., isolated from the intestines of Cyclina sinensis (Corb shell) and Channa argus (Northern snakehead). J Microbiol 2022; 60:890-898. [DOI: 10.1007/s12275-022-2075-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 05/13/2022] [Accepted: 05/20/2022] [Indexed: 11/26/2022]
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Mocho JP, Collymore C, Farmer SC, Leguay E, Murray KN, Pereira N. FELASA-AALAS Recommendations for Monitoring and Reporting of Laboratory Fish Diseases and Health Status, with an Emphasis on Zebrafish ( Danio Rerio). Comp Med 2022; 72:127-148. [PMID: 35513000 PMCID: PMC9334007 DOI: 10.30802/aalas-cm-22-000034] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Accepted: 03/02/2022] [Indexed: 11/05/2022]
Abstract
The exchange of fish for research may expose an aquatic laboratory to pathogen contamination as incoming fish can introduce bacteria, fungi, parasites, and viruses capable of affecting both experimental results and fish and personnel health and welfare. To develop risk mitigation strategies, FELASA and AALAS established a joint working group to recommend good practices for health monitoring of laboratory fish. The recommendations address all fish species used for research, with a particular focus on zebrafish (Danio rerio). First, the background of the working group and key definitions are provided. Next, fish diseases of high impact are described. Third, recommendations are made for health monitoring of laboratory fishes. The recommendations emphasize the importance of daily observation of the fish and strategies to determine fish colony health status. Finally, report templates are proposed for historical screening data and aquatic facility description to facilitate biohazard risk assessment when exchanging fish.
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Affiliation(s)
| | - Chereen Collymore
- Veterinary Care and Services, Charles River Laboratories, Senneville, Quebec, Canada
| | - Susan C Farmer
- Zebrafish Research Facility, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | | | - Katrina N Murray
- Zebrafish International Resource Center, University of Oregon, Eugene, Oregon, USA
| | - Nuno Pereira
- Chronic Diseases Research Center (CEDOC), Nova Medical School, Lisbon; Faculty of Veterinary Medicine, Lusophone University of Humanities and Technologies, Lisbon, Portugal; Gulbenkian Institute of Science, Oeiras. Portugal; ISPA - University Institute of Psychological, Social and Life Sciences, Lisbon, Portugal; Lisbon Oceanarium, Lisbon, Portugal
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42
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Kaimal S, Farmer BD, Renukdas NN, Abdelrahman HA, Kelly AM. Evaluating Stress-Mediated Microbial Pathogenesis in Golden Shiners, Notemigonus crysoleucas. Front Physiol 2022; 13:886480. [PMID: 35634142 PMCID: PMC9132093 DOI: 10.3389/fphys.2022.886480] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Accepted: 04/11/2022] [Indexed: 11/22/2022] Open
Abstract
Flavobacterium covae (columnaris) is a microbial pathogen of the Golden Shiner (Notemigonus crysoleucas), a principal bait species. We investigated the effects of density and water temperature on the survival of fish subjected to a columnaris challenge and whether flow cytometry (FCM) could be a fast and reliable method to distinguish and enumerate F. covae populations from water and fish in experimental tanks. Juvenile Golden Shiners averaging 2.62 (±0.78 S.D.) g (negative for F. covae) were used in simultaneous trials at 22°C and 28°C in two ultra-low flow-through systems: each consisting of four treatments and five replicates per treatment. Treatments were fish stocked at either 600 fish/m3 or 2,400 fish/m3 and either challenged with F. covae or not; survival was observed for 48 h after challenge. Samples of water and fish tissue were obtained for FCM enumerations and validation by qPCR. No significant differences in survival were recorded between density treatments; however, high temperature and columnaris challenge treatments showed significantly higher mortality. Bacterial enumeration (number/mL) by FCM highly correlated with bacterial counts r = 0.81 (p = 0.001) in the water samples. Higher water temperatures may have increased columnaris infections and mortality in Golden Shiners. Flow cytometry is a reliable method of enumerating F. covae from experimental tank water samples.
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Affiliation(s)
- Sindhu Kaimal
- Department of Aquaculture and Fisheries, The University of Arkansas at Pine Bluff, Pine Bluff, AR, United States
| | - Bradley D. Farmer
- United States Department of Agriculture, Agriculture Research Service, Harry K. Dupree Stuttgart National Aquaculture Research Center, Stuttgart, AR, United States
| | - Nilima N. Renukdas
- Department of Aquaculture and Fisheries, The University of Arkansas at Pine Bluff, Pine Bluff, AR, United States
| | - Hisham A. Abdelrahman
- Department of Veterinary Hygiene and Management, Faculty of Veterinary Medicine, Cairo University, Giza, Egypt
- Alabama Fish Farming Center, Auburn University, Greensboro, AL, United States
| | - Anita M. Kelly
- Department of Aquaculture and Fisheries, The University of Arkansas at Pine Bluff, Pine Bluff, AR, United States
- *Correspondence: Anita M. Kelly,
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Runtuvuori‐Salmela A, Kunttu HMT, Laanto E, Almeida GMF, Mäkelä K, Middelboe M, Sundberg L. Prevalence of genetically similar Flavobacterium columnare phages across aquaculture environments reveals a strong potential for pathogen control. Environ Microbiol 2022; 24:2404-2420. [PMID: 35049114 PMCID: PMC9304149 DOI: 10.1111/1462-2920.15901] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 01/11/2022] [Indexed: 11/28/2022]
Abstract
Intensive aquaculture conditions expose fish to bacterial infections, leading to significant financial losses, extensive antibiotic use and risk of antibiotic resistance in target bacteria. Flavobacterium columnare causes columnaris disease in aquaculture worldwide. To develop a bacteriophage-based control of columnaris disease, we isolated and characterized 126 F. columnare strains and 63 phages against F. columnare from Finland and Sweden in 2017. Bacterial isolates were virulent on rainbow trout (Oncorhynchus mykiss) and fell into four previously described genetic groups A, C, E and G, with genetic groups C and E being the most virulent. Phage host range studied against a collection of 227 bacterial isolates (from 2013 to 2017) demonstrated modular infection patterns based on host genetic group. Phages infected contemporary and previously isolated bacterial hosts, but bacteria isolated most recently were generally resistant to previously isolated phages. Despite large differences in geographical origin, isolation year or host range of the phages, whole-genome sequencing of 56 phages showed high level of genetic similarity to previously isolated F. columnare phages (Ficleduovirus, Myoviridae). Altogether, this phage collection demonstrates a potential for use in phage therapy.
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Affiliation(s)
- Anniina Runtuvuori‐Salmela
- Department of Biological and Environmental Science and Nanoscience CenterUniversity of JyväskyläJyväskyläFinland
| | - Heidi M. T. Kunttu
- Department of Biological and Environmental Science and Nanoscience CenterUniversity of JyväskyläJyväskyläFinland
| | - Elina Laanto
- Department of Biological and Environmental Science and Nanoscience CenterUniversity of JyväskyläJyväskyläFinland
- Faculty of Biological and Environmental SciencesMolecular and Integrative Biosciences Research Programme, University of HelsinkiHelsinkiFinland
| | - Gabriel M. F. Almeida
- Department of Biological and Environmental Science and Nanoscience CenterUniversity of JyväskyläJyväskyläFinland
- Faculty of Biosciences, Fisheries and Economics, Norwegian College of Fishery ScienceUiT The Arctic University of NorwayTromsøNorway
| | - Kati Mäkelä
- Department of Biological and Environmental Science and Nanoscience CenterUniversity of JyväskyläJyväskyläFinland
| | - Mathias Middelboe
- Department of Biology, Marine Biological SectionUniversity of CopenhagenHelsingørDenmark
| | - Lotta‐Riina Sundberg
- Department of Biological and Environmental Science and Nanoscience CenterUniversity of JyväskyläJyväskyläFinland
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Pulkkinen K, Ketola T, Laakso J, Mappes J, Sundberg L. Rich resource environment of fish farms facilitates phenotypic variation and virulence in an opportunistic fish pathogen. Evol Appl 2022; 15:417-428. [PMID: 35386393 PMCID: PMC8965373 DOI: 10.1111/eva.13355] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 01/27/2022] [Accepted: 02/01/2022] [Indexed: 12/05/2022] Open
Abstract
Phenotypic variation is suggested to facilitate the persistence of environmentally growing pathogens under environmental change. Here, we hypothesized that the intensive farming environment induces higher phenotypic variation in microbial pathogens than natural environment, because of high stochasticity for growth and stronger survival selection compared to the natural environment. We tested the hypothesis with an opportunistic fish pathogen Flavobacterium columnare isolated either from fish farms or from natural waters. We measured growth parameters of two morphotypes from all isolates in different resource concentrations and two temperatures relevant for the occurrence of disease epidemics at farms and tested their virulence using a zebrafish (Danio rerio) infection model. According to our hypothesis, isolates originating from the fish farms had higher phenotypic variation in growth between the morphotypes than the isolates from natural waters. The difference was more pronounced in higher resource concentrations and the higher temperature, suggesting that phenotypic variation is driven by the exploitation of increased outside-host resources at farms. Phenotypic variation of virulence was not observed based on isolate origin but only based on morphotype. However, when in contact with the larger fish, the less virulent morphotype of some of the isolates also had high virulence. As the less virulent morphotype also had higher growth rate in outside-host resources, the results suggest that both morphotypes can contribute to F. columnare epidemics at fish farms, especially with current prospects of warming temperatures. Our results suggest that higher phenotypic variation per se does not lead to higher virulence, but that environmental conditions at fish farms could select isolates with high phenotypic variation in bacterial population and hence affect evolution in F. columnare at fish farms. Our results highlight the multifaceted effects of human-induced environmental alterations in shaping epidemiology and evolution in microbial pathogens.
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Affiliation(s)
- Katja Pulkkinen
- Department of Biological and Environmental ScienceUniversity of JyväskyläJyväskyläFinland
| | - Tarmo Ketola
- Department of Biological and Environmental ScienceUniversity of JyväskyläJyväskyläFinland
| | - Jouni Laakso
- Research Programme in Organismal and Evolutionary Biology, Faculty of Biological and Environmental Sciences, University of HelsinkiHelsinkiFinland
| | - Johanna Mappes
- Department of Biological and Environmental ScienceUniversity of JyväskyläJyväskyläFinland
- Research Programme in Organismal and Evolutionary Biology, Faculty of Biological and Environmental Sciences, University of HelsinkiHelsinkiFinland
| | - Lotta‐Riina Sundberg
- Department of Biological and Environmental ScienceUniversity of JyväskyläJyväskyläFinland
- Nanoscience CenterUniversity of JyväskyläJyväskyläFinland
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Testerman T, Beka L, McClure EA, Reichley SR, King S, Welch TJ, Graf J. Detecting Flavobacterial Fish Pathogens in the Environment via High-Throughput Community Analysis. Appl Environ Microbiol 2022; 88:e0209221. [PMID: 34788066 PMCID: PMC8788675 DOI: 10.1128/aem.02092-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2021] [Accepted: 11/09/2021] [Indexed: 11/20/2022] Open
Abstract
Diseases caused by the fish pathogens Flavobacterium columnare and Flavobacterium psychrophilum are major contributors of preventable losses in the aquaculture industry. The persistent and difficult-to-control infections caused by these bacteria make timely intervention and prophylactic elimination of pathogen reservoirs important measures to combat these disease-causing agents. In this study, we present two independent assays for detecting these pathogens in a range of environmental samples. Natural water samples were inoculated with F. columnare and F. psychrophilum over 5 orders of magnitude, and pathogen levels were detected using Illumina MiSeq sequencing and droplet digital PCR. Both detection methods accurately identified pathogen-positive samples and showed good agreement in quantifying each pathogen. Additionally, the real-world application of these approaches was demonstrated using environmental samples collected at a rainbow trout (Oncorhynchus mykiss) aquaculture facility. These results show that both methods can serve as useful tools for surveillance efforts in aquaculture facilities, where the early detection of these flavobacterial pathogens may direct preventative measures to reduce disease occurrence. IMPORTANCE Early detection of a deadly disease outbreak in a population can be the difference between mass mortality or mitigated effects. In the present study, we evaluated and compared two molecular techniques for detecting economically impactful aquaculture pathogens. We demonstrate that one of these techniques, 16S rRNA gene sequencing using Illumina MiSeq technology, provides the ability to accurately detect two freshwater fish pathogens, F. columnare and F. psychrophilum, while simultaneously profiling the native microbial community. The second technique, droplet digital PCR, is commonly used for pathogen detection, and the results obtained using the assays we designed with this method served to validate those obtained using the MiSeq method. These two methods offer distinct advantages. The MiSeq method pairs pathogen detection and microbial community profiling to answer immediate and long-term fish health concerns, while the droplet digital PCR method provides fast and highly sensitive detection that is useful for surveillance and rapid clinical responses.
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Affiliation(s)
- Todd Testerman
- University of Connecticut, Department of Molecular and Cell Biology, Storrs, Connecticut, USA
| | - Lidia Beka
- University of Connecticut, Department of Molecular and Cell Biology, Storrs, Connecticut, USA
| | - Emily Ann McClure
- University of Connecticut, Department of Molecular and Cell Biology, Storrs, Connecticut, USA
| | | | | | - Timothy J. Welch
- National Center for Cool and Cold Water Aquaculture, Agricultural Research Service/U.S. Department of Agriculture, Kearneysville, West Virginia, USA
| | - Joerg Graf
- University of Connecticut, Department of Molecular and Cell Biology, Storrs, Connecticut, USA
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Mekasha S, Linke D. Secretion Systems in Gram-Negative Bacterial Fish Pathogens. Front Microbiol 2022; 12:782673. [PMID: 34975803 PMCID: PMC8714846 DOI: 10.3389/fmicb.2021.782673] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Accepted: 11/24/2021] [Indexed: 12/17/2022] Open
Abstract
Bacterial fish pathogens are one of the key challenges in the aquaculture industry, one of the fast-growing industries worldwide. These pathogens rely on arsenal of virulence factors such as toxins, adhesins, effectors and enzymes to promote colonization and infection. Translocation of virulence factors across the membrane to either the extracellular environment or directly into the host cells is performed by single or multiple dedicated secretion systems. These secretion systems are often key to the infection process. They can range from simple single-protein systems to complex injection needles made from dozens of subunits. Here, we review the different types of secretion systems in Gram-negative bacterial fish pathogens and describe their putative roles in pathogenicity. We find that the available information is fragmented and often descriptive, and hope that our overview will help researchers to more systematically learn from the similarities and differences between the virulence factors and secretion systems of the fish-pathogenic species described here.
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Affiliation(s)
- Sophanit Mekasha
- Section for Genetics and Evolutionary Biology, Department of Biosciences, University of Oslo, Oslo, Norway
| | - Dirk Linke
- Section for Genetics and Evolutionary Biology, Department of Biosciences, University of Oslo, Oslo, Norway
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47
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Jiao C, Zou J, Chen Z, Zheng F, Xu Z, Lin YH, Wang Q. Dietary Glutamine Inclusion Regulates Immune and Antioxidant System, as Well as Programmed Cell Death in Fish to Protect against Flavobacterium columnare Infection. Antioxidants (Basel) 2021; 11:44. [PMID: 35052548 PMCID: PMC8773122 DOI: 10.3390/antiox11010044] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Revised: 12/23/2021] [Accepted: 12/24/2021] [Indexed: 01/07/2023] Open
Abstract
The susceptibility of animals to pathogenic infection is significantly affected by nutritional status. The present study took yellow catfish (Pelteobagrus fulvidraco) as a model to test the hypothesis that the protective roles of glutamine during bacterial infection are largely related to its regulation on the immune and antioxidant system, apoptosis and autophagy. Dietary glutamine supplementation significantly improved fish growth performance and feed utilization. After a challenge with Flavobacterium columnare, glutamine supplementation promoted il-8 and il-1β expression via NF-κB signaling in the head kidney and spleen, but inhibited the over-inflammation in the gut and gills. Additionally, dietary glutamine inclusion also enhanced the systematic antioxidant capacity. Histological analysis showed the protective role of glutamine in gill structures. Further study indicated that glutamine alleviated apoptosis during bacterial infection, along with the reduced protein levels of caspase-3 and the reduced expression of apoptosis-related genes. Moreover, glutamine also showed an inhibitory role in autophagy which was due to the increased activation of the mTOR signaling pathway. Thus, our study for the first time illustrated the regulatory roles of glutamine in the fish immune and antioxidant system, and reported its inhibitory effects on fish apoptosis and autophagy during bacterial infection.
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Affiliation(s)
- Congrui Jiao
- College of Fisheries, Huazhong Agricultural University, 1 Shizishan Street, Wuhan 430070, China; (C.J.); (J.Z.); (Z.C.); (F.Z.); (Z.X.)
| | - Jiahong Zou
- College of Fisheries, Huazhong Agricultural University, 1 Shizishan Street, Wuhan 430070, China; (C.J.); (J.Z.); (Z.C.); (F.Z.); (Z.X.)
| | - Zhenwei Chen
- College of Fisheries, Huazhong Agricultural University, 1 Shizishan Street, Wuhan 430070, China; (C.J.); (J.Z.); (Z.C.); (F.Z.); (Z.X.)
| | - Feifei Zheng
- College of Fisheries, Huazhong Agricultural University, 1 Shizishan Street, Wuhan 430070, China; (C.J.); (J.Z.); (Z.C.); (F.Z.); (Z.X.)
| | - Zhen Xu
- College of Fisheries, Huazhong Agricultural University, 1 Shizishan Street, Wuhan 430070, China; (C.J.); (J.Z.); (Z.C.); (F.Z.); (Z.X.)
| | - Yu-Hung Lin
- Department of Aquaculture, National Pingtung University of Science and Technology, 1 Shuefu Road, Neipu, Pingtung 912, Taiwan
| | - Qingchao Wang
- College of Fisheries, Huazhong Agricultural University, 1 Shizishan Street, Wuhan 430070, China; (C.J.); (J.Z.); (Z.C.); (F.Z.); (Z.X.)
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48
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LaFrentz BR, Králová S, Burbick CR, Alexander TL, Phillips CW, Griffin MJ, Waldbieser GC, García JC, de Alexandre Sebastião F, Soto E, Loch TP, Liles MR, Snekvik KR. The fish pathogen Flavobacterium columnare represents four distinct species: Flavobacterium columnare, Flavobacterium covae sp. nov., Flavobacterium davisii sp. nov. and Flavobacterium oreochromis sp. nov., and emended description of Flavobacterium columnare. Syst Appl Microbiol 2021; 45:126293. [PMID: 35026686 DOI: 10.1016/j.syapm.2021.126293] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 12/03/2021] [Accepted: 12/17/2021] [Indexed: 01/09/2023]
Abstract
Flavobacterium columnare is the causative agent of columnaris disease in freshwater fish and four discrete genetic groups exist within the species, suggesting that the species designation requires revision. The present study determined the taxonomic status of the four genetic groups of F. columnare using polyphasic and phylogenomic approaches and included five representative isolates from each genetic group (including type strain ATCC 23463T; genetic group 1). 16S rRNA gene sequence analysis revealed genetic group 2 isolate AL-02-36T, genetic group 3 isolate 90-106T, and genetic group 4 isolate Costa Rica 04-02-TNT shared less than <98.8 % sequence identity to F. columnare ATCC 23463T. Phylogenetic analyses of 16S rRNA and gyrB genes using different methodologies demonstrated the four genetic groups formed well-supported and distinct clades within the genus Flavobacterium. The average nucleotide identity (ANI) and digital DNA-DNA hybridization (GGDC) values between F. columnare ATCC 23463T, genetic group 2 isolate AL-02-36T, genetic group 3 isolate 90-106T, and genetic group 4 isolate Costa Rica 04-02-TNT were less than 90.84% and 42.7%, respectively. Biochemical and physiological characteristics were similar among the four genetic groups; however, quantitative differences in fatty acid profiles were detected and MALDI-TOF analyses demonstrated numerous distinguishing peaks unique to each genetic group. Chemotaxonomic, MALDI-TOF characterization and ANI/GGDC calculations afforded differentiation between the genetic groups, indicating each group is a discrete species. Herein, the names F. covae sp. nov. (AL-02-36T), F. davisii sp. nov. (90-106T), and F. oreochromis sp. nov. (Costa Rica 04-02-TNT) are proposed to represent genetic groups 2, 3, and 4, respectively.
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Affiliation(s)
- Benjamin R LaFrentz
- Aquatic Animal Health Research Unit, United States Department of Agriculture - Agricultural Research Service (USDA-ARS), Auburn, AL, United States.
| | - Stanislava Králová
- Department of Experimental Biology, Czech Collection of Microorganisms, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic; Department of Biological Sciences, Auburn University, Auburn, AL, United States
| | - Claire R Burbick
- Washington Animal Disease Diagnostic Laboratory, Pullman, WA, United States; Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA, United States
| | - Trevor L Alexander
- Washington Animal Disease Diagnostic Laboratory, Pullman, WA, United States
| | - Conner W Phillips
- Washington Animal Disease Diagnostic Laboratory, Pullman, WA, United States
| | - Matt J Griffin
- Department of Pathobiology and Population Medicine, College of Veterinary Medicine, Mississippi State University, Stoneville, MS, United States
| | - Geoffrey C Waldbieser
- Warmwater Aquaculture Research Unit, USDA-ARS, Thad Cochran National Warmwater Aquaculture Center, Stoneville, MS, United States
| | - Julio C García
- Aquatic Animal Health Research Unit, United States Department of Agriculture - Agricultural Research Service (USDA-ARS), Auburn, AL, United States
| | | | - Esteban Soto
- Department of Medicine & Epidemiology, School of Veterinary Medicine, University of California, Davis, CA, United States
| | - Thomas P Loch
- Department of Fisheries and Wildlife, College of Agriculture and Natural Resources, Department of Pathobiology and Diagnostic Investigation, College of Veterinary Medicine, Michigan State University, East Lansing, MI, United States
| | - Mark R Liles
- Department of Biological Sciences, Auburn University, Auburn, AL, United States
| | - Kevin R Snekvik
- Washington Animal Disease Diagnostic Laboratory, Pullman, WA, United States; Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA, United States
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49
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Type IX secretion system effectors and virulence of the model Flavobacterium columnare strain MS-FC-4. Appl Environ Microbiol 2021; 88:e0170521. [PMID: 34818105 DOI: 10.1128/aem.01705-21] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Flavobacterium columnare causes columnaris disease in wild and cultured freshwater fish and is a major problem for sustainable aquaculture worldwide. The F. columnare type IX secretion system (T9SS) secretes many proteins and is required for virulence. The T9SS component GldN is required for secretion and for gliding motility over surfaces. Genetic manipulation of F. columnare is inefficient, which has impeded identification of secreted proteins that are critical for virulence. Here we identified a virulent wild-type F. columnare strain (MS-FC-4) that is highly amenable to genetic manipulation. This facilitated isolation and characterization of two deletion mutants lacking core components of the T9SS. Deletion of gldN disrupted protein secretion and gliding motility and eliminated virulence in zebrafish and rainbow trout. Deletion of porV disrupted secretion and virulence but not motility. Both mutants exhibited decreased extracellular proteolytic, hemolytic, and chondroitin sulfate lyase activities. They also exhibited decreased biofilm formation and decreased attachment to fish fins and to other surfaces. Using genomic and proteomic approaches, we identified proteins secreted by the T9SS. We deleted ten genes encoding secreted proteins and characterized the virulence of mutants lacking individual or multiple secreted proteins. A mutant lacking two genes encoding predicted peptidases exhibited reduced virulence in rainbow trout, and mutants lacking a predicted cytolysin showed reduced virulence in zebrafish and rainbow trout. The results establish F. columnare strain MS-FC-4 as a genetically amenable model to identify virulence factors. This may aid development of measures to control columnaris disease and impact fish health and sustainable aquaculture. IMPORTANCE: Flavobacterium columnare causes columnaris disease in wild and aquaculture-reared freshwater fish and is a major problem for aquaculture. Little is known regarding the virulence factors involved in this disease and control measures are inadequate. The type IX secretion system (T9SS) secretes many proteins and is required for virulence, but the secreted virulence factors are not known. We identified a strain of F. columnare (MS-FC-4) that is well suited for genetic manipulation. The components of the T9SS and the proteins secreted by this system were identified. Deletion of core T9SS genes eliminated virulence. Genes encoding ten secreted proteins were deleted. Deletion of two peptidase-encoding genes resulted in decreased virulence in rainbow trout, and deletion of a cytolysin-encoding gene resulted in decreased virulence in rainbow trout and zebrafish. Secreted peptidases and cytolysins are likely virulence factors and are targets for the development of control measures.
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50
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Srisapoome P, Thummabancha K, Wongpanya R. Molecular Characterization and Defense Functions of the Nile Tilapia ( Oreochromis niloticus) DnaJ B9b and DnaJ C3a Genes in Response to Pathogenic Bacteria under High-Temperature Stress Conditions. Biomolecules 2021; 11:biom11101509. [PMID: 34680142 PMCID: PMC8533496 DOI: 10.3390/biom11101509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 10/05/2021] [Accepted: 10/10/2021] [Indexed: 11/16/2022] Open
Abstract
DnaJ proteins or heat shock protein 40s (HSP40s) form one of the largest heat shock protein families. In this study, 2 cDNAs encoding Nile tilapia (Oreochromis niloticus) DnaJ proteins (On-DnaJ B9b and On-DnaJ C3a) were successfully cloned and characterized. The structures and organizations of these two genes are first reported in the present study. On-DnaJ B9b is approximately 2.1 kb long and contains 2 exons and 1 intron, while On-DnaJ C3a is approximately 12 kb long and contains 12 exons and 11 introns. Under normal conditions, On-DnaJ B9b mRNA is highly expressed in gonad and trunk kidney tissues, while On-DnaJ C3a transcripts are abundantly expressed in gills, intestine, liver, and trunk kidney tissues. Following pathogenic infections, the expression of both genes is induced in the liver, spleen and head kidney tissues of Nile tilapia that were infected with two virulent pathogenic bacteria, Streptococcus agalactiae and Flavobacterium columnare. Silencing of these two genes was first carried out, and the results clearly indicated their crucial roles under both heat and bacterial stress conditions. The fundamental knowledge obtained from this study indicates the characteristic basic biofunctions of heat shock proteins in the regulation of intracellular proteins during infection, which involve preventing protein aggregation, promoting protein refolding, and activating unfolded protein degradation.
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Affiliation(s)
- Prapansak Srisapoome
- Laboratory of Aquatic Animal Health Management, Department of Aquaculture, Faculty of Fisheries, Kasetsart University, Chatuchak, Bangkok 10900, Thailand;
- Center of Advanced Studies for Agriculture and Food, Kasetsart University Institute for Advanced Studies, Kasetsart University, Bangkok 10900, Thailand
- Center of Excellence in Aquatic Animal Health Management, Faculty of Fisheries, Kasetsart University, Chatuchak, Bangkok 10900, Thailand
- Correspondence: ; Tel.: +66-2579-2924
| | - Kubpaphas Thummabancha
- Laboratory of Aquatic Animal Health Management, Department of Aquaculture, Faculty of Fisheries, Kasetsart University, Chatuchak, Bangkok 10900, Thailand;
- Center of Advanced Studies for Agriculture and Food, Kasetsart University Institute for Advanced Studies, Kasetsart University, Bangkok 10900, Thailand
- Center of Excellence in Aquatic Animal Health Management, Faculty of Fisheries, Kasetsart University, Chatuchak, Bangkok 10900, Thailand
| | - Ratree Wongpanya
- Department of Biochemistry, Faculty of Science, Kasetsart University, Bangkok 10900, Thailand;
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