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Swaminathan TR, Raj NS, Preena PG, Pradhan PK, Sood N, Kumar RG, Sudhagar A, Sood NK. Infectious spleen and kidney necrosis virus-associated large-scale mortality in farmed giant gourami, Osphronemus goramy, in India. JOURNAL OF FISH DISEASES 2021; 44:2043-2053. [PMID: 34449899 DOI: 10.1111/jfd.13519] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 08/09/2021] [Accepted: 08/10/2021] [Indexed: 06/13/2023]
Abstract
Megalocytivirus cause diseases that have serious economic impacts on aquaculture, mainly in East and South-East Asia. Five primary genotypes are known: infectious spleen and kidney necrosis virus (ISKNV), red sea bream iridovirus (RSIV), turbot reddish body iridovirus (TRBIV), threespine stickleback iridovirus (TSIV) and scale drop disease virus (SDDV). ISKNV-mediated infectious spleen and kidney necrosis disease (ISKND) is a major viral disease in both freshwater and marine fish species. In this study, we report the isolation of ISKNV from diseased giant gourami, Osphronemus goramy, in India. Transmission electron microscopy of ultrathin sections of kidney and spleen revealed the presence of numerous polygonal naked viral particles having an outer nucleocapsid layer within the cytoplasm of enlarged cells (115-125 nm). Molecular and phylogenetic analyses confirmed the presence of ISKNV and the major capsid protein (MCP) (1,362 bp) gene in the infected fish had a high similarity to the other ISKNV-I isolates. Moreover, ISKNV was propagated in the Astronotus ocellatus fin (AOF) cell line and further confirmed genotypically. A high mortality rate (60%) was observed in gourami fish injected with ISKNV-positive tissue homogenate through challenge studies. Considering the lethal nature of ISKNV, the present study spotlights the implementation of stringent biosecurity practices for the proper control of the disease in the country.
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Affiliation(s)
- Thangaraj Raja Swaminathan
- Peninsular and Marine Fish Genetic Resources Centre, ICAR-National Bureau of Fish Genetic Resources, CMFRI Campus, Kochi, India
| | - Nithianantham Sundar Raj
- Peninsular and Marine Fish Genetic Resources Centre, ICAR-National Bureau of Fish Genetic Resources, CMFRI Campus, Kochi, India
| | - Prasannan Geetha Preena
- Peninsular and Marine Fish Genetic Resources Centre, ICAR-National Bureau of Fish Genetic Resources, CMFRI Campus, Kochi, India
| | | | - Neeraj Sood
- ICAR- National Bureau of Fish Genetic Resources, Lucknow, India
| | - Rahul Girish Kumar
- Peninsular and Marine Fish Genetic Resources Centre, ICAR-National Bureau of Fish Genetic Resources, CMFRI Campus, Kochi, India
| | - Arun Sudhagar
- Peninsular and Marine Fish Genetic Resources Centre, ICAR-National Bureau of Fish Genetic Resources, CMFRI Campus, Kochi, India
| | - Naresh Kumar Sood
- Guru Angad Dev Veterinary and Animal Sciences University, Ludhiana, India
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Yadav MK, Pradhan PK, Sood N, Chaudhary DK, Verma DK, Chauhan U, Punia P, Jena JK. Innate immune response against an oomycete pathogen Aphanomyces invadans in common carp (Cyprinus carpio), a fish resistant to epizootic ulcerative syndrome. Acta Trop 2016; 155:71-6. [PMID: 26739655 DOI: 10.1016/j.actatropica.2015.12.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2015] [Revised: 12/14/2015] [Accepted: 12/16/2015] [Indexed: 10/22/2022]
Abstract
Infection with Aphanomyces invadans, also known as epizootic ulcerative syndrome, is a destructive disease of freshwater and brackishwater fishes. Although more than 130 species of fish have been confirmed to be susceptible to this disease, some of the commercially important fish species like common carp, milk fish and tilapia are reported to be resistant. Species that are naturally resistant to a particular disease, provide a potential model to study the mechanisms of resistance against that disease. In the present study, following experimental infection with A. invadans in common carp Cyprinus carpio, sequential changes in various innate immune parameters and histopathological alterations were monitored. Some of the studied innate immunity parameters viz. respiratory burst, alternative complement and total antiproteases activities of the infected common carp were higher compared to control fish, particularly at early stages of infection. On the other hand, some parameters such as myeloperoxidase, lysozyme and alpha-2 macroglobulin activities were not altered. Histopathological examination of the muscle at the site of injection revealed well developed granulomas at 12 days post infection, with subsequent regeneration of muscle fibers. From the results, it could be inferred that innate defense mechanisms of common carp are able to neutralize the virulence factors secreted by A. invadans, thereby, preventing its invasive spread and containing the infection. The results obtained here will help to better understand the mechanisms underlying resistance against A. invadans infection.
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Aguirre-Ayala D, Vidal-Martínez VM. Experimental Infection of the Mayan Cichlid Cichlasoma urophthalmus with the Oomycete Aphanomyces invadans. J Parasitol 2015; 101:485-7. [PMID: 25742055 DOI: 10.1645/14-589.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
This study aimed to determine the susceptibility of the Mayan cichlid Cichlasoma urophthalmus to infection with the fungus Aphanomyces invadans (also known as epizootic ulcerative syndrome [EUS]). A total of 27 C. urophthalmus were exposed to the original A. Invadans 2006/86/EC strain by intramuscularly injecting the fish with 25,000 zoospores/ml or exposing the fish to a suspension of 25,000 zoospores/ml in 6-L aquaria for 30 days. To assess the infectious capacity of A. invadans, 3 golden barbs (Puntius semifasciolatus) were infected intramuscularly with 200,000 zoospores/ml. A second experiment using 100 C. urophthalmus was performed for 60 days with 50 fish in each treatment group. A polymerase chain reaction (PCR)-based diagnostic method was used; muscle and gills were the target tissues. In the first experiment, none of the exposed C. urophthalmus developed skin lesions related to A. invadans infection. However, PCR analysis revealed that infection had occurred. For the intramuscular treatment, there were significant differences between the controls and the muscle samples (Fisher's exact test; P < 0.05) but not between the controls and the gill samples (P > 0.05). All golden barbs became infected, as indicated by PCR, and developed skin lesions typical of A. invadans infection. We concluded that C. urophthalmus was infected with A. invadans but was an asymptomatic carrier because skin lesions did not develop. In the second experiment, all fish were negative, suggesting that the fish had cleared the infection by the end of the experiment.
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Affiliation(s)
- Daniel Aguirre-Ayala
- Laboratorio de Patología Acuática. Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional CINVESTAV, Antigua Carretera a Progreso km 6 C.P. 97310, Mérida Yucatán, México
| | - Víctor Manuel Vidal-Martínez
- Laboratorio de Patología Acuática. Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional CINVESTAV, Antigua Carretera a Progreso km 6 C.P. 97310, Mérida Yucatán, México
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Yogeshwari G, Jagruthi C, Anbazahan SM, Mari LSS, Selvanathan J, Arockiaraj J, Dhayanithi NB, Ajithkumar TT, Balasundaram C, Ramasamy H. Herbal supplementation diet on immune response in Labeo rohita against Aphanomyces invadans. AQUACULTURE 2015; 437:351-359. [DOI: 10.1016/j.aquaculture.2014.12.024] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/16/2023]
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Yadav MK, Pradhan PK, Sood N, Chaudhary DK, Verma DK, Debnath C, Sahoo L, Chauhan UK, Punia P, Jena JK. Innate immune response of Indian major carp, Labeo rohita infected with oomycete pathogen Aphanomyces invadans. FISH & SHELLFISH IMMUNOLOGY 2014; 39:524-531. [PMID: 24945572 DOI: 10.1016/j.fsi.2014.06.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Revised: 06/08/2014] [Accepted: 06/09/2014] [Indexed: 06/03/2023]
Abstract
The fish pathogenic oomycete Aphanomyces invadans is the causative agent of epizootic ulcerative syndrome (EUS), a fish disease of international significance and reportable to the World Organisation for Animal Health. In spite of the current and potential impact of A. invadans infection on fisheries and aquaculture sectors of the world, very little is known about the host-A. invadans interactions. In the present study, following experimental infection with A. invadans in one of the Indian major carps, Labeo rohita, sequential changes in various innate immune parameters were monitored. The results indicated that at early stages of infection, no significant changes in any of the studied innate immune parameters were observed. However, at the advanced stages of infection from 6 to 12 days post infection (dpi), the respiratory burst and alternate complement activity were significantly higher whereas lysozyme, antiproteases and α-2 macroglobulin values were significantly lower than the control group and also from the infected group at earlier stages of infection. Since, the possibility of vaccination of fish against A. invadans appears remote due to difficulties in eliciting a specific antibody response, the information generated in the present study could be useful for developing strategies for improving resistance to A. invadans infection by stimulating the innate immunity through immunomodulation.
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Affiliation(s)
- Manoj K Yadav
- National Bureau of Fish Genetic Resources, Canal Ring Road, P.O. Dilkusha, Lucknow 226 002, Uttar Pradesh, India
| | - Pravata K Pradhan
- National Bureau of Fish Genetic Resources, Canal Ring Road, P.O. Dilkusha, Lucknow 226 002, Uttar Pradesh, India.
| | - Neeraj Sood
- National Bureau of Fish Genetic Resources, Canal Ring Road, P.O. Dilkusha, Lucknow 226 002, Uttar Pradesh, India
| | - Dharmendra K Chaudhary
- National Bureau of Fish Genetic Resources, Canal Ring Road, P.O. Dilkusha, Lucknow 226 002, Uttar Pradesh, India
| | - Dev K Verma
- National Bureau of Fish Genetic Resources, Canal Ring Road, P.O. Dilkusha, Lucknow 226 002, Uttar Pradesh, India
| | - Chandan Debnath
- ICAR Research Complex for North Eastern Hill Region, Lambucherra 799 210, Tripura, India
| | - Lopamudra Sahoo
- ICAR Research Complex for North Eastern Hill Region, Lambucherra 799 210, Tripura, India
| | - U K Chauhan
- School of Environmental Biology, Awadesh Pratap Singh University, Rewa 486 003, Madhya Pradesh, India
| | - Peyush Punia
- National Bureau of Fish Genetic Resources, Canal Ring Road, P.O. Dilkusha, Lucknow 226 002, Uttar Pradesh, India
| | - Joy K Jena
- National Bureau of Fish Genetic Resources, Canal Ring Road, P.O. Dilkusha, Lucknow 226 002, Uttar Pradesh, India
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de Bruijn I, Belmonte R, Anderson VL, Saraiva M, Wang T, van West P, Secombes CJ. Immune gene expression in trout cell lines infected with the fish pathogenic oomycete Saprolegnia parasitica. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2012; 38:44-54. [PMID: 22522286 DOI: 10.1016/j.dci.2012.03.018] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2012] [Revised: 03/30/2012] [Accepted: 03/30/2012] [Indexed: 05/31/2023]
Abstract
The oomycete Saprolegnia parasitica causes significant losses in the aquaculture industry, mainly affecting salmon, trout and catfish. Since the ban of malachite green, effective control measures are currently not available prompting a re-evaluation of the potential for immunological intervention. In this study, the immune response of salmonid cells is investigated at the transcript level, by analysis of a large set of immune response genes in four different rainbow trout cell lines (RTG-2, RTGill, RTL and RTS11) upon infection with S. parasitica. Proinflammatory cytokine transcripts were induced in all four cell lines, including IL-1β1, IL-8, IL-11, TNF-α2, as well as other components of the innate defences, including COX-2, the acute phase protein serum amyloid A and C-type lectin CD209a and CD209b. However, differences between the four cell lines were found. For example, the fold change of induction was much higher in the epithelial RTL and macrophage-like RTS11 cell lines compared to the fibroblast cell lines RTG-2 and RTGill. Several antimicrobial peptides (AMPs) were also up-regulated in response to Saprolegnia infection, including hepcidin and cathelicidin 1 (rtCATH1) and 2 (rtCATH2). An rtCATH2 peptide was synthesised and tested for activity and whilst it showed no killing activity for zoospores, it was able to delay sporulation of S. parasitica. These results demonstrate that particular immune genes are up-regulated in response to S. parasitica infection and that AMPs may play a crucial role in the first line of defence against oomycetes in fish.
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Affiliation(s)
- Irene de Bruijn
- Aberdeen Oomycete Laboratory, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, UK
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Sood N, Chaudhary DK, Rathore G, Singh A, Lakra WS. Monoclonal antibodies to snakehead, Channa striata immunoglobulins: detection and quantification of immunoglobulin-positive cells in blood and lymphoid organs. FISH & SHELLFISH IMMUNOLOGY 2011; 30:569-575. [PMID: 21167285 DOI: 10.1016/j.fsi.2010.12.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2010] [Revised: 12/01/2010] [Accepted: 12/03/2010] [Indexed: 05/30/2023]
Abstract
Snakehead Channa striata is an important freshwater food fish in many Southeast Asian countries. Three monoclonal antibodies (C9, C10 and D10) were developed against purified serum immunoglobulins of Channa striata (Cs-Ig) and characterized. C9 and D10 MAbs were specific to heavy chain, while C10 MAb detected only unreduced Cs-Ig in western blotting. In competitive ELISA, C9 and C10 MAbs were specific to C. striata Ig and showed no cross reactivity with serum Ig of other fish species i.e. Channa punctatus, Channa marulius, Clarias batrachus and Labeo rohita. D10 MAb showed reactivity to serum Ig of C. striata and C. marulius. In FACS analysis of gated lymphocytes, the percentage of Ig+ cells detected by C9 MAb was 18.2%, 27.7% and 10.3% in blood, spleen and kidney, respectively (n=3, body weight 500-600 g). However, only a few cells (0.5%) were found to be Ig+ in thymus (n=5). C9 MAb was also successfully employed to demonstrate Ig+ cells in blood smears and formalin fixed sections of spleen and kidney. These findings suggest that the spleen plays an important role in humoral immunity as compared to head kidney. Further, these MAbs can be useful immunological tool in monitoring health status of cultured C. striata.
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Affiliation(s)
- Neeraj Sood
- National Bureau of Fish Genetic Resources, Fish Health Management Division, Canal Ring Road, P.O. Dilkusha, Lucknow 226002, Uttar Pradesh, India.
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Interaction of Francisella asiatica with tilapia (Oreochromis niloticus) innate immunity. Infect Immun 2010; 78:2070-8. [PMID: 20160018 DOI: 10.1128/iai.01308-09] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Members of the genus Francisella are facultative intracellular bacteria that cause important diseases in a wide variety of animals worldwide, including humans and fish. Several genes that are important for intramacrophage survival have been identified, including the iglC gene, which is found in the iglABCD operon in the Francisella sp. pathogenicity island (FPI). In the present study, we examined the interaction of wild-type Francisella asiatica and a Delta iglC mutant strain with fish serum and head kidney-derived macrophages (HKDM). Both the wild-type and the mutant strains were resistant to killing by normal and heat-inactivated sera. The wild-type F. asiatica is able to invade tilapia head kidney-derived macrophages and replicate vigorously within them, causing apoptosis and cytotoxicity in the macrophages at 24 and 36 h postinfection. The Delta iglC mutant, however, is defective for survival, replication, and the ability to cause cytotoxicity in HKDM, but the ability is restored when the mutant is complemented with the iglC gene. Uptake by the HKDM was mediated partially by complement and partially by macrophage mannose receptors, as demonstrated by in vitro assays. Light and electron microscopy analysis of the infected macrophages revealed intracellular bacteria present in a tight vacuole at 2 h postinoculation and the presence of numerous bacteria in spacious vacuoles at 12 h postinfection, with some bacteria free in the cytoplasm.
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Phillips AJ, Anderson VL, Robertson EJ, Secombes CJ, van West P. New insights into animal pathogenic oomycetes. Trends Microbiol 2008; 16:13-9. [DOI: 10.1016/j.tim.2007.10.013] [Citation(s) in RCA: 150] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2007] [Revised: 10/15/2007] [Accepted: 10/15/2007] [Indexed: 11/15/2022]
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Bowden TJ, Thompson KD, Morgan AL, Gratacap RML, Nikoskelainen S. Seasonal variation and the immune response: a fish perspective. FISH & SHELLFISH IMMUNOLOGY 2007; 22:695-706. [PMID: 17116408 DOI: 10.1016/j.fsi.2006.08.016] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2006] [Revised: 08/17/2006] [Accepted: 08/25/2006] [Indexed: 05/12/2023]
Abstract
The environment in which an animal lives affects the physiology and psychology of that animal. The greater the distance from the equator the more profound this influence becomes, as the environment becomes more variable over the years. Temperature, photoperiod, precipitation and other environmental conditions, which are directly or indirectly controlled by the season, can affect an animal. It is becoming apparent that these conditions may impact on the immune system, and this can affect animal health. This review looks at the known mechanisms for transducing environmental cues and how these can affect immune parameters and function. The main focus is fish, especially in relation to aquaculture and the associated disease risks. Work on other animal classes is included for comparison.
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Affiliation(s)
- Tim J Bowden
- Department of Zoology, University of Aberdeen, Tillydrone Avenue, Aberdeen AB24 2TZ, Scotland, UK.
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Kales SC, DeWitte-Orr SJ, Bols NC, Dixon B. Response of the rainbow trout monocyte/macrophage cell line, RTS11 to the water molds Achlya and Saprolegnia. Mol Immunol 2007; 44:2303-14. [PMID: 17204328 DOI: 10.1016/j.molimm.2006.11.007] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2006] [Revised: 10/20/2006] [Accepted: 11/06/2006] [Indexed: 10/23/2022]
Abstract
The Saprolegniales are responsible for various fish mycoses worldwide and considered the most important fungi afflicting fresh water fish. Saprolegniosis leads to massive epidermal destruction and macrophage recruitment, yet little is known regarding the cytological response of their piscine hosts. The objective of this study was to explore the response of fish macrophage to members of the Saprolegniales using the rainbow trout monocyte/macrophage cell line, RTS11. After 48 h in co-culture, RTS11 demonstrated chemotaxis, adherence and homotypic aggregation to both live and heat-killed fungal spores and mycelia. This aggregation was enhanced when using conditioned media from co-cultured RTS11 and Achlya, suggesting the presence of synergistic effectors of aggregation. Although fungal toxins were not evident, as cells remained viable throughout fungal overgrowth, phagocytosis was inhibited due to large fungal spore size, allowing these molds to evade macrophage defenses. Although class I MH and other viral response genes showed no significant change in expression, calreticulin and interleukin-8 were moderately up-regulated implicating calcium modulation and chemotactic response, respectively. Cyclooxygenase (COX-2) and the cytokines IL-1beta and TNFalpha were strongly up-regulated in the presence of Achlya, while gene expression of the class II major histocompatibility (MH II) receptor and associated molecules appeared down-regulated, suggesting fungal interference of immune function. Previous studies have shown an increased dependence of macrophage in immune function at low temperatures; based upon data presented here, this reduction of macrophage MH II receptor expression and inability to phagocytose spores may limit host response thereby providing increased susceptibility to these opportunistic pathogens.
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Affiliation(s)
- Stephen C Kales
- Department of Biology, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, Canada N2L 3G1
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Boshra H, Li J, Sunyer JO. Recent advances on the complement system of teleost fish. FISH & SHELLFISH IMMUNOLOGY 2006; 20:239-62. [PMID: 15950490 DOI: 10.1016/j.fsi.2005.04.004] [Citation(s) in RCA: 388] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2005] [Accepted: 04/04/2005] [Indexed: 05/02/2023]
Abstract
The complement system plays an essential role in alerting the host of the presence of potential pathogens, as well as in their clearing. In addition, activation of the complement system contributes significantly in the orchestration and development of an acquired immune response. Although the complement system has been studied extensively in mammals, considerably less is known about complement in lower vertebrates, in particular teleost fish. Here we review our current understanding of the role of fish complement in phagocytosis, respiratory burst, chemotaxis and cell lysis. We also thoroughly review the specific complement components characterized thus far in various teleost fish species. In addition, we provide a comprehensive compilation on complement host-pathogen interactions, in which we analyze the role of fish complement in host defense against bacteria, viruses, fungi and parasites. From a more physiological perspective, we evaluate the knowledge accumulated on the influence of stress, nutrition and environmental factors on levels of complement activity and components, and how the use of this knowledge can benefit the aquaculture industry. Finally, we propose future directions that are likely to advance our understanding of the molecular evolution, structure and function of complement proteins in teleosts. Such studies will be pivotal in providing new insights into complement-related mechanisms of recognition and defense that are essential to maintaining fish homeostasis.
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Affiliation(s)
- H Boshra
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, 413 Rosenthal, 3800 Spruce St., Philadelphia, PA 19104, USA
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Nitzan S, Shwartsburd B, Heller ED. The effect of storing hybrid bass (Morone saxatilis x M. chrysops) sera at freezing temperatures on antibody titers. FISH & SHELLFISH IMMUNOLOGY 2003; 15:341-347. [PMID: 12969655 DOI: 10.1016/s1050-4648(02)00179-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The effect of storing hybrid bass sera at freezing temperatures on their enzyme-linked immunosorbent assay (ELISA) titers was determined, and the precipitate formed during storage was characterized. Frozen bass sera from fish vaccinated with bacterial sonicate showed no titer in either of two groups-one immunized with bacterial sonicate and the other with sonicate emulsified in adjuvant. Fresh sera exhibited average titers of 1:32 in both groups and 1:20 in convalescent serum. Hybrid bass antisera to bovine serum albumin showed maximum ELISA OD when sera were used after a short storage at 4 degrees C. Storage at freezing temperatures (-20 and -73 degrees C) reduced the OD value substantially. Sodium dodecyl sulphate polyacrylamide gel electrophoresis analysis of the cryoprecipitate formed after freezing hybrid bass sera showed protein bands at 85 and 38 kDa, most probably the heavy and light chains, respectively, of bass IgM. Bands at 55, 52, 28, and 26 kDa may represent fibrinogen subunits. It is possible that the cryoprecipitate is composed of a fibrinogen net, which traps the tetrameric IgM molecules and precipitates them during frozen storage.
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Affiliation(s)
- S Nitzan
- Central Fish Health Laboratory, Department of Fisheries and Agriculture and Rural Development, Nir-David 19150, Israel.
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Abstract
Fungal diseases of fish have become increasingly important over the past 20 years. The traditional "fungi" are comprised of members from several different taxonomic kingdoms. Saprolegnia and other typical water molds are the "classic" secondary invaders, infecting more superficial areas of the body and requiring compromise of the exterior of the fish, poor water quality, or general immunosuppression. An increasing number of other environmental fungi are being reported from diseased fish, further testament to the opportunistic nature of many fungi. Common procedures such as air bladder deflation for many marine species collected at depth under nonsterile conditions may result in fungal infections of the swim bladder. Some fungi such as Aphanomyces and Fusarium can cause more invasive or systemic disease, often associated with changes in environmental factors such as temperature and salinity. Other fungi such as I. hoferi can be even more insidious and chronic, mimicking mycobacteriosis to a degree. Fungal diseases, in general, are very difficult to control or treat once they have taken hold. Prevention is, as always, the best medicine. Increased knowledge of basic biology will help guide treatment and control methods. Further research on general predisposing factors, species susceptibilities, immune system effects and other protective mechanisms in fish and more effective chemotherapeutics for external and systemic infections are needed.
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Affiliation(s)
- Roy P E Yanong
- Tropical Aquaculture Laboratory, Department of Fisheries and Aquatic Sciences, Institute of Food and Agricultural Sciences, University of Florida, Ruskin, FL 33570, USA.
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