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Santibáñez N, Vega M, Pérez T, Enriquez R, Escalona CE, Oliver C, Romero A. In vitro effects of phytogenic feed additive on Piscirickettsia salmonis growth and biofilm formation. JOURNAL OF FISH DISEASES 2024; 47:e13913. [PMID: 38421380 DOI: 10.1111/jfd.13913] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 12/15/2023] [Accepted: 12/20/2023] [Indexed: 03/02/2024]
Abstract
Piscirickettsiosis is the main cause of mortality in salmonids of commercial importance in Chile, which is caused by Piscirickettsia salmonis, a Gram-negative, γ-proteobacteria that can produce biofilm as one of its virulence factors. The Chilean salmon industry uses large amounts of antibiotics to control piscirickettsiosis outbreaks, which has raised concern about its environmental impact and the potential to induce antibiotic resistance. Thus, the use of phytogenic feed additives (PFA) with antibacterial activity emerges as an interesting alternative to antimicrobials. Our study describes the antimicrobial action of an Andrographis paniculate-extracted PFA on P. salmonis planktonic growth and biofilm formation. We observed complete inhibition of planktonic and biofilm growth with 500 and 400 μg/mL of PFA for P. salmonis LF-89 and EM-90-like strains, respectively. Furthermore, 500 μg/mL of PFA was bactericidal for both evaluated bacterial strains. Sub-inhibitory doses of PFA increase the transcript levels of stress (groEL), biofilm (pslD), and efflux pump (acrB) genes for both P. salmonis strains in planktonic and sessile conditions. In conclusion, our results demonstrate the antibacterial effect of PFA against P. salmonis in vitro, highlighting the potential of PFA as an alternative to control Piscirickettsiosis.
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Affiliation(s)
- Natacha Santibáñez
- Laboratorio de Inmunología y Estrés de Organismos Acuáticos, Instituto de Patología Animal, Facultad de Ciencias Veterinarias, Universidad Austral de Chile, Valdivia, Chile
- Interdisciplinary Center for Aquaculture Research (INCAR), Centro FONDAP, Concepción, Chile
| | - Matías Vega
- Laboratorio de Inmunología y Estrés de Organismos Acuáticos, Instituto de Patología Animal, Facultad de Ciencias Veterinarias, Universidad Austral de Chile, Valdivia, Chile
- Interdisciplinary Center for Aquaculture Research (INCAR), Centro FONDAP, Concepción, Chile
| | - Tatiana Pérez
- Laboratorio de Inmunología y Estrés de Organismos Acuáticos, Instituto de Patología Animal, Facultad de Ciencias Veterinarias, Universidad Austral de Chile, Valdivia, Chile
- Interdisciplinary Center for Aquaculture Research (INCAR), Centro FONDAP, Concepción, Chile
| | - Ricardo Enriquez
- Laboratorio de Inmunología y Estrés de Organismos Acuáticos, Instituto de Patología Animal, Facultad de Ciencias Veterinarias, Universidad Austral de Chile, Valdivia, Chile
| | - Carla Estefanía Escalona
- Laboratorio de Inmunología y Estrés de Organismos Acuáticos, Instituto de Patología Animal, Facultad de Ciencias Veterinarias, Universidad Austral de Chile, Valdivia, Chile
- Interdisciplinary Center for Aquaculture Research (INCAR), Centro FONDAP, Concepción, Chile
| | - Cristian Oliver
- Laboratorio de Inmunología y Estrés de Organismos Acuáticos, Instituto de Patología Animal, Facultad de Ciencias Veterinarias, Universidad Austral de Chile, Valdivia, Chile
| | - Alex Romero
- Laboratorio de Inmunología y Estrés de Organismos Acuáticos, Instituto de Patología Animal, Facultad de Ciencias Veterinarias, Universidad Austral de Chile, Valdivia, Chile
- Interdisciplinary Center for Aquaculture Research (INCAR), Centro FONDAP, Concepción, Chile
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2
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Isla A, Sánchez P, Ruiz P, Albornoz R, Pontigo JP, Rauch MC, Hawes C, Vargas-Chacoff L, Yáñez AJ. Effect of low-dose Piscirickettsia salmonis infection on haematological-biochemical blood parameters in Atlantic salmon (Salmo salar). JOURNAL OF FISH BIOLOGY 2022; 101:1021-1032. [PMID: 35838309 DOI: 10.1111/jfb.15167] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Accepted: 07/13/2022] [Indexed: 06/15/2023]
Abstract
Piscirickettsia salmonis is the etiological agent of Piscirickettsiosis, a severe disease that affects Atlantic salmon (Salmo salar) farmed in Chile and many other areas (Norway, Scotland, Ireland, Canada and the USA). This study investigated the effects of low-dose P. salmonis infection (1 × 102 CFU/ml) on Atlantic salmon. In this study, we challenged fish with an isolated representative of the EM-90 genogroup via intraperitoneal injection for 42 days. Infected fish displayed decreased haematocrit and haemoglobin levels at day 13 post-infection, indicating erythropenia, haemolysis and haemodilution. Conversely, their white blood cell counts increased on days 13 and 21 post-infection. Additionally, their iron levels decreased from day 2 post-infection, indicating iron deficiency and an inability to retrieve stored iron before infection. Their magnesium levels also decreased at day 28 post-infection, possibly due to osmoregulatory problems. Also, we observed an increase in lactate dehydrogenase activity on days 5, 21, and 28 post-infection, suggesting early symptoms of hepatotoxicity. Later analyses determined a decrease in plasma glucose levels from day 2 post-infection. This may be attributed to the hypoxic conditions caused by P. salmonis, leading to an excess utilization of stored carbohydrates. Our results suggest that the blood parameters we studied are useful for monitoring the physiological status of Atlantic salmon infected with P. salmonis.
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Affiliation(s)
- Adolfo Isla
- Instituto de Bioquímica y Microbiología, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile
- Departamento de Ciencias Básicas, Facultad de Ciencias, Universidad Santo Tomás, Valdivia, Chile
- Interdisciplinary Center for Aquaculture Research, Concepción, Chile
| | - Patricio Sánchez
- Instituto de Bioquímica y Microbiología, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile
| | - Pamela Ruiz
- Instituto de Bioquímica y Microbiología, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile
- Interdisciplinary Center for Aquaculture Research, Concepción, Chile
| | - Romina Albornoz
- Interdisciplinary Center for Aquaculture Research, Concepción, Chile
| | - Juan P Pontigo
- Laboratorio de Biotecnología Aplicada, Facultad de Ciencas de la Naturaleza, Escuela de Medicina Veterinaria, Universidad San Sebastián, Puerto Montt, Chile
| | - María Cecilia Rauch
- Instituto de Bioquímica y Microbiología, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile
| | | | - Luis Vargas-Chacoff
- Centro Fondap de Investigación de Altas Latitudes, Universidad Austral de Chile, Valdivia, Chile
| | - Alejandro J Yáñez
- Interdisciplinary Center for Aquaculture Research, Concepción, Chile
- Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile
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3
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Fuentes DE, Acuña LG, Calderón IL. Stress response and virulence factors in bacterial pathogens relevant for Chilean aquaculture: current status and outlook of our knowledge. Biol Res 2022; 55:21. [PMID: 35642071 PMCID: PMC9153119 DOI: 10.1186/s40659-022-00391-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Accepted: 05/17/2022] [Indexed: 11/10/2022] Open
Abstract
The study of the stress responses in bacteria has given us a wealth of information regarding the mechanisms employed by these bacteria in aggressive or even non-optimal living conditions. This information has been applied by several researchers to identify molecular targets related to pathogeny, virulence, and survival, among others, and to design new prophylactic or therapeutic strategies against them. In this study, our knowledge of these mechanisms has been summarized with emphasis on some aquatic pathogenic bacteria of relevance to the health and productive aspects of Chilean salmon farming (Piscirickettsia salmonis, Tenacibaculum spp., Renibacterium salmoninarum, and Yersinia ruckeri). This study will aid further investigations aimed at shedding more light on possible lines of action for these pathogens in the coming years.
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Affiliation(s)
- Derie E Fuentes
- Aquaculture and Marine Ecosystems, Center For Systems Biotechnology, Fraunhofer Chile Research, Santiago, Chile. .,Environmental Sustainability, Center for Systems Biotechnology (CSB-UNAB), Universidad Andres Bello, Facultad de Ciencias de la Vida, Santiago, Chile.
| | - Lillian G Acuña
- Laboratorio de RNAs Bacterianos, Departamento de Ciencias Biológicas, Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago, Chile.,Interdisciplinary Center for Aquaculture Research, Universidad Andres Bello, Viña del Mar, Santiago, Chile
| | - Iván L Calderón
- Laboratorio de RNAs Bacterianos, Departamento de Ciencias Biológicas, Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago, Chile
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4
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Rozas-Serri M. Why Does Piscirickettsia salmonis Break the Immunological Paradigm in Farmed Salmon? Biological Context to Understand the Relative Control of Piscirickettsiosis. Front Immunol 2022; 13:856896. [PMID: 35386699 PMCID: PMC8979166 DOI: 10.3389/fimmu.2022.856896] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Accepted: 02/22/2022] [Indexed: 11/28/2022] Open
Abstract
Piscirickettsiosis (SRS) has been the most important infectious disease in Chilean salmon farming since the 1980s. It was one of the first to be described, and to date, it continues to be the main infectious cause of mortality. How can we better understand the epidemiological situation of SRS? The catch-all answer is that the Chilean salmon farming industry must fight year after year against a multifactorial disease, and apparently only the environment in Chile seems to favor the presence and persistence of Piscirickettsia salmonis. This is a fastidious, facultative intracellular bacterium that replicates in the host’s own immune cells and antigen-presenting cells and evades the adaptive cell-mediated immune response, which is why the existing vaccines are not effective in controlling it. Therefore, the Chilean salmon farming industry uses a lot of antibiotics—to control SRS—because otherwise, fish health and welfare would be significantly impaired, and a significantly higher volume of biomass would be lost per year. How can the ever-present risk of negative consequences of antibiotic use in salmon farming be balanced with the productive and economic viability of an animal production industry, as well as with the care of the aquatic environment and public health and with the sustainability of the industry? The answer that is easy, but no less true, is that we must know the enemy and how it interacts with its host. Much knowledge has been generated using this line of inquiry, however it remains insufficient. Considering the state-of-the-art summarized in this review, it can be stated that, from the point of view of fish immunology and vaccinology, we are quite far from reaching an effective and long-term solution for the control of SRS. For this reason, the aim of this critical review is to comprehensively discuss the current knowledge on the interaction between the bacteria and the host to promote the generation of more and better measures for the prevention and control of SRS.
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5
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Zuloaga R, Dettleff P, Bastias-Molina M, Meneses C, Altamirano C, Valdés JA, Molina A. RNA-Seq-Based Analysis of Cortisol-Induced Differential Gene Expression Associated with Piscirickettsia salmonis Infection in Rainbow Trout ( Oncorhynchus mykiss) Myotubes. Animals (Basel) 2021; 11:ani11082399. [PMID: 34438856 PMCID: PMC8388646 DOI: 10.3390/ani11082399] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 08/09/2021] [Accepted: 08/11/2021] [Indexed: 12/22/2022] Open
Abstract
Salmonid rickettsial septicemia (SRS) is the major infectious disease of the Chilean salmonid aquaculture industry caused by Piscirickettsia salmonis. Intensive farming conditions generate stress and increased susceptibility to diseases, being skeletal muscle mainly affected. However, the interplay between pathogen infection and stress in muscle is poorly understood. In this study, we perform an RNA-seq analysis on rainbow trout myotubes that are pretreated for 3 h with cortisol (100 ng/mL) and then infected with P. salmonis strain LF-89 for 8 h (MOI 50). Twelve libraries are constructed from RNA samples (n = 3 per group) and sequenced on Illumina HiSeq 4000. A total of 704,979,454 high-quality reads are obtained, with 70.25% mapped against the reference genome. In silico DETs include 175 total genes-124 are upregulated and 51 are downregulated. GO enrichment analysis reveals highly impacted biological processes related to apoptosis, negative regulation of cell proliferation, and innate immune response. These results are validated by RT-qPCR of nine candidate transcripts. Furthermore, cortisol pretreatment significantly stimulated bacterial gene expression of ahpC and 23s compared to infection. In conclusion, for the first time, we describe a transcriptomic response of trout myotubes infected with P. salmonis by inducing apoptosis, downregulating cell proliferation, and intrinsic immune-like response that is differentially regulated by cortisol.
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Affiliation(s)
- Rodrigo Zuloaga
- Laboratorio de Biotecnología Molecular, Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago 8370186, Chile; (R.Z.); (P.D.); (J.A.V.)
- Interdisciplinary Center for Aquaculture Research (INCAR), Concepción 4030000, Chile
| | - Phillip Dettleff
- Laboratorio de Biotecnología Molecular, Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago 8370186, Chile; (R.Z.); (P.D.); (J.A.V.)
| | - Macarena Bastias-Molina
- Centro de Biotecnología Vegetal, Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago 8370186, Chile; (M.B.-M.); (C.M.)
| | - Claudio Meneses
- Centro de Biotecnología Vegetal, Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago 8370186, Chile; (M.B.-M.); (C.M.)
| | - Claudia Altamirano
- Laboratorio de Cultivos Celulares, Escuela de Ingeniería Bioquímica, Pontificia Universidad Católica de Valparaíso, Valparaíso 2362803, Chile;
| | - Juan Antonio Valdés
- Laboratorio de Biotecnología Molecular, Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago 8370186, Chile; (R.Z.); (P.D.); (J.A.V.)
- Interdisciplinary Center for Aquaculture Research (INCAR), Concepción 4030000, Chile
- Centro de Investigación Marina Quintay (CIMARQ), Facultad de Ciencias de la Vida, Universidad Andres Bello, Valparaíso 2340000, Chile
| | - Alfredo Molina
- Laboratorio de Biotecnología Molecular, Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago 8370186, Chile; (R.Z.); (P.D.); (J.A.V.)
- Interdisciplinary Center for Aquaculture Research (INCAR), Concepción 4030000, Chile
- Centro de Investigación Marina Quintay (CIMARQ), Facultad de Ciencias de la Vida, Universidad Andres Bello, Valparaíso 2340000, Chile
- Correspondence: ; Tel.: +56-227703067
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6
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Zúñiga A, Solis C, Cartes C, Nourdin G, Yañez A, Romero A, Haussmann D, Figueroa J. Transcriptional analysis of metabolic and virulence genes associated with biofilm formation in Piscirickettsia salmonis strains. FEMS Microbiol Lett 2021; 367:5948097. [PMID: 33128546 DOI: 10.1093/femsle/fnaa180] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Accepted: 10/29/2020] [Indexed: 12/14/2022] Open
Abstract
Piscirickettsia salmonis is a facultative intracellular bacterium that generates piscirickettsiosis affecting salmonids in Chile. The bacterium has the adaptability to survive in the marine environment under multiple stressful conditions. In this sense, this work focused on the analysis of a gene battery associated with biofilm formation under different culture conditions and on the adaptability of this biofilm to different media. The results indicated that the strains LF-89, IBM-034 and IBM-040 were strong biofilm producers, evidencing adaptability to the media by increasing the amount of biofilm through successive growths. Transcript levels of six genes described in various bacteria and P. salmonis, considered to have metabolic functions, and playing a relevant role in biofilm formation, were analyzed to evaluate bacterial functionality in the biofilm. The genes mazE-mazF, implicated in biofilm and stress, were markedly overexpressed in the biofilm condition in the three strains. For its part, gene gltA, an indicator of metabolic activity and related to virulence inhibition in Salmonella typhimurium, also seems to restrain the pathogenesis process in P. salmonis by inhibiting the expression of the virulence-associated genes liso and tcf. Finally, the expression of the glnA gene suggests the use of glutamine as an essential element for the growth of the biofilm.
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Affiliation(s)
- A Zúñiga
- Institute of Biochemistry and Microbiology, Faculty of Sciences, Universidad Austral de Chile, Valdivia, Chile
| | - C Solis
- Institute of Biochemistry and Microbiology, Faculty of Sciences, Universidad Austral de Chile, Valdivia, Chile
| | - C Cartes
- Institute of Biochemistry and Microbiology, Faculty of Sciences, Universidad Austral de Chile, Valdivia, Chile.,FONDAP Centre: Interdisciplinary Centre for Aquaculture Research (INCAR), O'Higgins 1695, Concepción, Chile
| | - G Nourdin
- FONDAP Centre: Interdisciplinary Centre for Aquaculture Research (INCAR), O'Higgins 1695, Concepción, Chile
| | - A Yañez
- Institute of Biochemistry and Microbiology, Faculty of Sciences, Universidad Austral de Chile, Valdivia, Chile.,FONDAP Centre: Interdisciplinary Centre for Aquaculture Research (INCAR), O'Higgins 1695, Concepción, Chile
| | - A Romero
- FONDAP Centre: Interdisciplinary Centre for Aquaculture Research (INCAR), O'Higgins 1695, Concepción, Chile.,Institute of Animal Pathology, Faculty of Veterinary Sciences, Universidad Austral de Chile. Valdivia, Chile
| | - D Haussmann
- Department of Basic Sciences, Faculty of Sciences, Universidad Santo Tomás, Valdivia, Chile
| | - J Figueroa
- Institute of Biochemistry and Microbiology, Faculty of Sciences, Universidad Austral de Chile, Valdivia, Chile.,FONDAP Centre: Interdisciplinary Centre for Aquaculture Research (INCAR), O'Higgins 1695, Concepción, Chile
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7
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Carrizo V, Valenzuela CA, Aros C, Dettleff P, Valenzuela-Muñoz V, Gallardo-Escarate C, Altamirano C, Molina A, Valdés JA. Transcriptomic analysis reveals a Piscirickettsia salmonis-induced early inflammatory response in rainbow trout skeletal muscle. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY D-GENOMICS & PROTEOMICS 2021; 39:100859. [PMID: 34087760 DOI: 10.1016/j.cbd.2021.100859] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 04/15/2021] [Accepted: 05/23/2021] [Indexed: 12/18/2022]
Abstract
Skeletal muscle is the most abundant tissue in teleosts and is essential for movement and metabolism. Recently, it has been described that skeletal muscle can express and secrete immune-related molecules during pathogen infection. However, the role of this tissue during infection is poorly understood. To determine the immunocompetence of fish skeletal muscle, juvenile rainbow trout (Oncorhynchus mykiss) were challenged with Piscirickettsia salmonis strain LF-89. P. salmonis is the etiological agent of piscirickettsiosis, a severe disease that has caused major economic losses in the aquaculture industry. This gram-negative bacterium produces a chronic systemic infection that involves several organs and tissues in salmonids. Using high-throughput RNA-seq, we found that 60 transcripts were upregulated in skeletal muscle, mostly associated with inflammatory response and positive regulation of interleukin-8 production. Conversely, 141 transcripts were downregulated in association with muscle filament sliding and actin filament-based movement. To validate these results, we performed in vitro experiments using rainbow trout myotubes. In myotubes coincubated with P. salmonis strain LF-89 at an MOI of 50, we found increased expression of the proinflammatory cytokine il1b and the pattern recognition receptor tlr5s 8 and 12 h after infection. These results demonstrated that fish skeletal muscle is an immunologically active organ that can implement an early immunological response against P. salmonis.
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Affiliation(s)
- Victoria Carrizo
- Laboratorio de Biotecnología Molecular, Facultad de Ciencias de la Vida, Universidad Andres Bello, 8370186 Santiago, Chile; Interdisciplinary Center for Aquaculture Research (INCAR), 4030000 Concepción, Chile
| | - Cristián A Valenzuela
- Grupo de Marcadores Inmunológicos, Laboratorio de Genética e Inmunología Molecular, Instituto de Biología, Pontificia Universidad Católica de Valparaíso, 2340000 Valparaíso, Chile
| | - Camila Aros
- Laboratorio de Biotecnología Molecular, Facultad de Ciencias de la Vida, Universidad Andres Bello, 8370186 Santiago, Chile; Interdisciplinary Center for Aquaculture Research (INCAR), 4030000 Concepción, Chile; Laboratorio de Cultivos Celulares, Escuela de Ingeniería Bioquímica, Pontificia Universidad Católica de Valparaíso, 2340000 Valparaíso, Chile
| | - Phillip Dettleff
- Laboratorio de Biotecnología Molecular, Facultad de Ciencias de la Vida, Universidad Andres Bello, 8370186 Santiago, Chile; Interdisciplinary Center for Aquaculture Research (INCAR), 4030000 Concepción, Chile
| | - Valentina Valenzuela-Muñoz
- Laboratorio de Biotecnología Molecular, Facultad de Ciencias de la Vida, Universidad Andres Bello, 8370186 Santiago, Chile; Interdisciplinary Center for Aquaculture Research (INCAR), 4030000 Concepción, Chile; Laboratory of Biotechnology and Aquatic Genomics, Barrio Universitario s/n, Universidad de Concepción, Concepción, Chile
| | - Cristian Gallardo-Escarate
- Interdisciplinary Center for Aquaculture Research (INCAR), 4030000 Concepción, Chile; Laboratory of Biotechnology and Aquatic Genomics, Barrio Universitario s/n, Universidad de Concepción, Concepción, Chile
| | - Claudia Altamirano
- Laboratorio de Cultivos Celulares, Escuela de Ingeniería Bioquímica, Pontificia Universidad Católica de Valparaíso, 2340000 Valparaíso, Chile
| | - Alfredo Molina
- Laboratorio de Biotecnología Molecular, Facultad de Ciencias de la Vida, Universidad Andres Bello, 8370186 Santiago, Chile; Interdisciplinary Center for Aquaculture Research (INCAR), 4030000 Concepción, Chile; Universidad Andres Bello, Centro de Investigación Marina Quintay (CIMARQ), Facultad de Ciencias de la Vida, 2340000 Valparaíso, Chile
| | - Juan Antonio Valdés
- Laboratorio de Biotecnología Molecular, Facultad de Ciencias de la Vida, Universidad Andres Bello, 8370186 Santiago, Chile; Interdisciplinary Center for Aquaculture Research (INCAR), 4030000 Concepción, Chile; Universidad Andres Bello, Centro de Investigación Marina Quintay (CIMARQ), Facultad de Ciencias de la Vida, 2340000 Valparaíso, Chile.
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8
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Figueroa J, Villagrán D, Cartes C, Solis C, Nourdin-Galindo G, Haussmann D. Analysis of genes encoding for proteolytic enzymes and cytotoxic proteins as virulence factors of Piscirickettsia salmonis in SHK-1 cells. JOURNAL OF FISH DISEASES 2021; 44:495-504. [PMID: 33455005 DOI: 10.1111/jfd.13333] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 12/24/2020] [Accepted: 12/26/2020] [Indexed: 06/12/2023]
Abstract
Piscirickettsia salmonis is the causative agent of Piscirickettsiosis, a systemic disease generating high mortality rates in farmed salmon cultures of southern Chile. Proteolytic enzymes are important virulence factors since they play a key role in bacterial invasion and proliferation within the host. Bacteria growing in muscle tissues are known to secrete proteases, but no proteolytic enzymes have been described in P. salmonis to date. A battery of putative protease genes was found in the genomes and available strains of P. salmonis by bioinformatics analyses, and their identity was established through comparison with protease genes in databases. The transcript levels of five candidate genes were analysed by in vitro infection and qPCR. All strains were found to generate protease activity to varying degrees, and this was significantly increased when bacteria infected a salmon cell line. Gene expression of several types of proteases was also evidenced, with the highest levels corresponding to the type 1 secretion system (T1SS), which is also involved in the transport of haemolysin A, although transcripts with significant levels of peptidase M4 (thermolysin) and CLP protease were also found.
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Affiliation(s)
- Jaime Figueroa
- Instituto de Bioquímica y Microbiología, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile
- Centro FONDAP: Interdisciplinary Center for Aquaculture Research (INCAR), Concepción, Chile
| | - Daniela Villagrán
- Instituto de Bioquímica y Microbiología, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile
- Centro FONDAP: Interdisciplinary Center for Aquaculture Research (INCAR), Concepción, Chile
| | - Carlos Cartes
- Centro FONDAP: Interdisciplinary Center for Aquaculture Research (INCAR), Concepción, Chile
| | - Camila Solis
- Instituto de Bioquímica y Microbiología, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile
| | | | - Denise Haussmann
- Departmento de Ciencias Básicas, Facultad de Ciencias, Universidad Santo Tomás, Valdivia, Chile
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9
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Carrizo V, Valenzuela CA, Zuloaga R, Aros C, Altamirano C, Valdés JA, Molina A. Effect of cortisol on the immune-like response of rainbow trout (Oncorhynchus mykiss) myotubes challenged with Piscirickettsia salmonis. Vet Immunol Immunopathol 2021; 237:110240. [PMID: 33962313 DOI: 10.1016/j.vetimm.2021.110240] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 03/31/2021] [Accepted: 04/02/2021] [Indexed: 12/28/2022]
Abstract
Salmonids are a species of high commercial value in Chilean aquaculture, where muscle is the final product of the industry. Fish can be affected by stress during intensive cultures, increasing susceptibility to infections. Recently, we reported that muscle is an important focus of immune reactions. However, studies have shown the immunosuppressive effect of stress only in lymphoid organs, and few studies have been conducted on muscle and immunity. Hence, we determine the effects of cortisol on the immune-like response of fish myotubes challenged with Piscirickettsia salmonis by three trials. First, rainbow trout primary culture of muscle was cultured and treated with cortisol (100 ng/mL) for 3 and 4 h. Second, myotubes were challenged with P. salmonis (MOI 50) for 4, 6 and 8 h. And third, muscle cell cultures were pretreated with cortisol and then challenged with P. salmonis. The mRNA levels of glucocorticoid pathway and innate immunity were evaluated by qPCR. Cortisol increased the klf15 levels and downregulated the innate immune-related tlr5m gene and antimicrobial peptides. P. salmonis challenge upregulated several immune-related genes. Finally, cortisol pretreatment followed by P. salmonis challenge differentially modulated stress- and immune-related genes. These data suggest that fish muscle cells possess an intrinsic immune response and are differentially regulated by cortisol, which could lead to bacterial outbreaks in muscle under stress conditions.
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Affiliation(s)
- Victoria Carrizo
- Universidad Andres Bello, Laboratorio de Biotecnología Molecular, Facultad de Ciencias de la Vida, 8370146, Santiago, Chile; Interdisciplinary Center for Aquaculture Research (INCAR), 4030000, Concepción, Chile.
| | - Cristián A Valenzuela
- Grupo de Marcadores Inmunológicos, Laboratorio de Genética e Inmunología Molecular, Instituto de Biología, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile.
| | - Rodrigo Zuloaga
- Universidad Andres Bello, Laboratorio de Biotecnología Molecular, Facultad de Ciencias de la Vida, 8370146, Santiago, Chile; Interdisciplinary Center for Aquaculture Research (INCAR), 4030000, Concepción, Chile.
| | - Camila Aros
- Universidad Andres Bello, Laboratorio de Biotecnología Molecular, Facultad de Ciencias de la Vida, 8370146, Santiago, Chile; Interdisciplinary Center for Aquaculture Research (INCAR), 4030000, Concepción, Chile; Laboratorio de Cultivos Celulares, Escuela de Ingeniería Bioquímica, Pontificia Universidad Católica de Valparaíso, 2362803, Valparaíso, Chile.
| | - Claudia Altamirano
- Laboratorio de Cultivos Celulares, Escuela de Ingeniería Bioquímica, Pontificia Universidad Católica de Valparaíso, 2362803, Valparaíso, Chile.
| | - Juan A Valdés
- Universidad Andres Bello, Laboratorio de Biotecnología Molecular, Facultad de Ciencias de la Vida, 8370146, Santiago, Chile; Interdisciplinary Center for Aquaculture Research (INCAR), 4030000, Concepción, Chile; Universidad Andres Bello, Centro de Investigación Marina Quintay (CIMARQ), 2340000, Valparaíso, Chile.
| | - Alfredo Molina
- Universidad Andres Bello, Laboratorio de Biotecnología Molecular, Facultad de Ciencias de la Vida, 8370146, Santiago, Chile; Interdisciplinary Center for Aquaculture Research (INCAR), 4030000, Concepción, Chile; Universidad Andres Bello, Centro de Investigación Marina Quintay (CIMARQ), 2340000, Valparaíso, Chile.
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Abstract
Piscirickettsia salmonis, a fastidious Gram-negative intracellular facultative bacterium, is the causative agent o Piscirickettsiosis. P. salmonis has broad host range with a nearly worldwide distribution, causing significant mortality. The molecular regulatory mechanisms of P. salmonis pathogenesis are relatively unknown, mainly due to its difficult in vitro culture and genomic differences between genogroups. Bacterial non-coding RNAs (ncRNAs) are important post-transcriptional regulators of bacterial physiology and virulence that are predominantly transcribed from intergenic regions (trans-acting) or antisense strand of open reading frames (cis-acting). The repertoire of ncRNAs present in the genome of P. salmonis and its possible role in bacterial physiology and pathogenesis are unknown. Here, we predicted and analyzed the core ncRNAs of P. salmonis base on structure and correlate this prediction to RNA sequencing data. We identified a total of 69 ncRNA classes related to tRNAs, rRNA, thermoregulators, antitoxins, ribozymes, riboswitches, miRNAs and antisense-RNAs. Among these ncRNAs, 29 classes of ncRNAs are shared between all P. salmonis genomes, constituting the core ncRNAs of P. salmonis. The ncRNA core of P. salmonis could serve to develop diagnostic tools and explore the role of ncRNA in fish pathogenesis.
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