Defined Deletion Mutants Demonstrate that the Major Secreted Toxins Are Not Essential for the Virulence of Aeromonas salmonicida
The importance of the two major extracellular enzymes of Aeromonas salmonicida, glycerophospholipid:cholesterol acyltransferase (GCAT) and a serine protease (AspA), to the pathology and mortality of salmonid fish with furunculosis had been indicated in toxicity studies. In this study, the genes enco...
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ftpubmed:oai:pubmedcentral.nih.gov:108155 2023-05-15T15:31:47+02:00 Defined Deletion Mutants Demonstrate that the Major Secreted Toxins Are Not Essential for the Virulence of Aeromonas salmonicida Vipond, Richard Bricknell, Ian R. Durant, Emma Bowden, Timothy J. Ellis, Anthony E. Smith, Mary MacIntyre, Sheila 1998-05 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC108155 http://www.ncbi.nlm.nih.gov/pubmed/9573081 en eng American Society for Microbiology http://www.ncbi.nlm.nih.gov/pmc/articles/PMC108155 http://www.ncbi.nlm.nih.gov/pubmed/9573081 Copyright © 1998, American Society for Microbiology Molecular and Cellular Pathogenesis Text 1998 ftpubmed 2013-08-29T10:09:13Z The importance of the two major extracellular enzymes of Aeromonas salmonicida, glycerophospholipid:cholesterol acyltransferase (GCAT) and a serine protease (AspA), to the pathology and mortality of salmonid fish with furunculosis had been indicated in toxicity studies. In this study, the genes encoding GCAT (satA) and AspA (aspA) have been cloned and mutagenized by marker replacement of internal deletions, and the constructs have been used for the creation of isogenic satA and aspA mutants of A. salmonicida. A pSUP202 derivative (pSUP202sac) carrying the sacRB genes was constructed to facilitate the selection of mutants. The requirement of serine protease for processing of pro-GCAT was demonstrated. Processing involved the removal of a short internal fragment. Surprisingly, pathogenicity trials revealed no major decrease in virulence of the A. salmonicida ΔsatA::kan or A. salmonicida ΔaspA::kan mutants compared to the wild-type parent strains when Atlantic salmon (Salmo salar L.) were challenged by intraperitoneal injection. Moreover, using a cohabitation model, which more closely mimics the natural disease, there was also no significant decrease in the relative cumulative mortality following infection with either of the deletion mutants compared to the parent strain. Thus, although these two toxins may confer some competitive advantage to A. salmonicida, neither toxin is essential for the very high virulence of A. salmonicida in Atlantic salmon. This first report of defined deletion mutations within any proposed extracellular virulence factor of A. salmonicida raises crucial questions about the pathogenesis of this important fish pathogen. Text Atlantic salmon Salmo salar PubMed Central (PMC) |
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English |
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Molecular and Cellular Pathogenesis |
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Molecular and Cellular Pathogenesis Vipond, Richard Bricknell, Ian R. Durant, Emma Bowden, Timothy J. Ellis, Anthony E. Smith, Mary MacIntyre, Sheila Defined Deletion Mutants Demonstrate that the Major Secreted Toxins Are Not Essential for the Virulence of Aeromonas salmonicida |
topic_facet |
Molecular and Cellular Pathogenesis |
description |
The importance of the two major extracellular enzymes of Aeromonas salmonicida, glycerophospholipid:cholesterol acyltransferase (GCAT) and a serine protease (AspA), to the pathology and mortality of salmonid fish with furunculosis had been indicated in toxicity studies. In this study, the genes encoding GCAT (satA) and AspA (aspA) have been cloned and mutagenized by marker replacement of internal deletions, and the constructs have been used for the creation of isogenic satA and aspA mutants of A. salmonicida. A pSUP202 derivative (pSUP202sac) carrying the sacRB genes was constructed to facilitate the selection of mutants. The requirement of serine protease for processing of pro-GCAT was demonstrated. Processing involved the removal of a short internal fragment. Surprisingly, pathogenicity trials revealed no major decrease in virulence of the A. salmonicida ΔsatA::kan or A. salmonicida ΔaspA::kan mutants compared to the wild-type parent strains when Atlantic salmon (Salmo salar L.) were challenged by intraperitoneal injection. Moreover, using a cohabitation model, which more closely mimics the natural disease, there was also no significant decrease in the relative cumulative mortality following infection with either of the deletion mutants compared to the parent strain. Thus, although these two toxins may confer some competitive advantage to A. salmonicida, neither toxin is essential for the very high virulence of A. salmonicida in Atlantic salmon. This first report of defined deletion mutations within any proposed extracellular virulence factor of A. salmonicida raises crucial questions about the pathogenesis of this important fish pathogen. |
format |
Text |
author |
Vipond, Richard Bricknell, Ian R. Durant, Emma Bowden, Timothy J. Ellis, Anthony E. Smith, Mary MacIntyre, Sheila |
author_facet |
Vipond, Richard Bricknell, Ian R. Durant, Emma Bowden, Timothy J. Ellis, Anthony E. Smith, Mary MacIntyre, Sheila |
author_sort |
Vipond, Richard |
title |
Defined Deletion Mutants Demonstrate that the Major Secreted Toxins Are Not Essential for the Virulence of Aeromonas salmonicida |
title_short |
Defined Deletion Mutants Demonstrate that the Major Secreted Toxins Are Not Essential for the Virulence of Aeromonas salmonicida |
title_full |
Defined Deletion Mutants Demonstrate that the Major Secreted Toxins Are Not Essential for the Virulence of Aeromonas salmonicida |
title_fullStr |
Defined Deletion Mutants Demonstrate that the Major Secreted Toxins Are Not Essential for the Virulence of Aeromonas salmonicida |
title_full_unstemmed |
Defined Deletion Mutants Demonstrate that the Major Secreted Toxins Are Not Essential for the Virulence of Aeromonas salmonicida |
title_sort |
defined deletion mutants demonstrate that the major secreted toxins are not essential for the virulence of aeromonas salmonicida |
publisher |
American Society for Microbiology |
publishDate |
1998 |
url |
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC108155 http://www.ncbi.nlm.nih.gov/pubmed/9573081 |
genre |
Atlantic salmon Salmo salar |
genre_facet |
Atlantic salmon Salmo salar |
op_relation |
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC108155 http://www.ncbi.nlm.nih.gov/pubmed/9573081 |
op_rights |
Copyright © 1998, American Society for Microbiology |
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