In vitro investigations on extracellular proteins secreted by Aphanomyces invadans, the causative agent of epizootic ulcerative syndrome

Abstract Background Proteases produced by many microorganisms, including oomycetes, are crucial for their growth and development. They may also play a critical role in disease manifestation. Epizootic ulcerative syndrome is one of the most destructive fish diseases known. It is caused by the oomycet...

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Main Authors: Muhammad Majeed, Gokhlesh Kumar, Sarah Schlosser, Mansour El-Matbouli, Mona Saleh
Format: Article
Language:English
Published: BMC 2017-11-01
Series:Acta Veterinaria Scandinavica
Subjects:
Online Access:http://link.springer.com/article/10.1186/s13028-017-0347-3
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author Muhammad Majeed
Gokhlesh Kumar
Sarah Schlosser
Mansour El-Matbouli
Mona Saleh
author_facet Muhammad Majeed
Gokhlesh Kumar
Sarah Schlosser
Mansour El-Matbouli
Mona Saleh
author_sort Muhammad Majeed
collection DOAJ
description Abstract Background Proteases produced by many microorganisms, including oomycetes, are crucial for their growth and development. They may also play a critical role in disease manifestation. Epizootic ulcerative syndrome is one of the most destructive fish diseases known. It is caused by the oomycete Aphanomyces invadans and leads to mass mortalities of cultured and wild fish in many countries. The areas of concern are Australia, China, Japan, South and Southeast Asian countries and the USA. Extracellular proteases produced by this oomycete are believed to trigger EUS pathogenesis in fish. To address this activity, we collected the extracellular products (ECP) of A. invadans and identified the secreted proteins using SDS-PAGE and mass spectrometery. A. invadans was cultivated in liquid Glucose-Peptone-Yeats media. The culture media was ultra-filtered through 10 kDa filters and analysed using SDS-PAGE. Three prominent protein bands from the SDS gel were excised and identified by mass spectrometery. Furthermore, we assessed their proteolytic effect on casein and immunoglobulin M (IgM) of rainbow trout (Oncorhynchus mykiss) and giant gourami (Osphronemus goramy). Antiprotease activity of the fish serum was also investigated. Results BLASTp analysis revealed that the prominent secreted proteins were proteases, mainly of the serine and cysteine types. Proteins containing fascin-like domain and bromodomain were also identified. We could demonstrate that the secreted proteases showed proteolytic activity against the casein and the IgM of both fish species. The anti-protease activity experiment showed that the percent inhibition of the common carp serum was 94.2% while that of rainbow trout and giant gourami serum was 7.7 and 12.9%, respectively. Conclusions The identified proteases, especially serine proteases, could be the potential virulence factors in A. invadans and, hence, are candidates for further functional and host–pathogen interaction studies. The role of identified structural proteins in A. invadans also needs to be investigated further.
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spelling doaj.art-b08ac575816a4dd28e7c6371b37a629b2022-12-22T02:38:53ZengBMCActa Veterinaria Scandinavica1751-01472017-11-015911910.1186/s13028-017-0347-3In vitro investigations on extracellular proteins secreted by Aphanomyces invadans, the causative agent of epizootic ulcerative syndromeMuhammad Majeed0Gokhlesh Kumar1Sarah Schlosser2Mansour El-Matbouli3Mona Saleh4Clinical Division of Fish Medicine, University of Veterinary MedicineClinical Division of Fish Medicine, University of Veterinary MedicineVetCore Facility for Research, University of Veterinary MedicineClinical Division of Fish Medicine, University of Veterinary MedicineClinical Division of Fish Medicine, University of Veterinary MedicineAbstract Background Proteases produced by many microorganisms, including oomycetes, are crucial for their growth and development. They may also play a critical role in disease manifestation. Epizootic ulcerative syndrome is one of the most destructive fish diseases known. It is caused by the oomycete Aphanomyces invadans and leads to mass mortalities of cultured and wild fish in many countries. The areas of concern are Australia, China, Japan, South and Southeast Asian countries and the USA. Extracellular proteases produced by this oomycete are believed to trigger EUS pathogenesis in fish. To address this activity, we collected the extracellular products (ECP) of A. invadans and identified the secreted proteins using SDS-PAGE and mass spectrometery. A. invadans was cultivated in liquid Glucose-Peptone-Yeats media. The culture media was ultra-filtered through 10 kDa filters and analysed using SDS-PAGE. Three prominent protein bands from the SDS gel were excised and identified by mass spectrometery. Furthermore, we assessed their proteolytic effect on casein and immunoglobulin M (IgM) of rainbow trout (Oncorhynchus mykiss) and giant gourami (Osphronemus goramy). Antiprotease activity of the fish serum was also investigated. Results BLASTp analysis revealed that the prominent secreted proteins were proteases, mainly of the serine and cysteine types. Proteins containing fascin-like domain and bromodomain were also identified. We could demonstrate that the secreted proteases showed proteolytic activity against the casein and the IgM of both fish species. The anti-protease activity experiment showed that the percent inhibition of the common carp serum was 94.2% while that of rainbow trout and giant gourami serum was 7.7 and 12.9%, respectively. Conclusions The identified proteases, especially serine proteases, could be the potential virulence factors in A. invadans and, hence, are candidates for further functional and host–pathogen interaction studies. The role of identified structural proteins in A. invadans also needs to be investigated further.http://link.springer.com/article/10.1186/s13028-017-0347-3Aphanomyces invadansEpizootic ulcerative syndromeLC–MS/MSOomycetesProteasesVirulence
spellingShingle Muhammad Majeed
Gokhlesh Kumar
Sarah Schlosser
Mansour El-Matbouli
Mona Saleh
In vitro investigations on extracellular proteins secreted by Aphanomyces invadans, the causative agent of epizootic ulcerative syndrome
Acta Veterinaria Scandinavica
Aphanomyces invadans
Epizootic ulcerative syndrome
LC–MS/MS
Oomycetes
Proteases
Virulence
title In vitro investigations on extracellular proteins secreted by Aphanomyces invadans, the causative agent of epizootic ulcerative syndrome
title_full In vitro investigations on extracellular proteins secreted by Aphanomyces invadans, the causative agent of epizootic ulcerative syndrome
title_fullStr In vitro investigations on extracellular proteins secreted by Aphanomyces invadans, the causative agent of epizootic ulcerative syndrome
title_full_unstemmed In vitro investigations on extracellular proteins secreted by Aphanomyces invadans, the causative agent of epizootic ulcerative syndrome
title_short In vitro investigations on extracellular proteins secreted by Aphanomyces invadans, the causative agent of epizootic ulcerative syndrome
title_sort in vitro investigations on extracellular proteins secreted by aphanomyces invadans the causative agent of epizootic ulcerative syndrome
topic Aphanomyces invadans
Epizootic ulcerative syndrome
LC–MS/MS
Oomycetes
Proteases
Virulence
url http://link.springer.com/article/10.1186/s13028-017-0347-3
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