{"title":"Regeneration of tunic cuticle is suppressed in edible ascidian Halocynthia roretzi contracting soft tunic syndrome.","authors":"Kei Nakayama, Yumiko Obayashi, Leo Munechika, Shin-Ichi Kitamura, Tetsuya Yanagida, Miho Honjo, Shoko Murakami, Euichi Hirose","doi":"10.3354/dao03801","DOIUrl":null,"url":null,"abstract":"<p><p>Soft tunic syndrome is an infectious disease caused by the flagellate Azumiobodo hoyamushi, which severely damages the aquaculture of the edible ascidian Halocynthia roretzi. Tunic is a cellulosic extracellular matrix entirely covering the body in ascidians and other tunicates, and its dense cuticle layer covers the tunic surface as a physical barrier against microorganisms. When the tunic of intact H. roretzi individuals was cut into strips, electron-dense fibers (DFs) appeared on the cut surface of the tunic matrix and aggregated to regenerate a new cuticular layer in seawater within a few days. DF formation was partially or completely inhibited in individuals with soft tunic syndrome, and DF formation was also inhibited by the presence of some proteases, indicating the involvement of proteolysis in the process of tunic softening as well as cuticle regeneration. Using pure cultures of the causative flagellate A. hoyamushi, the expression of protease genes and secretion of some proteases were confirmed by RNA-seq analysis and a 4-methylcoumaryl-7-amide substrate assay. Some of these proteases may degrade proteins in the tunic matrix. These findings suggest that the proteases of A. hoyamushi is the key to understanding the mechanisms of cuticular regeneration inhibition and tunic softening.</p>","PeriodicalId":11252,"journal":{"name":"Diseases of aquatic organisms","volume":null,"pages":null},"PeriodicalIF":1.1000,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Diseases of aquatic organisms","FirstCategoryId":"97","ListUrlMain":"https://doi.org/10.3354/dao03801","RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"FISHERIES","Score":null,"Total":0}
引用次数: 0
Abstract
Soft tunic syndrome is an infectious disease caused by the flagellate Azumiobodo hoyamushi, which severely damages the aquaculture of the edible ascidian Halocynthia roretzi. Tunic is a cellulosic extracellular matrix entirely covering the body in ascidians and other tunicates, and its dense cuticle layer covers the tunic surface as a physical barrier against microorganisms. When the tunic of intact H. roretzi individuals was cut into strips, electron-dense fibers (DFs) appeared on the cut surface of the tunic matrix and aggregated to regenerate a new cuticular layer in seawater within a few days. DF formation was partially or completely inhibited in individuals with soft tunic syndrome, and DF formation was also inhibited by the presence of some proteases, indicating the involvement of proteolysis in the process of tunic softening as well as cuticle regeneration. Using pure cultures of the causative flagellate A. hoyamushi, the expression of protease genes and secretion of some proteases were confirmed by RNA-seq analysis and a 4-methylcoumaryl-7-amide substrate assay. Some of these proteases may degrade proteins in the tunic matrix. These findings suggest that the proteases of A. hoyamushi is the key to understanding the mechanisms of cuticular regeneration inhibition and tunic softening.
期刊介绍:
DAO publishes Research Articles, Reviews, and Notes, as well as Comments/Reply Comments (for details see DAO 48:161), Theme Sections and Opinion Pieces. For details consult the Guidelines for Authors. Papers may cover all forms of life - animals, plants and microorganisms - in marine, limnetic and brackish habitats. DAO''s scope includes any research focusing on diseases in aquatic organisms, specifically:
-Diseases caused by coexisting organisms, e.g. viruses, bacteria, fungi, protistans, metazoans; characterization of pathogens
-Diseases caused by abiotic factors (critical intensities of environmental properties, including pollution)-
Diseases due to internal circumstances (innate, idiopathic, genetic)-
Diseases due to proliferative disorders (neoplasms)-
Disease diagnosis, treatment and prevention-
Molecular aspects of diseases-
Nutritional disorders-
Stress and physical injuries-
Epidemiology/epizootiology-
Parasitology-
Toxicology-
Diseases of aquatic organisms affecting human health and well-being (with the focus on the aquatic organism)-
Diseases as indicators of humanity''s detrimental impact on nature-
Genomics, proteomics and metabolomics of disease-
Immunology and disease prevention-
Animal welfare-
Zoonosis