Morphological, Physiological and Mechanical Features of the Mutable Collagenous Tissues Associated with Autotomy and Evisceration in Dendrochirotid Holothuroids
Evisceration in dendrochirotid sea cucumbers leads to expulsion of the digestive tract, pharyrngeal complex and coelomic fluid through rupture of the anterior body wall. This process involves failure of three mutable collagenous tissue (MCT) structures, the introvert, the pharyngeal retractor muscle...
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| Format: | Article |
| Language: | English |
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MDPI AG
2023-02-01
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| Series: | Marine Drugs |
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| Online Access: | https://www.mdpi.com/1660-3397/21/3/134 |
| _version_ | 1797610493729308672 |
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| author | Maria Byrne |
| author_facet | Maria Byrne |
| author_sort | Maria Byrne |
| collection | DOAJ |
| description | Evisceration in dendrochirotid sea cucumbers leads to expulsion of the digestive tract, pharyrngeal complex and coelomic fluid through rupture of the anterior body wall. This process involves failure of three mutable collagenous tissue (MCT) structures, the introvert, the pharyngeal retractor muscle tendon, and the intestine-cloacal junction. These are complex structures composed of several tissue strata. The MCT in the three autotomy structures contains collagen fibrils, unstriated microfibrils, and interfibrillar molecules. Neurosecretory-like processes (juxtaligamental-type) with large dense vesicles (LDVs) are prominent in the autotomy structures. Biomechanical tests show that these structures are not inherently weak. Failure of the autotomy structures can be elicited by manipulating the ionic environment and the changes are blocked by anaesthetics. Autotomy and evisceration are under neural control, but local neural elements and neurosecretory-like processes do not appear to be a source of factors that cause MCT destabilisation. The LDVs remain intact while the tissue destabilises. The coelomic fluid contains an evisceration inducing factor indicating a neurosecretory-like mediation of autotomy. This factor elicits muscle contraction and MCT destabilisation. As the autotomy structures are completely or partially surrounded by coelomic fluid, the agent(s) of change may be located in the coelom (systemic origin) as well as originate from cells within the MCT. The biochemistry and mechanism(s) of action of the evisceration factor are not known. This factor is a promising candidate for biodiscovery investigation. |
| first_indexed | 2024-03-11T06:16:00Z |
| format | Article |
| id | doaj.art-26c9292262f14674be12875a5f20281b |
| institution | Directory Open Access Journal |
| issn | 1660-3397 |
| language | English |
| last_indexed | 2024-03-11T06:16:00Z |
| publishDate | 2023-02-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Marine Drugs |
| spelling | doaj.art-26c9292262f14674be12875a5f20281b2023-11-17T12:17:00ZengMDPI AGMarine Drugs1660-33972023-02-0121313410.3390/md21030134Morphological, Physiological and Mechanical Features of the Mutable Collagenous Tissues Associated with Autotomy and Evisceration in Dendrochirotid HolothuroidsMaria Byrne0School of Life and Environmental Sciences, University of Sydney, Sydney, NSW 2006, AustraliaEvisceration in dendrochirotid sea cucumbers leads to expulsion of the digestive tract, pharyrngeal complex and coelomic fluid through rupture of the anterior body wall. This process involves failure of three mutable collagenous tissue (MCT) structures, the introvert, the pharyngeal retractor muscle tendon, and the intestine-cloacal junction. These are complex structures composed of several tissue strata. The MCT in the three autotomy structures contains collagen fibrils, unstriated microfibrils, and interfibrillar molecules. Neurosecretory-like processes (juxtaligamental-type) with large dense vesicles (LDVs) are prominent in the autotomy structures. Biomechanical tests show that these structures are not inherently weak. Failure of the autotomy structures can be elicited by manipulating the ionic environment and the changes are blocked by anaesthetics. Autotomy and evisceration are under neural control, but local neural elements and neurosecretory-like processes do not appear to be a source of factors that cause MCT destabilisation. The LDVs remain intact while the tissue destabilises. The coelomic fluid contains an evisceration inducing factor indicating a neurosecretory-like mediation of autotomy. This factor elicits muscle contraction and MCT destabilisation. As the autotomy structures are completely or partially surrounded by coelomic fluid, the agent(s) of change may be located in the coelom (systemic origin) as well as originate from cells within the MCT. The biochemistry and mechanism(s) of action of the evisceration factor are not known. This factor is a promising candidate for biodiscovery investigation.https://www.mdpi.com/1660-3397/21/3/134sea cucumberMCTconnective tissuehistologyelectron microscopyEchinodermata |
| spellingShingle | Maria Byrne Morphological, Physiological and Mechanical Features of the Mutable Collagenous Tissues Associated with Autotomy and Evisceration in Dendrochirotid Holothuroids Marine Drugs sea cucumber MCT connective tissue histology electron microscopy Echinodermata |
| title | Morphological, Physiological and Mechanical Features of the Mutable Collagenous Tissues Associated with Autotomy and Evisceration in Dendrochirotid Holothuroids |
| title_full | Morphological, Physiological and Mechanical Features of the Mutable Collagenous Tissues Associated with Autotomy and Evisceration in Dendrochirotid Holothuroids |
| title_fullStr | Morphological, Physiological and Mechanical Features of the Mutable Collagenous Tissues Associated with Autotomy and Evisceration in Dendrochirotid Holothuroids |
| title_full_unstemmed | Morphological, Physiological and Mechanical Features of the Mutable Collagenous Tissues Associated with Autotomy and Evisceration in Dendrochirotid Holothuroids |
| title_short | Morphological, Physiological and Mechanical Features of the Mutable Collagenous Tissues Associated with Autotomy and Evisceration in Dendrochirotid Holothuroids |
| title_sort | morphological physiological and mechanical features of the mutable collagenous tissues associated with autotomy and evisceration in dendrochirotid holothuroids |
| topic | sea cucumber MCT connective tissue histology electron microscopy Echinodermata |
| url | https://www.mdpi.com/1660-3397/21/3/134 |
| work_keys_str_mv | AT mariabyrne morphologicalphysiologicalandmechanicalfeaturesofthemutablecollagenoustissuesassociatedwithautotomyandeviscerationindendrochirotidholothuroids |