Tissue abscission and wound healing in the operculum of Pomatoceros lamarckii Quatrefages (Polychaeta: Serpulidae)

Abstract

Following opercular amputation in Pomatoceros lamarckii Quatrefages, wound healing is initiated from a predetermined point on the peduncle. The events of abscission, cell migration and cuticle deposition during wound healing have been studied by light and electron microscopy. Abscission occurs at a predetermined point on the peduncle indicated by specialized epidermal cells, the easy break‐point cells (EBP). Following detachment of tissues distal to the EBP cells, the resultant wound is plugged by a knot of coelomocytes which provide a substratum over which epidermal cells migrate to seal and restore the epidermis. During their migration, the epidermal cells undergo differentiation and deposit a new cuticle. Cuticle formation is initiated by the deposition of a finely filamentous matrix. The fine filaments subsequently coalesce to form thicker fibrils which become aggregated into layers of orthogonally‐arranged fibril bundles. The mechanisms involved in abscission, cell migration and cuticle deposition during wound healing of the opercular filament are discussed.

A Revised Spiralian Homeobox Gene Classification Incorporating New Polychaete Transcriptomes Reveals a Diverse TALE Class and a Divergent Hox Gene

“…S. lamarcki can completely regrow the operculum over the course of about 2 weeks after removal by dissection or its own autotomic response to attack. The regenerative process is comprised of the proliferation-less morphallactic remodeling of the tissue underlying the wound into the distal cup and plate region of the operculum, and the growth of the opercular filament from the intermediate tissue ( Bubel and Thorp 1985 ; Szabó and Ferrier 2014 ). This process differs from stereotypical annelid caudal regeneration in lacking a blastema and in having a distal, rather than proximal, morphallactic component.…”

Cell proliferation dynamics in regeneration of the operculum head appendage in the annelid Pomatoceros lamarckii

“…The morphogenesis of the P. lamarckii operculum during regeneration follows a stereotyped sequence of events. Bubel and Thorp () noted that the opercular filament regenerates without a blastema. Our observations agree with this assessment.…”

“…Both structures regenerate rapidly when lost, and are commonly seen regenerating in wild‐collected worms (personal observation), consistent with their importance to the animal. Preliminary descriptions of the histology of intact and regenerating opercular filaments in P. lamarckii have been previously provided (Hanson, ; Bubel et al, , , '85; Bubel and Thorp, ). Here we establish the time‐course of opercular regeneration using a large sample of worms, and describe cell proliferation patterns during regeneration.…”