Amoebocytes and mesoglea of Corallimorpharia
Coral reefs are important yet sensitive ecosystems and regeneration is crucial for their health and survival. The mesoglea and amoebocytes are involved in regeneration and the morphology of corallimorphs provided an opportunity to investigate these structures using: laser capture microdissection; S-Trap proteomics and mass spectrometry; commercial polyclonal antibodies; and immunohistochemistry for immunolocalization. Filamin-A, calpain-9, and Rab7 antibodies may have utility as biomarkers in corals. Histopathology over 8 days in response to sterile necrosis was described for Ricordea florida and the response of R. florida and Rhodactis sp. to foreign bodies (various sized plastic microbeads) through ingestion was also investigated. Massive necrosis resulted in sequestration of necrotic material in acellular bands of mesoglea and eventual expulsion from the surviving coral. There was preferential ingestion (p < 0.05) of medium (150-180 μm) and large (212-250 μm) microbeads by R. florida and significantly more small microbeads ingested compared to Rhodactis sp.