Holothurian survival strategies: mechanisms for the maintenance of a bacteriostatic environment in the coelomic cavity of the sea cucumber, Parastichopus californicus.
The antibacterial responses of the coelomocytes and coelomic fluid of Parastichopus californicus to nine different species of marine bacteria were observed in vivo and in vitro. Five of the nine species of bacteria were cultured from P. californicus gut contents. Strong responses were directed against the bacterial species from the gut. Most bacteria agglutinated in coelomic fluid. Coelomocytes phagocytized and/or encapsulated the bacteria and showed a positive reaction for the lysosomal enzyme, acid phosphatase. Cell-free coelomic fluid exhibited less bactericidal activity against all of the marine species of bacteria than did complete coelomic fluid. Brown bodies, formed by coelomocytes surrounding foreign material, accumulated in the posterior region of the animal around the cloacal suspensors; these eventually were eliminated through a ringlet of ducts connecting the coelomic cavity with the external environment. Whole coelomic fluid inactivated endotoxin in vitro, but endotoxin did not initiate any detectable changes in the coelomocytes or coelomic fluid. Strong antibacterial response to the gut-associated bacterial species may well be essential to the survival of these animals, since during their seasonal visceral atrophy, gut-associated bacteria escape into the coelomic cavity.
D000818:Animals; D001419:Bacteria / Q000302:isolation & purification; D001826:Body Fluids / Q000502:physiology; D002329:Carmine / Q000378:metabolism; D004064:Digestive System / Q000166:cytology / Q000382:microbiology; D004068:Digestive System Physiological Phenomena; D004447:Echinodermata / Q000502:physiology*; D011506:Proteins / Q000032:analysis; D012616:Sea Cucumbers / Q000382:microbiology / Q000502:physiology*
D011506:Proteins; D002329:Carmine