title: Apoptosis of hemocytes from lions-paw scallop Nodipecten subnodosus induced with paralyzing shellfish poison from Gymnodinium catenatum.
abstract: The toxic dinoflagellate Gymnodinium catenatum produces paralyzing shellfish poisons (PSPs) that are consumed and accumulated by bivalves. Previously, we recorded a decrease in hemocytes 24h after injection of PSPs (gonyautoxin 2/3 epimers, GTX2/3) in the adductor muscle in the lions-paw scallop Nodipecten subnodosus. In this work, qualitative and quantitative analyses, in in vivo and in vitro experiments, revealed that the lower count of hemocytes results from cells undergoing typical apoptosis when exposed to GTX 2/3 epimers. This includes visible morphological alterations of the cytoplasmic membrane, damage to the nuclear membrane, condensation of chromatin, DNA fragmentation, and release of DNA fragments into the cytoplasm. Induction of apoptosis was accompanied by phosphatidylserine exposure to the outer cell membrane and activation of cysteine-aspartic proteases, caspase 3 and caspase 8. Addition of an inhibitor of caspase to the medium suppressed activation in hemocytes exposed to the toxins, suggesting that cell death was induced by a caspase-dependent apoptotic pathway. The results are important for future investigation of the scallop's immune system and should provide new insights into apoptotic processes in immune cells of scallops exposed to PSPs.
authors.affiliation: Centro de Investigaciones Biológicas del Noroeste, S.C. (CIBNOR), Calle IPN #195, La Paz, B.C.S. 23096, Mexico. Electronic address: norma.estrada.munoz@gmail.com.
authors.forename: Norma
authors.initials: N
authors.lastname: Estrada
authors.affiliation: Centro de Investigaciones Biológicas del Noroeste, S.C. (CIBNOR), Calle IPN #195, La Paz, B.C.S. 23096, Mexico.
authors.forename: Felipe
authors.initials: F
authors.lastname: Ascencio
authors.affiliation: Centro de Investigación y de Estudios Avanzados del IPN (CINVESTAV), Av. Instituto Politécnico Nacional #2508, Mexico City, D.F. 07300, Mexico.
authors.forename: Liora
authors.initials: L
authors.lastname: Shoshani
authors.affiliation: Centro de Investigación y de Estudios Avanzados del IPN (CINVESTAV), Av. Instituto Politécnico Nacional #2508, Mexico City, D.F. 07300, Mexico. Electronic address: rcontrer@fisio.cinvestav.mx.
authors.forename: Rubén G
authors.initials: RG
authors.lastname: Contreras
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D001692:Biological Transport; D020169:Caspases / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D002470:Cell Survival; D053903:DNA Breaks, Double-Stranded / Q000187:drug effects; D004141:Dinoflagellida / Q000737:chemistry*; D004789:Enzyme Activation / Q000187:drug effects; D006434:Hemocytes / Q000187:drug effects* / Q000473:pathology; D006458:Hemolymph / Q000737:chemistry / Q000378:metabolism; D007267:Injections; D049897:Pectinidae / Q000187:drug effects*; D010718:Phosphatidylserines / Q000378:metabolism; D012530:Saxitoxin / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000737:chemistry / Q000633:toxicity
chemical_list: D010718:Phosphatidylserines; D012530:Saxitoxin; C013007:gonyautoxins; D020169:Caspases
keywords: Apoptosis; Gonyautoxin 2/3 epimers (GTX 2/3 epimers); Gymnodinium catenatum; Hemocyte; Nodipecten subnodosus; Paralyzing shellfish poisons