title: Effects of toxic compounds in Montipora capitata on exogenous and endogenous zooxanthellae performance and fertilization success.
abstract: Studies have identified chemicals within the stony coral genus Montipora that have significant biological activities. For example, Montiporic acids A and B and other compounds have been isolated from the adult tissue and eggs of Montipora spp. and have displayed antimicrobial activity and cytotoxicity in cultured cells. The ecological role of these toxic compounds is currently unclear. This study examines the role these toxins play in reproduction. Toxins were found in the eggs and larvae of the coral Montipora capitata. Releasing these toxins by crushing both the eggs and larvae resulted in irreversible inhibition of photosynthesis in endogenous and exogenous zooxanthellae within minutes. Moreover, these toxins were stable, as frozen storage of eggs and larvae did not affect toxicity. Photosynthetic competency of Porites compressa zooxanthellae treated with either frozen or fresh, crushed eggs was inhibited similarly (P > 0.05, ANCOVA). Addition of toxic eggs plugs to live P. compressa fragments caused complete tissue necrosis under the exposed area on the fragments within 1 week. Small volumes of M. capitata crushed eggs added to sperm suspensions reduced in vitro fertilization success by killing the sperm. After 30 min, untreated sperm maintained 90 ± 1.9% SEM motility while those treated with crushed eggs were rendered immotile, 4 ± 1.4% SEM. Flow cytometry indicated membrane disruption of the immotile sperm. Fertilization success using untreated sperm was 79 ± 4% SEM, whereas the success rate dropped significantly after exposure to the crushed eggs, 1.3 ± 0% SEM. Unlike the eggs and the larvae, M. capitata sperm did not reduce the photosynthetic competency of P. compressa zooxanthellae, suggesting the sperm was nontoxic. The identity of the toxins, cellular mechanism of action, advantage of the toxins for M. capitata and their role on the reef are still unknown.
authors.affiliation: Department of Reproductive Sciences, Smithsonian Conservation Biology Institute- National Zoological Park, Washington, District of Columbia, United States of America; Hawai'i Institute of Marine Biology, University of Hawaii, Kaneohe, Hawaii, United States of America.
authors.forename: Mary
authors.initials: M
authors.lastname: Hagedorn
authors.affiliation: Department of Reproductive Sciences, Smithsonian Conservation Biology Institute- National Zoological Park, Washington, District of Columbia, United States of America; Hawai'i Institute of Marine Biology, University of Hawaii, Kaneohe, Hawaii, United States of America.
authors.forename: Ann
authors.initials: A
authors.lastname: Farrell
authors.affiliation: Department of Reproductive Sciences, Smithsonian Conservation Biology Institute- National Zoological Park, Washington, District of Columbia, United States of America; Hawai'i Institute of Marine Biology, University of Hawaii, Kaneohe, Hawaii, United States of America.
authors.forename: Virginia
authors.initials: V
authors.lastname: Carter
authors.affiliation: Department of Reproductive Sciences, Smithsonian Conservation Biology Institute- National Zoological Park, Washington, District of Columbia, United States of America; Hawai'i Institute of Marine Biology, University of Hawaii, Kaneohe, Hawaii, United States of America.
authors.forename: Nikolas
authors.initials: N
authors.lastname: Zuchowicz
authors.affiliation: Hawai'i Institute of Marine Biology, University of Hawaii, Kaneohe, Hawaii, United States of America.
authors.forename: Erika
authors.initials: E
authors.lastname: Johnston
authors.affiliation: Hawai'i Institute of Marine Biology, University of Hawaii, Kaneohe, Hawaii, United States of America.
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Padilla-Gamiño
authors.affiliation: Smithsonian Marine Station, Fort Pierce, Florida, United States of America.
authors.forename: Sarath
authors.initials: S
authors.lastname: Gunasekera
authors.affiliation: Smithsonian Marine Station, Fort Pierce, Florida, United States of America.
authors.forename: Valerie
authors.initials: V
authors.lastname: Paul
mesh_terms: D000818:Animals; D037421:Anthozoa / Q000502:physiology*; D045424:Complex Mixtures / Q000737:chemistry / Q000633:toxicity; D005306:Fertilization / Q000187:drug effects; D008387:Marine Toxins / Q000378:metabolism* / Q000633:toxicity*; D012098:Reproduction
chemical_list: D045424:Complex Mixtures; D008387:Marine Toxins