Sulfide, microcystin, and the etiology of black band disease
| Autor: | Raju Sekar, Laurie L. Richardson, Emily Broderick, Miroslav Gantar, Dina Stanić, Aaron W. Miller, Longin T. Kaczmarsky |
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| Jazyk: | angličtina |
| Rok vydání: | 2009 |
| Předmět: |
Cyanobacteria
Sulfide Microcystins Coral Microcystin Aquatic Science Biology Sulfides Article Microbiology medicine polycyclic compounds Animals Microbial mat skin and connective tissue diseases Ecology Evolution Behavior and Systematics chemistry.chemical_classification fungi technology industry and agriculture Black band disease Cyanotoxin biology.organism_classification medicine.disease Anthozoa chemistry Marine Toxins Bacteria |
| Popis: | Black band disease (BBD) consists of a cyanobacterial dominated, sulfide-rich microbial mat that migrates across coral colonies degrading coral tissue. The mat contains diverse bacteria that include photoautotrophs (cyanobacteria), sulfate-reducers, sulfide-oxidizers, and organoheterotrophs. It is known that BBD sulfate-reducers contribute to BBD pathobiology by production of sulfide, which causes coral tissue lysis and death, and that the cyanotoxin microcystin is produced by BBD cyanobacteria. In this study we used a model system of coral fragments to investigate the roles of sulfide and microcystin in BBD by exposure to the metabolic inhibitors Na molybdate and DCMU (3-(3’,4’-dichlorophenyl)-1,1-dimethylurea), which inhibit sulfate reduction and oxygenic photosynthesis respectively. Exposure of BBD inocula to Na molybdate prior to inoculation prevented infection of healthy fragments but did not prevent continued band migration and coral tissue lysis by previously inoculated BBD infections. Exposure to DCMU did not inhibit either the initiation of BBD or continued migration of active BBD. Exposure of healthy coral fragments to sulfide, purified microcystin, and a combination of both revealed that both microcystin and sulfide are toxic to coral and act synergistically. Exposure of bacteria isolated from BBD and the healthy coral surface mucopolysaccharide layer (SML) revealed that relatively more BBD isolates were stimulated by microcystin compared to coral SML isolates, although effects were not uniform and the majority exhibited no effect. Our results indicate that sulfide is required for initiation of BBD, that microcystin and sulfide induce coral tissue degradation, and that bacteria from healthy coral and BBD respond differently to microcystin. |
| Databáze: | OpenAIRE |
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