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Proyectos de Investigación 2008-2010
Asperigillosis Disease of Sea Fans: Pathogens, Environment and Stress
Dr. Paul Bayman is the PI for R-92-1-04. This project seeks to advance understanding about the causal agents, physiological responses and environmental factors contributing to aspergillosis disease in the sea fan Gorgonia ventalina. The species is an important member of shallow marine hard-bottom habitats and massive die-offs have occurred in recent years. Although the project has ended, the thesis work continues and publications are in preparation and review.
Three graduate students have been working on different aspects of Aspergillus occurrence, and relation of aspergillosis disease to atmospheric dust and increased turbidity from river run-off. Two students graduate this year (2008) and the third in 2009. The work of these students under the guidance of Dr. Bayman deals with some of the more important findings of this study:
- Carlos Toledo will be graduating this year. His PhD thesis looks at the diverse fungal communities in diseased and healthy sea fan tissue.
- Anabella Zuluaga is also expected to graduate in 2008. Her PhD thesis characterizes genetic traits among different stains of Aspergillus.
- Luis Ramirez is expected to graduate in 2009. His thesis is to be determined.
The significant contributions from this Sea Grant study include the following:
Sea Grant research challenges current beliefs about aspergillosis disease of sea fans. Aspergillosis is a recently discovered disease affecting sea fans in the (Gorgonia spp.). The disease is widespread in the Caribbean, and many aspects have been studied. All of these studies rely on two papers published in Nature that reported the pathogen of aspergillosis to be Aspergillus sydowii. Sea Grant research has shown that this is an oversimplification: there are many potential pathogens, and they are opportunistic. This suggests that detecting the source of the pathogen is less important than the health of the host, and that some of the existing literature needs to be reevaluated. Sea Grant-funded researchers are now testing the effect of stress on the development of the disease.
Sea Grant research shows for the first time that marine strains of the fungus Aspergillus flavus produce aflatoxins. Aflatoxins are potent carcinogens that also affect the immune systems of many animals; they are a serious concern in agriculture and public health, and billions of dollars worth of commodities are discarded because of aflatoxin contamination. Strains of the fungus isolated from diseased sea fans have now been shown to produce this toxin. A few of these A. flavus strains produce aflatoxins in seawater-based medium, so it is possible that they are produced in infected sea fans and contribute to the disease.
Publications
Bayman P, Baker JL. 2006. Ochratoxins: a global perspective. Mycopathologia 162: 215-233
Toledo-Hernández C, Bones-González A, Ortiz-Vázquez OE, Sabat AM, Bayman P. 2007. Fungi in the sea fan Gorgonia ventalina: diversity and sampling strategies. Coral Reefs 26:725-730.
Planned publications
Rodríguez JA, Zuluaga-Montero A, Bayman P. Aflatoxin production by Aspergillus flavus isolated from Gorgonia ventalina infected with aspergillosis. In prep. for submission to Mycopathologia.
Toledo-Hernández C, Zuluaga A, Bones-González A, Rodríguez JA, Sabat AM, Bayman P. Fungal communities in healthy and diseased sea fans (Gorgonia ventalina). In prep. for submission to Coral Reefs.
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