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Abstracts
Workgroup: Frontiers in Disease Research
Extracellular Proteins from Perkinsus marinus: Analysis of Pathogenic Mechanisms and Development of Enhanced Diagnostics.
Principal Investigator(s):
Dr. Mohamed Faisal, Department of Environmental Sciences, School of Marine Science/Virginia Institute of Marine Science, The College of William and Mary, faisal@ahdl.msu.edu
Co-Investigator(s):
Drs. S.L. Kaattari and J.F. La Peyre, Department of Environmental Sciences, School of Marine Science/Virginia Institute of Marine Science, The College of William and Mary
Funding Period: 1995
- Axenic cultures were initiated, for the first time, from Perkinsus marinus.
- In order to define extracellular products of P. marinus, a protein-free chemically defined culture medium was developed.
- It has been demonstrated that P. marinus secretes potent chymotrypsin-like serine proteases in vitro. These proteases have been identified, isolated, and characterized.
- Extracellular products of P. marinus play major roles in the disease initiation and propagation. These products favor the propagation of the protozoan in vivo by suppressing and compromising oyster defense mechanisms.
- Chemotherapeutants with protease inhibitory activities, such as bacitracin, inhibit P. marinus propagation in vitro and in vivo.
- In Dr. Kaattari's lab, a number of monoclonal antibodies were developed. These antibodies recognized P. marinus extracellular products in vivo.
IMPACTS and/or BENEFITS:
This project has laid the foundation for our current understanding of the major disease processes involved in P. marinus infection. Continuous cultures of P. marinus became available for the first time and allowed investigations that would have been otherwise impossible to pursue. A number of growth media have been developing thus allowing the biochemical characterization of P. marinus extracellular secretions.
The identification of P. marinus extracellular products particularly those exhibiting serine protease properties led to the elucidation of pathogenic mechanisms adopted by P. marinus. Chemotherapeutants based on protease inhibition appears to be promising and deserves further investigations. A sensitive ELISA assay employing the monoclonal antibodies, developed by Dr. Kaattari, could be successfully applied in epidemiological surveys.
PROJECT PUBLICATIONS:
Ottinger, C.A., T. D. Lewis, D. A. Shapiro, M. Faisal, and S. L. Kaattari (2001): Detection of Perkinsus marinus extracellular proteins the tissues of the eastern oyster (Crassostrea virginica):Potential use in diagnostic assays. Journal of Aquatic Animal Health 13:133-141.
Faisal, M., La Peyre, J.F, E.E. Elsayed, and C.L. Wright (1999). Bacitracin inhibits the oyster pathogen Perkinsus marinus in vitro and in vivo. J. Aquat. Animal Hlth.11: 130-138.
Faisal, M., D.Y. Schafhauser, K. A. Garreis, E.E. Elsayed and J.F. La Peyre (1999): Purification of Perkinsus marinus proteases using bacitracin-sepharose affinity chromatography. Comp. Biochem. Physiol. B. 123:417-426.
Tall, B.D., J.F. La Peyre, J.W. Bier, M.D. Miliotis, D.E. Hahes, M.H. Kothary, D.B. Shah, and M. Faisal (1999): Perkinsus marinus extracellular protease modulates survival of Vibrio vulnificus in eastern oyster (Crassostrea virginica) hemocytes. Appl. Environ. Microbiol. 65: 4261-4263.
La Peyre, J.F. and M. Faisal (1997): Development of a protein-free chemically defined culture medium for the propagation of the oyster pathogen Perkinsus marinus. Parasite 4: 67-73.
Garreis, K.A., J.F. La Peyre, and M. Faisal (1996): The effects of Perkinsus marinus extracellular products and purified proteases on oyster defense parameters in vitro. Fish Shellfish Immunol. 6: 581-597.
La Peyre, J.F., H. Yarnall, and M. Faisal (1996): Contribution of Perkinsus marinus extracellular products in the infection of eastern oysters (Crassostrea virginica) J. Invertebr. Pathol. 68:312-313.
La Peyre, J.F. and M. Faisal (1996): Optimal culture conditions for the propagation of the oyster pathogen Perkinsus marinus (Apicomplexa) in protein deficient medium. Parasite 3: 147-153.
La Peyre, J.F. and M. Faisal (1995): Perkinsus marinus produces extracellular proteolytic factor(s) in vitro. Bull. Eur. Assoc. Fish Pathol. 15:28-31.
La Peyre, J.F., D.Y. Schafhauser, E.M. Rizkalla and M. Faisal (1995): Production of serine proteases by the oyster pathogen Perkinsus marinus (Apicomplexa) in vitro. J. Euk. Microbiol. 42: 544-551.
La Peyre, J.F. and M. Faisal (1995): Improved method for the initiation of continuous cultures of the oyster pathogen Perkinsus marinus (Apicomplexa). Trans. Am. Fish. Soc. 124:144-146.
La Peyre, J.F., M. Faisal and E.M. Burreson (1993): in vitro propagation of the protozoan Perkinsus marinus, a pathogen of the eastern oyster, Crassostrea virginica. J. Euk. Microbiol. 40:304-310.
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