1. Department of Microbiology, University of Mississippi, Jackson, Mississippi 39216, USA
2. U.S. Fish and Wildlife Service, National Fish Health Research Laboratory, Rt. 3, Box 700, Kearneysville, West Virginia 25430, USA
3. National Cancer Institute, Frederick Cancer Research Facility, P.O. Box B, Frederick, Maryland 21701, USA
4. Department of Biology, Fordham University, Rose Hill Campus, New York, New York 10458, USA