The discovery was made in Toxoplasma gondii, an organism that can cause blindness and brain damage in people with an impaired immune system and can cause severe disease in first trimester fetuses. In addition, the organism is used as a model experimental system for studying the closely related mosquito-borne malaria parasite Plasmodium.

"The way these organisms move and the way their movement is controlled is absolutely critical to their ability to cause disease," said Dr. Con Beckers, associate professor of cell and developmental biology at UNC's School of Medicine.

"Movement is necessary for these parasites to spread within the host animal, it is necessary for their ability to enter host cells, and movement is also necessary for parasites to escape from the host cell, to swim off and find a new cell."

A report of the research appeared in the May 10 issue of the Journal of Cell Biology. Co-authors are Beckers, Elizabeth Gaskins, Nicollete DeVore and Tara Mann, all of UNC; and Stacey Gilk and Gary Ward, of the University of Vermont.

The research will have relevance to malaria and a variety of related pathogens including Cryptosporidium, which causes disease in the elderly and in people with AIDS.

Protozoan parasites in the phylum that includes Toxoplasma and Plasmodium normally lack external structures such as hairlike cilia, pseudopodia and whiplike flagella for movement, the report said. Instead, their movement is through a unique process called gliding motility - a circular and forward twisting movement - that remains poorly defined, the scientists said.

In an attempt to understand the parasite's movement machinery, the study team began by characterizing the protein composition of the organism'
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Contact: Leslie H. Lang
llang@med.unc.edu
919-843-9687
University of North Carolina School of Medicine
21-May-2004