Dysentery’s life raft

Katie Ward and Neil Caudle

In regions with poor sanitation, amoebic dysentery delivers gut-wrenching misery to about 50 million people worldwide. The perpetrator is a protozoan, Entamoeba histolytica, one of the world’s top three parasitic killers.

“Approximately two point six billion people worldwide do not use modern sanitation practices, and eight hundred and eighty-six million do not have access to clean water,” says Lesly Temesvari, pro­fessor of biological sciences. “The risk for getting this disease is substantial.”

With thirteen years of sustained fund­ing from the National Institutes of Health and the National Science Foundation, Temesvari has been studying the biology of Entamoeba, probing for a weakness in its complex cycle of life. She has found, in a membrane that surrounds the parasite, one likely suspect: cholesterol-rich areas known as lipid rafts. Apparently, Ent­amoeba uses proteins in the rafts to thrive, reproduce, and attack its host.

Temesvari’s lab is connecting the dots in a chain of events that lead to amoebic dysentery. The parasite, she explains, secretes proteins that degrade the mucous lining of a human intestine, which allows them to adhere to the host’s intestinal cells. This adhesion triggers biochemical reactions in the parasite that rely on the parasite’s rafts, an attack that eventually perforates the intestine, giving the parasite entrance to the circulatory system. Once in the bloodstream, Entamoeba can infect the liver, brain, and lungs.

In a related project, Temesvari’s lab has found that bubble-like vesicles within cells traffic proteins between parasite and host. “We are trying to understand the molecules that assist in this trafficking,” she says.

Sorting out such molecular mechanics may help Temesvari and her colleagues find ways to prevent infection or interfere with the parasite’s progress. Because some of the Entamoeba’s lipid-raft proteins differ from those in humans, it may be possible to target the parasite’s proteins without harm to the host.

“I am hoping that we may be able to identify some target for a vaccine or a new drug or therapy,” she says.

The effort will get a boost this year, as Temesvari moves her lab into Clemson’s new life sciences building, whose top floor will be devoted to studies of Entamoeba and other parasites enclosed within membranes. The move will help Temesvari interact with colleagues Kerry Smith and Cheryl Ingram-Smith, both of whom also study Entamoeba.

“Being in close proximity with these scientists will be very beneficial for all of us,” she says.

Lesly A. Temesvari is a professor of biologi­cal sciences, College of Agriculture, Forestry, and Life Sciences. Kerry Smith is a professor and Cheryl Ingram-Smith is an assistant profes­sor, both in genetics and biochemistry, College of Agriculture, Forestry, and Life Sciences. For more on Lesly Temesvari’s work, read In science, creativity is at first hypothetical.

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