PAGE 4 OF 5
Tsetse Flies in the Alps
While Navarro’s work has focused on the trypanosome’s bloodstream-stage surface proteins, Isabel Roditi studies how the parasite regulates the expression of those proteins inside the gut and salivary glands of its vector, the tsetse fly. Of special interest is the parasite’s ability to sense its outside environment and respond with the appropriate adjustment of its surface coat.
“There is a complex interaction between the trypanosome and the fly as the parasites differentiate, reproduce, and migrate through different tsetse tissues,” says Roditi, an HHMI international research scholar at the University of Berne.
Using methods to genetically manipulate trypanosomes, Roditi’s team was surprised to discover that many of the large number of surface molecules on trypanosomes were not needed to grow the parasites in cultures. In addition, the researchers found that the function of the proteins became clear only when studied within the flies.
Further research led to an overhaul of the prevailing notion that abundant surface proteins, known as procyclins, were present in invariant form in every major stage of the parasite in the fly. Roditi’s lab found that procyclins are expressed only at certain times during the parasite’s progression through the fly’s gut—and not in the salivary glands.
Gloria Rudenko, a trypanosome expert at Imperial College London, says Roditi “has given us insight into the biology of the procyclin proteins that shield the trypanosome when it is in the gut of the tsetse fly insect vector.”
Penetrating the Armor
But what do those discoveries mean to the effort to treat or prevent African sleeping sickness, a devastating disease that Roditi became aware of as a child growing up in southern Africa?