Researchers find ancient mechanisms propel modern parasites

Finding cures and new treatments for diseases seems to be a unique eschelon of highly-informed scientific detective work, as this new finding published by Franklin College researchers demonstrates:

Long ago, when life on Earth was in its infancy, a group of small single-celled algae propelled themselves through the vast prehistoric ocean by beating whip like tails called flagella. It's a relatively unremarkable tale, except that now, more than 800 million years later, these organisms have evolved into parasites that threaten human health, and their algal past in the ocean may be the key to stopping them.

The organisms are called apicomplexa, but people know them better as the parasites that cause malaria and toxoplasmosis, serious diseases that infect millions of people every year, particularly in the developing world.

Now, researchers at the University of Georgia have discovered how an important structure inside these parasitic cells, which evolved from the algal ancestor millions of years ago, allows the cells to replicate and spread inside their hosts. Their research may soon lead to new therapies to halt these deadly pathogens before they cause disease.

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In their study, published Dec. 11 in PLoS Biology, the researchers demonstrate that, during the process of replication, the parasite cell loads genetic material into its daughter cells via a strand of fiber that connects the two. By altering the genes for the components of the fiber in the laboratory, the researchers discovered that they could prevent parasite replication, making the parasite essentially harmless.

"These altered parasites can initially infect cells, but once we turn off the fiber genes, they cannot create new daughter cells and spread," said Maria Francia, lead author and doctoral candidate in the department of cellular biology. "Since it cannot replicate, the parasite eventually dies without causing serious harm."

This replication fiber appears to have evolved from the flagellum that ancient algae used to swim.

"This was a surprising finding," said Boris Striepen, a Georgia Research Alliance Distinguished Investigator in UGA's Center for Tropical and Emerging Global Diseases. "These parasites no longer use flagella to swim, but they have apparently repurposed this machinery to now organize the assembly of an invasive cell."

Expertise developed by scientists at this level becomes some of the most valuable intellectual property on campus -  informed intuition - and one of our strengths is that as part of their work, scientists collaborate with younger researchers and doctoral candidates to pass on and perpetuate these professional habits. Congratulations to Francia and Dr. Striepen on this new work and the hope it holds for better treatments and thearapies.

Image: Boris Striepen, a Georgia Research Alliance Distinguished Investigator in UGA's Center for Tropical and Emerging Global Diseases, and cellular biology doctoral candidate Maria Francia.