Scientists studying a cunning parasite that has commandeered the cells of almost half the world's human population have begun to zero in on the molecular signals that must be severed to free the organism's cellular hostages.
While Toxoplasma gondii is not as widely known by the public as some of its more notorious parasitic brethren, it has been hijacking the cells of human and animal hosts for eons and is particularly dangerous to those with compromised and/or underdeveloped immune systems.
"We have understood for some time now that Toxoplasma can co-opt the biological processes of its host cell, but there's still a lot we don't know about how this happens and what benefit the parasite derives," said Dr. Amos Orlofsky at Albert Einstein College of Medicine of Yeshiva University, one of the co-authors of a new paper in the Journal of Biological Chemistry that reveals how blocking certain signals within a cell can liberate it from its captor.
Toxoplasma is a crafty single-celled organism that typically begins its life cycle in the warm body of a small mammal, such as a rat. While there, it reprograms the rat's gut instinct to avoid cats and, thus, makes the rat far more likely to get gobbled up. Toxoplasma's ultimate goal is, in fact, to get eaten by a cat, because, once it settles into the feline's gastrointestinal tract, it begins the second stage of its life cycle: laying the next generation of eggs that will be shed in feces and acquired by the next rat.
Seeing as how humans usually aren't eaten by cats, Toxoplasma doesn't seek them out as hosts. But, humans are exposed to the parasite at a fairly high rate, usually while changing cat litter or eating unwashed vegetables or undercooked meat.
"Toxoplasma is a major cause of mortality in AIDS patients worldwide, and it's also a serious problem for transplant recipients and for infants whose mothers became infec
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American Society for Biochemistry and Molecular Biology