GLT-1, a glutamate transporter, soaks up glutamate (a neurotransmitter) released by neurons and converts it back into a safer substance. Toxoplasma gondii, a protozoan parasite about five microns long, infects a third of the world’s population. Ingested via undercooked meat or unwashed vegetables, the parasite infects 15-30 percent of the US population. In France and...