Scientists have prepared a gut punch for one of humanity's greatest foes. Researchers at Johns Hopkins University announced today that they have bioengineered a microbe found in mosquito guts to attack and disable the malaria parasite. The modified bug inhibited the development of the parasite by up to 98 percent in mosquitoes while posing little risk to the insect or its prey, according to a study published in the Proceedings of the National Academy of Sciences.