Genetically Engineered <i>Bacillus thuringiensis</i> Cells (IMAGE) University of California - Riverside Caption Photo shows genetically engineered Bacillus thuringiensis cells constructed in the laboratory to combine mosquito-killing proteins from different bacterial species. These new recombinant strains are much more potent than natural bacteria that are capable of killing the mosquitoes that transmit malaria, filariasis, and many viral diseases to humans. The bright oval structures are spores, and the angular gray structures to the left of the spores in each cell are crystals of the mosquito-killing proteins. Credit Federici lab, UC Riverside. Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.