Engineered Bacteria Die For the Good of Others
Bacteria have been engineered to test the evolutionary wisdom behind Spock’s dying words, “the needs of the many outweigh the needs of the few.” Though bacteria will never have to give their lives to save the starship Enterprise from the wrath of Khan, understanding why some bacteria kill themselves to benefit others could help doctors fight infections so that more humans might live long and prosper.
“Overall our results fill in a conceptual gap in understanding the evolutionary dynamics of programmed bacterial death during stress and have implications for designing intervention strategies for effective treatment of bacterial infections with antibiotics,” said Lingchong You of Duke University and senior author of the study published in Molecular Systems Biology, in a press release.
You’s team of biologists engineered a strain of Escherichia coli bacteria to respond to undergo apoptosis, or programmed cell death, when triggered by the scientists. The engineered bacteria now contain a gene that causes them to commit cellular suicide when exposed to a certain antibiotic. The bacteria also contain a gene which can be activated to cause them to produce an enzyme which will protect surviving E. coli from being destroyed by the antibiotic. However the enzyme can only escape the engineered E. coli when they rupture and make the ultimate sacrifice for their bacterial brethren.
“Our results clearly demonstrate that it is possible to have conditions where the death of some bacteria confers an advantage for the overall population of bacteria,” said You. “The system is tunable which means that the extent of altruistic death in the bacterial population can be increased. We are therefore able to control the extent of programmed cell death as well as test the benefits of altruistic death under different conditions.”
Colorized E. Coli (Mattosaurus, Wikimedia Commons)