Hydrogen peroxide produced by some bacteria causes DNA
double-strand breaks, cell suicide.
(June 15, 2015) A
bacterium that is the most common cause of pneumonia — a leading cause of death
worldwide — can damage DNA in lung cells, a new study has shown.
Researchers from the Singapore-MIT Alliance for Research and
Technology (SMART) demonstrated that hydrogen peroxide secreted by some strains
of Streptococcus pneumoniae causes DNA in human lung cells to suffer
double-strand breaks. Such breaks sever the DNA, creating broken ends that are
highly toxic to cells, leading to cell suicide, or apoptosis.
“Secretion of hydrogen peroxide damages the DNA of lung
cells, crippling the lungs' defenses against invasion and making it easier for
the bacteria to get into the bloodstream,” says Bevin Engelward, the paper’s
senior author and a professor of biological engineering at MIT.