Mycoplasma pneumoniae is a pathogenic species of bacteria responsible for up to two million cases of tracheobronchitis and atypical pneumonia every year, and also causes disease of the central nervous system and other anatomical sites. Although M. pneumoniae is unusual among bacteria because of its highly reduced genome and the absence of a cell wall, evidence suggests that like for many bacteria, M. pneumoniae biofilms are important in countering host defenses. Biofilms are three-dimensional formations composed of cells and material they secrete. A potentially significant characteristic of M. pneumoniae biofilms is reduced production of virulence factors, including hydrogen peroxide, which M. pneumoniae uses to damage host cells so that it can extract nutrients from them. Its enzyme glycerol 3-phosphate oxidase (GlpO) produces hydrogen peroxide during oxidation of glycerol 3-phosphate, a molecule ultimately derived from host cell membranes. We hypothesize that oxygen concentration, which is lower inside biofilm structures, is sensed and regulates the activity of GlpO. We tested the activity of GlpO in lysates from M. pneumoniae cells grown in regular and reduced oxygen environments by measuring hydrogen peroxide production from added glycerol 3-phosphate. Our results indicate a statistically significant 3-fold decrease in GlpO activity in lysates from bacteria grown in a 10% oxygen atmosphere as compared with cultures grown in ambient air, supporting our hypothesis. Future studies will aim to explore the mechanisms by which M. pneumoniae senses oxygen and regulates GlpO, providing information that could be used in the design of new therapeutic treatments that target these mechanisms.
Author(s): Ethan F. Boley, Zoe E. Dapore, Mitchell F. Balish, PhD.
Advisor(s): Mitchell Balish, Department of Microbiology
Zoe Dapore, Department of Microbiology