Robert J. Maier
Creative Research Medal 2004
Robert J. Maier, GRA-Ramsey Eminent Scholar in Microbial Physiology, is trying to uncover the processes that give bacteria the ability to cause disease in humans. He is a world leader in the study of hydrogenases – a class of enzymes important in bacterial energy metabolism. Dr. Maier’s lab recently discovered that a specific hydrogenase allows a stomach-colonizing bacterium to use hydrogen as its main energy source in culture. The bacterium, called Helicobacter pylori, is associated with peptic ulcers and stomach cancer and is found in half of all humans. Using microelectrodes, his team demonstrated that hydrogen in the stomach lining of living mice is available at levels to support bacterial growth. They also found that bacterial mutants lacking the hydrogen-utilizing enzyme were not able to colonize the stomach very well. This is the first evidence to show a role for hydrogen gas in pathogenesis. By using hydrogen as an energy source, the pathogen avoids competing with its host for nutrients and is able to flourish in a nutrient-poor environment. Since this hydrogenase is not found in humans, it may be a target for new antibiotics or other antimicrobial agents. Dr. Maier’s group now is testing the role of hydrogen gas in other pathogenic bacteria such as those linked to liver cancer, typhoid fever and food poisoning.