Investigators and Program Directors

Research Interests

Darkfield micrograph of Treponema denticola, a spirochete bacterium associated with the development and progression of periodontitis.

Spirochetes are a unique group of spiral-shaped bacteria. These include pathogenic spirochetes that are the causative agents of syphilis and Lyme disease as well as non-pathogenic species that are used as models to study pathogenic spirochetes. Our model organism, Treponema denticola is associated with periodontal disease. Our earlier studies have focused on motility and structural genes because of their important role in the pathogenesis of spirochetes. We participated in pioneering efforts to establish the role of key motility genes using a genetic approach. We also utilized cryoelectron microscopy to establish the first detailed description of the native structure of T. denticola. More recently we established a collaboration to understand the role of non-heme iron-containing enzymes in determining the cellular response to oxidative and nitrosative stress.  Knockout mutants of T. denticola that are deficient in potential stress response polypeptides were created using allelic exchange. These mutants are being analyzed for deficiencies in stress response mechanisms. Disruption of the ability of spirochetes to move, grow or tolerate aerobic stresses may prove to be an effective vaccine strategy.

Schematic diagram showing the spirochete flagellum.

My career at the Wadsworth Center has also involved extensive public health activities. I have directed both the Sexually Transmitted Disease Laboratory and the Bacteriology Laboratories as well as holding the administrative position of Laboratory Chief of Bacterial Diseases. Currently, as Director of Infectious Diseases, I am administratively involved in overseeing the activities of this Division as well continuing basic research studies.

Contact Information

E-mail:limberg@wadsworth.org