Ithaca College

 Carina Chittim of Harvard University will Present Discovery of a gut bacterial phospholipase D that supports disease-associated choline metabolism

Tuesday, November 28th 12:10 pm in CNS 333

Pizza and Beverages Provided

 The planet Earth is home to trillions of microbes that play key roles in maintaining homeostasis of a diverse set of ecosystems. Of those diverse ecosystems, the human gut harbors an important microbial community that contributes to the overall health of the host. Bacteria produce small molecule metabolites that allow them to interact with host cells. Dietary choline is an essential nutrient that is required for various processes including neurotransmission, cell membrane maintenance, and liver function and its degradation by gut microbes has been connected with several diseases. Gut bacteria utilize choline as a carbon source, cleaving the carbon-nitrogen bond to form acetaldehyde, which is shunted into carbon metabolism, and trimethylamine (TMA), which as implications for the host. Bacterial production of TMA has been correlated to several human disease states including non-alcoholic fatty liver disease, diabetes, colon cancer, and atherosclerosis.

However, the majority of dietary choline is present in the form of ophosphatidylcholine (PC), and is currently unknown how gut microbes obtain free choline from this substrate. We have determined that PC is metabolized into TMA by gut microbes, through a choline intermediate via the activity of a phospholipase D (PLD) family enzyme present in microbial communities. We have characterized the biochemical activity of this enzyme as well as its essential role in PC degradation in a variety of human isolates. This bacterial activity represents a novel role for this enzyme family in the provision of a carbon source for survival. Targeting this enzyme may provide a new approach for modulating TMA production and therefore disease risk.

Individuals with disabilities requiring accommodations should contact Paula Larsen at plarsen@ithaca.edu or (607) 274-3238. We ask that requests for accommodations be made as soon as possible.