DESPITE ITS POTENTIAL TO AFFECT THE BRAIN IN CHILDREN AND BABIES, CHLORPYRIFOS IS A COMMONLY USED PESTICIDE (7 MILLION POUNDS ANNUALLY) FOR FRUITS AND VEGETABLES (E.G., APPLES, PEACHES, BELL PEPPERS). OTHER PESTICIDES (SIMILAR TO CHLORPYRIFOS) HAVE BEEN SEEN TO KILL CERTAIN BACTERIA IN THE GUT MICROBIOME AND, CONSEQUENTLY, NEGATIVELY AFFECT HUMAN HEALTH.THE GUT MICROBIOME, WHICH IS A COLLECTION OF BACTERIA LIVING IN OUR GUT TO HELP US DIGEST FOOD, IS IMPORTANT TO OVERALL HUMAN HEALTH. NO STUDIES HAVE INVESTIGATED THE EFFECT OF CHLORPYRIFOS ON THE GUT MICROBIOME AT DOSES SIMILAR TO THE AMOUNT OF CHLORPYRIFOS SEEN ON FRUIT AND VEGETABLES AVAILABLE AT STORES. THIS STUDY USES A MULTI-DISCIPLINARY APPROACH TO COMPLETELY UNDERSTAND THE IMPACT OF CHLORPYRIFOS IN WILD TYPE MICE. MICE ARE COMMONLY USED AS A MODEL ORGANISM AND THE RESULTS FROM THESE STUDIES ARE USED TO MAKE INFERENCES ABOUT HUMAN HEALTH. I WILL TEST THE HYPOTHESIS THAT THE SMALL LEVELS OF CHLORPYRIFOS SEEN ON FRUITS AND VEGETABLES WILL PROMOTE AN IMPAIRED GUT MICROBIOME, LEAD TO INCREASED INFLAMMATION IN THE GUT, AND EXACERBATE THE EFFECTS OF OBESITY. NEW TECHNIQUES WILL BE USED TO DIRECTLY INVESTIGATE THE DAMAGE TO THE BACTERIA IN THE MICROBIOME, WHAT PRODUCTS THE BACTERIA ARE MAKING IN THE GUT, AND HOW THESE PRODUCTS CHANGE AFTER EXPOSURE TO CHLORPYRIFOS. TOGETHER, THESE RESULTS WILL ILLUSTRATE THAT CHLORPYRIFOS EXPOSURE PROMOTES DETRIMENTAL MODULATION OF THE GUT MICROBIOME.