Bacteria don't just swim about randomly. Rather, they aim to find "good" environments and avoid "bad" ones. For example, they seek nutritious chemicals and shun noxious ones. This aspect of behavior is called "chemotaxis." Chemotaxis is the movement of organisms toward or away from chemicals. The major objective of this research is to try to understand the mechanism of chemotaxis. How do bacteria sense the chemicals that attract or repel them? How is the sensed information translated into action? How are the flagella told what to do? How do flagella work and how are they coordinated? The mechanism of motility is thus involved here too. The tools of biochemistry and genetics will be applied to try to answer these questions. We have previously discovered that methionine is required for bacterial chemotaxis and that it functions by methylating proteins. We are now aiming to learn how these methylated proteins work in the chemotactic mechanism.