A SPECTROPHOTOMETRIC METHOD FOR MONITORING TACTIC RESPONSES OF BACTERIA UNDER ANAEROBIC CONDITIONS

A simple, inexpensive device called the chemotaxometer is described, which can be used inside an anaerobic chamber to assess tactic responses of bacteria to electron donors or accepters. The method employs a fiberoptic colorimeter probe inserted into a specially constructed tube containing a bacterial culture at a concentration of approximately 5 x 10(8) cells per ml. The chemical to be tested diffuses from an agar plug placed at the top of the tube. Changes in optical density are monitored for 30-60 min and used to quantitate the chemotactic response. This method has proven especially useful for the study of tactic responses to various electron accepters under anoxic conditions.