Even though little is known for certain about the Gram-negative bacterium Bdellovibrio bacteriorvorous , it is emerging into microbiology labs all over the country. Its unique life cycle allows for many different types of studies. In this project, Bdellovibrio bacteriorvorous will be turned into a biosensor through reporter gene fusion in order to determine the osmotic environment of the periplasmic space of other Gram-negative bacteria, such as Escherichia coli . This is an important subject, as we know very little about the periplasmic space except that it plays a crucial role in cell function and growth. By monitoring the different levels of osmotically regulated proteins produced in Bdellovibrio while it is in growth phase, we hope to unravel some of the mystery surrounding the periplasmic space.