Exploring Internal Chemistry of Bacterial Predation from External Measurements

Abstract

Bdellovibrio bacteriovorus is a gram negative bacteria that preys on all other gram negative cells. This is done by the Bdellovibrio bacteriovorus snuggling up against the prey cell, releasing enzymes to break down the outer of the two membranes, and getting inside to propagate within the periplasmic space of the host. This latter phase of the Bdellovibrio bacteriovorus? life cycle is known as a bdelloplast. These bdelloplasts have been imaged with atomic force microscopy (AFM) in order to investigate the physical changes induced by the consumption of the prey. Previous research indicated that E. coli, a gram negative cell, will form the expected rounded bdelloplast when killed by UV exposure before being consumed by Bdellovibrio bacteriovorus, but that heat killed E. coli will not. It is on the ZK1056 strain of E. coli that we have been inducing different kill times and conditions before feeding them to the 109J strain of Bdellovibrio bacteriovorus. When this strain of E. coli is heat treated, it is difficult to distinguish cells due to induced changes in the E. coli surface. The UV treated E. coli quickly loses its ability to replicate but has proven difficult to kill with a 95% efficiency. However, the UV treated cells are easily imaged with AFM.