Measuring attachment force of B. bacteriovorus over short time scales

Abstract

The goal of this research is to examine the attachment of the predatory bacteria known as Bdellovibrio bac-teriovorus onto its prey bacteria, Escherichia coli, and to increase the understanding of the B. bacteriovorus predatory process. B. bacteriovorus is being considered for predatory therapy, an alternative to antibiotics. Predatory therapy is the use of predatory bacteria to target pathogens in the body. The B. bacteriovorus has a hair-like protien filaments known as type IV pili that are believed to be the cause of the attachment. The pili extend and attach to the bacterium’s prey, then pull the predatory bacterium into its prey where it transitions from its attack phase into its reproductive phase. We utilized optical tweezers to facilitate attachment of a trapped B. bacteriovorus to an immobilized E. coli. Upon attachment, we used optical tweezers to pull the two bacteria apart. The optical tweezers provided a way to measure the attachment force of the B. bacteriovorus associated with short attachment times ranging from 90 seconds to five minutes. For the short attachment times, we found the force to be a minimum of a few piconewtons. We hypothesize that the force will become greater over longer periods of time.