This TraJ protein then acts as a molecular switch by creating a new promoter that initiates transcription of the 26 genes needed to transfer the R100 into another bacterium. We are currently studying several factors that activate these upstream promoters. We are constructing an entirely in vitro system to define the regulation precisely. Molecular epidemiology of hospital infections analyzes bacterial DNA with modern molecular biological techniques to determine the genetic relatedness of bacteria that infect patients. Helicobacter pylori is found in most cases of stomach ulcers.
Presently data indicate that it is the causative agent for many ulcers.
The technique of using short arbitrary primers and PCR reveals that the DNA of this strain varies with unusually high frequency. In a joint study, we are using this method to track infectious strains in patients and to identify the segments of DNA that are variable. We hope to discover the reason for the high variability.