Programme
and ExhibitorsSymposium 1997: Abstracts
Light-Based Detection of Pathogenic Bacteria
in vivo in Infected Hosts:
A Novel Assay system with Industrial Potential
A.A. Szalay, Ph.D.
Center for Molecular Biology & Gene Therapy, School of Medicine, Loma Linda
University, 11085 Campus Street, 142 Mortensen Hall, Loma Linda CA 92354,
909/478-8777; 909/478-4177, aSzalay@ccmail.llu.edu
The cloning and expression studies of genes and cDNAs which encode light emitting
proteins in bioluminescent organisms have provided the molecular biologists
with unique and sensitive markers. The gene constructs, when linked to appropriate
promoters, can be expressed in transformed cells, tissues, and transgenic
organisms. With the aid of a sensitive camera connected to a microscope, even
individual cells can be localized in vivo based on light emission. This light
based marker system allows the dissection of host-pathogen interaction processes
in infected host cells in real time. The principles of these experiments using
bacterial luciferases will be shown first. Secondly, detailed studies of virulence
gene activation using GFP as marker in Listeria monocytogenesduring host cell
invasion will be presented. Visualization of the subcellular localization
of bacterial cells inside mammalian cells will be documented and the possibility
of assay systems in cell cultures and whole animals to study the effect of
inhibitory compounds discussed. Further, the utilization of attenuated Listeria
strains as vectors for the delivery of DNA encoding therapeutic proteins into
the host cell cytosol will be presented.