Biology Reference
In-Depth Information
17
Determining the Cellular Targets of Reactive Oxygen
Species in
Borrelia burgdorferi
Julie A. Boylan and Frank C. Gherardini
Summary
The response of
Borrelia burgdorferi
to the challenge of reactive oxygen species (ROS)
is a direct result of its limited biosynthetic capabilities and lack of biologically significant
levels of intracellular Fe. In other bacteria, the major target for oxidative damage is DNA
as a consequence of the reaction of “free” intracellular with ROS through the Fenton
reaction. Therefore, cellular defenses in these bacteria are focused on protecting this
essential cellular component. This does not seem to be the case for
B. burgdorferi.
In this
chapter, we describe methods that were used to analyze the potential targets for ROS in
B. burgdorferi
. Surprisingly, membrane lipids (e.g., linoleic and linolenic acids) derived
from host are the major target of ROS in the Lyme disease spirochete.
Key Words:
Oxidative stress; DNA damage; lipid damage.
1. Introduction
One imposing challenge faced by organisms living in an oxygen-rich
environment is that of dealing with toxic products resulting from incomplete
reduction of oxygen. This assault primarily comes from reactions involving
endogenous metalloproteins, flavoproteins, and so on as a consequence of
exposure to or metabolism of oxygen
(1)
. Pathogenic bacteria face a similar
metabolic test but also are challenged by exogenous reactive oxygen generated
by host immune cells for the express purpose of eliminating invading microbes.
These compounds constitute a formidable challenge that must be overcome
for bacterial pathogens to successfully survive, colonize, and cause disease in
mammalian hosts.
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