Oxidative Stress in Bacteria

Touati D. 2000. Iron and oxidative stress in bacteria. Arch Biochem Biophys 373 1-6. 

Although the harmful effects of free radicals in biological systems were discovered about half a century ago, the importance of free radicals and antioxidants, and the therapeutic potential of the latter in health and disease, has only become clear in recent years [7], Usually, low or moderate concentrations of ROS and RNS form part of the development process of cellular structures and the host cellular defense mechanisms such as the phagocytic destruction of bacteria [2,7]. Normally, there is a balance between the formation and removal of these free radicals. However, when this balance is shifted towards overproduction of free radicals or the removal of free radicals is diminished as a result of a shortage of antioxidants, oxidative stress develops. Because these free radicals have an affinity for nucleic acids, proteins and lipids, they play a pivotal role under conditions of oxidative stress in the development of a number of chronic and degenerative diseases (see Figure 11.2) [9,7], Recently, it has been claimed that oxidative stress in saliva may play an important role in the onset of periodontal diseases [11], Furthermore the oxidative stress in patients with periodontal disease could lead to the development of cardiovascular disease [12]. 

Chavez EP, H Liinsdorf, CA Jerez (2004) Growth of polychlorinated-biphenyl-degrading bacteria in the presence of biphenyl and chlorobiphenyls generates oxidative stress and massive accumulation of inorganic polyphosphate. Appl Environ Microbiol 70 3064-3072. 

Oxidative Stress Protection in Sulfate-Reducing Bacteria... 

Evidence for an alternative oxidative stress protection mechanism in sulfate-reducing bacteria has begun to emerge. Table 10.1 provides data on the proteins implicated in this alternative system. All but one of these proteins contain distinctive types of nonheme iron active sites. This chapter describes recent results on three of these novel proteins DcrH, Rbo, and Rbr, all from Desulfovibrio vulgaris HUdenborough. 

Table 10.1. Proteins implicated in an alternative oxidative stress protection system in snlfate-reducing bacteria.

The early work on catalase expression was carried out largely in E. coli and revealed two main response mechanisms. One or the other or both responses have been identified in most other bacteria expressing a catalase. The expected and most obvious response is to oxidative stress. Addition of hydrogen peroxide directly or of ascorbate, which... 

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