Bacteria, molecular targets

In medicine, we do a similar thing if we want to control microbial diseases. To overcome or to prevent resistance of bacteria toward a particular antibiotic, very often mixtures of structurally different antibiotics are applied, whose molecular targets often differ. If only one antibiotic were given to all patients, the development of resistance would be much favored. 

Myxobacteria present one of the richest sources of structurally novel types of natural products and an impressive number of architecturally unique and biosynthetically diverse metabolites have been isolated from these gliding bacteria/ Many of these metabolites exhibit important biological properties, including antibiotic, antifungal, antiviral, or antiproliferative activities. In many cases, molecular targets are specifically addressed, ranging from the cytoskeleton, nucleic acid polymerases, the respiratory chain, nuclear transport, microfilaments, and protein or fatty acid synthesis. 

Figure 1 Molecular targets in bacteria that can be affected by natural products.

Lanemo Myhrinder, A., Hellqvist, E., Sidorova, E., Soderbeig, A., Baxendale, H., Dahle, C., Willander, K., Tobin, G., Backman, E., Soderberg, O., Rosenquist, R., Horitko, S., and Rosen, A. (2008). A new perspective molecular motifs on oxidized LDL, apoptotic cells, and bacteria are targets for chronic lymphocytic leukemia antibodies. Blood 111, 3838-3848. 

In bacteria (Escherichia coli), paraquat is concentrated, reduced to the monocation radical, and combines with molecular oxygen to produce the superoxide radical within the cell. Copper and iron are essential mediators in bactericidal effects. The cytoplasmic membrane is the target organelle in paraquat toxicity to E. coli, and extent of damage correlates positively with levels of these metals (Kohen and Chevion 1988). 

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