The role of microbial metal resistance and detoxification mechanisms in environmental bioassay research

Abstract

Numerous biological methods and bioassays have been developed for assessing toxicants in both environmental and laboratory samples. In many bioassays, microorganisms are used because of their rapid growth rates and ubiquitous distribution in aquatic and terrestrial environments. However, information is often lacking on the ecology, physiology and genetics of the test organism(s) or other organisms present in the test system. For example, Hg 2 + can be volatilized via the mercuric reductase enzyme found in certain bacterial strains. Moreover, this detoxification/resistance mechanism may occur while the environmental sample is being used in a bioassay protocol. A fundamental knowledge of the mechanism(s) involved in microbial detoxification/resistance mechanisms is essential to understand how the bioassay organism(s) and toxicant(s) behave in environmental samples tested with bioassay protocols. This manuscript will review selected metal (arsenic, cadmium, mercury) detoxification/resistance mechanisms in bacteria with an emphasis on the manner in which the mechanisms may influence the bioassay results.

Impacts of copper and lead exposure on prokaryotic communities from contaminated contrasted coastal seawaters: the influence of previous metal exposure

“…Moreover, it did not prove to have a synergistic interaction with Cu. The weak toxicity of Pb on prokaryotic communities could be explained by its resistance and detoxification mechanisms, which are very efficient in microbial organisms (Trevors, 1989;Nies, 1999;Nayar et al, 2004;Naik and Dubey, 2013).…”