Bacteria that colonize sites polluted by industrial waste are capable of metabolizing synthetic and recalcitrant chemicals that have been in the biosphere for only a few years.
This capability is orchestrated by the integration of environmental and physiological signals into regulatory systems that tightly control the expression of genes that are in charge of degrading such molecules. The emergence of these capabilities is due not only to the adaptation of catabolic enzymes acting on new substrates, but also to the emergence of new regulators that firmly control the expression of the genes involved in the production of catabolic enzymes. To answer this question, we have examined the oxidative stress brought about by the still-evolving 2,4-dinitrotoluene biodegradative pathway in Burkholderia sp. DNT. The dnt pathway of this bacterium apparently evolved from a precursor naphthalene degradation route and the first enzyme (2,4-dinitrotoluene dioxygenase) maintains some activity towards its earlier substrate. Examination of both in vivo reactions and the associated regulatory system suggests that ROS production is the first bottleneck that evolving pathways have to overcome for dealing with novel compounds. Evolutionary consequences -and some hints for engineering new biocatalysts- will be discussed.
SEMINAR’S DATE, TIME AND PLACE: Wednesday, February 14, 2018. Assembly Hall.
SPEAKER: Víctor de Lorenzo
