Lars H. Hansen

Section of Microbiology, University of Copenhagen, Denmark
Brief Biography: 

Current research
My research is focused on taking a molecular approach to answer complex questions in microbial ecology. Main fields of research include the use of bacterial whole-cell biosensors to show how bacteria perceive different compounds in their environment. Biosensors are bacteria engineered to produce a measurable gene product (light from lux genes, fluorescence form gfp or enzyme activity from the lacZ gene) in the presence or absence of certain compounds. I am involved in detecting the presence (and bioavailable concentrations) of heavy metals or genotoxic compounds but also compounds involved in bacterial communication (e.g. signaling) or inter-bacterial warfare compounds such as antibiotics. We have employed these bacterial whole-cell biosensors in complex environments such as soil and animal models.

Another field of interest is focused on bacterial resistance to antibiotics, especially the so-called multidrug efflux pumps from Gram-negative bacteria. These pumps can rid the bacterial host cell of a variety of compounds. We are investigating the change in specificity of such a pump in response to changing environmental conditions.

Finally, I find the bacterial maintenance and interchange (transfer) of plasmid DNA very interesting. We are currently working with new methods for estimating plasmid stability.