How Microbes Take Out the Trash

Graduate student and study lead author Eun-Hae Kim checks on a flask
containing bacteria growing in a liquid medium. (Photo by Beatriz
Verdugo/UANews)
Graduate student and study lead author Eun-Hae Kim checks on a flask containing bacteria growing in a liquid medium. (Photo by Beatriz Verdugo/UANews)

Microbes have colonized virtually every spot on this planet, from deep sea vents spewing scalding seawater laden with heavy metals to the icy pinnacles of the world's tallest mountain ranges.

Part of their ability to thrive in the harshest of environments rests on sophisticated cellular mechanisms to deal with substances that are needed to run biochemical processes but dangerous when allowed to accumulate to higher levels.

"Copper is a double-edged sword for organisms because it is a vital ingredient in certain enzymes needed to carry out metabolic functions, but too much of it is toxic and can kill the cell," said Christopher Rensing, an associate professor in the department of soil, water and environmental science in the University of Arizona's College of Agriculture and Life Sciences.

This delicate balance is maintained by specialized transporter proteins embedded in the cell membranes that act as trash men, collecting toxins such as metal ions and pumping them out of the cell.

Research in Rensing's lab focuses on how microbes deal with metals such as copper and silver and discovering new ways to use metals to fight germs.

Scientists have long been fascinated with the intricacy of transporter proteins and their keen ability to recognize chemicals and take the appropriate action. However, many of the precise mechanisms remain elusive.

Studying a class of cellular transporters known as RND proteins in great detail, a team led by UA scientists Eun-Hae Kim, Megan McEvoy and Christopher Rensing has gained new insights into the way they function. Based on the findings, published in the current issue of the Journal of Bacteriology and chosen for a spotlight feature by the journal editors, Kim and her team propose a revised working model for those transporters that has implications for antimicrobial drug development.

Read more from this article that appeared in the May 9 issue of UANews at the link below.  

Date released: 
May 11 2011
Contact: 
Christopher Rensing