X-rays reveal the self-defence mechanisms of bacteria

Sep 14, 2012
The toxins normally bind very strongly to the antitoxins and are thus not only inactive, but also prevent the production of more toxin from the information encoded in the bacterial DNA. During the dormant state, however, the antitoxins are degraded, and the toxins released (step 1). The free toxins now bind to unoccupied antitoxins on DNA within the area encoding the toxin-antitoxin couple (step 2). Binding increasing amounts of toxin eventually leads to the release of the molecules from the gene (steps 3 and 4) and finally to new toxin production. Credit: Ditlev E. Brodersen

A research group at Aarhus University has gained unique insight into how bacteria control the amount of toxin in their cells. The new findings can eventually lead to the development of novel forms of treatment for bacterial infections.

Many pathogenic bacteria are able to go into a dormant state by producing persister cells that are not susceptible to conventional antibiotics. This causes serious problems in the treatment of life-threatening diseases such as tuberculosis, where the presence of persister cells often leads to a resurgence of infection following .

At the molecular level, the formation of persister cells is due to the presence of toxins that are produced by the bacteria themselves, and which enable them to enter the dormant state. During this hibernation period, the bacteria constantly regulate the amount of toxin at exactly the same level and thus maintain the dormant state.

In an article recently published in the American scientific journal Structure, the researchers at the Department of and Genetics, Aarhus University, present new results that reveal the molecular details of the of toxins.

By isolating and crystallising the toxin molecules and their molecular companions – the antitoxins – and by subsequently exposing the crystals to strong X-rays, the research team (consisting of the two PhD students Andreas Bøggild and Nicholas Sofos and Associate Professor Ditlev E. Brodersen) gained unique insight into how bacteria control the amount of toxin in the cell (illustrated in the info box).

The new findings can eventually lead to the development of entirely new forms of treatment of bacterial infections that work initially by blocking function and production, and subsequently by using traditional antibiotics to fight the .

Explore further: Some anti-inflammatory drugs affect more than their targets

More information: www.sciencedirect.com/science/… ii/S0969212612002997

add to favorites email to friend print save as pdf

Related Stories

Fighting bacteria's strength in numbers

May 17, 2012

Scientists at The University of Nottingham have opened the way for more accurate research into new ways to fight dangerous bacterial infections by proving a long-held theory about how bacteria communicate ...

Bacteria poison themselves from within

Mar 23, 2011

(PhysOrg.com) -- The research group led by Anton Meinhart at the Max Planck Institute for Medical Research in Heidelberg has shown that proteins from the zeta toxin group trigger a self-destructive mechanism ...

Turning bacteria against themselves

Feb 08, 2011

Bacteria often attack with toxins designed to hijack or even kill host cells. To avoid self-destruction, bacteria have ways of protecting themselves from their own toxins.

Recommended for you

Some anti-inflammatory drugs affect more than their targets

33 minutes ago

Researchers have discovered that three commonly used nonsteroidal anti-inflammatory drugs, or NSAIDs, alter the activity of enzymes within cell membranes. Their finding suggests that, if taken at higher-than-approved ...

Researchers discover new strategy germs use to invade cells

Aug 20, 2014

The hospital germ Pseudomonas aeruginosa wraps itself into the membrane of human cells: A team led by Dr. Thorsten Eierhoff and Junior Professor Dr. Winfried Römer from the Institute of Biology II, members of the Cluster ...

Progress in the fight against harmful fungi

Aug 20, 2014

A group of researchers at the Max F. Perutz Laboratories has created one of the three world's largest gene libraries for the Candida glabrata yeast, which is harmful to humans. Molecular analysis of the Candida ...

How steroid hormones enable plants to grow

Aug 19, 2014

Plants can adapt extremely quickly to changes in their environment. Hormones, chemical messengers that are activated in direct response to light and temperature stimuli help them achieve this. Plant steroid ...

Surviving the attack of killer microbes

Aug 19, 2014

The ability to find food and avoid predation dictates whether most organisms live to spread their genes to the next generation or die trying. But for some species of microbe, a unique virus changes the rules ...

Histones and the mystery of cell proliferation

Aug 19, 2014

Before cells divide, they create so much genetic material that it must be wound onto spools before the two new cells can split apart. These spools are actually proteins called histones, and they must multiply ...

User comments : 0