Novel bacterial 'language' discovered

Jul 15, 2013
The micrograph shows the bacterium Photorhabdus luminescens. The cells labeled in red produce the aggregation factor. Credit: Ralf Heermann, LMU

(Phys.org) —LMU researchers have identified a yet unknown bacterial cell-cell communication system.

In nature, bacteria are no mavericks but live in close association with neighboring bacteria. They have evolved specific cell- systems that allow them to detect the presence of others and even to build up cooperative networks.

LMU microbiologist PD Dr. Ralf Heermann and Professor Helge Bode of the Goethe-University in Frankfurt have just reported the discovery of a previously unknown bacterial "language". Their findings are detailed in the latest issue of the journal Nature Chemical Biology. "Our results demonstrate that bacterial communication is much more complex than has been assumed to date," Heermann says.

The bacterial that is currently best understood uses N-acylhomoserine lactones (AHLs) as signals. These compounds are made by enzymes that belong to the group of LuxI-family synthases. Transmitting cells secrete the signal and neighboring cells recognize the concentration via a LuxR-type receptor. Signal perception changes the pattern of in the receiving cells, which results in alterations in their functional properties or behavior. However, many bacteria have LuxR receptors but lack any LuxI homolog, so that they cannot produce AHLs. These receptors are referred to as LuxR solos.

A new class of bacterial signaling molecules

Ralf Heermann and Helge Bode have now discovered a type of ligand that binds to LuxR solos. As , they chose the species Photorhabdus luminescens, a that is lethal to insects.

Novel bacterial 'language' discovered
Bacteria communicate by means of chemical processes. LMU microbiologist PD Dr. Ralf Heermann and Professor Helge Bode of the Goethe-University Frankfurt have identified a novel bacterial cell-cell communication system that uses alpha-pyrones as signals. The pyrones are produced by the synthase enzyme PpyS and received by the LuxR solo receptor PluR.

"We have identified a new class of bacterial signaling molecules, which are produced by a previously unknown biochemical route," explains Helge Bode, Merck Professor of Molecular Biotechnology at Goethe-Universität Frankfurt. It turns out that a LuxR solo of this bacterium responds to compounds called alpha-pyrones, specifically to photopyrones. Furthermore, the researchers have identified the pyrone synthase (PpyS) that catalyzes the biosynthesis of photopyrones. The pyrone-based signaling system allows the bacteria to recognize one another, whereupon they produce a surface factor that causes cell clumping. Heermann and Bode assume that this collective behavior makes the cells less vulnerable to the insect's innate immune system, and then allows them to kill their victims by the production of various of toxins." P. luminescens is a useful model organism, because it is related to many human pathogens, including coliform bacteria such as enterohemorrhagic E. coli (EHEC) and well as plague bacteria," Heermann points out.

The new findings are also of more general interest because communication systems of bacterial pathogens offer promising targets for antimicrobial drugs. Thus, agents that interfere with bacterial "small talk" could inhibit the production of toxins or prevent the formation of biofilms. Since those drugs would only prevent the expression of pathogenic traits, rather than killing bacteria as antibiotics do, the danger of drug resistances would be enormously diminished.

Explore further: Chemical biologists find new halogenation enzyme

More information: dx.doi.org/10.1038/nchembio.1295

Related Stories

Bacteria communicate to help each other resist antibiotics

Jul 03, 2013

New research from Western University unravels a novel means of communication that allows bacteria such as Burkholderia cenocepacia (B. cenocepacia) to resist antibiotic treatment. B. cenocepacia is an environmental bacter ...

Recommended for you

Chemical biologists find new halogenation enzyme

14 hours ago

Molecules containing carbon-halogen bonds are produced naturally across all kingdoms of life and constitute a large family of natural products with a broad range of biological activities. The presence of halogen substituents ...

Protein secrets of Ebola virus

20 hours ago

The current Ebola virus outbreak in West Africa, which has claimed more than 2000 lives, has highlighted the need for a deeper understanding of the molecular biology of the virus that could be critical in ...

Protein courtship revealed through chemist's lens

20 hours ago

Staying clear of diseases requires that the proteins in our cells cooperate with one another. But, it has been a well-guarded secret how tens of thousands of different proteins find the correct dancing partners ...

Decoding 'sweet codes' that determine protein fates

22 hours ago

We often experience difficulties in identifying the accurate shape of dynamic and fluctuating objects. This is especially the case in the nanoscale world of biomolecules. The research group lead by Professor Koichi Kato of ...

Conjecture on the lateral growth of Type I collagen fibrils

Sep 12, 2014

Whatever the origin and condition of extraction of type I collagen fibrils, in vitro as well as in vivo, the radii of their circular circular cross sections stay distributed in a range going from 50 to 100 nm for the most ...

User comments : 2

Adjust slider to filter visible comments by rank

Display comments: newest first

JVK
1 / 5 (3) Jul 15, 2013
The added systems complexity reported here simply suggests that we've had much more to learn about quorum-sensing than most people realized. The journalistic inference, however, defies the logic of what IS known about Nutrient-dependent / pheromone-controlled adaptive evolution in species from microbes to man. See for example: http://figshare.c...n/155672 It seems likely that we could use the species-specific pheromones to control infections, whether or not we learn more about ALL the molecular mechanisms that enable pheromone-controlled reproduction. Isn't Bonnie Bassler's group already working on that?
bortlethetortle
not rated yet Jul 18, 2013
Not really that new. See the Ted Talk by Bonnie Bassler on How bacteria communicate, from a few years ago