Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

E. coli bacteria's defense secret revealed

14.06.2017

By tagging a cell's proteins with fluorescent beacons, Cornell researchers have found out how E. coli bacteria defend themselves against antibiotics and other poisons. Probably not good news for the bacteria.

When undesirable molecules show up, the bacterial cell opens a tunnel though its cell wall and "effluxes," or pumps out, the intruders.


In the periplasm -- the space between the inner and outer membranes of a bacteria's cell wall -- defensive proteins that detect a poison assemble like barrel staves to form a tunnel between pumps in the cell's inner and outer membranes to eject the intruders. Artist's conception by Ace George Santiago.

Credit: Ace George Santiago, Cornell University

"Dynamic assembly of these tunnels has long been hypothesized," said Peng Chen, professor of chemistry and chemical biology. "Now we see them."

The findings could lead to ways to combat antibiotic-resistant bacteria with a "cocktail" of drugs, he suggests: "One is to inhibit the assembly of the tunnel, the next is to kill the bacteria."

To study bacteria's defensive process, Chen and colleagues at Cornell selected a strain of E. coli known to pump out copper atoms that would otherwise poison the bacteria. The researchers genetically engineered it, adding to the DNA that codes for a defensive protein an additional DNA sequence that codes for a fluorescent molecule.

Under a powerful microscope, they exposed a bacterial cell to an environment containing copper atoms and periodically zapped the cell with an infrared laser to induce fluorescence. Following the blinking lights, they had a "movie" showing where the tagged protein traveled in the cell. They further genetically engineered the various proteins to turn their metal-binding capability on and off, and observed the effects.

Their research was reported in the Early Online edition of the Proceedings of the National Academy of Sciences the week of June 12. The Cornell researchers also collaborated with scientists at the University of Houston, the University of Arizona and the University of California, Los Angeles.

The key protein, known as CusB, resides in the periplasm, the space between the inner and outer membranes that make up the bacteria's cell wall. When CusB binds to an intruder - in this experiment, a copper atom - that has passed through the porous outer membrane, it changes its shape so that it will attach itself between two related proteins in the inner and outer membranes to form a complex known as CusCBA that acts as a tunnel through the cell wall. The inner protein has a mechanism to grab the intruder and push it through.

The tunnel locks the inner and outer membranes together, making the periplasm less flexible and interfering with its normal functions. The ability to assemble the tunnel only when needed, rather than having it permanently in place, gives the cell an advantage, the researchers point out.

This mechanism for defending against toxic metals may also explain how bacteria develop resistance to antibiotics, by mutating their defensive proteins to recognize them. Similar mechanisms may be found in other species of bacteria, the researchers suggested.

###

The work was supported by the Army Research Office and the National Institutes of Health.

Media Contact

Daryl Lovell
dal296@cornell.edu
607-592-3925

 @cornell

http://pressoffice.cornell.edu 

Daryl Lovell | EurekAlert!

More articles from Life Sciences:

nachricht Making fuel out of thick air
08.12.2017 | DOE/Argonne National Laboratory

nachricht ‘Spying’ on the hidden geometry of complex networks through machine intelligence
08.12.2017 | Technische Universität Dresden

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Towards data storage at the single molecule level

The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.

Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...

Im Focus: Successful Mechanical Testing of Nanowires

With innovative experiments, researchers at the Helmholtz-Zentrums Geesthacht and the Technical University Hamburg unravel why tiny metallic structures are extremely strong

Light-weight and simultaneously strong – porous metallic nanomaterials promise interesting applications as, for instance, for future aeroplanes with enhanced...

Im Focus: Virtual Reality for Bacteria

An interdisciplinary group of researchers interfaced individual bacteria with a computer to build a hybrid bio-digital circuit - Study published in Nature Communications

Scientists at the Institute of Science and Technology Austria (IST Austria) have managed to control the behavior of individual bacteria by connecting them to a...

Im Focus: A space-time sensor for light-matter interactions

Physicists in the Laboratory for Attosecond Physics (run jointly by LMU Munich and the Max Planck Institute for Quantum Optics) have developed an attosecond electron microscope that allows them to visualize the dispersion of light in time and space, and observe the motions of electrons in atoms.

The most basic of all physical interactions in nature is that between light and matter. This interaction takes place in attosecond times (i.e. billionths of a...

Im Focus: A transistor of graphene nanoribbons

Transistors based on carbon nanostructures: what sounds like a futuristic dream could be reality in just a few years' time. An international research team working with Empa has now succeeded in producing nanotransistors from graphene ribbons that are only a few atoms wide, as reported in the current issue of the trade journal "Nature Communications."

Graphene ribbons that are only a few atoms wide, so-called graphene nanoribbons, have special electrical properties that make them promising candidates for the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

Blockchain is becoming more important in the energy market

05.12.2017 | Event News

 
Latest News

Making fuel out of thick air

08.12.2017 | Life Sciences

Rules for superconductivity mirrored in 'excitonic insulator'

08.12.2017 | Information Technology

Smartphone case offers blood glucose monitoring on the go

08.12.2017 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>