Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Bacteria, beware: New finding about E coli could block infections, lead to better treatments

27.06.2006
A newly discovered receptor in a strain of Escherichia coli can be blocked to avert infection, a finding that might aid in developing better therapies to treat bacterial infections resulting in food poisoning, diarrhea or plague.

Researchers at UT Southwestern Medical Center are the first to identify the receptor, known as QseC, used by a diarrhea-causing strain of E coli to receive signals from human flora and hormones in the intestine and express virulence genes to initiate infection.

In a study made available online this week and in an upcoming issue of the Proceedings of the National Academy of Sciences, researchers describe how they used phentolamine, an alpha blocker drug used to treat hypertension, to successfully impede signaling to the receptor. Without such signals, bacteria then pass blindly through the digestive tract without infecting cells.

"This receptor is found in many pathogens, so we can use this knowledge to design specific antagonists to block bacterial infections," said Dr. Vanessa Sperandio, senior author of the study and assistant professor of microbiology at UT Southwestern.

Prior research by Dr. Sperandio found that when a person ingests the more virulent enterohemorrhagic E coli, or EHEC – which is usually transmitted through contaminated food such as raw meat – it travels peacefully through the digestive tract until reaching the intestine. There, however, chemicals produced by the friendly gastrointestinal microbial flora and the human hormones epinephrine and norepinephrine alert the bacteria to its location.

This cellular cross talk triggers a cascade of genetic activations prompting EHEC to colonize and translocate toxins into cells, altering the makeup of the cells and robbing the body of nutrients. An infected person may develop bloody diarrhea or even hemolytic uremic syndrome, which can cause death in immune-weakened people, the elderly and young children.

The new study identifies QseC as the specific receptor by which EHEC senses the signals. When the receptor binds to signaling molecules, the bacterium can infect cells.

Researchers tested the capacity of adrenergic antagonists, drugs such as alpha and beta blockers, to disrupt the receptor's sensing ability. They found that phentolamine binds to the QseC receptor and occupies the pocket that the receptor would use to recognize the host epinephrine and norepinephrine signals – thus blocking the QseC receptor from sensing the signals and preventing it from being able to express its virulence genes in cells.

This knowledge opens the door to further understanding of the signaling processes between microbes and humans and to the development of novel treatments of bacterial infections with antagonists to these signals, Dr. Sperandio said.

New therapies are important because treating some bacterial infections with conventional antibiotics can cause the release of more toxins and may worsen disease outcome.

That importance is magnified because of the QseC receptor's existence in other types of bacteria, including, Shigella, which causes dysentery; Salmonella, which causes food poisoning and gastroenteritis; and Yersinia, which causes bubonic plague. Those are all emerging infectious diseases that afflict thousands of people each year in the United States and worldwide, according to the Centers for Disease Control and Prevention.

"Overuse of antibiotics has led bacteria to develop resistance to antibiotics, so a novel type of therapy is needed," Dr. Sperandio said.

Cliff Despres | EurekAlert!
Further information:
http://www.utsouthwestern.edu

More articles from Life Sciences:

nachricht Rainbow colors reveal cell history: Uncovering β-cell heterogeneity
22.09.2017 | DFG-Forschungszentrum für Regenerative Therapien TU Dresden

nachricht The pyrenoid is a carbon-fixing liquid droplet
22.09.2017 | Max-Planck-Institut für Biochemie

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: The pyrenoid is a carbon-fixing liquid droplet

Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.

A warming planet

Im Focus: Highly precise wiring in the Cerebral Cortex

Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.

The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...

Im Focus: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

Im Focus: Ultrafast snapshots of relaxing electrons in solids

Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!

When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...

Im Focus: Quantum Sensors Decipher Magnetic Ordering in a New Semiconducting Material

For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.

Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

Rainbow colors reveal cell history: Uncovering β-cell heterogeneity

22.09.2017 | Life Sciences

Penn first in world to treat patient with new radiation technology

22.09.2017 | Medical Engineering

Calculating quietness

22.09.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>