Subscribe free to our newsletters via your
. Space Travel News .




EPIDEMICS
50-year cholera mystery solved
by Staff Writers
Austin TX (SPX) Jun 07, 2012


File image courtesy AFP.

For 50 years scientists have been unsure how the bacteria that gives humans cholera manages to resist one of our basic innate immune responses. That mystery has now been solved, thanks to research from biologists at The University of Texas at Austin.

The answers may help clear the way for a new class of antibiotics that don't directly shut down pathogenic bacteria such as V. cholerae, but instead disable their defenses so that our own immune systems can do the killing.

Every year cholera afflicts millions of people and kills hundreds of thousands, predominantly in the developing world. The infection causes profuse diarrhea and vomiting. Death comes from severe dehydration.

"If you understand the mechanism, the bacterial target, you're more likely to be able to design an effective antibiotic," says Stephen Trent, associate professor of molecular genetics and microbiology and lead researcher on the study.

The bacterium's defense, which was unmasked this month in the Proceedings of the National Academy of Sciences, involves attaching one or two small amino acids to the large molecules, known as endotoxins, that cover about 75 percent of the bacterium's outer surface.

"It's like it's hardening its armor so that our defenses can't get through," says Trent.

Trent says these tiny amino acids simply change the electrical charge on that outer surface of the bacteria. It goes from negative to neutral.

That's important because the molecules we rely on to fight off such bacteria, which are called cationic antimicrobial peptides (CAMPs), are positively charged. They can bind to the negatively charged surface of bacteria, and when they do so, they insert themselves into the bacterial membrane and form a pore. Water then flows through the pore into the bacterium and pops it open from the inside, killing the harmful bacteria.

It's an effective defense, which is why these CAMPs are ubiquitous in nature (as well as one of the main ingredients in over-the-counter antibacterial ointments such as Neosporin).

However, when the positively charged CAMPs come up against the neutral V. cholerae bacteria, they can't bind. They bounce away, and we're left vulnerable.

V. cholerae can then invade our intestines and turn them into a kind of factory for producing more cholera, in the process rendering us incapable of holding onto fluids or extracting sufficient nutrients from what we eat and drink.

"It pretty much takes over your normal flora," says Trent.

Trent says that scientists have known for some time that the strain of V. cholerae responsible for the current pandemic in Haiti and elsewhere is resistant to these CAMPs. It's that resistance that is likely responsible, in part, for why the current strain displaced the strain that was responsible for previous pandemics.

"It's orders of magnitude more resistant," says Trent.

Now that Trent and his colleagues understand the mechanism behind this resistance, they hope to use that knowledge to help develop antibiotics that can disable the defense, perhaps by preventing the cholera bacteria from hardening their armor. If that happened, our CAMPs could do the rest of the work.

Trent says the benefits of such an antibiotic would be considerable. It might be effective against not just cholera but a range of dangerous bacteria that use similar defenses. And because it disarms but doesn't kill the bacteria outright, as traditional antibiotics do, it might take longer for the bacteria to mutate and evolve resistance in response to it.

"If we can go directly at these amino acids that it uses to protect against us, and then allow our own innate immune system to kill the bug, there could be less selection pressure," he says.

Trent's lab is now screening for compounds that would do precisely that.

.


Related Links
University of Texas at Austin
Epidemics on Earth - Bird Flu, HIV/AIDS, Ebola






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News





EPIDEMICS
China faces 'serious' epidemic of drug-resistant TB
Washington (AFP) June 6, 2012
China faces a "serious epidemic" of drug-resistant tuberculosis according to the first-ever nationwide estimate of the size of the problem there, said a US-published study on Wednesday. "In 2007, one third of the patients with new cases of tuberculosis and one half of the patients with previously treated tuberculosis had drug-resistant disease," said the study in the New England Journal of M ... read more


EPIDEMICS
Another Ariane 5 begins its initial build-up at the Spaceport

Boeing Receives DARPA Airborne Satellite Launch Study Contract

Sea Launch Delivers the Intelsat 19 Spacecraft into Orbit

SpaceX Dragon capsule splash lands in Pacific

EPIDEMICS
Wind may have driven avalanches on Martian dunes

On The Hunt For Light-Toned Veins Of Gypsum

Mars missions may learn from meteor Down Under

Waking Up with the Sun's Rays

EPIDEMICS
UA Lunar-Mining Team Wins National Contest

NASA Lunar Spacecraft Complete Prime Mission Ahead of Schedule

NASA Offers Guidelines To Protect Historic Sites On The Moon

Neil Armstrong gives rare interview - to accountant

EPIDEMICS
It's a Sim: Out in Deep Space, New Horizons Practices the 2015 Pluto Encounter

Beyond Pluto And Exploring the Kuiper Belt

Uranus auroras glimpsed from Earth

Herschel images extrasolar analogue of the Kuiper Belt

EPIDEMICS
Tiny Planet-Finding Mirrors Borrow from Webb Telescope Playbook

Astronomers Probe 'Evaporating' Planet Around Nearby Star with Hobby-Eberly Telescope

Venus transit may boost hunt for other worlds

NSO To Use Venus Transit To Fine-Tune Search For Other Worlds

EPIDEMICS
NASA Begins Development of Space Launch System Flight Software

Dream Chaser Flight Vehicle Scales Rocky Mountain Summits

Boeing Delivers First Space Launch System Hardware to NASA

Sierra Nevada Announces the Completion of Four Dream Chaser Milestones FOR NASA

EPIDEMICS
What will China's Taikonauts do aboard Tiangong 1?

Why is China sending a woman into space?

China launches telecommunication satellite

Tiangong 1 Ready To Meet Shenzhou 9

EPIDEMICS
Dawn Mission Video Shows Vesta's Coat of Many Colors

Dawn deep in the asteroid belt orbiting Vesta

UT's Josh Emery Uncovers Clues About Asteroid That Will Pass Near Earth

Rosetta flyby uncovers the complex history of asteroid Lutetia




The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement