Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Advance in cholera bacteria points to new treatment and vaccine

09.12.2005


Opening a new door to an effective vaccine and therapy for a disease that strikes thousands annually, researchers at Dartmouth Medical School discovered that the bacteria that causes the intestinal disease Cholera spreads in the environment in much the same way it infects humans. Appearing in the December 8 issue of the journal Nature, the study investigates the bacterium Vibrio cholerae and its ability to attach to a host, enabling it to multiply and adding to the risk of infecting humans.



"We’ve discovered, through genetics, a factor that is important in the normal biology of the organism out in the environment and it is also one of the very initial factors for cholera colonization in the intestine," said Dr. Ronald Taylor, professor of microbiology and immunology at DMS who led the research. "Now that we know what the bacterium attaches to in the intestine, we can find ways to block that initial contact."

Cholera and the bacterium that causes it is found in contaminated drinking water and food, often in underdeveloped countries and refugee camps. Once the disease takes hold, it causes diarrhea, vomiting, severe dehydration and can result in death if treatment is not promptly given. In 2001 alone, 28 countries reported over 40 outbreaks of cholera to the World Health Organization, resulting in the deaths of thousands.


Large outbreaks are often traced back to contaminated water supplies that are commonly associated with algal or zooplankton blooms. For the V. cholerae bacterium to infect someone with cholera, the bacterium often binds to plankton in the aquatic environment before it arrives at the human intestine via contaminated food and water sources. V. cholerae attaches to the outer surface of plankton, made up of a carbonate substance called chitin. Once attached to the plankton’s chitin, the bacterium thrives on the carbon and multiplies. Humans do not have chitin in the surface of intestinal cells, where the bacterium takes hold, and researchers have been searching for another substance that could be responsible for playing a role in attachment.

In the study, Taylor and colleagues screened cultured intestinal cells and found mutant bacteria that had trouble binding to the intestinal cells. One mutant strain of V. cholerae lacks a gene that enables it to properly bind with a sugar called GlcNAc. When they compared it with normal, wild-type V. cholerae bacteria, the researchers found that the protein encoded by this gene provided normal bacteria the ability to attach to the GlcNAc on cells. The team verified that the GlcNAc in the intestine initiates the attachment and colonization of the bacteria by testing the mutant strain on zooplankton and cultured intestinal cells in vitro as well as in an in vivo cholera model.

"We set out to find factors that would reduce the bacteria’s ability to bind to the epithelial lining of the intestine," said Taylor. "What’s interesting is that we’ve identified a factor that works both in the environment and in the human body. This type of link hasn’t been discussed before and it has a strong potential for vaccine and therapeutic development."

These findings could lead to a new form of therapy to treat people with cholera. "Now that we know that the bacteria are binding this particular sugar, we could essentially trick the infecting bacteria to bind to the sugar included in a derivative of oral rehydration therapy solution instead of the intestine," said study co-author Brooke Jude, a fourth-year PhD student at Dartmouth Medical School.

A vaccine for cholera already exists, but only works 50% of the time and people who take it are only immune for 12 months, according to Taylor. Taylor believes that a more effective vaccine could be developed by inducing the production of antibodies directed against the protein his research team has discovered, thereby blocking its function. This would inhibit an early step in the intestinal colonization process, and the bacteria would pass harmlessly through the body. The authors acknowledge that in addition to GlcNAc, there may be other points of attachment that could still be responsible for allowing the bacteria to bind to the intestine, and they are currently focusing their research to identify any other areas of attachment..

"There may be more of these factors and as we find them and knock them out, we’ll decrease the ability for cholera bacteria to colonize even further," said Taylor.

Andrew Nordhoff | EurekAlert!
Further information:
http://www.dartmouth.edu

More articles from Health and Medicine:

nachricht Researchers identify new way to unmask melanoma cells to the immune system
17.01.2018 | Duke University Medical Center

nachricht Study advances gene therapy for glaucoma
17.01.2018 | University of Wisconsin-Madison

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

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

Im Focus: Scientists decipher key principle behind reaction of metalloenzymes

So-called pre-distorted states accelerate photochemical reactions too

What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...

Im Focus: The first precise measurement of a single molecule's effective charge

For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.

Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...

Im Focus: Paradigm shift in Paris: Encouraging an holistic view of laser machining

At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.

No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...

Im Focus: Room-temperature multiferroic thin films and their properties

Scientists at Tokyo Institute of Technology (Tokyo Tech) and Tohoku University have developed high-quality GFO epitaxial films and systematically investigated their ferroelectric and ferromagnetic properties. They also demonstrated the room-temperature magnetocapacitance effects of these GFO thin films.

Multiferroic materials show magnetically driven ferroelectricity. They are attracting increasing attention because of their fascinating properties such as...

Im Focus: A thermometer for the oceans

Measurement of noble gases in Antarctic ice cores

The oceans are the largest global heat reservoir. As a result of man-made global warming, the temperature in the global climate system increases; around 90% of...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

10th International Symposium: “Advanced Battery Power – Kraftwerk Batterie” Münster, 10-11 April 2018

08.01.2018 | Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

 
Latest News

Polymers Based on Boron?

18.01.2018 | Life Sciences

Bioengineered soft microfibers improve T-cell production

18.01.2018 | Life Sciences

World’s oldest known oxygen oasis discovered

18.01.2018 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>