Featured Research

from universities, journals, and other organizations

Mysterious workings of cholera bacteria uncovered

Date:
July 28, 2010
Source:
Rensselaer Polytechnic Institute
Summary:
Researchers have found that an enzyme in the bacteria that causes cholera uses a previously unknown mechanism in providing the bacteria with energy. Because the enzyme is not found in most other organisms, including humans, the finding offers insights into how drugs might be created to kill the bacteria without harming humans.

Researchers have found that an enzyme in the bacteria that causes cholera uses a previously unknown mechanism in providing the bacteria with energy. Because the enzyme is not found in most other organisms, including humans, the finding offers insights into how drugs might be created to kill the bacteria without harming humans.

Blanca Barquera, a Rensselaer associate professor of biology, led a team (including research professor Joel Morgan and postdoctoral fellow Oscar Juarez) whose findings were published in the June 28 edition of the Proceedings of the National Academy of Science.

The team studied Na+-NQR, an enzyme that is essentially two linked machines to create energy from food and electrically charge the cell membrane of Vibrio cholerae, powering many cellular functions.

Vibrio cholerae causes cholera, a disease transmitted primarily through contaminated drinking water. Cholera, in which severe diarrhea and vomiting lead to rapid dehydration, is a major cause of death in the developing world, and in the aftermath of catastrophes that compromise water systems.

The Rensselaer team found that the way in which the two machines are linked in Na+-NQR is different from other respiratory enzymes and likely involves much more movement of the protein than has been observed in other enzymes.

Their work stems from an interest in cellular respiration. Cellular respiration carries electrons from food to oxygen, in what amounts to a controlled burn. This process releases energy.

"Cellular respiration is remarkable," Barquera said. "It is one of the most efficient energy conversion processes known, and nevertheless, does not require high temperatures. This efficiency has drawn the attention of researchers."

In more complex organisms, like humans, the process of creating energy for a cell -- respiration -- takes place in specialized organelles within the cell called mitochondria.

But in bacteria, which lack mitochondria, respiration occurs in the cell membrane. Na+-NQR is a respiratory enzyme found on the cell membrane of Vibrio Cholerae.

The enzyme creates energy through respiration and uses that energy to pump ions out of the cell, electrically charging the cell membrane and providing power for all the functions of the cell. Unlike similar enzymes found in many animals and bacteria, Na+-NQR pumps sodium ions out of the cell, rather than protons.

Barquera's paper in PNAS describes the mechanism the enzyme uses to convert energy using sodium ions.

"Na+-NQR plays the same role as human respiratory proteins but it is much smaller," Barquera said. "We want to understand how it works, how it produces energy. If we understand how Na+-NQR works, we can learn the basic principles used by living organisms to convert energy and transport ions."

Researchers studied the enzyme by removing it from the inner cell membrane and studying it in a solution. Na+-NQR, which prefers an environment of water and oil, flourished in a solution similar to detergent, which mimics the bacterial membrane.

"We have the enzyme off of the membrane with all of its components," Barquera said. Once isolated, the researchers observed the enzyme as it moved sodium from the inside to the outside of the cell.

Their study revealed the protein itself is moving the ions along a path through the cell membrane.

"It works in a very different way from enzymes in other bacteria and mitochondria. The catch and release of ions is done by movement of the protein," Barquera said.

Barquera said that, by modifying the protein in various ways, the researchers had identified the site on the protein where the ions begin and end their travel along the protein.

Next they want to map the route the ion takes along the protein.

"We can see the in and out site. Now we want to know the path," Barquera said.


Story Source:

The above story is based on materials provided by Rensselaer Polytechnic Institute. Note: Materials may be edited for content and length.


Journal Reference:

  1. O. Juarez, J. E. Morgan, M. J. Nilges, B. Barquera. Energy transducing redox steps of the Na -pumping NADH:quinone oxidoreductase from Vibrio cholerae. Proceedings of the National Academy of Sciences, 2010; DOI: 10.1073/pnas.1002866107

Cite This Page:

Rensselaer Polytechnic Institute. "Mysterious workings of cholera bacteria uncovered." ScienceDaily. ScienceDaily, 28 July 2010. <www.sciencedaily.com/releases/2010/07/100728121341.htm>.
Rensselaer Polytechnic Institute. (2010, July 28). Mysterious workings of cholera bacteria uncovered. ScienceDaily. Retrieved August 21, 2014 from www.sciencedaily.com/releases/2010/07/100728121341.htm
Rensselaer Polytechnic Institute. "Mysterious workings of cholera bacteria uncovered." ScienceDaily. www.sciencedaily.com/releases/2010/07/100728121341.htm (accessed August 21, 2014).

Share This




More Health & Medicine News

Thursday, August 21, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Possible Ebola Patient in Isolation at California Hospital

Possible Ebola Patient in Isolation at California Hospital

Reuters - US Online Video (Aug. 20, 2014) — A patient who may have been exposed to the Ebola virus is in isolation at the Kaiser Permanente South Sacramento Medical Center. Linda So reports. Video provided by Reuters
Powered by NewsLook.com
Raw: World's Oldest Man Lives in Japan

Raw: World's Oldest Man Lives in Japan

AP (Aug. 20, 2014) — A 111-year-old Japanese was certified as the world's oldest man by Guinness World Records on Wednesday. Sakari Momoi, a native of Fukushima in northern Japan, was given a certificate at a hospital in Tokyo. (Aug. 20) Video provided by AP
Powered by NewsLook.com
Do More Wedding Guests Make A Happier Marriage?

Do More Wedding Guests Make A Happier Marriage?

Newsy (Aug. 20, 2014) — A new study found couples who had at least 150 guests at their weddings were more likely to report being happy in their marriages. Video provided by Newsy
Powered by NewsLook.com
Ebola-Hit Sierra Leone's Freetown a City on Edge

Ebola-Hit Sierra Leone's Freetown a City on Edge

AFP (Aug. 19, 2014) — Residents of Sierra Leone's capital voice their fears as the Ebola virus sweeps through west Africa. Duration: 00:56 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins