Featured Research

from universities, journals, and other organizations

How bacteria fight fluoride in toothpaste and in nature

Date:
December 23, 2011
Source:
Yale University
Summary:
Researchers have uncovered the molecular tricks used by bacteria to fight the effects of fluoride, which is commonly used in toothpaste and mouthwash to combat tooth decay.

Yale researchers have uncovered the molecular tricks used by bacteria to fight the effects of fluoride, which is commonly used in toothpaste and mouthwash to combat tooth decay.
Credit: mathom / Fotolia

Yale researchers have uncovered the molecular tricks used by bacteria to fight the effects of fluoride, which is commonly used in toothpaste and mouthwash to combat tooth decay.

In the Dec. 22 online issue of the journal Science Express, the researchers report that sections of RNA messages called riboswitches -- which control the expression of genes -- detect the build-up of fluoride and activate the defenses of bacteria, including those that contribute to tooth decay.

"These riboswitches are detectors made specifically to see fluoride," said Ronald Breaker, the Henry Ford II Professor and chair of the Department of Molecular, Cellular and Developmental Biology and senior author of the study.

Fluoride in over-the-counter and prescription toothpastes is widely credited with the large reduction in dental cavities seen since these products were made available beginning in the 1950s. This effect is largely caused by fluoride bonding to the enamel of our teeth, which hardens them against the acids produced by bacteria in our mouths. However, it has been known for many decades that fluoride at high concentrations also is toxic to bacteria, causing some researchers to propose that this antibacterial activity also may help prevent cavities.

The riboswitches work to counteract fluoride's effect on bacteria. "If fluoride builds up to toxic levels in the cell, a fluoride riboswitch grabs the fluoride and then turns on genes that can overcome its effects," said Breaker.

Since both fluoride and some RNA sensor molecules are negatively charged, they should not be able to bind, he notes.

"We were stunned when we uncovered fluoride-sensing riboswitches" said Breaker. "Scientists would argue that RNA is the worst molecule to use as a sensor for fluoride, and yet we have found more than 2000 of these strange RNAs in many organisms."

By tracking fluoride riboswitches in numerous species, the research team concluded that these RNAs are ancient -- meaning many organisms have had to overcome toxic levels of fluoride throughout their history. Organisms from at least two branches of the tree of life are using fluoride riboswitches, and the proteins used to combat fluoride toxicity are present in many species from all three branches.

"Cells have had to contend with fluoride toxicity for billions of years, and so they have evolved precise sensors and defense mechanisms to do battle with this ion," said Breaker, who is also an investigator with the Howard Hughes Medical Institute. Now that these sensors and defense mechanisms are known, Breaker said, it may be possible to manipulate these mechanisms and make fluoride even more toxic to bacteria. Fluoride riboswitches and proteins common in bacteria are lacking in humans, and so these fluoride defense systems could be targeted by drugs. For example, the Yale team discovered protein channels that flush fluoride out of cells. Blocking these channels with another molecule would cause fluoride to accumulate in bacteria, making it more effective as a cavity fighter.

Fluoride is the 13th most common element in Earth's crust, and it is naturally present in high concentrations throughout the United States and elsewhere. Its use in toothpaste and its addition to city water supplies across the United States sparked a controversy 60 years ago, and the dispute continues to this day. In the United Kingdom, and in other European Union countries, fluoride is used to a much lesser extent due to fierce public opposition.

The new findings from Yale only reveal how microbes overcome fluoride toxicity. The means by which humans contend with high fluoride levels remains unknown, Breaker notes. He adds that the use of fluoride has had clear benefits for dental health and that these new findings do not indicate that fluoride is unsafe as currently used.

Other Yale authors of the paper include: Jenny L. Baker, Narasimhan Sudarsan, Zasha Weinberg and Adam Roth.

The work was funded by the National Institutes of Health. Breaker is co-founder of a biotechnology company that has licensed intellectual property on riboswitches from Yale.


Story Source:

The above story is based on materials provided by Yale University. The original article was written by Bill Hathaway. Note: Materials may be edited for content and length.


Journal Reference:

  1. Jenny L. Baker, Narasimhan Sudarsan, Zasha Weinberg, Adam Roth, Randy B. Stockbridge, and Ronald R. Breaker. Widespread Genetic Switches and Toxicity Resistance Proteins for Fluoride. Science, 22 December 2011 DOI: 10.1126/science.1215063

Cite This Page:

Yale University. "How bacteria fight fluoride in toothpaste and in nature." ScienceDaily. ScienceDaily, 23 December 2011. <www.sciencedaily.com/releases/2011/12/111222142450.htm>.
Yale University. (2011, December 23). How bacteria fight fluoride in toothpaste and in nature. ScienceDaily. Retrieved August 20, 2014 from www.sciencedaily.com/releases/2011/12/111222142450.htm
Yale University. "How bacteria fight fluoride in toothpaste and in nature." ScienceDaily. www.sciencedaily.com/releases/2011/12/111222142450.htm (accessed August 20, 2014).

Share This




More Health & Medicine News

Wednesday, August 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

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
101-Year-Old Working Man Has All The Advice You Need

101-Year-Old Working Man Has All The Advice You Need

Newsy (Aug. 19, 2014) Herman Goldman has worked at the same lighting store for almost 75 years. Find out his secrets to a happy, productive life. Video provided by Newsy
Powered by NewsLook.com
Researcher Testing on-Field Concussion Scanners

Researcher Testing on-Field Concussion Scanners

AP (Aug. 19, 2014) Four Texas high school football programs are trying out an experimental system designed to diagnose concussions on the field. The technology is in response to growing concern over head trauma in America's most watched sport. (Aug. 19) Video provided by AP
Powered by NewsLook.com
American Ebola Patient Apparently Improving, Outbreak Is Not

American Ebola Patient Apparently Improving, Outbreak Is Not

Newsy (Aug. 19, 2014) Nancy Writebol, an American missionary who contracted Ebola, is apparently getting better, according to her husband. The outbreak, however, is not. Video provided by Newsy
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