Navigation Links
Bacteria battle against toxic fluoride

Regular use of fluoride-containing toothpaste and mouthwash has long been known to strengthen the enamel on teeth. But new research by Howard Hughes Medical Institute (HHMI) scientists finds that fluoride also has dramatic effects on bacteria inside the mouth -- including those that form plaque and can cause cavities.

HHMI researcher Ronald Breaker of Yale University has discovered the cellular chain of events that occurs inside a bacterium after it encounters fluoride in its environment. His team's findings reveal that many bacteria try to fend off fluoride which the organisms treat as a toxic substance by throwing it out. The presence of such a transport system indicates that fluoride itself has antimicrobial properties, Breaker said. The findings are published online in Science Express on December 22, 2011.

Breaker's lab studies non-coding RNA, stretches of genetic material that play regulatory roles in the cell instead of coding for proteins. Using different computer algorithms, he and his colleagues analyze the genomes of organisms to identify signature sequences in genetic material that likely indicate the presence of noncoding RNA. Among the types of non-coding RNAs they find are regulatory molecules called riboswitches. Normally, the role of a riboswitch is easy to deduce: Riboswitches are attached to the genes that they regulate. If the gene is needed to produce a certain compound, the riboswitch is usually sensitive to that compound, so when its level increases or decreases in the cell, the riboswitch can cause more or less to be made. Aside from their interest in the biology of riboswitches, Breaker's group is studying these genetic switches because they could represent new drug targets and might be used to control the activity of genes inserted into cells as gene therapies.

In a recent set of experiments, Breaker's team identified a new riboswitch that was attached to a handful of genes with vague or unknown functions. They were stumped. "We knew we had a riboswitch but we didn't know what it bound," says Breaker. "And we were very intrigued because it was one of the only non-coding RNAs we've ever found that's present in both bacteria and archaea. That suggests that it has ancient origins and an important role in the cell," he notes.

So Breaker and his colleagues put the RNA in a test tube and began to mix in different chemicals, observing whether or not they bound to the riboswitch. They worked through a long list of more common chemicals before they stumbled on fluoride. The addition of fluoride was an accident -- fluoride was a contaminant in a sample of a different chemical they were testing.

Once Breaker's group found that the riboswitch bound to fluoride, they were able to show that the genes controlled by the riboswitch are those that help the cell fight the toxicity of fluoride. Fluoride, a negatively charged ion, binds aggressively to some metabolites and essential enzymes. If fluoride floods a cell, it can quickly shut down cellular processes. The fluoride-sensing riboswitch, Breaker's team discovered, turns on a gene coding for ion channels that transport fluoride back out of the cell.

"This riboswitch is detecting fluoride buildup in the cell and turning on genes to help overcome that buildup," says Breaker. Whether or not the riboswitch is successful, and fast enough, determines whether a bacterium can fight the effects of fluoride.

"Our data not only help explain how cells fight the toxicity of fluoride, but it also gives us a sense of how we might be able to enhance the antimicrobial properties of fluoride," says Breaker. "In the future we might be able to use this knowledge to make fluoride even more toxic to bacteria." Blocking the fluoride channel, for example, makes cells 200 times more sensitive to fluoride, the researchers showed. Finding other ways to enhance fluoride's effectsby inactivating the riboswitch or shutting off other downstream genescould make fluoride an even better antimicrobial agent.

Contact: Jim Keeley
Howard Hughes Medical Institute

Related biology news :

1. Disinfectants can make bacteria resistant to treatment
2. H. Pylori bacteria may help prevent some esophageal cancers
3. Scientists discover bacteria that can cause bone infections
4. Waste from gut bacteria helps host control weight, UT Southwestern researchers report
5. Gene against bacterial attack unravelled
6. Predatory bacterial swarm uses rippling motion to reach prey
7. Bacteria manage perfume oil production from grass
8. Nature study demonstrates that bacterial clotting depends on clustering
9. Battling bacteria in the blood: Researchers tackle deadly infections
10. Shifts in soil bacterial populations linked to wetland restoration success
11. New bacteria discovered in raw milk
Post Your Comments:
(Date:6/2/2016)... NEW YORK , June 2, 2016   The ... (Weather), is announcing Watson Ads, an industry-first capability in which ... advertising, by being able to ask questions via voice or ... Marketers have long ... with the consumer, that can be personal, relevant and valuable; ...
(Date:6/1/2016)... YORK , June 1, 2016 ... Technology in Election Administration and Criminal Identification to Boost ... to a recently released TechSci Research report, " Global ... By Region, Competition Forecast and Opportunities, 2011 - 2021", ... 24.8 billion by 2021, on account of growing security ...
(Date:5/20/2016)... , May 20, 2016  VoiceIt is excited ... with VoicePass. By working together, VoiceIt ...  Because VoiceIt and VoicePass take slightly different approaches ... increases both security and usability. ... about this new partnership. "This marketing ...
Breaking Biology News(10 mins):
(Date:6/27/2016)... 2016  Global demand for enzymes is forecast ... to $7.2 billion.  This market includes enzymes used ... biofuel production, animal feed, and other markets) and ... Food and beverages will remain the largest market ... of products containing enzymes in developing regions.  These ...
(Date:6/27/2016)... ... June 27, 2016 , ... Newly created 4Sight ... solutions to the healthcare market. The company's primary focus is on new product ... marketing strategies that are necessary to help companies efficiently bring their products to ...
(Date:6/24/2016)... SAN DIEGO , June 24, 2016 /PRNewswire/ ... that more sensitively detects cancers susceptible to PARP ... individual circulating tumor cells (CTCs). The new test ... of HRD-targeted therapeutics in multiple cancer types. ... therapies targeting DNA damage response pathways, including PARP, ...
(Date:6/23/2016)... Mass. , June 23, 2016   ... development of novel compounds designed to target cancer ... napabucasin, has been granted Orphan Drug Designation from ... the treatment of gastric cancer, including gastroesophageal junction ... stemness inhibitor designed to inhibit cancer stemness pathways ...
Breaking Biology Technology: