Navigation Links
Bacteria battle against toxic fluoride
Date:12/22/2011

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
keeleyj@hhmi.org
301-215-8858
Howard Hughes Medical Institute
Source:Eurekalert

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:
*Name:
*Comment:
*Email:
(Date:3/2/2017)... Australia , March 2, 2017 Australian ... Ltd (ASX: CYP), has signed an agreement with ... from the Monash Biomedicine Discovery Institute and Department of ... to conduct a further preclinical study to support the ... treatment of asthma.  Asthma is a ...
(Date:2/27/2017)... 27, 2017   Strategic Cyber Ventures , the ... led a $3.5 million investment in  Polarity , the ... Ventures is DC based and is led by cybersecurity ... . Ron Gula , also a longtime cybersecurity ... in this series A round of funding. This new ...
(Date:2/21/2017)... -- Der weltweite Biobanking-Sektor wird bis zum ... mit mehr als 50 Vertretern aus verschiedenen Branchen wurde aber ... diese Prognose zu realisieren. ... Zu den Schwierigkeiten für ... für die Biobank, die Implementierung Zeit sparender Technologien, ein ...
Breaking Biology News(10 mins):
(Date:3/24/2017)... Sinovac Biotech Ltd. ("Sinovac" or the "Company") (NASDAQ: SVA), a leading ... announced that its board of directors has amended its shareholder rights ... 27, 2017 to March 27, 2018. The amendment was not in response ... ... Biotech Ltd. is a China -based biopharmaceutical company ...
(Date:3/24/2017)... 2017   Sienna Biopharmaceuticals, Inc. , a privately ... that Richard Peterson will join the company ... Peterson, who brings more than two decades of global ... is retiring at the end of April but will ... joins Sienna from Novan, Inc., where he served as ...
(Date:3/23/2017)... ... March 23, 2017 , ... AxioMed ... both viscous and elastic characteristics when deformed, which is identical to how the ... gently absorb compressive forces and return to its natural state along a hysteresis ...
(Date:3/23/2017)... , Mar 23, 2017 Research and ... Global Markets" report to their offering. ... The Global Market ... Billion in 2016 at a CAGR of 8.9%, ... and non-energetic bioproducts into seven major product segments: bio-derived chemicals, ...
Breaking Biology Technology: