Hes not a dentist, but ChrisTOPher Miller1 is focused on fluoride. Two studies from his Brandeis University lab provide new insights into the mechanisms2 that allow bacteria to resist fluoride toxicity4, information that could eventually help inform new strategies for treating harmful bacterial5 diseases. The studies appear in The Journal of General Physiology6 .Although most animal cells are protected from direct exposure to fluoride, this toxic3 element is a serious threat to single-celled organisms like bacteria and yeast7. As a result, their plasma8 membranes10 carry two different types of proteins to help rid the cell of unwanted fluoride: fluoride/hydrogen antiporters use energy to actively11 pump fluoride uphill out of the cell; and fluoride-specific Fluc ion channels mediate12 the passive downhill movement of fluoride across the cell membrane9.Fluc channels were first identified by Miller and colleagues very recently, in 2013. In the September issue of JGP, they now provide the first quantitative13 data demonstrating how these passive channels can help protect bacteria from fluoride. The authors found that fluoride accumulates in E. coli lacking Fluc when the external environment is acidic. In such acidic environments, fluoride enters the cell in the form of HF -- which easily permeates14 the membrane -- and breaks down in the cells lower acidity15; Fluc provides a means of escape for the highly charged fluoride ions. They also found that bacteria proliferation was stalled by high fluoride exposure, indicating that targeting Fluc channels with antibiotics16 could be an effective way to slow bacterial growth.In the August issue of JGP, Miller and colleagues unearthed17 new information about fluoride/hydrogen antiporters -- also recently discovered -- which are part of the CLC superfamily of proteins that are known for exporting chloride. The authors explored why this subset demonstrates higher selectivity for fluoride -- which is essential for their function because chloride is so much more abundant in the environment -- and were able to determine key structural18 differences that could account for the preferential selectivity of fluoride.
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1 miller n.磨坊主 参考例句： Every miller draws water to his own mill.磨坊主都往自己磨里注水。 The skilful miller killed millions of lions with his ski.技术娴熟的磨坊主用雪橇杀去世了上百万头狮子。
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