Why is fluoride toxic to bacterial cells?

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And does it similarly affect the cells of organisms of any other biological Kingdoms?
 

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  • #2
DaveC426913
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And does it similarly affect the cells of organisms of any other biological Kingdoms?

How did the results of your 'fluoride toxicity' Google turn out?
 
  • #3
506
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Fluoride is notoriously corrosive, of course. Think hydrofluoric acid.

More specifically - fluoride can serve as a nucleophile, and can serve as a phosphatase inhibitor (which would mean it can do so to any and all organisms, at least in principle). Substitution of fluorine for hydrogen can result in a compound that is more difficult for the organism to detoxify and excrete, which may be deleterious.

I'm fairly sure that fluoride toxicity is probably extensively covered somewhere online, as it can also do unpleasant things like decrease calcium levels in humans, which can wreak all kinds of havoc.
 
  • #4
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Googling 'fluoride toxicity' doesn't readily yield information about fluorine's absorption by cells and/or reactions with cellular components such as organelles and enzymes.
 
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  • #5
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Fluoride is notoriously corrosive, of course. Think hydrofluoric acid.

The corrosive part is, to put it simply, the hydrogen ion, not the fluoride part. Also, you are confusing fluoride (F-) with fluorine (F2).
 
  • #6
506
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The corrosive part is, to put it simply, the hydrogen ion, not the fluoride part. Also, you are confusing fluoride (F-) with fluorine (F2).

My bad. I seem to be in the midst of a burst of thinking about halogen chemistry and got my wires crossed.

Googling 'fluoride toxicity' doesn't readily yield information about fluorine's absorption by cells and/or reactions with cellular components such as organelles and enzymes.

Sodium fluoride is a fairly well known inhibitor of certain phosphatases. It's even sold commercially as a protease inhibitor for use in biochemistry labs. It's also used as an inhibitor for one of the glycolytic enzymes as well.

Are you looking for something in particular?
 
  • #7
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Are you looking for something in particular?

I want to know how it (fluorine and/or fluoride) interacts with what to cause cell death.
 
  • #8
506
14
That should be phosphatase inhibitor in my last post, not protease inhibitor.

I want to know how it (fluorine and/or fluoride) interacts with what to cause cell death.

Well, we've already mentioned a couple - interference with metabolism (inhibition of the glycolytic enzyme enolase), inhibition of phosphatases (which are involved in the regulation of numerous cellular functions), and will form insoluble precipitates with calcium, which is an essential trace element.

If more detail is needed, I will have to defer to http://www.ncbi.nlm.nih.gov/pubmed" [Broken], as I'm not familiar with the toxicology literature on this topic.
 
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  • #9
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The fluoride ion, not the hydrogen ion, is the source of toxicity. Fluorine (the element) is extremely electrophilic (wants one more electron pair so it can complete its p-shell and fool itself into believing that it's neon). Fluoride (the ion) has obtained only one of the two electrons it wants, and it's desperate for one more. So fluoride will steal -- or borrow -- a stray electron from *anything*, which is one of the reasons that it's so corrosive/reactive. Introduction of an electrophile to a biological system will probably disrupt electron transport (energy metabolism), bind to nitrogen-containing compounds like proteins or nucleobases, and generally -- because of its size -- prevent the molecule's proper alignment or conformation.
 
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  • #10
The fluoride ion, not the hydrogen ion, is the source of toxicity. Fluorine (the element) is extremely electrophilic (wants one more electron pair so it can complete its p-shell and fool itself into believing that it's neon). Fluoride (the ion) has obtained only one of the two electrons it wants, and it's desperate for one more. So fluoride will steal -- or borrow -- a stray electron from *anything*, which is one of the reasons that it's so corrosive/reactive. Introduction of an electrophile to a biological system will probably disrupt electron transport (energy metabolism), bind to nitrogen-containing compounds like proteins or nucleobases, and generally -- because of its size -- prevent the molecule's proper alignment or conformation.

F- is a fairly good nucleophile due to high electron density. I don't possibly understand how it can act as an electrophile. If you have sources which support your statement please post their links.

In addition, elemental fluorine has 7 electrons in its outermost shell, so it needs one more electron and not an electron pair to complete its octet. Therefore F- will not accept anymore electrons (also due to absence of vacant d-orbitals).

At OP,
Mike H has already given some useful information.
I don't know the cause of fluoride toxicity, but this might shed further light.
http://en.wikipedia.org/wiki/Fluoride#Toxicology
http://en.wikipedia.org/wiki/Fluoride_poisoning
 
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  • #11
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i stand corrected.
 
  • #13
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Here's one: Electrophilicity Index Parr, R. G.; Szentpaly, L. v.; Liu, S. J. Am. Chem. Soc.; (Article); 1999; 121(9); 1922-1924. doi:10.1021/ja983494x
 
  • #14
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I also forget to mention F2 addition to alkene bonds.
 
  • #15
Here's one: Electrophilicity Index Parr, R. G.; Szentpaly, L. v.; Liu, S. J. Am. Chem. Soc.; (Article); 1999; 121(9); 1922-1924. doi:10.1021/ja983494x

I do not have access to the article so please post excerpts from the article which support your statement.
 
  • #16
I also forget to mention F2 addition to alkene bonds.

Fluorine doesn't give simple addition reactions because of its high reactivity.
 

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