Skip to comments.Biosynthesis of methylmercury discovered
Posted on 02/13/2013 1:45:56 AM PST by neverdem
While we all know mercury is poisonous it is methylmercury, the organic form, that bioaccumulates in food webs and is highly toxic. It's been acknowledged for years that methylmercury is produced by microorganisms far down the food chain, but what has not been known is how they do it. US-based researchers at Oak Ridge National Laboratory in Tennessee have now identified the genes, and hence the proteins, involved in mercury methylation and suggest that the pathway is common for all mercury methylating microorganisms.
Using gene deletion, Jerry Parks' team showed that two genes are key components of bacterial mercury methylation, relating to a corrinoid protein that acts as a methyl carrier and a ferredoxin protein that reduces the corrinoid protein's cofactor. What is still not apparent, however, is why these bacteria have evolved to methylate mercury at all.
J M Parks et al, Science, 2013, DOI: 10.1126/science.1230667
And didn’t they have some type of worldwide summit where they agreed that there would be a push to limit mercury usage or manufacturing? The timing seems uncanny. Wonder if someone is going to step in an corner the mercury market now while it’s being “made” scarcer which will drive the prices up of course.
Maybe a light bulb will go on in someones brain and the mercury filled pig tails will be illegal.
There would have been ample funding to figure this out years ago if mercury had been blamed for global warming. ;’) Thanks neverdem.
Google the words “Karen Wetterhahn mercury” to find out how dangerous methyl mercury is.
Dr. Wetterhahn had been using mercury compounds her whole career (her research specialty was toxic metals poisoning). She dripped a tiny droplet of Hg(CH3)2 on her glove. The original story said she was wearing two pairs of gloves (although the Wikipedia article mentions only “her latex gloved hand” which seems to be a walk-back from the double-gloved story).
In any event, the methyl mercury penetrated the glove, penetrated her skin, and killed her after a six-month latency period. She was excreting more than four times the toxic concentration of Hg in her urine six months after the exposure incident.
I wonder why she wasn’t using a glove box - big thick gloves and proper venting.
My father was twice poisoned by mercuric chloride in a lab - contributed to mental illness that led to his death.
Both the original story and the Wikipedia article said she was working with the methyl-Hg inside a fume hood.
The original article said she was double-gloved and that the spill was so tiny she didn't even notice it. The Wiki article walks that back a bit, saying she was in contact with 'several drops' and was protected only by "latex."
She used methyl-Hg all the time, and had been using it frequently for years. It is apparantly a very good molecule for calibrating NMR equipment, having a clear strong isolated resonance at a frequency close to that of the cadmium atoms she was studying.
Maybe she got too familiar with the procedure. Maybe she was in a hurry, or distracted by something.
When you're working with methyl-Hg, there is no margin for error. You're dancing with death at all times it's in your hands, or even near you. It's just as dangerous as a test tube full of Ebola virus, except that it's not contagious. Or not as contagious anyway. It can't reproduce and spread.
The original article said it's a colorless, odorless, clear liquid. Looks like water.
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