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Ah, forgive me if I gave the wrong idea with the word "Standard". I'm
not advocating some sort of design-by-committee for DIYbio protocols,
just suggesting that if a n00b asks "how do I make my first gel?", we
suggest protocols that are:
A) As close to home as possible; methylene blue is a very easy dye to
get a hold of, even if it sucks somewhat
B) As safe and legally unencumbered as possible
C) As easy and user-friendly as possible
That's because, to me, when a person says "how do I run a gel?",
they're asking "How would someone who is totally new to this run a
gel?", whereas when someone asks "What's the best dye to use for high
sensitivity?", they mean just that, and answers can become more complex.
Not that you're wrong to use or recommend EtBr, though I would
*recommend* adding a responsible warning that its safety is under
decades-long dispute, some common methods for disposal (bleach!)
actually make it more toxic, and it may have legal encumbrance in some
areas.
On Fri, 5 Jul 2013 07:07:54 -0500
Josiah Zayner <josiah.zayner@gmail.com> wrote:
> I think most University disposal of EtBr(at least in the US) is
> self-policing, which is great. The less of a potential hazardous
> substance in the world the better.
>
> I just found this journal article, no joke, about an internet mailing
> list(newsgroup) discussion about EtBr disposal from 1994, no joke.
>
> https://docs.google.com/file/d/0B_R75gIJvkFUTTR6WDI0c1k2NVE/edit?usp=sharing
>
> I am glad this issue has not been resolved since 1994 and no new
> arguments are being made, haha.
>
> The whole "community standards" idea is interesting.
>
> This next part is not meant to be about EtBr specifically
> Who decides what should be a community standard? I assume someone
> would say "the community". Is there a vote? Do a few people just try
> and push what they think it should be?
> In most mainstream Science there are only two things that are used to
> determine if something becomes akin to a "community standard".
>
> 1. Does it work.
> 2. Is it legal to work with.
>
> To me Science is about doing Science. Maybe I am reckless. But
> deciding what chemical I think people should use for electrophoresis
> or as is apparent recently on this mailing list, what power supply
> people should use, seems bureaucratic. No one cares what chemical or
> power supply you are using if you are doing good Science.
> No journal is going to say, "Well his Science is good but he used
> EtBr and a sketchy power supply and we don't want to promote that
> soooo we won't publish it."
>
> I mean bureaucracy is why so many people I know want to leave
> mainstream Science and it seems to be rearing it's head here.
>
> I hope we as a group are going to give people the most benefits in our
> doubts and do Scientific work and judge people's Scientific work
> instead of what and how they do it.
>
>
>
>
> On Fri, Jul 5, 2013 at 4:22 AM, Cathal Garvey
> <cathalgarvey@cathalgarvey.me>wrote:
>
> > <snip>
> >
> > > There is no disregard for MSDS. Search online. Ethidium Bromide
> > > disposal is not regulated by the EPA. Most states do not have
> > > regulations regarding it's disposal either.
> >
> > It is regulated in some other *countries* though, meaning that even
> > if we all accept that it's not as dangerous as commonly thought,
> > we're better off suggesting alternative gel dye methods as
> > "community standards" that we can expect to be equally applicable
> > to all. Those with a need for higher gel resolution can upgrade to
> > something more effective later on.
> >
> > > I am sure Ethidium Bromide is mutagenic if inhaled in high
> > > quantities or consumed in large quantities or placed it on the
> > > skin in high quantities. I have worked with Ethidium Bromide for
> > > ~10 years and I can't recall it ever even touching my skin... I
> > > wear gloves as when working with it as I assume most people wear
> > > gloves when doing lab work especially with potentially hazardous
> > > chemicals? Again, it would seem only logical that if Ethidium
> > > Bromide was so dangerous there would be an outbreak of cancer
> > > amongst professional Scientists but there is not...
> >
> > We've actually had discussions intermittantly about the safety or
> > lack of regarding EtBr, and I've seen others off-list between
> > old-as-the-hills molecular biologists.
> >
> > Also, there's this:
> > https://en.wikipedia.org/wiki/Ethidium_bromide#Health_risks
> >
> > It does appear that, while EtBr is highly mutagenic in the Ames test
> > when treated with liver homogenate, there's little evidence that it
> > has the same level of mutagenicity in humans under normal
> > circumstances. The studies mentioned in the Wikipedia article do
> > not appear to study teratogenicity, so the safest option would be
> > to assume it is a mild to moderate teratogen, given its very mixed
> > reputation: avoid exposure months before making babies (either
> > gender) or while pregnant.
> >
> > However, all that said, EtBr is still regulated in some countries, I
> > think. I don't know whether it was law or merely policy, but EtBr
> > had to be handled by a waste disposal specialist in Ireland in my
> > local University. We had special decanters with activated charcoal
> > teabags to collect post-gel EtBr waste, and the "teabags" were sent
> > for disposal.
> >
> > Given its reputation, difficulty in acquisition in some places,
> > dubious legal standing, and the fact that you need UV to image
> > (even seconds of UV transillumination slash transformation/cloning
> > efficiency rates), I'm still in favour of alternatives like
> > Sybr-Safe.
> >
> > -Cathal
> >
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> > To view this discussion on the web visit
> > https://groups.google.com/d/msgid/diybio/20130705102259.5371d9c4%40Neptune
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> >
> >
> >
>
Re: [DIYbio] EtBr Toxicity etc. (Was: electrophoresis power supply)
5:46 AM |
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