Re: Transformation questions

Actually, leaving the cells to "overcook" will usually destroy all
antibiotics present; it's only unused media that really needs boiling or
other such treatment before disposal. In the case of chloramphenicol,
I'll probably just add some resistant cells to unused media and incubate
in order to destroy the broth, then boil-kill and UV inactivate.

Microwaves don't explicitly damage DNA.
However, UV does, and I would advocate using UV to mince DNA before
disposal, especially if the DNA contains medically significant (i.e.
AmpR, maybe Chlor?) antibiotic resistance genes. Most labs have UV
transilluminators for Gel electrophoresis, even though blue illumination
is more all-round useful (precisely because it doesn't mince DNA).

So, if I were working with E.coli, which can't survive boiling, I'd
simply boil cellular waste in a glass beaker or flask, then put the
container on a UV illuminator for 5 minutes before disposal.

If I were working with B.subtilis, I'd autoclave rather than boiling,
and do the same.

Clearly, I wouldn't be so strict with DNA that was proven to have no
ecological consequences; no resistance genes, no ecological-unknowns. A
plasmid containing only GFP and plasmid maintenance genes is hardly
worth worrying about, for example.

Of course, opinions differ, and we've had animated discussions here in
the past on this issue; whether to bother destroying antibiotics,
whether to bother destroying DNA.

On 27/01/12 08:54, Mega wrote:
> Ah, you only want to dispose of the plasmids left from transformation?
>
> On 27 Jan., 09:53, Mega <masterstorm...@gmail.com> wrote:
>> Have you considered using UV-radiation? I saw one on a TV 'show-
>> documentation-infotainment' which costed about 20 bucks and they
>> tested if it really worked.
>>
>> And, surprisingly, it really worked fine!
>>
>> Maybe Microwave sterilization could also work when it damages the DNA
>> ( not only heat up the bacteria). Or you add e.g. ampicillin to kill
>> the bacteria and then heat the whole pot to destroy the amp.
>>
>> On 26 Jan., 23:17, Cathal Garvey <cathalgar...@gmail.com> wrote:
>>
>>
>>
>>
>>
>>
>>
>>> Actually, a control Bacillus plasmid I'm going to be using is Chloramphenicol resistant: I hadn't realised it was heat resistant! I'd better imagine up a disposal procedure..
>>
>>> Venkatesh Srinivas <m...@endeavour.zapto.org> wrote:
>>>> On Wed, Jan 25, 2012 at 11:05 PM, Tom Randall <tarand...@gmail.com>
>>>> wrote:
>>>>> ...
>>>>> I am sure there are others. No environmental issues with amp or
>>>> others
>>>>> if you autoclave everything before you dispose of it, this will
>>>>> inactivate most antibiotics that I am aware of. If there are any that
>>>>> can withstand autoclaving I would be interested in knowing. This is
>>>>> why one normally adds antibiotics to media after autoclaving the
>>>> media
>>>>> and cooling to ~55-60C to avoid their inactivation.
>>>>> Go wild!
>>>>> ...
>>
>>>> I believe chloramphenicol is thermostable; should survive autoclaving.
>>>> Not commonly used in DIYbio I imagine though...
>>
>>>> --vs;
>>
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