Pipetting, contamination....

[Jose de las Heras]

"DK" <dk from no.email.thankstospam.net> wrote in message 
news:1LqDh.471$RT2.5 from newsfe06.lga...
>
> Everyone I know who does "microbiology" outside of sterile hood
> is engaged in the practice of flaming necks of every bottle and
> flask they use. When asked why they are doing it, the only answer
> ever given is "to keep it sterile". Problem is, for as far as I can tell,
> the way it is done, it's a completely useless exercise in at least
> 9 out of 10 times.

This reminds me of another "bug" of mine.
I used to see in a microbiology lab everybody working on their bench with 
the bunsen on, next to the plates etc.
Why?
"to keep the air around clean".
However, I just imagine the air rising by the bunsen, and being replaced 
with colder "dirty" air from outside, right over the plates...
Does it actually serve any purpose at all? Or is it another lab myth?

Jose

PS: regarding filter tips... I would agree that for most purposes they are 
superfluous. But we do avoid 32P contamination of our communal pipettes, 
which was a routine situation until introducing the filter tips. I also tend 
to use them when doing transformations etc, for teh same reason that I'd be 
uneasy to use a pipette to work with RNA that I know was used heavily to put 
RNAse on DNA preps...