Hi Charlotte, In case it matters, we use a pair of fluorescent UV
sterilizing lights (when people are not in the room) on our Dicty
clean table (which has has filtered air flowing across the hooded
table and into the room past the seated user). Yeast hasn't been a
problem. Best wishes, Carl
On Tue, Jul 2, 2013 at 5:27 AM, Professor Paul Fisher
<[log in to unmask]> wrote:
> Dear Charlotte
>
> Yeast should not survive autoclaving (not even as spores), but your filters
> might be contaminated. I would not bother with filtering.
> The other possibility is that the autoclaving conditions are not right.
> Standard would be 121C for 20 min but if you are using large volumes, the
> heating in the central areas of the container will be slower and so may not
> reach the desired temperature early enough.
>
> Also watch out that any post-autoclaving manipulations, additions,
> inoculations might introduce contaminants.
>
> Cheers,
> Paul.
>
> Prof. Paul R. Fisher,
> Chair in Microbiology,
> Deputy Executive Dean,
> Faculty of Science, Technology & Engineering,
> La Trobe University,
> VIC 3086,
> AUSTRALIA.
>
> Tel. + 61 3 9479 2229
> Fax. + 61 3 9479 1222
> Email. [log in to unmask]
> Web. http://fishfam.homeip.net:100/mcbg
>
> La Trobe University - ranked top in Victoria for student satisfaction
> (Sweeney Uni Student Report, 2009)
>
>
> On 2 July 2013 16:31, Pierre Cosson <[log in to unmask]> wrote:
>>
>> Dear Charlotte,
>> What happened to us once: we were using so-called sterile bacteriological
>> plates for Dictyo cultures, and started getting low level infections from
>> time to time, often with yeast. After checking everything, the answer was
>> that the sterile bacteriological plates are not truly sterile. They are
>> produced in a sterile environment, but some lots will contain a few spores.
>> There are two solutions: 1-quick and expensive: use tissue-culture plastic;
>> beware, this will change the behavior of your cells, since Dictyo adheres
>> much better to tissue-culture plastic. 2-cheap: order a lot of
>> bacteriological plates that have been sterilized by irradiation. That costs
>> very little, and solves completely the problem. The only problem is that you
>> need to order a full batch of plates (I think minimum 10-20 boxes).
>> If you are already using tissue-culture plastic, then maybe consider
>> checking the filter of your culture hood. Anyway, autoclaved HL5, filtered
>> or not, is sterile, so this is not the cause of your problems.
>> Best regards
>> Pierre
>>
>>
>> Pierre Cosson
>> Centre Médical Universitaire
>> Dpt of Cell Physiology and Metabolism
>> 1 rue Michel Servet
>> CH 1211 Geneva 4, Switzerland
>>
>> [log in to unmask]
>> Tel. (41) 22 379 5293
>> Fax (41) 22 379 5338
>>
>> On 1 juil. 2013, at 22:15, charlotte Riviere
>> <[log in to unmask]>
>> wrote:
>>
>> Dear all,
>>
>> We had some problem in culturing DH1 strain lately in HL5 medium
>> (Formedium) : we have lots of yeast appearing after few days that we can
>> not get rid off.
>>
>> Is there any culture tricks to avoid such yeast contamination?
>> (The medium are autoclaved and filtered @0.22 µm)
>>
>> Best
>>
>> Charlotte
>>
>> --
>> Charlotte Riviere
>> Institut Lumière Matière (UMR5306 UCB Lyon 1 / CNRS)
>> Domaine Scientifique de la Doua
>> Bâtiment Léon Brillouin
>> 43 Boulevard du 11 novembre 1918
>> 69622 Villeurbanne France
>> Tél : +(33) (0)4 72 43 27 96 Fax : +(33) (0)4 72 43 26 48
>> [log in to unmask]
>>
>>
>
--
Carl Franck
Associate Professor, Physics
Clark Hall E18, 525
Cornell University
lab phones: 607-255-5215 and 255-3562 (long ring for messages)
home phone: 257-6969 (until 10PM)
please note that I frequently use Google Voice to send calls, but do
not receive them on that number
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