Some manufacturers of filters have wetting agents 
in their filters, a reasonable precaution would 
be to discard the first 50ml or so of liquid 
through the filter. I have to agree, however, 
that degree of autoclaving can be a significant 
variable in Dicty growth.

Danny


>We also use Formedium and see little variation 
>in doubling times. We are picky with the 
>autoclaving, though. If your medium is brown 
>Dicty won't grow well ... does not like caramel 
>! To test if that's the culprit, make a batch of 
>sterile-filtered, non-autoclaved medium. Often 
>relieves the problems.
>Cheers,
>
>Thierry
>
>
>On 21 Jul 2010, at 17:00, Robert Insall wrote:
>
>>  We were one of the labs that suggested vitamin 
>>supplements to counter precisely this problem. 
>>Cells would grow at different speeds depending 
>>on background and in particular density (cells 
>>grew better above a threshold density in the 
>>region of 10^6/ml).  The vitamins (and also not 
>>autoclaving the sugar; we made a 20x supplement 
>>with both) made the problem completely go away. 
>>They also slightly improved the doubling time. 
>>They do, however, inhibit development somewhat.
>>
>>  Of course, that doesn't mean it'll answer your 
>>problem.  Also, we moved labs and now it isn't 
>>apparently necessary - we haven't had a 
>>recurrence, and don't use the vitamins any more.
>>
>>  Have you raised the issue with formedium? 
>>They would want to know.  But our formedium HL5 
>>seems fine.
>>
>>	Robert
>>
>>  On 21 Jul 2010, at 15:43, Christian Hammann wrote:
>>
>>>  Is this also observed in other labs?
>>>  What is the usual doubling time of AX2 in your hands?
>>>  How constant is that doubling time?
>>>  How many of you have tried to supplement the 
>>>medium with vitamins, as stated in the 
>>>technical comments on Dictybase, and how 
>>>successful was that?
>>
>>  --------------------------------------
>>  Professor Robert Insall
>>  CR-UK Beatson Institute for Cancer Research
>>  Switchback Road, Bearsden
>>  Glasgow G61 1BD, UK
>>
>>  Tel.  (0/44) 141 330 4005
>>  Web http://www.beatson.gla.ac.uk/robert_insall
>>  --------------------------------------
>
>--
>================================================
>Dr. Thierry Soldati, Senior Lecturer
>Department of Biochemistry
>University of Geneva
>30 quai Ernest Ansermet, Sciences II
>CH-1211-Genève-4, Switzerland
>
>Tel: +41-22-379-6496
>Fax: +41-22-379-3499
>email: [log in to unmask]
>http://www.unige.ch/sciences/biochimie/Research/Soldati.html
>================================================