Harry MacWilliams used to plate contaminated Dicty cultures onto 
KK2-agar. He would take a plate of Klebsiella (pre-grown on SM or LB 
agar) and resuspend the bacteria in 5ml of sterile KK2 buffer. He would 
collect the cells from the contaminated Dicty culture by centrifugation, 
wash them once in KK2 buffer, resuspend them in about half a mL of the 
Klebsiella suspension, then spread the mix onto KK2-agar (or KK2 plates 
containing 100 micrograms per ml of G418 for Dicty transformed with a 
V18Tn5 vector). The Dicty will clear the bacterial lawn in about 3 days, 
then one can harvest the spores and put them back into HL5.
Kimchi

Am 2013-11-08 10:32, schrieb Damer, Cynthia Kay:
> Dear Colleagues,
>
> My lab is currently experiencing a culture contamination problem that
> I have not experienced previously.  We are culturing Dicty in HL-5
> supplemented with penicillin and streptomycin on plastic sterile
> culture dishes.  The contaminant appears to be very small (less than 
> a
> micron) and spherical and is not able to move.  In addition, it is
> very slow growing.  However, as the contaminant becomes more 
> numerous,
> the Dicty cells become rounded and eventually die.  Unfortunately,
> even when we thaw out strains in new media, the contaminate appears
> again.  We've also tried centrifuging and washing many times and
> greatly diluting the cultures.  This seems to get rid of most of it,
> but it eventually grows up again.
>
> Any advice would be appreciated.
>
> Thanks,
>
> Cynthia
>
> Cynthia K. Damer
> Professor
> Biology Department
> Brooks Hall Room 229
> Central Michigan University
> Mount Pleasant, MI 48859
> (989) 774-3455