need to identify a contaminant in the cell culture

[Sudheendra Rao N R]

@ Val: Yup, doing that. getting rid of contaminated cell vials and also
doing routine stuff with incubators. Have ordered amphotericin B..I thought
ID would help to combat this pain in a more precise way..
@ Jasenka: Colonies look soft and are soft. Do they dont seem to grow into
agar rather they spread on the surface. I again want to mention the claw
like projections from the margin of colonies..like flares from sun! i have
no idea whether this description can help ID it..but thats what it is.

more ID tips are eagerly awaited.

regards
sudheendra.

On Thu, Jul 30, 2009 at 8:20 PM, Jasenka Pigac <pigac from irb.hr> wrote:

> It is hard to tell from your description, I aminclined to think about
> actinomycetes, due to a rather slow growth and resistancy. Are the colonies
> soft or like leather? Do they grow into agar or stay on its surface?
>
>  Hi, all,I recently found this contaminant in one of the thawed vials..i
>> want
>> to ID it.i dont know how to post pictures in this list..but i will give
>> description..
>>
>> 1. macroscopically: it appears floating mass of myecilium: two
>> latyers..layer 1-close to cell surface sometimes sticking to cells..layer
>> two: surface of media..looks like oil has spilled in media..looks
>> greasy..very difficult to get rid of even after repeated PBS
>> washings..layer
>> 1: is clump of mycelia..layer 2: looks like broken mycelia floating..both
>> layer1 and layer 2 are not motile.
>>
>> 2. cell morphology does not seem to change a lot..cells look healthy.but
>> they die suddenly when the contaminant number flourishes. no change in
>> media
>> color except media top looks greasy/oily..imagine oil spilled in
>> sea!!!..they grow in FBS+pen-strep, they are resistant to geneticin too..
>>
>> 3. i took the supernatant and plated on LB agar (thats the only thing i
>> have--i dont do microbiology :))..with ampicillin (since i found out that
>> this is penicillin resistant)..within 6 days i small colonies which
>> increased up to 3 mm diameter by 15 days..all colonies have same
>> morphology..i guess hence its not something spurious..and also on two
>> different plates i got same kind of colonies.
>>
>> 4.
>> Form: Circular (grossly, but when looked at 10X magnification we can make
>> out that its not so)
>> Color: Cream
>> Margin: undulating
>> Elevation: umbonate
>> Surface: smooth. Macroscopically surface looks infrequently studdent with
>> cream colored spekles.
>> Opacity: Opaque
>>
>> 5. 40X magnification revealed very interestingly margin of this colony
>> which
>> appeared on LB plate with ampicillin had Claw like projection
>> around..covering almost entire periphery (around) of the colony..probably
>> thats how colony spreads and becomes big..also at 40X the colony does not
>> look homogenous..its made of fine grains..
>>
>> so what is it..I will try posting some pics to my blog..
>>
>> meanwhile..i really appreciate the ID..so that I can get rid of it..i am
>> anyway ordering amphotericin B.
>>
>> regards
>> sudheendra.
>>
>>
>>
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>
>


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