I seeded two flasks (T-12.5) in two different CO2 incubators. They contained the same number of cells, the same media, etc. The one-seeded in the rarely used incubator had an abnormal morphology ( the cell had more extension like pseudopodia), and after 2-3 days, the media had changed to entirely yellow. )
Please have a look at this.
Is this due to contamination? If so, why the change in cell morphology? What kind of contamination?
Was there any funny smell of the media? If pH changes relatively fast, that could suggest bacterial growth. Do you see any yellowish sludge in media stocks left in the fridge? I've had colleagues literally grow buckets of bacteria in DMEM medium without realizing it had been contaminated.
Yes, the media, too, had turned yellow after 2 days. At the same time, the one in the other incubator remained the same Can Kiessling
When you say "Yes, the media, too..." do you mean the media smells funny? Did you take a look at the medium, did it turbid? Have a look at this (the first picture gives an idea of what I'm talking about):
https://handling-solutions.eppendorf.com/cell-handling/contamination/scientific-background/bacterial-contamination/
I don't think you can get a fast pH change if you just had cells grown unless you left them there for a few days without media change.
No Can Kiessling there wasn't any funny smell or turbidity. After one day, it was slightly yellow. The next day evening it was completely yellow with unusual cell morphology.
Well if you are suspicious of contamination, you should just chuck it away if you have other flasks. When I was suspicious of contamination, I would just chuck away the flask and move on. It is an eventuality to get your cell culture contaminated (having grown cells for 5 years in a lab). I would move on with the flasks that seem OK, note it down in my lab notebook and don't think too much of it unless it becomes chronic. If it becomes chronic, then you know something is up.
The CO2 regulator of the seldom - used incubator may be out of calibration. Too much CO2 would turn the medium acid/yellow and affect the cytoskeleton/morphology. One example: Article Immobilized pH in culture reveals an optimal condition for s...
Thank you very much Ellen A G Chernoff
The CO2 level was at 5%. But I guess you may be correct. Cause the incubator earlier had similar problems related to CO2 release.
In partial answer to your question about how low pH affects the cell shape: pH affects integrin binding and signals transmitted to the actin cytoskeleton through the Rho GTPase system
Article Acidic pHe regulates cytoskeletal dynamics through conformat...
Thank you very much for your help Ellen A G Chernoff
This is intriguing.
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