Last week, I did quadrant streak to get a single colony of my bacterial culture. But it turns out to be like this if I see them in under the microscope. The original bacteria that i streak has wavy circular morphology, but the result of quadrant streak doesn't show the same morphology, instead it shows like yeast hifa. Did that truly a contamination? So, is there no any solution for this?
The pictures look to me like a mucoid mutant of E. coli. Obviously I can not be certain from only a picture but that would be my best guess.
That sort of growth pattern indicates that your bacteria is motile. Some bacterial species like alphaproteobacteria can show this transition when grown on plates with a lower salt concentration than LB (one of the reasons why LB is formulated the way it is). Another cause can be quorum sensing or nutrient depletion which can be a side effect of your larger culture. If you think it is contamination take a smear and do some serial dilutions in distilled water and plate out before picking individual colonies.
Thank you for the answers,
I did the quadrant test again on the other original colony to make sure that they're contaminated or not
My professor afraid that those structure turns out to be contamination
And yes we guess it is.
Cause the results of seconds streak is pretty good, clean, and similar to original colony
So we did use the second streak, here is the result:
If this bacterial strain may be important for your research, you may want to do an assay for antibiotic resistances that you can use for selection in future.
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