The bacillus subtilis was storaged at -70°C. After reticle on Culture plates, I cultured them in shaker at 200rpm, 37°C for 18h. Then the culture was placed at 4°C. One week later, when I want to use this culture, I fould it become transparent. So why? Is that phage contamination?
You mean the enzyme produced by B. subtilis dissolved itself? And another question, bacteria reticle was placed at 4°C, for a few days, the color of bacterial colony turns gray. Did You ever encounter this situation?
Akos is right; perhaps it relates to resident (pro)phage, but most likely it is just outside the permissable temperature range for the mesophilic Bacillus you work with (most Bacillus strains will lyse below 5C, some need temperatures above 10-15C).
Today, I perfom gram stain, B.subtilis WB800 and the greyish colony. They are distinctly different. Then, the colony of the so cold “B.subtilis WB800” was cultured in LB without any antibiotics, It is puzzling that it seems to become the form of the “greyish colony” bacteria according to gram stain result. I guess an uncertain bacteria symbiosis with WB800. Dear Akos and Wiep Klaas Smits, did you have any idea about this? The gram stain results, as well as the greyish colony, were attached.
Morphology depends on growth conditions and strain background. There is a wide variety. If you are starting from a pure culture (this should be your first pre-requisite), you may compare the different morphologies for a single strain. WB800 is not a wild type strain too, if we are thinking of the same strain, as it is multiple protease deficient and may as a result behave differently.
Maybe, this lysis is realy a self induced process. Thank you for your advice, it’s help me a lot. Best wishes
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