Hello,

E. coli TG1 is a laboratory strain of the bacteria Escherichia coli. Under normal growth conditions, E. coli cells are rod-shaped, typically about 1-2 micrometers in length and 0.5 micrometers in width.

However, as you mention, if you see big rods under the microscope and you think that you might have contamination, it may not be E. coli TG1. If a bacteria is grown under suboptimal conditions, it can change the shape of the cells, so it's possible that you are observing a different type of bacteria. Another thing to consider is that the strain you have is an engineered one and it may have differences in the morphology compared to a wild type E.coli.

It's possible that the morphology you are observing is caused by a contaminating microbe, such as a rod-shaped bacteria other than E.coli. It is important to perform further experiments to confirm the identity of the cells you are observing. For this reason, you should consider performing additional tests such as Gram staining, PCR to confirm the strain you are working on, or running cultures on selective and differential media that will help you identify the specific microbe. Please let me know if there's anything else I can help you with.

Regards.

Hi,

Do you have pictures of what you saw under the microscope? The chance of contamination always exists...

Thanks for your help.

I compared my cells with another bacteria stock from another lab, and it seems that E. Coli could have also a rod shape, especially under stress conditions.

TG1 cells are permissive cells and so I used them for the infection with phages. I can consider it a stress condition and in fact I can see a rod shape under the microscope.