Why resistant strains can t be grown on non resistant plates

The reasons why resistant strains cannot grow on non-resistant plates are:

1.Antibiotic-free plates refer to a medium that does not contain any antibiotics, whereas a resistant strain is a strain that has antibiotic-resistant properties, they can grow on a medium containing antibiotics but not on a medium that does not contain antibiotics.

2.Antibiotic-free plates are primarily used to screen for target genes or proteins, while resistant strains are screened in an environment that contains specific antibiotics.

3.Microorganisms grown on antibiotic-free plates lack the appropriate metabolic pathways or enzymes, are unable to utilize specific substrates or growth factors, or lack other necessary factors.

In conclusion, resistant strains cannot grow on antibiotic-free plates because they need to be grown on a medium containing specific antibiotics, and the corresponding growth conditions are lacking on antibiotic-free plates.

Resistance is on your plasmid, the strain is non-resistant, and the strain needs to be transferred into a resistant plasmid to grow on the plate.

Do multiple plasmid transformations that don't grow out, you see, are these three problems:

Is there a mistake with resistance? Some are kan, some are amp, see if you have the wrong board.

Has the transformed plasmid been degraded, or the plasmid is not good, or is there a problem with the transformation operation.

It is not a competent cell.

The conversion efficiency is too low, you can detect it.

There are too many miscellaneous bacteria, and the growth rate is faster than the strain you need, so the coating needs to be screened with antibiotics.

If the resistant plate is prepared without any problems, and the test steps such as inoculation are normal, it indicates that the plasmid has not been transferred to the host bacteria.

WOKE2008 (contact ta) If it is a non-antibiotic LB liquid medium, it will not be a problem of operation or medium for a long time (the non-antibiotic will be contaminated if you are not careful, not to mention the bacteria); If it's resistant, it's because the monoclonal on your plate is a miscellaneous bacterium, and it won't last long when you switch to the resistant liquid medium! Yinleidawn (contact ta) No.,I've turned it around several times.,There's no problem with the medium.,Because there's no transformed bacteria to grow.。。 If the plate is a miscellaneous fungus, the colony morphology looks like E. coli, no problem, silicare, ampicin is easy to fail after a long time, and the ampicillin-resistant E. coli will also decompose the ampicillin, so you should use a freshly transformed plate to pick bacteria, avoid picking satellite colonies wwllkkhh (station contact ta) Do not pick the small plaques around the colony (pick the center of the colony), ampicin will lose its resistance after a long time, it is recommended to pick the bacteria early.

I've had this issue as well, and there are two scenarios.

1. If it appears after transformation, it depends on the number of colonies grown after transformation. If the plate is densely packed with colonies, it may be that ampicin has failed or partially failed (after all, it is necessary to pour the plate while the medium is not set, and the temperature may be a little higher when ampicin is added; Or maybe the tablet has been stored for too long). If there are only a few colonies sporadically growing on the plate, it can be considered as miscellaneous bacteria or inactive transformants.

Personally, I think that the environment of solid ampicin medium is much better than that of liquid ampicin medium, which is why the bacteria that have been frozen for a long time will be plated and activated first.

At this time, it is recommended to re-invert the tablet or re-do the connection conversion.

2. I have also encountered the situation that the screened target bacteria are frozen in the refrigerator for too long, and grow on the plate when they are resurrected, but they reproduce extremely slowly in the liquid medium, and they are basically not long.

Later, I solved this problem by re-transferring into competent cells with the saved plasmid.

Hope the above helps. I think it's important to find the cause in an experiment, but sometimes it's better to do it all over again. Because, many unsuccessful results are caused by accidental factors.

First, is there a problem in determining the resistance of the proposed medium? (The resistance is wrong, it can't grow) and then, after the alcohol lamp of the inoculation ring is heated and sterilized, is it not enough to cool down before taking samples for inoculation? (scalded, ironclad colony).

Then, is the sample contaminated with bacteriophages? (Bacteriophages cause bacteria to die) good luck.

Are plate and liquid media resistant? Having trouble with inoculation? Mismatched liquid media? What bacteria? What medium?

Is there a problem with the inoculation operation?

The description is not detailed, presumably it is the problem of oxygen**--