What are Feeder Colonies? - Basic Question (Aug/13/2006 )
Hello guys,
What exactly are feeder colonies? What causes (scientific cause) them to grow in plates?Are there other terms for these?What is the best way to avoid having them?
Thank you so much..
some cell types need to have some cell contact or some growth factors produced by other cells to grow, e.g. lymphocytes.
Or some time you want to clone some cells, and you can't just put one cell in a well. If you dilute too much the cells, they won't grow, because the few growth factors, cytokine... produced by the cell and necessary to their growth will be too much diluted. Therefore you have to add feeder cells. It's cells that were either treated with mytomycin or irradiated to kill them so the only cell that will grow is your clone. They will help the cells until these cells are numerous enough.
yeeh, in other words, they support the growth of cloned cells by their growth factors diffused from their membranes (feed your cells)..
how is this applied in the case of bacterial cells harboring an antibiotic resistance gene? growing on plates with antibiotic.
I've no idea.
no confusion with satellite colonies?
I think you are confused with satellite colonies.
This happens when you plate the transformation product on the antibiotic containing agar.
When you culture antibiotic resistant bacteria on an agar containing the antibiotic, the resistant bacteria will degrade the antibiotic. If you let the culture too long in the incubator, some bacteria that didn't incorporate the plasmid, and therefor are not resistant to antibiotic, start to grow, because the antibiotic is degraded by the resisitant bacteria. these colonies look smaller than the resistant colonies, and grow beside the resistant colony. They are called satellite colonies.
To avoid them, you should not let your bacteria grow too long. 16 hours is enough.
This happens when you plate the transformation product on the antibiotic containing agar.
When you culture antibiotic resistant bacteria on an agar containing the antibiotic, the resistant bacteria will degrade the antibiotic. If you let the culture too long in the incubator, some bacteria that didn't incorporate the plasmid, and therefor are not resistant to antibiotic, start to grow, because the antibiotic is degraded by the resisitant bacteria. these colonies look smaller than the resistant colonies, and grow beside the resistant colony. They are called satellite colonies.
To avoid them, you should not let your bacteria grow too long. 16 hours is enough.
ah ok.thanks. thats exactly what im referring to
. i came across this journal that mention "feeder colonies". But it was mentioned in the protocol as" All kanamycin resistant colonies that appear will be transferred to fresh kanamycin plates to ensure that they are not feeder colonies"
thats y i wonder what that is:) anyway ur explanation is very very clear. Thank u so much missele.and ill put that into mind. Thanks again
Ah OK, it's the first time I hear about feeder colonies for bacteria.
I'm glad I answered your question.
Or some time you want to clone some cells, and you can't just put one cell in a well. If you dilute too much the cells, they won't grow, because the few growth factors, cytokine... produced by the cell and necessary to their growth will be too much diluted. Therefore you have to add feeder cells. It's cells that were either treated with mytomycin or irradiated to kill them so the only cell that will grow is your clone. They will help the cells until these cells are numerous enough.
i'll be growing normal mouse fibroblasts 2 cells/well. what type of feeder cells do i need? can I use any type of cells? can you send me some protocols to prepare these feeder cells (other than irradiation)?
is it possible to clone antibiotic-resistant feeder cells!!? just a wonder
