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How delete survival gene in bacteria still keeping cell alive. - (Aug/02/2012 )

How delete survival gene in bacteria still keeping cell alive. How we can know given gene is essential for survival ?

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Put simply, you can't. If a gene is essential to survival, then the bacteria simply can't survive without it.

(unless, in some cases, you want to supplement that gene product from elsewhere, e.g. a plasmid or in the media itself).

-leelee-

Thanks for reply. How one is supposed to know that given gene is essential for survival? trying deleting gene probably will not give colony. what if survival gene product could not be supplied from outside media.

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prabhubct on Fri Aug 3 14:21:04 2012 said:


Thanks for reply. How one is supposed to know that given gene is essential for survival? trying deleting gene probably will not give colony. what if survival gene product could not be supplied from outside media.

Well if you delete 1 gene and the bacteria dont survive ... then you kno its a gene essential for survival.

And what do you mean by "what is survival gene product could not be supplied from outside media" ?
Are you talking about "food" that bacteria need to survive ?

-pito-

How can we select bacterial mutant on growth medium if survival gene is deleted. merely no colony to judge as gene is essential for growth may not be effective. Reason for no colony might be errors in experiment or homologous recombination problem.

what if survival product is not food but some internal machinery of bacteria say DNA polymerase which could not be supplied from outside.

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prabhubct on Fri Aug 3 15:28:13 2012 said:


How can we select bacterial mutant on growth medium if survival gene is deleted. merely no colony to judge as gene is essential for growth may not be effective. Reason for no colony might be errors in experiment or homologous recombination problem.

what if survival product is not food but some internal machinery of bacteria say DNA polymerase which could not be supplied from outside.

You are right.

The problem with deleting or mutating an essential gene does indeed imply that the bacterium wont grow...
See the attachement on how researchers look for essential genes.
And check this: http://www.nature.com/srep/2011/111020/srep00125/full/srep00125.html#/f2, check figure 1!

Also: to make sure its not because of the medium, you use the same medium as when the gene was not distrupted.

And about the internal machinery of bacteria not be supplied from outside: not sure what you mean by this... If it can not be supplied from outside when you altered the gene.. it will also not be supplied from outside without altering the gene (unless its a gene for a transporter that brings in , for example, a certain nutrient... but then again: it means that the gene you changed is essential for survival).
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-pito-