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why sometimes big or small colonies? - (Jun/27/2009 )

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my colonies on agar plates are sometimes small and very close to each other, or sometimes big and separate?

why does this happen? I'm using TOP10 and incubate 16-18 h at 37 C. It's very hard to pick small colonies.

-Curtis-

I do get big and small colonies at times. And I believe it is due to how you spread your dilution on the plates. But it is okay. It is very simply to pick small colonies. Here is one trick. Buy some toothpicks and place them in a beaker. Cover it with aluminium and send it for autoclaving. AFter that, you can always pick your tiny colonies with the toothpick and drink the toothpick into your culture tube containing LB broth and the appropriate antibiotics!

-jiajia1987-

jiajia1987 on Jun 29 2009, 12:07 PM said:

I do get big and small colonies at times. And I believe it is due to how you spread your dilution on the plates. But it is okay. It is very simply to pick small colonies. Here is one trick. Buy some toothpicks and place them in a beaker. Cover it with aluminium and send it for autoclaving. AFter that, you can always pick your tiny colonies with the toothpick and drink the toothpick into your culture tube containing LB broth and the appropriate antibiotics!


When you do that, remember to get cheap toothpicks. The more expensive brands are often impregnated with disinfectants... not goo if you're wanting to keep the bugs alive!! :(

-swanny-

swanny on Jul 3 2009, 12:47 PM said:

jiajia1987 on Jun 29 2009, 12:07 PM said:

I do get big and small colonies at times. And I believe it is due to how you spread your dilution on the plates. But it is okay. It is very simply to pick small colonies. Here is one trick. Buy some toothpicks and place them in a beaker. Cover it with aluminium and send it for autoclaving. AFter that, you can always pick your tiny colonies with the toothpick and drink the toothpick into your culture tube containing LB broth and the appropriate antibiotics!


When you do that, remember to get cheap toothpicks. The more expensive brands are often impregnated with disinfectants... not goo if you're wanting to keep the bugs alive!! :(


Good one!

-jiajia1987-

jiajia1987 on Jul 3 2009, 12:31 AM said:

swanny on Jul 3 2009, 12:47 PM said:

jiajia1987 on Jun 29 2009, 12:07 PM said:

I do get big and small colonies at times. And I believe it is due to how you spread your dilution on the plates. But it is okay. It is very simply to pick small colonies. Here is one trick. Buy some toothpicks and place them in a beaker. Cover it with aluminium and send it for autoclaving. AFter that, you can always pick your tiny colonies with the toothpick and drink the toothpick into your culture tube containing LB broth and the appropriate antibiotics!


When you do that, remember to get cheap toothpicks. The more expensive brands are often impregnated with disinfectants... not goo if you're wanting to keep the bugs alive!! :(


Good one!



has nothing to do with how you spread your cells...and everything to do with plasmid copy number and the insert (size, complexity, etc.).

think about it.

cells with fewer plasmid copies will grow slower when challenged with same concentration of antibiotic over cells with a very high number of copies...toxicity of insert will affect growth in the same manner, and longer inserts take a little longer to replicate.

I do not know what TOP10 means or stands for, I suppose its the way how you spread your dilution on the plates?


how can you not know what TOP10 is? if you don't know something, don't offer bunk advice or at least look it up. good luck with that.

-eldon-

lol @ eldon

thank you!

-Curtis-

eldon on Jul 3 2009, 03:05 PM said:

how can you not know what TOP10 is? if you don't know something, don't offer bunk advice or at least look it up. good luck with that.



ooooooohhhh - angry :(

;) d

-Dominic-

Curtis on Jun 28 2009, 07:30 AM said:

my colonies on agar plates are sometimes small and very close to each other, or sometimes big and separate?

why does this happen? I'm using TOP10 and incubate 16-18 h at 37 C. It's very hard to pick small colonies.

Iīm sure the answer is very simple. Not due to copy number or anything else "fancy". You describe small colonies when they are close together and large well isolate ones.

Colonies close together compete for nutrients and poison each other with their waste products. Hence slow growing bugs and small colonies. Well isolated colonies donīt have this problem (lots of space to grow, plenty of food and a large area for waste to diffuse away from colony.

-klinmed-

how can you not know what TOP10 is? if you don't know something, don't offer bunk advice or at least look it up. good luck with that.



I don't think the person means that he don't know what TOP10 cells are. I guess he/she doesnt know what TOP10 stands for; what the abbreviation is. Don't scare him/her off like this!!

-jiajia1987-

Colonies close together compete for nutrients and poison each other with their waste products. Hence slow growing bugs and small colonies. Well isolated colonies donīt have this problem (lots of space to grow, plenty of food and a large area for waste to diffuse away from colony.


So explain a bacterial lawn of growth. Nutrients on an LB plate are in excess and can support a lawn of bacteria for up to a month or longer.

-eldon-
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