bacteria streaking

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biology_06er
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bacteria streaking

Post by biology_06er » Sat Apr 28, 2007 12:52 am

Hi there

Yest in our lab we had to transfer a SINGLE colony of bacteria from one agar plate to the other--the plate that we were given was first primary streaked then with a strile toothpick a second streak was placed and then with anoterh toothpick a third streak was placed cross streaking everytime (im sure u guys no wat i mean)--now my question is it transfer a single colony so wat i did was i took a tooth pick and along the third streak that was already done, uising the toothpick i touched the streak and then streaked my agar plate...is that wat i was suppose to do??? im stressing out cos my lab partner stresses over everything so i dont wanna get my plate pack in 2 weeks time with no colonies and her make a fuss!...

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canalon
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Post by canalon » Sat Apr 28, 2007 1:38 am

Well you were supposed to touch an isolated colony to start with, but yes they are usually located in the third streak.

Although, depending on how many bacteria you had to start with and how it was done, the isolated colonies might be in the second strak, or the third streak might have contained very little cisolated colonies (too rich).

And each streak must be done with a new tooth pick, of course.
Patrick

Science has proof without any certainty. Creationists have certainty without
any proof. (Ashley Montague)

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Post by biology_06er » Sat Apr 28, 2007 3:01 am

Yep it was done with a new toothpick everytime, and the plate which we transferred them from was done by the lab technician so surely they must have done it well...so that bacteria was contained in each streak---but like you said I guess it depends on how much you had to begin with...just outta curiousty have students (or in the past) that you guys know of ever prepared a plate and then no bacteria was actually formed? (aka might not actually have transferred a colony)..just curious if it stuff like this happens all over the world?? (yeah I am weird)

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canalon
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Post by canalon » Mon Apr 30, 2007 2:04 am

I have streaked thousands of colonies (ans student working with me even more) and except in special case were viability of the bacteria was compromised (not likely in your case) I never had any problem of not enough bacteria. On the other hand, too much bacteria, and as a consequence no isolated colonies, is a distinct possibility.
Patrick

Science has proof without any certainty. Creationists have certainty without
any proof. (Ashley Montague)

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