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strange problem# Biology - 生物学
a*y
1
支持iPhone和iPod touch了
并且支持文件夹管理文件了……
希望iOS 5下週發佈的時候
能夠更好支持設備上的文件管理
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s*x
2
i did ligation and transformation. many colonies were seen on dish. then i
picked up colonies to grow. nothing grows. i tried 3 times and the last time
i used freshly prepared LB medium. any1 teaches me what is going on? what i
should do next?? thx
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l*r
3
i like that, if I can use iphone to do presentation, that'll be a game
changer~
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s*x
4
i am sure i used the right antibiotics
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a*y
5
yes you can if you want.

【在 l*******r 的大作中提到】
: i like that, if I can use iphone to do presentation, that'll be a game
: changer~

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f*n
6
something wrong with PCR?
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s*x
7
but there are colonies on the plate with the same antibiotics.
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m*z
8
negative control for your plate? simply plate some cell to see whether they
can grow as well. this may rule out the possiblity of your LB plate being
bad...

time
i

【在 s**x 的大作中提到】
: i did ligation and transformation. many colonies were seen on dish. then i
: picked up colonies to grow. nothing grows. i tried 3 times and the last time
: i used freshly prepared LB medium. any1 teaches me what is going on? what i
: should do next?? thx

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n*w
9
you mean nothing grew... you mean after your miniprep, the product is empty?
or you mean the medium after couples of hours or overnight is still clear..
..?
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G*y
10
2nd this. First check to make sure your LB plate is still good.The selection
strength might decrease if the plates were made a while ago.

they

【在 m**z 的大作中提到】
: negative control for your plate? simply plate some cell to see whether they
: can grow as well. this may rule out the possiblity of your LB plate being
: bad...
:
: time
: i

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d*u
11
你这个问题很好解决,假设你的实验每一步都是正确的。首先,你做连接的时候,一定
有一个载体的自连对照(只有vector,没有insert),说明这不是你的载体自连。其次
你做转化的时候首先确认抗性没有问题,同时做以下几个转化:
1,载体自连对照 (应该在盘上长非常非常少)
2,insert only (应该一个都不长)
3, 你的连接产物 (如果你的实验没问题,应该长很多)
4,找一个你以前用过的没问题的相同抗性的质粒 (你可以通过计算想长多少长多少)
5,找一个你以前用过的没问题的相同抗性的质粒 (你再怎么计算也一个都不该长)
然后你就知道问题出在哪里了。
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h*s
12
It occured to me that sometime transformed bacteria grows poorly in LB broth
, but grows well in LB plate. I figured out that it was because of the
protein expressed. The solution is to shake longer or try a midprep so that
you can have enough plasmid.
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T*t
13
How did you choose your colony to pick?
How much volume of LB did you inoculate with a single colony and what type
and concentration of antibiotics are you using?
How long did you grow your LB culture? What temperature and speed?
Some general thoughts without any details regarding the above questions.
1)pour fresh LB plates, make fresh LB media
2) repeat ligation and transformation, make sure to include positive and
negative control
3) check plates to make sure you have healthy colonies and your control
plates are normal. Pick single colonies of medium size. Don't pick tiny
colonies because they might be satellite colonies. Don't pick large colonies
either because they may be overgrown. Actually do not let your plate
overgrow, if your colonies grow fast, try lower the incubation temperature
by 3-5 degrees to slow them down.
4) make sure you use exact the same antibiotic and same concentration on the
LB plates and in the liquid LB media.
5) check the temperature setting of your incubator to see if it's accurate.
make sure your culture is agitated sufficiently during incubation.
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s*s
14
有时候可能是很简单的原因,比如你接种针烧的太烫了。

time
i

【在 s**x 的大作中提到】
: i did ligation and transformation. many colonies were seen on dish. then i
: picked up colonies to grow. nothing grows. i tried 3 times and the last time
: i used freshly prepared LB medium. any1 teaches me what is going on? what i
: should do next?? thx

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T*t
15
You can use sterile pipette tips.

【在 s******s 的大作中提到】
: 有时候可能是很简单的原因,比如你接种针烧的太烫了。
:
: time
: i

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n*w
16
VWR cell spreader 我刚买。。。呵呵。。。

【在 T**********t 的大作中提到】
: You can use sterile pipette tips.
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d*u
17
我都是用玻璃珠
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s*x
18
the plates i used were made about 4 months ago. i think this is the reason.
i picked up 2 colonies and grew in lb broth without antibiotics. bacteria
grew. now i believe that the plates were not good. yesterday i repeated with
recently-made plates and there are colonies. i will grow bacteria tonight
to see what happens. thx for all suggestions.
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