http://www.protocol-online.org/forums/index.php Fri, 20 Nov 2009 16:05:19 -0800 360 http://www.protocol-online.org/forums/index.php?showtopic=11675
it sounds bizarre to me somehow! it could not be much??! are there some values?

what is meant, when plastic is declared as pyrogenfree - is it the procedure of production?

thx]]> Thu, 19 Nov 2009 09:38:39 -0800 http://www.protocol-online.org/forums/index.php?showtopic=11675 http://www.protocol-online.org/forums/index.php?showtopic=11673
Thanks]]> Thu, 19 Nov 2009 09:21:37 -0800 http://www.protocol-online.org/forums/index.php?showtopic=11673 http://www.protocol-online.org/forums/index.php?showtopic=11659
I'm sure the recipe is ok, as most of other protocol available online also suggested the same. The only modification I made is I used 1.14g Na2HPO4 anhydrous instead of the one suggested (not in anhydrous form).

Could the anhydrous form cause the problem? Is there anyway to solve it?

I compared my recipe with other labmates, and found out that they used NaH2PO4 instead of Na2HPO4. I am thinking if I can use their protocol, then adjust Na+ ion concentration using NaOH? Assuming the pH will be quite alkaline, then I will just adjust the pH back to 7.4 with HCl. Is that ok?]]> Wed, 18 Nov 2009 18:26:22 -0800 http://www.protocol-online.org/forums/index.php?showtopic=11659 http://www.protocol-online.org/forums/index.php?showtopic=11654

Thank you.

Mike]]> Wed, 18 Nov 2009 14:32:15 -0800 http://www.protocol-online.org/forums/index.php?showtopic=11654 http://www.protocol-online.org/forums/index.php?showtopic=11643 Does anybody know of a way to measure phenol red concentration?
Thanks]]> Wed, 18 Nov 2009 06:00:27 -0800 http://www.protocol-online.org/forums/index.php?showtopic=11643 http://www.protocol-online.org/forums/index.php?showtopic=11632 any tricks to remove an old histology slide cover slip for re-staining ? Tue, 17 Nov 2009 23:59:35 -0800 http://www.protocol-online.org/forums/index.php?showtopic=11632 http://www.protocol-online.org/forums/index.php?showtopic=11622
I need to make sure my silanized glass tubes are DNA free. What can I do? Cross-linker? I'm not sure I could use bleach. What do you think?
I just need DNA free tubes where DNA won't bind to the tube.

Thanks for your help.

Maddie]]> Tue, 17 Nov 2009 15:55:12 -0800 http://www.protocol-online.org/forums/index.php?showtopic=11622 http://www.protocol-online.org/forums/index.php?showtopic=11617
First sorry if it's not the proper place to post this but I didn't know where to put it so...
My question is, when you send samples to sequence, they always ask for the kind of vector you used. Why?
I mean, I'm sending them my plasmid, and the primers so why do they need to know what kind of vector I used?

I'm asking because one of the student made a mistake and didn't write down the right vector. So is it really important? Does she absolutely need to change it or should it be ok?

thanks]]> Tue, 17 Nov 2009 12:47:55 -0800 http://www.protocol-online.org/forums/index.php?showtopic=11617 http://www.protocol-online.org/forums/index.php?showtopic=11603 can I measure protein concentration from RIPA lysate using NanoDrop reader at 280nm instead of standard methods such as BCA or Lowry, I compared BCA with this ones and results were quite different, let say 10 times higher in case of NanoDrop???? Tue, 17 Nov 2009 03:56:13 -0800 http://www.protocol-online.org/forums/index.php?showtopic=11603 http://www.protocol-online.org/forums/index.php?showtopic=11602 Tue, 17 Nov 2009 02:32:39 -0800 http://www.protocol-online.org/forums/index.php?showtopic=11602 http://www.protocol-online.org/forums/index.php?showtopic=11594 how does everyone collect serum from blood.I used the BD microtainer serum separator tubes to collect the serum from mice,but after doing the electrophoresis there seems to be fibrinogen in it.i take the blood from the mice using capillary tubes and then flush it into the SStubes.i allow the tubes to stand for more than an hour before doing the centrifuge.i then aspirate the serum that usually stands above the gel.
Thanks]]> Mon, 16 Nov 2009 19:34:00 -0800 http://www.protocol-online.org/forums/index.php?showtopic=11594 http://www.protocol-online.org/forums/index.php?showtopic=11588
I prepare my own sterile water for PCR reactions. Every few months. I autoclave ~50 x 1.5 mL eppendorf tubes, each with 1 mL of water inside. The tubes are clean and the water has come from a filtered water source in our lab. When I autoclave, I cover the tops of the tubes to prevent them bursting open. The eppendorf's are then stored in a screw top jar on my bench.

However, every time, after a month or so, I start to see small flecks of white appear in the water. Before I ignored it, knowing that they were still sterile, but as I've been having trouble with contamination recently, I started to suspect this might be the source. But when I look at these specs under the scope, I do not see any cells. I'm thinking of calling the manufacturer of the tubes to ask them for their advice, but I thought I'd post here first.

Any thoughts?

Cheers,
Phil]]> Mon, 16 Nov 2009 17:22:35 -0800 http://www.protocol-online.org/forums/index.php?showtopic=11588 http://www.protocol-online.org/forums/index.php?showtopic=11566 how do i theoratically determine the extinction co-efficient for a glycoprotein??!! is it even possible? the extinction will be of the native proteins and even sites like the expacy will give me extinction related to native protein without the PTM's but to find conc, i cant use this as even the glycans will contribute to the absorbance readings!! they do!!
Any suggestions?
Any easy approach for measuring it in the lab with limited resources??!!!
Any literature??
Thankx!!!]]> Mon, 16 Nov 2009 01:44:23 -0800 http://www.protocol-online.org/forums/index.php?showtopic=11566 http://www.protocol-online.org/forums/index.php?showtopic=11556
(I allready have MPN table for 10-fold dilution and 3 or 5 tubes per dilution)

Thank you
Apostolos Patsias
apostolospatsias@yahoo.gr
]]> Sun, 15 Nov 2009 09:33:42 -0800 http://www.protocol-online.org/forums/index.php?showtopic=11556 http://www.protocol-online.org/forums/index.php?showtopic=11553
I've found that NCI commonly uses GI50 to calculate the anticancer potential of new drugs. Since now, I've calculated the IC50 of a drug after a 3 days exposure of cancer cell lines to the compound at different concentration, simply calculating : "number of cells in treated well/number of cells in control well" . It is obvious that in cancer cell lines that have a faster growth you will find lower IC50, so it would be better to have another parameter, possibly less influenced by this. Does GI50 answer to these questions? How to calculate ?

Thanks]]> Sun, 15 Nov 2009 05:54:43 -0800 http://www.protocol-online.org/forums/index.php?showtopic=11553 http://www.protocol-online.org/forums/index.php?showtopic=11540
I have the following question: I received a protocol both blottings methodes.
And for the northern blotting one step is to use formamide to prevent or reduce intermolecular basepairing.
Now I am wondering: why do I need to do this only when using northern blotting? And not with southern blotting? Is this because DNA has less intermolecular basepairing?

Or is this just an error in 1 protocol and should I do it in both protocols? Or is it ok just to do the formamide step only when working with RNA (northern) and not when working with DNA (southern)?

thanks]]> Sat, 14 Nov 2009 07:33:13 -0800 http://www.protocol-online.org/forums/index.php?showtopic=11540 http://www.protocol-online.org/forums/index.php?showtopic=11508
I have a gene in PCR4-TOPO vector. It has got T3 and T7 promoter. Are these mammalian promoters? I wanted to transfect but am not sure if this is an expression vector. The manual dosent say anything about it. Also it has a LacZ operon. Whats the use of it?

pls pardon my naivity.

Thanks]]> Fri, 13 Nov 2009 02:32:11 -0800 http://www.protocol-online.org/forums/index.php?showtopic=11508 http://www.protocol-online.org/forums/index.php?showtopic=11491
any idea why? is because it's in non reducing condition?

beta actin is it better?
]]> Thu, 12 Nov 2009 09:40:22 -0800 http://www.protocol-online.org/forums/index.php?showtopic=11491 http://www.protocol-online.org/forums/index.php?showtopic=11478
To start i have some cells with a concentration of 9.7 x107/ml.
I took 2ml of these cells and added 1ml of media to them.
What is the concentration?

If i then take iml of the above diluted cells and add a further 0.5ml of media what is the concentration of these cells now?


jay
]]> Wed, 11 Nov 2009 18:35:54 -0800 http://www.protocol-online.org/forums/index.php?showtopic=11478 http://www.protocol-online.org/forums/index.php?showtopic=11448
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