Chemicals used in the lab for experiments.

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6
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3answers
215 views

Is NADPH salt still usable after an hour at room temperature?

I accidentally left a delivery of NADPH Tetrasodium Salt (Santa Cruz Biotechnology) at room temperature for a little over half an hour. In addition, when I opened up the package, I briefly held the ...
2
votes
2answers
91 views

Why do many DNA solutions contain additional compounds?

DNA solubility data in only water is scarce. A previous question asked for a quantification of DNA solubility in water. It seemed like it would be easily answerable, however isn't quite that simple ...
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3answers
103 views

Trypsin and cell culture

I am doing an experiment where I have treat the cells with a drug and calculate their counts. I would like to know if is bad to trypsinize the cells in consecutive days i.e. twice within 48 hours. How ...
5
votes
1answer
46 views

Is there a protocol for freezing and thawing Bacillus subtilis cells?

There is a book that says to store Bacillus spores in 50% glycerol at -70 degrees Celsius (doesn't mention if the 50% is final concentration or not). But from what I know, the cells themselves can be ...
1
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2answers
66 views

How to safely sterilize urea-containing growth medium?

I'm using urea-containing growth medium for experiments with bacteria (1-2 l/day). After the experiment, the growth medium has to be sterilized and disposed. I did this so far by autoclaving, but our ...
1
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1answer
74 views

What is Trypsin? [closed]

I am currently helping a PhD student in his research lab. We have been using Trypsin for the past couple of weeks but I am unsure of its purpose. I was wondering how Trypsin functioned and what it was ...
2
votes
3answers
548 views

Long term storage of agarose-ethidium bromide gels that have already been cast

I have come up with what I thought was a clever idea: Store the agarose gels I pour, and only cut as many lanes as I need to run later, minimizing wasted agarose (and wasted effort/time) when I need ...
3
votes
1answer
94 views

PCR master mix contents

I am running PCR reactions with different sets of degenerate primers and I want to know what should go into the master mix My usual master mix: DEPC water PCR buffer (-Mg) 25mM MgCl2 10mM ...
2
votes
1answer
133 views

Substitute 25mM dNTPs mix with 10mM dNTPs

I need to make a solution of multiple compounds, one of them is dNTPs. The recipe calls for 20 μl 25 mM dNTPs in a 1250 μL master mix. Unfortunately I do not have it available at that concentration, ...
3
votes
2answers
934 views

Just how light-sensitive is ethidium bromide?

One lab I was in was paranoid about keeping it in a foil-wrapped conical tube; my current lab leaves it out on the bench (and it works fine for staining gels). It's the same company/concentration in ...
3
votes
1answer
159 views

How do different tissue culture matrices affect background in fluorescent microscopy?

In response to my previous question, I've been reading up a little bit on poly-D-lysine, Collagen I, Collagen IV, laminin, and other tissue culture coatings that promote cell adhesion. I've always ...
3
votes
1answer
214 views

What is the best way to clean plastic flasks that have been used for cell cultures - is virkon a good idea?

When you use cultures e.g. insect cells, which are infected with virus one way to clean the (plastics) shake flasks is with virkon. Which is the most effective way to clean your flasks in order to ...
5
votes
2answers
2k views

Is wiping with RNAse Zap enough to destroy RNAse activity?

From the RNAseZap MSDS, it is an SDS at some unknown concentration, maybe with some NaOH? Some other links suggest there is some NaOH as well. The Ambion site states that RNAseZap destroys RNAse ...
4
votes
1answer
307 views

Can I heat Trizol?

I wonder if I can heat Trizol reagent for 30 min 65C. The goal is to disrupt protein-RNA complex while inhibiting nucleases. (I can't use RNasin cause it's inactivated in 65C, and can't use RVC cause ...
8
votes
2answers
10k views

Agarose vs agar? Why do DNA gels use agarose only and how do you obtain agarose from agar?

Agar is a relatively cheap substance from red algae. And it contains a saccharide agarose as well as a small amount of pectin. Agar is used for culture plates as is, but for DNA gels a grade of ...
4
votes
1answer
255 views

Is DNA green viewer carcinogenic?

I use DNA green viewer in Lab to see DNA and RNA bands. Some peers told me it is carcinogenic and is not safe. Is this correct? If yes, are there better choices to use in working with gel?
5
votes
1answer
185 views

What is the extent of the effect of Tris on E. coli?

I was a fool and dissolved my antibiotic (Kanamycin) into Tris Buffer rather than H₂O. The Kanamycin still seems to be active but a fellow labmate mentioned that Tris messes around with the membrane ...
5
votes
1answer
548 views

What are good practices with reusing desalting columns

At least according to a few sources Prozyme and Protocols-Online, it is possible to reuse desalting columns and since I'm cheap I would like to also. Key things seem to be washing with several column ...
7
votes
2answers
298 views

What are key factors when evaluating and comparing miniprep columns?

I'm looking to comparing different protocols for minipreps for plasmid DNA purification. What factors should I be looking at? A few things come to mind: Cost Yield Time per step Replacement with ...