Questions relating to protocols, procedures, and good practice when using laboratory equipment.

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12
votes
2answers
638 views

How sterile is sterile when working with nucleic acids to prevent contamination?

I am reading up on preparatory work on working with nucleic acids and a lot of the instructions speak on excessive procedures on cleaning environments with high %ethanol and making sure the equipment ...
4
votes
1answer
8k views

NaCl role in CTAB - DNA complex in DNA extraction

I have a question about the role of NaCl in the DNA extraction process. So for NaCl concentrations under 0.5M, CTAB and DNA molecules can create complexes. In those concentrations, proteins and other ...
6
votes
2answers
1k views

Alternatives to trypsin for cell detachment?

I have ran out of trypsin and need to passage my cells (immortalized chondrocytes, C28/I2) today or tomorrow. I have been out of town and forgot to order more trypsin. I was wondering if there are ...
2
votes
2answers
442 views

Using an analytical balance (0.0000 precision) to measure µg (micrograms)?

If i needed to prepare 200µg/ml of proteinase K, and the proteinase K was in a solid powder form, would I have to weight out 200 µg using an analytical balance, and if so, is it possible with a ...
4
votes
2answers
97 views

Short, concise, practical manual for doing experimental biology

I am am physical scientist working in biology, and have recently started doing experiments. I would like a manual akin to "Numerical Recipes", but for the lab: straight forward, easy instructions on ...
19
votes
3answers
2k views

How long can I store extracted RNA?

If I extract RNA from a (leaf tissue) sample using a one-step phenol:chloroform extraction, how long can those samples be stored at -80°C? And how many times can I defrost and refreeze them before ...
6
votes
1answer
485 views

Alternatives to CFU plating for measuring number of viable cells?

I am hoping to measure growth rates of a bacterial culture in several growth conditions. I am concerned that these growth conditions may cause cell death, which would lead to a decreased ...
3
votes
2answers
72 views

What is an Ihh-/- mouse?

This one is too basic question: I just came across $Ihh^{-/-}\ $ mouse. Is that means this mouse devoid of that gene Ihh. What is this sign called and are there other such representations?
13
votes
2answers
742 views

Are there issues with filling PCR tubes to capacity?

I'm planning to scale up a PCR reaction, and I'm wondering if filling the PCR tubes to the maximum volume of 200 ul would be a problem. It would mean a lot less pipetting as I would only need 1/4 of ...
6
votes
2answers
412 views

introduction to Chip Seq

I hope this question is suitable for this site. I am concerned about the Chip experiment part so I think it should be okay. I am a Applied Math student starting to get into bioinformatics and so I've ...
4
votes
1answer
84 views

How sterile is working next to a bunsen burner?

When I was still doing lab work, many people would just wear gloves and work next to a bunsen burner because the clean benches were all in use. This was mostly for plating bacteria like Bacillus ...
3
votes
1answer
63 views

How C. Elegans is used for siliencing genes

The experiment that is using C. Elegans to silence the Genes. I have a question about Why and how C. Elegans can use the DNA plasmid that is generated with the gene of interest in the bacteria by ...
3
votes
1answer
937 views

Optogenetics - How do microbial opsins work?

I'm just introduced to the optogenetics method and am having some trouble grasping the genetics (of the optogenteics) part of things. So we have Retinal and Opsin that form Rhodopsin molecule that ...
2
votes
2answers
136 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 ...
-1
votes
1answer
918 views

How to make µg/ml concentrations of proteinase-K?

How does one prepare concentrations in the mass/volume (weight/volume) form, for substances like nucleic acids or in this case, proteinase? A detailed example would be helpful. I need to prepare ...