Biology Stack Exchange
Biology Stack Exchange

Questions tagged [lab-techniques]

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

When asking questions on lab techniques, the following should be considered:

  • A clear outline of the experimental problem should be presented.
  • Standard names and units should be used for reagents and physical quantities.
  • If question is asking for troubleshooting, the current protocol employed should be explained stepwise.
  • The technique should be clearly important and specific to biology.
389 questions
17
votes
2 answers

What effect does vortexing have on a fluid sample that simple mechanical shaking does not?

Some protocols call for fluid samples to be mixed with a "vortexer" on the high setting. What effect does the vortexing have on fluid samples that mechanical shaking does not? Does it shear long molecules like DNA, for instance? A friend is…
Mac Cowell
  • 822
  • 1
  • 7
  • 13
15
votes
2 answers

How long will a typical bacterial strain keep in a -80°C freezer?

I know that a -80°C freezer is the recommended means of long-term cell-line storage, and that cells will typically not last long in a -20°C freezer. But how long will a typical bacterial strain (e.g., E. coli DH5-alpha) actually stay good in a…
jakebeal
  • 6,977
  • 23
  • 45
12
votes
4 answers

Are bleach solutions still routinely used in biochemistry laboratories to rid surfaces of bacteria, viruses, certain enzymes, and nucleic acids?

Decades ago I would stop by biology and biochemistry laboratories to see what was up, and I noticed a ubiquitous presence of a squirt bottle of bleach solution. When I asked what it was for I would get different answers in different laboratories.…
uhoh
  • 5,436
  • 2
  • 30
  • 77
8
votes
3 answers

Does the Petri dish lid orientation on workbench affect aseptic technique?

When examining an incubated plate, it is rather clear that holding the plate in one hand and the lid in another is best for aseptic technique, or simply resting the lid on the plate as shown below. However, I can't seem to find an answer for what…
LanceLafontaine
  • 6,705
  • 8
  • 36
  • 78
6
votes
2 answers

How long can I store autoclaved disposables and reagents?

I want to stock up on autoclaved disposables, such as Eppendorf tubes, pasteur pipettes etc., and some buffers. If I don't open the container after autoclaving, how long can I store autoclaved materials and consider them still sterile? Does it make…
Drosophila
  • 1,538
  • 1
  • 12
  • 25
4
votes
4 answers

Electronic laboratory notebook (ELN)

I have been using old style lab book for some time now but with increasing work on computer and storing sequencing results and gel pictures on computer it would be nice to have everything on computer in a form of labbook. Does any of you uses a…
MartinK
  • 338
  • 1
  • 7
3
votes
2 answers

Technical term for water entering a semipermeable membrane?

Would the word happen to be diffuse? I have tried imbibtion but that word is invalid because it isn't specific to osmosis. Research: http://www.majordifferences.com/2013/12/difference-between-osmosis-and.html#.V9xc4fkrLIU
Illa Merry
  • 31
  • 1
2
votes
0 answers

RNA product storage in isopropyl alcohol

I have an issue. I isolated RNA from cortex a few days ago. For isolation of RNA i used this procedure: I homogenizised my sample (mouse cortex) with Trizol. Then to the sample add chloroform, shooke and centrifugate it. After this part i took away…
L.Diago
  • 1,863
  • 1
  • 10
  • 26
2
votes
0 answers

Propagating errors for percentage reduction

Need a bit of help for this particular problem. I have three averages collected from three genotypes (A, B, and C) and their associated SD (a, b, and c). A is my control. I have been asked to represent the data as a percentage reduction as compared…
user8151770
  • 21
  • 1
2
votes
3 answers

Is RNase AWAY in the lab dangerous?

I use RNase AWAY in the lab. I would like to know how dangerous this chemical is for health. For example, when I remove my gloves my hands smell because of the RNAse AWAY
user17471
  • 21
  • 1
  • 2
2
votes
1 answer

Pippin prep kits - expiration date

Do you use Pippin prep? We would like to buy it, but we need more info. What is the expiration date of kits for Pippin prep? Thanks!
tatiana.aghova
  • 159
  • 6
1
vote
1 answer

Why spin live fruit flies in centrifuge?

I was reading this article about the evolution of monarch butterflies’ resistance to cardiac glycosides: These Butterflies Evolved to Eat Poison. How Could That Have Happened? And this passage made me curious: The researchers put the mutant flies…
Kal
  • 1,328
  • 1
  • 8
  • 18
1
vote
1 answer

DNA gel extraction: chemical contaminants

I am performing a gel extraction to purify DNA after a double digest with EcoRI and BamHI. After the gel extraction I need to complete a ligation step before bacterial transformation. The problem I am having is that the DNA after the gel…
Kevin
  • 429
  • 2
  • 15
0
votes
0 answers

qPCR to detect viral load

In an experiment qPCR was used to determine viral load. Alongside this conventional PCR was also performed and ran on an agarose gel. However I do not understand why both methods would have been used, any insight would be greatly appreciated?
Beth
  • 9
  • 2
0
votes
1 answer

How well do Eppendorf cups seal?

I am considering to send some samples overseas in Eppendorf cups. They are the standard plastic cups of 1 to 2 mL capacity. Of course they may tip over during their journey and I'd like to know how well they seal or if there is any danger that…
Stockfisch
  • 147
  • 13