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9 votes
Accepted

"X" in stock solutions

1x is the final working concentration of the solution (it could be anything depending on the type of the solution). Stock solutions are made at a higher concentration; if it is 10 times more ...
WYSIWYG's user avatar
  • 35.6k
9 votes

Alternative dyes for Gram staining

As you may have realized, crystal violet can be replaced by a lot of dyes since the ethanol will wash out the dye from the gram negative cells. Methylene blue is a nice choice - malachite green may ...
Traci's user avatar
  • 201
6 votes
Accepted

1% water solution of deoxycholic acid. How is it prepared?

According to the sigma document you referenced (emphasis added by me): "The free acid is soluble at 0.24 g/L in water at 15ºC, while the sodium salt is soluble at >333 g/L in water at 15ºC. ...
MikeyC's user avatar
  • 4,787
4 votes

DNA quantification in a high school bio lab

Within some linear range, the intensity of stained DNA bands in a gel is directly proportional to their mass. By making a standard curve from bands of known mass, the mass of unknown bands can be ...
canadianer's user avatar
  • 17.8k
4 votes

Is there a reliable source for storage and stability of reducing agents like DTT?

Thiol-Based Reducing Agents The instability of thiol-based reducing agents in solution is due to their propensity to form disulfide bonds by the following half reaction: $$\ce{2RSH -> RSSR + 2H+ +...
canadianer's user avatar
  • 17.8k
4 votes

How pricey does the media need to be for a typical bacterial culture experiment?

It looks like Merck have different levels of quality control for their products. MQ 100 being the lowest up to MQ 600 being the highest. From what I can see the MQ200 product here has defined ...
JEJS's user avatar
  • 441
3 votes

How standardized is lab-grade skim milk?

There is a degree of variability in milk, and in some cases this cause problems in protein work. Despite being a standard for ELISAs, it's not known to be the most reliable blocking buffer. As far as ...
Catherine's user avatar
  • 191
3 votes

How pricey does the media need to be for a typical bacterial culture experiment?

The answer depends on the application and level of oversight/compliance you require. Most research labs I've seen use de-ionized or even reverse-osmosis water (from a tap) for most culture media ...
MikeyC's user avatar
  • 4,787
3 votes
Accepted

Ordering Primers: When to choose wet vs dry delivery format?

Pros of wet: No need to rehydrate to use. For e.g. 96-well plates, this can be a big deal as it's a pain to do this for large numbers of samples. More accurate concentrations (oligo manufactureres ...
Maximilian Press's user avatar
3 votes
Accepted

Using autoclaved store-bought distilled water for labwork?

Yes, distilled water would be absolutely fine for your needs. You really don't need ultrapure water except for the most sensitive of applications. You also don't need to autoclave the distilled water ...
canadianer's user avatar
  • 17.8k
3 votes

Agarose gel Ladder smear

Are you sure that your TBE is at the right dilution? And that you're using TBE to make the gel and also as the buffer for running? That sort of wavy line looks like what you might get if you'd made ...
mykinz's user avatar
  • 41
2 votes

Agarose gel Ladder smear

Try going even higher with the agarose concentration, as it looks like you have decent separation of the small bands and poor separation of the large bands. Also try a fresh batch of agarose. I ...
Jeppe Nielsen's user avatar
1 vote
Accepted

Washing buffers for protein identification?

All the unoccupied sites on the membrane are saturated in the blocking step after the transfer of the protein gel to the membrane. You can prepare the antibody solution in pure buffer, but you should ...
Chris's user avatar
  • 51.7k
1 vote

How pricey does the media need to be for a typical bacterial culture experiment?

This answer only concerns Streptococcus pneumoniae. The lab I worked in used cheap ingredients, the same as everyone else claimed to in this field. The only shocking thing I found was that the ...
Polypipe Wrangler's user avatar
1 vote

Use lab agar for cooking

Technically agar has first been used (and still is) in the kitchen and then adopted to the lab. In the 19th century, gelatin was used in the microbial laboratory. The problem is that gelatin is much ...
Chris's user avatar
  • 51.7k
1 vote

FPLC based separation of serum proteins

Firstly, may I suggest 2D electrophoresis as a technique for identifying differences in protein/marker expression levels. This technique will give you greater resolution and ease of comparing your ...
Jack Brown's user avatar

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