Micro question - choice of dye for simple stain

  1. I'm going through my lab notebook and realized I forgot to answer this question: What factor or factors might influence the choice of dyes in a simple stain? I can't find anything anywhere which lists any reason why you might choose one dye over another. I checked online, checked my book, checked my lab notebook, and emailed a few of my classmates, and still can't find the answer.

    Any help would be appreciated!

    Last edit by fmrnicumom on Oct 15, '07
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  3. by   Jennifer70
    Hmmm, I am in Micro too and not sure on this....could be if you did a Gram stain you would at least be able to classify in either G+ or G-. If those don't show up, you might try Endospore staining (malachite green, heat as mordant, and safranin). The acid-fast stain would help penetrate the waxy coating. (Mycobacterium and Nocardia). I don't know if that helps at all....I am not a brain at Micro, just trying to get by as best as I can with taking APII and Psych.
  4. by   fmrnicumom
    Thanks! I know about Gram stains, acid fast stains, flagella stains, endospore stains, etc. The question is about simple stains though - just one stain, such as crystal violet, methylene blue, safranin, etc., and no special techniques. That's why I'm a little confused, because I can't find anything that says why you might choose one dye over another. I wonder if it's one of those questions where the answer is that you wouldn't choose one dye over another, other than availability?

    Thanks again!
  5. by   happydays352
    crystal violet

    crystal violet, when combined with a suitable mordant, stains cell walls purple. crystal violet is an important component in gram staining.
    malachite green

    malachite green (also known as diamond green b or victoria green b) can be used as a blue-green counterstain to safranin in the gimenez staining technique for bacteria. it also can be used to directly stain spores.

    neutral red

    neutral red (or toluylene red) stains nuclei red. it is usually used as a counterstain in combination with other dyes.

    i guess you could say one would be used to stain and look at spores, another the cell wall, and the third nuclei. so you pick each dye based on what you want to look at.
  6. by   worf
    what about using india ink?

    this is from wikipedia

    indian ink is also used in microbiology as a negative stain. this process stains the background leaving the bacterial cell clear. this technique is most commonly used in the capsular stain in which the background is stained with indian ink and then the bacteria are stained with crystal violet. the result is a dark background, a clear area located at the bacterium capsule, with the bacterium cells appearing purple
  7. by   NoviceRN10
    The one thing that comes to mind is the type of microbe you are using in your exercise. Wouldn't that be a determining factor in which dye you choose?
  8. by   fmrnicumom
    Thanks! Like I said, it was just asking about a simple stain, not counterstaining or acid fast staining or anything else. That's why I was confused. Doesn't matter now, the lab notebook has been turned in. Thank you all for taking the time to answer! I appreciate it.