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
5 votes

How are new staining protocols designed for microscopy?

This answer addresses the question of how stains were developed historically, which may bring into perspective your overly modern assumptions. Most of these older (but stil very usefull!) staining ...
guest's user avatar
  • 254
4 votes
Accepted

Forgot to vortex antibody before staining

It depends on how much time elapsed between adding the concentrated antibodies to the diluting solution and adding the diluted antibodies to the slide. If it was just a couple of seconds, then I can ...
MattDMo's user avatar
  • 15.3k
4 votes

Is there a reliable method to determine if heat fixation was inadequate before proceeding with further staining steps?

I work with a teaching group who has looked at this, specifically for the aim of making things easy for undergrad labs in under-resourced countries, where gas and/or Bunsens or alcohol burners might ...
bob1's user avatar
  • 11.7k
3 votes

Non fluorescent DNA stain to visualize Drosophila polytene chromosomes

Giemsa stain should work. It is traditionally used in karyotyping staining. It results in G-banding.
bob1's user avatar
  • 11.7k
3 votes

Quantifying DNA in a band on gel electrophoresis

All three methods could be used to measure the amount of DNA. However in practice, method 2 (estimation by dye brightness) typically works best in a normal workflow. It really depends on what you plan ...
tswei's user avatar
  • 344
3 votes

Flow Cytometry Channels

I'll amend this answer as I get details from you. What is your cytometer, and how are the optics set up? You typically have 1-5 lasers: UV (355nm), violet (405nm), blue (488nm), green/yellow (~561nm) ...
CKM's user avatar
  • 8,111
1 vote

What is the Importance of Acid Alcohol and Sodium Bicarbonate during staining?

This is described with better detail (and better prose) in John Baker's classic description at StainsFile, but to summarize: The procedure you're describing is a regressive hematoxylin stain with ...
Mike Serfas's user avatar
  • 2,455
1 vote
Accepted

Flow cytometry data Analysis

Disclaimer: Assumes you know how flow cytometry works. You've done a flow-based AnnexinV apoptosis assay here. Annexin A5 (AnnexinV) protein binds to phosphatidylserine (PS), which is typically in ...
CKM's user avatar
  • 8,111
1 vote

Are acid-fast bacteria Gram-positive or Gram-negative?

Taxonomic Classification: The most salient acid-fast bacteria are Mycobacterium spp., which are part of a phylum of gram-positive bacteria called Actinobacteria. This classification is based on 16S ...
canadianer's user avatar
  • 17.7k
1 vote
Accepted

Help analyzing SDS-Page gel

Here are some thoughts based on my own experiences purifying many proteins and running many SDS-PAGE gels: (1) Resolution--how fast did you run this gel? Often if you run at higher than say 150V or ...
user21630's user avatar
1 vote

Barr body Giemsa staining

I think the issue here is the image is a 2D representation of a 3D object. It may well happen that the Barr bodies are below the Geimsa stained nucleus. This is the same reason we don't see ...
Roni Saiba's user avatar

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