Staining of Chromosomes

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MicroscopyLearning
Posts: 64
Joined: Wed Feb 10, 2021 2:50 pm

Staining of Chromosomes

#1 Post by MicroscopyLearning » Mon Jan 17, 2022 7:15 pm

Hello. Recently I have been wondering how to stain the chromosomes of a cell. I have seen multiple sources saying to use the stain Safranin. How would you recommend applying this stain, should it be diluted first and then applied? The safranin I use is a 1 percent aqueous solution. Also, does anyone know how much magnification would be needed to view the chromosomes? Thank you for any advice you can give.

MicroBob
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Location: Northern Germany

Re: Staining of Chromosomes

#2 Post by MicroBob » Mon Jan 17, 2022 9:39 pm

Something like chomosomes in root tips?

Alexander
Posts: 173
Joined: Fri Jun 11, 2021 7:10 pm

Re: Staining of Chromosomes

#3 Post by Alexander » Mon Jan 17, 2022 9:44 pm

Chromosones are very much borderline for any light-microscope. I recommend to use fluorescence to visualize them.

DrPhoxinus
Posts: 259
Joined: Mon Jan 28, 2019 5:17 pm
Location: Rochester Hills, MI

Re: Staining of Chromosomes

#4 Post by DrPhoxinus » Tue Jan 18, 2022 12:13 am

I have done karyotypes of fish and lizards.
Metaphase is very brief in the cell cycle so to get a reasonable number one has to arrest cells with colchicine.

I used Giemsa stain.

If you are talking about plants you need meristems.

Prepping to see chromosomes can be hard.

Leitzcycler
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Joined: Mon Sep 09, 2019 11:55 am

Re: Staining of Chromosomes

#5 Post by Leitzcycler » Tue Jan 18, 2022 8:04 pm

Chromosomes are difficult to find without using special techniques. The best way to start is to use onion root cells. You may google plenty of procedures. According to my experience the most important thing is to use proper material. You grow roots and only use the very fresh tips. I think any general stain will do although Giemsa is probably one of the best. Chromosomes are of different sizes depending on the organism. Onion chromosomes are rather big and can be well seen with 40x objective.

Good Luck!

DrPhoxinus
Posts: 259
Joined: Mon Jan 28, 2019 5:17 pm
Location: Rochester Hills, MI

Re: Staining of Chromosomes

#6 Post by DrPhoxinus » Tue Jan 18, 2022 8:16 pm

Speaking of variation in chromosomes, while in Florida I came across one of these

https://en.m.wikipedia.org/wiki/Amphiuma_pholeter

It has 28 times the DNA as a human and a 10x objective did not have enough field of view for a chromosome spread

Acetocarmine appears good for onions

https://www.vedantu.com/question-answer ... 5b3a0b01f0

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