2 replies to this topic

[ColdOven14]

I will be researching in Antarctica at the end of the year and as such, I wont have an epifluroescence (only a compound) microscope available.
I need to conduct viability counts of prokaryotic bacteria, most likely using a haemocyctometer, and am looking for a stain which could be used for this purpose. I've looked into Trypan blue but have a few specific questions about it.
1) Can it be taken up by prokayotic cells?
2) Is there a counter stain available which I can use to for counting my live bacteria?
Any help in regards to trypan blue or alternative stains would be greatly appreciated.

[Curtis]

This is a very good question. I am not sure how Trypan Blue would work on gram-positive bacteria. In order to differentiate living cells from dead ones we normally just grow them in broth and check OD. But that would need an incubator and a spectrophotometer, which you might not have in Antarctica. I searched the web just now, there are some commercial kits, but most of them use propidium iodide and that needs fluorescence microscope. Then I searched PubMed but couldn't find anything useful either. So I also want to know the answer. If anybody knows please let us know.

[ColdOven14]

We will have an incubator and spectrophotometer down there. I've planned on measuring optical density to get some growth curves. How does OD differentiate between live and dead cells though?
I saw a few of those kits, like the live/dead BacLight and they looked pretty cool but as you said, all I could find were fluorescence stains.