Field of Science

Counting the GFAJ-1 cells

I looked at some of the GFAJ-1 cells on the plate I received under the microscope.  The Wolfe-Simon paper hadn't mentioned that they are motile, but it was reassuring to see them vigorously swimming around.

But they're little!  Not as tiny as Haemophilus influenzea, but quite a bit smaller than E. coli.  Their size made counting them with the hemocytometer a challenge - the hemocytometer is so thick that it messes up the microscope's optics, especially at high magnification, and my eyeballs are chock full of tiny floaters that aren't a problem in normal vision but look just like GFAJ-1 cells when I'm using a microscope.

Wolfe-Simon used the fluorescent dye acridine orange to stain the cells for counting.  We do have acridine orange in our extensive collection of laboratory stains (scored from an old lab that was shutting down: we've never used most of them).  And our microscope has fluorescence illumination, thanks to an investment by the lab next door - I'll have to ask them how to use it.

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