E. Coli glycerol stock cytometry

About microscopic forms of life, including Bacteria, Archea, protozoans, algae and fungi. Topics relating to viruses, viroids and prions also belong here.

Moderators: honeev, Leonid, amiradm, BioTeam

Post Reply
Leon Fnord
Posts: 1
Joined: Wed Nov 28, 2007 11:17 pm

E. Coli glycerol stock cytometry

Post by Leon Fnord » Wed Nov 28, 2007 11:35 pm

I have recently been trying to count E. coli using a Petroff-Hauser counting chamber. I wanted to count cells straight out of my glycerol stocks, but I am having difficulties.

The E. coli looks strange directly after the glycerol stock is thawed.

My Procedure:
Thaw the E. coli cell bank (glycerol stock) at 37 C.
Dilute the cell bank at a 1:10 dilution in saline & pipette 50 uL into the counting chamber.
View on scope at 400X magnification.

Specifically, the cells look elongated and many appear to be fused together in a linear orientation. Often times, several appear to be fused in chains of 5 or 6 individual units. This is strange because if I view E. coli from a live and growing culture, I can see discrete cells. :?

Can anyone explain to me what I am observing? Is this common? What causes it? Are there any handling precautions I can take to minimize this phenomenon?

Post Reply

Who is online

Users browsing this forum: No registered users and 1 guest