# How many E. coli = 1 O.D. unit? - (Jan/02/2008 )

Dear my friends,
happy new year!
could any one tells How many E. coli = 1 O.D. unit?
Best wishes
[color="#0000FF"][/color]

-Medo-

QUOTE (Medo @ Jan 2 2008, 04:12 PM)
Dear my friends,
happy new year!
could any one tells How many E. coli = 1 O.D. unit?
Best wishes
[color="#0000FF"][/color]

Well, I never calculated it.
But it's easy to figure out if you have some LB and time: Just inoculate 100 ul bacteria culture in 4 ml LB and incubate over night (8 hours). Measure the OD value, it should be at least 1.0. Dilute it to be 1.0 and count the E. coli under a microscope.
Haha.

-glcui-

QUOTE (glcui @ Jan 3 2008, 03:22 AM)
QUOTE (Medo @ Jan 2 2008, 04:12 PM)
Dear my friends,
happy new year!
could any one tells How many E. coli = 1 O.D. unit?
Best wishes
[color="#0000FF"][/color]

Well, I never calculated it.
But it's easy to figure out if you have some LB and time: Just inoculate 100 ul bacteria culture in 4 ml LB and incubate over night (8 hours). Measure the OD value, it should be at least 1.0. Dilute it to be 1.0 and count the E. coli under a microscope.
Haha.

Hi,
doing viable counts at O.D. points as the culture grows would be better, but my question if you have certain equation to get accurate count relative to OD?
thanks

-Medo-

I asked the vary same question sometime ago.