Growth curve reading on elisa - (May/20/2014 )

Hello ...

I have been dispensing in a 96 wells plate three replicates of 300microliter of inoculated broth (2-3 colonies of bacteria in 10ml broth) .the plate was incubated for 24hrs at 37C to.check the growth phases.The final results and graph of all different bacteria were not steady rather it peaked and then the abs values droped and up again (zigzag curve) With the 3 replicates.

What could be wrong ??

Bubbles on your wells?  The natural course of a growth curve is the classic S curve, with lag phase, log phase (rapid growth) and then plateau.  If your populations get too dense, they can deplete the wells of resources, which means that you will get a decrease in absorbance, which may re-increase with time as the bacteria cope with changes in the media.

Thx for the reply! How can i overcome this ? So using 96 plates might not be accurate to show the end of stationary phase? The wells contained no bubbles but could be what you explained above..as i had similar zizagig curve in a second trial. I thought with automated reading for an overnight incubation i would save myself the sampling and hourly readings . Thx again for the reply!

The obvious way to overcome this, as you suggested, is to do manual readings.  Small volumes are hard to scale accurately for this sort of thing.

Yes sure..thx a lot!