Hi there,

To have a better idea on the effect of the antibiotic in liquid culture you should monitor growth rate and calculate generation time. Indeed if the antibiotic is only slowing down yeast growth you won't notice any effect if your observation is made at the final time point of the growth.

The other issue you may be confronted with is a trivial one : are the media strictly the same(apart from agar) in the 2 experiments?

Do you use microplates in your assay? Some peptide antibiotics tend to adhere to the surface of polystyrene microplates. Maybe you can check different brands of plates and compare polystyrene, cycloolefin and polypropylene manufactured plates. In addition, the solvent you use in your liquid assay may have an effect on aureobasidin.

Thanks for your help, to answer both your questions:

Dominique,

I will look into how it affects generation time.

The media is the same except for the addition of agar in the plates.

Oliver,

I do use microplates (only one type thus far) - I'll see if mixing up the plates changes the outcome.

yes