Is is possible that the enzymes are active but are preferentially digesting
peptides etc in the media in preference to the bacteriocin ? The media
constituents will be in a massive excess compared to the bacteriocin and so
may 'mop up' the enzymes leaving the bacteriocins relatively untouched.
Another possibility is that the bacteriocins may be protected from digetsion
by being boud to cell wall constituents.
Derek Law
Company Microbiologist
Lab M
"Mike Dew" <internul1 at hotmail.com> wrote in message
news:LAW2-F32TaGmvSVMum0000006ae at hotmail.com...
> Hi,
>> for a work on bacteriocin production from lactic acid bacteria, I use the
> deferred antagonism assay with good results. Many isolated strains (116
out
> of 1000) inhibit the target bacteria (Listeria) on solid media (BHI,
TSA-YE,
> APT).
> However, I cannot succeed to stop the inhibition by adding several
> proteolytic enzymes commonly used for this purpose.
>> The enzymes (protease, trypsine, proteinase K) are solubilized in PBS
0.01M
> at 10mg/mL, and a few ug are deposed on spots of lactic cultures on solid
> media, and an overlay is added containing Listeria. But the inhibition
zones
> are still present. Obviously, maybe there are no bacteriocin-producing
> strains, but what can cause the inbition (clues: no peroxyde because
> anaerobiosis; no bacteriophages detected; no acidification because of the
> no-glucose TSA-YE) ? Is this enzyme methodology inadequate ?
>> Thank you for help !
>> Mike Dew
> Center for aquatic innovation
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