I had test the killer effect of the yeast and I found some colonies seem to have an misty inhibition zone rather than a clear inhibition zone on plate as you can see in the picture. Is there any academic definition of this phenomenon? Can I say it is inhibited or resistant? I didn't see any paper discuss about this or I use wrong key words.
It is clearly retarding the growth rate. What is the difference between the two plates/ yeast colonies?
Robert Adolf Brinzer The only difference of the two plates is the background (sensitive) yeast, left one is Candida sp. and the other is Pachysolen sp.
maybe it's a question of the yeast cell load you used to inoculate the dishes. I advise you to repeat the experiment first, also measure the diameter to have an idea, because even with this area which is not clear, your yeast may be resistant because it has not exceeded the diameter which allows to say that it is sensitive.
Misty zones may indicate partial inhibition, and additional experiments may be needed to better characterize the effect of the antimicrobial agent. Classification depends on specific criteria used.
Sofiane Benyamina and Armin Hosseinpour Nader Actually my first think is the yeast cell load and I did the test, however the misty zones still appeared even I reduce the cell concentration inoculated the dishes.
So it's kind hard to define partial inhibition or resistant.
Based on the information you have provided, it is difficult to determine the exact cause of the misty inhibition zones. However, it is possible that the antimicrobial agent used in the assay may not be fully effective against the yeast strain being tested, leading to partial inhibition rather than complete clearance of the growth. Alternatively, the misty zones could be caused by uneven distribution or diffusion of the antimicrobial agent on the agar surface.
Also, check as even the diameter of the zone, maybe despite this unclear zone, your yeast remains resistant and in this case your problem is solved.
I see these are different species.
Think you should explain further. The left plate includes a number of discs about which some show no apparent inhibition.
The right plate offers the opportunity to culture the light growth betwree apparent margin and the disc. Perhaps it is resistant.
Thank you for all the valuable informations and ideas and sorry I didn't explain very well to all of you about this experiment.
The discs on the plate actually are 21 killer yeast strains (same species) used to test whether the killer toxins they produced can kill the yeast (Candida sp. in the left and Pachysolen sp. in the right) I inoculated on the plate.
After I viewed all the comments, I think the most possible reason to the misty zone might be the growth rate of the inoculated yeast is higher than the toxin produce rate to make it has light growth.
I think I can culture the killer yeast in broth to increase the toxin concentration first and do the serial dilution of the culture broth to test again by well method.
If the misty zone become clear it could be the reason I mentioned or it still misty than I will think it's a resistant variant.
I am not sure this is such a strong evidence or maybe you have any idea we can discuss.
It's a great suggestion, I will also subculture from the misty zone and do the test. Thank you.
- Badges
- Science topic
- Similar topics
- Biological Science
- Microbiology