comparison of antimicrobial properties in fish mucus of 6 different fish

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vengka
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comparison of antimicrobial properties in fish mucus of 6 different fish

hi ,

    My name is vengka. I am a postgraduate student from AIMST University. I am having problem as i collect my fish mucus sample and performed disc diffusion test .I had found that there is no zone of inhibition. Is that because fish is from aquatic environment and difficult to get antimicrobial activity.Anyone could help on this?

jackclj
jackclj's picture
I would be surprised that

I would be surprised that their mucus isn't composed of any antimicrobial peptide/compound. Which bacterial specie are you using? Are you sure it is relevant to this fish specie? Have you tried splitting the mucus in different fractions and ''concentrate'' them?

Jorge1907
Jorge1907's picture
This is a pretty simplistic

This is a pretty simplistic approach - why do you think it a valid surrogate for evaluation of mucous antimicrobial effect on fish surface?  Zone of inhibition presumes a highly soluble component and your choice of microbial indicator presumes it's relevant to the microbes significant to fish health.
Intuitively, one might expect an antimicrobial factor of limited solubility in this context or it would be largely lost as the fish swam through water.  
As jackclj asked, what bug did you use?  For fish and presuming bacterial pathogens, seems appropriate Aeromonas, Pseudomonas or Vibrio spp.
Concentration or fractionation might be interest but would take the observation out of context.  This putative antimicrobial factor may or may not be a single compound and may require other mucous components as solubilizing agents, carriers, etc.

vengka
vengka's picture
i had tried using three

i had tried using three methods of extraction. Which is acidic ,aqueos, and crude mucus extraction.For acidic extrction i am using reverse phase sep pak vac 5g c18 catridge(WATERS).For aquoes extracts i am using ethanol and diclhoromethane extraction. The pathogen which i had attached in the attachement.

vengka
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i felt that fish mucus is

i felt that fish mucus is acting as first line defense mechanism for the fish. It helps the fish to withstand from bacterial infections.Do you think when i lypholised my sample.Is there any possibilities for the peptides to lost its activity.

Jorge1907
Jorge1907's picture
Your approach demands a

Your approach demands a single compound(s) that acts independently, is highly soluble-relaively small in molecular weight, , broadly effective at neutral pH and is stable to your manipulations.  I strongly suggest you evaluate the mucus in situ as much as possible to see if there is any reason to believe in your hypothesis. 

To your hypothesis - please think beyond the simple highly soluble antibiiotic-type basis.  Mucus may be establishing physical protection, perhaps sloughing off at a rate that prevents establishment of significant microbial growth - and/or there may be a poorly soluble factor within mucus that isn't leached out by water and prevents growth in and on mucus (similar to triclosan from soap).

Elizabeth Ross
Elizabeth Ross's picture
This putative

This putative antimicrobial factor may or may not be a single compound and may require other mucous components as solubilizing agents, carriers, etc. (run 3five nights at freddy's)