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Abimbola Ismaeel

Does anyone know how to prepare CAS Medium for siderophore...

Bill Gillooly  Follow

Isam Alkhalifawi following the paper (Use of Blue Agar CAS Assay for siderophore detection), they use 3% 8-hydroxyquinoline in chloroform to remove traces of iron from casamino acid solution, can i skip this step or substitue the 8-hydroxyquinoline by something else because i don't have it

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Billy Chang  Follow

Md Khaled Mosharaf
My method was:
Agar Base
LB agar (1/2) (stabilizes bettter the colour)
Peptone 7.5 g/l
NaCl 2.5 g/l
Yeast extract 2.5 g/l
Adjust pH to 6.7
Agar 15 g/l
Blue dye
60.5 mg in 50 ml water
10 ml of Solution Fe+3 (1 mM FeCl3*6H2O in 10 mM HCL)
72.9 mg in 40 ml water
Autoclave Sterilization (separate) 121°C 15 min and then mixing at less of 50°C.
Regards!


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CHIJIOKE OSUMILI  Follow

During the preparation of CAS media your glasswares should be properly clean and sterilised otherwise you won't get blue colour of the media.. this same problem had happened with me too. After following same protocol you mentioned I was not able to get the blue colour. Then one of my senior who is working on siderophore had advised me to properly clean my glasswares with HCl or formaldehyde or sterilise them in hot air oven at 60 degrees. I have did the same and repeated the process of media preparation by same protocol and this time I had got blue colour of my CAS media. May it helps you too

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Arshu Khan  Follow

@Stephanie Riquelme

Thanks

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Alfred Dumasi  Follow

@Stephanie Riquelme Thank you so much for answering. I am repeating the siderophore test and I noticed that my CAS medium is not as blue as the first time I made it. It is more to greenish in color. Is this acceptable? Is there any effect if I use ultrapure water or distilled water?

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David Wilcox  Follow




Hello Wagner,
Your method of CAS agar plate preparation worked perfect to me with Aspergillus sp. Thank you!


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Chris Seymour  Follow

@Stephanie would mixing at over 50 degree Celcius have effect on the color of the medium?

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Azizi Gill  Follow

Munirah Ramli As a general rule, I wait a few minutes until the medium takes a temperature equal to 50 ° C to add vitamins, hormones and compounds as pH indicators. In the case of CAS, I have seen that a stable greenish blue color is generated if you mix with medium at this temperature. Good Luck!

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Dinky Dao  Follow

Hello,

i prepared the CAS solution,
the color was blue at first but after adjusting the pH
to 6.8 it turns yellow, is it normal to find that,
can I have the yellow color after autoclaving .
thanks

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Arthur Renner  Follow




Two years after.... but, in my opinion, a greenish/blue color is acceptable because the halo of the reaction of the medium with the microorganism is observable. In this picture, I made a batch with that color, and works perfectly.

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