[Fluorometric evaluation of aflatoxigenic strains of the molds Aspergillus flavus and Aspergillus parasiticus after culture in liquid medium].
The production of aflatoxin (AF) by A. flavus and A. parasiticus strains originating either from the Czechoslovak collection or isolated from feed mixtures and from peanut samples was determined following their cultivation in liquid synthetic GV medium. Their aflatoxicogenic effects were estimated from fluorescence of the GV medium after its application onto filter paper or by determining emission intensity of chloroform extracts of the medium in a fluorescence spectrophotometer. In extracts with emission intensity from 0 to 880 at two sensitivity settings of the device, AFB1 concentration was found to be in the range from 0 to 54.5 mg.l-1 when determined by means of the RIA method. Emission intensity was not in a linear relationship with AFB1 level in the medium and was higher than at a corresponding concentration of AFB1 standard solution. The fluorometric method is many times more sensitive than visual assessment of medium fluorescence on filter paper, which, for its part, was more reliable than the estimation of fluorescence following the cultivation of strains with low AF production on solid APA medium. This and other screening methods are surpassed by the employed fluorometric method as far as the sensitivity and saving of time are concerned, especially when medium extract is used for further more precise analysis.
Dvorák
M
M
Láníková
A
A
Kosková
S
S
Diblíková
I
I
D000348:Aflatoxins / Q000096:biosynthesis*; D001230:Aspergillus / Q000254:growth & development / Q000378:metabolism*; D003470:Culture Media; D013050:Spectrometry, Fluorescence
D000348:Aflatoxins; D003470:Culture Media
Fluorometrické hodnocení aflatoxinogenity kmenů plísnĕ Aspergillus flavus a Aspergillus parasiticus po kultivaci v tekutém médiu.