Authors:Anita Risa, Dalma Maja Divinyi, Erzsébet Baka and Csilla Krifaton
AflatoxinB1 (AFB1) is one of the most harmful mycotoxins occurring almost worldwide. Aflatoxins are a group of several compounds mainly produced by Aspergillus flavus and Aspergillus parasiticus [ 1 ] but more
The specificity of radioimmunoassay of aflatoxin B1 was tested. Relative cross-reactivity of used antiserum with aflatoxins B1, B2, G1, G2 and M1 was found to be 100%, 24%, 44.2%, 10.3%, and 1.4%, respectively. The interference of coumarin, albumins, steroids and ethylvanilin was estimated also in radioimmunoassay of aflatoxin B1. Thus these compounds may cause a false positive finding of aflatoxin B1.
Authors:A. Korde, S. Banerjeė, M.R.A. Pillai and M. Venkatesh
Aflatoxin B1 (AfB1), present in fungus infested crops is highly carcinogenic and is measured by immunoassays. 125I labeled aflatoxin B1 is a key reagent for development of radioimmunoassay (RIA) which exhibits less interference and better sensitivity than other immunoassays. Since AfB1 lacks suitable functional groups for radiolabeling, an oxime derivative of AfB1 was synthesised and evaluated by UV-spectrophotometry and 1H NMR spectroscopy. 125I-histamine was conjugated to AfB1 oxime by mixed anhydride method and purified by solvent extraction followed by TLC. The tracer obtained was immunoreactive, stable as ethanolic solution and could be used in RIA.
Authors:László Pál, Károly Dublecz, Mária Weber, Krisztián Balogh, Márta Erdélyi, Gábor Szigeti and Miklós Mézes
, T. (1994): Multi-functional column coupled with liquid chromatography for determination of aflatoxinsB1
in corn, almonds, Brazil nuts, peanuts, and pistachio nuts. Collaborative study. J. AOAC Int.
The effect of acetone and methanol contents in an aqueous casein-buffer solution pipetted with aflatoxin B1 into radioimmunoassay procedure, on some parameters of radioimmunochemical determination of aflatoxin B1 has been studied. These organic solvents lower an antiserum titer and value of the zero specific binding, and at higher concentrations make worse the detection limit and the accuracy of radioimmunoassay. However, in radioimmunoassay of food extracts containing subresidual levels of aflatoxin, it could be advantageous to add the extract volume to the organic solvent concentration of 60%.
Authors:L. Fukal, J. Prošek, P. Rauch, Z. Sova and J. Káš
Aflatoxin B1 was assayed by radioimmunoassay (RIA) using125I-labelled antigen. The immunoreactivity of the radioligand applied is very close to the immunoreactivity of free aflatoxin B1. The logit-log analysis was used to select the best separation of free and bound radioligand. The adsorption of the free radioligand on dextran-coated charcoal was found to be superior from the viewpoint of the assay sensitivity and accuracy. The detection limit of aflatoxin B1 was about 10 pg per tube. The assay accuracy was estimated to 3.3% in intraassay and to 7.0% in interassay.
Authors:L. Fukal, J. Prosek, P. Rauch, Z. Sova and J. Káš
Assay conditions for the radioimmunoassay for aflatoxin B1 using125I-radiolabel and dextran-coated charcoal for the separation of free and bound radioligand were optimized. Casein was chosen as the best protecting protein /in contrast with human serum albumin, -globulin and gelatine/. The most suitable incubation conditions are at 4°C for 18 h in darkness, radioligand sorption on the dextrancoated charcoal takes place 30 min at 4°C and the antiserum is diluted in order to reach zero specific binding in the range between 35 and 50%.
): Role of oxidative stress in sclerotial differentiation and aflatoxinB1 biosynthesis in Aspergillus flavus . Appl. Environ. Microbiol. 80 , 5561 – 5571 .
Howlett , B. J. ( 2006 ): Secondary metabolite toxins and nutrition of plant pathogenic
Authors:Ágnes Móricz, Nóra Adányi, Erzsébet Horváth, Péter Ott and Ernő Tyihák
Bioautography can be extended to a complex system called BioArena by linking different steps to it, for example dissolving a variety of compounds in the cell suspension to affect biological activity, measuring putative mediators of antibiosis, for example formaldehyde (HCHO) and hydrogen peroxide (H
) in the inoculated layer, and performing densitometric and ex and
spectroscopic examination to follow the changes in the inhibition zones and active compounds (e.g. antibiotics and toxins). Possibilities of the basic elements of BioArena system are illustrated in this paper by results with aflatoxin B1 (AFB1). Target bacterial cells in the logarithmic growth phase were found to be the most sensitive for direct bioautography. Densitometric signals of bioautograms (negative densitometry) of 0.125–1 μg AFB1 spots showed logarithmic correlation with the amount of AFB1. The HCHO capturer L-arginine decreased whereas the HCHO generator-mobilizer Cu(II) ions increased the antibacterial-toxic effect of AFB1. The latter effect was also confirmed by negative densitometry. Besides higher levels of HCHO, a decrease of H
in the toxin spot was found. HCHO could also originate, among other sources, from demethylation of AFB1, which is apparent from the
spectra obtained in situ from the AFB1-containing spots. These results support the suggested role of HCHO and its reaction products with H
(e.g. singlet oxygen (
), ozone (O
)) in the antibacterial-toxic effect of AFB1.