PubMed · 11680494
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2001-10-01. Cumulative index for Mutation Research.. https://pubmed.ncbi.nlm.nih.gov/11680494/
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Patulin is a mycotoxin produced by certain fungi, such as those found commonly on apples. The patulin content of apple juice is a regulatory concern because patulin is a suspected carcinogen and mutagen. A simple model of the apple juice concentration process was carried out to examine the possible contamination of patulin in apple aroma, a distillate produced commercially in the concentration of apple juice. The results show no evidence for patulin volatility, and document a reduction in patulin content by at least a factor of 250 in the apple distillate obtained from apple juice. Furthermore, a survey of several commercial apple aroma samples found no evidence of patulin content.
Three-layer artificial neural networks (ANN) with back-propagation of error have been applied to classification of nitro-substituted polycyclic aromatic hydrocarbons (NPAH) based on the regularity that the structure difference of NPAH compounds leads to different mutagenic activity towards Salmonella typhimurium. The network's architecture and parameters were optimized to give maximum correct classification rate of 93.8% for two different classes of NPAHs: weakly active and strongly active ones. The results compared favourably with those obtained by nonlinear mapping pattern recognition method. Considering that the most important factor for NPAH's mutagenicity might be the electron effect of the substituted nitro-groups, an electrotopological state index of nitrogen atom was introduced additionally as one of network's inputs, and the correct classification rate was consequently raised to 97.5%. The network's prediction ability for untrained samples was also satisfactory.
Azido-IQ (2-azido-3-methylimidazo[4,5-f]quinoline), a novel analog of the food mutagen and carcinogen IQ (2-amino-3-methylimidazo[4,5-f]quinoline) was synthesized and characterized. Both thermolysis and photolysis of this azide yield a short-lived nitrene which can react as an electrophile either directly or via protonation to a nitrenium ion. Reaction of the nitrene/nitrenium ion with water produces N-hydroxy-IQ; reactions with nucleotides and with DNA (in vitro and in cells) produce adducts efficiently. Correspondingly, high frequencies of mutations are induced in Salmonella typhimurium by photolyzed azido-IQ. Comparative mutation assays with the S. typhimurium strains TA98 and the hydroxylamine-resistant TA98/1,8-DNP6 provide evidence for a novel mechanism of mutation, direct reaction of the nitrene or nitrene-derived nitrenium ion with DNA without involvement of the hydroxylamine. The photolysis of arylazides promises to be a very convenient and generally applicable non-enzymatic procedure for the cell-free or intracellular generation of short-lived and highly reactive electrophilic species which are assumed to be identical with the metabolically formed ultimate mutagens/carcinogens of arylamines and nitroarenes.