TESTING FOR MITOTIC GENE CONVERSION IN YEAST BY FOOD COLOURS AND OTHER CHEMICALS

Abstract

Food additives comprise a large group of chemicals which are of direct concern to the human. They are not only enormous but also have a widespread use. The present study was initiated to asses the mutagenic and .possibly carcinogenic potential of a number of food colours and flavours. These additives are widely used in Fakistan and other parts of the world in a variety of food products. Altogether, 43 food colours and 20 flavouring agents have been tested. The tested colours, representatives of the major structural classes of synthetic food colours, include Tartrazine, Sunset Yellow FCF, Orange H.K., Lemon Yellow, Metanil Yellow, Amaranth, Ponceau 4R, Ponceau 6R, Madeira Colour, Carminic Acid, Bixine, Indigotine, Syregul, Brilliant Blue FCF, Seelachfarbe, New Blue VN, Azo Rubine, 'Lakee far ge , Violet Acid 5B, Dunkel Blue, Diazolrein Blue 6B, Mocca Brown, Kirsebaerrod, ?atent Blue, Rlspberry Red, Apple Green, Erythrosine, Egg Yellow, Lime Juice Yellow, Chocolate Brown, Congo Red, Orange Red, Direct Brown, Orange G, Rhodamine B, Eriochrome Black T, Methyl Red, Eosin.Y, Auramine o, Rouge S, f hloxine, Pink Rose I and Rose Bengal. The tested food flavours include Strawberry, Raspberry, Orange, Sandal Wood, Vanilla, Afza, Mango, Elachi, Kewra, Lemon, Banana, fine Apple, Green Rose, Almond, Zafran, American Ice Cream Soda, Cardamom, Feppermint, Coconut and Tuti Fruti. These additives were tested using three genetic par namely, mitotic gene conversion, mitotic crossing ove mutation in diploid strains D4 and R:z of the cerevisiae. In statio y pa et

ii AuramineO, Phloxine and link Rose, were tested for the induction of mitotic gene conversion at the ade2 and? loci of 12!±.• The food colour Rouge S was also tested in _E! in log-phase cultures. 11 food colours including Eriochrome Black T, Methyl Red, Rouges, Orange G, Rose Bengal, Eosin Y, Auramine o, Congo Red, Violet Acid 5B, Phloxine and ?ink Rose were tested in stationary-phase cultures of Q2 for the induction of mitotic gene conversion at the ?,mitotic crossing over at the ade2,and reverse mutation at the ilv1 loci. Six food colours including Rouges, Auramine o, lhloxine, Congo Red, Rose Bengal and Eosin Y were also tested in B.z in log-phase cultures. All the 20 flavouring agents were tested in stationary cells fo?the induction of mitotic gene conversion, mitotic crossing over and reverse mutation in both the strains l2;! and QZ• In stationary-phase tests, cells were treated with 1% colour (10 mg/ml) or flavour solution in Sorenson's buffer at pH 5.91, 6.96 and 8.05 for 4 hours at 30°c in the dark. farallel control suspensions, without any test chemical, were prepared. To attest the suitability of the test system, cells were treated with a well known mutagen, •thyl methanesulfonate (EMS). In log-phase tests, the test chemical was added to the growing culture after 24 hours of growth and the treatment terminated after 48 hours.