Mutagenicity induced by hyperthermia, hot mate infusion, and hot caffeine in Saccharomyces cerevisiae

Mate, an infusion containing caffeine (3 g/liter), is drunk hot by most Uruguayan, North Argentinian, and South Brazilian people. This beverage has been recently associated with esophageal cancer in Brazil and Uruguay. To test the mutagenic and lethal effects of mate infusion, caffeine, hyperthermia, and their combinations, we used Saccharomyces cerevisiae as an eucaryotic model system measuring lys to LYS reversions. We showed that mate infusion was not mutagenic, whereas caffeine at the same concentration contained in mate, produced a 5-fold increase in the spontaneous mutation rate. The highest observed mutagenic rate corresponded to hyperthermia (54 degrees C at 60 min). Hot caffeine also produced a time-dependent mutagenic effect, whereas hot mate infusion determined a significantly lower mutagenic effect than hot caffeine. The differential lethality produced by the tested agents plays an important role in the expression of the induced mutagenic damage. Caffeine and mate infusion could decrease the mutagenic effect of hyperthermia through the channeling of part of the induced DNA lesions into an error-free repair pathway.