RESUMO
Extracts from a range of evolutionarily diverse plant and lichen species from the UK and maritime Antarctic have been assayed for inhibition of ice recrystallization. Approximately 25% of overwintering UK species and all Antarctic species exhibited antifreeze activity when exposed to low temperature. Preliminary characterization of the active extracts has demonstrated that the molecules co-opted to antifreeze activity by different species are biochemically diverse.
Assuntos
Crioprotetores/isolamento & purificação , Proteínas Fúngicas/isolamento & purificação , Proteínas de Plantas/isolamento & purificação , Aclimatação , Regiões Antárticas , Clima Frio , Cristalização , Estabilidade de Medicamentos , Congelamento , Líquens/química , Líquens/crescimento & desenvolvimento , Desenvolvimento Vegetal , Plantas/química , Sacarose , Reino UnidoRESUMO
A modified assay for inhibition of ice recrystallization which allows unequivocal identification of activity in plant extracts is described. Using this assay a novel, cold-induced, 36 kDa antifreeze protein has been isolated from the tap root of cold-acclimated carrot (Daucus carota) plants. This protein inhibits the recrystallization of ice and exhibits thermal-hysteresis activity. The polypeptide behaves as monomer in solution and is N-glycosylated. The corresponding gene is unique in the carrot genome and induced by cold. The antifreeze protein appears to be localized within the apoplast.
