Analysis of yeast DNA using pulsed field gel electrophoresis

Technique of pulsed field gel electrophoresis (PFGE) has found widespread use in the analysis of the genome of all life organisms. It is applied to the separation of the large DNA molecules above thousands base pairs up to millions of base pairs in size, where using conventional gel electrophoresis techniques are not possible (for instance large bacterial, yeast, fungal or mammalian chromosome). Presented work was realized as a comparative analysis of genome of several carotenogenic yeasts. The conditions of isolation and analysis of chromosomal yeast DNA were optimized. A lysis of yeast cells and deproteination of DNA within agarose chops was shown as the most appropriate method for DNA isolation. Cultivation to late exponential phase (50 hours) is the most suitable to obtaining intact DNA in sufficient amount and quality. Carotenogenic yeasts undergo the random mutagenesis using alkylation reagent ethyl methanesulfonate (EMS). Genome of pigment overproducing mutants was analyzed by pulsed field gel electrophoresis and amount of carotenoids by high pressure liquid chromatography (HPLC). However, overproduction of beta-carotene was analyzed in mutant strains Rhodotorula glutinis (10.6 g/l of biomass enriched 0,34 mg/g of beta-carotene) and Cystofilobasidium capitatum (8.5 g/l of biomass enriched 0,23 mg/g of beta-carotene). Selection of mutant strains overproducing carotenoid pigments was in presented experiment series successful in almost all analyzed strains except in the case of the strain Rhodotorula aurantiaca