Detection of Positions of Genes of β-Carotene Production by

Abstract

Two procedures was followed to determine the position of β-carotene pigment coding genes.The first procedure is curing of plasmid nucleic acid content using ethidium bromide with 150 μg/mlconcentration for each the yeasts Rhodotorula. mucilaginosa BA61, Sacharomyces cervisiae BA179and Escherichia coli BA252. The results revealed that success of curing of plasmid DNA forthe yeast R. mucilaginosa BA61. The cured colonies was bearing β-carotene pigment productioncharacteristic and the genes responsible for this characteristic laid on the chromosome, as longas, the curing did not occur. The curred colonies showed sensitivity against the studied antibioticswith percentage ranged from 16-80% with exception with Ampicillin, Erythromycin, Lamisil andVancomycin. Also results of curing of the yeast S. cervisiae strain BA179 losing of antibioticresistance with the range 15-92%. Results of curring of E. coli BA252 strain showed losing ofantibiotic resistance with percentage 15-23%, with exception with the Trimethoprim, Erythromycinand Lamisil.The second procedure for determine the position of coding genes was done by conjugation,which two conjugation attempts was done. The first one for determine the ability of plasmid nucleicacid for mobilization and transferation in yeast strains. There was success conjugation between donoryeast strain R. mucilaginosa BA61 and the curred yeast S. cervisiae BA179 as recipient withconjugation frequency 0.65× 10-8, this study proved that the transferred plasmid nucleic acid fromR. mucilaginosa BA61 bearing Gentamicin antibiotic genes, but not genes responsible for β-carotenepigment production, as well as, two attempts of conjugation was done through kingdoms betweenR.mucilaginosa BA61 as a donor and E. coli BA252 as recipient. Results revealed that plasmidnucleic acid bearing Rifampin resistance genes has the ability ofmobilization and transferation fromthe yeast to the bacteria with conjugation frequency 3.05×10-8. Results also showed that the curredbacteria has the ability of receiving and stability of plasmid from the yeast by conjugation,whereas the resulting was not bear production of the β-carotene pigment characteristic and thisconfirm that the genes coding for pigment production characteristic bearing laid on chromosomalnucleic acid.