Enhancement of cells fusion using magnetic field in sexually homogeneity Saccharomyces cerevisiae strains [electronic resource].

Includes references.

Most methods involving the hybridization of yeasts aimed to producing new organisms with sets of desirable characteristics and frequently requires the integration of properties from two parental strains. Protoplast fusion has emerged as an important yeast breeding technique Fusion between two homothallic strains do not occurred because cell wall involved similarly pheromones (related to the same mating type). Novozym is one of lytic enzymes used herein for protoplast formation. The flux density of Magnetic Field (MF); 0.7mT (millitesla or 7Gauss) was played an important role to arise protoplast formation and fusion. MF was decreased 75% of lytic enzyme concentration used in protoplast formation. Yeast cell cultures exposed to MF were achievement for single cell separated by micromanipulator unit. The Cells grown in YPD medium for 24hr were transferred into starvation medium for 4hr. Exposure time of MF were 5,10 and 15 min to detected cell viability As soon as, the exposure time for 5min and 10 min were used for protoplast formation and fusion, respectively. The prtoplasts formation percentages were 33 and 50% in GT160 and GM3 yeast strains, respectively. The protoplast volumes were related with responsibility of yeast strains in protoplast formation. The diploid phases were selected on selective medium contained Phloxin-B stain which appeared each haploid, diploid and dead cells. The diploid phases were encouraged to entire meiotic division by asci formation. The ascospores were transferred into complete medium supplemented auxotrophic requirements and CUS04 to aide obvious visible color. The genetic analysis were detected the dominant and recessive alleles. All dominants alleles were exist with high percentages. Only the leu gene which was defected in the two strains emerged very low dominant percentage. Ethanol production from two haploid strains and diploids were determined for example of biological activity. Diploids have been record the highest production after 2hr. Ethanol production values were significant after 6hr. Percentage of cells viability measured from unbudding I budding numbers was the other side of biological activity. MF decreased formation of buds exposing for 5 or 10 min through 1, 2 and 3 hr from the fermentations. While, exposed for 15 min did not rform any buds in two strains. RAPD-PCR reaction was conducted using three primers; two from them were attached with genomic DNA extracted. The exposure time of MF due to disappeared DNA bands, the exposing for 10 min was high effect than 5 min. This work assumed that MF might be utilizes for genetically improvement of economic microorganisms have default sexual cycle.

Summary in Arabic.

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