TESTING THE ABILITY OF PLASMID DNA CONTENT IN Debaromyces hansanii FOR MOBILIZATION AND TRANSFER THROUGH CONJUCATION

The current study included isolation of yeasts from the leaves of different types of citrus trees, and it was diagnosed based on phenotypic, culture and biochemical tests. The results showed that the yeasts belong to the species: Saccharomyces cerevisiae and Debaromyces hansenii. Also, Escherichia coli bacteria were obtained from the exit of infants in Ibn Al-Atheer Teaching Hospital in Mosul/ Iraq and was diagnosed based on biochemical tests. The resistance of isolates was studied for 20 antibiotics and 8 heavy metal ions. The results showed that S. cerevisiae is resistant to antibiotics (Amoxicillin, Ampicillin, Cephalexin monohydrate, Chloramphenicol, Clindamycin, Clotrimazol, Erythromycin, Getamicin, Newmycin, Penicillin, Tetracycline, and Vancomycin) and sensitive to Candizol, Fluconazole, Ketoconazol, Lamisil, Nystatin, Rifampin, Streptomycin, and Trimethoprim. While D. hansenii showed resistance to all antibiotics except Ampicillin, Candizol, Clindamycin, Clotrimazol, Erythromycin, Newmycin, Penicillin, and Tetracycline. The resistance of the two insulators differed towards heavy metal ions, as the two insulators were resistant to Nickel Chloride and Cobalt Chloride ions and Copper Sulfate sensitive. The ability of bacteria to resist antibiotics and heavy metal ions has been studied. The results showed that it showed sensitivity to Amoxicillin, Cephalexin monohydrate, Chloramphenicol, Getamicin, Newmycin, Nystatin and Streptomycin and resistance to the rest of the antibiotics used, while it was resistant to all heavy metals except for Cadmium Chloride, Mercury Chloride, and Zinc Sulfate.

Curing of plasmid DNA content of S. cerevisiae was succeed. The curred colonies showed sensitivity to the studied antibiotics at 15-84%, except for Ampicillin, Erythromycin, Lamisil and Vancomycin. The results of curing E. coli also showed a loss of antibiotic resistance in the range of 16-50%.

The conjugation between D. hansenii and S. cervisiae was successful as a acceptor with a conjugation frequency of 0.68×10-8. This study demonstrated that the transported plasmid DNA from D. hansenii carries antibiotic resistance Clotrimazol genes. In addition, an attempt was made to cross-kingdom conjugation between the yeast D. hansenii as a donor and E. coli as receptor. The results showed that the plasmid DNA carrying the Nystatin resistance genes has the ability to move and move from yeast to bacteria with a conjugation frequency of 2.05 × 10-8. The results also showed that the cured bacteria have the ability to receive and localize the plasmid from the yeast through the conjugation process.