Abstract

DETERMINATION OF THE MOL% G+C VALUES OF BACTERIAL DNA ISOLATED FROM AL-BAIJY OIL REFINERY WORKERS, IRAQ

Dr. Mohemid M Al-Jebouri* and Ashwaq N Al-Doori

Abstract

Background: A number of air pollutants have been consistently linked to chronic obstructive pulmonary disease including asthma which has emerged as the principal occupational infectious lung diseases. The first unique feature of DNA that was recognized as having taxonomic importance was its mole percent guanine plus cytosine content (Johanson, 1981). Among the bacteria, the mol% G+C values range from 25-75 and the value is constant for a given organism. Closely related bacteria have similar mol% G+C values. Methodology: Genomic DNA was extracted from 15 unknown bacterial isolates from respiratory systems of oil refinery workers and standard strain of Escherichia. coli mj83 (the mol % G + C of the DNA is: 50.9) as control by the salting-out. Results: Five samples were with high purity ranged between 1.7- 1.97, eight samples showed purity between 1.51- 1.61, two samples were 1.05 and 1.11 and one was 2.5. Conclusions: Three oxidative isolates showed low purity of DNA also showed unstable readings of UV absorbance at 260 nm, so that it was difficult to find the correct Tm for each of them. This might be due to presence of pollutants which interact with the absorbance of DNA at 260 nm.

Keywords: Bacteria, DNA G:C ratio, Oil refinery workers, Al-Baiji, Iraq.