Abstract
During the period January/ 01/ 2012 to February /02 /2013, hundred fifty soil samples were collected from Draia, Nasiria and Umalhamaam, Riyadh Saudi Arabia. Soil suspension was obtained by using pyrophosphate to separate soil particles. Small amount of soil (0.3g) were centrifuged at 5000 g/min for 10 minutes. Serial dilution and plating on nutrient agar solid medium suitable to the bacteria was adopted. In order to obtain DNA from bacterial soil, we used a method based on direct lysis of cells. Many methods have been described for isolating DNA from prokaryotic cells. The choice of method depends on the degree of the purity of the DNA required for the analysis to be performed. We have adopted simple and rapid method allowing DNA to be released from bacterial cells. In general, techniques with extraction kits were easily and rapidly performed but were more expensive than the manually prepared in our laboratory. DNA was released from bacterial cells by an organic method and alcohol precipitation was followed and was electrophoresed. Gram, single staining and sensitivity test of bacterial colonies from soil against some antibiotics were also performed.