Recherche et identification des enzymes de restriction produites par les bactéries isolées des échantillons collectés dans un marécage de la localité d'Emana vallée (Yaoundé)

Abstract

Bacteria are single-celled microorganisms with variable morphology. They can be isolated from soil, fresh water, air, skin etc. These microorganisms produce enzymes called restriction enzymes that cut double stranded DNA. Restriction enzymes provide a bacterium with the defense system especially against the DNA of the infecting virus. They recognize specific sites on the DNA molecule and cut the double strand either at the recognition site or few nucleotides away. Because of their properties, they are commonly used for manipulating DNA in the laboratory and are an essential tool in the realization of molecular cloning process in various fields. The aim of our work was to identify restriction enzymes produced by some bacterial isolated. To achieve this goal we collected samples of mud, stagnant water, leaves, sand and earth into a swamp of the resort of Emana Valley. These samples were cultivated in solid and liquid media for isolation of the different colonies. After this step, the restriction enzymes produced by the bacteria were identified thanks to optimization reactions, double digestion and mapping. We isolated a total of 32 kinds of bacteria from which 7 isolates produced an identifiable enzymatic activity (isolates R5, R7 and R10 from mud sample, R21 from leave samples, R26 from sand samples and R28 and R32 from soil samples). Comparing the profiles obtained with the known digestion models enabled us to identify the enzyme produced by isolate R5 as AvaII isoschizomer, R7 as BpmI isoschizomer, R10 as BstEII isoschizomer, R21 as EarI isoschizomer, R26 as HaeIII isoschizomer, R28 as HpaII isoschizomer and R32 as MboI isoschizomer. Other isolates did not produce identifiable enzyme activity. These activities will enrich the Cameroonian collection. The study of restriction enzymes is of capital importance in genetic engineering to isolate one or more genes in order to understand its function.