A novel method for isolation new strain of E. coli ( resist for cloxacillin acillin and sensitive to Ampicillin. ) and other strain(sensitive for Cloxacillin acillin and resist to Ampicillin.) and check it’s transformation with isolated plasmid and it’s stability by serial plating method

Mohammed Abdul Rahmman Mohammed

Department of biology   -College of science – Baghdad University –  Baghdad –  Iraq

Abstract

Bacterial strains ( E. coli ) were collected from two different places , The first strain was collected from central Laboratory – Baghdad university , meanwhile the second strain was collected from  pathogenic laboratory – Baghdad university

Replica plating and gradient plate method technique were used to prepare strains with different multi trails

Replica plating was used to select strain resist to specific antibiotic with low concentration ( sensitive for other type of antibiotic )  then go head subsequently with gradient plate method to adapt the strain to resist (high concentration )

Replica plating was used to select first strain resist to Ampicillin. ( 100 Mg- ml ) and ( sensitive to Cloxacillin ..)  then gradient plate method was used to adapt first strain to resist Ampicillin.  (500 Mg-ml ) therefore. first strain was resistant to Ampicillin. ( 500 Mg- ml ) and sensitive to Cloxacillin (500 Mg- ml )  , on other hand ,by using same methods  , second strain was resistant to Cloxacillin ( 500 Mg- ml ) and sensitive to Ampicillin.. (500 Mg- ml ) Replica plating was used to select third strain sensitive to Ampicillin. and Cloxacillin .( 500 Mg- ml ) for each type of antibiotics and it is consider as competent cell . To visualize if ( Ampicillin. resist trail and Cloxacillin resist trail  ) carried  on plasmid , first , second and third strains were transformed by using transformation technique

The Transformant  strain was resistant to ( 1000 Mg- ml ) by which resist to Ampicillin. and  Cloxacillin . (500 Mg –ml ) for each antibiotic .

The efficiency of transformation was determined as percentage of transformation ,  it was so high a round ( 9% )

The Transformant strain was checked for stability of it’s plasmid by using sub – culturing method . It was stable for 12 times of sub culturing of transformant growth

Concentration of the protein for E. coli  ( resist for cloxacillin and sensitive to Ampicillin. ) and other strain(sensitive for Cloxacillin acillin and resist to Ampicillin.) was 0.065 and 0.116 meanwhile transformant was 0.190

Finally , . using replica plating ,  gradient plate and transformation process consider as a novel technique to prepare strains  with multi trails  which  resist  very high concentration of antibiotics and

efficient transformation process . 

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