Bacterium Bacillus polymyxa

Bacterium Bacillus polymyxa Nutrient medium Corn meal... 

Polymyxins are antibiotics produced by the bacterium Bacillus polymyxa. They are protein derivatives having one end that is hydrophobic because of an attached fatty add. The opposite end is hydrophilic. Because of these properties, the polymyxins bind to membranes with the hydrophobic end embedded within the membrane, while the hydrophihc end remains outside the cell. As a result, the integrity of the membrane is disrupted, and leakage of cellular constituents occurs, causing cell death. 

Polymyxin B was first isolated from the bacterium Bacillus polymyxa in 1947. 

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