CONTROL OF MOS BY ANTIBIOTICS...

2). DAMAGE TO CYTOPLASMIC MEMBRANE:

                                                             Certain antibiotics produced by Bacillus spp can cause the damage to cytoplasmic membrane & cause leakage from the cytoplasmic membrane of the cell. The antibiotics included are Polymyxins, Gramicidins, Tyrocidine, Polyenes .http://www.ncbi.nlm.nih.gov/pubmed/15508894
http://pathmicro.med.sc.edu/mayer/antibiot.htm

http://voices.yahoo.com/antibiotics-four-ways-they-inhibit-microorganisms-2914969.html?cat=





Mechanism of Action:


 

After binding to lipopolysaccharide (LPS) in the outer membrane of Gram-negative bacteria, polymyxins disrupt both the outer and inner membranes. The hydrophobic tail is important in causing membrane damage, suggesting a detergent-like mode of action.
Removal of the hydrophobic tail of polymyxin B yields polymyxin nonapeptide, which still binds to LPS but no longer kills the bacterial cell. However, it still detectably increases the permeability of the bacterial cell wall to other antibiotics, indicating that it still causes some degree of membrane disorganization.
Gram-negative bacteria can develop resistance to polymyxins through various modifications of the LPS structure that inhibit the binding of polymyxins to LPS.
To know more visit this link: http://en.wikipedia.org/wiki/Gramicidin

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