Polymyxin B octapeptide and polymyxin B heptapeptide are potent outer membrane permeability-increasing agents.

Rhizobium strains differ considerably in outer membrane permeability and polymyxin B resistance.

Six rhizobium (Rhizobium leguminosarum bv. Trifolii TA1, Sinorhizobium meliloti 1021, Mesorhizobium huakuii IFO 15243(T), Ochrobactrum lupini LUP 21(T), Bradyrhizobium japonicum USDA110 and B. elkanii USDA 76) and two Escherichia coli strains (E. coli ATCC 25922 and E. coli HB 101) were compared in respect to polymyxin B and EDTA resistance, as well as bacterial outer membrane (OM) permeability...

Polymyxin b: controlled biosynthesis.

The polymyxins form a group of closely related strongly basic cyclicpeptide antibiotics with a rather specific activity against gram-negative bacteria. The most well-known and commercially produced members are poly-myxin B and E (colistin). These two consists of polymyxin B1, B2, B3 and E1, E2, E " the single components of them differing only in the fatty acid moiety of the side chain attached ...

Polymyxin B and heart muscle.

The effects of the polypeptide antibiotic, polymyxin B, on myocardial contractility were studied in t;e isolated rat heart muscle. Five different doses of polymyxin B were tested. There were no changes in contractility with does ranging from the clinical therapeutic value to three times greater. There was an initial increase and then depression with a dose six times greater than the therapeutic...

Chemical studies on polymyxin B.

The effect of polymyxin B on outer membrane of Serratia marcescens: activation and dissociation of outer membrane associated alkaline phosphatase.

Various reports have indicated that the cationic cyclic-peptide antibiotic, polymyxin B (PB), interacts with a number of outer membrane components of gram-negative bacteria1-5). PB degrades lipopolysaccharide (LPS)1,2) and phospholipids3) and forms complexes with these molecules4,5). Such effects appear to be due to a multiplicity of actions of this antibiotic. More recently, the PB degradation...