Polycations increase the permeability of Mycobacterium vaccae cell envelopes to hydrophobic compounds.
Polycations [protamine, polymyxin B nonapeptide (PMBN) and polyethyleneimine (PEI)] have been shown to increase the cell wall permeability of Mycobacterium vaccae to highly hydrophobic compounds, as manifested in enhanced intracellular bioconversion of beta-sitosterol to 4-androsten-3,17-dione (AD) and 1,4-androstadien-3,17-dione (ADD), and cell sensitization to erythromycin and rifampicin. The quantity of AD(D) formed per biomass unit was twice as high in the presence of PMBN and PEI, and three times higher with protamine. The sensitization factor, i.e. the MIC(50) ratio of the control bacteria to those exposed to polycations, ranged from 4 to 16, depending on the polycation/antibiotic combination. Non-covalently bound free lipids were extracted from the control and polycation-treated cells and fractionated with the use of chloroform, acetone and methanol. Chloroform- and acetone-eluted fractions (mainly neutral lipids and glycolipids, respectively) showed significant polycation-induced alterations in their quantitative and qualitative composition. The fatty acid profile of neutral lipids was reduced in comparison to control, whereas acetone-derived lipids were characterized by a much higher level of octadecenoic acid (C(18:1)) and a considerably lower content of docosanoic acid (C(22:0)), the marker compound of mycolate-containing glycolipids. Methanol-eluted fractions remained unaltered. Cell-wall-linked mycolates obtained from delipidated cells were apparently unaffected by the action of polycations, as judged from the TLC pattern of mycolic acid subclasses, the mean weight of mycolate preparations and the C(22:0) acid content in the mycolates, determined by GC/MS and pyrolysis GC. The results suggest the involvement of the components of non-covalently bound lipids in the outer layer in the M. vaccae permeability barrier.
Korycka-Machała
Małgorzata
M
Centre for Microbiology & Virology, Polish Academy of Sciences, 93-232 Łódź, Lodowa 106, Poland1.
Ziółkowski
Andrzej
A
Centre for Microbiology & Virology, Polish Academy of Sciences, 93-232 Łódź, Lodowa 106, Poland1.
Rumijowska-Galewicz
Anna
A
Centre for Microbiology & Virology, Polish Academy of Sciences, 93-232 Łódź, Lodowa 106, Poland1.
Lisowska
Katarzyna
K
University of Łódź, Institute of Microbiology and Immunology, Department of Industrial Microbiology, 90-237 Łódź, Banacha 12/16, Poland2.
Sedlaczek
Leon
L
Centre for Microbiology & Virology, Polish Academy of Sciences, 93-232 Łódź, Lodowa 106, Poland1.
D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002463:Cell Membrane Permeability / Q000187:drug effects*; D002473:Cell Wall / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism*; D004917:Erythromycin / Q000494:pharmacology; D005227:Fatty Acids / Q000032:analysis; D008826:Microbial Sensitivity Tests; D009161:Mycobacterium / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism*; D009171:Mycolic Acids / Q000032:analysis; D011073:Polyamines / Q000494:pharmacology*; D000071228:Polyelectrolytes; D012293:Rifampin / Q000494:pharmacology; D012855:Sitosterols / Q000378:metabolism; D013499:Surface Properties
D000900:Anti-Bacterial Agents; D004917:Erythromycin; D005227:Fatty Acids; D009171:Mycolic Acids; D011073:Polyamines; D000071228:Polyelectrolytes; D012293:Rifampin; D012855:Sitosterols; C025473:gamma-sitosterol