In vitro antibacterial activity and antifungal mode of action of flocculosin, a membrane-active cellobiose lipid.
OBJECTIVE
To investigate the in vitro antibacterial activity and antifungal mode of action of flocculosin, a cellobiose lipid produced by Pseudozyma flocculosa.


RESULTS
When tested against clinical bacterial isolates, the compound was particularly active against Gram-positive bacteria and its effect was not mitigated against isolates known as resistant to other antibiotics. The antifungal activity of flocculosin was found to be rapid and concentration-dependent. At lethal concentrations against Candida albicans, flocculosin caused a rapid leakage of intracellular potassium and inhibited acidification of the medium by plasma membrane ATPases suggesting a physical rather than a biochemical effect. TEM observations of cells exposed 6 h to flocculosin revealed disrupted membranes and disorganized mitochondria.


CONCLUSIONS
Data obtained in this study confirm that flocculosin acts by disrupting the membrane surface of sensitive micro-organisms.


CONCLUSIONS
The elucidation of an antifungal mode of action of flocculosin can be exploited in furthering its antimicrobial potential against fungi and bacteria whose cell membranes are particularly sensitive to the action of the molecule.
Mimee
B
B
Centre de Recherche en Horticulture, Université Laval, Québec, Canada.
Pelletier
R
R
Bélanger
R R
RR
D000890:Anti-Infective Agents / Q000494:pharmacology*; D000935:Antifungal Agents / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects* / Q000378:metabolism / Q000648:ultrastructure; D002176:Candida albicans / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D002462:Cell Membrane / Q000187:drug effects; D002475:Cellobiose / Q000031:analogs & derivatives* / Q000494:pharmacology; D015169:Colony Count, Microbial; D006017:Glycolipids / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests / Q000379:methods; D046529:Microscopy, Electron, Transmission; D010940:Plant Proteins / Q000494:pharmacology; D011188:Potassium / Q000378:metabolism; D013997:Time Factors; D014587:Ustilaginales / Q000378:metabolism*
C476096:2-(2',4'-diacetoxy-5'-carboxypentanoyl)octadecylcellobioside; D000890:Anti-Infective Agents; D000935:Antifungal Agents; D006017:Glycolipids; D010940:Plant Proteins; D002475:Cellobiose; D011188:Potassium