Nisin induces changes in membrane fatty acid composition of Listeria monocytogenes nisin-resistant strains at 10 degrees C and 30 degrees C.
Listeria monocytogenes isolates resistant to 10(5) IU ml-1 nisin were obtained at 30 degrees C (NR30) and at 10 degrees C (NR10). Nisin prolonged the lag phase of isolate NR30 at 10 degrees C. Isolates NR30 and NR10 did not produce a nisinase. Protoplasts of isolate NR30 were unaffected by exposure to nisin. The fatty acid composition from the wild-type strain and NR isolates was determined. As expected, temperature-induced differences in the C15/C17 fatty acid ratios were found. Growth of the NR strains in the presence of nisin resulted in significantly different C15/C17 ratios and a significant increase in the percentage of C16:0, C16: 1, C18:0 and C18: 1 fatty acids at 10 degrees C and 30 degrees C. Both the NR10 and NR30 isolates had similar growth rates at low temperatures, but these were slower than the wild-type strain. These results indicate that 'nisin resistance' is an environmentally defined phenotype and that nisin induces changes in the fatty acid composition of the membrane in L. monocytogenes nisin-resistant isolates regardless of the growth temperature.
Mazzotta
A S
AS
Department of Food Science, New Jersey Agricultural Experiment Station, Cook College, Rutgers, State University of New Jersey, New Brunswick 08903, USA.
Montville
T J
TJ
D000362:Agar; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002462:Cell Membrane / Q000737:chemistry / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004352:Drug Resistance, Microbial; D004578:Electron Spin Resonance Spectroscopy; D005227:Fatty Acids / Q000378:metabolism*; D008089:Listeria monocytogenes / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D008560:Membrane Fluidity / Q000187:drug effects; D009561:Nisin / Q000494:pharmacology*; D013696:Temperature
D000900:Anti-Bacterial Agents; D005227:Fatty Acids; D009561:Nisin; D000362:Agar