Membrane fatty acid composition as a determinant of Listeria monocytogenes sensitivity to trans-cinnamaldehyde.
trans-Cinnamaldehyde, the major compound of cinnamon essential oil, is a potentially interesting natural antimicrobial food preservative. Although a number of studies have addressed its mode of action, the factors that determine bacterial sensitivity or tolerance to trans-cinnamaldehyde are poorly understood. We report the detailed characterization of a Listeria monocytogenes Scott A trans-cinnamaldehyde hypersensitive mutant defective in IlvE, which catalyzes the reversible transamination of branched-chain amino acids to the corresponding short-chain α-ketoacids. This mutant showed an 8.4 fold extended lag phase during growth in sublethal concentrations (4 mM), and faster inactivation in lethal concentrations of trans-cinnamaldehyde (6 mM). trans-Cinnamaldehyde hypersensitivity could be corrected by genetic complementation with the ilvE gene and supplementation with branched-chain α-ketoacids. Whole-cell fatty acid analyses revealed an almost complete loss of anteiso branched-chain fatty acids (BCFAs), which was compensated by elevated levels of unbranched saturated fatty acids and iso-BCFAs. Sub-inhibitory concentrations of trans-cinnamaldehyde induced membrane fatty acid adaptations predicted to reduce membrane fluidity, possibly as a response to counteract the membrane fluidizing effect of trans-cinnamaldehyde. These results demonstrate the role of IlvE in BCFA production and the role of membrane composition as an important determinant of trans-cinnamaldehyde sensitivity in L. monocytogenes.
KU Leuven, Department of Microbial and Molecular Systems (M(2)S), Leuven Food Science and Nutrition Research Center (LFoRCe), Laboratory of Food Microbiology, Kasteelpark Arenberg 22, 3001 Leuven, Belgium. Electronic address: gil.rogiers@kuleuven.be.
Gil
G
Rogiers
KU Leuven, Department of Microbial and Molecular Systems (M(2)S), Leuven Food Science and Nutrition Research Center (LFoRCe), Laboratory of Food Technology, Kasteelpark Arenberg 22, 3001 Leuven, Belgium.
Biniam T
BT
Kebede
KU Leuven, Department of Microbial and Molecular Systems (M(2)S), Leuven Food Science and Nutrition Research Center (LFoRCe), Laboratory of Food Technology, Kasteelpark Arenberg 22, 3001 Leuven, Belgium.
Ann
A
Van Loey
KU Leuven, Department of Microbial and Molecular Systems (M(2)S), Leuven Food Science and Nutrition Research Center (LFoRCe), Laboratory of Food Microbiology, Kasteelpark Arenberg 22, 3001 Leuven, Belgium. Electronic address: chris.michiels@kuleuven.be.
Chris W
CW
Michiels
D000171:Acrolein / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology; D000597:Amino Acids, Branched-Chain / Q000032:analysis / Q000378:metabolism; D000890:Anti-Infective Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics; D002462:Cell Membrane / Q000737:chemistry* / Q000187:drug effects; D003470:Culture Media; D005227:Fatty Acids / Q000032:analysis* / Q000737:chemistry; D005520:Food Preservatives / Q000494:pharmacology; D005816:Genetic Complementation Test; D008089:Listeria monocytogenes / Q000737:chemistry* / Q000187:drug effects* / Q000235:genetics / Q000254:growth & development; D008560:Membrane Fluidity / Q000187:drug effects; D009154:Mutation
D000597:Amino Acids, Branched-Chain; D000890:Anti-Infective Agents; D001426:Bacterial Proteins; D003470:Culture Media; D005227:Fatty Acids; D005520:Food Preservatives; D000171:Acrolein; C012843:cinnamaldehyde
Amino acids; Antimicrobial agents; Branched chain; Food preservatives; Oils; Volatile