TY - JOUR
T1 - Influence of cold shock on the fatty-acid composition of different lipid classes of the food-borne pathogen Listeria monocytogenes
AU - Mastronicolis, S. K.
AU - German, J. B.
AU - Megoulas, N.
AU - Petrou, E.
AU - Foka, P.
AU - Smith, G. M.
PY - 1998
Y1 - 1998
N2 - Listeria monocytogenes, a Gram-positive pathogenic food-borne bacterium, is notably resistant to chill and osmotic stress. Listeria is characterized by an unusual proportion of branched-chain fatty acid (>85%), primarily anteiso-15:0 and anteiso-17:0. Cells grown at lower temperatures contain significantly less anteiso-17:0 than those grown at higher temperature. Cold-shock studies were performed to determine the mechanisms by which Listeria perceives cold shock and changes its membrane composition. This study made three comparisons: (i) The lipids of L. monocytogenes cultured at 30°C were compared with those of cells grown at 6°C. Extraction of total lipids yielded 4-4.5 and 6.5-7 mg ml-1 cell mass (wet weight), respectively. Total lipids contained 3-4% and 2-2.5% lipid phosphorus, respectively, reflecting a higher content of neutral lipids in cells grown at 6°C. (ii) The fatty-acid compositions of different lipid classes (total lipids, the major phospholipid, and the glyco-containing phospholipid class) all responded by increasing the proportion of anteiso-15:0 fatty acids at low temperature. (iii) The fatty-acid composition of the neutral and polar lipids from the early stage of the temperature response (3 days at 5°C) and the effect of chloramphenicol or cerulenin were examined. The results indicated that anteiso-15:0 fatty acids were selectively increased in the newly synthesized neutral lipids, but the polar lipids did not show an apparent change in fatty-acid composition. These changes in membrane fatty-acid composition did not require new protein synthesis (the process was chloramphenicol insensitive) and the existing condensing enzyme activity was necessary to the fatty-acid response (the process was cerulenin sensitive).
AB - Listeria monocytogenes, a Gram-positive pathogenic food-borne bacterium, is notably resistant to chill and osmotic stress. Listeria is characterized by an unusual proportion of branched-chain fatty acid (>85%), primarily anteiso-15:0 and anteiso-17:0. Cells grown at lower temperatures contain significantly less anteiso-17:0 than those grown at higher temperature. Cold-shock studies were performed to determine the mechanisms by which Listeria perceives cold shock and changes its membrane composition. This study made three comparisons: (i) The lipids of L. monocytogenes cultured at 30°C were compared with those of cells grown at 6°C. Extraction of total lipids yielded 4-4.5 and 6.5-7 mg ml-1 cell mass (wet weight), respectively. Total lipids contained 3-4% and 2-2.5% lipid phosphorus, respectively, reflecting a higher content of neutral lipids in cells grown at 6°C. (ii) The fatty-acid compositions of different lipid classes (total lipids, the major phospholipid, and the glyco-containing phospholipid class) all responded by increasing the proportion of anteiso-15:0 fatty acids at low temperature. (iii) The fatty-acid composition of the neutral and polar lipids from the early stage of the temperature response (3 days at 5°C) and the effect of chloramphenicol or cerulenin were examined. The results indicated that anteiso-15:0 fatty acids were selectively increased in the newly synthesized neutral lipids, but the polar lipids did not show an apparent change in fatty-acid composition. These changes in membrane fatty-acid composition did not require new protein synthesis (the process was chloramphenicol insensitive) and the existing condensing enzyme activity was necessary to the fatty-acid response (the process was cerulenin sensitive).
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U2 - 10.1006/fmic.1997.0170
DO - 10.1006/fmic.1997.0170
M3 - Article
AN - SCOPUS:0032103572
VL - 15
SP - 299
EP - 306
JO - Food Microbiology
JF - Food Microbiology
SN - 0740-0020
IS - 3
ER -