The Correlation between NaCl Adaptation and Heat Sensitivity of Listeria monocytogenes, a Foodborne Pathogen through Fresh and Processed Meat.
This study examined the relationship between NaCl sensitivity and stress response of Listeria monocytogenes. Nine strains of L. monocytogenes (NCCP10805, NCCP10806, NCCP10807, NCCP10808, NCCP10809, NCCP10810, NCCP10811, NCCP10920 and NCCP 10943) were exposed to 0%, 1%, 2% and 4% NaCl, and then incubated at 60℃ for 60 min to select strains that were heat-sensitized (HS) and non-sensitized (NS) by NaCl exposure. After heat challenge, L. monocytogenes strains were categorized as HS (NCCP 10805, NCCP10806, NCCP10807, NCCP10810, NCCP10811 and NCCP10920) or NS (NCCP10808, NCCP10809 and NCCP10943). Total mRNA was extracted from a HS strain (NCCP10811) and two NS strains (NCCP10808 and NCCP10809), and then cDNA was prepared to analyze the expression of genes (inlA, inlB, opuC, betL, gbuB, osmC and ctc) that may be altered in response to NaCl stress, by qRT-PCR. The expression levels of two invasion-related genes (inlA and inlB) and two stress response genes (opuC and ctc) were increased (p<0.05) in NS strains after NaCl exposure in an NaCl concentration-dependent manner. However, only betL expression was increased (p<0.05) in the HS strains. These results indicate that the effect of NaCl on heat sensitization of L. monocytogenes is strain dependent and that opuC and ctc may prevent NS L. monocytogenes strains from being heat sensitized by NaCl. Moreover, NaCl also increases the expression of invasion-related genes (inlA and inlB).
Department of Food and Nutrition, Sookmyung Women's University, Seoul 04310, Korea.
Jeeyeon
J
Lee
Department of Food and Nutrition, Sookmyung Women's University, Seoul 04310, Korea.
Jimyeong
J
Ha
Department of Food and Nutrition, Sookmyung Women's University, Seoul 04310, Korea.
Sejeong
S
Kim
Department of Food and Nutrition, Sookmyung Women's University, Seoul 04310, Korea.
Soomin
S
Lee
Department of Food and Nutrition, Sookmyung Women's University, Seoul 04310, Korea.
Heeyoung
H
Lee
Department of Food and Nutrition, Sookmyung Women's University, Seoul 04310, Korea.
Yohan
Y
Yoon
Department of Oral Mcirobiology, College of Dentistry, Wonkwang University, Iksan 54538, Korea.
Kyoung-Hee
KH
Choi
Listeria monocytogenes; NaCl; heat sensitivity; invasion gene; transcriptome