CO2- and anaerobiosis-induced changes in physiology and gene expression of different Listeria monocytogenes strains.
Although carbon dioxide (CO(2)) is known to inhibit growth of most bacteria, very little is known about the cellular response. The food-borne pathogen Listeria monocytogenes is characterized by its ability to grow in high CO(2) concentrations at refrigeration temperatures. We examined the listerial responses of different strains to growth in air, 100% N(2), and 100% CO(2). The CO(2)-induced changes in membrane lipid fatty acid composition and expression of selected genes were strain dependent. The acid-tolerant L. monocytogenes LO28 responded in the same manner to CO(2) as to other anaerobic, slightly acidic environments (100% N(2), pH 5.7). An increase in the expression of the genes encoding glutamate decarboxylase (essential for survival in strong acid) as well as an increased amount of branched-chain fatty acids in the membrane was observed in both atmospheres. In contrast, the acid-sensitive L. monocytogenes strain EGD responded differently to CO(2) and N(2) at the same pH. In a separate experiment with L. monocytogenes 412, an increased isocitrate dehydrogenase activity level was observed for cells grown in CO(2)-containing atmospheres. Together, our findings demonstrate that the CO(2)-response is a partly strain-dependent complex mechanism. The possible links between the CO(2)-dependent changes in isocitrate dehydrogenase activity, glutamate metabolism and branched fatty acid biosynthesis are discussed.
Jydegaard-Axelsen
Anne-Marie
AM
Department of Food Science, The Royal Veterinary and Agricultural University, Rolighedsvej 30, DK-1958 Frederiksberg, Denmark.
Høiby
Poul Erik
PE
Holmstrøm
Kim
K
Russell
Nicholas
N
Knøchel
Susanne
S
D000693:Anaerobiosis; D002245:Carbon Dioxide / Q000494:pharmacology*; D005227:Fatty Acids / Q000032:analysis / Q000096:biosynthesis; D015870:Gene Expression; D018698:Glutamic Acid / Q000378:metabolism; D007521:Isocitrate Dehydrogenase / Q000378:metabolism; D008089:Listeria monocytogenes / Q000235:genetics / Q000502:physiology*; D008563:Membrane Lipids / Q000032:analysis
D005227:Fatty Acids; D008563:Membrane Lipids; D002245:Carbon Dioxide; D018698:Glutamic Acid; D007521:Isocitrate Dehydrogenase