title: Superoxide dismutase plays an important role in the survival of Lactobacillus sake upon exposure to elevated oxygen.
abstract: In this study, the responses of two Lactobacillus sake strains to elevated oxygen concentrations at 8 degrees C were investigated. L. sake DSM 6333 (L. sake(sens)), unlike L. sake NCFB 2813 (L. sake(ins)), showed a low growth rate in the presence of 90% O(2) and a rapid loss in viability shortly after entry into stationary phase. The steady-state cytosolic superoxide radical (O(2)(-)) concentration in L. sake(sens) was 0.134 microM and in the oxygen-insensitive mutant LSUV4 it was 0.013 microM. The nine- to ten-fold decrease in the rate of O(2)(-) elimination in L. sake(sens) indicates the significance of the O(2)(-)-scavenging system in protecting against elevated O(2). The superoxide dismutase (SOD) activity was 10- to 20-fold higher in L. sake(ins) than in L. sake(sens), depending on the growth phase. An oxygen-insensitive mutant of L. sake(sens), designated as strain LSUV4, had a ten-fold higher SOD activity than the wild-type strain, which likely restored its oxygen tolerance. Damage to proteins in L. sake(sens) was evidenced by the increased protein carbonyl content and reduced activities of the [Fe-S]-cluster-containing enzymes fumarase and fumarate reductase. This study forms a physiological basis for understanding the significance of elevated oxygen stress as an additional method for inhibition of microbial growth in relation to food preservation.
authors.affiliation: Agrotechnological Research Institute (ATO-B.V.), Bornsesteeg 59, 6708 PD, Wageningen, The Netherlands. athina.esveld@unilever.com
authors.forename: A
authors.initials: A
authors.lastname: Amanatidou
authors.forename: M H
authors.initials: MH
authors.lastname: Bennik
authors.forename: L G
authors.initials: LG
authors.lastname: Gorris
authors.forename: E J
authors.initials: EJ
authors.lastname: Smid
mesh_terms: D000975:Antioxidants / Q000378:metabolism; D001426:Bacterial Proteins / Q000378:metabolism; D002455:Cell Division / Q000187:drug effects; D002462:Cell Membrane / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism; D005182:Flavin-Adenine Dinucleotide / Q000378:metabolism; D019746:Intramolecular Oxidoreductases / Q000378:metabolism; D007700:Kinetics; D007778:Lactobacillus / Q000166:cytology* / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D009243:NAD / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects; D010100:Oxygen / Q000378:metabolism* / Q000494:pharmacology; D013385:Succinate Dehydrogenase / Q000378:metabolism; D013482:Superoxide Dismutase / Q000235:genetics / Q000378:metabolism*; D013481:Superoxides / Q000378:metabolism
chemical_list: D000975:Antioxidants; D001426:Bacterial Proteins; D009243:NAD; D013481:Superoxides; D005182:Flavin-Adenine Dinucleotide; D013482:Superoxide Dismutase; D013385:Succinate Dehydrogenase; D019746:Intramolecular Oxidoreductases; C048474:oxaloacetate tautomerase; D010100:Oxygen