Superoxide dismutase plays an important role in the survival of Lactobacillus sake upon exposure to elevated oxygen.
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.
Amanatidou
A
A
Agrotechnological Research Institute (ATO-B.V.), Bornsesteeg 59, 6708 PD, Wageningen, The Netherlands. athina.esveld@unilever.com
Bennik
M H
MH
Gorris
L G
LG
Smid
E J
EJ
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
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