scholarly journals Lactococcus lactis Mutants Obtained From Laboratory Evolution Showed Elevated Vitamin K2 Content and Enhanced Resistance to Oxidative Stress

2021 ◽  
Vol 12 ◽  
Author(s):  
Yue Liu ◽  
Anteun de Groot ◽  
Sjef Boeren ◽  
Tjakko Abee ◽  
Eddy J. Smid
Keyword(s):  
Oxidative Stress ◽  
Lactococcus Lactis ◽  
Stress Resistance ◽  
Culture Media ◽  
Stress Protein ◽  
Vitamin K2 ◽  
Original Strain ◽  
Laboratory Evolution ◽  
Oxidative Stress Resistance ◽  
Propagation Regime

Vitamin K2 is an important vitamin for human health. Vitamin K2 enrichment in the human diet is possible by using vitamin K2-producing bacteria such as Lactococcus lactis in food fermentations. Based on previous observations that aerated cultivation conditions improved vitamin K2 content in L. lactis, we performed laboratory evolution on L. lactis MG1363 by cultivating this strain in a shake flask in a sequential propagation regime with transfers to a fresh medium every 72h. After 100 generations of propagation, we selected three evolved strains that showed improved stationary phase survival in oxygenated conditions. In comparison to the original strain MG1363, the evolved strains showed 50–110% increased vitamin K2 content and exhibited high resistance against hydrogen peroxide-induced oxidative stress. Genome sequencing of the evolved strains revealed common mutations in the genes ldh and gapB. Proteomics analysis revealed overproduction of glyceraldehyde 3-phosphate dehydrogenase (GapA), universal stress protein A2 (UspA2), and formamidopyrimidine-DNA glycosylase (MutM) under aerated conditions in evolved strains, proteins with putative functions in redox reactions, universal stress response, and DNA damage repair, all of which could contribute to the enhanced oxidative stress resistance. The mechanisms underlying elevated vitamin K2 content in the evolved strains remain to be elucidated. Two out of the three evolved strains performed similar to the original strain MG1363 in terms of growth and acidification of culture media. In conclusion, this study demonstrated a natural selection approach without genetic manipulations to obtain vitamin K2 overproducers that are highly relevant for food applications and contributed to the understanding of oxidative stress resistance in L. lactis.

scholarly journals Differential Roles of the Universal Stress Proteins of Escherichia coli in Oxidative Stress Resistance, Adhesion, and Motility

2005 ◽  
Vol 187 (18) ◽  
pp. 6265-6272 ◽  
Author(s):  
Laurence Nachin ◽  
Ulf Nannmark ◽  
Thomas Nyström
Keyword(s):  
Oxidative Stress ◽  
Escherichia Coli ◽  
Stress Resistance ◽  
Stress Proteins ◽  
Stress Protein ◽  
Physiological Role ◽  
Cellular Growth ◽  
Yeast Cells ◽  
Phenotypic Characterization ◽  
Oxidative Stress Resistance

ABSTRACT The universal stress protein (UspA) superfamily encompasses a conserved group of proteins that are found in bacteria, archaea, and eukaryotes. Escherichia coli harbors six usp genes—uspA, -C, -D, -E, -F, and -G—the expression of which is triggered by a large variety of environmental insults. The uspA gene is important for survival during cellular growth arrest, but the exact physiological role of the Usp proteins is not known. In this work we have performed phenotypic characterization of mutants with deletions of the six different usp genes. We report on hitherto unknown functions of these genes linked to motility, adhesion, and oxidative stress resistance, and we show that usp functions are both overlapping and distinct. Both UspA and UspD are required in the defense against superoxide-generating agents, and UspD appears also important in controlling intracellular levels of iron. In contrast, UspC is not involved in stress resistance or iron metabolism but is essential, like UspE, for cellular motility. Electron microscopy demonstrates that uspC and uspE mutants are devoid of flagella. In addition, the function of the uspC and uspE genes is linked to cell adhesion, measured as FimH-mediated agglutination of yeast cells. While the UspC and UspE proteins promote motility at the expense of adhesion, the UspF and UspG proteins exhibit the exact opposite effects. We suggest that the Usp proteins have evolved different physiological functions that reprogram the cell towards defense and escape during cellular stress.

scholarly journals Role of rgsA in Oxidative Stress Resistance in Pseudomonas aeruginosa

2021 ◽  
Author(s):  
Shuyi Hou ◽  
Jiaqin Zhang ◽  
Xiaobo Ma ◽  
Qiang Hong ◽  
Lili Fang ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Pseudomonas Aeruginosa ◽  
Stress Resistance ◽  
Oxidative Stress Resistance

Functional characterization of a mycothiol peroxidase in Corynebacterium glutamicum that uses both mycoredoxin and thioredoxin reducing systems in the response to oxidative stress

2015 ◽  
Vol 469 (1) ◽  
pp. 45-57 ◽  
Author(s):  
Meiru Si ◽  
Yixiang Xu ◽  
Tietao Wang ◽  
Mingxiu Long ◽  
Wei Ding ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Corynebacterium Glutamicum ◽  
Stress Resistance ◽  
Functional Characterization ◽  
Gram Positive ◽  
Oxidative Stress Resistance ◽  
Proton Donors ◽  
New Type ◽  
And Oxidative Stress

Mycothiol peroxidase, a new type of GSH peroxidase distributed in GSH-lacking high-(G+C)-content Gram-positive actinobacteria, uses both mycoredoxin and thioredoxin systems as proton donors for regeneration and oxidative stress resistance.

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