Thioredoxin reductase is a key factor in the oxidative stress response of Lactobacillus plantarumWCFS1

Serrano, Molenaar Douwe, Wels Michiel, Teusink Bas, Bron, De, Smid

Description

Thioredoxin (TRX) is a powerful disulfide oxido-reductase that catalyzes a wide spectrum of redox reactions in the cell. The aim of this study is to elucidate the role of the TRX system in the oxidative stress response in Lactobacillus plantarum WCFS1. Results We have identified the trxB1 -encoded thioredoxin reductase (TR) as a key enzyme in the oxidative stress response of Lactobacillus plantarum WCFS1. Overexpression of the trxB1 gene resulted in a 3-fold higher TR activity in comparison to the wild-type strain. Subsequently, higher TR activity was associated with an increased resistance towards oxidative stress. We further determined the global transcriptional response to hydrogen peroxide stress in the trxB1 -overexpression and wild-type strains grown in continuous cultures. Hydrogen peroxide stress and overproduction of TR collectively resulted in the up-regulation of 267 genes. Additionally, gene expression profiling showed significant differential expression of 27 genes in the trxB1 -overexpression strain. Over expression of trxB1 was found to activate genes associated with DNA repair and stress mechanisms as well as genes associated with the activity of biosynthetic pathways for purine and sulfur-containing amino acids. A total of 16 genes showed a response to both TR overproduction and hydrogen peroxide stress. These genes are involved in the purine metabolism, energy metabolism ( gapB ) as well as in stress-response ( groEL , npr2 ), and manganese transport ( mntH2 ). Conclusion Based on our findings we propose that overproduction of the trxB1 -encoded TR in L. plantarum improves tolerance towards oxidative stress. This response coincides with simultaneous induction of a group of 16 transcripts of genes. Within this group of genes, most are associated with oxidative stress response. The obtained crossover between datasets may explain the phenotype of the trxB1 -overexpression strain, which appears to be prepared for encountering oxidative stress. This latter property can be used for engineering robustness towards oxidative stress in industrial strains of L. plantarum .

Informations

• Publié par: biomed
• Publié le: 01 janvier 2007
• Nombre de lectures: 11
• Langue: English

Extrait

Microbial Cell Factories

BioMedCentral

Open Access Research Thioredoxin reductase is a key factor in the oxidative stress response ofLactobacillus plantarumWCFS1 1,2,3 1,2 1 1,2 L Mariela Serrano , Douwe Molenaar , Michiel Wels , Bas Teusink , 1 1,3 1,2 Peter A Bron , Willem M de Vos and Eddy J Smid*

1 2 Address: Top Institute Food and Nutrition, formerly WCFS, Wageningen, The Netherlands, NIZO Food Research B.V., Ede, The Netherlands and 3 Wageningen UR, Laboratory of Microbiology, Wageningen, The Netherlands Email: L Mariela Serrano  [e-mail]; Douwe Molenaar  [e-mail]; Michiel Wels  [e-mail]; Bas Teusink  [e-mail]; Peter A Bron  [e-mail]; Willem M de Vos  [e-mail]; Eddy J Smid*  [e-mail] * Corresponding author

Published: 28 August 2007 Received: 2 July 2007 Accepted: 28 August 2007 Microbial Cell Factories2007,6:29 doi:10.1186/1475-2859-6-29 This article is available from: http://www.microbialcellfactories.com/content/6/1/29 © 2007 Serrano et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract Background:Thioredoxin (TRX) is a powerful disulfide oxido-reductase that catalyzes a wide spectrum of redox reactions in the cell. The aim of this study is to elucidate the role of the TRX system in the oxidative stress response inLactobacillus plantarumWCFS1.

Results:We have identified thetrxB1-encoded thioredoxin reductase (TR) as a key enzyme in the oxidative stress response ofLactobacillus plantarumWCFS1.

Overexpression of thetrxB1gene resulted in a 3-fold higher TR activity in comparison to the wild- type strain. Subsequently, higher TR activity was associated with an increased resistance towards oxidative stress. We further determined the global transcriptional response to hydrogen peroxide stress in thetrxB1-overexpression and wild-type strains grown in continuous cultures. Hydrogen peroxide stress and overproduction of TR collectively resulted in the up-regulation of 267 genes. Additionally, gene expression profiling showed significant differential expression of 27 genes in the trxB1-overexpression strain. Over expression oftrxB1was found to activate genes associated with DNA repair and stress mechanisms as well as genes associated with the activity of biosynthetic pathways for purine and sulfur-containing amino acids. A total of 16 genes showed a response to both TR overproduction and hydrogen peroxide stress. These genes are involved in the purine metabolism, energy metabolism (gapB) as well as in stress-response (groEL,npr2), and manganese transport (mntH2).

Conclusion:Based on our findings we propose that overproduction of thetrxB1-encoded TR in L. plantarumimproves tolerance towards oxidative stress. This response coincides with simultaneous induction of a group of 16 transcripts of genes. Within this group of genes, most are associated with oxidative stress response. The obtained crossover between datasets may explain the phenotype of thetrxB1-overexpression strain, which appears to be prepared for encountering oxidative stress. This latter property can be used for engineering robustness towards oxidative stress in industrial strains ofL. plantarum.

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