title: Transcriptome analysis of Bifidobacterium longum strains that show a differential response to hydrogen peroxide stress.
abstract: Consumer and commercial interest in foods containing probiotic bifidobacteria is increasing. However, because bifidobacteria are anaerobic, oxidative stress can diminish cell viability during production and storage of bioactive foods. We previously found Bifidobacterium longum strain NCC2705 had significantly greater intrinsic and inducible resistance to hydrogen peroxide (H2O2) than strain D2957. Here, we explored the basis for these differences by examining the transcriptional responses of both strains to sub-lethal H2O2 exposure for 5- or 60-min. Strain NCC2705 had 288 genes that were differentially expressed after the 5-min treatment and 114 differentially expressed genes after the 60-min treatment. In contrast, strain D2957 had only 21 and 90 differentially expressed genes after the 5- and 60-min treatments, respectively. Both strains showed up-regulation of genes coding enzymes implicated in oxidative stress resistance, such as thioredoxin, thioredoxin reductase, peroxiredoxin, ferredoxin, glutaredoxin, and anaerobic ribonucleotide reductase, but induction levels were typically highest in NCC2705. Compared to D2957, NCC2705 also had more up-regulated genes involved in transcriptional regulation and more down-regulated genes involved in sugar transport and metabolism. These results provide a greater understanding of the molecular basis for oxidative stress resistance in B. longum and the factors that contribute to strain-to-strain variability in survival in bioactive food products.
authors: Department of Nutrition, Dietetics and Food Sciences, Utah State University, 8700 Old Main Hill, Logan, UT 84322-8700, USA. Electronic address: taylor.oberg@aggiemail.usu.edu.
authors: Taylor S
authors: TS
authors: Oberg
authors: Department of Nutrition, Dietetics and Food Sciences, Utah State University, 8700 Old Main Hill, Logan, UT 84322-8700, USA.
authors: Robert E
authors: RE
authors: Ward
authors: Department of Food Science, University of Wisconsin, 1605 Linden Drive, Madison, WI 53706-1565, USA.
authors: James L
authors: JL
authors: Steele
authors: Department of Nutrition, Dietetics and Food Sciences, Utah State University, 8700 Old Main Hill, Logan, UT 84322-8700, USA.
authors: Jeff R
authors: JR
authors: Broadbent
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics*; D001644:Bifidobacterium / Q000235:genetics*; D002462:Cell Membrane / Q000378:metabolism; D004269:DNA, Bacterial / Q000235:genetics; D005227:Fatty Acids / Q000378:metabolism; D015870:Gene Expression / Q000187:drug effects; D020869:Gene Expression Profiling; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D020411:Oligonucleotide Array Sequence Analysis; D016877:Oxidants / Q000494:pharmacology*; D018384:Oxidative Stress / Q000235:genetics*; D013045:Species Specificity
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D005227:Fatty Acids; D016877:Oxidants; D006861:Hydrogen Peroxide
keywords: Bifidobacterium longum; Oxidative stress; Probiotics