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Stress response of Salmonella Typhimurium to acidified nitrite

ABSTRACT: The antimicrobial action of the curing agent NaNO2, which is added as a preservative to raw meat products, depends on its conversion to nitric oxide and other reactive nitrogen species under acidic conditions. In this study, we applied RNA-sequencing to analyze the acidified NaNO2 shock and adaptive response of Salmonella Typhimurium, a frequent contaminant in raw meat. Upon a 10 minute exposure to 150 mg/l NaNO2 in LB pH 5.5 acidified with lactic acid, genes involved in nitrosative stress protection together with several other stress related genes were induced. To the contrary, genes involved in translation, transcription, replication and motility were down-regulated. Induction of stress tolerance and reduction of cell proliferation obviously promote survival under harsh acidified NaNO2 stress. The subsequent adaptive response was characterized by up-regulation of NsrR-regulated genes and iron-uptake systems and down-regulation of genes involved in anaerobic respiratory pathways. Strikingly, amino acid decarboxylase systems, which contribute to acid tolerance, displayed increased transcript levels in response to acidified NaNO2. The induction of systems known to be involved in acid resistance indicates a nitrite mediated increase of acid stress.

ORGANISM(S): Salmonella enterica subsp. enterica serovar Typhimurium

PROVIDER: GSE57238 | GEO | 2014/08/25

SECONDARY ACCESSION(S): PRJNA246027

REPOSITORIES: GEO

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Project description:Systems responses of mature leaves from 4 reference cultivars of a larger collection of European potato cultivars (Solanum tuberosum L.) are investigated by metabolome profiling and RNA-Sequencing. The chosen reference cultivars, Milva, Alegria, Desiree, and Saturna, vary in ascending order in regard to drought tolerance. Systems analyses are based on 3 independent field trials and 3 paralleled greenhouse trials. Robust responses across all cultivars and conditions to natural seasonal drought stress comprise proline, raffinose, galactinol, arabitol, arabinonic acid, chlorogenic acid, and 102 transcripts which consist to a high proportion of heat shock proteins and genes with signaling or regulatory functions, such as a homolog of abscisic acid receptor PYL4. Constitutive differences of the tolerant cultivars, Desiree and Saturna, compared to the sensitive cultivars include arbutin (hydroquinone-beta-D-glucopyranoside), octopamine (p-hydroxyphenylethanolamine), ribitol and 248 differential transcripts. Many of these transcripts are disease related, receptor kinases, or regulatory genes, for example a homolog of the Arabidopsis FOUR LIPS MYB-regulator of stomatal cell proliferation. Functional enrichment analyses imply that heat stress is a major acclimation component of potato leaves to agronomical relevant drought stress. Enhanced leaf heat stress is a result of drought caused by loss of transpiration cooling. This effect and CO2-limitation are the main dilemmas of drought- or ABA-induced stomatal closure. Constitutive differences between tolerant and sensitive cultivars indicate partially synergistic interactions of drought and biotic stress responses. We suggest that drought tolerance of the potato reference cultivars may be caused by general resistance mechanisms which are part of previously selected pathogen tolerance. Transcriptome profiling by RNA-sequencing of 48 leaf samples from 4 potato cultivars grown under control or drought stress conditions in 6 independent experiments

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Stress response of Salmonella Typhimurium to acidified nitrite

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