The Molecular Mechanism of Regulation of the NhaA Na
 +
 /H
 +
 Antiporter of
 Escherichia Coli
 , a key Transporter in the Adaptation to Na
 +
 and H
 +

Padan, Etana; Gerchman, Yoram; Rimon, Abraham; Rothman, Andrea; Dover, Nir; Carmel-Harel, Orna

doi:10.1002/9780470515631.ch12

Cited by 13 publications

(10 citation statements)

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“…A number of genes involved in the formation of Fe-S clusters (including iscA, iscS, and fdx), as well as the manganese superoxide dismutase gene sodA, which are induced under iron-limiting conditions (37,38), were also upregulated. The nhaA gene, which encodes a Na ϩ /H ϩ antiporter, was upregulated; this antiporter is associated with high-salinity environments and is used by bacteria to remove excess sodium from the cell (39).…”

Section: Resultsmentioning

confidence: 99%

ProP Is Required for the Survival of Desiccated Salmonella enterica Serovar Typhimurium Cells on a Stainless Steel Surface

Finn

Händler

Condell

et al. 2013

Appl Environ Microbiol

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dConsumers trust commercial food production to be safe, and it is important to strive to improve food safety at every level. Several outbreaks of food-borne disease have been caused by Salmonella strains associated with dried food. Currently we do not know the mechanisms used by Salmonella enterica serovar Typhimurium to survive in desiccated environments. The aim of this study was to discover the responses of S. Typhimurium ST4/74 at the transcriptional level to desiccation on a stainless steel surface and to subsequent rehydration. Bacterial cells were dried onto the same steel surfaces used during the production of dry foods, and RNA was recovered for transcriptomic analysis. Subsequently, dried cells were rehydrated and were again used for transcriptomic analysis. A total of 266 genes were differentially expressed under desiccation stress compared with a static broth culture. The osmoprotectant transporters proP, proU, and osmU (STM1491 to STM1494) were highly upregulated by drying. Deletion of any one of these transport systems resulted in a reduction in the long-term viability of S. Typhimurium on a stainless steel food contact surface. The proP gene was critical for survival; proP deletion mutants could not survive desiccation for long periods and were undetectable after 4 weeks. Following rehydration, 138 genes were differentially expressed, with upregulation observed for genes such as proP, proU, and the phosphate transport genes (pstACS). In time, this knowledge should prove valuable for understanding the underlying mechanisms involved in pathogen survival and should lead to improved methods for control to ensure the safety of intermediate-and low-moisture foods.

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Section: Resultsmentioning

confidence: 99%

ProP Is Required for the Survival of Desiccated Salmonella enterica Serovar Typhimurium Cells on a Stainless Steel Surface

Finn

Händler

Condell

et al. 2013

Appl Environ Microbiol

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“…The membrane-bound Na ϩ /H ϩ antiporter encoded by nhaA is the main E. coli system responsible for adaptation to Na ϩ and alkaline pH (in the presence of Na ϩ ) (28). Based on the transcriptome data presented here, the S. oneidensis nhaA gene product likely plays a major role in the cellular response to alkaline pH.…”

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confidence: 83%

Transcriptome Profiling of Shewanella oneidensis Gene Expression following Exposure to Acidic and Alkaline pH

et al. 2006

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The molecular response of Shewanella oneidensis MR-1 to variations in extracellular pH was investigated based on genomewide gene expression profiling. Microarray analysis revealed that cells elicited both general and specific transcriptome responses when challenged with environmental acid (pH 4) or base (pH 10) conditions over a 60-min period. Global responses included the differential expression of genes functionally linked to amino acid metabolism, transcriptional regulation and signal transduction, transport, cell membrane structure, and oxidative stress protection. Response to acid stress included the elevated expression of genes encoding glycogen biosynthetic enzymes, phosphate transporters, and the RNA polymerase sigma-38 factor (rpoS), whereas the molecular response to alkaline pH was characterized by upregulation of nhaA and nhaR, which are predicted to encode an Na ؉ /H ؉ antiporter and transcriptional activator, respectively, as well as sulfate transport and sulfur metabolism genes. Collectively, these results suggest that S. oneidensis modulates multiple transporters, cell envelope components, and pathways of amino acid consumption and central intermediary metabolism as part of its transcriptome response to changing external pH conditions.

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“…The strategies include: (i) increased metabolic acid production through amino acid deaminases and sugar fermentation; (ii) increased ATP synthase that couples H + entry to ATP generation; (iii) changes in cell surface properties and (iv) increased expression and activity of monovalent cation/proton antiporters. Among these strategies, monovalent cation/proton antiporters play an essential and dominant role in alkaline pH homeostasis in many bacteria in addition to roles in Na + and volume homeostasis [3,[35][36][37][38][39][40][41] Similarly, Na + /H + antiporters play essential roles in homeostasis of pH, Na + and volume in eukaryotic cells and organelles [37,[42][43][44][45].…”

Section: Introductionmentioning

confidence: 99%

Alkaline pH homeostasis in bacteria: New insights

Padan

Bibi

Ito

et al. 2005

Biochimica et Biophysica Acta (BBA) - Biomembranes

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684

633

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The capacity of bacteria to survive and grow at alkaline pH values is of widespread importance in the epidemiology of pathogenic bacteria, in remediation and industrial settings, as well as in marine, plant-associated and extremely alkaline ecological niches. Alkali-tolerance and alkaliphily, in turn, strongly depend upon mechanisms for alkaline pH homeostasis, as shown in pH shift experiments and growth experiments in chemostats at different external pH values. Transcriptome and proteome analyses have recently complemented physiological and genetic studies, revealing numerous adaptations that contribute to alkaline pH homeostasis. These include elevated levels of transporters and enzymes that promote proton capture and retention (e.g., the ATP synthase and monovalent cation/proton antiporters), metabolic changes that lead to increased acid production, and changes in the cell surface layers that contribute to cytoplasmic proton retention. Targeted studies over the past decade have followed up the long-recognized importance of monovalent cations in active pH homeostasis. These studies show the centrality of monovalent cation/proton antiporters in this process while microbial genomics provides information about the constellation of such antiporters in individual strains. A comprehensive phylogenetic analysis of both eukaryotic and prokaryotic genome databases has identified orthologs from bacteria to humans that allow better understanding of the specific functions and physiological roles of the antiporters. Detailed information about the properties of multiple antiporters in individual strains is starting to explain how specific monovalent cation/proton antiporters play dominant roles in alkaline pH homeostasis in cells that have several additional antiporters catalyzing ostensibly similar reactions. New insights into the pH-dependent Na(+)/H(+) antiporter NhaA that plays an important role in Escherichia coli have recently emerged from the determination of the structure of NhaA. This review highlights the approaches, major findings and unresolved problems in alkaline pH homeostasis, focusing on the small number of well-characterized alkali-tolerant and extremely alkaliphilic bacteria.

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The Molecular Mechanism of Regulation of the NhaA Na ⁺ /H ⁺ Antiporter of Escherichia Coli , a key Transporter in the Adaptation to Na ⁺ and H ⁺

Cited by 13 publications

References 50 publications

ProP Is Required for the Survival of Desiccated Salmonella enterica Serovar Typhimurium Cells on a Stainless Steel Surface

ProP Is Required for the Survival of Desiccated Salmonella enterica Serovar Typhimurium Cells on a Stainless Steel Surface

Transcriptome Profiling of Shewanella oneidensis Gene Expression following Exposure to Acidic and Alkaline pH

Alkaline pH homeostasis in bacteria: New insights

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The Molecular Mechanism of Regulation of the NhaA Na + /H + Antiporter of Escherichia Coli , a key Transporter in the Adaptation to Na + and H +

Cited by 13 publications

References 50 publications

ProP Is Required for the Survival of Desiccated Salmonella enterica Serovar Typhimurium Cells on a Stainless Steel Surface

ProP Is Required for the Survival of Desiccated Salmonella enterica Serovar Typhimurium Cells on a Stainless Steel Surface

Transcriptome Profiling of Shewanella oneidensis Gene Expression following Exposure to Acidic and Alkaline pH

Alkaline pH homeostasis in bacteria: New insights

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The Molecular Mechanism of Regulation of the NhaA Na ⁺ /H ⁺ Antiporter of Escherichia Coli , a key Transporter in the Adaptation to Na ⁺ and H ⁺