scholarly journals Regulation of tartrate metabolism by TtdR and relation to the DcuS–DcuR-regulated C4-dicarboxylate metabolism of Escherichia coli

Microbiology ◽  
2009 ◽  
Vol 155 (11) ◽  
pp. 3632-3640 ◽  
Author(s):  
Ok Bin Kim ◽  
Julia Reimann ◽  
Hanna Lukas ◽  
Uwe Schumacher ◽  
Jan Grimpo ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Promoter Region ◽  
Anaerobic Conditions ◽  
Two Component System ◽  
Two Component ◽  
Fumarate Respiration ◽  
Mutual Regulation ◽  
Genes Encoding ◽  
Type Gene ◽  
Tartrate Dehydratase

Escherichia coli catabolizes l-tartrate under anaerobic conditions to oxaloacetate by the use of l-tartrate/succinate antiporter TtdT and l-tartrate dehydratase TtdAB. Subsequently, l-malate is channelled into fumarate respiration and degraded to succinate by the use of fumarase FumB and fumarate reductase FrdABCD. The genes encoding the latter pathway (dcuB, fumB and frdABCD) are transcriptionally activated by the DcuS–DcuR two-component system. Expression of the l-tartrate-specific ttdABT operon encoding TtdAB and TtdT was stimulated by the LysR-type gene regulator TtdR in the presence of l- and meso-tartrate, and repressed by O2 and nitrate. Anaerobic expression required a functional fnr gene, and nitrate repression depended on NarL and NarP. Expression of ttdR, encoding TtdR, was repressed by O2, nitrate and glucose, and positively regulated by TtdR and DcuS. Purified TtdR specifically bound to the ttdR–ttdA promoter region. TtdR was also required for full expression of the DcuS–DcuR-dependent dcuB gene in the presence of tartrate. Overall, expression of the ttdABT genes is subject to l-/meso-tartrate-dependent induction, and to aerobic and nitrate repression. The control is exerted directly at ttdA and in addition indirectly by regulating TtdR levels. TtdR recognizes a subgroup (l- and meso-tartrate) of the stimuli perceived by the sensor DcuS, which responds to all C4-dicarboxylates; both systems apparently communicate by mutual regulation of the regulatory genes.

scholarly journals The l-Tartrate/Succinate Antiporter TtdT (YgjE) of l-Tartrate Fermentation in Escherichia coli

2006 ◽  
Vol 189 (5) ◽  
pp. 1597-1603 ◽  
Author(s):  
Ok Bin Kim ◽  
Gottfried Unden
Keyword(s):  
Escherichia Coli ◽  
Electron Donor ◽  
Reverse Transcription ◽  
Anaerobic Growth ◽  
Anaerobic Conditions ◽  
Reverse Transcription Pcr ◽  
Citrate Fermentation ◽  
Genes Encoding ◽  
And Function ◽  
Tartrate Dehydratase

ABSTRACT Escherichia coli ferments l-tartrate under anaerobic conditions in the presence of an additional electron donor to succinate. The carrier for l-tartrate uptake and succinate export and its relation to the general C4-dicarboxylate carriers DcuA, DcuB, and DcuC were studied. The secondary carrier TtdT, encoded by the ttdT (previously called ygjE) gene, is required for the uptake of l-tartrate. The ttdT gene is located downstream of the ttdA and ttdB genes, encoding the l-tartrate dehydratase TtdAB. Analysis of mRNA by reverse transcription-PCR showed that ttdA, ttdB, and ttdT are cotranscribed. Deletion of ttdT abolished growth by l-tartrate and degradation of l-tartrate completely. Bacteria containing TtdT catalyze l-tartrate or succinate uptake and specific heterologous l-tartrate/succinate antiporting. d-Tartrate is not a substrate for TtdT. TtdT operates preferentially in the direction of tartrate uptake and succinate excretion. The Dcu carriers do not support anaerobic growth on l-tartrate or l-tartrate transport. TtdT is related in sequence and function to CitT, which catalyzes heterologous citrate/succinate antiporting in citrate fermentation.

scholarly journals Bile Salts Differentially Enhance Resistance of Enterohemorrhagic Escherichia Coli O157:H7 to Human Cationic Antimicrobial Peptides

2021 ◽  
Author(s):  
Crystal Gadishaw-Lue
Keyword(s):  
Escherichia Coli ◽  
Lipid A ◽  
Enterohemorrhagic Escherichia Coli ◽  
Escherichia Coli O157 ◽  
Salt Mixture ◽  
Two Component System ◽  
Two Component ◽  
Genes Encoding ◽  
Uremic Syndrome ◽  
Bacterial Outer Membrane

Enterohemorrhagic Escherichia coli (EHEC) causes severe food and water-borne illness associated with diarrhea, hemorrhagic colitis (HC), and hemolytic-uremic syndrome (HUS). Previously, we reported that treatment of EHEC with a physiologically relevant bile salt mixture (BSM) upregulates genes encoding a two-component system (TCS) (basRS) and a lipid A modification pathway (arnBCADTEF). The current study examines the effect of BSM treatment on EHEC resistance to human cationic antimicrobials, human defensin, HD-5 and cathelicidin, LL-37. Results show a significant increase in resistance to HD-5 when EHEC are pre-treated with BSM as compared to untreated EHEC. The BS-induced resistance phenotype is lost in each of the arnT and basS mutants. Interestingly, BSM treatment does not affect resistance to LL-37. The results of this study provide evidence that BS serve as an environmental cue by triggering changes via a TCS that result in protective modifications of the bacterial outer membrane, thereby increasing resistance to HD-5.

scholarly journals Bile salts differentially enhance resistance of enterohemorrhagic escherichia coli 0157:H7 to human cationic antimicrobial peptides

2021 ◽  
Author(s):  
Crystal Gadishaw-Lue
Keyword(s):  
Escherichia Coli ◽  
Bile Salts ◽  
Lipid A ◽  
Enterohemorrhagic Escherichia Coli ◽  
Salt Mixture ◽  
Two Component System ◽  
Two Component ◽  
Genes Encoding ◽  
Uremic Syndrome ◽  
Bacterial Outer Membrane

Enterohemorrhagic Escherichia coli (EHEC) causes severe food and water-borne illness associated with diarrhea, hemorrhagic colitis (HC), and hemolytic-uremic syndrome (HUS). Previously, we reported that treatment of EHEC with a physiologically relevant bile salt mixture (BSM) upregulates genes encoding a two-component system (TCS) (basRS) and a lipid A modification pathway (arnBCADTEF). The current study examines the effect of BSM treatment on EHEC resistance to human cationic antimicrobials, human defensin, HD-5 and cathelicidin, LL-37. Results show a significant increase in resistance to HD-5 when EHEC are pre-treated with BSM as compared to untreated EHEC. The BS-induced resistance phenotype is lost in each of the arnT and basS mutants. Interestingly, BSM treatment does not affect resistance to LL-37. The results of this study provide evidence that BS serve as an environmental cue by triggering changes via a TCS that result in protective modifications of the bacterial outer membrane, thereby increasing resistance to HD-5.

scholarly journals Bile Salts Differentially Enhance Resistance of Enterohemorrhagic Escherichia Coli O157:H7 to Human Cationic Antimicrobial Peptides

2021 ◽  
Author(s):  
Crystal Gadishaw-Lue
Keyword(s):  
Escherichia Coli ◽  
Lipid A ◽  
Enterohemorrhagic Escherichia Coli ◽  
Escherichia Coli O157 ◽  
Salt Mixture ◽  
Two Component System ◽  
Two Component ◽  
Genes Encoding ◽  
Uremic Syndrome ◽  
Bacterial Outer Membrane

Enterohemorrhagic Escherichia coli (EHEC) causes severe food and water-borne illness associated with diarrhea, hemorrhagic colitis (HC), and hemolytic-uremic syndrome (HUS). Previously, we reported that treatment of EHEC with a physiologically relevant bile salt mixture (BSM) upregulates genes encoding a two-component system (TCS) (basRS) and a lipid A modification pathway (arnBCADTEF). The current study examines the effect of BSM treatment on EHEC resistance to human cationic antimicrobials, human defensin, HD-5 and cathelicidin, LL-37. Results show a significant increase in resistance to HD-5 when EHEC are pre-treated with BSM as compared to untreated EHEC. The BS-induced resistance phenotype is lost in each of the arnT and basS mutants. Interestingly, BSM treatment does not affect resistance to LL-37. The results of this study provide evidence that BS serve as an environmental cue by triggering changes via a TCS that result in protective modifications of the bacterial outer membrane, thereby increasing resistance to HD-5.

scholarly journals Bile salts differentially enhance resistance of enterohemorrhagic escherichia coli 0157:H7 to human cationic antimicrobial peptides

2021 ◽  
Author(s):  
Crystal Gadishaw-Lue
Keyword(s):  
Escherichia Coli ◽  
Bile Salts ◽  
Lipid A ◽  
Enterohemorrhagic Escherichia Coli ◽  
Salt Mixture ◽  
Two Component System ◽  
Two Component ◽  
Genes Encoding ◽  
Uremic Syndrome ◽  
Bacterial Outer Membrane

Enterohemorrhagic Escherichia coli (EHEC) causes severe food and water-borne illness associated with diarrhea, hemorrhagic colitis (HC), and hemolytic-uremic syndrome (HUS). Previously, we reported that treatment of EHEC with a physiologically relevant bile salt mixture (BSM) upregulates genes encoding a two-component system (TCS) (basRS) and a lipid A modification pathway (arnBCADTEF). The current study examines the effect of BSM treatment on EHEC resistance to human cationic antimicrobials, human defensin, HD-5 and cathelicidin, LL-37. Results show a significant increase in resistance to HD-5 when EHEC are pre-treated with BSM as compared to untreated EHEC. The BS-induced resistance phenotype is lost in each of the arnT and basS mutants. Interestingly, BSM treatment does not affect resistance to LL-37. The results of this study provide evidence that BS serve as an environmental cue by triggering changes via a TCS that result in protective modifications of the bacterial outer membrane, thereby increasing resistance to HD-5.

scholarly journals Intra- and Interspecies Signaling betweenStreptococcus salivarius and Streptococcus pyogenes Mediated by SalA and SalA1 Lantibiotic Peptides

2001 ◽  
Vol 183 (13) ◽  
pp. 3931-3938 ◽  
Author(s):  
M. Upton ◽  
J. R. Tagg ◽  
P. Wescombe ◽  
H. F. Jenkinson
Keyword(s):  
Streptococcus Pyogenes ◽  
Response Regulator ◽  
Genetic Locus ◽  
Two Component System ◽  
Peptide Modification ◽  
Insertional Inactivation ◽  
Two Component ◽  
Genes Encoding ◽  
Dose Dependent

ABSTRACT Streptococcus salivarius 20P3 produces a 22-amino-acid residue lantibiotic, designated salivaricin A (SalA), that inhibits the growth of a range of streptococci, including all strains ofStreptococcus pyogenes. Lantibiotic production is associated with the sal genetic locus comprisingsalA, the lantibiotic structural gene; salBCTXgenes encoding peptide modification and export machinery proteins; andsalYKR genes encoding a putative immunity protein and two-component sensor-regulator system. Insertional inactivation ofsalB in S. salivarius 20P3 resulted in abrogation of SalA peptide production, of immunity to SalA, and ofsalA transcription. Addition of exogenous SalA peptide tosalB mutant cultures induced dose-dependent expression ofsalA mRNA (0.2 kb), demonstrating that SalA production was normally autoregulated. Inactivation of salR encoding the response regulator of the SalKR two-component system led to reduced production of, and immunity to, SalA. The sal genetic locus was also present in S. pyogenes SF370 (M type 1), but because of a deletion across the salBCT genes, the corresponding lantibiotic peptide, designated SalA1, was not produced. However, in S. pyogenes T11 (M type 4) the sallocus gene complement was apparently complete, and active SalA1 peptide was synthesized. Exogenously added SalA1 peptide from S. pyogenes T11 induced salA1 transcription in S. pyogenes SF370 and in an isogenic S. pyogenes T11salB mutant and salA transcription in S. salivarius 20P3 salB. Thus, SalA and SalA1 are examples of streptococcal lantibiotics whose production is autoregulated. These peptides act as intra- and interspecies signaling molecules, modulating lantibiotic production and possibly influencing streptococcal population ecology in the oral cavity.

HprSR is a Reactive Chlorine Species-Sensing, Two-Component System in Escherichia coli

2021 ◽  
Author(s):  
Sara El Hajj ◽  
Camille Henry ◽  
Camille Andrieu ◽  
Alexandra Vergnes ◽  
Laurent Loiseau ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Hypochlorous Acid ◽  
Methionine Sulfoxide ◽  
Methionine Sulfoxide Reductase ◽  
Repair System ◽  
Bacterial Cells ◽  
Two Component System ◽  
Component System ◽  
Two Component ◽  
Redox Switch

Two-component systems (TCS) are signalling pathways that allow bacterial cells to sense, respond and adapt to fluctuating environments. Among the classical TCS of Escherichia coli , HprSR has recently been shown to be involved in the regulation of msrPQ , which encodes the periplasmic methionine sulfoxide reductase system. In this study, we demonstrate that hypochlorous acid (HOCl) induces the expression of msrPQ in an HprSR-dependant manner, whereas H 2 O 2 , NO and paraquat (a superoxide generator) do not. Therefore, HprS appears to be an HOCl-sensing histidine kinase. Using a directed mutagenesis approach, we show that Met residues located in the periplasmic loop of HprS are important for its activity: as HOCl preferentially oxidizes Met residues, we provide evidence that HprS could be activated via the reversible oxidation of its methionine residues, meaning that MsrPQ plays a role in switching HprSR off. We propose that the activation of HprS by HOCl could occur through a Met redox switch. HprSR appears to be the first characterized TCS able to detect reactive chlorine species (RCS) in E. coli . This study represents an important step towards understanding the mechanisms of RCS resistance in prokaryotes. IMPORTANCE Understanding how bacteria respond to oxidative stress at the molecular level is crucial in the fight against pathogens. HOCl is one of the most potent industrial and physiological microbiocidal oxidants. Therefore bacteria have developed counterstrategies to survive HOCl-induced stress. Over the last decade, important insights into these bacterial protection factors have been obtained. Our work establishes HprSR as a reactive chlorine species-sensing, two-component system in Escherichia coli MG1655, which regulates the expression of MsrPQ, a repair system for HOCl-oxidized proteins. Moreover we provide evidence suggesting that HOCl could activate HprS through a methionine redox switch.

Involvement of AtoSC two-component system in Escherichia coli flagellar regulon

Amino Acids ◽  
2011 ◽  
Vol 43 (2) ◽  
pp. 833-844 ◽  
Author(s):  
Marina C. Theodorou ◽  
Evaggelos C. Theodorou ◽  
Dimitrios A. Kyriakidis
Keyword(s):  
Escherichia Coli ◽  
Two Component System ◽  
Component System ◽  
Two Component ◽  
Flagellar Regulon

scholarly journals Polar Localization of a Tripartite Complex of the Two-Component System DcuS/DcuR and the Transporter DctA in Escherichia coli Depends on the Sensor Kinase DcuS

PLoS ONE ◽  
2014 ◽  
Vol 9 (12) ◽  
pp. e115534 ◽  
Author(s):  
Patrick D. Scheu ◽  
Philipp A. Steinmetz ◽  
Felix Dempwolff ◽  
Peter L. Graumann ◽  
Gottfried Unden
Keyword(s):  
Escherichia Coli ◽  
Sensor Kinase ◽  
Two Component System ◽  
Component System ◽  
Polar Localization ◽  
Two Component
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