scholarly journals Manipulation of the Anoxic Metabolism in Escherichia coli by ArcB Deletion Variants in the ArcBA Two-Component System

2012 ◽  
Vol 78 (24) ◽  
pp. 8784-8794 ◽  
Author(s):  
Gonzalo N. Bidart ◽  
Jimena A. Ruiz ◽  
Alejandra de Almeida ◽  
Beatriz S. Méndez ◽  
Pablo I. Nikel
Keyword(s):  
Escherichia Coli ◽  
Metabolic Flux ◽  
Expression Patterns ◽  
Phenotypic Traits ◽  
Wild Type ◽  
Two Component System ◽  
Component System ◽  
Content Type ◽  
Anoxic Conditions ◽  
Two Component

ABSTRACTBioprocesses conducted under conditions with restricted O2supply are increasingly exploited for the synthesis of reduced biochemicals using different biocatalysts. The model facultative anaerobeEscherichia colihas elaborate sensing and signal transduction mechanisms for redox control in response to the availability of O2and other electron acceptors. The ArcBA two-component system consists of ArcB, a membrane-associated sensor kinase, and ArcA, the cognate response regulator. The tripartite hybrid kinase ArcB possesses a transmembrane, a PAS, a primary transmitter (H1), a receiver (D1), and a phosphotransfer (H2) domain. Metabolic fluxes were compared under anoxic conditions in a wild-typeE. colistrain, its ΔarcBderivative, and two partialarcBdeletion mutants in which ArcB lacked either the H1 domain or the PAS-H1-D1 domains. These analyses revealed that elimination of different segments in ArcB determines a distinctive distribution ofd-glucose catabolic fluxes, different from that observed in the ΔarcBbackground. Metabolite profiles, enzyme activity levels, and gene expression patterns were also investigated in these strains. Relevant alterations were observed at the P-enol-pyruvate/pyruvate and acetyl coenzyme A metabolic nodes, and the formation of reduced fermentation metabolites, such as succinate,d-lactate, and ethanol, was favored in the mutant strains to different extents compared to the wild-type strain. These phenotypic traits were associated with altered levels of the enzymatic activities operating at these nodes, as well as with elevated NADH/NAD+ratios. Thus, targeted modification of global regulators to obtain different metabolic flux distributions under anoxic conditions is emerging as an attractive tool for metabolic engineering purposes.

scholarly journals Disruption of Glycolysis by Nutritional Immunity Activates a Two-Component System That Coordinates a Metabolic and Antihost Response by Staphylococcus aureus

mBio ◽  
2019 ◽  
Vol 10 (4) ◽  
Author(s):  
Paola K. Párraga Solórzano ◽  
Jiangwei Yao ◽  
Charles O. Rock ◽  
Thomas E. Kehl-Fie
Keyword(s):  
Staphylococcus Aureus ◽  
Metabolic Flux ◽  
Bacterial Species ◽  
Critical Role ◽  
Dependent Manner ◽  
Two Component System ◽  
Component System ◽  
Content Type ◽  
Nutritional Immunity ◽  
Two Component

ABSTRACT During infection, bacteria use two-component signal transduction systems to sense and adapt to the dynamic host environment. Despite critically contributing to infection, the activating signals of most of these regulators remain unknown. This also applies to the Staphylococcus aureus ArlRS two-component system, which contributes to virulence by coordinating the production of toxins, adhesins, and a metabolic response that enables the bacterium to overcome host-imposed manganese starvation. Restricting the availability of essential transition metals, a strategy known as nutritional immunity, constitutes a critical defense against infection. In this work, expression analysis revealed that manganese starvation imposed by the immune effector calprotectin or by the absence of glycolytic substrates activates ArlRS. Manganese starvation imposed by calprotectin also activated the ArlRS system even when glycolytic substrates were present. A combination of metabolomics, mutational analysis, and metabolic feeding experiments revealed that ArlRS is activated by alterations in metabolic flux occurring in the latter half of the glycolytic pathway. Moreover, calprotectin was found to induce expression of staphylococcal leukocidins in an ArlRS-dependent manner. These studies indicated that ArlRS is a metabolic sensor that allows S. aureus to integrate multiple environmental stresses that alter glycolytic flux to coordinate an antihost response and to adapt to manganese starvation. They also established that the latter half of glycolysis represents a checkpoint to monitor metabolic state in S. aureus. Altogether, these findings contribute to understanding how invading pathogens, such as S. aureus, adapt to the host during infection and suggest the existence of similar mechanisms in other bacterial species. IMPORTANCE Two-component regulatory systems enable bacteria to adapt to changes in their environment during infection by altering gene expression and coordinating antihost responses. Despite the critical role of two-component systems in bacterial survival and pathogenesis, the activating signals for most of these regulators remain unidentified. This is exemplified by ArlRS, a Staphylococcus aureus global regulator that contributes to virulence and to resisting host-mediated restriction of essential nutrients, such as manganese. In this report, we demonstrate that manganese starvation and the absence of glycolytic substrates activate ArlRS. Further investigations revealed that ArlRS is activated when the latter half of glycolysis is disrupted, suggesting that S. aureus monitors flux through the second half of this pathway. Host-imposed manganese starvation also induced the expression of pore-forming toxins in an ArlRS-dependent manner. Cumulatively, this work reveals that ArlRS acts as a sensor that links nutritional status, cellular metabolism, and virulence regulation.

scholarly journals Disruption of Phosphate Homeostasis Sensitizes Staphylococcus aureus to Nutritional Immunity

2020 ◽  
Vol 88 (6) ◽  
Author(s):  
Jessica L. Kelliher ◽  
Erin B. Brazel ◽  
Jana N. Radin ◽  
Eliot S. Joya ◽  
Paola K. Párraga Solórzano ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Defined Medium ◽  
Wild Type ◽  
Two Component System ◽  
Phosphate Homeostasis ◽  
Component System ◽  
Content Type ◽  
Nutritional Immunity ◽  
Two Component ◽  
Overexpressing Strain

ABSTRACT To control infection, mammals actively withhold essential nutrients, including the transition metal manganese, by a process termed nutritional immunity. A critical component of this host response is the manganese-chelating protein calprotectin. While many bacterial mechanisms for overcoming nutritional immunity have been identified, the intersection between metal starvation and other essential inorganic nutrients has not been investigated. Here, we report that overexpression of an operon encoding a highly conserved inorganic phosphate importer, PstSCAB, increases the sensitivity of Staphylococcus aureus to calprotectin-mediated manganese sequestration. Further analysis revealed that overexpression of pstSCAB does not disrupt manganese acquisition or result in overaccumulation of phosphate by S. aureus. However, it does reduce the ability of S. aureus to grow in phosphate-replete defined medium. Overexpression of pstSCAB does not aberrantly activate the phosphate-responsive two-component system PhoPR, nor was this two-component system required for sensitivity to manganese starvation. In a mouse model of systemic staphylococcal disease, a pstSCAB-overexpressing strain is significantly attenuated compared to wild-type S. aureus. This defect is partially reversed in a calprotectin-deficient mouse, in which manganese is more readily available. Given that expression of pstSCAB is regulated by PhoPR, these findings suggest that overactivation of PhoPR would diminish the ability of S. aureus to resist nutritional immunity and cause infection. As PhoPR is also necessary for bacterial virulence, these findings imply that phosphate homeostasis represents a critical regulatory node whose activity must be precisely controlled in order for S. aureus and other pathogens to cause infection.

scholarly journals The Escherichia coli BarA-UvrY Two-Component System Is Needed for Efficient Switching between Glycolytic and Gluconeogenic Carbon Sources

2003 ◽  
Vol 185 (3) ◽  
pp. 843-853 ◽  
Author(s):  
Anna-Karin Pernestig ◽  
Dimitris Georgellis ◽  
Tony Romeo ◽  
Kazushi Suzuki ◽  
Henrik Tomenius ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Response Regulator ◽  
Carbon Sources ◽  
Regulation System ◽  
Wild Type ◽  
Two Component System ◽  
Kinase Gene ◽  
Component System ◽  
E Coli ◽  
Two Component

ABSTRACT The Escherichia coli BarA and UvrY proteins were recently demonstrated to constitute a novel two-component system, although its function has remained largely elusive. Here we show that mutations in the sensor kinase gene, barA, or the response regulator gene, uvrY, in uropathogenic E. coli drastically affect survival in long-term competition cultures. Using media with gluconeogenic carbon sources, the mutants have a clear growth advantage when competing with the wild type, but using media with carbon sources feeding into the glycolysis leads to a clear growth advantage for the wild type. Results from competitions with mutants in the carbon storage regulation system, CsrA/B, known to be a master switch between glycolysis and gluconeogenesis, led us to propose that the BarA-UvrY two-component system controls the Csr system. Taking these results together, we propose the BarA-UvrY two-component system is crucial for efficient adaptation between different metabolic pathways, an essential function for adaptation to a new environment.

scholarly journals The Cold-Induced Two-Component System CBO0366/CBO0365 Regulates Metabolic Pathways with Novel Roles in Group I Clostridium botulinum ATCC 3502 Cold Tolerance

2013 ◽  
Vol 80 (1) ◽  
pp. 306-319 ◽  
Author(s):  
Elias Dahlsten ◽  
Zhen Zhang ◽  
Panu Somervuo ◽  
Nigel P. Minton ◽  
Miia Lindström ◽  
...  
Keyword(s):  
Cold Tolerance ◽  
Clostridium Botulinum ◽  
Phosphate Uptake ◽  
Expression Patterns ◽  
Abe Fermentation ◽  
Two Component System ◽  
Component System ◽  
Content Type ◽  
Group I ◽  
Two Component

ABSTRACTThe two-component system CBO0366/CBO0365 was recently demonstrated to have a role in cold tolerance of group IClostridium botulinumATCC 3502. The mechanisms under its control, ultimately resulting in increased sensitivity to low temperature, are unknown. A transcriptomic analysis with DNA microarrays was performed to identify the differences in global gene expression patterns of the wild-type ATCC 3502 and a derivative mutant with insertionally inactivatedcbo0365at 37 and 15°C. Altogether, 150 or 141 chromosomal coding sequences (CDSs) were found to be differently expressed in thecbo0365mutant at 37 or 15°C, respectively, and thus considered to be under the direct or indirect transcriptional control of the response regulator CBO0365. Of the differentially expressed CDSs, expression of 141 CDSs was similarly affected at both temperatures investigated, suggesting that the putative CBO0365 regulon was practically not affected by temperature. The regulon involved genes related to acetone-butanol-ethanol (ABE) fermentation, motility, arsenic resistance, and phosphate uptake and transport. Deteriorated growth at 17°C was observed for mutants with disrupted ABE fermentation pathway components (crt,bcd,bdh, andctfA), arsenic detoxifying machinery components (arsCandarsR), or phosphate uptake mechanism components (phoT), suggesting roles for these mechanisms in cold tolerance of group IC. botulinum. Electrophoretic mobility shift assays showed recombinant CBO0365 to bind to the promoter regions ofcrt,arsR, andphoT, as well as to the promoter region of its own operon, suggesting direct DNA-binding transcriptional activation or repression as a means for CBO0365 in regulating these operons. The results provide insight to the mechanisms group IC. botulinumutilizes in coping with cold.

scholarly journals Mutational Activation of the AmgRS Two-Component System in Aminoglycoside-Resistant Pseudomonas aeruginosa

2013 ◽  
Vol 57 (5) ◽  
pp. 2243-2251 ◽  
Author(s):  
Calvin Ho-Fung Lau ◽  
Sebastien Fraud ◽  
Marcus Jones ◽  
Scott N. Peterson ◽  
Keith Poole
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Fold Increase ◽  
Wild Type ◽  
Two Component System ◽  
Aminoglycoside Resistance ◽  
Gain Of Function ◽  
Component System ◽  
Content Type ◽  
Resistance Phenotype ◽  
Two Component

ABSTRACTTheamgRSoperon encodes a presumed membrane stress-responsive two-component system linked to intrinsic aminoglycoside resistance inPseudomonas aeruginosa. Genome sequencing of a lab isolate showing modest pan-aminoglycoside resistance, strain K2979, revealed a number of mutations, including a substitution inamgSthat produced an R182C change in the AmgS sensor kinase product of this gene. Introduction of this mutation into an otherwise wild-type strain recapitulated the resistance phenotype, while correcting the mutation in the resistant mutant abrogated the resistant phenotype, confirming that theamgSmutation is responsible for the aminoglycoside resistance of strain K2979. TheamgSR182mutation promoted an AmgR-dependent, 2- to 3-fold increase in expression of the AmgRS target geneshtpXand PA5528, mirroring the impact of aminoglycoside exposure of wild-type cells onhtpXand PA5528 expression. This suggests thatamgSR182is a gain-of-function mutation that activates AmgS and the AmgRS two-component system in promoting modest resistance to aminoglycosides. Screening of several pan-aminoglycoside-resistant clinical isolates ofP. aeruginosarevealed three that showed elevatedhtpXand PA5528 expression and harbored single amino acid-altering mutations inamgS(V121G or D106N) and no mutations inamgR. Introduction of theamgSV121Gmutation into wild-typeP. aeruginosagenerated a resistance phenotype reminiscent of theamgSR182mutant and produced a 2- to 3-fold increase inhtpXand PA5528 expression, confirming that it, too, is a gain-of-function aminoglycoside resistance-promoting mutation. These results highlight the contribution ofamgSmutations and activation of the AmgRS two-component system to acquired aminoglycoside resistance in lab and clinical isolates ofP. aeruginosa.

scholarly journals The BarA-UvrY Two-Component System Regulates Virulence in Avian Pathogenic Escherichia coli O78:K80:H9

2006 ◽  
Vol 74 (8) ◽  
pp. 4900-4909 ◽  
Author(s):  
Christopher D. Herren ◽  
Arindam Mitra ◽  
Senthil Kumar Palaniyandi ◽  
Adam Coleman ◽  
Subbiah Elankumaran ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Chicken Embryo ◽  
Phenotypic Traits ◽  
Virulence Determinants ◽  
Two Component System ◽  
Component System ◽  
Two Component ◽  
Embryo Lethality

ABSTRACT The BarA-UvrY two-component system (TCS) in Escherichia coli is known to regulate a number of phenotypic traits. Both in vitro and in vivo assays, including the chicken embryo lethality assay, showed that this TCS regulates virulence in avian pathogenic E. coli (APEC) serotype O78:K80:H9. A number of virulence determinants, such as the abilities to adhere, invade, persist within tissues, survive within macrophages, and resist bactericidal effects of serum complement, were compromised in mutants lacking either the barA or uvrY gene. The reduced virulence was attributed to down regulation of type 1 and Pap fimbriae, reduced exopolysaccharide production, and increased susceptibility to oxidative stress. Our results indicate that BarA-UvrY regulates virulence properties in APEC and that the chicken embryo lethality assay can be used as a surrogate model to determine virulence determinants and their regulation in APEC strains.

scholarly journals Nutritional Regulation of the Sae Two-Component System by CodY inStaphylococcus aureus

2018 ◽  
Vol 200 (8) ◽  
Author(s):  
Kevin D. Mlynek ◽  
William E. Sause ◽  
Derek E. Moormeier ◽  
Marat R. Sadykov ◽  
Kurt R. Hill ◽  
...  
Keyword(s):  
Gene Expression ◽  
Virulence Factors ◽  
Virulence Gene ◽  
Nutrient Depletion ◽  
Global Regulator ◽  
Two Component System ◽  
Component System ◽  
Content Type ◽  
Virulence Gene Expression ◽  
Two Component

ABSTRACTStaphylococcus aureussubverts innate defenses during infection in part by killing host immune cells to exacerbate disease. This human pathogen intercepts host cues and activates a transcriptional response via theS. aureusexoprotein expression (SaeR/SaeS [SaeR/S]) two-component system to secrete virulence factors critical for pathogenesis. We recently showed that the transcriptional repressor CodY adjusts nuclease (nuc) gene expression via SaeR/S, but the mechanism remained unknown. Here, we identified two CodY binding motifs upstream of thesaeP1 promoter, which suggested direct regulation by this global regulator. We show that CodY shares a binding site with the positive activator SaeR and that alleviating direct CodY repression at this site is sufficient to abrogate stochastic expression, suggesting that CodY repressessaeexpression by blocking SaeR binding. Epistasis experiments support a model that CodY also controlssaeindirectly through Agr and Rot-mediated repression of thesaeP1 promoter. We also demonstrate that CodY repression ofsaerestrains production of secreted cytotoxins that kill human neutrophils. We conclude that CodY plays a previously unrecognized role in controlling virulence gene expression via SaeR/S and suggest a mechanism by which CodY acts as a master regulator of pathogenesis by tying nutrient availability to virulence gene expression.IMPORTANCEBacterial mechanisms that mediate the switch from a commensal to pathogenic lifestyle are among the biggest unanswered questions in infectious disease research. Since the expression of most virulence genes is often correlated with nutrient depletion, this implies that virulence is a response to the lack of nourishment in host tissues and that pathogens likeS. aureusproduce virulence factors in order to gain access to nutrients in the host. Here, we show that specific nutrient depletion signals appear to be funneled to the SaeR/S system through the global regulator CodY. Our findings reveal a strategy by whichS. aureusdelays the production of immune evasion and immune-cell-killing proteins until key nutrients are depleted.

scholarly journals The Staphylococcus aureus KdpDE Two-Component System Couples Extracellular K+Sensing and Agr Signaling to Infection Programming

2011 ◽  
Vol 79 (6) ◽  
pp. 2154-2167 ◽  
Author(s):  
Ting Xue ◽  
Yibo You ◽  
De Hong ◽  
Haipeng Sun ◽  
Baolin Sun
Keyword(s):  
Staphylococcus Aureus ◽  
Uptake System ◽  
Main Function ◽  
Two Component System ◽  
Component System ◽  
Content Type ◽  
Two Component ◽  
Virulence Regulator ◽  
External K

ABSTRACTThe Kdp system is widely distributed among bacteria. InEscherichia coli, the Kdp-ATPase is a high-affinity K+uptake system and its expression is activated by the KdpDE two-component system in response to K+limitation or salt stress. However, information about the role of this system in many bacteria still remains obscure. Here we demonstrate that KdpFABC inStaphylococcus aureusis not a major K+transporter and that the main function of KdpDE is not associated with K+transport but that instead it regulates transcription for a series of virulence factors through sensing external K+concentrations, indicating that this bacterium might modulate its infectious status through sensing specific external K+stimuli in different environments. Our results further reveal thatS. aureusKdpDE is upregulated by the Agr/RNAIII system, which suggests that KdpDE may be an important virulence regulator coordinating the external K+sensing and Agr signaling during pathogenesis in this bacterium.

scholarly journals The CasKR Two-Component System Is Required for the Growth of Mesophilic and Psychrotolerant Bacillus cereus Strains at Low Temperatures

2014 ◽  
Vol 80 (8) ◽  
pp. 2493-2503 ◽  
Author(s):  
Sara Esther Diomandé ◽  
Stéphanie Chamot ◽  
Vera Antolinos ◽  
Florian Vasai ◽  
Marie-Hélène Guinebretière ◽  
...  
Keyword(s):  
Bacillus Cereus ◽  
Food Poisoning ◽  
Two Component System ◽  
Diverse Range ◽  
Component System ◽  
Content Type ◽  
Two Component ◽  
Temperature Ranges ◽  
Different Strains

ABSTRACTThe different strains ofBacillus cereuscan grow at temperatures covering a very diverse range. SomeB. cereusstrains can grow in chilled food and consequently cause food poisoning. We have identified a new sensor/regulator mechanism involved in low-temperatureB. cereusgrowth. Construction of a mutant of this two-component system enabled us to show that this system, called CasKR, is required for growth at the minimal temperature (Tmin). CasKR was also involved in optimal cold growth aboveTminand in cell survival belowTmin. Microscopic observation showed that CasKR plays a key role in cell shape during cold growth. Introducing thecasKRgenes in a ΔcasKRmutant restored its ability to grow atTmin. Although it was first identified in the ATCC 14579 model strain, this mechanism has been conserved in most strains of theB. cereusgroup. We show that the role of CasKR in cold growth is similar in otherB. cereus sensu latostrains with different growth temperature ranges, including psychrotolerant strains.

scholarly journals Identification of a Second Two-Component Signal Transduction System That Controls Fosfomycin Tolerance and Glycerol-3-Phosphate Uptake

2014 ◽  
Vol 197 (5) ◽  
pp. 861-871 ◽  
Author(s):  
Kumiko Kurabayashi ◽  
Yuko Hirakawa ◽  
Koichi Tanimoto ◽  
Haruyoshi Tomita ◽  
Hidetada Hirakawa
Keyword(s):  
Phosphate Uptake ◽  
Response Regulator ◽  
Anaerobic Respiration ◽  
Regulatory System ◽  
Carbon Substrate ◽  
Two Component System ◽  
Component System ◽  
Content Type ◽  
Two Component ◽  
Biological Cost

Particular interest in fosfomycin has resurfaced because it is a highly beneficial antibiotic for the treatment of refractory infectious diseases caused by pathogens that are resistant to other commonly used antibiotics. The biological cost to cells of resistance to fosfomycin because of chromosomal mutation is high. We previously found that a bacterial two-component system, CpxAR, induces fosfomycin tolerance in enterohemorrhagicEscherichia coli(EHEC) O157:H7. This mechanism does not rely on irreversible genetic modification and allows EHEC to relieve the fitness burden that results from fosfomycin resistance in the absence of fosfomycin. Here we show that another two-component system, TorSRT, which was originally characterized as a regulatory system for anaerobic respiration utilizing trimethylamine-N-oxide (TMAO), also induces fosfomycin tolerance. Activation of the Tor regulatory pathway by overexpression oftorR, which encodes the response regulator, or addition of TMAO increased fosfomycin tolerance in EHEC. We also show that phosphorylated TorR directly represses the expression ofglpT, a gene that encodes a symporter of fosfomycin and glycerol-3-phosphate, and activation of the TorR protein results in the reduced uptake of fosfomycin by cells. However, cells in which the Tor pathway was activated had an impaired growth phenotype when cultured with glycerol-3-phosphate as a carbon substrate. These observations suggest that the TorSRT pathway is the second two-component system to reversibly control fosfomycin tolerance and glycerol-3-phosphate uptake in EHEC, and this may be beneficial for bacteria by alleviating the biological cost. We expect that this mechanism could be a potential target to enhance the utility of fosfomycin as chemotherapy against multidrug-resistant pathogens.

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