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1

Xie, Mingquan, Mengyuan Wu y Aidong Han. "Structural insights into the signal transduction mechanism of the K+-sensing two-component system KdpDE". Science Signaling 13, n.º 643 (4 de agosto de 2020): eaaz2970. http://dx.doi.org/10.1126/scisignal.aaz2970.

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Two-component systems (TCSs), which consist of a histidine kinase (HK) sensor and a response regulator (RR), are important for bacteria to quickly sense and respond to various environmental signals. HKs and RRs typically function as a cognate pair, interacting only with one another to transduce signaling. Precise signal transduction in a TCS depends on the specific interactions between the receiver domain (RD) of the RR and the dimerization and histidine phosphorylation domain (DHp) of the HK. Here, we determined the complex structure of KdpDE, a TCS consisting of the HK KdpD and the RR KdpE, which is responsible for K+ homeostasis. Both the RD and the DNA binding domain (DBD) of KdpE interacted with KdpD. Although the RD of KdpE and the DHp of KdpD contributed to binding specificity, the DBD mediated a distinct interaction with the catalytic ATP-binding (CA) domain of KdpD that was indispensable for KdpDE-mediated signal transduction. Moreover, the DBD-CA interface largely overlapped with that of the DBD-DNA complex, leading to competition between KdpD and its target promoter in a KdpE phosphorylation–dependent manner. In addition, the extended C-terminal tail of the CA domain was critical for stabilizing the interaction with KdpDE and for signal transduction. Together, these data provide a molecular basis for specific KdpD and KdpE interactions that play key roles in efficient signal transduction and transcriptional regulation by this TCS.
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2

Sardesai, Abhijit A. y J. Gowrishankar. "trans-Acting Mutations in Loci Other than kdpDE That Affect kdp Operon Regulation inEscherichia coli: Effects of Cytoplasmic Thiol Oxidation Status and Nucleoid Protein H-NS on kdpExpression". Journal of Bacteriology 183, n.º 1 (1 de enero de 2001): 86–93. http://dx.doi.org/10.1128/jb.183.1.86-93.2001.

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ABSTRACT Transcription of the K+ transport operonkdp in Escherichia coli is induced during K+-limited growth by the action of a dual-component phosphorelay regulatory system comprised of a sensor kinase (integral membrane protein), KdpD, and a DNA-binding response regulator (cytoplasmic protein), KdpE. In this study, we screened for newdke (named dke for decreased kdpexpression) mutations (in loci other than kdpDE) that led to substantially decreased kdp expression. Onedke mutation was shown to be in hns, encoding the nucleoid protein H-NS. Another dke mutation was mapped to trxB (encoding thioredoxin reductase), and an equivalent reduction in kdp expression was demonstrated also fortrxA mutants that are deficient in thioredoxin 1. Exogenously provided dithiothreitol rescued the kdpexpression defect in trxB but not trxA mutants. Neither trxB nor trxA affected gene regulation mediated by another dual-component system tested, EnvZ-OmpR. Mutations in genes dsbC and dsbD did not affectkdp expression, suggesting that the trx effects on kdp are not mediated by alterations in protein disulfide bond status in the periplasm. Reduced kdp expression was observed even in a trxB strain that harbored a variant KdpD polypeptide bearing no Cys residues. A trxB hns double mutant was even more severely affected for kdp expression than either single mutant. The dke mutations themselves had no effect on strength of the signal controlling kdpexpression, and constitutive mutations in kdpDE were epistatic to hns and trxB. These results indicate that perturbations in cytoplasmic thiol oxidation status and in levels of the H-NS protein exert additive effects, direct or indirect, at a step(s) upstream of KdpD in the signal transduction pathway, which significantly influence the magnitude of KdpD kinase activity obtained for a given strength of the inducing signal forkdp transcription.
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3

Ballal, Anand, Marc Bramkamp, Hema Rajaram, Petra Zimmann, Shree Kumar Apte y Karlheinz Altendorf. "An Atypical KdpD Homologue from the Cyanobacterium Anabaena sp. Strain L-31: Cloning, In Vivo Expression, and Interaction with Escherichia coli KdpD-CTD". Journal of Bacteriology 187, n.º 14 (julio de 2005): 4921–27. http://dx.doi.org/10.1128/jb.187.14.4921-4927.2005.

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ABSTRACT The kdpFABC operon of Escherichia coli, coding for the high-affinity K+ transport system KdpFABC, is transcriptionally regulated by the products of the adjacently located kdpDE genes. The KdpD protein is a membrane-bound sensor kinase consisting of a large N-terminal domain and a C-terminal transmitter domain interconnected by four transmembrane segments (the transmembrane segments together with the C-terminal transmitter domain of KdpD are referred to as CTD), while KdpE is a cytosolic response regulator. We have cloned and sequenced the kdp operon from a nitrogen-fixing, filamentous cyanobacterium, Anabaena sp. strain L-31 (GenBank accession. number AF213466 ). The kdpABC genes are similar in size to those of E. coli, but the kdpD gene is short (coding only for 365 amino acids), showing homology only to the N-terminal domain of E. coli KdpD. A kdpE-like gene is absent in the vicinity of this operon. Anabaena KdpD with six C-terminal histidines was overproduced in E. coli and purified by Ni2+-nitrilotriacetic acid affinity chromatography. With antisera raised against the purified Anabaena KdpD, the protein was detected in Anabaena sp. strain L-31 membranes. The membrane-associated or soluble form of the Anabaena KdpD(6His) could be photoaffinity labeled with the ATP analog 8-azido-ATP, indicating the presence of an ATP binding site. The coproduction of Anabaena KdpD with E. coli KdpD-CTD decreased E. coli kdpFABC expression in response to K+ limitation in vivo relative to the wild-type KdpD-CTD protein. In vitro experiments revealed that the kinase activity of the E. coli KdpD-CTD was unaffected, but its phosphatase activity increased in the presence of Anabaena KdpD(6His). To our knowledge this is the first report where a heterologous N-terminal domain (Anabaena KdpD) is shown to affect in trans KdpD-CTD (E. coli) activity, which is just opposite to that observed for the KdpD-N-terminal domain of E. coli.
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4

Xue, Ting, Yibo You, De Hong, Haipeng Sun y Baolin Sun. "The Staphylococcus aureus KdpDE Two-Component System Couples Extracellular K+Sensing and Agr Signaling to Infection Programming". Infection and Immunity 79, n.º 6 (21 de marzo de 2011): 2154–67. http://dx.doi.org/10.1128/iai.01180-10.

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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.
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5

Fernandez-Ciruelos, Blanca, Tasneemah Potmis, Vitalii Solomin y Jerry M. Wells. "Cross-talk between QseBC and PmrAB two-component systems is crucial for regulation of motility and colistin resistance in Enteropathogenic Escherichia coli". PLOS Pathogens 19, n.º 12 (7 de diciembre de 2023): e1011345. http://dx.doi.org/10.1371/journal.ppat.1011345.

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The quorum sensing two-component system (TCS) QseBC has been linked to virulence, motility and metabolism regulation in multiple Gram-negative pathogens, including Enterohaemorrhagic Escherichia coli (EHEC), Uropathogenic E. coli (UPEC) and Salmonella enterica. In EHEC, the sensor histidine kinase (HK) QseC detects the quorum sensing signalling molecule AI-3 and also acts as an adrenergic sensor binding host epinephrine and norepinephrine. Downstream changes in gene expression are mediated by phosphorylation of its cognate response regulator (RR) QseB, and ʻcross-talksʼ with non-cognate regulators KdpE and QseF to activate motility and virulence. In UPEC, cross-talk between QseBC and TCS PmrAB is crucial in the regulation and phosphorylation of QseB RR that acts as a repressor of multiple pathways, including motility. Here, we investigated QseBC regulation of motility in the atypical Enteropathogenic E. coli (EPEC) strain O125ac:H6, causative agent of persistent diarrhoea in children, and its possible cross-talk with the KdpDE and PmrAB TCS. We showed that in EPEC QseB acts as a repressor of genes involved in motility, virulence and stress response, and in absence of QseC HK, QseB is likely activated by the non-cognate PmrB HK, similarly to UPEC. We show that in absence of QseC, phosphorylated QseB activates its own expression, and is responsible for the low motility phenotypes seen in a QseC deletion mutant. Furthermore, we showed that KdpD HK regulates motility in an independent manner to QseBC and through a third unidentified party different to its own response regulator KdpE. We showed that PmrAB has a role in iron adaptation independent to QseBC. Finally, we showed that QseB is the responsible for activation of colistin and polymyxin B resistance genes while PmrA RR acts by preventing QseB activation of these resistance genes.
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6

Muccee, Fatima. "In Silico Characterization of Plant Salt Tolerance Promoting KDP Proteins from Alcaligenes xylosoxydans". Plant Protection 7, n.º 3 (27 de diciembre de 2023): 567–77. http://dx.doi.org/10.33804/pp.007.03.4938.

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Soil salinity stress is a detrimental factor in crops production. Conventional methods of soil management and reclamation have been proved useless. On the contrary, exploiting the inherent genes and mechanisms of halotolerant bacteria can bring revolution in agriculture. Present study was designed to characterize ATPase dependent protein complexes kdpFABC and kdpDE in a salt tolerant bacterium Alcaligenes xylosoxydans. This complex enables plants to endure the saline environmental conditions through enhancing the K+ ions influx. For characterization, protein sequences of three isoforms of kdpA, four of kdpB, two of kdpC and one of kdpE were retrieved from Uniprot database. These were analyzed via ProtParam tool, AlphaFold protein database and HDOCK server. Highest affinity for ATP molecule was observed in kdpB confirming its reported function of ATP hydrolysis. All documented proteins were found polar (except kdpE), alkaline (except one isoform of each kdpA and kdpB), thermostable, to exhibit complex 3D structure (except for kdpC and E) and in vitro stability. These properties of subunit proteins can be exploited to engineer the complex and produce osmotolerant transgenic plants
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7

Zhao, Liping, Ting Xue, Fei Shang, Haipeng Sun y Baolin Sun. "Staphylococcus aureus AI-2 Quorum Sensing Associates with the KdpDE Two-Component System To Regulate Capsular Polysaccharide Synthesis and Virulence". Infection and Immunity 78, n.º 8 (24 de mayo de 2010): 3506–15. http://dx.doi.org/10.1128/iai.00131-10.

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ABSTRACT Autoinducer 2 (AI-2) is widely recognized as a signal molecule for intra- and interspecies communication in Gram-negative bacteria, but its signaling function in Gram-positive bacteria, especially in Staphylococcus aureus, remains obscure. Here we reveal the role of LuxS in the regulation of capsular polysaccharide synthesis in S. aureus NCTC8325 and show that AI-2 can regulate gene expression and is involved in some physiological activities in S. aureus as a signaling molecule. Inactivation of luxS in S. aureus NCTC8325 resulted in higher levels of transcription of capsular polysaccharide synthesis genes. The survival rate of the luxS mutant was higher than that of the wild type in both human blood and U937 macrophages. In comparison to the luxS mutant, a culture supplemented with chemically synthesized 4,5-dihydroxy-2,3-pentanedione (DPD), the AI-2 precursor molecule, restored all the parental phenotypes, suggesting that AI-2 has a signaling function in S. aureus. Furthermore, we demonstrated that the LuxS/AI-2 signaling system regulates capsular polysaccharide production via a two-component system, KdpDE, whose function has not yet been clarified in S. aureus. This regulation occurred via the phosphorylation of KdpE binding to the cap promoter.
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8

Sutiono, Samuel, Bettina Siebers y Volker Sieber. "Characterization of highly active 2-keto-3-deoxy-L-arabinonate and 2-keto-3-deoxy-D-xylonate dehydratases in terms of the biotransformation of hemicellulose sugars to chemicals". Applied Microbiology and Biotechnology 104, n.º 16 (21 de junio de 2020): 7023–35. http://dx.doi.org/10.1007/s00253-020-10742-5.

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Abstract2-keto-3-L-arabinonate dehydratase (L-KdpD) and 2-keto-3-D-xylonate dehydratase (D-KdpD) are the third enzymes in the Weimberg pathway catalyzing the dehydration of respective 2-keto-3-deoxy sugar acids (KDP) to α-ketoglutaric semialdehyde (KGSA). The Weimberg pathway has been explored recently with respect to the synthesis of chemicals from L-arabinose and D-xylose. However, only limited work has been done toward characterizing these two enzymes. In this work, several new L-KdpDs and D-KdpDs were cloned and heterologously expressed in Escherichia coli. Following kinetic characterizations and kinetic stability studies, the L-KdpD from Cupriavidus necator (CnL-KdpD) and D-KdpD from Pseudomonas putida (PpD-KdpD) appeared to be the most promising variants from each enzyme class. Magnesium had no effect on CnL-KdpD, whereas increased activity and stability were observed for PpD-KdpD in the presence of Mg2+. Furthermore, CnL-KdpD was not inhibited in the presence of L-arabinose and L-arabinonate, whereas PpD-KdpD was inhibited with D-xylonate (I50 of 75 mM), but not with D-xylose. Both enzymes were shown to be highly active in the one-step conversions of L-KDP and D-KDP. CnL-KdpD converted > 95% of 500 mM L-KDP to KGSA in the first 2 h while PpD-KdpD converted > 90% of 500 mM D-KDP after 4 h. Both enzymes in combination were able to convert 83% of a racemic mixture of D,L-KDP (500 mM) after 4 h, with both enzymes being specific toward the respective stereoisomer. Key points• L-KdpDs and D-KdpDs are specific toward L- and D-KDP, respectively.• Mg2+affected activity and stabilities of D-KdpDs, but not of L-KdpDs.• CnL-KdpD and PpD-KdpD converted 0.5 M of each KDP isomer reaching 95 and 90% yield.• Both enzymes in combination converted 0.5 M racemic D,L-KDP reaching 83% yield.
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9

Agrawal, Ruchi y Deepak Kumar Saini. "Rv1027c–Rv1028c encode functional KdpDE two – Component system in Mycobacterium tuberculosis". Biochemical and Biophysical Research Communications 446, n.º 4 (abril de 2014): 1172–78. http://dx.doi.org/10.1016/j.bbrc.2014.03.066.

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10

Moscoso, Joana A., Hannah Schramke, Yong Zhang, Tommaso Tosi, Amina Dehbi, Kirsten Jung y Angelika Gründling. "Binding of Cyclic Di-AMP to the Staphylococcus aureus Sensor Kinase KdpD Occurs via the Universal Stress Protein Domain and Downregulates the Expression of the Kdp Potassium Transporter". Journal of Bacteriology 198, n.º 1 (20 de julio de 2015): 98–110. http://dx.doi.org/10.1128/jb.00480-15.

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ABSTRACTNucleotide signaling molecules are important intracellular messengers that regulate a wide range of biological functions. The human pathogenStaphylococcus aureusproduces the signaling nucleotide cyclic di-AMP (c-di-AMP). This molecule is common among Gram-positive bacteria and in many organisms is essential for survival under standard laboratory growth conditions. In this study, we investigated the interaction of c-di-AMP with theS. aureusKdpD protein. The sensor kinase KdpD forms a two-component signaling system with the response regulator KdpE and regulates the expression of thekdpDEgenes and thekdpFABCoperon coding for the Kdp potassium transporter components. Here we show that theS. aureusKdpD protein binds c-di-AMP specifically and with an affinity in the micromolar range through its universal stress protein (USP) domain. This domain is located within the N-terminal cytoplasmic region of KdpD, and amino acids of a conserved SXS-X20-FTAXY motif are important for this binding. We further show that KdpD2, a second KdpD protein found in someS. aureusstrains, also binds c-di-AMP, and our bioinformatics analysis indicates that a subclass of KdpD proteins in c-di-AMP-producing bacteria has evolved to bind this signaling nucleotide. Finally, we show that c-di-AMP binding to KdpD inhibits the upregulation of thekdpFABCoperon under salt stress, thus indicating that c-di-AMP is a negative regulator of potassium uptake inS. aureus.IMPORTANCEStaphylococcus aureusis an important human pathogen and a major cause of food poisoning in Western countries. A common method for food preservation is the use of salt to drive dehydration. This study sheds light on the regulation of potassium uptake inStaphylococcus aureus, an important aspect of this bacterium's ability to tolerate high levels of salt. We show that the signaling nucleotide c-di-AMP binds to a regulatory component of the Kdp potassium uptake system and that this binding has an inhibitory effect on the expression of thekdpgenes encoding a potassium transporter. c-di-AMP binds to the USP domain of KdpD, thus providing for the first time evidence for the ability of such a domain to bind a cyclic dinucleotide.
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11

Yang, Ruo-Lan, Chao-Ying Deng, Jin-Wei Wei, Wei He, Ai-Ning Li y Wei Qian. "A Large-Scale Mutational Analysis of Two-Component Signaling Systems of Lonsdalea quercina Revealed that KdpD-KdpE Regulates Bacterial Virulence Against Host Poplar Trees". Molecular Plant-Microbe Interactions® 31, n.º 7 (julio de 2018): 724–36. http://dx.doi.org/10.1094/mpmi-10-17-0248-r.

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Poplar, which is a dominant species in plant communities distributed in the northern hemisphere, is commonly used as a model plant in forestry studies. Poplar production can be inhibited by infections caused by bacteria, including Lonsdalea quercina subsp. populi, which is a gram-negative bacterium responsible for bark canker disease. However, the molecular basis of the pathogenesis remains uncharacterized. In this study, we annotated the two-component signal transduction systems (TCSs) encoded by the L. quercina subsp. populi N-5-1 genome and identified 18 putative histidine kinases and 24 response regulators. A large-scale mutational analysis revealed that 19 TCS genes regulated bacterial virulence against poplar trees. Additionally, the deletion of kdpE or overexpression of kdpD resulted in almost complete loss of bacterial virulence. We observed that kdpE and kdpD formed a bi-cistronic operon. KdpD exhibited autokinase activity and could bind to KdpE (Kd = 5.73 ± 0.64 μM). Furthermore, KdpE is an OmpR family response regulator. A chromatin immunoprecipitation sequencing analysis revealed that KdpE binds to an imperfect palindromic sequence within the promoters of 44 genes, including stress response genes Lqp0434, Lqp3037, and Lqp3270. A comprehensive analysis of TCS functions may help to characterize the regulation of poplar bark canker disease.
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12

Zimmann, Petra, Anne Steinbrügge, Maren Schniederberend, Kirsten Jung y Karlheinz Altendorf. "The Extension of the Fourth Transmembrane Helix of the Sensor Kinase KdpD of Escherichia coli Is Involved in Sensing". Journal of Bacteriology 189, n.º 20 (17 de agosto de 2007): 7326–34. http://dx.doi.org/10.1128/jb.00976-07.

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ABSTRACT The KdpD sensor kinase and the KdpE response regulator control expression of the kdpFABC operon coding for the KdpFABC high-affinity K+ transport system of Escherichia coli. In search of a distinct part of the input domain of KdpD which is solely responsible for K+ sensing, sequences of kdpD encoding the transmembrane region and adjacent N-terminal and C-terminal extensions were subjected to random mutagenesis. Nine KdpD derivatives were identified that had lost tight regulation of kdpFABC expression. They all carried single amino acid replacements located in a region encompassing the fourth transmembrane helix and the adjacent arginine cluster of KdpD. All mutants exhibited high levels of kdpFABC expression regardless of the external K+ concentration. However, 3- to 14-fold induction was observed under extreme K+-limiting conditions and in response to an osmotic upshift when sucrose was used as an osmolyte. These KdpD derivatives were characterized by a reduced phosphatase activity in comparison to the autokinase activity in vitro, which explains constitutive expression. Whereas for wild-type KdpD the autokinase activity and also, in turn, the phosphotransfer activity to KdpE were inhibited by increasing concentrations of K+, both activities were unaffected in the KdpD derivatives. These data clearly show that the extension of the fourth transmembrane helix encompassing the arginine cluster is mainly involved in sensing both K+ limitation and osmotic upshift, which may not be separated mechanistically.
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13

Hamann, Knut, Petra Zimmann y Karlheinz Altendorf. "Reduction of Turgor Is Not the Stimulus for the Sensor Kinase KdpD of Escherichia coli". Journal of Bacteriology 190, n.º 7 (1 de febrero de 2008): 2360–67. http://dx.doi.org/10.1128/jb.01635-07.

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ABSTRACT Stimulus perception by the KdpD/KdpE two-component system of Escherichia coli is still controversial with respect to the nature of the stimulus that is perceived by the sensor kinase KdpD. Limiting potassium concentrations in the medium or high osmolality leads to KdpD/KdpE signal transduction, resulting in kdpFABC expression. It has been hypothesized that changes in turgor are sensed by KdpD through alterations in the physical state of the cytoplasmic membrane. However, in this study the quantitative determination of expression levels of the kdpFABC operon revealed that the system responds very effectively to K+-limiting conditions in the medium but barely and to various degrees to salt and sugar stress. Since the current view of stimulus perception calls for mainly intracellular parameters, which might be sensed by KdpD, we set out to test the cytoplasmic concentrations of ATP, K+, Na+, glutamate, proline, glycine, trehalose, putrescine, and spermidine under K+-limiting conditions. As a first result, the determination of the cytoplasmic volume, which is a prerequisite for such measurements, revealed that a transient shrinkage of the cytoplasmic volume, which is indicative of a reduction in turgor, occurred only under osmotic upshift but not under K+-limiting conditions. Furthermore, the intracellular ATP concentration significantly increased under osmotic upshift, whereas only a slight increase occurred after a potassium downshift. Finally, the cytoplasmic K+ concentration rose severalfold only after an osmotic upshock. For the first time, these data indicate that stimulus perception by KdpD correlates neither with changes in the cytoplasmic volume nor with changes in the intracellular ATP or K+ concentration or those of the other solutes tested. In conclusion, we propose that a reduction in turgor cannot be the stimulus for KdpD.
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14

Polarek, J. W., G. Williams y W. Epstein. "The products of the kdpDE operon are required for expression of the Kdp ATPase of Escherichia coli." Journal of Bacteriology 174, n.º 7 (1992): 2145–51. http://dx.doi.org/10.1128/jb.174.7.2145-2151.1992.

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Parish, Tanya, Debbie A. Smith, Sharon Kendall, Nicola Casali, Gregory J. Bancroft y Neil G. Stoker. "Deletion of Two-Component Regulatory Systems Increases the Virulence of Mycobacterium tuberculosis". Infection and Immunity 71, n.º 3 (marzo de 2003): 1134–40. http://dx.doi.org/10.1128/iai.71.3.1134-1140.2003.

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ABSTRACT Two-component regulatory signal transduction systems are widely distributed among bacteria and enable the organisms to make coordinated changes in gene expression in response to a variety of environmental stimuli. The genome sequence of Mycobacterium tuberculosis contains 11 complete two-component systems, four isolated homologous regulators, and three isolated homologous sensors. We have constructed defined mutations in six of these genes and measured virulence in a SCID mouse model. Mice infected with four of the mutants (deletions of devR, tcrXY, trcS, and kdpDE) died more rapidly than those infected with wild-type bacteria. The other two mutants (narL and Rv3220c) showed no change compared to the wild-type H37Rv strain. The most hypervirulent mutant (devRΔ) also grew more rapidly in the acute stage of infection in immunocompetent mice and in gamma interferon-activated macrophages. These results define a novel class of genes in this pathogen whose presence slows down its multiplication in vivo or increases its susceptibility to host killing mechanisms. Thus, M. tuberculosis actively maintains a balance between its own survival and that of the host.
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16

Epstein, Wolfgang. "The KdpD Sensor Kinase of Escherichia coli Responds to Several Distinct Signals To Turn on Expression of the Kdp Transport System". Journal of Bacteriology 198, n.º 2 (8 de septiembre de 2015): 212–20. http://dx.doi.org/10.1128/jb.00602-15.

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ABSTRACTKdp, one of three saturable K+uptake systems inEscherichia coli, is the system with the highest affinity for K+and the only one whose expression is strongly controlled by medium K+concentration. Expression is controlled by a two-component system of KdpD, the sensor kinase, and KdpE, the response regulator. There is general agreement that expression occurs when the growth rate of cells begins to become limited by K+availability. How K+limitation results in expression has been controversial. Studying the roles of the major components of the growth medium shows that KdpD senses at least two distinct signals inside the cell, those of Na+and NH4+, and it probably senses other monovalent cations in the cell. KdpD does not sense turgor.IMPORTANCEThe expression of the Kdp K+transport system ofE. colioccurs when cells become limited in their growth rate by the availability of K+. Cells sense limited K+and try to compensate by taking up other monovalent cations, particularly Na+and NH4+. These cations are sensed in the cytoplasm by the KdpD response regulator, presumably to stimulate its kinase activity. It is shown that KdpD does not sense turgor, as was suggested earlier.
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17

Malli, Ravi y Wolfgang Epstein. "Expression of the Kdp ATPase Is Consistent with Regulation by Turgor Pressure". Journal of Bacteriology 180, n.º 19 (1 de octubre de 1998): 5102–8. http://dx.doi.org/10.1128/jb.180.19.5102-5108.1998.

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ABSTRACT The kdpFABC operon of Escherichia coliencodes the four protein subunits of the Kdp K+ transport system. Kdp is expressed when growth is limited by the availability of K+. Expression of Kdp is dependent on the products of the adjacent kdpDE operon, which encodes a pair of two-component regulators. Studies with kdp-lac fusions led to the suggestion that change in turgor pressure acts as the signal to express Kdp (L. A. Laimins, D. B. Rhoads, and W. Epstein, Proc. Natl. Acad. Sci. USA 78:464–468, 1981). More recently, effects of compatible solutes, among others, have been interpreted as inconsistent with the turgor model (H. Asha and J. Gowrishankar, J. Bacteriol. 175:4528–4537, 1993). We re-examined the effects of compatible solutes and of medium pH on expression of Kdp in studies in which growth rate was also measured. In all cases, Kdp expression correlated with the K+ concentration when growth began to slow. Making the reasonable but currently untestable assumptions that the reduction in growth rate by K+ limitation is due to a reduction in turgor and that addition of betaine does not increase turgor, we concluded that all of the data on Kdp expression are consistent with control by turgor pressure.
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Ng, Heng Kang, Suat Moi Puah, Cindy Shuan Ju Teh, Nuryana Idris y Kek Heng Chua. "Comparative Transcriptomic Profiling of Pellicle and Planktonic Cells from Carbapenem-Resistant Acinetobacter baumannii". Antibiotics 12, n.º 7 (13 de julio de 2023): 1185. http://dx.doi.org/10.3390/antibiotics12071185.

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Acinetobacter baumannii forms air–liquid interface pellicles that boost its ability to withstand desiccation and increase survival under antibiotic pressure. This study aims to delve into the transcriptomic profiles of pellicle cells from clinical strains of carbapenem-resistant A. baumannii (CRAB). The total RNA was extracted from pellicle cells from three pellicle-forming CRAB strains and planktonic cells from three non-pellicle-forming CRAB strains, subject to RNA sequencing using Illumina HiSeq 2500 system. A transcriptomic analysis between pellicle and planktonic cells, along with differential expression genes (DEGs) analysis and enrichment analysis of annotated COGs, GOs, and KEGGs, was performed. Our analysis identified 366 DEGs in pellicle cells: 162 upregulated genes and 204 downregulated genes. The upregulated ABUW_1624 (yiaY) gene and downregulated ABUW_1550 gene indicated potential involvement in fatty acid degradation during pellicle formation. Another upregulated ABUW_2820 (metQ) gene, encoding the D-methionine transporter system, hinted at its contribution to pellicle formation. The upregulation of two-component systems, CusSR and KdpDE, which implies the regulation of copper and potassium ions in a CRAB pellicle formation was also observed. These findings provide valuable insights into the regulation of gene expression during the formation of pellicles in CRAB, and these are potential targets that may aid in the eradication of CRAB infections.
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19

Matsunaga, James y Mariana L. Coutinho. "Positive Regulation of Leptospira interrogans kdp Expression by KdpE as Demonstrated with a Novel β-Galactosidase Reporter in Leptospira biflexa". Applied and Environmental Microbiology 78, n.º 16 (8 de junio de 2012): 5699–707. http://dx.doi.org/10.1128/aem.00713-12.

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ABSTRACTLeptospirosis is a potentially deadly zoonotic disease that afflicts humans and animals.Leptospira interrogans, the predominant agent of leptospirosis, encounters diverse conditions as it proceeds through its life cycle, which includes stages inside and outside the host. Unfortunately, the number of genetic tools available for examining the regulation of gene expression inL. interrogansis limited. Consequently, little is known about the genetic circuits that control gene expression inLeptospira. To better understand the regulation of leptospiral gene expression, theL. interrogans kdplocus, encoding homologs of the P-type ATPase KdpABC potassium transporter with their KdpD sensors and KdpE response regulators, was selected for analysis. We showed that akdpEmutation inL. interrogansprevented the increase inkdpABCmRNA levels observed in the wild-typeL. interrogansstrain when external potassium levels were low. To confirm that KdpE was a positive regulator ofkdpABCtranscription, we developed a novel approach for constructing chromosomal genetic fusions to the endogenousbgaL(β-galactosidase) gene of the nonpathogenLeptospira biflexa. We demonstrated positive regulation of akdpA′-bgaLfusion inL. biflexaby theL. interrogansKdpE response regulator. A controllipL32′-bgaLfusion was not regulated by KdpE. These results demonstrate the utility of genetic fusions to thebgaLgene ofL. biflexafor examining leptospiral gene regulation.
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20

Jung, Kirsten, Mechthild Krabusch y Karlheinz Altendorf. "Cs+ Induces the kdpOperon of Escherichia coli by Lowering the Intracellular K+ Concentration". Journal of Bacteriology 183, n.º 12 (15 de junio de 2001): 3800–3803. http://dx.doi.org/10.1128/jb.183.12.3800-3803.2001.

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ABSTRACT Cs+ was found to induce expression of thekdpFABC operon, encoding a high-affinity K+uptake system of Escherichia coli. Quantitative expression analyses at the transcriptional and translational levels reveal that CsCl causes much higher induction of kdpFABCthan does NaCl. A decrease of the intracellular K+concentration is found in cells exposed to CsCl. The results indicate that kdpFABC expression is induced when the intracellular K+ concentration is lowered. Moreover, the results imply that the signal transduction cascade mediated by KdpD and KdpE is able to integrate multiple signals.
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21

Freeman, Zoë N., Steve Dorus y Nicholas R. Waterfield. "The KdpD/KdpE Two-Component System: Integrating K+ Homeostasis and Virulence". PLoS Pathogens 9, n.º 3 (28 de marzo de 2013): e1003201. http://dx.doi.org/10.1371/journal.ppat.1003201.

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22

Heermann, Ralf y Kirsten Jung. "The complexity of the ‘simple’ two-component system KdpD/KdpE inEscherichia coli". FEMS Microbiology Letters 304, n.º 2 (marzo de 2010): 97–106. http://dx.doi.org/10.1111/j.1574-6968.2010.01906.x.

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23

Ballal, Anand y Shree K. Apte. "Differential Expression of the Two kdp Operons in the Nitrogen-Fixing Cyanobacterium Anabaena sp. Strain L-31". Applied and Environmental Microbiology 71, n.º 9 (septiembre de 2005): 5297–303. http://dx.doi.org/10.1128/aem.71.9.5297-5303.2005.

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ABSTRACT In several types of bacteria, the Kdp ATPase (comprising of the KdpABC complex) is an inducible, high-affinity potassium transporter that scavenges K+ from the environment. The cyanobacterium Anabaena sp. strain L-31 showed the presence of not one but two distinct kdp operons in its genome. The kdp1 consisted of kdpA1B1G1C1D genes, whereas the kdp2 contained the kdpA2B2G2C2 genes. Among the regulatory genes, the kdpD open reading frame of Anabaena sp. strain L-31 was truncated compared to the kdpD of other bacteria, whereas a kdpE-like gene was absent in the vicinity of the two kdp operons. In response to K+ limitation (<0.05 mM external K+), only kdp2 (and not kdp1) expression could be detected as a 5.3-kb transcript on Northern blots, indicating that kdpA2B2G2C2 genes constitute a polycystronic operon. Unlike E. coli, addition of osmolytes like NaCl, or a change in pH of the medium did not enhance the kdp expression in Anabaena sp. strain L-31. Interestingly, the Anabaena sp. strain L-31 kdp2 operon was strongly induced in response to desiccation stress. The addition of K+ to K+-starved cultures resulted in repression and degradation of kdp2 transcripts. Our results clearly show that kdp2 is the major kdp operon expressed in Anabaena sp. strain L-31 and may play an important role in adaptation to K+ limitation and desiccation stress.
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24

Ballal, Anand, Ralf Heermann, Kirsten Jung, Michael Gaßel, Shree Apte y Karlheinz Altendorf. "A chimeric Anabaena / Escherichia coli KdpD protein (Anacoli KdpD) functionally interacts with E. coli KdpE and activates kdp expression in E. coli". Archives of Microbiology 178, n.º 2 (1 de agosto de 2002): 141–48. http://dx.doi.org/10.1007/s00203-002-0435-1.

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25

Vlisidou, Isabella, Ioannis Eleftherianos, Steve Dorus, Guowei Yang, Richard H. ffrench-Constant, Stuart E. Reynolds y Nick R. Waterfield. "The KdpD/KdpE two-component system of Photorhabdus asymbiotica promotes bacterial survival within M. sexta hemocytes". Journal of Invertebrate Pathology 105, n.º 3 (noviembre de 2010): 352–62. http://dx.doi.org/10.1016/j.jip.2010.09.020.

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26

Heermann, Ralf, Arnim Weber, Bettina Mayer, Melanie Ott, Elisabeth Hauser, Günther Gabriel, Torsten Pirch y Kirsten Jung. "The Universal Stress Protein UspC Scaffolds the KdpD/KdpE Signaling Cascade of Escherichia coli under Salt Stress". Journal of Molecular Biology 386, n.º 1 (febrero de 2009): 134–48. http://dx.doi.org/10.1016/j.jmb.2008.12.007.

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27

Xue, Mei, Muhammad Akmal Raheem, Yi Gu, Huiqi Lu, Xiangjun Song, Jian Tu, Ting Xue y Kezong Qi. "The KdpD/KdpE two-component system contributes to the motility and virulence of avian pathogenic Escherichia coli". Research in Veterinary Science 131 (agosto de 2020): 24–30. http://dx.doi.org/10.1016/j.rvsc.2020.03.024.

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28

Kremling, A., R. Heermann, F. Centler, K. Jung y E. D. Gilles. "Analysis of two-component signal transduction by mathematical modeling using the KdpD/KdpE system of Escherichia coli". Biosystems 78, n.º 1-3 (diciembre de 2004): 23–37. http://dx.doi.org/10.1016/j.biosystems.2004.06.003.

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29

Wolf, S., K. Pflüger-Grau y A. Kremling. "Modeling the Interplay of Pseudomonas putida EIIANtr with the Potassium Transporter KdpFABC". Journal of Molecular Microbiology and Biotechnology 25, n.º 2-3 (2015): 178–94. http://dx.doi.org/10.1159/000381214.

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The nitrogen phosphotransferase system (PTS<sup>Ntr</sup>) of <i>Pseudomonas putida</i> is a key regulatory device that participates in controlling many physiological processes in a posttranscriptional fashion. One of the target functions of the PTS<sup>Ntr</sup> is the regulation of potassium transport. This is mediated by the direct interaction of one of its components with the sensor kinase KdpD of the two-component system controlling transcription of the <i>kdpFABC</i> genes. From a detailed experimental analysis of the activity of the <i>kdpF</i> promoter in <i>P. putida</i> wild-type and <i>pts</i> mutant strains with varying potassium concentrations, we had highly time-resolved data at hand, describing the influence of the PTS<sup>Ntr</sup> on the transcription of the KdpFABC potassium transporter. Here, this data was used to construct a mathematical model based on a black box approach. The model was able to describe the data quantitatively with convincing accuracy. The qualitative interpretation of the model allowed the prediction of two general points describing the interplay between the PTS<sup>Ntr</sup> and the KdpFABC potassium transporter: (1) the influence of cell number on the performance of the <i>kdpF</i> promoter is mainly by dilution by growth and (2) potassium uptake is regulated not only by the activity of the KdpD/KdpE two-component system (in turn influenced by PtsN). An additional controller with integrative behavior is predicted by the model structure. This suggests the presence of a novel physiological mechanism during regulation of potassium uptake with the KdpFABC transporter and may serve as a starting point for further investigations.
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30

Altendorf, K., P. Voelkner y W. Puppe. "The sensor kinase KdpD and the response regulator KdpE control expression of the kdpFABC operon in Escherichia coli". Research in Microbiology 145, n.º 5-6 (enero de 1994): 374–81. http://dx.doi.org/10.1016/0923-2508(94)90084-1.

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31

Rothenbücher, Marina C., Sandra J. Facey, Dorothee Kiefer, Marina Kossmann y Andreas Kuhn. "The Cytoplasmic C-Terminal Domain of the Escherichia coli KdpD Protein Functions as a K+ Sensor". Journal of Bacteriology 188, n.º 5 (1 de marzo de 2006): 1950–58. http://dx.doi.org/10.1128/jb.188.5.1950-1958.2006.

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ABSTRACT The KdpD protein is a K+ sensor kinase located in the cytoplasmic membrane of Escherichia coli. It contains four transmembrane stretches and two short periplasmic loops of 4 and 10 amino acid residues, respectively. To determine which part of KdpD functions as a K+ sensor, genetic variants were constructed with truncations or altered arrangements of the transmembrane segments. All KdpD constructs were tested by complementation of an E. coli kdpD deletion strain for their ability to grow at a K+ concentration of 0.1 mM in the medium. A soluble protein composed of the C-terminal cytoplasmic domain was able to complement the kdpD deletion strain. In addition, analysis of the β-galactosidase activity of an E. coli strain which carries a transcriptional fusion of the upstream region of the kdpFABC operon and a promoterless lacZ gene revealed that this soluble KdpD mutant responds to changes in the K+ concentration in the extracellular medium. The results suggest that the sensing and response functions are both located in the C-terminal domain and might be modulated by the N-terminal domain as well as by membrane anchoring.
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32

Walderhaug, M. O., J. W. Polarek, P. Voelkner, J. M. Daniel, J. E. Hesse, K. Altendorf y W. Epstein. "KdpD and KdpE, proteins that control expression of the kdpABC operon, are members of the two-component sensor-effector class of regulators." Journal of Bacteriology 174, n.º 7 (1992): 2152–59. http://dx.doi.org/10.1128/jb.174.7.2152-2159.1992.

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33

Heermann, Ralf, Karlheinz Altendorf y Kirsten Jung. "The N-terminal Input Domain of the Sensor Kinase KdpD ofEscherichia coliStabilizes the Interaction between the Cognate Response Regulator KdpE and the Corresponding DNA-binding Site". Journal of Biological Chemistry 278, n.º 51 (8 de octubre de 2003): 51277–84. http://dx.doi.org/10.1074/jbc.m303801200.

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34

Karstens, Katja, Christopher P. Zschiedrich, Botho Bowien, Jörg Stülke y Boris Görke. "Phosphotransferase protein EIIANtr interacts with SpoT, a key enzyme of the stringent response, in Ralstonia eutropha H16". Microbiology 160, n.º 4 (1 de abril de 2014): 711–22. http://dx.doi.org/10.1099/mic.0.075226-0.

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EIIANtr is a member of a truncated phosphotransferase (PTS) system that serves regulatory functions and exists in many Proteobacteria in addition to the sugar transport PTS. In Escherichia coli, EIIANtr regulates K+ homeostasis through interaction with the K+ transporter TrkA and sensor kinase KdpD. In the β-Proteobacterium Ralstonia eutropha H16, EIIANtr influences formation of the industrially important bioplastic poly(3-hydroxybutyrate) (PHB). PHB accumulation is controlled by the stringent response and induced under conditions of nitrogen deprivation. Knockout of EIIANtr increases the PHB content. In contrast, absence of enzyme I or HPr, which deliver phosphoryl groups to EIIANtr, has the opposite effect. To clarify the role of EIIANtr in PHB formation, we screened for interacting proteins that co-purify with Strep-tagged EIIANtr from R. eutropha cells. This approach identified the bifunctional ppGpp synthase/hydrolase SpoT1, a key enzyme of the stringent response. Two-hybrid and far-Western analyses confirmed the interaction and indicated that only non-phosphorylated EIIANtr interacts with SpoT1. Interestingly, this interaction does not occur between the corresponding proteins of E. coli. Vice versa, interaction of EIIANtr with KdpD appears to be absent in R. eutropha, although R. eutropha EIIANtr can perfectly substitute its homologue in E. coli in regulation of KdpD activity. Thus, interaction with KdpD might be an evolutionary ‘ancient’ task of EIIANtr that was subsequently replaced by interaction with SpoT1 in R. eutropha. In conclusion, EIIANtr might integrate information about nutritional status, as reflected by its phosphorylation state, into the stringent response, thereby controlling cellular PHB content in R. eutropha.
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35

Cao, Shujin, Yihuai Deng, Bo Yang, Guangyin Lu, Xiangyun Hu, Yajing Mao, Shuanggui Hu y Ziqiang Zhu. "Kernel Density Derivative Estimation of Euler Solutions". Applied Sciences 13, n.º 3 (30 de enero de 2023): 1784. http://dx.doi.org/10.3390/app13031784.

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Conventional Euler deconvolution is widely used for interpreting profile, grid, and ungridded potential field data. The Tensor Euler deconvolution applies additional constraints to the Euler solution using all gravity vectors and the full gravity gradient tensor. These algorithms use a series of different-sized moving windows to yield many solutions that can be employed to estimate the source location from the entire survey area. However, traditional discrimination techniques ignore the interrelation among the Euler solutions, so they cannot be employed to separate adjacent targets. To overcome this difficulty, we introduced multivariate Kernel Density Derivative Estimation (KDDE) as an extension of Kernel Density Estimation, which is a mathematical process to estimate the probability density function of a random variable. The multivariate KDDE was tested on a single cube model, a single cylinder model, and three composite models consisting of two cubes with various separations using gridded data. The probability value calculated by the multivariate KDDE was used to discriminate spurious solutions from the Euler solution dataset and isolate adjacent geological sources. The method was then applied to airborne gravity data from British Columbia, Canada. Then, the results of synthetic models and field data show that the proposed method can successfully locate meaningful geological targets.
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36

Wang, Jie, Kaibin Tian, Dayong Ding, Gang Yang y Xirong Li. "Unsupervised Domain Expansion for Visual Categorization". ACM Transactions on Multimedia Computing, Communications, and Applications 17, n.º 4 (30 de noviembre de 2021): 1–24. http://dx.doi.org/10.1145/3448108.

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Expanding visual categorization into a novel domain without the need of extra annotation has been a long-term interest for multimedia intelligence. Previously, this challenge has been approached by unsupervised domain adaptation (UDA). Given labeled data from a source domain and unlabeled data from a target domain, UDA seeks for a deep representation that is both discriminative and domain-invariant. While UDA focuses on the target domain, we argue that the performance on both source and target domains matters, as in practice which domain a test example comes from is unknown. In this article, we extend UDA by proposing a new task called unsupervised domain expansion (UDE), which aims to adapt a deep model for the target domain with its unlabeled data, meanwhile maintaining the model’s performance on the source domain. We propose Knowledge Distillation Domain Expansion (KDDE) as a general method for the UDE task. Its domain-adaptation module can be instantiated with any existing model. We develop a knowledge distillation-based learning mechanism, enabling KDDE to optimize a single objective wherein the source and target domains are equally treated. Extensive experiments on two major benchmarks, i.e., Office-Home and DomainNet, show that KDDE compares favorably against four competitive baselines, i.e., DDC, DANN, DAAN, and CDAN, for both UDA and UDE tasks. Our study also reveals that the current UDA models improve their performance on the target domain at the cost of noticeable performance loss on the source domain.
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37

Laermann, Vera, Emina Ćudić, Kerstin Kipschull, Petra Zimmann y Karlheinz Altendorf. "The sensor kinase KdpD ofEscherichia colisenses external K+". Molecular Microbiology 88, n.º 6 (28 de mayo de 2013): 1194–204. http://dx.doi.org/10.1111/mmi.12251.

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38

Heermann, Ralf, Karlheinz Altendorf y Kirsten Jung. "The turgor sensor KdpD of Escherichia coli is a homodimer". Biochimica et Biophysica Acta (BBA) - Biomembranes 1415, n.º 1 (diciembre de 1998): 114–24. http://dx.doi.org/10.1016/s0005-2736(98)00181-3.

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39

Bell, Brian L., Nrusingh P. Mohapatra y John S. Gunn. "Regulation of Virulence Gene Transcripts by the Francisella novicida Orphan Response Regulator PmrA: Role of Phosphorylation and Evidence of MglA/SspA Interaction". Infection and Immunity 78, n.º 5 (15 de marzo de 2010): 2189–98. http://dx.doi.org/10.1128/iai.00021-10.

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ABSTRACT Francisella tularensis subsp. tularensis is the etiologic agent of tularemia and has been designated a category A biothreat agent by the CDC. Tularemia is characterized by replication and dissemination within host phagocytes. Intramacrophage growth is dependent upon the regulation of Francisella pathogenicity island (FPI) virulence genes, which is poorly understood. Two-component regulatory systems (TCS) are widely employed by Gram-negative bacteria to monitor and respond to environmental signals. Virulent strains of F. tularensis subsp. tularensis are devoid of classical, tandemly arranged TCS genes, but orphaned members, such as that encoding the response regulator PmrA, have been identified. In the F. novicida model system, previous work has shown that a pmrA mutant shows decreased expression of FPI genes, is deficient for intramacrophage growth, and is avirulent in the mouse model. Here, we determine that phosphorylation aids PmrA binding to regulated promoters pmrA and the FPI-encoded pdpD, and KdpD is the histidine kinase primarily responsible for phosphorylation of PmrA at the aspartic acid at position 51 (D51). A strain expressing PmrA D51A retains some DNA binding but exhibits reduced expression of the PmrA regulon, is deficient for intramacrophage replication, and is attenuated in the mouse model. With regard to virulence gene induction, PmrA coprecipitates with the FPI transcription factors MglA and SspA, which bind RNA polymerase. Together, these data suggest a model of Francisella gene regulation that includes a TCS consisting of KdpD and PmrA. Once phosphorylated, PmrA binds to regulated gene promoters recruiting free or RNA polymerase-bound MglA and SspA to initiate FPI gene transcription.
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40

Toro-Roman, Alejandro, Ti Wu y Ann M. Stock. "A common dimerization interface in bacterial response regulators KdpE and TorR". Protein Science 14, n.º 12 (diciembre de 2005): 3077–88. http://dx.doi.org/10.1110/ps.051722805.

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41

Zimmann, Petra, Wolfram Puppe y Karlheinz Altendorf. "Membrane Topology Analysis of the Sensor Kinase KdpD of Escherichia coli". Journal of Biological Chemistry 270, n.º 47 (noviembre de 1995): 28282–88. http://dx.doi.org/10.1074/jbc.270.47.28282.

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42

Sugiura, Akemi, Kozo Hirokawa, Kyoko Nakashima y Takeshi Mizurto. "Signal-sensing mechanisms of the putative osmosensor KdpD in Escherichia coli". Molecular Microbiology 14, n.º 5 (diciembre de 1994): 929–38. http://dx.doi.org/10.1111/j.1365-2958.1994.tb01328.x.

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43

Nakashima, Kyoko, Akemi Sugiura y Takeshi Mizuno. "Functional Reconstitution of the Putative Escherichia coli Osmosensor, KdpD, into Liposomes1". Journal of Biochemistry 114, n.º 4 (octubre de 1993): 615–21. http://dx.doi.org/10.1093/oxfordjournals.jbchem.a124226.

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44

Jung, Kirsten, Britta Tjaden y Karlheinz Altendorf. "Purification, Reconstitution, and Characterization of KdpD, the Turgor Sensor ofEscherichia coli". Journal of Biological Chemistry 272, n.º 16 (18 de abril de 1997): 10847–52. http://dx.doi.org/10.1074/jbc.272.16.10847.

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45

Kumar, Shivesh, Richard E. Gillilan y Dinesh A. Yernool. "Structure and function of the juxtamembrane GAF domain of potassium biosensor KdpD". Protein Science 29, n.º 9 (17 de agosto de 2020): 2009–21. http://dx.doi.org/10.1002/pro.3920.

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46

Deuschle, M., S. Limbrunner, D. Rother, S. Wahler, M. Chavarría, V. de Lorenzo, A. Kremling y K. Pflüger-Grau. "Interplay of the PtsN (EIIANtr) protein ofPseudomonas putidawith its target sensor kinase KdpD". Environmental Microbiology Reports 7, n.º 6 (27 de agosto de 2015): 899–907. http://dx.doi.org/10.1111/1758-2229.12323.

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47

Hirakawa, Hidetada, Kunihiko Nishino, Takahiro Hirata y Akihito Yamaguchi. "Comprehensive Studies of Drug Resistance Mediated by Overexpression of Response Regulators of Two-Component Signal Transduction Systems in Escherichia coli". Journal of Bacteriology 185, n.º 6 (15 de marzo de 2003): 1851–56. http://dx.doi.org/10.1128/jb.185.6.1851-1856.2003.

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ABSTRACT In Escherichia coli, there are 32 open reading frames (ORFs) that are assumed to be response regulator genes of two-component signal transduction systems on the basis of sequence similarities. We cloned all of these 32 ORFs into a multicopy expression vector and investigated whether or not they confer drug resistance via control of drug resistance determinants. Fifteen of these ORFs, i.e., baeR, citB, cpxR, evgA, fimZ, kdpE, narL, narP, ompR, rcsB, rstA, torR, yedW, yehT, and dcuR, conferred increased single- or multidrug resistance. Two-thirds of them conferred deoxycholate resistance. Five of them, i.e., evgA, baeR, ompR, cpxR, and rcsB, modulated the expression of several drug exporter genes. The drug resistance mediated by evgA, baeR, and cpxR could be assigned to drug exporters by using drug exporter gene knockout strains.
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48

Dutta, Anirudha, Mona Batish y Vijay Parashar. "Structural basis of KdpD histidine kinase binding to the second messenger c-di-AMP". Journal of Biological Chemistry 296 (enero de 2021): 100771. http://dx.doi.org/10.1016/j.jbc.2021.100771.

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49

Stallkamp, Iris, William Dowhan, Karlheinz Altendorf y K. Jung. "Negatively charged phospholipids influence the activity of the sensor kinase KdpD of Escherichia coli". Archives of Microbiology 172, n.º 5 (14 de octubre de 1999): 295–302. http://dx.doi.org/10.1007/s002030050783.

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50

Jung, Kirsten, Ralf Heermann, Marlene Meyer y Karlheinz Altendorf. "Effect of cysteine replacements on the properties of the turgor sensor KdpD of Escherichia coli". Biochimica et Biophysica Acta (BBA) - Biomembranes 1372, n.º 2 (julio de 1998): 311–22. http://dx.doi.org/10.1016/s0005-2736(98)00070-4.

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