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PubMed Central (PMC3 - NLM DTD) (2.996.292 recursos)

Archive of life sciences journal literature at the U.S. National Institutes of Health (NIH), developed and managed by NIH's National Center for Biotechnology Information (NCBI) in the National Library of Medicine (NLM).

Journal of Bacteriology

Mostrando recursos 1 - 20 de 95.579

  1. HexR Controls Glucose-Responsive Genes and Central Carbon Metabolism in Neisseria meningitidis

    Antunes, Ana; Golfieri, Giacomo; Ferlicca, Francesca; Giuliani, Marzia M.; Scarlato, Vincenzo; Delany, Isabel
    Neisseria meningitidis, an exclusively human pathogen and the leading cause of bacterial meningitis, must adapt to different host niches during human infection. N. meningitidis can utilize a restricted range of carbon sources, including lactate, glucose, and pyruvate, whose concentrations vary in host niches. Microarray analysis of N. meningitidis grown in a chemically defined medium in the presence or absence of glucose allowed us to identify genes regulated by carbon source availability. Most such genes are implicated in energy metabolism and transport, and some are implicated in virulence. In particular, genes involved in glucose catabolism were upregulated, whereas genes involved in...

  2. Acinetobacter baumannii Is Dependent on the Type II Secretion System and Its Substrate LipA for Lipid Utilization and In Vivo Fitness

    Johnson, Tanya L.; Waack, Ursula; Smith, Sara; Mobley, Harry; Sandkvist, Maria
    Gram-negative bacteria express a number of sophisticated secretion systems to transport virulence factors across the cell envelope, including the type II secretion (T2S) system. Genes for the T2S components GspC through GspN and PilD are conserved among isolates of Acinetobacter baumannii, an increasingly common nosocomial pathogen that is developing multidrug resistance at an alarming rate. In contrast to most species, however, the T2S genes are dispersed throughout the genome rather than linked into one or two operons. Despite this unique genetic organization, we show here that the A. baumannii T2S system is functional. Deletion of gspD or gspE in A....

  3. Classic Spotlight: Quorum Sensing and the Multicellular Life of Unicellular Organisms

    O'Toole, George A.

  4. Regulation of a Protein Acetyltransferase in Myxococcus xanthus by the Coenzyme NADP+

    Liu, Xin-Xin; Liu, Wei-bing; Ye, Bang-Ce
    NADP+ is a vital cofactor involved in a wide variety of activities, such as redox potential and cell death. Here, we show that NADP+ negatively regulates an acetyltransferase from Myxococcus xanthus, Mxan_3215 (MxKat), at physiologic concentrations. MxKat possesses an NAD(P)-binding domain fused to the Gcn5-type N-acetyltransferase (GNAT) domain. We used isothermal titration calorimetry (ITC) and a coupled enzyme assay to show that NADP+ bound to MxKat and that the binding had strong effects on enzyme activity. The Gly11 residue of MxKat was confirmed to play an important role in NADP+ binding using site-directed mutagenesis and circular dichroism spectrometry. In addition,...

  5. Characterization of an Acinetobacter baumannii lptD Deletion Strain: Permeability Defects and Response to Inhibition of Lipopolysaccharide and Fatty Acid Biosynthesis

    Bojkovic, Jade; Richie, Daryl L.; Six, David A.; Rath, Christopher M.; Sawyer, William S.; Hu, Qijun; Dean, Charles R.
    Lipid A on the Gram-negative outer membrane (OM) is synthesized in the cytoplasm by the Lpx pathway and translocated to the OM by the Lpt pathway. Some Acinetobacter baumannii strains can tolerate the complete loss of lipopolysaccharide (LPS) resulting from the inactivation of early LPS pathway genes such as lpxC. Here, we characterized a mutant deleted for lptD, which encodes an OM protein that mediates the final translocation of fully synthesized LPS to the OM. Cells lacking lptD had a growth defect comparable to that of an lpxC deletion mutant under the growth conditions tested but were more sensitive to...

  6. Antisocial luxO Mutants Provide a Stationary-Phase Survival Advantage in Vibrio fischeri ES114

    Kimbrough, John H.; Stabb, Eric V.
    The squid light organ symbiont Vibrio fischeri controls bioluminescence using two acyl-homoserine lactone pheromone-signaling (PS) systems. The first of these systems to be activated during host colonization, AinS/AinR, produces and responds to N-octanoyl homoserine lactone (C8-AHL). We screened activity of a PainS-lacZ transcriptional reporter in a transposon mutant library and found three mutants with decreased reporter activity, low C8-AHL output, and other traits consistent with low ainS expression. However, the transposon insertions were unrelated to these phenotypes, and genome resequencing revealed that each mutant had a distinct point mutation in luxO. In the wild type, LuxO is phosphorylated by LuxU...

  7. Yersinia Type III Secretion System Master Regulator LcrF

    Schwiesow, Leah; Lam, Hanh; Dersch, Petra; Auerbuch, Victoria
    Many Gram-negative pathogens express a type III secretion (T3SS) system to enable growth and survival within a host. The three human-pathogenic Yersinia species, Y. pestis, Y. pseudotuberculosis, and Y. enterocolitica, encode the Ysc T3SS, whose expression is controlled by an AraC-like master regulator called LcrF. In this review, we discuss LcrF structure and function as well as the environmental cues and pathways known to regulate LcrF expression. Similarities and differences in binding motifs and modes of action between LcrF and the Pseudomonas aeruginosa homolog ExsA are summarized. In addition, we present a new bioinformatics analysis that identifies putative LcrF binding...

  8. Hypothetical Protein BB0569 Is Essential for Chemotaxis of the Lyme Disease Spirochete Borrelia burgdorferi

    Zhang, Kai; Liu, Jun; Charon, Nyles W.; Li, Chunhao
    The Lyme disease spirochete Borrelia burgdorferi has five putative methyl-accepting chemotaxis proteins (MCPs). In this report, we provide evidence that a hypothetical protein, BB0569, is essential for the chemotaxis of B. burgdorferi. While BB0569 lacks significant homology to the canonical MCPs, it contains a conserved domain (spanning residues 110 to 170) that is often evident in membrane-bound MCPs such as Tar and Tsr of Escherichia coli. Unlike Tar and Tsr, BB0569 lacks transmembrane regions and recognizable HAMP and methylation domains and is similar to TlpC, a cytoplasmic chemoreceptor of Rhodobacter sphaeroides. An isogenic mutant of BB0569 constantly runs in one...

  9. Proteome Profiling of the Rhodobacter capsulatus Molybdenum Response Reveals a Role of IscN in Nitrogen Fixation by Fe-Nitrogenase

    Hoffmann, Marie-Christine; Wagner, Eva; Langklotz, Sina; Pfänder, Yvonne; Hött, Sina; Bandow, Julia E.; Masepohl, Bernd
    Rhodobacter capsulatus is capable of synthesizing two nitrogenases, a molybdenum-dependent nitrogenase and an alternative Mo-free iron-only nitrogenase, enabling this diazotroph to grow with molecular dinitrogen (N2) as the sole nitrogen source. Here, the Mo responses of the wild type and of a mutant lacking ModABC, the high-affinity molybdate transporter, were examined by proteome profiling, Western analysis, epitope tagging, and lacZ reporter fusions. Many Mo-controlled proteins identified in this study have documented or presumed roles in nitrogen fixation, demonstrating the relevance of Mo control in this highly ATP-demanding process. The levels of Mo-nitrogenase, NifHDK, and the Mo storage protein, Mop, increased...

  10. NqrM (DUF539) Protein Is Required for Maturation of Bacterial Na+-Translocating NADH:Quinone Oxidoreductase

    Kostyrko, Vitaly A.; Bertsova, Yulia V.; Serebryakova, Marina V.; Baykov, Alexander A.; Bogachev, Alexander V.
    Na+-translocating NADH:quinone oxidoreductase (Na+-NQR) catalyzes electron transfer from NADH to ubiquinone in the bacterial respiratory chain, coupled with Na+ translocation across the membrane. Na+-NQR maturation involves covalent attachment of flavin mononucleotide (FMN) residues, catalyzed by flavin transferase encoded by the nqr-associated apbE gene. Analysis of complete bacterial genomes has revealed another putative gene (duf539, here renamed nqrM) that usually follows the apbE gene and is present only in Na+-NQR-containing bacteria. Expression of the Vibrio harveyi nqr operon alone or with the associated apbE gene in Escherichia coli, which lacks its own Na+-NQR, resulted in an enzyme incapable of Na+-dependent NADH or...

  11. Classic Spotlight: a Window on Multicellular Development

    Stock, Ann M.

  12. Altering the Structure of Carbohydrate Storage Granules in the Cyanobacterium Synechocystis sp. Strain PCC 6803 through Branching-Enzyme Truncations

    Welkie, David G.; Lee, Byung-Hoo; Sherman, Louis A.
    Carbohydrate storage is an important element of metabolism in cyanobacteria and in the chloroplasts of plants. Understanding how to manipulate the metabolism and storage of carbohydrate is also an important factor toward harnessing cyanobacteria for energy production. While most cyanobacteria produce glycogen, some have been found to accumulate polysaccharides in the form of water-insoluble α-glucan similar to amylopectin. Notably, this alternative form, termed “semi-amylopectin,” forms in cyanobacterial species harboring three branching-enzyme (BE) homologs, designated BE1, BE2, and BE3. In this study, mutagenesis of the branching genes found in Synechocystis sp. strain PCC 6803 was performed in order to characterize their...

  13. Structural Similarities and Differences between Two Functionally Distinct SecA Proteins, Mycobacterium tuberculosis SecA1 and SecA2

    Swanson, Stephanie; Ioerger, Thomas R.; Rigel, Nathan W.; Miller, Brittany K.; Braunstein, Miriam; Sacchettini, James C.
    While SecA is the ATPase component of the major bacterial secretory (Sec) system, mycobacteria and some Gram-positive pathogens have a second paralog, SecA2. In bacteria with two SecA paralogs, each SecA is functionally distinct, and they cannot compensate for one another. Compared to SecA1, SecA2 exports a distinct and smaller set of substrates, some of which have roles in virulence. In the mycobacterial system, some SecA2-dependent substrates lack a signal peptide, while others contain a signal peptide but possess features in the mature protein that necessitate a role for SecA2 in their export. It is unclear how SecA2 functions in...

  14. Article of Significant Interest Selected from This Issue by the Editors

  15. The Gonococcal NlpD Protein Facilitates Cell Separation by Activating Peptidoglycan Cleavage by AmiC

    Stohl, Elizabeth A.; Lenz, Jonathan D.; Dillard, Joseph P.; Seifert, H. Steven
    Key steps in bacterial cell division are the synthesis and subsequent hydrolysis of septal peptidoglycan (PG), which allow efficient separation of daughter cells. Extensive studies in the Gram-negative, rod-shaped bacterium Escherichia coli have revealed that this hydrolysis is highly regulated spatially and temporally. Neisseria gonorrhoeae is an obligate Gram-negative, diplococcal pathogen and is the only causative agent of the sexually transmitted infection gonorrhea. We investigated how cell separation proceeds in this diplococcal organism. We demonstrated that deletion of the nlpD gene in strain FA1090 leads to poor growth and to an altered colony and cell morphology. An isopropyl-beta-d-galactopyranoside (IPTG)-regulated nlpD...

  16. Inactivation of Cell Division Protein FtsZ by SulA Makes Lon Indispensable for the Viability of a ppGpp0 Strain of Escherichia coli

    Nazir, Aanisa; Harinarayanan, Rajendran
    The modified nucleotides (p)ppGpp play an important role in bacterial physiology. While the accumulation of the nucleotides is vital for adaptation to various kinds of stress, changes in the basal level modulates growth rate and vice versa. Studying the phenotypes unique to the strain lacking (p)ppGpp (ppGpp0) under overtly unstressed growth conditions may be useful to understand functions regulated by basal levels of (p)ppGpp and its physiological significance. In this study, we show that the ppGpp0 strain, unlike the wild type, requires the Lon protease for cell division and viability in LB. Our results indicate the decrease in FtsZ concentration...

  17. Editorial Board

  18. Erratum for Osorio-Valeriano et al., Biochemical Characterization of the Flagellar Rod Components of Rhodobacter sphaeroides: Properties and Interactions

    Osorio-Valeriano, Manuel; de la Mora, Javier; Camarena, Laura; Dreyfus, Georges

  19. Erratum for Herlihey et al., Modulation of the Lytic Activity of the Dedicated Autolysin for Flagellum Formation SltF by Flagellar Rod Proteins FlgB and FlgF

    Herlihey, Francesca A.; Osorio-Valeriano, Manuel; Dreyfus, Georges; Clarke, Anthony J.

  20. Correction for de la Mora et al., Structural Characterization of the Fla2 Flagellum of Rhodobacter sphaeroides

    de la Mora, Javier; Uchida, Kaoru; Martínez del Campo, Ana; Camarena, Laura; Aizawa, Shin-Ichi; Dreyfus, Georges

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