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https://www.readbyqxmd.com/read/29769380/pneumococcal-metabolic-adaptation-and-colonization-are-regulated-by-the-two-component-regulatory-system-08
#1
Alejandro Gómez-Mejia, Gustavo Gámez, Stephanie Hirschmann, Viktor Kluger, Hermann Rath, Sebastian Böhm, Franziska Voss, Niamatullah Kakar, Lothar Petruschka, Uwe Völker, Reinhold Brückner, Ulrike Mäder, Sven Hammerschmidt
Streptococcus pneumoniae two-component regulatory systems (TCS) enable adaptation and ensure its maintenance in host environments. This study deciphers the impact of TCS08 on pneumococcal gene expression and its role in metabolic and pathophysiological processes. Transcriptome analysis and real-time PCR demonstrated a regulatory effect of TCS08 on genes involved mainly in environmental information processing, intermediary metabolism, and colonization by S. pneumoniae D39 and TIGR4. Striking examples are genes for fatty acid biosynthesis, genes of the arginine deiminase system, and the psa operon encoding the manganese ABC transport system...
June 27, 2018: MSphere
https://www.readbyqxmd.com/read/29668950/secondary-bacterial-pneumonia-by-staphylococcus-aureus-following-influenza-a-infection-is-saer-s-dependent
#2
Timothy R Borgogna, Bennett Hisey, Emily Heitmann, Joshua J Obar, Nicole Meissner, Jovanka M Voyich
S. aureus is a predominant cause of fatal pneumonia following influenza A virus (IAV) infection. Herein we investigate the influence of antecedent IAV infection on S. aureus virulence gene expression. Using a murine model, comparing USA300 and USA300ΔsaeR/S strains, we demonstrate S. aureus pathogenesis following IAV infection is SaeR/S dependent. Furthermore, we show that IAV modulates the lung environment to rapidly up-regulate S. aureus virulence factors containing the SaeR-binding domain. Data demonstrate the pathogen response to IAV infection impacts host outcome and provides evidence that the ability of S...
April 13, 2018: Journal of Infectious Diseases
https://www.readbyqxmd.com/read/29651850/exploring-the-potential-of-a-global-emerging-contaminant-early-warning-network-through-the-use-of-retrospective-suspect-screening-with-high-resolution-mass-spectrometry
#3
Nikiforos A Alygizakis, Saer Samanipour, Juliane Hollender, María Ibáñez, Sarit Kaserzon, Varvara Kokkali, Jan A van Leerdam, Jochen F Mueller, Martijn Pijnappels, Malcolm J Reid, Emma L Schymanski, Jaroslav Slobodnik, Nikolaos S Thomaidis, Kevin V Thomas
A key challenge in the environmental and exposure sciences is to establish experimental evidence of the role of chemical exposure in human and environmental systems. High resolution and accurate tandem mass spectrometry (HRMS) is increasingly being used for the analysis of environmental samples. One lauded benefit of HRMS is the possibility to retrospectively process data for (previously omitted) compounds that has led to the archiving of HRMS data. Archived HRMS data affords the possibility of exploiting historical data to rapidly and effectively establish the temporal and spatial occurrence of newly identified contaminants through retrospective suspect screening...
April 13, 2018: Environmental Science & Technology
https://www.readbyqxmd.com/read/29554425/on-the-excitonic-energy-landscape-of-the-y16f-mutant-of-the-chlorobium-tepidum-fmo-complex-high-resolution-spectroscopic-and-modeling-studies
#4
Anton Khmelnitskiy, Rafael G Saer, Robert E Blankenship, Ryszard J Jankowiak
We report high-resolution (low-temperature) absorption, emission and nonresonant/resonant hole-burned (HB) spectra and results of excitonic calculations using a non-Markovian reduced density matrix theory (with an improved algorithm for parameter optimization in heterogeneous samples) obtained for the Y16F mutant of the Fenna-Matthews-Olson (FMO) trimer from the green sulfur bacterium Chlorobaculum tepidum. We show that the Y16F mutant is a mixture of FMO complexes with three independent low-energy traps (located near 817, 821, and 826 nm), in agreement with measured composite emission and HB spectra...
March 19, 2018: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/29533925/circadian-clock-component-rev-erb%C3%AE-controls-homeostatic-regulation-of-pulmonary-inflammation
#5
Marie Pariollaud, Julie Gibbs, Thomas Hopwood, Sheila Brown, Nicola Begley, Ryan Vonslow, Toryn Poolman, Baoqiang Guo, Ben Saer, D Heulyn Jones, James P Tellam, Stefano Bresciani, Nicholas Co Tomkinson, Justyna Wojno-Picon, Anthony Wj Cooper, Dion A Daniels, Ryan P Trump, Daniel Grant, William Zuercher, Timothy M Willson, Andrew S MacDonald, Brian Bolognese, Patricia L Podolin, Yolanda Sanchez, Andrew Si Loudon, David W Ray
Recent studies reveal that airway epithelial cells are critical pulmonary circadian pacemaker cells, mediating rhythmic inflammatory responses. Using mouse models, we now identify the rhythmic circadian repressor REV-ERB as essential to the mechanism coupling the pulmonary clock to innate immunity, involving both myeloid, and bronchial epithelial cells in temporal gating and determining amplitude of response to inhaled endotoxin. Dual mutation of REV-ERBα and its paralog REV-ERBβ in bronchial epithelia further augmented inflammatory responses and chemokine activation, but also initiated a basal inflammatory state, revealing a critical homeostatic role for REV-ERB proteins in the suppression of the endogenous pro-inflammatory mechanism in un-challenged cells...
March 13, 2018: Journal of Clinical Investigation
https://www.readbyqxmd.com/read/29491349/the-circadian-regulator-bmal1-programmes-responses-to-parasitic-worm-infection-via-a-dendritic-cell-clock
#6
Thomas W Hopwood, Sarah Hall, Nicola Begley, Ruth Forman, Sheila Brown, Ryan Vonslow, Ben Saer, Matthew C Little, Emma A Murphy, Rebecca J Hurst, David W Ray, Andrew S MacDonald, Andy Brass, David A Bechtold, Julie E Gibbs, Andrew S Loudon, Kathryn J Else
Resistance to the intestinal parasitic helminth Trichuris muris requires T-helper 2 (TH 2) cellular and associated IgG1 responses, with expulsion typically taking up to 4 weeks in mice. Here, we show that the time-of-day of the initial infection affects efficiency of worm expulsion, with strong TH 2 bias and early expulsion in morning-infected mice. Conversely, mice infected at the start of the night show delayed resistance to infection, and this is associated with feeding-driven metabolic cues, such that feeding restriction to the day-time in normally nocturnal-feeding mice disrupts parasitic expulsion kinetics...
February 28, 2018: Scientific Reports
https://www.readbyqxmd.com/read/29410445/the-fda-approved-anti-cancer-drugs-streptozotocin-and-floxuridine-reduce-the-virulence-of-staphylococcus-aureus
#7
Won-Sik Yeo, Rekha Arya, Kyeong Kyu Kim, Hyunyoung Jeong, Kyu Hong Cho, Taeok Bae
In Staphylococcus aureus, an important Gram-positive human pathogen, the SaeRS two-component system is essential for the virulence and a good target for the development of anti-virulence drugs. In this study, we screened 12,200 small molecules for Sae inhibitors and identified two anti-cancer drugs, streptozotocin (STZ) and floxuridine (FU), as lead candidates for anti-virulence drug development against staphylococcal infections. As compared with STZ, FU was more efficient in repressing Sae-regulated promoters and protecting human neutrophils from S...
February 6, 2018: Scientific Reports
https://www.readbyqxmd.com/read/29378891/nutritional-regulation-of-the-sae-two-component-system-by-cody-in-staphylococcus-aureus
#8
Kevin D Mlynek, William E Sause, Derek E Moormeier, Marat R Sadykov, Kurt R Hill, Victor J Torres, Kenneth W Bayles, Shaun R Brinsmade
Staphylococcus aureus subverts 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 the S. aureus exoprotein 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 the sae P1 promoter, which suggested direct regulation by this global regulator...
April 15, 2018: Journal of Bacteriology
https://www.readbyqxmd.com/read/29362239/-staphylococcus-aureus-responds-to-the-central-metabolite-pyruvate-to-regulate-virulence
#9
Lamia Harper, Divya Balasubramanian, Elizabeth A Ohneck, William E Sause, Jessica Chapman, Bryan Mejia-Sosa, Tenzin Lhakhang, Adriana Heguy, Aristotelis Tsirigos, Beatrix Ueberheide, Jeffrey M Boyd, Desmond S Lun, Victor J Torres
Staphylococcus aureus is a versatile bacterial pathogen that can cause significant disease burden and mortality. Like other pathogens, S. aureus must adapt to its environment to produce virulence factors to survive the immune responses evoked by infection. Despite the importance of environmental signals for S. aureus pathogenicity, only a limited number of these signals have been investigated in detail for their ability to modulate virulence. Here we show that pyruvate, a central metabolite, causes alterations in the overall metabolic flux of S...
January 23, 2018: MBio
https://www.readbyqxmd.com/read/29236502/redox-conditions-affect-ultrafast-exciton-transport-in-photosynthetic-pigment-protein-complexes
#10
Marco A Allodi, John P Otto, Sara H Sohail, Rafael G Saer, Ryan E Wood, Brian S Rolczynski, Sara C Massey, Po-Chieh Ting, Robert E Blankenship, Gregory S Engel
Pigment-protein complexes in photosynthetic antennae can suffer oxidative damage from reactive oxygen species generated during solar light harvesting. How the redox environment of a pigment-protein complex affects energy transport on the ultrafast light-harvesting timescale remains poorly understood. Using two-dimensional electronic spectroscopy, we observe differences in femtosecond energy-transfer processes in the Fenna-Matthews-Olson (FMO) antenna complex under different redox conditions. We attribute these differences in the ultrafast dynamics to changes to the system-bath coupling around specific chromophores, and we identify a highly-conserved tyrosine/tryptophan chain near the chromophores showing the largest changes...
December 13, 2017: Journal of Physical Chemistry Letters
https://www.readbyqxmd.com/read/29203484/novel-treatment-of-staphylococcus-aureus-device-related-infections-using-fibrinolytic-agents
#11
S Hogan, J P O'Gara, E O'Neill
Staphylococcal infections involving biofilms represent a significant challenge in the treatment of patients with device-related infections. Staphylococcus aureus biofilms have been shown to be SaeRS regulated and dependent on the coagulase-catalyzed conversion of fibrinogen into fibrin on surfaces coated with human plasma. Here we investigated the treatment of staphylococcal biofilm device-related infections by digesting the fibrin biofilm matrix with and without existing antimicrobials. The fibrinolytic agents plasmin, streptokinase, and nattokinase, and TrypLE, a recombinant trypsin-like protease, were used to digest and treat S...
February 2018: Antimicrobial Agents and Chemotherapy
https://www.readbyqxmd.com/read/28950202/hot-rolling-sludge-incineration-suppression-of-pcdd-fs-by-spent-anion-exchange-resins
#12
Shuaixi Xu, Tong Chen, Mengmei Zhang, Alfons Buekens, Yongmei Yu, Yanyan Ling, Zhiliang Chen, Xiaodong Li
Steel industry is the main industrial source of 'dioxins', i.e. polychlorinated dibenzo-p-dioxins (PCDD) and dibenzofurans (PCDF). These arise mainly in the off-gas from sintering plant, yet also other operations, such as continuous casting, and hot and cold rolling could generate albeit minor amounts of dioxins. In this contribution it is verified in how far the incineration of hot rolling sludge (HRS) could contribute to such emissions and, if so, how these could be suppressed at low cost. Spent anion exchange resin (SAER) appeared as a dioxins suppressant during combustion tests of hot rolling sludge in a bench-scale tubular furnace...
February 5, 2018: Journal of Hazardous Materials
https://www.readbyqxmd.com/read/28924032/-staphylococcus-aureus-strain-newman-d2c-contains-mutations-in-major-regulatory-pathways-that-cripple-its-pathogenesis
#13
William E Sause, Richard Copin, Aidan O'malley, Rita Chan, Brian J Morrow, Peter T Buckley, Jeffrey Fernandez, A Simon Lynch, Bo Shopsin, Victor J Torres
Staphylococcus aureus is a major human pathogen that imposes a great burden on the healthcare system. In the development of anti-staphylococcal modalities intended to reduce the burden of staphylococcal disease, it is imperative to select appropriate models of S. aureus strains when assessing the efficacy of novel agents. Here, using whole genome sequencing, we reveal that the commonly used strain Newman D2C from the American Type Culture Collection (ATCC) contains mutations that render the strain essentially avirulent...
September 18, 2017: Journal of Bacteriology
https://www.readbyqxmd.com/read/28765222/role-of-fatty-acid-kinase-in-cellular-lipid-homeostasis-and-saers-dependent-virulence-factor-expression-in-staphylococcus-aureus
#14
Megan E Ericson, Chitra Subramanian, Matthew W Frank, Charles O Rock
The SaeRS two-component system is a master activator of virulence factor transcription in Staphylococcus aureus, but the cellular factors that control its activity are unknown. Fatty acid (FA) kinase is a two-component enzyme system required for extracellular FA uptake and SaeRS activity. Here, we demonstrate the existence of an intracellular nonesterified FA pool in S. aureus that is elevated in strains lacking FA kinase activity. SaeRS-mediated transcription is restored in FA kinase-negative strains when the intracellular FA pool is reduced either by growth with FA-depleted bovine serum albumin to extract the FA into the medium or by the heterologous expression of Neisseria gonorrhoeae acyl-acyl carrier protein synthetase to activate FA for phospholipid synthesis...
August 1, 2017: MBio
https://www.readbyqxmd.com/read/28611950/the-saers-two-component-system-controls-survival-of-staphylococcus-aureus-in-human-blood-through-regulation-of-coagulase
#15
Haiyong Guo, Jeffrey W Hall, Junshu Yang, Yinduo Ji
The SaeRS two-component system plays important roles in regulation of key virulence factors and pathogenicity. In this study, however, we found that the deletion mutation of saeRS enhanced bacterial survival in human blood, whereas complementation of the mutant with SaeRS returned survival to wild-type levels. Moreover, these phenomena were observed in different MRSA genetic background isolates, including HA-MRSA WCUH29, CA-MRSA 923, and MW2. To elucidate which gene(s) regulated by SaeRS contribute to the effect, we conducted a series of complementation studies with selected known SaeRS target genes in trans ...
2017: Frontiers in Cellular and Infection Microbiology
https://www.readbyqxmd.com/read/28588273/myricetin-protects-galleria-mellonella-against-staphylococcus-aureus-infection-and-inhibits-multiple-virulence-factors
#16
L N Silva, G C A Da Hora, T A Soares, M S Bojer, H Ingmer, A J Macedo, D S Trentin
Staphylococcus aureus is an opportunistic pathogen related to a variety of life-threatening infections but for which antimicrobial resistance is liming the treatment options. We report here that myricetin, but not its glycosylated form, can remarkably decrease the production of several S. aureus virulence factors, including adhesion, biofilm formation, hemolysis and staphyloxanthin production, without interfering with growth. Myricetin affects both surface proteins and secreted proteins which indicate that its action is unrelated to inhibition of the agr quorum sensing system...
June 6, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28507069/saers-is-responsive-to-cellular-respiratory-status-and-regulates-fermentative-biofilm-formation-in-staphylococcus-aureus
#17
Ameya A Mashruwala, Casey M Gries, Tyler D Scherr, Tammy Kielian, Jeffrey M Boyd
Biofilms are multicellular communities of microorganisms living as a quorum rather than as individual cells. The bacterial human pathogen Staphylococcus aureus uses oxygen as a terminal electron acceptor during respiration. Infected human tissues are hypoxic or anoxic. We recently reported that impaired respiration elicits a <u>p</u>rogrammed <u>c</u>ell <u>l</u>ysis (PCL) phenomenon in S. aureus leading to the release of cellular polymers that are utilized to form biofilms...
August 2017: Infection and Immunity
https://www.readbyqxmd.com/read/28449877/two-stage-algorithm-vs-commonly-used-approaches-for-the-suspect-screening-of-complex-environmental-samples-analyzed-via-liquid-chromatography-high-resolution-time-of-flight-mass-spectroscopy-a-test-study
#18
Saer Samanipour, Jose A Baz-Lomba, Nikiforos A Alygizakis, Malcolm J Reid, Nikolaos S Thomaidis, Kevin V Thomas
LC-HR-QTOF-MS recently has become a commonly used approach for the analysis of complex samples. However, identification of small organic molecules in complex samples with the highest level of confidence is a challenging task. Here we report on the implementation of a two stage algorithm for LC-HR-QTOF-MS datasets. We compared the performances of the two stage algorithm, implemented via NIVA_MZ_Analyzer™, with two commonly used approaches (i.e. feature detection and XIC peak picking, implemented via UNIFI by Waters and TASQ by Bruker, respectively) for the suspect analysis of four influent wastewater samples...
June 9, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28436648/statistical-variable-selection-an-alternative-prioritization-strategy-during-the-nontarget-analysis-of-lc-hr-ms-data
#19
Saer Samanipour, Malcolm J Reid, Kevin V Thomas
Liquid chromatography coupled to high resolution mass spectrometry (LC-HR-MS) has been one of the main analytical tools for the analysis of small polar organic pollutants in the environment. LC-HR-MS typically produces a large amount of data for a single chromatogram. The analyst is therefore required to perform prioritization prior to nontarget structural elucidation. In the present study, we have combined the F-ratio statistical variable selection and the apex detection algorithms in order to perform prioritization in data sets produced via LC-HR-MS...
May 5, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28289032/vrar-binding-to-the-promoter-region-of-agr-inhibits-its-function-in-vancomycin-intermediate-staphylococcus-aureus-visa-and-heterogeneous-visa
#20
Yuanyuan Dai, Wenjiao Chang, Changcheng Zhao, Jing Peng, Liangfei Xu, Huaiwei Lu, Shusheng Zhou, Xiaoling Ma
Acquisition of vancomycin resistance in Staphylococcus aureus is often accompanied by a reduction in virulence, but the mechanisms underlying this change remain unclear. The present study was undertaken to investigate this process in a clinical heterogeneous vancomycin-intermediate S. aureus (hVISA) strain, 10827; an hVISA reference strain, Mu3; and a VISA reference strain, Mu50, along with their respective series of vancomycin-induced resistant strains. In these strains, increasing MICs of vancomycin were associated with increased expression of the vancomycin resistance-associated regulator gene ( vraR ) and decreased expression of virulence genes ( hla , hlb , and coa ) and virulence-regulated genes (RNAIII, agrA , and saeR )...
May 2017: Antimicrobial Agents and Chemotherapy
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