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Virulence Regulation

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https://www.readbyqxmd.com/read/29780750/the-luxs-ai-2-quorum-sensing-system-of-streptococcus-pneumoniae-is-required-to-cause-disease-and-to-regulate-virulence-and-metabolism-related-genes-in-a-rat-model-of-middle-ear-infection
#1
Mukesh K Yadav, Jorge E Vidal, Yoon Y Go, Shin H Kim, Sung-Won Chae, Jae-Jun Song
Objective: Streptococcus pneumoniae colonizes the nasopharynx of children, and from nasopharynx it could migrate to the middle ear and causes acute otitis media (AOM). During colonization and AOM, the pneumococcus forms biofilms. In vitro biofilm formation requires a functional LuxS/AI-2 quorum-sensing system. We investigated the role of LuxS/AI-2 signaling in pneumococcal middle ear infection, and identified the genes that are regulated by LuxS/AI-2 during pneumococcal biofilm formation. Methods: Streptococcus pneumoniae D39 wild-type and an isogenic D39Δ luxS strain were utilized to evaluate in vitro biofilm formation, and in vivo colonization and epithelial damage using a microtiter plate assay and a rat model of pneumococcal middle ear infection, respectively...
2018: Frontiers in Cellular and Infection Microbiology
https://www.readbyqxmd.com/read/29778469/communications-of-staphylococcus-aureus-and-non-aureus-staphylococcus-species-from-bovine-intramammary-infections-and-teat-apex-colonization
#2
Yasser S Mahmmod, Ilka Christine Klaas, Line Svennesen, Karl Pedersen, Hanne Ingmer
The role of non-aureus staphylococci (NAS) in the risk of acquisition of intramammary infections with Staphylococcus aureus is vague and still under debate. The objectives of this study were to (1) investigate the distribution patterns of NAS species from milk and teat skin in dairy herds with automatic milking systems, and (2) examine if the isolated NAS influences the expression of S. aureus virulence factors controlled by the accessory gene regulator (agr) quorum sensing system. In 8 herds, 14 to 20 cows with elevated somatic cell count were randomly selected for teat skin swabbing and aseptic quarter foremilk samples from right hind and left front quarters...
May 16, 2018: Journal of Dairy Science
https://www.readbyqxmd.com/read/29777151/integrated-proteomics-genomics-metabolomics-approaches-reveal-oxalic-acid-as-pathogenicity-factor-in-tilletia-indica-inciting-karnal-bunt-disease-of-wheat
#3
Vishakha Pandey, Manoj Singh, Dinesh Pandey, Anil Kumar
Tilletia indica incites Karnal bunt (KB) disease in wheat. To date, no KB resistant wheat cultivar could be developed due to non-availability of potential biomarkers related to pathogenicity/virulence for screening of resistant wheat genotypes. The present study was carried out to compare the proteomes of T. indica highly (TiK) and low (TiP) virulent isolates. Twenty one protein spots consistently observed as up-regulated/differential in the TiK proteome were selected for identification by MALDI-TOF/TOF. Identified sequences showed homology with fungal proteins playing essential role in plant infection and pathogen survival, including stress response, adhesion, fungal penetration, invasion, colonization, degradation of host cell wall, signal transduction pathway...
May 18, 2018: Scientific Reports
https://www.readbyqxmd.com/read/29775684/virulence-determinants-biofilm-production-and-antimicrobial-susceptibility-in-staphylococcus-aureus-causing-device-associated-infections-in-a-tunisian-hospital
#4
I Mesrati, M Saidani, M Jemili, S Ferjeni, A Slim, I Boutiba-Ben Boubaker
Staphylococcus aureus is clinically relevant pathogen that cause device-related infections driven by several virulence factors. In this study we characterize S. aureus isolates involved in medical device-related infections in Tunisian patients. Forty consecutive S. aureus strains causing device-related infections (DRI group) and 47 randomly selected S. aureus strains causing non-device-related infections (NDRI group) were collected. All strains were phenotypically screened for antibiotic susceptibility and biofilm forming ability...
May 15, 2018: International Journal of Antimicrobial Agents
https://www.readbyqxmd.com/read/29775484/pseudomonas-aeruginosa-type-iv-minor-pilins-and-pily1-regulate-virulence-by-modulating-fims-algr-activity
#5
Victoria A Marko, Sara L N Kilmury, Lesley T MacNeil, Lori L Burrows
Type IV pili are expressed by a wide range of prokaryotes, including the opportunistic pathogen Pseudomonas aeruginosa. These flexible fibres mediate twitching motility, biofilm maturation, surface adhesion, and virulence. The pilus is composed mainly of major pilin subunits while the low abundance minor pilins FimU-PilVWXE and the putative adhesin PilY1 prime pilus assembly and are proposed to form the pilus tip. The minor pilins and PilY1 are encoded in an operon that is positively regulated by the FimS-AlgR two-component system...
May 18, 2018: PLoS Pathogens
https://www.readbyqxmd.com/read/29775211/proanthocyanidins-will-they-effectively-restrain-conspicuous-bacterial-strains-devolving-on-urinary-tract-infection
#6
REVIEW
Venkataseshan Jagannathan, Pragasam Viswanathan
Struvite or infection stones are one of the major clinical burdens among urinary tract infection, which occur due to the interaction between microbes and urine mineral components. Numerous urinary tract infection (UTI) causing microbes regulate through biofilm formation for survival from host defense, it is often found difficult in its eradication with simple anti-microbial agents and also the chance of recurrence and resistance development is significantly high. Cranberry consumption and maintenance of urinary tract health have been supported by clinical, epidemiological, and mechanistic studies...
May 18, 2018: Journal of Basic Microbiology
https://www.readbyqxmd.com/read/29774203/small-rho-gtpases-and-the-effector-vipa-mediate-the-invasion-of-epithelial-cells-by-filamentous-legionella-pneumophila
#7
Akriti Prashar, María Eugenia Ortiz, Stefanie Lucarelli, Elizabeth Barker, Zohreh Tabatabeiyazdi, Feras Shamoun, Deepa Raju, Costin Antonescu, Cyril Guyard, Mauricio R Terebiznik
Legionella pneumophila (Lp) exhibits different morphologies with varying degrees of virulence. Despite their detection in environmental sources of outbreaks and in respiratory tract secretions and lung autopsies from patients, the filamentous morphotype of Lp remains poorly studied. We previously demonstrated that filamentous Lp invades lung epithelial cells (LECs) and replicates intracellularly in a Legionella containing vacuole. Filamentous Lp activates β1integrin and E-cadherin receptors at the surface of LECs leading to the formation of actin-rich cell membrane structures we termed hooks and membrane wraps...
2018: Frontiers in Cellular and Infection Microbiology
https://www.readbyqxmd.com/read/29774015/comparative-proteomic-and-morphological-change-analyses-of-staphylococcus-aureus-during-resuscitation-from-prolonged-freezing
#8
Biao Suo, Hua Yang, Yuexia Wang, Haipeng Lv, Zhen Li, Chao Xu, Zhilu Ai
When frozen, Staphylococcus aureus survives in a sublethally injured state. However, S. aureus can recover at a suitable temperature, which poses a threat to food safety. To elucidate the resuscitation mechanism of freezing survived S. aureus , we used cells stored at -18°C for 90 days as controls. After resuscitating the survived cells at 37°C, the viable cell numbers were determined on tryptic soy agar with 0.6% yeast extract (TSAYE), and the non-injured-cell numbers were determined on TSAYE supplemented with 10% NaCl...
2018: Frontiers in Microbiology
https://www.readbyqxmd.com/read/29773060/cyclic-peptides-that-govern-signal-transduction-pathways-from-prokaryotes-to-multi-cellular-organisms
#9
Ryan W Mull, Anthony Harrington, Lucia A Sanchez, Yftah Tal-Gan
Cyclic peptide scaffolds are key components of signal transduction pathways in both prokaryotic and eukaryotic organisms since they act as chemical messengers that activate or inhibit specific cognate receptors. In prokaryotic organisms these peptides are utilized in non-essential pathways, such as quorum sensing, that are responsible for virulence and pathogenicity. In the more evolved eukaryotic systems, cyclic peptide hormones play a key role in the regulation of the overall function of multicellular organisms, mainly through the endocrine system...
May 17, 2018: Current Topics in Medicinal Chemistry
https://www.readbyqxmd.com/read/29771915/inactivation-of-bpsl1039-1040-atp-binding-cassette-transporter-reduces-intracellular-survival-in-macrophages-biofilm-formation-and-virulence-in-the-murine-model-of-burkholderia-pseudomallei-infection
#10
Peechanika Pinweha, Pornpan Pumirat, Jon Cuccui, Niramol Jitprasutwit, Veerachat Muangsombut, Varintip Srinon, Usa Boonyuen, Parameth Thiennimitr, Paiboon Vattanaviboon, Felipe Cia, Sam Willcocks, Gregory J Bancroft, Brendan W Wren, Sunee Korbsrisate
Burkholderia pseudomallei, a gram-negative intracellular bacillus, is the causative agent of a tropical infectious disease called melioidosis. Bacterial ATP-binding cassette (ABC) transporters import and export a variety of molecules across bacterial cell membranes. At present, their significance in B. pseudomallei pathogenesis is poorly understood. We report here characterization of the BPSL1039-1040 ABC transporter. B. pseudomallei cultured in M9 medium supplemented with nitrate, demonstrated that BPSL1039-1040 is involved in nitrate transport for B...
2018: PloS One
https://www.readbyqxmd.com/read/29771143/cell-envelope-lipids-in-the-pathophysiology-of-mycobacterium-tuberculosis
#11
Parul Singh, Nagender Rao Rameshwaram, Sudip Ghosh, Sangita Mukhopadhyay
Mycobacterium tuberculosis is an intracellular bacterium that persists and replicates inside macrophages. The bacterium possesses an unusual lipid-rich cell envelope that provides a hydrophobic impermeable barrier against many environmental stressors and allows it to survive extremely hostile intracellular surroundings. Since the lipid-rich envelope is crucial for M. tuberculosis virulence, the components of the cell wall lipid biogenesis pathways constitute an attractive target for the development of vaccines and antimycobacterial chemotherapeutics...
May 17, 2018: Future Microbiology
https://www.readbyqxmd.com/read/29769740/identification-of-a-s-aureus-virulence-factor-by-activity-based-protein-profiling-abpp
#12
Christian S Lentz, Jessica R Sheldon, Lisa A Crawford, Rachel Cooper, Megan Garland, Manuel R Amieva, Eranthie Weerapana, Eric P Skaar, Matthew Bogyo
Serine hydrolases play diverse roles in regulating host-pathogen interactions in a number of organisms, yet few have been characterized in the human pathogen Staphylococcus aureus. Here we describe a chemical proteomic screen that identified ten previously uncharacterized S. aureus serine hydrolases that mostly lack human homologs. We termed these enzymes fluorophosphonate-binding hydrolases (FphA-J). One hydrolase, FphB, can process short fatty acid esters, exhibits increased activity in response to host cell factors, is located predominantly on the bacterial cell surface in a subset of cells, and is concentrated in the division septum...
May 16, 2018: Nature Chemical Biology
https://www.readbyqxmd.com/read/29769610/blsa-integrates-light-and-temperature-signals-into-iron-metabolism-through-fur-in-the-human-pathogen-acinetobacter-baumannii
#13
Marisel R Tuttobene, Pamela Cribb, María Alejandra Mussi
Light modulates global features of the important human pathogen Acinetobacter baumannii lifestyle including metabolism, tolerance to antibiotics and virulence, most of which depend on the short BLUF-type photoreceptor BlsA. In this work, we show that the ability to circumvent iron deficiency is also modulated by light at moderate temperatures, and disclose the mechanism of signal transduction by showing that BlsA antagonizes the functioning of the ferric uptake regulator (Fur) in a temperature-dependent manner...
May 16, 2018: Scientific Reports
https://www.readbyqxmd.com/read/29769603/components-of-a-new-gene-family-of-ferroxidases-involved-in-virulence-are-functionally-specialized-in-fungal-dimorphism
#14
María Isabel Navarro-Mendoza, Carlos Pérez-Arques, Laura Murcia, Pablo Martínez-García, Carlos Lax, Marta Sanchis, Javier Capilla, Francisco E Nicolás, Victoriano Garre
Mucormycosis is an emerging angio-invasive infection caused by Mucorales that presents unacceptable mortality rates. Iron uptake has been related to mucormycosis, since serum iron availability predisposes the host to suffer this infection. In addition, iron uptake has been described as a limiting factor that determines virulence in other fungal infections, becoming a promising field to study virulence in Mucorales. Here, we identified a gene family of three ferroxidases in Mucor circinelloides, fet3a, fet3b and fet3c, which are overexpressed during infection in a mouse model for mucormycosis, and their expression in vitro is regulated by the availability of iron in the culture media and the dimorphic state...
May 16, 2018: Scientific Reports
https://www.readbyqxmd.com/read/29769380/pneumococcal-metabolic-adaptation-and-colonization-are-regulated-by-the-two-component-regulatory-system-08
#15
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/29769379/activation-of-bacterial-histidine-kinases-insights-into-the-kinetics-of-the-cis-autophosphorylation-mechanism
#16
Gaurav D Sankhe, Narendra M Dixit, Deepak K Saini
Two-component signaling systems (TCSs) are central to bacterial adaptation. However, the mechanisms underlying the reactions involving TCS proteins and their reaction rates are largely undetermined. Here, we employed a combined experimental and theoretical approach to elucidate the kinetics of autophosphorylation of three histidine kinases (HKs) of Mycobacterium tuberculosis , viz. , MtrB, PrrB, and PhoR, all known to play a role in regulating its virulence. Using wild-type and mutant proteins, we performed dimerization assays, thermophoretic-affinity measurements, and competition-based phosphorylation assays to establish that for HK, MtrB autophosphorylation occurs in cis , similar to what has been proposed for the PhoR and PrrB HKs...
June 27, 2018: MSphere
https://www.readbyqxmd.com/read/29768466/core-non-coding-rnas-of-piscirickettsia-salmonis
#17
Cristopher Segovia, Raul Arias-Carrasco, Alejandro J Yañez, Vinicius Maracaja-Coutinho, Javier Santander
Piscirickettsia salmonis, a fastidious Gram-negative intracellular facultative bacterium, is the causative agent o Piscirickettsiosis. P. salmonis has broad host range with a nearly worldwide distribution, causing significant mortality. The molecular regulatory mechanisms of P. salmonis pathogenesis are relatively unknown, mainly due to its difficult in vitro culture and genomic differences between genogroups. Bacterial non-coding RNAs (ncRNAs) are important post-transcriptional regulators of bacterial physiology and virulence that are predominantly transcribed from intergenic regions (trans-acting) or antisense strand of open reading frames (cis-acting)...
2018: PloS One
https://www.readbyqxmd.com/read/29768135/seeing-the-light-the-roles-of-red-and-blue-light-sensing-in-plant-microbes
#18
Gwyn A Beattie, Bridget M Hatfield, Haili Dong, Regina S McGrane
Plants collect, concentrate, and conduct light throughout their tissues, thus enhancing light availability to their resident microbes. This review explores the role of photosensing in the biology of plant-associated bacteria and fungi, including the molecular mechanisms of red-light sensing by phytochromes and blue-light sensing by LOV (light-oxygen-voltage)-domain proteins in these microbes. Bacteriophytochromes function as major drivers of the bacterial transcriptome and mediate light-regulated suppression of virulence, motility, and conjugation in some phytopathogens and light-regulated induction of the photosynthetic apparatus in a stem-nodulating symbiont...
May 16, 2018: Annual Review of Phytopathology
https://www.readbyqxmd.com/read/29765621/biofilm-inhibition-and-pathogenicity-attenuation-in-bacteria-by-proteus-mirabilis
#19
Shichen Yu, Xiaoshan Zhu, Jin Zhou, Zhonghua Cai
Biofilms play an important role in the antibiotic resistance of encased bacteria, and biofilm formation is regulated by quorum sensing (QS). Inhibiting the QS system may, therefore, degrade the integrity of a biofilm and expose the bacterial pathogens within it to the deleterious effects of molecules such as antibiotics. Moreover, the use of QS inhibitors (QSIs) may provide a novel approach for treating bacterial infections of aquacultures. In the present study, the bacterium Proteus mirabilis was identified as a potential producer of QSIs...
April 2018: Royal Society Open Science
https://www.readbyqxmd.com/read/29765020/changes-in-genome-organization-of-parasite-specific-gene-families-during-the-plasmodium-transmission-stages
#20
Evelien M Bunnik, Kate B Cook, Nelle Varoquaux, Gayani Batugedara, Jacques Prudhomme, Anthony Cort, Lirong Shi, Chiara Andolina, Leila S Ross, Declan Brady, David A Fidock, Francois Nosten, Rita Tewari, Photini Sinnis, Ferhat Ay, Jean-Philippe Vert, William Stafford Noble, Karine G Le Roch
The development of malaria parasites throughout their various life cycle stages is coordinated by changes in gene expression. We previously showed that the three-dimensional organization of the Plasmodium falciparum genome is strongly associated with gene expression during its replication cycle inside red blood cells. Here, we analyze genome organization in the P. falciparum and P. vivax transmission stages. Major changes occur in the localization and interactions of genes involved in pathogenesis and immune evasion, host cell invasion, sexual differentiation, and master regulation of gene expression...
May 15, 2018: Nature Communications
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