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Virulence Regulation

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https://www.readbyqxmd.com/read/28224117/perc-manipulates-metabolism-and-surface-antigens-in-enteropathogenic-escherichia-coli
#1
Jay L Mellies, Amy Platenkamp, Jossef Osborn, Lily Ben-Avi
Enteropathogenic Escherichia coli is an important cause of profuse, watery diarrhea in infants living in developing regions of the world. Typical strains of EPEC (tEPEC) possess a virulence plasmid, while related clinical isolates that lack the pEAF plasmid are termed atypical EPEC (aEPEC). tEPEC and aEPEC tend to cause acute vs. more chronic type infections, respectively. The pEAF plasmid encodes an attachment factor as well as a regulatory operon, perABC. PerC, a poorly understood regulator, was previously shown to regulate expression of the type III secretion system through Ler...
2017: Frontiers in Cellular and Infection Microbiology
https://www.readbyqxmd.com/read/28223461/identification-of-a-pseudomonas-aeruginosa-pao1-dna-methyltransferase-its-targets-and-physiological-roles
#2
Sebastian Doberenz, Denitsa Eckweiler, Olga Reichert, Vanessa Jensen, Boyke Bunk, Cathrin Spröer, Adrian Kordes, Emanuela Frangipani, Khai Luong, Jonas Korlach, Stephan Heeb, Jörg Overmann, Volkhard Kaever, Susanne Häussler
DNA methylation is widespread among prokaryotes, and most DNA methylation reactions are catalyzed by adenine DNA methyltransferases, which are part of restriction-modification (R-M) systems. R-M systems are known for their role in the defense against foreign DNA; however, DNA methyltransferases also play functional roles in gene regulation. In this study, we used single-molecule real-time (SMRT) sequencing to uncover the genome-wide DNA methylation pattern in the opportunistic pathogen Pseudomonas aeruginosa PAO1...
February 21, 2017: MBio
https://www.readbyqxmd.com/read/28223451/mycobacterium-tuberculosis-proteasome-accessory-factor-a-pafa-can-transfer-prokaryotic-ubiquitin-like-protein-pup-between-substrates
#3
Susan Zhang, Kristin E Burns-Huang, Guido V Janssen, Huilin Li, Huib Ovaa, Lizbeth Hedstrom, K Heran Darwin
The protein degradation machinery of Mycobacterium tuberculosis includes a proteasome and a ubiquitin-like protein (Pup). Proteasome accessory factor A (PafA) attaches Pup to proteins to target them for degradation by the proteasome. Free Pup is unstable and never observed in extracts of M. tuberculosis, an observation that led us to hypothesize that PafA may need alternative sources of Pup. Here, we show that PafA can move Pup from one proteasome substrate, inositol 1-phosphate synthetase (Ino1), to two different proteins, malonyl coenzyme A (CoA)-acyl carrier protein transacylase (FabD) and lonely guy (Log)...
February 21, 2017: MBio
https://www.readbyqxmd.com/read/28223347/intact-pneumococci-trigger-transcription-of-interferon-related-genes-in-human-monocytes-while-fragmented-autolyzed-bacteria-subvert-this-response
#4
Susann Skovbjerg, Rickard Nordén, Anna Martner, Ebba Samuelsson, Lars Hynsjö, Agnes E Wold
A peculiar trait of pneumococci (Streptococcus pneumoniae) is their propensity to undergo spontaneous lysis during stationary growth due to activation of the enzyme autolysin (LytA) that fragments the peptidoglycan cell wall. The fragments that are generated upon autolysis impair phagocytosis and reduce production of IL-12 and IFN-γ by human leukocytes in response to intact pneumococci, thereby impeding crucial host defenses. The objective was to identify additional monocyte genes whose transcription is induced by intact pneumococci, and subverted by autolyzed bacteria...
February 21, 2017: Infection and Immunity
https://www.readbyqxmd.com/read/28221718/quantitative-analysis-of-shigella-flexneri-protein-expression-under-acid-stress
#5
Kaiwen Yu, Zhen Wang, Fan Zhou, Jiezhang Jiang, Yanhua Liu, Mo Hu, Xiaoyun Liu
As an important foodborne pathogen, Shigella flexneri can cause widespread enteric infection with bacteria as few as hundreds. This is, at least in part, attributed to its robust anti-acid strategies because passage through the highly acidic human digestive tract is a prerequisite for successful bacterial infection. Nevertheless, our understanding of these mechanisms and the impact of acid stress on Shigella protein expression still remains largely incomplete. Herein we conducted a proteomic survey of Shigella spp...
February 21, 2017: Proteomics
https://www.readbyqxmd.com/read/28220899/group-a-streptococcal-m1-protein-provides-resistance-against-the-antimicrobial-activity-of-histones
#6
Simon Döhrmann, Christopher N LaRock, Ericka L Anderson, Jason N Cole, Brinda Ryali, Chelsea Stewart, Poochit Nonejuie, Joe Pogliano, Ross Corriden, Partho Ghosh, Victor Nizet
Histones are essential elements of chromatin structure and gene regulation in eukaryotes. An unexpected attribute of these nuclear proteins is their antimicrobial activity. A framework for histone release and function in host defense in vivo was revealed with the discovery of neutrophil extracellular traps, a specialized cell death process in which DNA-based structures containing histones are extruded to ensnare and kill bacteria. Investigating the susceptibility of various Gram-positive pathogens to histones, we found high-level resistance by one leading human pathogen, group A Streptococcus (GAS)...
February 21, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28220120/neutrophil-extracellular-traps-and-its-implications-in-inflammation-an-overview
#7
REVIEW
Vidal Delgado-Rizo, Marco A Martínez-Guzmán, Liliana Iñiguez-Gutierrez, Alejandra García-Orozco, Anabell Alvarado-Navarro, Mary Fafutis-Morris
In addition to physical barriers, neutrophils are considered a part of the first line of immune defense. They can be found in the bloodstream, with a lifespan of 6-8 h, and in tissue, where they can last up to 7 days. The mechanisms that neutrophils utilize for host defense are phagocytosis, degranulation, cytokine production, and, the most recently described, neutrophil extracellular trap (NET) production. NETs are DNA structures released due to chromatin decondensation and spreading, and they thus occupy three to five times the volume of condensed chromatin...
2017: Frontiers in Immunology
https://www.readbyqxmd.com/read/28217742/piericidin-a1-blocks-yersinia-ysc-type-iii-secretion-system-needle-assembly
#8
Jessica M Morgan, Miles C Duncan, Kevin S Johnson, Andreas Diepold, Hanh Lam, Allison J Dupzyk, Lexi R Martin, Weng Ruh Wong, Judith P Armitage, Roger G Linington, Victoria Auerbuch
The type III secretion system (T3SS) is a bacterial virulence factor expressed by dozens of Gram-negative pathogens but largely absent from commensals. The T3SS is an attractive target for antimicrobial agents that may disarm pathogenic bacteria while leaving commensal populations intact. We previously identified piericidin A1 as an inhibitor of the Ysc T3SS in Yersinia pseudotuberculosis. Piericidins were first discovered as inhibitors of complex I of the electron transport chain in mitochondria and some bacteria...
January 2017: MSphere
https://www.readbyqxmd.com/read/28217110/intra-species-and-inter-kingdom-signaling-of-legionella-pneumophila
#9
REVIEW
Ramon Hochstrasser, Hubert Hilbi
The ubiquitous Gram-negative bacterium Legionella pneumophila parasitizes environ mental amoebae and, upon inhalation, replicates in alveolar macrophages, thus causing a life-threatening pneumonia called "Legionnaires' disease." The opportunistic pathogen employs a bi-phasic life cycle, alternating between a replicative, non-virulent phase and a stationary, transmissive/virulent phase. L. pneumophila employs the Lqs (Legionella quorum sensing) system as a major regulator of the growth phase switch. The Lqs system comprises the autoinducer synthase LqsA, the homologous sensor kinases LqsS and LqsT, as well as a prototypic response regulator termed LqsR...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28216386/serotonin-disturbs-colon-epithelial-tolerance-of-commensal-e-coli-by-increasing-nox-2-derived-superoxide
#10
Suhrid Banskota, Sushil Chandra Regmi, Jaya Gautam, Pallavi Gurung, Yu-Jeong Lee, Sae Kwang Ku, Jin-Hyung Lee, Jintae Lee, Hyeun Wook Chang, Sang Joon Park, Jung-Ae Kim
Adherent-invasive E. coli colonization and Toll-like receptor (TLR) expression are increased in the gut of inflammatory bowel disease (IBD) patients. However, the underlying mechanism of such changes has not been determined. In the current study, it was examined whether gut serotonin (5-hydroxytryptamine, 5-HT) can induce adherent-invasive E. coli colonization and increase TLR expression. In a co-culture system, commensal E. coli strain (BW25113, BW) adhered minimally to colon epithelial cells, but this was significantly enhanced by 5-HT to the level of a pathogenic strain (EDL933)...
February 16, 2017: Free Radical Biology & Medicine
https://www.readbyqxmd.com/read/28213905/a-ten-gene-containing-genomic-island-determines-flagellin-glycosylation-implication-for-its-regulatory-role-in-motility-and-virulence-of-xanthomonas-oryzae-pv-oryzae
#11
Chao Yu, Huamin Chen, Fang Tian, Fenghuan Yang, Xiaochen Yuan, Ching-Hong Yang, Chenyang He
Flagellin glycosylation plays crucial roles in flagellar assembly, motility and virulence in several pathogenic bacteria. However, little is known about the genetic determinants and biological functions of flagellin glycosylation in Xanthomonas oryzae pv. oryzae (Xoo), the causal pathogen of bacterial blight of rice. Here, the structure, regulation and functions of a ten-gene cluster gigX (glycosylation island genes of Xoo), which was embedded in a flagellar regulon were characterized. gigX1 through gigX10, encoded putative enzymes or proteins involved in glycan biosynthesis and transfer, including a nucleotide sugar transaminase, an acyl-carrier protein (ACP), a 3-oxoacyl-ACP synthase, a 3-oxoacyl-ACP reductase, a dehydrogenase, an acetyltransferase, a ring hydroxylating dioxygenase, a hypothetical protein, a methyltransferanse, and a glycosyltransferase, respectively...
February 18, 2017: Molecular Plant Pathology
https://www.readbyqxmd.com/read/28212376/the-legionella-pneumophila-genome-evolved-to-accommodate-multiple-regulatory-mechanisms-controlled-by-the-csra-system
#12
Tobias Sahr, Christophe Rusniok, Francis Impens, Giulia Oliva, Odile Sismeiro, Jean-Yves Coppée, Carmen Buchrieser
The carbon storage regulator protein CsrA regulates cellular processes post-transcriptionally by binding to target-RNAs altering translation efficiency and/or their stability. Here we identified and analyzed the direct targets of CsrA in the human pathogen Legionella pneumophila. Genome wide transcriptome, proteome and RNA-Co-immunoprecipitaion followed by deep sequencing of a wild type and a csrA mutant strain identified 479 RNAs with potential CsrA interaction sites located in the untranslated and/or coding regions of mRNAs or of known non-coding sRNAs...
February 17, 2017: PLoS Genetics
https://www.readbyqxmd.com/read/28209897/host-cell-attachment-elicits-posttranscriptional-regulation-in-infecting-enteropathogenic-bacteria
#13
Naama Katsowich, Netanel Elbaz, Ritesh Ranjan Pal, Erez Mills, Simi Kobi, Tamar Kahan, Ilan Rosenshine
The mechanisms by which pathogens sense the host and respond by remodeling gene expression are poorly understood. Enteropathogenic Escherichia coli (EPEC), the cause of severe intestinal infection, employs a type III secretion system (T3SS) to inject effector proteins into intestinal epithelial cells. These effectors subvert host cell processes to promote bacterial colonization. We show that the T3SS also functions to sense the host cell and to trigger in response posttranscriptional remodeling of gene expression in the bacteria...
February 17, 2017: Science
https://www.readbyqxmd.com/read/28209712/mycobacterium-tuberculosis-esxl-inhibit-mhc-ii-expression-by-promoting-hypermethylation-in-class-ii-transactivator-loci-in-macrophages
#14
Srabasti Sengupta, Saba Naz, Ishani Das, Abdul Ahad, Avinash Padhi, Sumanta Naik, Geetanjali Ganguli, Kaliprasad Patnaik, Sunil Kumar Raghav, Vinay Nandicoori, Avinash Sonawane
Mycobacterium tuberculosis (Mtb) is known to modulate the host immune responses to facilitate its persistence inside the host cells. One of the key mechanisms includes repression of class-II transactivator (CIITA) and MHC-II expression in infected macrophages. However, the precise mechanism of CIITA and MHC-II down-regulation is not well studied. Mtb 6-kDa early secretory antigenic target (ESAT-6) is a known potent virulence and antigenic determinant. Mtb genome encodes 23 such ESAT-6 family proteins. We herein report that Mtb and M...
February 16, 2017: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/28202392/sophisticated-regulation-of-transcriptional-factors-by-the-bacterial-phosphoenolpyruvate-sugar-phosphotransferase-system
#15
REVIEW
Anne Galinier, Josef Deutscher
The phosphoenolpyruvate:sugar phosphotransferase system (PTS) is a carbohydrate transport and phosphorylation system present in bacteria of all different phyla and in archaea. It is usually composed of three proteins or protein complexes, enzyme I, HPr and enzyme II, which are phosphorylated at histidine or cysteine residues. However, in many bacteria, HPr can also be phosphorylated at a serine residue. The PTS functions not only as carbohydrate transporter, but also regulates numerous cellular processes by either phosphorylating its target proteins or by interacting with them in a phosphorylation-dependent manner...
February 12, 2017: Journal of Molecular Biology
https://www.readbyqxmd.com/read/28198348/down-regulation-of-pe11-a-cell-wall-associated-esterase-enhances-the-biofilm-growth-of-mycobacterium-tuberculosis-and-reduces-cell-wall-virulence-lipid-levels
#16
Shivangi Rastogi, Amit Kumar Singh, Garima Pant, Kalyan Mitra, Koneni V Sashidhara, Manju Y Krishnan
PE11 (Rv1169c or LipX) is a cell wall associated esterase/lipase of Mycobacterium tuberculosis (Mtb). Evidences suggest that PE11 is expressed by Mtb both in vitro and in vivo. Previous studies have shown that PE11 leads to modification in cell wall lipid content and enhanced virulence when expressed in the non-pathogenic surrogate Mycobacterium smegmatis. Since cell wall lipids often play different roles in pathogenic and non-pathogenic mycobacteria, we investigated the role of PE11 in its host, Mtb. Mtb with lowered expression of PE11 (PE11 knock-down) displayed significant changes in colony morphology and cell wall lipid profile, confirming the role of PE11 in cell wall architecture...
January 2017: Microbiology
https://www.readbyqxmd.com/read/28196877/using-quantitative-mass-spectrometry-to-better-understand-the-influence-of-genetics-and-nutritional-perturbations-on-the-virulence-potential-of-staphylococcus-aureus
#17
Jessica R Chapman, Divya Balasubramanian, Kayan Tam, Manor Askenazi, Richard Copin, Bo Shopsin, Victor J Torres, Beatrix Ueberheide
Staphylococcus aureus (Sa) is the leading cause of a variety of bacterial infections ranging from superficial skin infections to invasive and life threatening diseases such as septic bacteremia, necrotizing pneumonia, and endocarditis. The success of Sa as a human pathogen is due to its ability to adapt to the environment by changing expression, production, or secretion of virulence factors. Although Sa immune evasion is well-studied, the regulation of virulence factors under different nutrient and growth conditions is still not well understood...
February 14, 2017: Molecular & Cellular Proteomics: MCP
https://www.readbyqxmd.com/read/28196869/structural-insights-unravel-the-zymogenic-mechanism-of-the-virulence-factor-gingipain-k-from-porphyromonas-gingivalis-a-causative-agent-of-gum-disease-from-the-human-oral-microbiome
#18
Anja Pomowski, Isabel Uson, Zuzanna M Nowakowska, Florian Veillard, Maryta N Sztukowska, Tibisay Guevara, Theodoros Goulas, Danuta Mizgalska, Magdalena L Nowak, Barbara A Potempa, James A Huntington, Jan Potempa, F Xavier Gomis-Ruth
Skewing of the human oral microbiome causes dysbiosis and preponderance of bacteria such as Porphyromonas gingivalis, the main etiological agent of periodontitis. P. gingivalis secretes proteolytic gingipains (Kgp and RgpA/B) as zymogens inhibited by a pro-domain that is removed during extracellular activation. Unraveling the molecular mechanism of Kgp zymogenicity is essential to design inhibitors blocking its activity. Here, we found that the isolated 209-residue Kgp pro-domain is a boomerang-shaped all-β protein similar to the RgpB pro-domain...
February 14, 2017: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/28196656/a-cdna-clone-launched-platform-for-high-yield-production-of-inactivated-zika-vaccine
#19
Yujiao Yang, Chao Shan, Jing Zou, Antonio E Muruato, Diniz Nunes Bruno, Barbosa de Almeida Medeiros Daniele, Pedro F C Vasconcelos, Shannan L Rossi, Scott C Weaver, Xuping Xie, Pei-Yong Shi
A purified inactivated vaccine (PIV) using the Zika virus (ZIKV) Puerto Rico strain PRVABC59 showed efficacy in monkeys, and is currently in a phase I clinical trial. High-yield manufacture of this PIV is essential for its development and vaccine access. Here we report an infectious cDNA clone-launched platform to maximize its yield. A single NS1 protein substitution (K265E) was identified to increase ZIKV replication on Vero cells (a cell line approved for vaccine production) for both Cambodian FSS13025 and Puerto Rico PRVABC59 strains...
February 6, 2017: EBioMedicine
https://www.readbyqxmd.com/read/28194136/substance-p-and-calcitonin-gene-related-peptide-key-regulators-of-cutaneous-microbiota-homeostasis
#20
REVIEW
Awa N'Diaye, Andrei Gannesen, Valérie Borrel, Olivier Maillot, Jeremy Enault, Pierre-Jean Racine, Vladimir Plakunov, Sylvie Chevalier, Olivier Lesouhaitier, Marc G J Feuilloley
Neurohormones diffuse in sweat and epidermis leading skin bacterial microflora to be largely exposed to these host factors. Bacteria can sense a multitude of neurohormones, but their role in skin homeostasis was only investigated recently. The first study focused on substance P (SP), a neuropeptide produced in abundance by skin nerve terminals. SP is without effect on the growth of Gram-positive (Bacillus cereus, Staphylococcus aureus, and Staphylococcus epidermidis) and Gram-negative (Pseudomonas fluorescens) bacteria...
2017: Frontiers in Endocrinology
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