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Virulence Regulation

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https://www.readbyqxmd.com/read/28817673/the-plasmid-encoded-ipf-and-klf-fimbriae-display-different-expression-and-varying-roles-in-the-virulence-of-salmonella-enterica-serovar-infantis-in-mouse-vs-avian-hosts
#1
Gili Aviv, Laura Elpers, Svetlana Mikhlin, Helit Cohen, Shaul Vitman Zilber, Guntram A Grassl, Galia Rahav, Michael Hensel, Ohad Gal-Mor
Salmonella enterica serovar Infantis is one of the prevalent Salmonella serovars worldwide. Different emergent clones of S. Infantis were shown to acquire the pESI virulence-resistance megaplasmid affecting its ecology and pathogenicity. Here, we studied two previously uncharacterized pESI-encoded chaperone-usher fimbriae, named Ipf and Klf. While Ipf homologs are rare and were found only in S. enterica subspecies diarizonae and subspecies VII, Klf is related to the known K88-Fae fimbria and klf clusters were identified in seven S...
August 2017: PLoS Pathogens
https://www.readbyqxmd.com/read/28816600/deciphering-the-trna-dependent-lipid-aminoacylation-systems-in-bacteria-novel-components-and-structural-advances
#2
Rachel N Fields, Hervé Roy
tRNA-dependent addition of amino acids to lipids on the outer surface of the bacterial membrane results in decreased effectiveness of antimicrobials such as cationic antimicrobial peptides (CAMPs) that target the membrane, and increased virulence of several pathogenic species. After a brief introduction to CAMPs and the various bacterial resistance mechanisms used to counteract these compounds, this review focuses on recent advances in tRNA-dependent pathways for lipid modification in bacteria. Phenotypes associated with amino acid lipid modifications and regulation of their expression will also be discussed...
August 17, 2017: RNA Biology
https://www.readbyqxmd.com/read/28814976/analysis-of-proteomes-released-from-in-vitro-cultured-eight-clostridium-difficile-pcr-ribotypes-revealed-specific-expression-in-pcr-ribotypes-027-and-176-confirming-their-genetic-relatedness-and-clinical-importance-at-the-proteomic-level
#3
Jiri Dresler, Marcela Krutova, Alena Fucikova, Jana Klimentova, Veronika Hruzova, Miloslava Duracova, Katerina Houdkova, Barbora Salovska, Jana Matejkova, Martin Hubalek, Petr Pajer, Libor Pisa, Otakar Nyc
BACKGROUND: Clostridium difficile is the causative agent of C. difficile infection (CDI) that could be manifested by diarrhea, pseudomembranous colitis or life-threatening toxic megacolon. The spread of certain strains represents a significant economic burden for health-care. The epidemic successful strains are also associated with severe clinical features of CDI. Therefore, a proteomic study has been conducted that comprises proteomes released from in vitro cultured panel of eight different PCR ribotypes (RTs) and employs the combination of shotgun proteomics and label-free quantification (LFQ) approach...
2017: Gut Pathogens
https://www.readbyqxmd.com/read/28814823/relationship-between-the-antifungal-susceptibility-profile-and-the-production-of-virulence-related-hydrolytic-enzymes-in-brazilian-clinical-strains-of-candida-glabrata
#4
Maria Helena Galdino Figueiredo-Carvalho, Lívia de Souza Ramos, Leonardo Silva Barbedo, Jean Carlos Almeida de Oliveira, André Luis Souza Dos Santos, Rodrigo Almeida-Paes, Rosely Maria Zancopé-Oliveira
Candida glabrata is a facultative intracellular opportunistic fungal pathogen in human infections. Several virulence-associated attributes are involved in its pathogenesis, host-pathogen interactions, modulation of host immune defenses, and regulation of antifungal drug resistance. This study evaluated the in vitro antifungal susceptibility profile to five antifungal agents, the production of seven hydrolytic enzymes related to virulence, and the relationship between these phenotypes in 91 clinical strains of C...
2017: Mediators of Inflammation
https://www.readbyqxmd.com/read/28814742/the-candida-albicans-hir-histone-chaperone-regulates-the-yeast-to-hyphae-transition-by-controlling-the-sensitivity-to-morphogenesis-signals
#5
Sabrina Jenull, Michael Tscherner, Megha Gulati, Clarissa J Nobile, Neeraj Chauhan, Karl Kuchler
Morphological plasticity such as the yeast-to-hyphae transition is a key virulence factor of the human fungal pathogen Candida albicans. Hyphal formation is controlled by a multilayer regulatory network composed of environmental sensing, signaling, transcriptional modulators as well as chromatin modifications. Here, we demonstrate a novel role for the replication-independent HIR histone chaperone complex in fungal morphogenesis. HIR operates as a crucial modulator of hyphal development, since genetic ablation of the HIR complex subunit Hir1 decreases sensitivity to morphogenetic stimuli...
August 16, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28814525/structure-guided-functional-annotation-of-the-influenza-a-virus-ns1-protein-reveals-dynamic-evolution-of-the-p85%C3%AE-binding-site-during-circulation-in-humans
#6
Antonio M Lopes, Patricia Domingues, Roland Zell, Benjamin G Hale
Rational characterization of virulence and host-adaptive markers in the multifunctional influenza A virus NS1 protein is hindered by a lack of comprehensive knowledge about NS1-host protein-protein interfaces. Here, we surveyed the impact of amino-acid variation in NS1 at its structurally-defined binding site for host p85β, a regulator of phosphoinositide-3 kinase (PI3K) signaling. Structure-guided alanine-scanning of all viral residues at this interface defined 10 positions contributing to the interaction, with residues 89, 95, 98, 133, 145 and 162 being most important...
August 16, 2017: Journal of Virology
https://www.readbyqxmd.com/read/28809156/the-length-of-poly-c-stretch-in-the-bordetella-pertussis-pfim3-promoter-determines-the-vag-or-vrg-function-of-the-fim3-gene
#7
Nao Otsuka, Nicole Guiso, Valérie Bouchez
Bordetella pertussis, a human pathogenic bacterium, produces either one or two types of serologically distinct fimbriae, Fim2 and Fim3, as virulence factors. The expression of fim2 and fim3 is regulated by the BvgAS two-component system and the length of poly(C) stretches in Pfim promoters. In the Bvg+ phase, B. pertussis virulence-activated genes (vags) are up-regulated and virulence-repressed genes (vrgs) are down-regulated. Previous studies have shown that fim2 is a vag, but there is no consensus on fim3 regulation...
August 15, 2017: Microbiology
https://www.readbyqxmd.com/read/28808205/farnesol-inhibits-development-of-caries-by-augmenting-oxygen-sensitivity-and-suppressing-virulence-associated-gene-expression-instreptococcus-mutans
#8
Li Cao, Zhen-Zhen Zhang, Shuang-Bo Xu, Ming Ma, Xin Wei
Streptococcus mutans is a primary etiological agent of dental caries. Farnesol, as a potential antimicrobial agent, inhibits the development ofS. mutans biofilm. In this study, we hypothesized that farnesol inhibits caries development in vitro and interferes with biofilm formation by regulating virulence-associated gene expression. The inhibitory effects of farnesol to S. mutans biofilms on enamel surfaces were investigated by determining micro-hardness and calcium measurements. Additionally, the morphological changes ofS...
July 13, 2017: Journal of Biomedical Research
https://www.readbyqxmd.com/read/28808155/roca-is-an-accessory-protein-to-the-virulence-regulating-covr-s-two-component-system-in-the-group-a-streptococcus
#9
Ira Jain, Eric W Miller, Jessica L Danger, Kathryn J Pflughoeft, Paul Sumby
Regulating gene expression during infection is critical to the ability of pathogens to circumvent the immune response and cause disease. This is true for the group A Streptococcus (GAS), a pathogen that causes both invasive (e.g. necrotizing fasciitis) and non-invasive (e.g. pharyngitis) diseases. The control of virulence (CovR/S) two-component system has a major role in regulating GAS virulence factor expression. The regulator of cov (RocA) protein, which is a predicted kinase, functions in an undetermined manner through CovR/S to alter gene expression and reduce invasive disease virulence...
August 14, 2017: Infection and Immunity
https://www.readbyqxmd.com/read/28808126/growth-and-stress-induced-pasta-kinase-phosphorylation-in-enterococcus-faecalis
#10
Benjamin D Labbe, Christopher J Kristich
Transmembrane Ser/Thr kinases containing extracellular PASTA domains are ubiquitous among Actinobacteria and Firmicutes. Such PASTA kinases regulate critical processes including antibiotic resistance, cell division, toxin production, virulence, and are essential for viability in certain organisms. Based on in vitro studies with purified extra- and intracellular fragments of PASTA kinases, a model for signaling has been proposed, in which the extracellular PASTA domains bind as-yet-undefined ligands - typically thought to be peptidoglycan, or fragments thereof - to drive kinase dimerization, which leads to enhanced kinase autophosphorylation and enhanced phosphorylation of substrates...
August 14, 2017: Journal of Bacteriology
https://www.readbyqxmd.com/read/28807302/targeted-overexpression-of-cyclic-amp-dependent-protein-kinase-subunit-in-toxoplasma-gondii-promotes-replication-and-virulence-in-host-cells
#11
Hongchao Sun, Suhua Wang, Xianfeng Zhao, Chaoqun Yao, Haohan Zhuang, Yechuan Huang, Xueqiu Chen, Yi Yang, Aifang Du
Toxoplasma gondii (T. gondii) is one of the most common parasite that can infect almost any warm-blooded animals including humans. The cyclic nucleotide-dependent protein kinase (PKA) regulates a spectrum of intracellular signal pathways in many organisms. Protein kinase catalytic subunit (PKAC) is the core of the whole protein, and plays an important role in the life cycle of T.gondii. Here, T.gondii PKAC (TgPKAC) overexpression strain (TgPKAC-OE) was constructed. The growth of the TgPKAC-OE, RH△Ku80, and TgPKAC inhibition strains (TgPKAC-H89) were analysed by SYBR-green real-time PCR, and the ultrastructure was observed by transmission electron microscopy...
August 30, 2017: Veterinary Parasitology
https://www.readbyqxmd.com/read/28806780/the-arac-negative-regulator-family-modulates-the-activity-of-histone-like-proteins-in-pathogenic-bacteria
#12
Araceli E Santiago, Michael B Yan, Tracy H Hazen, Brooke Sauder, Mario Meza-Segura, David A Rasko, Melissa M Kendall, Fernando Ruiz-Perez, James P Nataro
The AraC Negative Regulators (ANR) comprise a large family of virulence regulators distributed among diverse clinically important Gram-negative pathogens, including Vibrio spp., Salmonella spp., Shigella spp., Yersinia spp., Citrobacter spp., and pathogenic E. coli strains. We have previously reported broad effects of the ANR members on regulators of the AraC/XylS family. Here, we interrogate possible broader effects of the ANR members on the bacterial transcriptome. Our studies focused on Aar (AggR-activated regulator), an ANR family archetype in enteroaggregative E...
August 14, 2017: PLoS Pathogens
https://www.readbyqxmd.com/read/28806733/the-interaction-between-endogenous-30s-ribosomal-subunit-protein-s11-and-cucumber-mosaic-virus-ls2b-protein-affects-viral-replication-infection-and-gene-silencing-suppressor-activity
#13
Ruilin Wang, Zhiyou Du, Zhenqing Bai, Zongsuo Liang
Cucumber mosaic virus (CMV) is a model virus for plant-virus protein interaction and mechanism research because of its wide distribution, high-level of replication and simple genome structure. The 2b protein is a multifunctional protein encoded by CMV that suppresses RNA silencing-based antiviral defense and contributes to CMV virulence in host plants. In this report, 12 host proteins were identified as CMV LS2b binding partners using the yeast two-hybrid screen system from the Arabidopsis thaliana cDNA library...
2017: PloS One
https://www.readbyqxmd.com/read/28806147/phase-variation-of-clostridium-difficile-virulence-factors
#14
Brandon R Anjuwon-Foster, Rita Tamayo
Clostridium difficile is a leading cause of nosocomial infections, causing disease that ranges from mild diarrhea to potentially fatal colitis. A variety of surface proteins, including flagella, enable C. difficile colonization of the intestine. Once in the intestine, toxigenic C. difficile secretes two glucosylating toxins, TcdA and TcdB, which elicit inflammation and diarrheal disease symptoms. Regulation of colonization factors and TcdA and TcdB is an intense area of research in C. difficile biology. A recent publication from our group describes a novel regulatory mechanism that mediates the ON/OFF expression of co-regulated virulence factors of C...
August 14, 2017: Gut Microbes
https://www.readbyqxmd.com/read/28805296/basidiomycete-specific-pscamkl1-encoding-a-camk-like-protein-kinase-is-required-for-full-virulence-of-puccinia-striiformis-f-sp-tritici
#15
Min Jiao, Dan Yu, Chenglong Tan, Jia Guo, Dingyun Lan, Ershang Han, Tuo Qi, Ralf Thomas Voegele, Zhensheng Kang, Jun Guo
Calcium/calmodulin-dependent kinases (CaMKs) are Ser/Thr protein kinases (PKs) that respond to changes in cytosolic free Ca(2+) and play diverse roles in eukaryotes. In fungi, CAMKs are generally classified into four families CAMK1, CAMKL, RAD53, and CAMK-Unique. Among these, CAMKL constitutes the largest family. In some fungal plant pathogens members of the CaMKL family have been shown to be responsible for pathogenesis. However, little is known about their role(s) in rust fungi. In this study, we functionally characterized a novel PK gene, PsCaMKL1, from Puccinia striiformis f...
August 14, 2017: Environmental Microbiology
https://www.readbyqxmd.com/read/28803907/cu-sensing-transcription-factor-mac1-coordinates-with-the-ctr-transporter-family-to-regulate-cu-acquisition-and-virulence-in-aspergillus-fumigatus
#16
Zhendong Cai, Wenlong Du, Qiuqiong Zeng, Nanbiao Long, Chuanchao Dai, Ling Lu
Copper (Cu) is an essential trace element and is regarded as an important virulence factor in fungal pathogens. Previous studies suggest that a putative Cu-sensing transcription factor Mac1 and the Cu transporter Ctr family play important roles during fungal development and virulence. However, how Cu importers of the Ctr family are involved in the Cu acquisition and what is the functional relationship between them have not been fully investigated yet. Here, we demonstrate that the yeast Mac1 homolog in the opportunistic human pathogen Aspergillus fumigatus is required during colony development under low Cu conditions...
August 10, 2017: Fungal Genetics and Biology: FG & B
https://www.readbyqxmd.com/read/28802028/h5n1-ns-genomic-segment-distinctly-governs-the-influenza-virus-infectivity-and-cytokine-induction-in-monocytic-cells
#17
Prem Prasad Lamichhane, Kobporn Boonnak, Don Changsom, Pirom Noisumdaeng, Kantima Sangsiriwut, Sa-Nga Pattanakitsakul, Pilaipan Puthavathana
BACKGROUND: The level of virulence of H5N1 highly pathogenic avian influenza (HPAI) virus was higher than those of the other virus subtypes. It has been suggested that the nonstructural (NS) gene might be a factor contributing to H5N1 HPAI virulence. OBJECTIVES: To determine the efficiency of the NS genomic segment of H5N1 HPAI virus on governing viral infectivity and cytokine induction in monocytic cells compared to other virus strain/subtypes. METHODS: By reverse genetics, five reassortant influenza viruses carrying the NS genomic segment derived from seasonal influenza A(H1N1), 2009 pandemic A(H1N1), A(H3N2) or H5N1 HPAI virus in the backbone of A/Puerto Rico/8/34 H1N1 (PR8) virus were constructed together with the reassorted PR8 virus control, i...
August 8, 2017: Asian Pacific Journal of Allergy and Immunology
https://www.readbyqxmd.com/read/28800764/lrp-a-global-regulator-regulates-the-virulence-of-vibrio-vulnificus
#18
Yu-Chi Ho, Feng-Ru Hung, Chao-Hui Weng, Wei-Ting Li, Tzu-Hung Chuang, Tsung-Lin Liu, Ching-Yuan Lin, Chien-Jung Lo, Chun-Liang Chen, Jen-Wei Chen, Masayuki Hashimoto, Lien-I Hor
BACKGROUND: An attenuated mutant (designated NY303) of Vibrio vulnificus, which causes serious wound infection and septicemia in humans, was isolated fortuitously from a clinical strain YJ016. This mutant was defective in cytotoxicity, migration on soft agar and virulence in the mouse. The purpose of this study was to map the mutation in this attenuated mutant and further explore how the gene thus identified is involved in virulence. METHODS: The whole genome sequence of mutant NY303 determined by next-generation sequencing was compared with that of strain YJ016 to map the mutations...
August 11, 2017: Journal of Biomedical Science
https://www.readbyqxmd.com/read/28800710/synergistic-effect-of-different-plant-cell-wall-degrading-enzymes-is-important-for-virulence-of-fusarium-graminearum
#19
Maria Chiara Paccanaro, Luca Sella, Carla Castiglioni, Francesca Giacomello, Ana Lilia Martinez-Rocha, Renato D'Ovidio, Wilhelm Schäfer, Francesco Favaron
Endo-polygalacturonases (PGs) and xylanases have been shown to play an important role during pathogenesis of some fungal pathogens of dicot plants, whilst their role in monocot pathogens is less defined. Pg1 and xyr1 genes of the wheat pathogen Fusarium graminearum encode the main PG and the major regulator of xylanase production, respectively. Single and double disrupted mutants for these genes were obtained to assess their contribution to fungal infection. Compared to wild-type strain, the ∆pg mutant showed a nearly abolished PG activity, slight reduced virulence on soybean seedlings but no significant difference in disease symptoms on wheat spikes; the ∆xyr mutant was strongly reduced in xylanase activity and moderately reduced in cellulase activity but was as virulent as wild-type on both soybean and wheat plants...
August 11, 2017: Molecular Plant-microbe Interactions: MPMI
https://www.readbyqxmd.com/read/28800640/knockdown-of-the-plasmodium-falciparum-surfin4-1-antigen-leads-to-an-increase-of-its-cognate-transcript
#20
Tatiane Macedo-Silva, Rosana Beatriz Duque Araujo, Kamila Anna Meissner, Wesley Luzetti Fotoran, Márcia Melo Medeiros, Mauro Ferreira de Azevedo, Gerhard Wunderlich
The genome of the malaria parasite Plasmodium falciparum contains the surf gene family which encodes large transmembrane proteins of unknown function. While some surf alleles appear to be expressed in sexual stages, others occur in asexual blood stage forms and may be associated to virulence-associated processes and undergo transcriptional switching. We accessed the transcription of surf genes along multiple invasions by real time PCR. Based on the observation of persistent expression of gene surf4.1, we created a parasite line which expresses a conditionally destabilized SURFIN4...
2017: PloS One
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