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Virulence Regulation

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https://www.readbyqxmd.com/read/28637194/high-iron-supply-inhibits-the-synthesis-of-the-genotoxin-colibactin-by-pathogenic-escherichia-coli-through-a-non-canonical-fur-ryhb-mediated-pathway
#1
Sophie Tronnet, Christophe Garcie, Alexander O Brachmann, Jörn Piel, Eric Oswald, Patricia Martin
The genotoxin colibactin is a secondary metabolite produced by a variety of pathogenic Enterobacteria, and is associated with colon cancer development and acute systemic infections. The colibactin biosynthesis requires the enzymatic activity of the phosphopantetheinyl transferase ClbA. We recently evidenced that two master regulators of bacterial iron homeostasis, i.e. the ferric uptake regulator (Fur) and the small regulatory non-coding RNA RyhB, were involved in the regulation of the clbA transcription and of the colibactin production...
June 20, 2017: Pathogens and Disease
https://www.readbyqxmd.com/read/28635589/regulation-of-escherichia-coli-pathogenesis-by-alternative-sigma-factor-n
#2
James T Riordan, Avishek Mitra
σ(N) (also σ(54)) is an alternative sigma factor subunit of the RNA polymerase complex that regulates the expression of genes from many different ontological groups. It is broadly conserved in the Eubacteria with major roles in nitrogen metabolism, membrane biogenesis, and motility. σ(N) is encoded as the first gene of a five-gene operon including rpoN (σ(N)), ptsN, hpf, rapZ, and npr that has been genetically retained among species of Escherichia, Shigella, and Salmonella. In an increasing number of bacteria, σ(N) has been implicated in the control of genes essential to pathogenic behavior, including those involved in adherence, secretion, immune subversion, biofilm formation, toxin production, and resistance to both antimicrobials and biological stressors...
June 2017: EcoSal Plus
https://www.readbyqxmd.com/read/28632016/the-bacteroides-fragilis-pathogenicity-island-links-virulence-and-strain-competition
#3
Benjamin W Casterline, Aaron L Hecht, Vivian M Choi, Juliane Bubeck Wardenburg
The mature microbiome is a stable ecosystem that resists perturbation despite constant host exposure to exogenous microbes. However, the microbial mechanisms determining microbiome development and composition are poorly understood. We recently demonstrated that a non-toxigenic B. fragilis (NTBF) strain restricts enteric colonization by an enterotoxigenic (ETBF) strain dependent on a type VI secretion system (T6SS). We show here that a second enterotoxigenic strain is competent to colonize, dependent on the Bacteroides fragilis pathogenicity island (BFPAI)...
February 23, 2017: Gut Microbes
https://www.readbyqxmd.com/read/28631437/control-of-virulence-gene-transcription-by-indirect-readout-in-vibrio-cholerae-and-salmonella-enterica-serovar-typhimurium
#4
Charles J Dorman, Matthew J Dorman
Indirect readout mechanisms of transcription control rely on the recognition of DNA shape by transcription factors (TFs). TFs may also employ a direct readout mechanism that involves the reading of the base sequence in the DNA major groove at the binding site. TFs with winged helix-turn-helix (wHTH) motifs use an alpha helix to read the base sequence in the major groove while inserting a beta sheet 'wing' into the adjacent minor groove. Such wHTH proteins are important regulators of virulence gene transcription in many pathogens; they also control housekeeping genes...
June 19, 2017: Environmental Microbiology
https://www.readbyqxmd.com/read/28631399/into-the-storm-chasing-the-opportunistic-pathogen-staphylococcus-aureus-from-skin-colonisation-to-life-threatening-infections
#5
James P O'Gara
Colonisation of the human skin by Staphylococcus aureus is a precursor for a variety of infections ranging from boils to sepsis and pneumonia. The rapid emergence of methicillin resistant S. aureus (MRSA) following the clinical introduction of this antimicrobial drug and reports of resistance to all currently used anti-staphylococcal drugs has added to its formidable reputation. S. aureus survival on the skin and in vivo virulence is underpinned by a remarkable environmental adaptability, made possible by highly orchestrated regulation of gene expression and a capacity to undertake genome remodelling...
June 19, 2017: Environmental Microbiology
https://www.readbyqxmd.com/read/28630128/identification-of-a-d-arabinose-5-phosphate-isomerase-in-the-gram-positive-clostridium-tetani
#6
David L Cech, Katherine Markin, Ronald W Woodard
d-Arabinose-5-phosphate isomerases (APIs) catalyze the interconversion of d-ribulose-5-phosphate and d-arabinose-5-phosphate. Various Gram-negative bacteria, such as the uropathogenic E. coli strain CFT073, contain multiple API paralogs (KdsD, GutQ, KpsF and c3406) that have been assigned various cellular functions. The d-arabinose-5-phosphate formed by these enzymes seems to play important roles in the biosynthesis of lipopolysaccharide and group 2 K-antigen capsules, as well as in the regulation of the cellular d-glucitol uptake and uropathogenic infectivity/virulence...
June 19, 2017: Journal of Bacteriology
https://www.readbyqxmd.com/read/28628666/the-effector-avrrxo1-phosphorylates-nad-in-planta
#7
Teja Shidore, Corey D Broeckling, Jay S Kirkwood, John J Long, Jiamin Miao, Bingyu Zhao, Jan E Leach, Lindsay R Triplett
Gram-negative bacterial pathogens of plants and animals employ type III secreted effectors to suppress innate immunity. Most characterized effectors work through modification of host proteins or transcriptional regulators, although a few are known to modify small molecule targets. The Xanthomonas type III secreted avirulence factor AvrRxo1 is a structural homolog of the zeta toxin family of sugar-nucleotide kinases that suppresses bacterial growth. AvrRxo1 was recently reported to phosphorylate the central metabolite and signaling molecule NAD in vitro, suggesting that the effector might enhance bacterial virulence on plants through manipulation of primary metabolic pathways...
June 19, 2017: PLoS Pathogens
https://www.readbyqxmd.com/read/28628655/moend3-regulates-appressorium-formation-and-virulence-through-mediating-endocytosis-in-rice-blast-fungus-magnaporthe-oryzae
#8
Xiao Li, Chuyun Gao, Lianwei Li, Muxing Liu, Ziyi Yin, Haifeng Zhang, Xiaobo Zheng, Ping Wang, Zhengguang Zhang
Eukaryotic cells respond to environmental stimuli when cell surface receptors are bound by environmental ligands. The binding initiates a signal transduction cascade that results in the appropriate intracellular responses. Studies have shown that endocytosis is critical for receptor internalization and signaling activation. In the rice blast fungus Magnaporthe oryzae, a non-canonical G-protein coupled receptor, Pth11, and membrane sensors MoMsb2 and MoSho1 are thought to function upstream of G-protein/cAMP signaling and the Pmk1 MAPK pathway to regulate appressorium formation and pathogenesis...
June 19, 2017: PLoS Pathogens
https://www.readbyqxmd.com/read/28627357/the-heat-shock-protein-90-of-toxoplasma-gondii-is-essential-for-invasion-of-host-cells-and-tachyzoite-growth
#9
Hongchao Sun, Xunhui Zhuo, Xianfeng Zhao, Yi Yang, Xueqiu Chen, Chaoqun Yao, Aifang Du
Toxoplasma gondii is an obligate intracellular apicomplexan parasite that infects almost all warm-blooded vertebrates. Heat shock proteins (HSP) regulate key signal transduction events in many organisms, and heat shock protein 90 (Hsp90) plays an important role in growth, development, and virulence in several parasitic protozoa. Here, we discovered increased transcription of the Hsp90 gene under conditions for bradyzoite differentiation, i.e. alkaline and heat shock conditions in vitro, suggesting that Hsp90 may be connected with bradyzoite development in T...
2017: Parasite: Journal de la Société Française de Parasitologie
https://www.readbyqxmd.com/read/28626452/proteomic-differences-between-developmental-stages-of-toxoplasma-gondii-revealed-by-itraq-based-quantitative-proteomics
#10
Ze-Xiang Wang, Chun-Xue Zhou, Hany M Elsheikha, Shuai He, Dong-Hui Zhou, Xing-Quan Zhu
Toxoplasma gondii has a complex two-host life-cycle between intermediate host and definitive host. Understanding proteomic variations across the life-cycle stages of T. gondii may improve the understanding of molecular adaption mechanism of T. gondii across life-cycle stages, and should have implications for the development of new treatment and prevention interventions against T. gondii infection. Here, we utilized LC-MS/MS coupled with iTRAQ labeling technology to identify differentially expressed proteins (DEPs) specific to tachyzoite (T), bradyzoites-containing cyst (C) and sporulated oocyst (O) stages of the cyst-forming T...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28625543/characterization-of-vibrio-cholerae-o1-strains-that-trace-the-origin-of-haitian-like-genetic-traits
#11
Priyanka Ghosh, Dhirendra Kumar, Goutam Chowdhury, Puneeta Singh, Prosenjit Samanta, Shanta Dutta, T Ramamurthy, N C Sharma, Preety Sinha, Yogendra Prasad, Sumio Shinoda, Asish K Mukhopadhyay
Vibrio cholerae O1 is the etiological agent of the severe diarrheal disease cholera. The bacterium has recently been causing outbreaks in Haiti with catastrophic effects. Numerous mutations have been reported in V. cholerae O1 strains associated with the Haitian outbreak. These mutations encompass among other the genes encoding virulence factors such as the pilin subunit of the toxin-co-regulated pilus (tcpA), cholera toxin B subunit (ctxB), repeat in toxins (rtxA), and other genes such as the quinolone resistance-determining region (QRDR) of gyrase A (gyrA), rstB of RS element along with the alteration in the number of repeat sequences at the promoter region of ctxAB...
June 15, 2017: Infection, Genetics and Evolution
https://www.readbyqxmd.com/read/28623321/dysbiosis-in-chronic-periodontitis-key-microbial-players-and-interactions-with-the-human-host
#12
Zhi-Luo Deng, Szymon P Szafrański, Michael Jarek, Sabin Bhuju, Irene Wagner-Döbler
Periodontitis is an extremely prevalent disease worldwide and is driven by complex dysbiotic microbiota. Here we analyzed the transcriptional activity of the periodontal pocket microbiota from all domains of life as well as the human host in health and chronic periodontitis. Bacteria showed strong enrichment of 18 KEGG functional modules in chronic periodontitis, including bacterial chemotaxis, flagellar assembly, type III secretion system, type III CRISPR-Cas system, and two component system proteins. Upregulation of these functions was driven by the red-complex pathogens and candidate pathogens, e...
June 16, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28622865/pa-x-protein-decreases-replication-and-pathogenicity-of-swine-influenza-virus-in-cultured-cells-and-mouse-models
#13
Xiao-Qian Gong, Ying-Feng Sun, Bao-Yang Ruan, Xiao-Min Liu, Qi Wang, Hai-Ming Yang, Shuai-Yong Wang, Peng Zhang, Xiu-Hui Wang, Tong-Ling Shan, Wu Tong, Yan-Jun Zhou, Guo-Xin Li, Hao Zheng, Guang-Zhi Tong, Hai Yu
Swine influenza viruses have been circulating in pigs throughout world and might be potential threats to human health. PA-X protein is a newly discovered protein produced from the PA gene by ribosomal frameshifting and the effects of PA-X on the 1918 H1N1, the pandemic 2009 H1N1, the highly pathogenic avian H5N1 and the avian H9N2 influenza viruses have been reported. However, the role of PA-X in the pathogenesis of swine influenza virus is still unknown. In this study, we rescued the H1N1 wild-type (WT) classical swine influenza virus (A/Swine/Guangdong/1/2011 (H1N1)) and H1N1 PA-X deficient virus containing mutations at the frameshift motif, and compared their replication properties and pathogenicity of swine influenza virus in vitro and in vivo...
June 2017: Veterinary Microbiology
https://www.readbyqxmd.com/read/28622438/gbf1-differentially-regulates-cat2-and-pad4-transcription-to-promote-pathogen-defense-in-arabidopsis-thaliana
#14
Mrunmay Kumar Giri, Nidhi Singh, Zeeshan Zahoor Banday, Vijayata Singh, Hathi Ram, Deepjyoti Singh, Sudip Chattopadhyay, Ashis Kumar Nandi
G-BOX BINDING FACTOR 1 (GBF1) influences light-regulated seedling development in Arabidopsis, and inhibits CATALASE 2 (CAT2) expression during senescence. CAT2 functions as a scavenger of hydrogen peroxide. Role of GBF1 in defense response is not known. We report here that GBF1 positively influences defense against virulent and avirulent strains of Pseudomonas syringae. The gbf1 mutants are susceptible, whereas GBF1 over-expresser transgenic plants are resistant to bacterial pathogens. GBF1 negatively regulates pathogen-induced CAT2 expression and thereby positively regulates hypersensitive response...
June 16, 2017: Plant Journal: for Cell and Molecular Biology
https://www.readbyqxmd.com/read/28620360/cytr-homolog-of-pectobacterium-carotovorum-subsp-carotovorum-controls-air-liquid-biofilm-formation-by-regulating-multiple-genes-involved-in-cellulose-production-c-di-gmp-signaling-motility-and-type-iii-secretion-system-in-response-to-nutritional-and-environmental
#15
M M Haque, M M H Oliver, Kamrun Nahar, Mohammad Z Alam, Hisae Hirata, Shinji Tsuyumu
Pectobacterium carotovorum subsp. carotovorum [Pcc (formerly Erwinia carotovora subsp. carotovora)] PC1 causes soft-rot disease in a wide variety of plant species by secreting multiple pathogenicity-related traits. In this study, regulatory mechanism of air-liquid (AL) biofilm formation was studied using a cytR homolog gene deletion mutant (ΔcytR) of Pcc PC1. Compared to the wild type (Pcc PC1), the ΔcytR mutant produced fragile and significantly (P < 0.001) lower amounts of AL biofilm on salt-optimized broth plus 2% glycerol (SOBG), yeast peptone dextrose adenine, and also on King's B at 27°C after 72 h incubation in static condition...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28620033/scissor-sisters-regulation-of-adam10-by-the-tspanc8-tetraspanins
#16
REVIEW
Alexandra L Matthews, Justyna Szyroka, Richard Collier, Peter J Noy, Michael G Tomlinson
A disintegrin and metalloprotease 10 (ADAM10) is a ubiquitously expressed transmembrane protein which is essential for embryonic development through activation of Notch proteins. ADAM10 regulates over 40 other transmembrane proteins and acts as a 'molecular scissor' by removing their extracellular regions. ADAM10 is also a receptor for α-toxin, a major virulence factor of Staphylococcus aureus Owing to the importance of its substrates, ADAM10 is a potential therapeutic target for cancer, neurodegenerative diseases such as Alzheimer's and prion diseases, bacterial infection and inflammatory diseases such as heart attack, stroke and asthma...
June 15, 2017: Biochemical Society Transactions
https://www.readbyqxmd.com/read/28619145/thymol-kills-bacteria-reduces-biofilm-formation-and-protects-mice-against-a-fatal-infection-of-actinobacillus-pleuropneumoniae-strain-l20
#17
Lei Wang, Xueqin Zhao, Chunling Zhu, Xiaojing Xia, Wanhai Qin, Mei Li, Tongzhao Wang, Shijun Chen, Yanzhao Xu, Bolin Hang, Yawei Sun, Jinqing Jiang, Langford Paul Richard, Liancheng Lei, Gaiping Zhang, Jianhe Hu
Actinobacillus pleuropneumoniae is the causative agent of the highly contagious and deadly respiratory infection porcine pleuropneumonia, resulting in serious losses to the pig industry worldwide. Alternative to antibiotics are urgently needed due to the serious increase in antimicrobial resistance. Thymol is a monoterpene phenol and efficiently kills a variety of bacteria. This study found that thymol has strong bactericidal effects on the A. pleuropneumoniae 5b serotype strain, an epidemic strain in China...
May 2017: Veterinary Microbiology
https://www.readbyqxmd.com/read/28617307/erratum-michael-a-picker-et-al-h-ns-its-family-members-and-their-regulation-of-virulence-genes-in-shigella-species-genes-2016-7-112
#18
https://www.readbyqxmd.com/read/28614378/comparative-analysis-of-virus-host-interactions-caused-by-a-virulent-and-an-attenuated-duck-hepatitis-a-virus-genotype-1
#19
Xumin Ou, Sai Mao, Jingyu Cao, Anchun Cheng, Mingshu Wang, Dekang Zhu, Shun Chen, Renyong Jia, Mafeng Liu, Kunfeng Sun, Qiao Yang, Ying Wu, Xiaoyue Chen
Because of their better immunogenicity and the improved protection they afford, live attenuated vaccines derived from serial passaging in an abnormal host are widely used to protect humans or animals from certain pathogens. Here, we used a virulent and a chicken embryo-attenuated duck hepatitis A virus genotype 1 to compare the different regulated immune responses induced by viruses with differing virulence. In this study, the attenuated strains had lower protein expression levels than the virulent strains as identified by immunohistochemistry...
2017: PloS One
https://www.readbyqxmd.com/read/28613253/terpenoids-from-platostoma-rotundifolium-briq-a-j-paton-alter-the-expression-of-quorum-sensing-related-virulence-factors-and-the-formation-of-biofilm-in-pseudomonas-aeruginosa-pao1
#20
Tsiry Rasamiravaka, Jérémie Ngezahayo, Laurent Pottier, Sofia Oliveira Ribeiro, Florence Souard, Léonard Hari, Caroline Stévigny, Mondher El Jaziri, Pierre Duez
Platostoma rotundifolium (Briq.) A. J. Paton aerial parts are widely used in Burundi traditional medicine to treat infectious diseases. In order to investigate their probable antibacterial activities, crude extracts from P. rotundifolium were assessed for their bactericidal and anti-virulence properties against an opportunistic bacterial model, Pseudomonas aeruginosa PAO1. Whereas none of the tested extracts exert bacteriostatic and/or bactericidal proprieties, the ethyl acetate and dichloromethane extracts exhibit anti-virulence properties against Pseudomonas aeruginosa PAO1 characterized by an alteration in quorum sensing gene expression and biofilm formation without affecting bacterial viability...
June 14, 2017: International Journal of Molecular Sciences
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