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virulence factor

Petra Břehová, Markéta Šmídková, Jan Skácel, Martin Dračínský, Helena Mertlíková-Kaiserová, Monica P Soto Velasquez, Val J Watts, Zlatko Janeba
Bordetella pertussis adenylate cyclase toxin (ACT) and Bacillus anthracis edema factor (EF) are key virulence factors with adenylate cyclase (AC) activity that substantially contribute to the pathogenesis of whooping cough and anthrax, respectively. There is an urgent need to develop potent and selective inhibitors of bacterial ACs with prospects for the development of potential antibacterial therapeutics and to study their molecular interactions with the target enzymes. Novel fluorescent 5-chloroanthraniloyl-substituted acyclic nucleoside phosphonates (Cl-ANT-ANPs) were designed and synthesized in the form of their diphosphates (Cl-ANT-ANPpp) as competitive ACT and EF inhibitors with sub-micromolar potency (IC50 values: 11-622 nm)...
October 24, 2016: ChemMedChem
Thiago Aparecido da Silva, Maria Cristina Roque-Barreira, Arturo Casadevall, Fausto Almeida
Extracellular vesicles (EVs) released by eukaryotes, archaea, and bacteria contain proteins, lipids, polysaccharides, and other molecules. The cargo analysis of EVs shows that they contain virulence factors suggesting a role in the pathogenesis of infection. The proteome, lipidome, RNA content, and carbohydrate composition of EVs from Paracoccidioides brasiliensis and Paracoccidioides lutzii were characterized. However, the effects of P. brasiliensis EVs on the host immune system have not yet been investigated...
October 24, 2016: Scientific Reports
José Peña, Haiyin Chen-Harris, Jonathan E Allen, Mona Hwang, Maher Elsheikh, Shalini Mabery, Helle Bielefeldt-Ohmann, Adam T Zemla, Richard A Bowen, Monica K Borucki
In vivo serial passage of non-pathogenic viruses has been shown to lead to increased viral virulence, and although the precise mechanism(s) are not clear, it is known that both host and viral factors are associated with increased pathogenicity. Under- or overnutrition leads to a decreased or dysregulated immune response and can increase viral mutant spectrum diversity and virulence. The objective of this study was to identify the role of viral mutant spectra dynamics and host immunocompetence in the development of pathogenicity during in vivo passage...
January 2016: Virus Evolution
Rachel Breyta, Doug McKenney, Tarin Tesfaye, Kotaro Ono, Gael Kurath
Surveillance and genetic typing of field isolates of a fish rhabdovirus, infectious hematopoietic necrosis virus (IHNV), has identified four dominant viral genotypes that were involved in serial viral emergence and displacement events in steelhead trout (Oncorhynchus mykiss) in western North America. To investigate drivers of these landscape-scale events, IHNV isolates designated 007, 111, 110, and 139, representing the four relevant genotypes, were compared for virulence and infectivity in controlled laboratory challenge studies in five relevant steelhead trout populations...
January 2016: Virus Evolution
Jacob E Choby, Laura A Mike, Ameya A Mashruwala, Brendan F Dutter, Paul M Dunman, Gary A Sulikowski, Jeffrey M Boyd, Eric P Skaar
The rising problem of antimicrobial resistance in Staphylococcus aureus necessitates the discovery of novel therapeutic targets for small-molecule intervention. A major obstacle of drug discovery is identifying the target of molecules selected from high-throughput phenotypic assays. Here, we show that the toxicity of a small molecule termed '882 is dependent on the constitutive activity of the S. aureus virulence regulator SaeRS, uncovering a link between virulence factor production and energy generation. A series of genetic, physiological, and biochemical analyses reveal that '882 inhibits iron-sulfur (Fe-S) cluster assembly most likely through inhibition of the Suf complex, which synthesizes Fe-S clusters...
October 19, 2016: Cell Chemical Biology
Andrew R Wargo, Robert J Scott, Benjamin Kerr, Gael Kurath
Viral replication and shedding are key components of transmission and fitness, the kinetics of which are heavily dependent on virus, host, and environmental factors. To date, no studies have quantified the shedding kinetics of infectious hematopoietic necrosis virus (IHNV) in rainbow trout (Oncorhynchus mykiss), or how they are associated with replication, making it difficult to ascertain the transmission dynamics of this pathogen of high agricultural and conservation importance. Here, the replication and shedding kinetics of two M genogroup IHNV genotypes were examined in their naturally co-evolved rainbow trout host...
October 19, 2016: Virus Research
Dong Wang, Limei Zhang, Xuezhang Zhou, Yulong He, Changfu Yong, Mingliang Shen, Otto Szenci, Bo Han
Staphylococcus aureus is the leading pathogen involved in bovine mastitis, but knowledge about antimicrobial resistance, virulence factors, and genotypes of Staphylococcus aureus resulting in bovine mastitis in Ningxia, China, is limited. Therefore, antimicrobial susceptibility, virulence gene, and randomly amplified polymorphic DNA (RAPD) analyses of Staph. aureus were carried out. A total of 327 milk samples from cows with clinical and subclinical mastitis in 4 regions of Ningxia were used for the isolation and identification of pathogens according to phenotypic and molecular characteristics...
October 19, 2016: Journal of Dairy Science
Chiung-Wen Hsu, Siou-Cen Li, Nai-Yun Chang, Zeng-Weng Chen, Jiunn-Wang Liao, Ter-Hsin Chen, Jyh-Perng Wang, Jiunn-Horng Lin, Shih-Ling Hsuan
Actinobacillus pleuropneumoniae is a crucial respiratory pathogen that causes fibrinous, hemorrhagic, necrotizing pleuropneumonia in pigs. A. pleuropneumoniae exotoxins (ApxI to IV) are the major virulence factors contributing to A. pleuropneumoniae pathogenesis. Previously, we demonstrated that ApxI induces the expression of proinflammatory cytokines in porcine alveolar macrophages (PAMs) via the mitogen-activated protein kinases (MAPKs) p38 and cJun NH2-terminal kinase (JNK). Nonetheless, the role of nuclear factor (NF)-κB-a transcription factor widely implicated in immune and inflammatory responses-in ApxI-elicited cytokine production has yet to be defined...
November 15, 2016: Veterinary Microbiology
Agata A Cisek, Iwona Dąbrowska, Karolina P Gregorczyk, Zbigniew Wyżewski
African swine fever (ASF) is a highly contagious viral disease of swine with a mortality rate approaching 100 percent. African Swine Fever Virus (ASFV) is a double-stranded DNA virus with a complex molecular structure. Its large genome, encoding multiple virulence factors, allows for efficient replication, which takes place predominantly in the cytoplasm of monocytes and macrophages. Also, ASFV has the ability to interfere with cell signalling pathways, which leads to various modulations in the synthesis profiles of interferon and other cytokines...
October 1, 2016: Annals of Parasitology
Marilucia Santos Ludovico, Luciano Moura Martins, Juares Ednaldo Romero Bianco, Célia Guadalupe Tardelli de Jesus Andrade, Rosabel Falcon, Paulo Pinto Joazeiro, Maria Silvia Viccari Gatti, Tomomasa Yano
Plesiomonas shigelloides isolated from water in Brazil was previously described as a hemorrhagic heat-labile cytotoxic-enterotoxin producer. We purified this toxin from culture supernatants using ion metallic affinity chromatography (IMAC) followed by molecular exclusion chromatography. The pure toxin presented molecular mass of 50kDa and isoelectric point (pI) around 6.9 by 2D electrophoresis. When injected intravenously, the purified cytotoxic-enterotoxin induced also severe spasms followed by sudden death of mice...
October 19, 2016: Brazilian Journal of Infectious Diseases
Fernando Vargas-Romero, Guillermo Mendoza-Hernández, Francisco Suarez-Güemes, Rogelio Hernández-Pando, Mauricio Castañón-Arreola
Mycobacterium bovis is the causative agent of tuberculosis in farms, wildlife and causes sporadic disease in humans. Despite the high similitude in genome sequence between M. bovis strains, some strains like the wild boar 04-303 isolate show a highly virulent phenotype in animal models. Comparative studies will contribute to link protein expression with the virulence phenotype. In vitro, the 04-303 strain was more phagocytized by J774A.1 macrophages in comparison with 444 strain (a cow isolate with the same genotype) and BCG...
October 18, 2016: Microbial Pathogenesis
Shawn I Walsh, Arryn Craney, Floyd E Romesberg
The looming antibiotic crisis has prompted the development of new strategies towards fighting infection. Traditional antibiotics target bacterial processes essential for viability, whereas proposed antivirulence approaches rely on the inhibition of factors that are required only for the initiation and propagation of infection within a host. Although antivirulence compounds have yet to prove their efficacy in the clinic, bacterial signal peptidase I (SPase) represents an attractive target in that SPase inhibitors exhibit broad-spectrum antibiotic activity, but even at sub-MIC doses also impair the secretion of essential virulence factors...
September 21, 2016: Bioorganic & Medicinal Chemistry
A Didier, R Dietrich, E Märtlbauer
The non-hemolytic enterotoxin complex (Nhe) is supposed to be the main virulence factor of B. cereus causing a diarrheal outcome of food poisoning. This tripartite toxin consists of the single components NheA, -B and -C all of them being necessary for maximum toxicity. In the past, research activities aiming to elucidate the mode-of-action of Nhe were mostly focused on the B- and C-component. In this study the generation of novel monoclonal antibodies (mAb) and their thorough characterization enabled the determination of key features for NheA...
2016: PloS One
Philippe Hermand, Annick Vandercammen, Emmanuel Mertens, Emmanuel Di Paolo, Vincent Verlant, Philippe Denoël, Fabrice Godfroid
The use of protein antigens able to protect against the majority of Streptococcus pneumoniae serotypes is envisaged as stand-alone and/or complement to the current capsular polysaccharide-based pneumococcal vaccines. Pneumolysin (Ply) is a key virulence factor that is highly conserved in amino acid sequence across pneumococcal serotypes, and therefore may be considered as a vaccine target. However, native Ply cannot be used in vaccines due to its intrinsic cytolytic activity. In the present work a completely, irreversibly detoxified pneumolysin (dPly) has been generated using an optimized formaldehyde treatment...
October 21, 2016: Human Vaccines & Immunotherapeutics
Ranjith Rajendran, Ali May, Leighann Sherry, Ryan Kean, Craig Williams, Brian L Jones, Karl V Burgess, Jaap Heringa, Sanne Abeln, Bernd W Brandt, Carol A Munro, Gordon Ramage
Candida albicans biofilm formation is an important virulence factor in the pathogenesis of disease, a characteristic which has been shown to be heterogeneous in clinical isolates. Using an unbiased computational approach we investigated the central metabolic pathways driving biofilm heterogeneity. Transcripts from high (HBF) and low (LBF) biofilm forming isolates were analysed by RNA sequencing, with 6312 genes identified to be expressed in these two phenotypes. With a dedicated computational approach we identified and validated a significantly differentially expressed subnetwork of genes associated with these biofilm phenotypes...
October 21, 2016: Scientific Reports
Gang Li, Mengyu Shen, Shuai Le, Yinling Tan, Ming Li, Xia Zhao, Wei Shen, Yuhui Yang, Jing Wang, Hongbin Zhu, Shu Li, Xiancai Rao, Fuquan Hu, Shuguang Lu
As a third-generation sequencing method, single-molecule real-time (SMRT) technology provides long read length, and it is well suited for re-sequencing projects and de novo assembly. In this study, Pseudomonas aeruginosa PA1 was characterized and re-sequenced using SMRT technology. PA1 was also subjected to genomic, comparative, and pan-genomic analyses. The multi-drug resistant strain PA1 possesses a 6,498,072 bp genome and a sequence type of ST-782. The genome of PA1 was also visualized, and the results revealed the details of general genome annotations, virulence factors, regulatory proteins, secretion system proteins, type II toxin-antitoxin pairs, and genomic islands...
October 20, 2016: Bioscience Reports
Ahmed Abdel Megeed, M Ali Hayssam, Mohamed Z M Salem, Mohamed S El-Shikh, Ibrahim Ahmed Talea, Yahya A Alogaibi
Multidrug-resistant (MDR) Acinetobacter baumannii infections are a great public health concern and demand continuous surveillance and antibiotic stewardship. Virulence traits and the pathogenicity of Acinetobacter are less studied compared with the molecular epidemiological and antibiotic resistance profile of this organism. In our present study, we investigated the primary characteristics contributing to the virulence of MDR A. baumannii isolates and compared them with avirulent isolates. A total of 32 well-characterized MDR A...
October 19, 2016: Journal of AOAC International
Shivanand Hegde, Martina Zimmermann, Martina Flöck, Rene Brunthaler, Joachim Spergser, Renate Rosengarten, Rohini Chopra-Dewasthaly
Mycoplasmas are amongst the most successful pathogens of both humans and animals yet the molecular basis of mycoplasma pathogenesis is poorly understood. This is partly due to the lack of classical virulence factors and little similarity to common bacterial pathogenic determinants. Using Mycoplasma agalactiae as a model we initiated research in this direction by screening a transposon mutant library in the natural sheep host using a negative selection method. Having successfully identified putative factors involved in the colonization of local infection and lymphogenic sites, the current study assessed mutants unable to spread systemically in sheep after experimental intramammary infection...
October 20, 2016: Veterinary Research
Ishita Mukherjee, Abhijit Chakraborty, Saikat Chakrabarti
BACKGROUND: An active immune surveillance and a range of barriers to infection allow the host to effectively eliminate microbial pathogens. However, pathogens may use diverse strategies to subdue such host defences. For instance, one such mechanism is the use of leucine-rich repeat (LRR) proteins by pathogens (microbial) to cause infection. In this study, we aimed at identifying novel virulence factor(s) in Leishmania donovani, based on the possibility of lateral gene transfers of bacterial virulence factor(s) to L...
October 21, 2016: Parasites & Vectors
Kuo-Hsun Chiu, Ling-Hui Wang, Tsung-Ting Tsai, Huan-Yao Lei, Pao-Chi Liao
The secreted proteins of bacteria are usually accompanied by virulence factors, which can cause inflammation and damage host cells. Identifying the secretomes arising from the interactions of bacteria and host cells could, therefore, increase understanding of the mechanisms during initial pathogenesis. The present study used a host-pathogen coculture system of Helicobacter pylori and monocytes (THP-1 cells) to investigate the secreted proteins associated with initial H. pylori pathogenesis. The secreted proteins from the conditioned media from H...
October 20, 2016: Journal of Proteome Research
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