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Virulence Regulation

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https://www.readbyqxmd.com/read/28431199/staphylococcus-aureus-nitric-oxide-synthase-sanos-modulates-aerobic-respiratory-metabolism-and-cell-physiology
#1
Austin B Mogen, Ronan K Carroll, Kimberly L James, Genevy Lima, Dona Silva, Jeffrey A Culver, Christopher Petucci, Lindsey N Shaw, Kelly C Rice
Nitric oxide (NO) is generated from arginine and oxygen via NO synthase (NOS). Staphylococcus aureus NOS (saNOS) has previously been shown to affect virulence and resistance to exogenous oxidative stress, yet the exact mechanism is unknown. Herein, we report a previously-undescribed role of saNOS in S. aureus aerobic physiology. Specifically, aerobic S. aureus nos mutant cultures presented with elevated endogenous reactive oxygen species (ROS) and superoxide levels, as well as increased membrane potential, increased respiratory dehydrogenase activity, and slightly elevated oxygen consumption...
April 21, 2017: Molecular Microbiology
https://www.readbyqxmd.com/read/28429797/sirtuins-in-the-phylum-basidiomycota-a-role-in-virulence-in-cryptococcus-neoformans
#2
Samantha D M Arras, Jessica L Chitty, Maha S I Wizrah, Paige E Erpf, Benjamin L Schulz, Milos Tanurdzic, James A Fraser
Virulence of Cryptococcus neoformans is regulated by a range of transcription factors, and is also influenced by the acquisition of adaptive mutations during infection. Beyond the temporal regulation of virulence factor production by transcription factors and these permanent microevolutionary changes, heritable epigenetic modifications such as histone deacetylation may also play a role during infection. Here we describe the first comprehensive analysis of the sirtuin class of NAD+ dependent histone deacetylases in the phylum Basidiomycota, identifying five sirtuins encoded in the C...
April 21, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28427249/crystal-structure-of-the-regulatory-domain-of-aphb-from-vibrio-vulnificus-a-virulence-gene-regulator
#3
Nohra Park, Saemee Song, Garam Choi, Kyung Ku Jang, Inseong Jo, Sang Ho Choi, Nam-Chul Ha
The transcriptional activator AphB has been implicated in acid resistance and pathogenesis in the food borne pathogens Vibrio vulnificus and Vibrio cholerae. To date, the full-length AphB crystal structure of V. cholerae has been determined and characterized by a tetrameric assembly of AphB consisting of a DNA binding domain and a regulatory domain (RD). Although acidic pH and low oxygen tension might be involved in the activation of AphB, it remains unknown which ligand or stimulus activates AphB at the molecular level...
April 20, 2017: Molecules and Cells
https://www.readbyqxmd.com/read/28426789/gre-factors-mediated-control-of-hild-transcription-is-essential-for-the-invasion-of-epithelial-cells-by-salmonella-enterica-serovar-typhimurium
#4
Tania Gaviria-Cantin, Youssef El Mouali, Soazig Le Guyon, Ute Römling, Carlos Balsalobre
The invasion of epithelial cells by Salmonella enterica serovar Typhimurium is a very tightly regulated process. Signaling cascades triggered by different environmental and physiological signals converge to control HilD, an AraC regulator that coordinates the expression of several virulence factors. The expression of hilD is modulated at several steps of the expression process. Here, we report that the invasion of epithelial cells by S. Typhimurium strains lacking the Gre factors, GreA and GreB, is impaired...
April 2017: PLoS Pathogens
https://www.readbyqxmd.com/read/28426760/regulation-of-proteinaceous-effector-expression-in-phytopathogenic-fungi
#5
REVIEW
Kar-Chun Tan, Richard P Oliver
Effectors are molecules used by microbial pathogens to facilitate infection via effector-triggered susceptibility or tissue necrosis in their host. Much research has been focussed on the identification and elucidating the function of fungal effectors during plant pathogenesis. By comparison, knowledge of how phytopathogenic fungi regulate the expression of effector genes has been lagging. Several recent studies have illustrated the role of various transcription factors, chromosome-based control, effector epistasis, and mobilisation of endosomes within the fungal hyphae in regulating effector expression and virulence on the host plant...
April 2017: PLoS Pathogens
https://www.readbyqxmd.com/read/28423169/innate-immune-response-to-lipooligosaccharide-pivotal-regulator-of-the-pathobiology-of-invasive-neisseria-meningitidis-infections
#6
Constance M John, Nancy J Phillips, Daniel C Stein, Gary A Jarvis
Infections due to Neisseria meningitidis afflict more than one million people worldwide annually and cause death or disability in many survivors. The clinical course of invasive infections has been well studied, but our understanding of the cause of differences in patient outcomes has been limited because these are dependent on multiple factors including the response of the host, characteristics of the bacteria and interactions between the host and the bacteria. The meningococcus is a highly inflammatory organism, and the lipooligosaccharide (LOS) on the outer membrane is the most potent inflammatory molecule it expresses due to the interactions of the lipid A moiety of LOS with receptors of the innate immune system...
April 1, 2017: Pathogens and Disease
https://www.readbyqxmd.com/read/28421674/retraction-statement-dynamic-complex-formation-between-hd-gyp-ggdef-and-pilz-domain-proteins-regulates-motility-in-xanthomonas-campestris
#7
(no author information available yet)
The following article from Molecular Microbiology (2012) 86(3), 557-567, 'Dynamic complex formation between HD-GYP, GGDEF and PilZ domain proteins regulates motility in Xanthomonas campestris' by Robert P. Ryan, Yvonne McCarthy, Patrick A. Kiely, Rosemary O'Connor, Chuck S. Farah, Judith P. Armitage and J. Maxwell Dow published online in Wiley Online Library (wileyonlinelibrary.com), has been retracted by agreement between the authors, the journal Editor-in-Chief, John D Helmann, and John Wiley & Sons Ltd. Since publication of the above article, it has been brought to our attention that there are several image duplications across Figures 3, 5 and 6 including duplication with another article in PNAS: 'Cell-cell signal-dependent dynamic interactions between HD-GYP and GGDEF domain proteins mediate virulence in Xanthomonas campestris', by Robert P...
May 2017: Molecular Microbiology
https://www.readbyqxmd.com/read/28421612/prospective-bacterial-quorum-sensing-inhibitors-from-indian-medicinal-plant-extracts
#8
Bipransh Kumar Tiwary, Runu Ghosh, Saurav Moktan, Vivek Kumar Ranjan, Priyankar Dey, Dibakar Choudhury, Somit Dutta, Dipanwita Deb, Abhaya Prasad Das, Ranadhir Chakraborty
As virulence of many pathogenic bacteria is regulated by the phenomenon of quorum sensing (QS), the present study aimed to find the QS-inhibiting (QS-I) property (if any) in sixty-one Indian medicinal plants. The presence of QS-I compound in the leaf-extract was evaluated by its ability to inhibit production of pigment in Chromobacterium violaceum MTCC 2656 (violacein) and Pseudomonas aeruginosa MTCC 2297 (pyocyanin) or swarming of P. aeruginosa MTCC 2297. Extracts of three plants, Astilbe rivularis, Fragaria nubicola and Osbeckia nepalensis have shown a dose- dependent inhibition of violacein production with no negative effect on bacterial growth...
April 19, 2017: Letters in Applied Microbiology
https://www.readbyqxmd.com/read/28421167/iron-and-virulence-in-francisella-tularensis
#9
REVIEW
Girija Ramakrishnan
Francisella tularensis, the causative agent of tularemia, is a Gram-negative bacterium that infects a variety of cell types including macrophages, and propagates with great efficiency in the cytoplasm. Iron, essential for key enzymatic and redox reactions, is among the nutrients required to support this pathogenic lifestyle and the bacterium relies on specialized mechanisms to acquire iron within the host environment. Two distinct pathways for iron acquisition are encoded by the F. tularensis genome- a siderophore-dependent ferric iron uptake system and a ferrous iron transport system...
2017: Frontiers in Cellular and Infection Microbiology
https://www.readbyqxmd.com/read/28421058/antimicrobial-compounds-produced-by-vaginal-lactobacillus-crispatus-are-able-to-strongly-inhibit-candida-albicans-growth-hyphal-formation-and-regulate-virulence-related-gene-expressions
#10
Shuai Wang, Qiangyi Wang, Ence Yang, Ling Yan, Tong Li, Hui Zhuang
The female vaginal environment contains diverse microorganisms, and their interactions play significant roles in health and disease. Lactobacillus species are the predominant vaginal microorganisms in healthy women and relevant as a barrier to defense against pathogens, including Candida albicans. The yeast-to-hyphae transition is believed to be a determinant of C. albicans pathogenesis. In this study, we investigated the effects of vaginal isolates of L. crispatus (seven strains), L. gasseri (six strains), and L...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28420736/deciphering-the-regulatory-network-between-the-srebp-pathway-and-protein-secretion-in-neurospora-crassa
#11
Lina Qin, Vincent W Wu, N Louise Glass
Sterol regulatory element binding proteins (SREBPs) are conserved from yeast to mammalian cells and function in the regulation of sterol homeostasis. In fungi, the SREBP pathway has been implicated in the adaptation to hypoxia and in virulence. In Neurospora crassa and Trichoderma reesei, the SREBP pathway also negatively regulates protein secretion under lignocellulolytic conditions. Here we utilized global transcriptional profiling combined with genetic and physiological analyses to address the regulatory link between the SREBP pathway and protein secretion in N...
April 18, 2017: MBio
https://www.readbyqxmd.com/read/28418930/the-innate-immunity-of-guinea-pigs-against-highly-pathogenic-avian-influenza-virus-infection
#12
Kun Zhang, Wei Wei Xu, Zhaowei Zhang, Jing Liu, Jing Li, Lijuan Sun, Weiyang Sun, Peirong Jiao, Xiaoyu Sang, Zhiguang Ren, Zhijun Yu, Yuanguo Li, Na Feng, Tiecheng Wang, Hualei Wang, Songtao Yang, Yongkun Zhao, Xuemei Zhang, Peter R Wilker, WenJun Liu, Ming Liao, Hualan Chen, Yuwei Gao, Xianzhu Xia
H5N1 avian influenza viruses are a major pandemic concern. In contrast to the highly virulent phenotype of H5N1 in humans and many animal models, guinea pigs do not typically display signs of severe disease in response to H5N1 virus infection. Here, proteomic and transcriptional profiling were applied to identify host factors that account for the observed attenuation of A/Tiger/Harbin/01/2002 (H5N1) virulence in guinea pigs. RIG-I and numerous interferon stimulated genes were among host proteins with altered expression in guinea pig lungs during H5N1 infection...
March 23, 2017: Oncotarget
https://www.readbyqxmd.com/read/28416708/phou-allows-rapid-adaptation-to-high-phosphate-concentrations-by-modulating-pstscab-transport-rate-in-sinorhizobium-meliloti
#13
George C diCenzo, Harsh Sharthiya, Anish Nanda, Maryam Zamani, Turlough M Finan
Maintenance of cellular phosphate homeostasis is essential for cellular life. The PhoU protein has emerged as a key regulator of this process in bacteria and it is suggested to modulate phosphate import by PstSCAB and control activation of the phosphate limitation response by the PhoR-PhoB two-component system. However, a proper understanding of PhoU has remained elusive due to numerous complications of mutating phoU, including loss of viability and genetic instability of the mutants. Here, we developed two sets of strains of Sinorhizobium meliloti that overcame these limitations and allowed for a more detailed and comprehensive analysis of the biological and molecular activities of PhoU...
April 17, 2017: Journal of Bacteriology
https://www.readbyqxmd.com/read/28415444/formulation-of-thermoreversible-gel-of-cranberry-juice-concentrate-evaluation-biocompatibility-studies-and-its-antimicrobial-activity-against-periodontal-pathogens
#14
Rajeshwari H R, Dinesh Dhamecha, Satveer Jagwani, Dhanashree Patil, Satisha Hegde, Raksha Potdar, Renuka Metgud, Sunil Jalalpure, Subarna Roy, Kiran Jadhav, Neeraj Kumar Tiwari, Sravani Koduru, Shweta Hugar, Suneel Dodamani
The present work aims to investigate the efficacy of thermoreversible gel of cranberry juice concentrate (CJC) as local drug delivery for the treatment of periodontitis. CJC was initially tested for its antimicrobial activities like MIC, MBC, antiadhesion, antibiofilm and time kill assay against the panel of organisms (S. mutans (SM), E. faecalis (EF), A. actinomycetemcomitans (AA), P. gingivalis (PG), T. forsythia (TF)) responsible for periapical and periodontal infections. Antimicrobial activity of CJC showed MIC value of 50mg/ml and MBC value of 100mg/ml with desirable antiadhesion (83-90%) and antibiofilm activity (70-85%)...
June 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
https://www.readbyqxmd.com/read/28412202/the-immunosuppressive-effects-of-a-novel-recombinant-lipq-rv2485c-protein-of-mycobacterium-tuberculosis-on-human-macrophage-cell-lines
#15
Anjani Kumar, Manisha, Gurkamaljit Kaur Sangha, Anju Shrivastava, Jagdeep Kaur
Mycobacterium tuberculosis (MTB), an intracellular pathogen, still represents a major global health challenge. A number of mycobacterial macromolecules have been shown to target biological processes within host macrophages; however, the exact mechanism for the majority of these host pathogen interactions is still poorly understood. Moreover, the lipid metabolic pathway is one of the most important physiologic pathways that plays a vital role in the survival and infection of Mycobacterium tuberculosis. In present study, we investigated the effect of rLipQ from Mycobacterium tuberculosis H37Rv on macrophage functions in vitro...
April 12, 2017: Microbial Pathogenesis
https://www.readbyqxmd.com/read/28411220/the-global-transcription-factor-lrp-is-both-essential-for-and-inhibitory-to-xenorhabdus-nematophila-insecticidal-activity
#16
Ángel M Casanova-Torres, Upasana Shokal, Neta Morag, Ioannis Eleftherianos, Heidi Goodrich-Blair
In the entomopathogenic bacterium Xenorhabdus nematophila, cell-to-cell variation in the abundance of the Lrp transcription factor leads to virulence modulation: low Lrp levels are associated with a virulent phenotype and suppression of antimicrobial peptides (AMPs) in Manduca sexta insects, while cells that lack lrp or express high Lrp levels are virulence attenuated and elicit AMP expression. To better understand the basis of these phenotypes we examined X. nematophila expressing fixed Lrp levels. Unlike the lrp null mutant, the high-lrp strain is fully virulent in Drosophila melanogaster suggesting that these two strains have distinct underlying causes of virulence attenuation in M...
April 14, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28410507/high-level-of-il-10-expression-in-the-blood-of-animal-models-possibly-relates-to-resistance-against-leptospirosis
#17
Mariko Matsui, Louise Roche, Marie-Estelle Soupé-Gilbert, Milena Hasan, Didier Monchy, Cyrille Goarant
Leptospirosis is a severe zoonosis which immunopathogenesis is poorly understood. We evaluated correlation between acute form of the disease and the ratio of the anti-inflammatory cytokine IL-10 to the pro-inflammatory TNF-α and IL-1β expression during the early phase of infection comparing resistant mice and susceptible hamsters infected with two different species of virulent Leptospira. The IL-10/TNF-α and IL-10/IL-1β expression ratios were higher in mouse compared to hamster independently of the Leptospira strain, suggesting a preponderant role of the host response and notably these cytokines in the clinical expression and survival to leptospirosis...
April 11, 2017: Cytokine
https://www.readbyqxmd.com/read/28408162/nuclear-protein-hmgn2-attenuates-pyocyanin-induced-oxidative-stress-via-nrf2-signaling-and-inhibits-pseudomonas-aeruginosa-internalization-in-a549-cells
#18
Keyun Liu, Xinyuan Wang, Kaihui Sha, Fumei Zhang, Feng Xiong, Xiaoying Wang, Junli Chen, Jingyu Li, Leonid P Churilov, Shanze Chen, Yi Wang, Ning Huang
Pyocyanin (PCN, 1-hydroxy-5-methyl-phenazine) is one of the most essential virulence factors of Pseudomonas aeruginosa (PA) to cause various cytotoxic effects in long-term lung infectious diseases, however the early effect of this bacterial toxin during PA infection and subsequent autonomous immune response in host cells have not been fully understood yet. Our results display that early onset of PCN stimulates Pseudomonas aeruginosa PAO1 adhesion and invasion in A549 cells via ROS production. Non-histone nuclear protein HMGN2 is found to be involved in the regulation of PCN-induced oxidative stress by promoting intracellular ROS clearance...
April 10, 2017: Free Radical Biology & Medicine
https://www.readbyqxmd.com/read/28406615/redox-sensitive-marr-homologue-bifr-from-burkholderia-thailandensis-regulates-biofilm-formation
#19
Ashish Gupta, Stanley M Fuentes, Anne Grove
Biofilm formation by pathogenic Burkholderia species is a serious complication as it renders the bacteria resistant to antibiotics and host defenses. Using B. thailandensis, we report here a novel redox-sensitive member of the multiple antibiotic resistance regulator (MarR) protein family, BifR, which represses biofilm formation. BifR is encoded as part of the emrB-bifR operon; emrB-bifR is divergent to ecsC, which encodes a putative LasA protease. In Pseudomonas aeruginosa, LasA has been implicated in virulence by contributing to cleavage of elastase...
April 21, 2017: Biochemistry
https://www.readbyqxmd.com/read/28406453/sequence-polymorphism-and-intrinsic-structural-disorder-as-related-to-pathobiological-performance-of-the-helicobacter-pylori-caga-oncoprotein
#20
REVIEW
Hiroko Nishikawa, Masanori Hatakeyama
CagA, an oncogenic virulence factor produced by Helicobacter pylori, is causally associated with the development of gastrointestinal diseases such as chronic gastritis, peptic ulcers, and gastric cancer. Upon delivery into gastric epithelial cells via bacterial type IV secretion, CagA interacts with a number of host proteins through the intrinsically disordered C-terminal tail, which contains two repeatable protein-binding motifs, the Glu-Pro-Ile-Tyr-Ala (EPIYA) motif and the CagA multimerization (CM) motif...
April 13, 2017: Toxins
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