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https://www.readbyqxmd.com/read/28217744/effect-of-tcdr-mutation-on-sporulation-in-the-epidemic-clostridium-difficile-strain-r20291
#1
Brintha P Girinathan, Marc Monot, Daniel Boyle, Kathleen N McAllister, Joseph A Sorg, Bruno Dupuy, Revathi Govind
Clostridium difficile is an important nosocomial pathogen and the leading cause of hospital-acquired diarrhea. Antibiotic use is the primary risk factor for the development of C. difficile-associated disease because it disrupts normally protective gut flora and enables C. difficile to colonize the colon. C. difficile damages host tissue by secreting toxins and disseminates by forming spores. The toxin-encoding genes, tcdA and tcdB, are part of a pathogenicity locus, which also includes the tcdR gene that codes for TcdR, an alternate sigma factor that initiates transcription of tcdA and tcdB genes...
January 2017: MSphere
https://www.readbyqxmd.com/read/28217743/regulation-of-nitrogen-metabolism-by-gata-zinc-finger-transcription-factors-in-yarrowia-lipolytica
#2
Kyle R Pomraning, Erin L Bredeweg, Scott E Baker
Fungi accumulate lipids in a manner dependent on the quantity and quality of the nitrogen source on which they are growing. In the oleaginous yeast Yarrowia lipolytica, growth on a complex source of nitrogen enables rapid growth and limited accumulation of neutral lipids, while growth on a simple nitrogen source promotes lipid accumulation in large lipid droplets. Here we examined the roles of nitrogen catabolite repression and its regulation by GATA zinc finger transcription factors on lipid metabolism in Y...
January 2017: MSphere
https://www.readbyqxmd.com/read/28217742/piericidin-a1-blocks-yersinia-ysc-type-iii-secretion-system-needle-assembly
#3
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/28217741/transcriptome-level-signatures-in-gene-expression-and-gene-expression-variability-during-bacterial-adaptive-evolution
#4
Keesha E Erickson, Peter B Otoupal, Anushree Chatterjee
Antibiotic-resistant bacteria are an increasingly serious public health concern, as strains emerge that demonstrate resistance to almost all available treatments. One factor that contributes to the crisis is the adaptive ability of bacteria, which exhibit remarkable phenotypic and gene expression heterogeneity in order to gain a survival advantage in damaging environments. This high degree of variability in gene expression across biological populations makes it a challenging task to identify key regulators of bacterial adaptation...
January 2017: MSphere
https://www.readbyqxmd.com/read/28194448/divergent-relationships-between-fecal-microbiota-and-metabolome-following-distinct-antibiotic-induced-disruptions
#5
Jocelyn M Choo, Tokuwa Kanno, Nur Masirah Mohd Zain, Lex E X Leong, Guy C J Abell, Julie E Keeble, Kenneth D Bruce, A James Mason, Geraint B Rogers
The intestinal microbiome plays an essential role in regulating many aspects of host physiology, and its disruption through antibiotic exposure has been implicated in the development of a range of serious pathologies. The complex metabolic relationships that exist between members of the intestinal microbiota and the potential redundancy in functional pathways mean that an integrative analysis of changes in both structure and function are needed to understand the impact of antibiotic exposure. We used a combination of next-generation sequencing and nuclear magnetic resonance (NMR) metabolomics to characterize the effects of two clinically important antibiotic treatments, ciprofloxacin and vancomycin-imipenem, on the intestinal microbiomes of female C57BL/6 mice...
January 2017: MSphere
https://www.readbyqxmd.com/read/28168223/effects-of-organic-amendments-on-microbiota-associated-with-the-culex-nigripalpus-mosquito-vector-of-the-saint-louis-encephalitis-and-west-nile-viruses
#6
Dagne Duguma, Michael W Hall, Chelsea T Smartt, Josh D Neufeld
Pollution from nutrients in aquatic habitats has been linked to increases in disease vectors, including mosquitoes and other pestiferous insects. One possibility is that changes in mosquito microbiomes are impacted by nutrient enrichments and that these changes affect various traits, including larval development, susceptibility to larval control agents, and susceptibility of the adult mosquitoes to pathogens. We tested this hypothesis using field mesocosms supplemented with low- and high-organic-nutrient regimens and then sampled microbial communities associated with the naturally colonizing Culex nigripalpus mosquito vector...
January 2017: MSphere
https://www.readbyqxmd.com/read/28168222/tgprelid-a-mitochondrial-protein-linked-to-multidrug-resistance-in-the-parasite-toxoplasma-gondii
#7
Victoria Jeffers, Edwin T Kamau, Ananth R Srinivasan, Jonathan Harper, Preethi Sankaran, Sarah E Post, Joseph M Varberg, William J Sullivan, Jon P Boyle
New drugs to control infection with the protozoan parasite Toxoplasma gondii are needed as current treatments exert toxic side effects on patients. Approaches to develop novel compounds for drug development include screening of compound libraries and targeted inhibition of essential cellular pathways. We identified two distinct compounds that display inhibitory activity against the parasite's replicative stage: F3215-0002, which we previously identified during a compound library screen, and I-BET151, an inhibitor of bromodomains, the "reader" module of acetylated lysines...
January 2017: MSphere
https://www.readbyqxmd.com/read/28168221/global-population-genetic-analysis-of-aspergillus-fumigatus
#8
Eta Ebasi Ashu, Ferry Hagen, Anuradha Chowdhary, Jacques F Meis, Jianping Xu
Aspergillus fumigatus is a ubiquitous opportunistic fungal pathogen capable of causing invasive aspergillosis, a globally distributed disease with a mortality rate of up to 90% in high-risk populations. Effective control and prevention of this disease require a thorough understanding of its epidemiology. However, despite significant efforts, the global molecular epidemiology of A. fumigatus remains poorly understood. In this study, we analyzed 2,026 A. fumigatus isolates from 13 countries in four continents using nine highly polymorphic microsatellite markers...
January 2017: MSphere
https://www.readbyqxmd.com/read/28144629/pho4-is-essential-for-dissemination-of-cryptococcus-neoformans-to-the-host-brain-by-promoting-phosphate-uptake-and-growth-at-alkaline-ph
#9
Sophie Lev, Keren Kaufman-Francis, Desmarini Desmarini, Pierre G Juillard, Cecilia Li, Sebastian A Stifter, Carl G Feng, Tania C Sorrell, Georges E R Grau, Yong-Sun Bahn, Julianne T Djordjevic
Phosphate acquisition by fungi is regulated by the phosphate-sensing and acquisition (PHO) signaling pathway. Cryptococcus neoformans disseminates from the lung to the brain and is the commonest cause of fungal meningitis worldwide. To investigate the contribution of PHO signaling to cryptococcal dissemination, we characterized a transcription factor knockout strain (hlh3Δ/pho4Δ) defective in phosphate acquisition. Despite little similarity with other fungal Pho4 proteins, Hlh3/Pho4 functioned like a typical phosphate-responsive transcription factor in phosphate-deprived cryptococci, accumulating in nuclei and triggering expression of genes involved in phosphate acquisition...
January 2017: MSphere
https://www.readbyqxmd.com/read/28144628/de-novo-generation-of-a-unique-cervid-prion-strain-using-protein-misfolding-cyclic-amplification
#10
Crystal Meyerett-Reid, A Christy Wyckoff, Terry Spraker, Bruce Pulford, Heather Bender, Mark D Zabel
Substantial evidence supports the hypothesis that prions are misfolded, infectious, insoluble, and protease-resistant proteins (PrP(RES)) devoid of instructional nucleic acid that cause transmissible spongiform encephalopathies (TSEs). Protein misfolding cyclic amplification (PMCA) has provided additional evidence that PrPRes acts as a template that can convert the normal cellular prion protein (PrP(C)) present in uninfected normal brain homogenate (NBH) into the infectious misfolded PrP(RES) isoform. Human PrP(C) has been shown to spontaneously convert to a misfolded pathological state causing sporadic Creutzfeldt-Jakob disease (sCJD)...
January 2017: MSphere
https://www.readbyqxmd.com/read/28124028/optimized-crispr-cas9-genome-editing-for-leishmania-and-its-use-to-target-a-multigene-family-induce-chromosomal-translocation-and-study-dna-break-repair-mechanisms
#11
Wen-Wei Zhang, Patrick Lypaczewski, Greg Matlashewski
CRISPR-Cas9-mediated genome editing has recently been adapted for Leishmania spp. parasites, the causative agents of human leishmaniasis. We have optimized this genome-editing tool by selecting for cells with CRISPR-Cas9 activity through cotargeting the miltefosine transporter gene; mutation of this gene leads to miltefosine resistance. This cotargeting strategy integrated into a triple guide RNA (gRNA) expression vector was used to delete all 11 copies of the A2 multigene family; this was not previously possible with the traditional gene-targeting method...
January 2017: MSphere
https://www.readbyqxmd.com/read/28124027/bacterial-lysis-through-interference-with-peptidoglycan-synthesis-increases-biofilm-formation-by-nontypeable-haemophilus-influenzae
#12
Sara Marti, Carmen Puig, Alexandra Merlos, Miguel Viñas, Marien I de Jonge, Josefina Liñares, Carmen Ardanuy, Jeroen D Langereis
Nontypeable Haemophilus influenzae (NTHi) is an opportunistic pathogen that mainly causes otitis media in children and community-acquired pneumonia or exacerbations of chronic obstructive pulmonary disease in adults. A large variety of studies suggest that biofilm formation by NTHi may be an important step in the pathogenesis of this bacterium. However, the underlying mechanisms involved in this process are poorly elucidated. In this study, we used a transposon mutant library to identify bacterial genes involved in biofilm formation...
January 2017: MSphere
https://www.readbyqxmd.com/read/28124026/effects-of-exogenous-yeast-and-bacteria-on-the-microbial-population-dynamics-and-outcomes-of-olive-fermentations
#13
Jose Zaragoza, Zachary Bendiks, Charlotte Tyler, Mary E Kable, Thomas R Williams, Yelizaveta Luchkovska, Elaine Chow, Kyria Boundy-Mills, Maria L Marco
In this study, we examined Sicilian-style green olive fermentations upon the addition of Saccharomyces cerevisiae UCDFST 09-448 and/or Pichia kudriazevii UCDFST09-427 or the lactic acid bacteria (LAB) Lactobacillus plantarum AJ11R and Leuconostoc pseudomesenteroides BGM3R. Olives containing S. cerevisiae UCDFST 09-448, a strain able to hydrolyze pectin, but not P. kudriazevii UCDFST 09-427, a nonpectinolytic strain, exhibited excessive tissue damage within 4 weeks. DNA sequencing of fungal internal transcribed spacer (ITS) regions and comparisons to a yeast-specific ITS sequence database remarkably showed that neither S...
January 2017: MSphere
https://www.readbyqxmd.com/read/28124025/global-assessment-of-the-activity-of-tigecycline-against-multidrug-resistant-gram-negative-pathogens-between-2004-and-2014-as-part-of-the-tigecycline-evaluation-and-surveillance-trial
#14
Anna Giammanco, Cinzia Calà, Teresa Fasciana, Michael J Dowzicky
Multidrug-resistant (MDR) Gram-negative organisms are a burden on the global health care system. The Tigecycline Evaluation and Surveillance Trial (TEST) is an ongoing global study designed to monitor the in vitro activities of tigecycline and a panel of marketed antimicrobials against a range of clinically significant pathogens. In this study, in vitro data are presented for MDR Acinetobacter baumannii, Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca, Enterobacter aerogenes, and Enterobacter cloacae isolates collected from 2004 to 2014...
January 2017: MSphere
https://www.readbyqxmd.com/read/28101536/host-range-restriction-of-insect-specific-flaviviruses-occurs-at-several-levels-of-the-viral-life-cycle
#15
Sandra Junglen, Marvin Korries, Wolfgang Grasse, Janett Wieseler, Anne Kopp, Kyra Hermanns, Moises León-Juárez, Christian Drosten, Beate Mareike Kümmerer
The genus Flavivirus contains emerging arthropod-borne viruses (arboviruses) infecting vertebrates, as well as insect-specific viruses (ISVs) (i.e., viruses whose host range is restricted to insects). ISVs are evolutionary precursors to arboviruses. Knowledge of the nature of the ISV infection block in vertebrates could identify functions necessary for the expansion of the host range toward vertebrates. Mapping of host restrictions by complementation of ISV and arbovirus genome functions could generate knowledge critical to predicting arbovirus emergence...
January 2017: MSphere
https://www.readbyqxmd.com/read/28101535/the-case-for-adopting-the-species-complex-nomenclature-for-the-etiologic-agents-of-cryptococcosis
#16
Kyung J Kwon-Chung, John E Bennett, Brian L Wickes, Wieland Meyer, Christina A Cuomo, Kurt R Wollenburg, Tihana A Bicanic, Elizabeth Castañeda, Yun C Chang, Jianghan Chen, Massimo Cogliati, Françoise Dromer, David Ellis, Scott G Filler, Matthew C Fisher, Thomas S Harrison, Steven M Holland, Shigeru Kohno, James W Kronstad, Marcia Lazera, Stuart M Levitz, Michail S Lionakis, Robin C May, Popchai Ngamskulrongroj, Peter G Pappas, John R Perfect, Volker Rickerts, Tania C Sorrell, Thomas J Walsh, Peter R Williamson, Jianping Xu, Adrian M Zelazny, Arturo Casadevall
Cryptococcosis is a potentially lethal disease of humans/animals caused by Cryptococcus neoformans and Cryptococcus gattii. Distinction between the two species is based on phenotypic and genotypic characteristics. Recently, it was proposed that C. neoformans be divided into two species and C. gattii into five species based on a phylogenetic analysis of 115 isolates. While this proposal adds to the knowledge about the genetic diversity and population structure of cryptococcosis agents, the published genotypes of 2,606 strains have already revealed more genetic diversity than is encompassed by seven species...
January 2017: MSphere
https://www.readbyqxmd.com/read/28101534/pathogenicity-determinants-of-the-human-malaria-parasite-plasmodium-falciparum-have-ancient-origins
#17
Andrew J Brazier, Marion Avril, Maria Bernabeu, Maxwell Benjamin, Joseph D Smith
Plasmodium falciparum, the most deadly of the human malaria parasites, is a member of the Laverania subgenus that also infects African Great Apes. The virulence of P. falciparum is related to cytoadhesion of infected erythrocytes in microvasculature, but the origin of dangerous parasite adhesion traits is poorly understood. To investigate the evolutionary history of the P. falciparum cytoadhesion pathogenicity determinant, we studied adhesion domains from the chimpanzee malaria parasite P. reichenowi. We demonstrate that the P...
January 2017: MSphere
https://www.readbyqxmd.com/read/28070563/gut-microbiome-of-the-canadian-arctic-inuit
#18
Catherine Girard, Nicolas Tromas, Marc Amyot, B Jesse Shapiro
Diet is a major determinant of community composition in the human gut microbiome, and "traditional" diets have been associated with distinct and highly diverse communities, compared to Western diets. However, most traditional diets studied have been those of agrarians and hunter-gatherers consuming fiber-rich diets. In contrast, the Inuit of the Canadian Arctic have been consuming a traditional diet low in carbohydrates and rich in animal fats and protein for thousands of years. We hypothesized that the Inuit diet and lifestyle would be associated with a distinct microbiome...
January 2017: MSphere
https://www.readbyqxmd.com/read/28070562/biological-and-chemical-adaptation-to-endogenous-hydrogen-peroxide-production-in-streptococcus-pneumoniae-d39
#19
John P Lisher, Ho-Ching Tiffany Tsui, Smirla Ramos-Montañez, Kristy L Hentchel, Julia E Martin, Jonathan C Trinidad, Malcolm E Winkler, David P Giedroc
The catalase-negative, facultative anaerobe Streptococcus pneumoniae D39 is naturally resistant to hydrogen peroxide (H2O2) produced endogenously by pyruvate oxidase (SpxB). Here, we investigate the adaptive response to endogenously produced H2O2. We show that lactate oxidase, which converts lactate to pyruvate, positively impacts pyruvate flux through SpxB and that ΔlctO mutants produce significantly lower H2O2. In addition, both the SpxB pathway and a candidate pyruvate dehydrogenase complex (PDHC) pathway contribute to acetyl coenzyme A (acetyl-CoA) production during aerobic growth, and the pyruvate format lyase (PFL) pathway is the major acetyl-CoA pathway during anaerobic growth...
January 2017: MSphere
https://www.readbyqxmd.com/read/28066815/acknowledgment-of-ad-hoc-reviewers
#20
EDITORIAL
Michael J Imperiale
No abstract text is available yet for this article.
November 2016: MSphere
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