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Travis C Korosh, Andrew Dutcher, Brian F Pfleger, Katherine D McMahon
Sidestreams in wastewater treatment plants can serve as concentrated sources of nutrients (i.e., nitrogen and phosphorus) to support the growth of photosynthetic organisms that ultimately serve as feedstock for production of fuels and chemicals. However, other chemical characteristics of these streams may inhibit growth in unanticipated ways. Here, we evaluated the use of liquid recovered from municipal anaerobic digesters via gravity belt filtration as a nutrient source for growing the cyanobacterium Synechococcus sp...
January 2018: MSphere
Andrew Cameron, Cassidy L Klima, Reuben Ha, Robert J Gruninger, Rahat Zaheer, Tim A McAllister
A novel variant of the AAD(3″) class of aminoglycoside-modifying enzymes was discovered in fatal bovine respiratory disease-associated pathogens Pasteurella multocida and Histophilus somni . The aadA31 gene encodes a spectinomycin/streptomycin adenylyltransferase and was located in a variant of the integrative and conjugative element ICE Mh1 , a mobile genetic element transmissible among members of the family Pasteurellaceae . The gene was also detected in Mannheimia haemolytica from a case of porcine pneumonia and in Moraxella bovoculi from a case of keratoconjunctivitis...
January 2018: MSphere
Aric J Schultz, Vern B Carruthers
Egress is a crucial phase of the Toxoplasma gondii intracellular lytic cycle. This is a process that drives inflammation and is strongly associated with the pathogenesis observed during toxoplasmosis. Despite the link between this process and virulence, little is known about egress on a mechanistic or descriptive level. Previously published work has suggested that a phospholipase, lecithin-cholesterol acyltransferase (LCAT), secreted from the parasite's dense granules contributes to parasite growth, virulence, and egress...
January 2018: MSphere
Whittney N Burda, Karen E Brenneman, Amanda Gonzales, Roy Curtiss
The vast majority of live attenuated typhoid vaccines are constructed from the Salmonella enterica serovar Typhi strain Ty2, which is devoid of a functioning alternative sigma factor, RpoS, due to the presence of a frameshift mutation. RpoS is a specialized sigma factor that plays an important role in the general stress response of a number of Gram-negative organisms, including Salmonella . Previous studies have demonstrated that this sigma factor is necessary for survival following exposure to acid, hydrogen peroxide, nutrient-limiting conditions, and starvation...
January 2018: MSphere
Sarah G Whaley, Kelly E Caudle, Lucia Simonicova, Qing Zhang, W Scott Moye-Rowley, P David Rogers
The high prevalence of fluconazole resistance among clinical isolates of Candida glabrata has greatly hampered the utility of fluconazole for the treatment of invasive candidiasis. Fluconazole resistance in this yeast is almost exclusively due to activating mutations in the transcription factor Pdr1, which result in upregulation of the ABC transporter genes CDR1 , PDH1 , and SNQ2 and therefore increased fluconazole efflux. However, the regulation of Pdr1 is poorly understood. In order to identify genes that interact with the Pdr1 transcriptional pathway and influence the susceptibility of C...
January 2018: MSphere
Yongjin Liu, Steven Kyle, Paul D Straight
Competitive interactions between bacteria reveal physiological adaptations that benefit fitness. Bacillus subtilis is a Gram-positive species with several adaptive mechanisms for competition and environmental stress. Biofilm formation, sporulation, and motility are the outcomes of widespread changes in a population of B. subtilis . These changes emerge from complex, regulated pathways for adapting to external stresses, including competition from other species. To identify competition-specific functions, we cultured B...
January 2018: MSphere
Christel Rothe Brinkmann, Jesper Falkesgaard Højen, Thomas Aagaard Rasmussen, Anne Sofie Kjær, Rikke Olesen, Paul W Denton, Lars Østergaard, Zhengyu Ouyang, Mathias Lichterfeld, Xu Yu, Ole Schmeltz Søgaard, Charles Dinarello, Martin Tolstrup
Histone deacetylase inhibitors (HDACi) modulate the transcriptional activity of all cells, including innate and adaptive immune cells. Therefore, we aimed to evaluate immunological effects of treatment with the HDACi panobinostat in HIV-infected patients during a clinical phase IIa latency reversal trial. Using flow cytometry, we investigated changes in T cell activation (CD69, CD38, HLA-DR) and the expression of CD39 and CTLA4 on regulatory T cells (Tregs). Whole-blood stimulations were performed and cytokine responses measured using Luminex...
January 2018: MSphere
Hülya Kaya, Henrik Hasman, Jesper Larsen, Marc Stegger, Thor Bech Johannesen, Rosa Lundbye Allesøe, Camilla Koldbæk Lemvigh, Frank Møller Aarestrup, Ole Lund, Anders Rhod Larsen
Typing of methicillin-resistant Staphylococcus aureus (MRSA) is important in infection control and surveillance. The current nomenclature of MRSA includes the genetic background of the S. aureus strain determined by multilocus sequence typing (MLST) or equivalent methods like spa typing and typing of the mobile genetic element staphylococcal cassette chromosome mec (SCC mec ), which carries the mecA or mecC gene. Whereas MLST and spa typing are relatively simple, typing of SCC mec is less trivial because of its heterogeneity...
January 2018: MSphere
James Duehr, Silviana Lee, Gursewak Singh, Gregory A Foster, David Krysztof, Susan L Stramer, Maria C Bermúdez González, Eva Menichetti, Robert Geretschläger, Christian Gabriel, Viviana Simon, Jean K Lim, Florian Krammer
Recent reports in the scientific literature have suggested that anti-dengue virus (DENV) and anti-West Nile virus (WNV) immunity exacerbates Zika virus (ZIKV) pathogenesis in vitro and in vivo in mouse models. Large populations of immune individuals exist for a related flavivirus (tick-borne encephalitis virus [TBEV]), due to large-scale vaccination campaigns and endemic circulation throughout most of northern Europe and the southern Russian Federation. As a result, the question of whether anti-TBEV immunity can affect Zika virus pathogenesis is a pertinent one...
January 2018: MSphere
Lisa C Lindesmith, Michael L Mallory, Kari Debbink, Eric F Donaldson, Paul D Brewer-Jensen, Excel W Swann, Timothy P Sheahan, Rachel L Graham, Martina Beltramello, Davide Corti, Antonio Lanzavecchia, Ralph S Baric
Extensive antigenic diversity within the GII.4 genotype of human norovirus is a major driver of pandemic emergence and a significant obstacle to development of cross-protective immunity after natural infection and vaccination. However, human and mouse monoclonal antibody studies indicate that, although rare, antibodies to conserved GII.4 blockade epitopes are generated. The mechanisms by which these epitopes evade immune surveillance are uncertain. Here, we developed a new approach for identifying conserved GII...
January 2018: MSphere
Jamie A Meadows, Matthew J Wargo
The common environmental bacterium and opportunistic pathogen Pseudomonas aeruginosa encodes diverse metabolic pathways and associated regulatory networks allowing it to thrive in these different environments. In an effort to understand P. aeruginosa metabolism and detection of host-derived compounds, we previously identified CdhR and GbdR as members of the AraC transcription factor family that regulate catabolism of the quaternary amine compounds carnitine and glycine betaine, respectively. In this study, our goal was to further characterize regulation of carnitine catabolism by the transcription factor CdhR...
January 2018: MSphere
Robert C Shields, Lin Zeng, David J Culp, Robert A Burne
Transposon mutagenesis coupled with next-generation DNA sequencing (Tn-seq) is a powerful tool for discovering regions of the genome that are required for the survival of bacteria in different environments. We adapted this technique to the dental caries pathogen Streptococcus mutans UA159 and identified 11% of the genome as essential, with many genes encoding products required for replication, translation, lipid metabolism, and cell wall biogenesis. Comparison of the essential genome of S. mutans UA159 with those of selected other streptococci for which such information is available revealed several metabolic pathways and genes that are required in S...
January 2018: MSphere
E Kobayashi, M Aga, S Kondo, C Whitehurst, T Yoshizaki, J S Pagano, J Shackelford
Increasing evidence shows that exosomes are key regulators in cancer cell-to-cell communication. Several reports on Epstein-Barr virus (EBV)-related malignancies demonstrate that latent membrane protein 1 (LMP1) secreted by exosomes derived from EBV- or LMP1-positive cells can promote cancer progression and metastasis. However, the mechanism by which LMP1 is loaded into exosomes is still poorly understood. Here, we examined whether the process of LMP1 loading into exosomes is linked to the multifunctional molecule of the ubiquitin system-ubiquitin C-terminal hydrolase-L1 (UCH-L1)...
January 2018: MSphere
M Desroches, G Royer, D Roche, M Mercier-Darty, D Vallenet, C Médigue, K Bastard, C Rodriguez, O Clermont, E Denamur, J-W Decousser
More than a century ago, Theodor Escherich isolated the bacterium that was to become Escherichia coli, one of the most studied organisms. Not long after, the strain began an odyssey and landed in many laboratories across the world. As laboratory culture conditions could be responsible for major changes in bacterial strains, we conducted a genome analysis of isolates of this emblematic strain from different culture collections (England, France, the United States, Germany). Strikingly, many discrepancies between the isolates were observed, as revealed by multilocus sequence typing (MLST), the presence of virulence-associated genes, core genome MLST, and single nucleotide polymorphism/indel analyses...
January 2018: MSphere
Andres Moreira-Soto, Ianei de Oliveira Carneiro, Carlo Fischer, Marie Feldmann, Beate M Kümmerer, Nama Santos Silva, Uilton Góes Santos, Breno Frederico de Carvalho Dominguez Souza, Fernanda de Azevedo Liborio, Mônica Mafra Valença-Montenegro, Plautino de Oliveira Laroque, Fernanda Rosa da Fontoura, Alberto Vinicius Dantas Oliveira, Christian Drosten, Xavier de Lamballerie, Carlos Roberto Franke, Jan Felix Drexler
Chikungunya virus (CHIKV) and Zika virus (ZIKV) emerged in the Americas in 2013. Limited antigenic variability of CHIKV and ZIKV may restrict urban transmission cycles due to population protective immunity. In Africa, sylvatic transmission cycles involving nonhuman primates (NHP) are known for CHIKV and ZIKV, causing cyclic reemergence in humans. To evaluate whether sylvatic cycles can be expected in Latin America, we tested 207 NHP collected between 2012 and 2017 in urban and peri-urban settings in Brazil for infection with ZIKV and CHIKV...
January 2018: MSphere
Lorena O Fernandes-Siqueira, Julianna D Zeidler, Bruna G Sousa, Thiago Ferreira, Andrea T Da Poian
Dengue virus (DENV) is among the most important human arboviruses and is clinically and experimentally associated with lipid metabolism disorders. Using high-resolution respirometry, we analyzed the metabolic switches induced by DENV in a human hepatic cell line. This experimental approach allowed us to determine the contribution of fatty acids, glutamine, glucose, and pyruvate to mitochondrial bioenergetics, shedding light on the mechanisms involved in DENV-induced metabolic alterations. We found that while infection strongly inhibits glutamine oxidation, it increases the cellular capacity of metabolizing glucose; remarkably, though, this substrate, instead being used as an energy source, performs an anaplerotic role in the oxidation of endogenous lipids...
January 2018: MSphere
Yingru Liu, Julianny Perez, Laura A Hammer, Heather C Gallagher, Magdia De Jesus, Nejat K Egilmez, Michael W Russell
It has previously been shown that genital tract infection with Neisseria gonorrhoeae in mice does not induce a state of protective immunity against reinfection but instead suppresses the development of adaptive immune responses against N. gonorrhoeae dependent on transforming growth factor beta (TGF-β) and interleukin 10 (IL-10). Intravaginal administration during gonococcal infection of IL-12 encapsulated in biodegradable microspheres (IL-12/ms) reverses the immunosuppression and promotes the production of gamma interferon (IFN-γ) and of specific antibodies in serum and genital secretions and accelerates clearance of the infection...
January 2018: MSphere
Mi Zhou, Martin Hünerberg, Yanhong Chen, Tim Reuter, Tim A McAllister, Franklin Evans, Alan T Critchley, Le Luo Guan
The use of Tasco (air-dried Ascophyllum nodosum) as a feed supplement for ruminants has been reported to affect rumen fermentation and reduce Escherichia coli O157:H7 shedding in feces, but the mode of action behind this phenomenon is unclear. In this study, the effects of four Tasco levels (0, 1, 3, and 5%) on rumen microbiota and rumen/fecal E. coli O serogroups in rams were investigated. Rumen total bacteria and archaea were linearly reduced (P < 0.001) and protozoa were linearly increased (P < 0...
January 2018: MSphere
Brandon A Rohnke, Shailendra P Singh, Bagmi Pattanaik, Beronda L Montgomery
Carboxysomes are central to the carbon dioxide-concentrating mechanism (CCM) and carbon fixation in cyanobacteria. Although the structure is well understood, roles of environmental cues in the synthesis, positioning, and functional tuning of carboxysomes have not been systematically studied. Fremyella diplosiphon is a model cyanobacterium for assessing impacts of environmental light cues on photosynthetic pigmentation and tuning of photosynthetic efficiency during complementary chromatic acclimation (CCA), which is controlled by the photoreceptor RcaE...
January 2018: MSphere
Romain Guérillot, Anders Gonçalves da Silva, Ian Monk, Stefano Giulieri, Takehiro Tomita, Eloise Alison, Jessica Porter, Sacha Pidot, Wei Gao, Anton Y Peleg, Torsten Seemann, Timothy P Stinear, Benjamin P Howden
Mutations in the beta-subunit of bacterial RNA polymerase (RpoB) cause resistance to rifampin (Rifr), a critical antibiotic for treatment of multidrug-resistant Staphylococcus aureus. In vitro studies have shown that RpoB mutations confer decreased susceptibility to other antibiotics, but the clinical relevance is unknown. Here, by analyzing 7,099 S. aureus genomes, we demonstrate that the most prevalent RpoB mutations promote clinically relevant phenotypic plasticity resulting in the emergence of stable S...
January 2018: MSphere
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