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https://www.readbyqxmd.com/read/28292986/arginine-is-a-critical-substrate-for-the-pathogenesis-of-pseudomonas-aeruginosa-in-burn-wound-infections
#1
Jake Everett, Keith Turner, Qiuxian Cai, Vernita Gordon, Marvin Whiteley, Kendra Rumbaugh
Environmental conditions affect bacterial behavior and can greatly influence the course of an infection. However, the environmental cues that elicit bacterial responses in specific infection sites are relatively unknown. Pseudomonas aeruginosa is ubiquitous in nature and typically innocuous. However, it is also one of the most prevalent causes of fatal sepsis in burn wound patients. The aim of this study was to determine the impact of environmental factors, specifically the availability of arginine, on the pathogenesis of P...
March 14, 2017: MBio
https://www.readbyqxmd.com/read/28292985/binding-of-candida-albicans-to-human-ceacam1-and-ceacam6-modulates-the-inflammatory-response-of-intestinal-epithelial-cells
#2
Esther Klaile, Mario M Müller, Miriam R Schäfer, Ann-Katrin Clauder, Sabina Feer, Kerstin A Heyl, Magdalena Stock, Tilman E Klassert, Peter F Zipfel, Bernhard B Singer, Hortense Slevogt
Candida albicans colonizes human mucosa, including the gastrointestinal tract, as a commensal. In immunocompromised patients, C. albicans can breach the intestinal epithelial barrier and cause fatal invasive infections. Carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1; CD66a), CEACAM5 (CEA), and CEACAM6 (CD66c) are immunomodulatory receptors expressed on human mucosa and are recruited by bacterial and viral pathogens. Here we show for the first time that a fungal pathogen (i.e., C. albicans) also binds directly to the extracellular domain of human CEACAM1, CEACAM3, CEACAM5, and CEACAM6...
March 14, 2017: MBio
https://www.readbyqxmd.com/read/28292984/plaques-formed-by-mutagenized-viral-populations-have-elevated-coinfection-frequencies
#3
Elizabeth R Aguilera, Andrea K Erickson, Palmy R Jesudhasan, Christopher M Robinson, Julie K Pfeiffer
The plaque assay is a common technique used to measure virus concentrations and is based upon the principle that each plaque represents a single infectious unit. As such, the number of plaques is expected to correlate linearly with the virus dilution plated, and each plaque should be formed by a single founder virus. Here, we examined whether more than one virus can contribute to plaque formation. By using genetic and phenotypic assays with genetically marked polioviruses, we found that multiple parental viruses are present in 5 to 7% of plaques, even at an extremely low multiplicity of infection...
March 14, 2017: MBio
https://www.readbyqxmd.com/read/28292983/origins-of-combination-therapy-for-tuberculosis-lessons-for-future-antimicrobial-development-and-application
#4
REVIEW
Christopher A Kerantzas, William R Jacobs
Tuberculosis is a global health problem that causes the death of approximately 1.5 million people worldwide each year (WHO, p. 1-126, Global Tuberculosis Report, 2015). Treatment of drug-susceptible tuberculosis requires combination antimicrobial therapy with a minimum of four antimicrobial agents applied over the course of 6 months. The first instance of combination antimicrobial therapy applied to tuberculosis was the joint use of streptomycin and para-aminosalicylic acid as documented by the Medical Research Council of the United Kingdom in 1950...
March 14, 2017: MBio
https://www.readbyqxmd.com/read/28292982/antibiotic-capture-by-bacterial-lipocalins-uncovers-an-extracellular-mechanism-of-intrinsic-antibiotic-resistance
#5
Omar M El-Halfawy, Javier Klett, Rebecca J Ingram, Slade A Loutet, Michael E P Murphy, Sonsoles Martín-Santamaría, Miguel A Valvano
The potential for microbes to overcome antibiotics of different classes before they reach bacterial cells is largely unexplored. Here we show that a soluble bacterial lipocalin produced by Burkholderia cenocepacia upon exposure to sublethal antibiotic concentrations increases resistance to diverse antibiotics in vitro and in vivo These phenotypes were recapitulated by heterologous expression in B. cenocepacia of lipocalin genes from Pseudomonas aeruginosa, Mycobacterium tuberculosis, and methicillin-resistant Staphylococcus aureus Purified lipocalin bound different classes of bactericidal antibiotics and contributed to bacterial survival in vivo Experimental and X-ray crystal structure-guided computational studies revealed that lipocalins counteract antibiotic action by capturing antibiotics in the extracellular space...
March 14, 2017: MBio
https://www.readbyqxmd.com/read/28292981/vaginal-heparan-sulfate-linked-to-neutrophil-dysfunction-in-the-acute-inflammatory-response-associated-with-experimental-vulvovaginal-candidiasis
#6
Junko Yano, Mairi C Noverr, Paul L Fidel
Despite acute inflammation by polymorphonuclear neutrophils (PMNs) during vulvovaginal candidiasis (VVC), clearance of Candida fails to occur. The purpose of this study was to uncover the mechanism of vaginal PMN dysfunction. Designs included assessing PMN migration, proinflammatory mediators, and tissue damage (by analysis of the activity of lactate dehydrogenase [LDH]) in mice susceptible (C3H/HeN-C57BL/6) or resistant (CD-1) to chronic VVC (CVVC-S or CVVC-R) and testing morphology-specific Candida albicans strains under conditions of preinduced PMN migration (CVVC-S mice) or PMN depletion (CVVC-R mice)...
March 14, 2017: MBio
https://www.readbyqxmd.com/read/28292980/streptococcus-pneumoniae-transmission-is-blocked-by-type-specific-immunity-in-an-infant-mouse-model
#7
Tonia Zangari, Yang Wang, Jeffrey N Weiser
Epidemiological studies on Streptococcus pneumoniae show that rates of carriage are highest in early childhood and that the major benefit of the pneumococcal conjugate vaccine (PCV) is a reduction in the incidence of nasopharyngeal colonization through decreased transmission within a population. In this study, we sought to understand how anti-S. pneumoniae immunity affects nasal shedding of bacteria, the limiting step in experimental pneumococcal transmission. Using an infant mouse model, we examined the role of immunity (passed from mother to pup) on shedding and within-litter transmission of S...
March 14, 2017: MBio
https://www.readbyqxmd.com/read/28292979/the-food-contaminant-deoxynivalenol-exacerbates-the-genotoxicity-of-gut-microbiota
#8
Delphine Payros, Ulrich Dobrindt, Patricia Martin, Thomas Secher, Ana Paula F L Bracarense, Michèle Boury, Joelle Laffitte, Philippe Pinton, Eric Oswald, Isabelle P Oswald
An increasing number of human beings from developed countries are colonized by Escherichia coli strains producing colibactin, a genotoxin suspected to be associated with the development of colorectal cancers. Deoxynivalenol (DON) is the most prevalent mycotoxin that contaminates staple food-especially cereal products-in Europe and North America. This study investigates the effect of the food contaminant DON on the genotoxicity of the E. coli strains producing colibactin. In vitro, intestinal epithelial cells were coexposed to DON and E...
March 14, 2017: MBio
https://www.readbyqxmd.com/read/28270586/emergent-phototactic-responses-of-cyanobacteria-under-complex-light-regimes
#9
Rosanna Man Wah Chau, Devaki Bhaya, Kerwyn Casey Huang
Environmental cues can stimulate a variety of single-cell responses, as well as collective behaviors that emerge within a bacterial community. These responses require signal integration and transduction, which can occur on a variety of time scales and often involve feedback between processes, for example, between growth and motility. Here, we investigate the dynamics of responses of the phototactic, unicellular cyanobacterium Synechocystis sp. PCC6803 to complex light inputs that simulate the natural environments that cells typically encounter...
March 7, 2017: MBio
https://www.readbyqxmd.com/read/28270585/transcriptome-remodeling-of-acinetobacter-baumannii-during-infection-and-treatment
#10
Meredith S Wright, Michael R Jacobs, Robert A Bonomo, Mark D Adams
Acinetobacter baumannii is an increasingly common multidrug-resistant pathogen in health care settings. Although the genetic basis of antibiotic resistance mechanisms has been extensively studied, much less is known about how genetic variation contributes to other aspects of successful infections. Genetic changes that occur during host infection and treatment have the potential to remodel gene expression patterns related to resistance and pathogenesis. Longitudinal sets of multidrug-resistant A. baumannii isolates from eight patients were analyzed by RNA sequencing (RNA-seq) to identify differentially expressed genes and link them to genetic changes contributing to transcriptional variation at both within-patient and population levels...
March 7, 2017: MBio
https://www.readbyqxmd.com/read/28270584/viruses-in-the-oceanic-basement
#11
Olivia D Nigro, Sean P Jungbluth, Huei-Ting Lin, Chih-Chiang Hsieh, Jaclyn A Miranda, Christopher R Schvarcz, Michael S Rappé, Grieg F Steward
Microbial life has been detected well into the igneous crust of the seafloor (i.e., the oceanic basement), but there have been no reports confirming the presence of viruses in this habitat. To detect and characterize an ocean basement virome, geothermally heated fluid samples (ca. 60 to 65°C) were collected from 117 to 292 m deep into the ocean basement using seafloor observatories installed in two boreholes (Integrated Ocean Drilling Program [IODP] U1362A and U1362B) drilled in the eastern sediment-covered flank of the Juan de Fuca Ridge...
March 7, 2017: MBio
https://www.readbyqxmd.com/read/28270583/a-reverse-genetics-platform-that-spans-the-zika-virus-family-tree
#12
Douglas G Widman, Ellen Young, Boyd L Yount, Kenneth S Plante, Emily N Gallichotte, Derek L Carbaugh, Kayla M Peck, Jessica Plante, Jesica Swanstrom, Mark T Heise, Helen M Lazear, Ralph S Baric
Zika virus (ZIKV), a mosquito-borne flavivirus discovered in 1947, has only recently caused large outbreaks and emerged as a significant human pathogen. In 2015, ZIKV was detected in Brazil, and the resulting epidemic has spread throughout the Western Hemisphere. Severe complications from ZIKV infection include neurological disorders such as Guillain-Barré syndrome in adults and a variety of fetal abnormalities, including microcephaly, blindness, placental insufficiency, and fetal demise. There is an urgent need for tools and reagents to study the pathogenesis of epidemic ZIKV and for testing vaccines and antivirals...
March 7, 2017: MBio
https://www.readbyqxmd.com/read/28270582/bacteria-getting-into-shape-genetic-determinants-of-e-%C3%A2-coli-morphology
#13
Shawn French, Jean-Philippe Côté, Jonathan M Stokes, Ray Truant, Eric D Brown
Perturbation of cellular processes is a prevailing approach to understanding biology. To better understand the complicated biology that defines bacterial shape, a sensitive, high-content platform was developed to detect multiple morphological defect phenotypes using microscopy. We examined morphological phenotypes across the Escherichia coli K-12 deletion (Keio) collection at the mid-exponential growth phase, revealing 111 deletions perturbing shape. Interestingly, 64% of these were uncharacterized mutants, illustrating the complex nature of shape maintenance and regulation in bacteria...
March 7, 2017: MBio
https://www.readbyqxmd.com/read/28270581/reply-to-misclassification-of-pfeh1-and-pfeh2-as-epoxide-hydrolases
#14
Daniel E Goldberg, Natalie J Spillman
No abstract text is available yet for this article.
March 7, 2017: MBio
https://www.readbyqxmd.com/read/28270580/microevolution-of-serial-clinical-isolates-of-cryptococcus-neoformans-var-grubii-and-c-%C3%A2-gattii
#15
Yuan Chen, Rhys A Farrer, Charles Giamberardino, Sharadha Sakthikumar, Alexander Jones, Timothy Yang, Jennifer L Tenor, Omar Wagih, Marelize Van Wyk, Nelesh P Govender, Thomas G Mitchell, Anastasia P Litvintseva, Christina A Cuomo, John R Perfect
The pathogenic species of Cryptococcus are a major cause of mortality owing to severe infections in immunocompromised as well as immunocompetent individuals. Although antifungal treatment is usually effective, many patients relapse after treatment, and in such cases, comparative analyses of the genomes of incident and relapse isolates may reveal evidence of determinative, microevolutionary changes within the host. Here, we analyzed serial isolates cultured from cerebrospinal fluid specimens of 18 South African patients with recurrent cryptococcal meningitis...
March 7, 2017: MBio
https://www.readbyqxmd.com/read/28270579/the-cell-wall-lipid-pdim-contributes-to-phagosomal-escape-and-host-cell-exit-of-mycobacterium-tuberculosis
#16
Jeff Quigley, V Keith Hughitt, Carlos A Velikovsky, Roy A Mariuzza, Najib M El-Sayed, Volker Briken
The cell wall of Mycobacterium tuberculosis is composed of unique lipids that are important for pathogenesis. Indeed, the first-ever genetic screen in M. tuberculosis identified genes involved in the biosynthesis and transport of the cell wall lipid PDIM (phthiocerol dimycocerosates) as crucial for the survival of M. tuberculosis in mice. Here we show evidence for a novel molecular mechanism of the PDIM-mediated virulence in M. tuberculosis We characterized the DNA interaction and the regulon of Rv3167c, a transcriptional repressor that is involved in virulence regulation of M...
March 7, 2017: MBio
https://www.readbyqxmd.com/read/28270578/human-cytomegalovirus-micrornas-mir-us5-1-and-mir-ul112-3p-block-proinflammatory-cytokine-production-in-response-to-nf-%C3%AE%C2%BAb-activating-factors-through-direct-downregulation-of-ikk%C3%AE-and-ikk%C3%AE
#17
Meaghan H Hancock, Lauren M Hook, Jennifer Mitchell, Jay A Nelson
Emerging evidence indicates that human cytomegalovirus (HCMV) manipulates host cell signaling pathways using both proteins and noncoding RNAs. Several studies have shown that HCMV induces NF-κB signaling early in infection, resulting in the induction of antiviral proinflammatory cytokines with a subsequent reduction of these cytokines late in infection. The mechanism for late cytokine reduction is unknown. In this study, we show that HCMV microRNAs (miRNAs) miR-US5-1 and miR-UL112-3p target the IκB kinase (IKK) complex components IKKα and IKKβ to limit production of proinflammatory cytokines in response to interleukin 1β (IL-1β) and tumor necrosis factor alpha (TNF-α)...
March 7, 2017: MBio
https://www.readbyqxmd.com/read/28270577/misclassification-of-pfeh1-and-pfeh2-as-epoxide-hydrolases
#18
LETTER
Michael Arand, Anne Marowsky
No abstract text is available yet for this article.
March 7, 2017: MBio
https://www.readbyqxmd.com/read/28246365/role-of-eosinophils-and-tumor-necrosis-factor-alpha-in-interleukin-25-mediated-protection-from-amebic-colitis
#19
Zannatun Noor, Koji Watanabe, Mayuresh M Abhyankar, Stacey L Burgess, Erica L Buonomo, Carrie A Cowardin, William A Petri
The parasite Entamoeba histolytica is a cause of diarrhea in infants in low-income countries. Previously, it was shown that tumor necrosis factor alpha (TNF-α) production was associated with increased risk of E. histolytica diarrhea in children. Interleukin-25 (IL-25) is a cytokine that is produced by intestinal epithelial cells that has a role in maintenance of gut barrier function and inhibition of TNF-α production. IL-25 expression was decreased in humans and in the mouse model of amebic colitis. Repletion of IL-25 blocked E...
February 28, 2017: MBio
https://www.readbyqxmd.com/read/28246364/elevated-cholesterol-in-the-coxiella-burnetii-intracellular-niche-is-bacteriolytic
#20
Minal Mulye, Dhritiman Samanta, Seth Winfree, Robert A Heinzen, Stacey D Gilk
Coxiella burnetii is an intracellular bacterial pathogen and a significant cause of culture-negative endocarditis in the United States. Upon infection, the nascent Coxiella phagosome fuses with the host endocytic pathway to form a large lysosome-like vacuole called the parasitophorous vacuole (PV). The PV membrane is rich in sterols, and drugs perturbing host cell cholesterol homeostasis inhibit PV formation and bacterial growth. Using cholesterol supplementation of a cholesterol-free cell model system, we found smaller PVs and reduced Coxiella growth as cellular cholesterol concentration increased...
February 28, 2017: MBio
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