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https://www.readbyqxmd.com/read/28526785/effects-of-arginine-on-growth-virulence-gene-expression-and-stress-tolerance-by-streptococcus-mutans
#1
Brinta Chakraborty, Robert A Burne
Streptococcus mutans is a common constituent of oral biofilms and a primary etiologic agent of human dental caries. The bacteria associated with dental caries have a potent ability to produce organic acids from dietary carbohydrates and to grow and metabolize in acidic conditions. In contrast, many commensal bacteria produce ammonia through the arginine deiminase system (ADS), which moderates the pH of oral biofilms. Arginine metabolism by the ADS is a significant deterrent to the initiation and progression of dental caries...
May 19, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28526748/the-sialate-o-acetylesterase-esta-from-gut-bacteroidetes-species-enables-sialidase-mediated-cross-species-foraging-of-9-o-acetylated-sialoglycans
#2
Lloyd S Robinson, Warren G Lewis, Amanda L Lewis
The gut harbors many symbiotic, commensal, and pathogenic microbes that engage in the breakdown and metabolism of host carbohydrates. Sialic acids are prominent outermost carbohydrates on mucins and protect underlying glycan chains from enzymatic degradation. Sialidases produced by some members of the colonic microbiota have been shown to promote the expansion of several potential pathogens (e.g. Clostridium difficile, Salmonella, Escherichia coli) that do not produce sialidases. O-acetyl ester modifications of sialic acids help resist the action of many sialidases and are found at high levels in the mammalian colon...
May 19, 2017: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/28522685/correction-self-reactive-vh4-34-expressing-igg-b-cells-recognize-commensal-bacteria
#3
Jean-Nicolas Schickel, Salomé Glauzy, Yen-Shing Ng, Nicolas Chamberlain, Christopher Massad, Isabelle Isnardi, Nathan Katz, Gulbu Uzel, Steven M Holland, Capucine Picard, Anne Puel, Jean-Laurent Casanova, Eric Meffre
No abstract text is available yet for this article.
May 18, 2017: Journal of Experimental Medicine
https://www.readbyqxmd.com/read/28518215/the-tlr9-signaling-pathway-regulates-mr1-mediated-bacterial-antigen-presentation-in-b-cells
#4
Jianyun Liu, Randy R Brutkiewicz
Mucosal-associated invariant T (MAIT) cells are conserved T cells that express a semi-invariant TCR (Vα7.2 in humans and Vα19 in mice). The development of MAIT cells requires the antigen (Ag) presenting MHC-related protein 1 (MR1), as well as commensal bacteria. The mechanisms that regulate the functional expression of MR1 molecules and their loading with bacterial Ag in APCs are largely unknown. We have found that treating B cells with the TLR9 agonist CpG increases MR1 surface expression. Interestingly, activation of TLR9 by CpG-A (but not CpG-B) enhances MR1 surface expression...
May 18, 2017: Immunology
https://www.readbyqxmd.com/read/28513418/flagellar-expression-in-clinical-isolates-of-non-typeable-haemophilus-influenzae
#5
Alejandro Carabarin-Lima, Patricia Lozano-Zarain, Miguel Castañeda-Lucio, Claudia Fabiola Martínez de la Peña, Julieta Martinez-Garcia, Norarizbeth Lara Flores, Elías Campos de la Cruz, Sirenia González-Posos, Rosa Del Carmen Rocha-Gracia
PURPOSE: Haemophilus influenzae is a commensal organism found in the upper respiratory tract of humans. When H. influenzae becomes a pathogen, these bacteria can move out of their commensal niche and cause multiple respiratory tract diseases such as otitis media, sinusitis, conjunctivitis and bronchitis in children, and chronic obstructive pulmonary disease in adults. However, H. influenzae is currently considered a non-flagellate bacterium. METHODOLOGY AND RESULTS: In this study, 90 clinical isolates of H...
May 18, 2017: Journal of Medical Microbiology
https://www.readbyqxmd.com/read/28511691/tomato-root-microbiota-and-phytophthora-parasitica-associated-disease
#6
Marie Larousse, Corinne Rancurel, Camille Syska, Ferran Palero, Catherine Etienne, Benoît Industri, Xavier Nesme, Marc Bardin, Eric Galiana
BACKGROUND: Interactions between pathogenic oomycetes and microbiota residing on the surface of the host plant root are unknown, despite being critical to inoculum constitution. The nature of these interactions was explored for the polyphagous and telluric species Phytophthora parasitica. RESULTS: Composition of the rhizospheric microbiota of Solanum lycopersicum was characterized using deep re-sequencing of 16S rRNA gene to analyze tomato roots either free of or partly covered with P...
May 16, 2017: Microbiome
https://www.readbyqxmd.com/read/28506730/-the-human-gut-microbiota-interactions-with-the-host-and-dysfunctions
#7
P Lepage
The human intestinal microbiota is composed of approximately 100,000 billion microorganisms with the average total number of different commensal bacterial species estimated at over 500 per individual. The human intestinal microbiota can be considered as an organ within another, which co-evolved with its host to achieve a symbiotic relationship leading to physiological homeostasis. The host provides an environment enriched in nutrients and the microbiota provides essential functions. Dysbiosis of the intestinal microbiota (changes in bacterial composition) has been associated with local dysfunctions of the gastrointestinal tract, such as inflammatory bowel disease or irritable bowel syndrome but also with obesity and metabolic diseases...
May 12, 2017: Revue des Maladies Respiratoires
https://www.readbyqxmd.com/read/28503071/the-ecological-community-of-commensal-symbiotic-and-pathogenic-gastrointestinal-microorganisms-an-appraisal
#8
REVIEW
Seraj Zohurul Haque, Mainul Haque
The human gastrointestinal tract is inhabited by a vast population of bacteria, numbering ~100 trillion. These microorganisms have been shown to play a significant role in digestion, metabolism, and the immune system. The aim of this study was to review and discuss how the human body interacts with its gut microbiome and in turn the effects that the microorganisms have on its host, overall resulting in a true mutualistic relationship.
2017: Clinical and Experimental Gastroenterology
https://www.readbyqxmd.com/read/28502123/novel-method-for-the-depletion-of-cariogenic-bacteria-using-dextranomer-microspheres
#9
Lauren Mashburn-Warren, Jennifer S Downey, Steven D Goodman
Streptococcus mutans is recognized as one of the key contributors to the dysbiotic state that results in dental caries. While existing treatment strategies reduce the incidence of tooth decay, they also eliminate both the cariogenic and beneficial microbes. Here we introduce a novel treatment alternative using Sephadex, cross-linked dextranomer microspheres (DMs), typically used for gel filtration chromatography. In addition DM beads can be used for affinity purification of glucosyltransferases (GTFs) from S...
May 14, 2017: Molecular Oral Microbiology
https://www.readbyqxmd.com/read/28500047/self-reactive-vh4-34-expressing-igg-b-cells-recognize-commensal-bacteria
#10
Jean-Nicolas Schickel, Salomé Glauzy, Yen-Shing Ng, Nicolas Chamberlain, Christopher Massad, Isabelle Isnardi, Nathan Katz, Gulbu Uzel, Steven M Holland, Capucine Picard, Anne Puel, Jean-Laurent Casanova, Eric Meffre
The germline immunoglobulin (Ig) variable heavy chain 4-34 (VH4-34) gene segment encodes in humans intrinsically self-reactive antibodies that recognize I/i carbohydrates expressed by erythrocytes with a specific motif in their framework region 1 (FWR1). VH4-34-expressing clones are common in the naive B cell repertoire but are rarely found in IgG memory B cells from healthy individuals. In contrast, CD27(+)IgG(+) B cells from patients genetically deficient for IRAK4 or MYD88, which mediate the function of Toll-like receptors (TLRs) except TLR3, contained VH4-34-expressing clones and showed decreased somatic hypermutation frequencies...
May 12, 2017: Journal of Experimental Medicine
https://www.readbyqxmd.com/read/28497768/antibacterial-effects-of-antiretrovirals-potential-implications-for-microbiome-studies-in-hiv
#11
Mohaned Shilaih, Daniel C Angst, Alex Marzel, Sebastian Bonhoeffer, Huldrych F Günthard, Roger D Kouyos
BACKGROUND: Despite being used by more than 18 million people our understanding of the extent of effects of antiretrovirals on the human body and other organisms remains incomplete. In addition, the direct effect of antiretrovirals on the gut microbiota of HIV infected individuals has been largely overlooked in microbiome studies concerned with HIV infected individuals. METHODS: Here we tested 25 antiretrovirals on Bacillus subtilis and Escherichia coli using a broth microdilution assay to assess whether these drugs have an antibacterial effect...
May 12, 2017: Antiviral Therapy
https://www.readbyqxmd.com/read/28496444/the-transcription-factor-c-maf-promotes-the-differentiation-of-follicular-helper-t-cells
#12
Fabienne Andris, Sébastien Denanglaire, Maelle Anciaux, Mélanie Hercor, Hind Hussein, Oberdan Leo
Follicular helper T cells (Tfh) have been identified as the primary cell subpopulation regulating B cell responses in germinal centers, thus supporting high-affinity antibody production. Among the transcription factors orchestrating Tfh cell differentiation and function, the role played by the proto-oncogene c-Maf remains poorly characterized. We report herein that selective loss of c-Maf expression in the T cell compartment results in defective development of Tfh cells in response to both antigen/adjuvant vaccinations and commensal intestinal bacteria...
2017: Frontiers in Immunology
https://www.readbyqxmd.com/read/28494240/cooperating-commensals-restore-colonization-resistance-to-vancomycin-resistant-enterococcus-faecium
#13
Silvia Caballero, Sohn Kim, Rebecca A Carter, Ingrid M Leiner, Bože Sušac, Liza Miller, Grace J Kim, Lilan Ling, Eric G Pamer
Antibiotic-mediated microbiota destruction and the consequent loss of colonization resistance can result in intestinal domination with vancomycin-resistant Enterococcus (VRE), leading to bloodstream infection in hospitalized patients. Clearance of VRE remains a challenging goal that, if achieved, would reduce systemic VRE infections and patient-to-patient transmission. Although obligate anaerobic commensal bacteria have been associated with colonization resistance to VRE, the specific bacterial species involved remain undefined...
May 10, 2017: Cell Host & Microbe
https://www.readbyqxmd.com/read/28494236/allied-commensal-forces-against-vancomycin-resistant-enterococci
#14
Brayon J Fremin, Ami S Bhatt
In this issue of Cell Host & Microbe, Caballero et al. (2017) define a precise, limited consortium of commensal bacteria that restores resistance to colonization by clinically vexing vancomycin-resistant Enterococcus species.
May 10, 2017: Cell Host & Microbe
https://www.readbyqxmd.com/read/28494209/antibiotic-resistance-virulence-factors-and-biofilm-formation-ability-in-escherichia-coli-strains-isolated-from-chicken-meat-and-wildlife-in-the-czech-republic
#15
Silvie Pavlickova, Anja Klancnik, Magda Dolezalova, Sonja Smole Mozina, Ivan Holko
Attachment of pathogenic bacteria to food contact surfaces and the subsequent biofilm formation represent a serious threat for the food industry, since these bacteria are more resistant to antimicrobials or possess more virulence factors. The main aim of this study was to investigate the correlation between antibiotic resistance against 13 antibiotics, distribution of 10 virulence factors and biofilm formation in 105 Escherichia coli strains according to their origin. The high prevalence of antibiotic resistance that we have found in wildlife isolates could be acquired by horizontal transfer of resistance genes from human or domestic or farm animals...
May 11, 2017: Journal of Environmental Science and Health. Part. B, Pesticides, Food Contaminants, and Agricultural Wastes
https://www.readbyqxmd.com/read/28491823/comparative-proteomics-reveals-differences-in-host-pathogen-interaction-between-infectious-and-commensal-relationship-with-campylobacter-jejuni
#16
Nieves Ayllón, Ángeles Jiménez-Marín, Héctor Argüello, Sara Zaldívar-López, Margarita Villar, Carmen Aguilar, Angela Moreno, José De La Fuente, Juan J Garrido
Campylobacter jejuni is the leading food-borne poisoning in industrialized countries. While the bacteria causes disease in humans, it merely colonizes the gut in poultry or pigs, where seems to establish a commensal relationship. Until now, few studies have been conducted to elucidate the relationship between C. jejuni and its different hosts. In this work, a comparative proteomics approach was used to identify the underlying mechanisms involved in the divergent outcome following C. jejuni infection in human and porcine host...
2017: Frontiers in Cellular and Infection Microbiology
https://www.readbyqxmd.com/read/28490053/prebiotic-effect-of-xylooligosaccharides-produced-from-birchwood-xylan-by-a-novel-fungal-gh11-xylanase
#17
Manuel Nieto-Domínguez, Laura I de Eugenio, María J York-Durán, Barbara Rodríguez-Colinas, Francisco J Plou, Empar Chenoll, Ester Pardo, Francisco Codoñer, María Jesús Martínez
A fungal endoxylanase belonging to the glycoside hydrolase gene family 11 (GH11) was obtained from the ascomycete Talaromyces amestolkiae. The enzyme was purified, characterized and used to produce a mixture of xylooligosaccharides (XOS) from birchwood xylan. A notable yield of neutral XOS was obtained (28.8%) upon enzyme treatment and the mixture contained a negligible amount of xylose, having xylobiose, xylotriose and xylotetraose as its main components. The prebiotic potential of this mixture was demonstrated upon analyzing the variations in microorganisms' composition and organic acids profile in breast-fed child faeces fermentations...
October 1, 2017: Food Chemistry
https://www.readbyqxmd.com/read/28489497/ecology-and-genomic-insights-on-plant-pathogenic-and-nonpathogenic-endophytes
#18
Günter Brader, Stéphane Compant, Kathryn Vescio, Birgit Mitter, Friederike Trognitz, Li-Jun Ma, Angela Sessitsch
Plants are colonized on their surfaces and in the rhizosphere and phyllosphere by a multitude of different microorganisms and are inhabited internally by endophytes. Most endophytes act as commensals without any known effect on their plant host, but multiple bacteria and fungi establish a mutualistic relationship with plants, and some act as pathogens. The outcome of these plant-microbe interactions depends on biotic and abiotic environmental factors and on the genotype of the host and the interacting microorganism...
May 10, 2017: Annual Review of Phytopathology
https://www.readbyqxmd.com/read/28485690/-it-s-a-gut-feeling-escherichia-coli-biofilm-formation-in-the-gastrointestinal-tract-environment
#19
Elio Rossi, Annika Cimdins, Petra Lüthje, Annelie Brauner, Åsa Sjöling, Paolo Landini, Ute Römling
Escherichia coli can commonly be found, either as a commensal, probiotic or a pathogen, in the human gastrointestinal (GI) tract. Biofilm formation and its regulation is surprisingly variable, although distinct regulatory pattern of red, dry and rough (rdar) biofilm formation arise in certain pathovars and even clones. In the GI tract, environmental conditions, signals from the host and from commensal bacteria contribute to shape E. coli biofilm formation within the multi-faceted multicellular communities in a complex and integrated fashion...
May 9, 2017: Critical Reviews in Microbiology
https://www.readbyqxmd.com/read/28485146/effects-of-growth-surface-topography-on-bacterial-signaling-in-coculture-biofilms
#20
Arunima Bhattacharjee, Mughees Khan, Maya Kleiman, Allon I Hochbaum
Bacteria form interface-associated communities, called biofilms, often comprising multiple species. Biofilms can be detrimental or beneficial in medical, industrial, and technological settings, and their stability and function are determined by interspecies communication via specific chemical signaling or metabolite exchange. The deterministic control of biofilm development, behavior, and properties remains an unmet challenge limiting our ability to inhibit formation of detrimental biofilms in biomedical settings and promote the growth of beneficial biofilms in biotechnology applications...
May 9, 2017: ACS Applied Materials & Interfaces
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