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Microbiology

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https://www.readbyqxmd.com/read/28809156/the-length-of-poly-c-stretch-in-the-bordetella-pertussis-pfim3-promoter-determines-the-vag-or-vrg-function-of-the-fim3-gene
#1
Nao Otsuka, Nicole Guiso, Valérie Bouchez
Bordetella pertussis, a human pathogenic bacterium, produces either one or two types of serologically distinct fimbriae, Fim2 and Fim3, as virulence factors. The expression of fim2 and fim3 is regulated by the BvgAS two-component system and the length of poly(C) stretches in Pfim promoters. In the Bvg+ phase, B. pertussis virulence-activated genes (vags) are up-regulated and virulence-repressed genes (vrgs) are down-regulated. Previous studies have shown that fim2 is a vag, but there is no consensus on fim3 regulation...
August 15, 2017: Microbiology
https://www.readbyqxmd.com/read/28809155/microbe-profile-candida-albicans-a-shape-changing-opportunistic-pathogenic-fungus-of-humans
#2
Neil A R Gow, Bhawna Yadav
(a) Morphotypes of Candida albicans (blue sector, vegetative forms; pink sector, forms related to mating or changes in ploidy). Cell types shown include: budding yeast cells; elongated conjoined yeasts forming pseudohyphae; parallel-sided hyphae; chlamydospores formed from suspensor cells; enlarged goliath cells formed under zinc deprivation (unpublished study, image from Duncan Wilson); intestinal gut form cells (image from Suzanne Noble); mating competence defined by white-grey-opaque cell transitions (images from Guanghua Huang); elongated chemotactic shmoo-mating projections leading to tetraploid zygote formation (images from David Soll and Karla Daniels); trimera formed by unequal chromosome segregation under antifungal exposure (image from Judith Berman)...
August 15, 2017: Microbiology
https://www.readbyqxmd.com/read/28795660/systems-and-synthetic-biology-perspective-of-the-versatile-plant-pathogenic-and-polysaccharide-producing-bacterium-xanthomonas-campestris
#3
Sarah Schatschneider, Jessica Schneider, Jochen Blom, Fabien Létisse, Karsten Niehaus, Alexander Goesmann, Frank-Jörg Vorhölter
Bacteria of the genus Xanthomonas are a major group of plant pathogens. They are hazardous to important crops and closely related to human pathogens. Being collectively a major focus of molecular phytopathology, an increasing number of diverse and intricate mechanisms are emerging by which they communicate, interfere with host signalling and keep competition at bay. Interestingly, they are also biotechnologically relevant polysaccharide producers. Systems biotechnology techniques have revealed their central metabolism and a growing number of remarkable features...
August 10, 2017: Microbiology
https://www.readbyqxmd.com/read/28777072/dissecting-the-protein-architecture-of-dna-binding-transcription-factors-in-bacteria-and-archaea
#4
Nancy Rivera-Gómez, Mario Alberto Martínez-Núñez, Nina Pastor, Katya Rodriguez-Vazquez, Ernesto Perez-Rueda
Gene regulation at the transcriptional level is a central process in all organisms where DNA-binding transcription factors play a fundamental role. This class of proteins binds specifically at DNA sequences, activating or repressing gene expression as a function of the cell's metabolic status, operator context and ligand-binding status, among other factors, through the DNA-binding domain (DBD). In addition, TFs may contain partner domains (PaDos), which are involved in ligand binding and protein-protein interactions...
August 4, 2017: Microbiology
https://www.readbyqxmd.com/read/28771131/comparative-proteomic-profiles-reveal-characteristic-mycobacterium-tuberculosis-proteins-induced-by-cholesterol-during-dormancy-conditions
#5
Lazaro Garcia-Morales, Lizbel Leon-Solis, Irma E Monroy-Muñoz, Moises Talavera-Paulin, Jeanet Serafin-López, Iris Estrada-Garcia, Sandra Rivera-Gutierrez, Jorge F Cerna-Cortes, Addy C Helguera-Repetto, Jorge A Gonzalez-Y-Merchand
Cholesterol has been reported to play an important role during Mycobacterium tuberculosis infection and during its dormant state inside the host. We present the determination of proteomic profiles of M. tuberculosis H37Rv in the presence of cholesterol as the sole carbon source under exponential growth and in two in vitro dormancy phases (NRP1 and NRP2). Using 2D-PAGE, we detected that M. tuberculosis expressed a high diversity of proteins in both exponential and non-replicative phases. We also found that cholesterol was involved in the overexpression of some proteins related to sulfur metabolism (CysA2), electron transport (FixB), cell wall synthesis (Ald), iron storage (BfrB), protein synthesis (Tig and EF-Tu) and dormancy maintenance (HspX and TB 31...
August 4, 2017: Microbiology
https://www.readbyqxmd.com/read/28771130/indigenous-lactobacilli-strains-of-food-and-human-sources-reverse-enteropathogenic-e-coli-o26-h11-induced-damage-in-intestinal-epithelial-cell-lines-effect-on-redistribution-of-tight-junction-proteins
#6
Ruchi Jariwala, Hemanti Mandal, Tamishraha Bagchi
The aim of the study was to investigate the neutralizing effect of lactobacilli isolated from indigenous food and human sources on enteropathogenic Escherichia coli (EPEC) O26 : H11-induced epithelial barrier dysfunction in vitro. This was assessed by transepithelial electrical resistance (TEER) and permeability assays using intestinal cell lines, HT-29 and Caco-2. Furthermore, the expression and distribution of tight junction (TJ) proteins were analysed by qRT-PCR and immunofluorescence assay, respectively...
August 4, 2017: Microbiology
https://www.readbyqxmd.com/read/28771127/interactions-between-host-immune-response-and-antigenic-variation-that-control-borrelia-burgdorferi-population-dynamics
#7
Wei Zhou, Dustin Brisson
The population dynamics of pathogens within hosts result from interactions between host immune responses and mechanisms of the pathogen to evade or resist immune responses. Vertebrate hosts have evolved adaptive immune responses to eliminate the infection, while many pathogens evade immune clearance through altering surface antigens. Such interactions can result in a characteristic pattern of pathogen population dynamics within hosts consisting of population growth after infection, rapid population decline following specific immune responses, followed by persistence at low densities during a chronic infection stage...
August 4, 2017: Microbiology
https://www.readbyqxmd.com/read/28758636/the-pseudomonas-aeruginosa-dnak-gene-is-involved-in-bacterial-translocation-across-the-intestinal-epithelial-cell-barrier
#8
Jun Okuda, Satoshi Yamane, Syouya Nagata, Chinami Kunikata, Chigusa Suezawa, Masashi Yasuda
Pseudomonas aeruginosa can penetrate through polarized epithelial cell monolayers produced by the human adenocarcinoma cell line Caco-2. We previously identified genes associated with bacterial translocation through Caco-2 cell monolayers by analysing transposon insertion mutants with dramatically reduced penetration activity relative to that of the wild-type P. aeruginosa PAO1 strain. In this study, we focused on the dnaK mutant because the association between this gene and penetration activity is unknown...
July 31, 2017: Microbiology
https://www.readbyqxmd.com/read/28749328/desulfovibrio-da2_cueo-is-a-novel-multicopper-oxidase-with-cuprous-ferrous-and-phenol-oxidase-activity
#9
Stefano Mancini, Ranjeet Kumar, Veena Mishra, Marc Solioz
Desulfovibrio sp. A2 is a novel Gram-negative sulfate-reducing bacterium that was isolated from sediments of the Norilsk mining/smelting area in Russia. The organism possesses a monocistronic operon encoding a 71 kDa periplasmic multicopperoxidase, which we call DA2_CueO. Histidine-tagged DA2_CueO expressed from a plasmid in Escherichia coli and purified by Ni-NTA affinity chromatography oxidizes Cu+ and Fe2+, and exhibits phenol oxidase activity with 2,2-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid), 2,3-dihydroxybenzoic acid and 2,6-dimethoxyphenol as substrates, using O2 as the oxidant...
July 28, 2017: Microbiology
https://www.readbyqxmd.com/read/28749326/pneumococcal-neuraminidase-activates-tgf-%C3%AE-signalling
#10
Nina Gratz, Lip Nam Loh, Beth Mann, Geli Gao, Robert Carter, Jason Rosch, Elaine I Tuomanen
Neuraminidase A (NanA) is an important virulence factor that is anchored to the pneumococcal cell wall and cleaves sialic acid on host substrates. We noted that a secreted allele of NanA was over-represented in invasive pneumococcal isolates and promoted the development of meningitis when swapped into the genome of non-meningitis isolates replacing cell wall-anchored NanA. Both forms of recombinant NanA directly activated transforming growth factor (TGF)-β, increased SMAD signalling and promoted loss of endothelial tight junction ZO-1...
July 28, 2017: Microbiology
https://www.readbyqxmd.com/read/28749324/investigation-of-the-fim1-putative-pilus-locus-of-streptococcus-equi-subspecies-equi
#11
Karen Frances Steward, Carl Robinson, Duncan J Maskell, Chiara Nenci, Andrew Stephen Waller
The Gram-positive bacterium Streptococcus equi subspecies equi (S. equi) is the causative agent of strangles, among the most frequently diagnosed infectious diseases of horses worldwide. Genome analysis of S. equi strain 4047 (Se4047) identified a putative operon, Fim1, with similarity to the pilus loci of other Gram-positive bacteria. The Fim1 locus was present in all strains of S. equi and its close relative S. equi subspecies zooepidemicus (S. zooepidemicus) that have been studied to date. In this study we provide evidence that the putative structural pilus proteins, SEQ_0936 and CNE, are produced on the cell surface during in vitro growth and in vivo infection...
July 28, 2017: Microbiology
https://www.readbyqxmd.com/read/28742010/bacterial-communities-in-the-small-intestine-respond-differently-to-those-in-the-caecum-and-colon-in-mice-fed-low-and-high-fat-diets
#12
Janet C Onishi, Sara Campbell, Michael Moreau, Falshruti Patel, Andrew I Brooks, Yin Xiu Zhou, Max M Häggblom, Judith Storch
Bacterial communities in the mouse caecum and faeces are known to be altered by changes in dietary fat. The microbiota of the mouse small intestine, by contrast, has not been extensively profiled and it is unclear whether small intestinal bacterial communities shift with dietary fat levels. We compared the microbiota in the small intestine, caecum and colon in mice fed a low-fat (LF) or high-fat (HF) diet using 16S rRNA gene sequencing. The relative abundance of major phyla in the small intestine, Bacteriodetes, Firmicutes and Proteobacteria, was similar to that in the caecum and colon; the relative abundance of Verrucomicrobia was significantly reduced in the small intestine compared to the large intestine...
July 26, 2017: Microbiology
https://www.readbyqxmd.com/read/28742008/development-of-a-crispr-cas9-mediated-gene-editing-tool-in-streptomyces-rimosus
#13
Haiyan Jia, Longmei Zhang, Tongtong Wang, Jin Han, Hui Tang, Liping Zhang
Clustered regularly interspaced short palindromic repeats, associated proteins (CRISPR/Cas), has been developed into a powerful, targeted genome-editing tool in a wide variety of species. Here, we report an extensive investigation of the type II CRISPR/Cas9 system for targeted gene editing in Streptomyces rimosus. S. rimosus is used in the production of the antibiotic oxytetracycline, and its genome differs greatly from other species of the genus Streptomyces in the conserved chromosome terminal and core regions, which is of major production and scientific research value...
July 26, 2017: Microbiology
https://www.readbyqxmd.com/read/28742002/cdc42-activation-state-affects-its-localization-and-protein-levels-in-fission-yeast
#14
Miguel Estravís, Sergio Antonio Rincón, Elvira Portales, Pilar Pérez, Beatriz Santos
Rho GTPases control polarized cell growth and are well-known regulators of exocytic and endocytic processes. Cdc42 is an essential GTPase, conserved from yeast to humans, that is critical for cell polarization. Cdc42 is negatively regulated by the GTPase-activating proteins (GAPs) and the GDP dissociation inhibitors (GDIs), and positively regulated by guanine nucleotide exchange factors (GEFs). Cdc42 GTPase can be found in a GTP- or GDP-bound state, which determines the ability to bind downstream effector proteins and activate signalling pathways...
July 26, 2017: Microbiology
https://www.readbyqxmd.com/read/28721852/effective-identification-of-lactobacillus-casei-group-species-genome-based-selection-of-the-gene-mutl-as-the-target-of-a-novel-multiplex-pcr-assay
#15
Benedetta Bottari, Giovanna E Felis, Elisa Salvetti, Anna Castioni, Ilenia Campedelli, Sandra Torriani, Valentina Bernini, Monica Gatti
Lactobacillus casei,Lactobacillus paracasei and Lactobacillusrhamnosus form a closely related taxonomic group (the L. casei group) within the facultatively heterofermentative lactobacilli. Strains of these species have been used for a long time as probiotics in a wide range of products, and they represent the dominant species of nonstarter lactic acid bacteria in ripened cheeses, where they contribute to flavour development. The close genetic relationship among those species, as well as the similarity of biochemical properties of the strains, hinders the development of an adequate selective method to identify these bacteria...
July 18, 2017: Microbiology
https://www.readbyqxmd.com/read/28721850/amphotericin-b-induces-apoptosis-like-programmed-cell-death-in-naegleria-fowleri-and-naegleria-gruberi
#16
Roberto Cárdenas-Zúñiga, Angélica Silva-Olivares, José D' Artagnan Villalba-Magdaleno, Virginia Sánchez-Monroy, Jesús Serrano-Luna, Mineko Shibayama
Naegleria fowleri and Naegleria gruberi belong to the free-living amoebae group. It is widely known that the non-pathogenic species N. gruberi is usually employed as a model to describe molecular pathways in this genus, mainly because its genome has been recently described. However, N. fowleri is an aetiological agent of primary amoebic meningoencephalitis, an acute and fatal disease. Currently, the most widely used drug for its treatment is amphotericin B (AmB). It was previously reported that AmB has an amoebicidal effect in both N...
July 18, 2017: Microbiology
https://www.readbyqxmd.com/read/28714842/molecular-and-biochemical-characteristics-of-the-inulosucrase-hugo-from-streptomyces-viridochromogenes-dsm40736-t%C3%A3-494
#17
Hans-Jörg Frasch, Sander S van Leeuwen, Lubbert Dijkhuizen
Polyfructans are synthesized from sucrose by plants (mostly inulin) and by both Gram-negative and Gram-positive bacteria (mostly levan). In the phylum Actinobacteria only levan synthesis by Actinomyces species has been reported. We have identified a putative fructansucrase gene (hugO) in Streptomyces viridochromogenes DSM40736 (Tü494). HugO was heterologously expressed and biochemically characterized. HPSEC-MALLS and 2D-1H-13C nuclear magnetic resonance (NMR) spectroscopy analysis showed that the fructan polymer produced in vitro has an Molecular Weight of 2...
July 17, 2017: Microbiology
https://www.readbyqxmd.com/read/28708056/metarhizium-robertsii-produces-indole-3-acetic-acid-which-promotes-root-growth-in-arabidopsis-and-enhances-virulence-to-insects
#18
Xinggang Liao, Brian Lovett, Weiguo Fang, Raymond J St Leger
The plant root colonizing insect-pathogenic fungus Metarhizium robertsii has been shown to boost plant growth, but little is known about the responsible mechanisms. Here we show that M. robertsii promotes lateral root growth and root hair development of Arabidopsis seedlings in part through an auxin [indole-3-acetic acid (IAA)]-dependent mechanism. M. robertsii, or its auxin-containing culture filtrate promoted root proliferation, activated IAA-regulated gene expression and rescued the root hair defect of the IAA-deficient rhd6 Arabidopsis mutant...
July 15, 2017: Microbiology
https://www.readbyqxmd.com/read/28708051/ralstonia-solanacearum-novel-e3-ubiquitin-ligase-nel-effectors-ripaw-and-ripar-suppress-pattern-triggered-immunity-in-plants
#19
Masahito Nakano, Kenji Oda, Takafumi Mukaihara
Ralstonia solanacearum is the causal agent of bacterial wilt in solanaceous crops. This pathogen injects more than 70 effector proteins into host plant cells via the Hrp type III secretion system to cause a successful infection. However, the function of these effectors in plant cells, especially in the suppression of plant immunity, remains largely unknown. In this study, we characterized two Ralstonia solanacearum effectors, RipAW and RipAR, which share homology with the IpaH family of effectors from animal and plant pathogenic bacteria, that have a novel E3 ubiquitin ligase (NEL) domain...
July 15, 2017: Microbiology
https://www.readbyqxmd.com/read/28703701/mutations-in-mmpl3-alter-membrane-potential-hydrophobicity-and-antibiotic-susceptibility-in-mycobacterium-smegmatis
#20
Matthew B McNeil, Devon Dennison, Tanya Parish
MmpL3 is a promising target for novel anti-tubercular agents, with numerous compound series identified as MmpL3 inhibitors. Despite this, there is an incomplete understanding of MmpL3 function. Here we show that Mycobacterium smegmatis MmpL3 mutant strains had an altered cell wall hydrophobicity, disrupted membrane potential and growth defects in liquid media. Compensatory mutations that restored normal growth also returned membrane potential to wild-type. M. smegmatis MmpL3 mutant strains were resistant to two anti-tubercular agents, SQ109 and AU1235, but were more sensitive to rifampicin, erythromycin and ampicillin...
July 13, 2017: Microbiology
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