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https://www.readbyqxmd.com/read/28331079/characterization-and-vaccine-potential-of-membrane-vesicles-produced-by-francisella-noatunensis-sup-orientalis-in-an-adult-zebrafish-model
#1
Leidy Lagos, Julia I Tandberg, Urska Repnik, Preben Boysen, Erik Ropstad, Deepa Varkey, Ian T Paulsen, Hanne C Winther-Larsen
Vaccine development against extracellular bacteria has been important for the sustainability of the aquaculture industry. In contrast, infections with intracellular pathogens remain largely an unresolved problem. Francisella noatunensis subspecies orientalis (Fno) are Gram-negative, facultative intracellular bacteria that cause the disease francisellosis in fish. Francisellosis is commonly characterized as a chronic granulomatous disease with high morbidity and can result in high mortality depending on the host...
March 22, 2017: Clinical and Vaccine Immunology: CVI
https://www.readbyqxmd.com/read/28329722/antibacterial-properties-of-amino-acid-functionalized-silver-nanoparticles-decorated-on-graphene-oxide-sheets
#2
Kumudini Chandraker, Rekha Nagwanshi, S K Jadhav, Kallol K Ghosh, Manmohan L Satnami
Graphene oxide (GO) sheets decorated with amino acid L-cysteine (L-cys) functionalized silver nanoparticles (GO-L-cys-Ag) was synthesized by AgNO3, trisodium citrate, and NaBH4. GO-L-cys-Ag nanocomposite was characterized by transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectra, ultraviolet-visible (UV-vis) absorption spectra, which demonstrated that a diameter of L-cys-AgNPs compactly deposited on GO. Antibacterial activity tests of GO-L-cys-Ag nanocomposite were carried out using Escherichia coli MTCC 1687 and Staphylococcus aureus MTCC 3160 as model strains of Gram-negative and Gram-positive bacteria, respectively...
March 16, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/28327506/efficacy-and-safety-evaluation-of-a-chlorine-dioxide-solution
#3
Jui-Wen Ma, Bin-Syuan Huang, Chu-Wei Hsu, Chun-Wei Peng, Ming-Long Cheng, Jung-Yie Kao, Tzong-Der Way, Hao-Chang Yin, Shan-Shue Wang
In this study, a chlorine dioxide solution (UC-1) composed of chlorine dioxide was produced using an electrolytic method and subsequently purified using a membrane. UC-1 was determined to contain 2000 ppm of gaseous chlorine dioxide in water. The efficacy and safety of UC-1 were evaluated. The antimicrobial activity was more than 98.2% reduction when UC-1 concentrations were 5 and 20 ppm for bacteria and fungi, respectively. The half maximal inhibitory concentrations (IC50) of H1N1, influenza virus B/TW/71718/04, and EV71 were 84...
March 22, 2017: International Journal of Environmental Research and Public Health
https://www.readbyqxmd.com/read/28325767/cohesive-properties-of-the-caulobacter-crescentus-holdfast-adhesin-are-regulated-by-a-novel-c-di-gmp-effector-protein
#4
Kathrin S Sprecher, Isabelle Hug, Jutta Nesper, Eva Potthoff, Mohamed-Ali Mahi, Matteo Sangermani, Volkhard Kaever, Torsten Schwede, Julia Vorholt, Urs Jenal
When encountering surfaces, many bacteria produce adhesins to facilitate their initial attachment and to irreversibly glue themselves to the solid substrate. A central molecule regulating the processes of this motile-sessile transition is the second messenger c-di-GMP, which stimulates the production of a variety of exopolysaccharide adhesins in different bacterial model organisms. In Caulobacter crescentus, c-di-GMP regulates the synthesis of the polar holdfast adhesin during the cell cycle, yet the molecular and cellular details of this control are currently unknown...
March 21, 2017: MBio
https://www.readbyqxmd.com/read/28325766/staphylococcal-%C3%AE-toxin-modulates-human-aortic-endothelial-cell-and-platelet-function-through-sphingomyelinase-and-biofilm-ligase-activities
#5
Alfa Herrera, Katarina Kulhankova, Vijay K Sonkar, Sanjana Dayal, Aloysius J Klingelhutz, Wilmara Salgado-Pabón, Patrick M Schlievert
Staphylococcus aureus causes many infections, such as skin and soft tissue, pneumonia, osteomyelitis, and infective endocarditis (IE). IE is an endovascular infection of native and prosthetic valves and the lining of the heart; it is characterized by the formation of cauliflower-like "vegetations" composed of fibrin, platelets, other host factors, bacteria, and bacterial products. β-Toxin is an S. aureus virulence factor that contributes to the microorganism's ability to cause IE. This cytolysin has two enzymatic activities: sphingomyelinase (SMase) and biofilm ligase...
March 21, 2017: MBio
https://www.readbyqxmd.com/read/28323617/cryoem-structures-of-membrane-pore-and-prepore-complex-reveal-cytolytic-mechanism-of-pneumolysin
#6
Katharina van Pee, Alexander Neuhaus, Edoardo D'Imprima, Deryck J Mills, Werner Kühlbrandt, Özkan Yildiz
Many pathogenic bacteria produce pore-forming toxins to attack and kill human cells. We have determined the 4.5 Å structure of the ~2.2 MDa pore complex of pneumolysin, the main virulence factor of Streptococcus pneumoniae, by cryoEM. The pneumolysin pore is a 400 Å ring of 42 membrane-inserted monomers. Domain D3 of the soluble toxin refolds into two ~85 Å β-hairpins that traverse the lipid bilayer and assemble into a 168-strand β-barrel. The pore complex is stabilized by salt bridges between β-hairpins of adjacent subunits and an internal α-barrel...
March 21, 2017: ELife
https://www.readbyqxmd.com/read/28323277/an-alternative-polysaccharide-uptake-mechanism-of-marine-bacteria
#7
Greta Reintjes, Carol Arnosti, Bernhard M Fuchs, Rudolf Amann
Heterotrophic microbial communities process much of the carbon fixed by phytoplankton in the ocean, thus having a critical role in the global carbon cycle. A major fraction of the phytoplankton-derived substrates are high-molecular-weight (HMW) polysaccharides. For bacterial uptake, these substrates must initially be hydrolysed to smaller sizes by extracellular enzymes. We investigated polysaccharide hydrolysis by microbial communities during a transect of the Atlantic Ocean, and serendipitously discovered-using super-resolution structured illumination microscopy-that up to 26% of total cells showed uptake of fluorescently labelled polysaccharides (FLA-PS)...
March 21, 2017: ISME Journal
https://www.readbyqxmd.com/read/28323072/impairment-of-the-class-iia-bacteriocin-receptor-function-and-membrane-structural-changes-are-associated-to-enterocin-crl35-high-resistance-in-listeria-monocytogenes
#8
Emilse Masias, Fernando G Dupuy, Paulo Ricardo da Silva Sanches, Juan Vicente Farizano, Eduardo Cilli, Augusto Bellomio, Lucila Saavedra, Carlos Minahk
BACKGROUND: Enterocin CRL35 is a class IIa bacteriocin with anti-Listeria activity. Resistance to these peptides has been associated with either the downregulation of the receptor expression or changes in the membrane and cell walls. The scope of the present work was to characterize enterocin CRL35 resistant Listeria strains with MICs more than 10,000 times higher than the MIC of the WT sensitive strain. METHODS: Listeria monocytogenes INS7 resistant isolates R2 and R3 were characterized by 16S RNA gene sequencing and rep-PCR...
March 17, 2017: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/28322271/mechanistic-and-structural-basis-of-bioengineered-bovine-cathelicidin-5-with-optimized-therapeutic-activity
#9
Bikash R Sahoo, Kenta Maruyama, Jyotheeswara R Edula, Takahiro Tougan, Yuxi Lin, Young-Ho Lee, Toshihiro Horii, Toshimichi Fujiwara
Peptide-drug discovery using host-defense peptides becomes promising against antibiotic-resistant pathogens and cancer cells. Here, we customized the therapeutic activity of bovine cathelicidin-5 targeting to bacteria, protozoa, and tumor cells. The membrane dependent conformational adaptability and plasticity of cathelicidin-5 is revealed by biophysical analysis and atomistic simulations over 200 μs in thymocytes, leukemia, and E. coli cell-membranes. Our understanding of energy-dependent cathelicidin-5 intrusion in heterogeneous membranes aided in designing novel loss/gain-of-function analogues...
March 21, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28321528/silver-nanoparticles-against-salmonella-enterica-serotype-typhimurium-role-of-inner-membrane-dysfunction
#10
Minju Seong, Dong Gun Lee
The evolution of antibiotics-resistant bacteria is considered a major concern. To explore promising antibacterial materials and clarify their unknown mechanisms, the mode of action of silver nanoparticles (AgNPs) against Salmonella enterica serotype typhimurium was investigated. We investigated the effect of AgNPs on the bacterial membrane. The N-phenyl-1-naphthylamine assay showed that the permeability of the outer membrane was not changed by treatment with AgNPs. The O-nitrophenyl-β-D-galactopyranoside assay showed that the inner membrane permeability increased as AgNPs concentration increased...
March 21, 2017: Current Microbiology
https://www.readbyqxmd.com/read/28320885/identification-of-the-lyso-form-n-acyl-intramolecular-transferase-in-low-gc-firmicutes
#11
Krista M Armbruster, Timothy C Meredith
Bacterial lipoproteins are embedded in the cell membrane of both Gram-positive and Gram-negative bacteria where they serve numerous functions central to cell envelope physiology. Lipoproteins are tethered to the membrane by an N-acyl-S-(mono/di)-acyl-glyceryl-cysteine anchor that is variably acylated depending on genera. In several low-GC Gram-positive Firmicutes, a monoacyl-glyceryl-cysteine with an N-terminal fatty acid (known as the lyso form) has been reported, though how it is formed is unknown. Here, through an intergenic complementation rescue assay in Escherichia coli, we report the identification of a common orthologous transmembrane protein in both Enterococcus faecalis and Bacillus cereus capable of forming lyso-form lipoproteins...
March 20, 2017: Journal of Bacteriology
https://www.readbyqxmd.com/read/28320881/lpto-pg0027-is-required-for-lipid-a-1-phosphatase-activity-in-porphyromonas-gingivalis-w50
#12
Minnie Rangarajan, Joseph Aduse-Opoku, Ahmed Hashim, Graham McPhail, Zofia Luklinska, M Florencia Haurat, Mario F Feldman, Michael A Curtis
Porphyromonas gingivalis produces outer-membrane vesicles (OMVs) rich in virulence factors including cysteine-proteases and A-LPS, one of the two lipopolysaccharides (LPS) produced by this organism. Previous studies had suggested that A-LPS together with PG0027, an outer-membrane (OM) protein, may be involved in OMV-formation. Their roles in this process were examined using parent W50 and mutant ΔPG0027 strains. Inactivation of PG0027 caused a reduction in yield of OMVs. Lipid A from cells and OMVs of P. gingivalis W50 and ΔPG0027 strains were analysed by matrix-assisted laser-desorption-ionisation-time of flight mass spectrometry (MALDI-TOF- MS)...
March 20, 2017: Journal of Bacteriology
https://www.readbyqxmd.com/read/28319867/phototherapeutic-spectrum-expansion-through-synergistic-effect-of-mesoporous-silica-trio-nanohybrids-against-antibiotic-resistant-gram-negative-bacterium
#13
Yaswanth Kuthati, Ranjith Kumar Kankala, Prabhakar Busa, Shi-Xiang Lin, Jin-Pei Deng, Chung-Yuan Mou, Chia-Hung Lee
The extensive impact of antibiotic resistance has led to the exploration of new anti-bacterial modalities. We designed copper impregnated mesoporous silica nanoparticles (Cu-MSN) with immobilizing silver nanoparticles (SNPs) to apply photodynamic inactivation (PDI) of antibiotic-resistant E. coli. SNPs were decorated over the Cu-MSN surfaces by coordination of silver ions on diamine-functionalized Cu-MSN and further reduced to silver nanoparticles with formalin. We demonstrate that silver is capable of sensitizing the gram-negative bacteria E...
March 7, 2017: Journal of Photochemistry and Photobiology. B, Biology
https://www.readbyqxmd.com/read/28317932/bacterial-secretion-system-skews-the-fate-of-legionella-containing-vacuoles-towards-lc3-associated-phagocytosis
#14
Andree Hubber, Tomoko Kubori, Cevayir Coban, Takeshi Matsuzawa, Michinaga Ogawa, Tsuyoshi Kawabata, Tamotsu Yoshimori, Hiroki Nagai
The evolutionarily conserved processes of endosome-lysosome maturation and macroautophagy are established mechanisms that limit survival of intracellular bacteria. Similarly, another emerging mechanism is LC3-associated phagocytosis (LAP). Here we report that an intracellular vacuolar pathogen, Legionella dumoffii, is specifically targeted by LAP over classical endocytic maturation and macroautophagy pathways. Upon infection, the majority of L. dumoffii resides in ER-like vacuoles and replicate within this niche, which involves inhibition of classical endosomal maturation...
March 20, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28317443/deterioration-of-the-anammox-process-at-decreasing-temperatures-and-long-srts
#15
Maaike Hoekstra, Florence A de Weerd, Robbert Kleerebezem, Mark C M van Loosdrecht
The implementation of autotrophic nitrogen removal in the mainstream of a municipal wastewater treatment plant is currently pursued. Among the crucial unknown factors are the kinetic properties of anaerobic ammonium oxidising (anammox) bacteria at low temperatures, as typically encountered for sewage in winter. In this study we investigated the adaptation of a fast growing anammox culture to a lower temperature. In a membrane bioreactor a highly enriched anammox community was obtained at 30, 25 and 20°C. The culture grew as free cells and small flocs (50 -150µm)...
March 19, 2017: Environmental Technology
https://www.readbyqxmd.com/read/28314230/toxicity-of-diatom-polyunsaturated-aldehydes-to-marine-bacterial-isolates-reveals-their-mode-of-action
#16
Milva Pepi, Hermann J Heipieper, Cecilia Balestra, Marco Borra, Elio Biffali, Raffaella Casotti
Diatoms produce and release polyunsaturated aldehydes (PUAs) during senescence in culture and at the end of blooms in nature and these compounds play different ecological roles, as infochemicals, allelochemicals and pheromones In order to elucidate the toxic effects of PUAs, we isolated six bacterial strains from the Mediterranean Sea during a diatom bloom and tested their tolerance to PUA in terms of growth and cell membrane properties. Based upon 16S rRNA sequencing, these bacteria were assigned to the genera Pseudomonas, Sufflavibacter, Halomonas, Vibrio, Idiomarina, and Labrenzia...
March 9, 2017: Chemosphere
https://www.readbyqxmd.com/read/28301286/chlorine-dioxide-oxidation-of-escherichia-coli-in-water-a-study-of-the-disinfection-kinetics-and-mechanism
#17
Isaac Ofori, Suresh Maddila, Johnson Lin, Sreekantha B Jonnalagadda
This study investigated the kinetics and mechanism of chlorine dioxide (ClO2) inactivation of a Gram-negative bacteria Escherichia coli (ATCC 35218) in oxidant demand free (ODF) water in detail as a function of disinfectant concentration (0.5-5.0 mg/L), water pH (6.5-8.5), temperature variations (4-37°C) and bacterial density (10(5)-10(7) cfu/mL). The effects of ClO2 on bacterial cell morphology, outer membrane permeability, cytoplasmic membrane disruption and intracellular enzymatic activity were also studied to elucidate the mechanism of action on the cells...
March 16, 2017: Journal of Environmental Science and Health. Part A, Toxic/hazardous Substances & Environmental Engineering
https://www.readbyqxmd.com/read/28300180/systems-level-understanding-of-ethanol-induced-stresses-and-adaptation-in-e-coli
#18
Huansheng Cao, Du Wei, Yuedong Yang, Yu Shang, Gaoyang Li, Yaoqi Zhou, Qin Ma, Ying Xu
Understanding ethanol-induced stresses and responses in biofuel-producing bacteria at systems level has significant implications in engineering more efficient biofuel producers. We present a computational study of transcriptomic and genomic data of both ethanol-stressed and ethanol-adapted E. coli cells with computationally predicated ethanol-binding proteins and experimentally identified ethanol tolerance genes. Our analysis suggests: (1) ethanol damages cell wall and membrane integrity, causing increased stresses, particularly reactive oxygen species, which damages DNA and reduces the O2 level; (2) decreased cross-membrane proton gradient from membrane damage, coupled with hypoxia, leads to reduced ATP production by aerobic respiration, driving cells to rely more on fatty acid oxidation, anaerobic respiration and fermentation for ATP production; (3) the reduced ATP generation results in substantially decreased synthesis of macromolecules; (4) ethanol can directly bind 213 proteins including transcription factors, altering their functions; (5) all these changes together induce multiple stress responses, reduced biosynthesis, cell viability and growth; and (6) ethanol-adapted E...
March 16, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28300142/late-assembly-of-the-vibrio-cholerae-cell-division-machinery-postpones-septation-to-the-last-10-of-the-cell-cycle
#19
Elisa Galli, Evelyne Paly, François-Xavier Barre
Bacterial cell division is a highly regulated process, which involves the formation of a complex apparatus, the divisome, by over a dozen proteins. In the few model bacteria in which the division process was detailed, divisome assembly occurs in two distinct steps: a few proteins, including the FtsZ tubulin-like protein, form a membrane associated contractile ring, the Z-ring, at ~30% of the cell cycle. The Z-ring serves as a scaffold for the recruitment of a second series of proteins, including integral membrane and periplasmic cell wall remodelling enzymes, at ~50% of the cell cycle...
March 16, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28299865/novel-short-antimicrobial-peptide-isolated-from-xenopus-laevis-skin
#20
Yu Zhang, Songcai Liu, Siming Li, Yunyun Cheng, Linyan Nie, Gang Wang, Chen Lv, Wenzhen Wei, Cheng Cheng, Feng Hou, Linlin Hao
A rich source of bioactive peptides, including a large number of antimicrobial peptides, has been found in amphibian skin. In this study, a novel short antimicrobial peptide was purified from Xenopus laevis skin and characterised through reversed-phase high-performance liquid chromatography, Edman degradation and matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry. The peptide was composed of six amino acids with a sequence of DEDLDE and thus named X. laevis antibacterial peptide-P2 (XLAsp-P2)...
March 16, 2017: Journal of Peptide Science: An Official Publication of the European Peptide Society
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