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https://www.readbyqxmd.com/read/28197690/improvement-of-levan-production-in-bacillus-amyloliquefaciens-through-metabolic-optimization-of-regulatory-elements
#1
Yanyan Gu, Jiayi Zheng, Jun Feng, Mingfeng Cao, Weixia Gao, Yufen Quan, Yulei Dang, Yi Wang, Shufang Wang, Cunjiang Song
Levan is a functional homopolymer of fructose with considerable applications in food, pharmaceutical and cosmetic industries. To improve the levan production in Bacillus amyloliquefaciens, the regulatory elements of sacB (encoding levansucrase) expression and levansucrase secretion were optimized. Four heterologous promoters were evaluated for sacB expression, and the Pgrac promoter led to the highest level for both sacB transcription and levansucrase enzyme activity. The levan production in the corresponding recombinant strain ΔLP-pHTPgrac reached 30...
February 14, 2017: Applied Microbiology and Biotechnology
https://www.readbyqxmd.com/read/28123183/epistatic-effect-of-tlr-1-6-and-10-polymorphisms-on-organic-dust-mediated-cytokine-response
#2
L M Smith, L A Weissenburger-Moser, A J Heires, K L Bailey, D J Romberger, T D LeVan
Exposure to organic dust from agricultural environments is associated with inflammatory respiratory conditions. The putative causal agents in organic dust include viral, microbial and fungal components, which are recognized by the family of Toll-like receptors (TLRs) and drive host innate and adaptive responses. Our aim in this study was to determine whether responsiveness to organic dust among agricultural workers was dependent on polymorphisms in the TLR10-TLR1-TLR6 gene cluster. We stimulated whole blood from 509 agricultural workers with organic dust, triacyl lipopeptide N-palmitoyl-S-dipalmitoylglyceryl Cys-Ser-(Lys)4 (Pam3CSK4) and the diacyl-lipopeptide peptidoglycan...
January 26, 2017: Genes and Immunity
https://www.readbyqxmd.com/read/28115645/evaluating-the-toxicity-of-cigarette-whole-smoke-solutions-in-an-air-liquid-interface-human-in-vitro-airway-tissue-model
#3
Xuefei Cao, Levan Muskhelishvili, John Latendresse, Patricia Richter, Robert H Heflich
Exposure to cigarette smoke causes a multitude of pathological changes leading to tissue damage and disease. Quantifying such changes in highly differentiated in vitro human tissue models may assist in evaluating the toxicity of tobacco products. In this methods development study, well-differentiated human air-liquid-interface (ALI) in vitro airway tissue models were used to assess toxicological endpoints relevant to tobacco smoke exposure. Whole mainstream smoke solutions (WSSs) were prepared from two commercial cigarettes (R60 and S60) that differ in smoke constituents when machine-smoked under International Organization for Standardization (ISO) conditions...
January 23, 2017: Toxicological Sciences: An Official Journal of the Society of Toxicology
https://www.readbyqxmd.com/read/28115097/development-of-a-nanoparticle-system-based-on-a-fructose-polymer-stability-and-drug-release-studies
#4
Antonio Tabernero, Álvaro González-Garcinuño, José Mª Sánchez-Álvarez, Miguel A Galán, Eva M Martín Del Valle
New drug delivery systems (DDSs) with levan or its carboxymethylated form, as carriers, and 5-fluorouracil as a drug, are produced in this work. Levan is obtained after cultivating A. nectaris and polymer nanoparticles are created in water by a self-assembled process. The effect of pH and the ionic strength on polymer nanoparticles aggregation is studied. Basic pHs produces a particle size between 300 and 400nm with a Z-potential around -20mV because a basic medium promotes repulsion forces. DDSs of 300-400nm and a Z-potential about -25mV are prepared by taking advantage of the amphiphilic properties of the levan...
March 15, 2017: Carbohydrate Polymers
https://www.readbyqxmd.com/read/28103254/a-highly-active-endo-levanase-bt1760-of-a-dominant-mammalian-gut-commensal-bacteroides-thetaiotaomicron-cleaves-not-only-various-bacterial-levans-but-also-levan-of-timothy-grass
#5
Karin Mardo, Triinu Visnapuu, Heiki Vija, Anneli Aasamets, Katrin Viigand, Tiina Alamäe
Bacteroides thetaiotaomicron, an abundant commensal of the human gut, degrades numerous complex carbohydrates. Recently, it was reported to grow on a β-2,6-linked polyfructan levan produced by Zymomonas mobilis degrading the polymer into fructooligosaccharides (FOS) with a cell surface bound endo-levanase BT1760. The FOS are consumed by B. thetaiotaomicron, but also by other gut bacteria, including health-promoting bifidobacteria and lactobacilli. Here we characterize biochemical properties of BT1760, including the activity of BT1760 on six bacterial levans synthesized by the levansucrase Lsc3 of Pseudomonas syringae pv...
2017: PloS One
https://www.readbyqxmd.com/read/28075130/expression-and-characterization-of-levansucrase-from-clostridium-acetobutylicum
#6
Song Gao, Xianghui Qi, Darren J Hart, Herui Gao, Yingfeng An
The Clostridium acetobutylicum gene Ca-SacB encoding levansucrase was cloned and expressed in Escherichia coli. Ca-SacB is composed of 1287 bp and encodes 428 amino acid residues, which could convert 150 mmol/L sucrose to levan with the liberation of glucose. The optimum pH and temperature of this enzyme for levan formation were pH 6 and 60 °C, respectively. Levansucrase activity of Ca-SacB was completely abolished by 5 mmol/L Ag(+) and Hg(2+). The Km and Vmax values for levansucrase were calculated to be 64 mmol/L and 190 μmol/min/mg, respectively...
February 1, 2017: Journal of Agricultural and Food Chemistry
https://www.readbyqxmd.com/read/28017156/sugar-based-biopolymers-in-nanomedicine-new-emerging-era-for-cancer-imaging-and-therapy
#7
Mehmet S Eroglu, Ebru Toksoy Oner, Esra Cansever Mutlu, Muge Sennaroglu Bostan
Since last decade, sugar based biopolymers are recognized in nanomedicine as promising materials for cancer imaging and therapy. Their durable, biocompatible and adhesive properties enable the fine tuning of their molecular weights (MW) and their miscellaneous nature makes the molecules acquire various conformations. These in turn provide effective endocytosis by cancer cell membranes that have already been programmed for internalization of different kinds of sugars. Therefore, biocompatible sugar based nanoparticles (SBNPs) are suitable for both cell-selective delivery of drugs and imaging through the human body...
December 21, 2016: Current Topics in Medicinal Chemistry
https://www.readbyqxmd.com/read/28004643/electrically-driven-magnetic-antenna-based-on-multiferroic-composites
#8
X-G Wang, A Sukhov, L Chotorlishvili, C-L Jia, G-H Guo, J Berakdar
We suggest and demonstrate via large scale numerical simulations an electrically operated spin-wave inducer based on composite multiferroic junctions. Specifically, we consider an interfacially coupled ferromagnetic/ferroelectric structure that emits controllably spin waves in the ferromagnets if the ferroelectric polarization is poled by an external electric field. The roles of geometry and material properties are discussed.
March 8, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
https://www.readbyqxmd.com/read/27987889/efficient-biosynthesis-of-levan-from-sucrose-by-a-novel-levansucrase-from-brenneria-goodwinii
#9
Qian Liu, Shuhuai Yu, Tao Zhang, Bo Jiang, Wanmeng Mu
Levan, a unique homopolysaccharide consisting of fructose residues linked by β-(2, 6) bonds, possess promising physiochemical and physiological properties with numerous potential applications. In this study, a novel levan-producing levansucrase was characterized from Brenneria goodwinii. The polysaccharide produced by the recombinant enzyme from sucrose was structurally determined to be levan-type fructan connected by β-(2, 6) linkages. The optimum pH was measured to be pH 6.0 for both sucrose hydrolysis and transfructosylation...
February 10, 2017: Carbohydrate Polymers
https://www.readbyqxmd.com/read/27940337/immobilization-of-levan-xylanase-nanohybrid-on-an-alginate-bead-improves-xylanase-stability-at-wide-ph-and-temperature
#10
Preethi Jampala, M Preethi, Swathy Ramanujam, B S Harish, Kiran Babu Uppuluri, Veerappan Anbazhagan
Despite the sustainable availability, levan, a fructose based natural polysaccharide has not received significant attention in the development of enzyme immobilization technology. Herein, we prepared levan-xylanase (LXy) nanohybrid and characterized by scanning electron microscopy, particle size analyzer and zeta potential. To prevent the enzyme leakage from the nanohybrid, LXy was immobilized onto an alginate beads (NaAlg). Immobilization yield was optimized using a statistical method, central composite design...
February 2017: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/27906857/obesity-and-chronic-obstructive-pulmonary-disease-recent-knowledge-and-future-directions
#11
Corrine Hanson, Tricia LeVan
PURPOSE OF REVIEW: Obesity has been shown to have a significant impact on lung diseases, including chronic obstructive pulmonary disease (COPD). The purpose of this review is to discuss the most recent findings regarding the association between obesity, COPD, and COPD-related outcomes. RECENT FINDINGS: Evidence indicates that obese patients with COPD may compose a unique disease phenotype who are more susceptible than their lean counterparts to environmental exposures...
March 2017: Current Opinion in Pulmonary Medicine
https://www.readbyqxmd.com/read/27885938/genomic-analysis-of-bacillus-subtilis-lytic-bacteriophage-%C3%AF-nit1-capable-of-obstructing-natto-fermentation-carrying-genes-for-the-capsule-lytic-soluble-enzymes-poly-%C3%AE-glutamate-hydrolase-and-levanase
#12
Tatsuro Ozaki, Naoki Abe, Keitarou Kimura, Atsuto Suzuki, Jun Kaneko
Bacillus subtilis strains including the fermented soybean (natto) starter produce capsular polymers consisting of poly-γ-glutamate and levan. Capsular polymers may protect the cells from phage infection. However, bacteriophage ϕNIT1 carries a γ-PGA hydrolase gene (pghP) that help it to counteract the host cell's protection strategy. ϕNIT had a linear double stranded DNA genome of 155,631-bp with a terminal redundancy of 5,103-bp, containing a gene encoding an active levan hydrolase. These capsule-lytic enzyme genes were located in the possible foreign gene cluster regions between central core and terminal redundant regions, and were expressed at the late phase of the phage lytic cycle...
January 2017: Bioscience, Biotechnology, and Biochemistry
https://www.readbyqxmd.com/read/27845256/prospective-motion-correction-in-functional-mri
#13
Maxim Zaitsev, Burak Akin, Pierre LeVan, Benjamin R Knowles
Due to the intrinsic low sensitivity of BOLD-fMRI long scanning is required. Subject motion during fMRI scans reduces statistical significance of the activation maps and increases the prevalence of false activations. Motion correction is therefore an essential tool for a successful fMRI data analysis. Retrospective motion correction techniques are now commonplace and are incorporated into a wide range of fMRI analysis toolboxes. These techniques are advantageous due to robustness, sequence independence and have minimal impact on the fMRI study setup...
November 11, 2016: NeuroImage
https://www.readbyqxmd.com/read/27779890/positive-negative-birefringence-in-multiferroic-layered-metasurfaces
#14
R Khomeriki, L Chotorlishvili, I Tralle, J Berakdar
We uncover and identify the regime for a magnetically and ferroelectrically controllable negative refraction of a light-traversing multiferroic, oxide-based metastructure consisting of alternating nanoscopic ferroelectric (SrTiO3) and ferromagnetic (Y3Fe2(FeO4)3, YIG) layers. We perform analytical and numerical simulations based on discretized, coupled equations for the self-consistent Maxwell/ferroelectric/ferromagnetic dynamics and obtain a biquadratic relation for the refractive index. Various scenarios of ordinary and negative refraction in different frequency ranges are analyzed and quantified by simple analytical formula that are confirmed by full-fledge numerical simulations...
November 9, 2016: Nano Letters
https://www.readbyqxmd.com/read/27765635/molecular-analysis-of-hybrid-neurofibroma-schwannoma-identifies-common-monosomy-22-and-%C3%AE-t-catenin-ctnna3-as-a-novel-candidate-tumor-suppressor
#15
Verena Stahn, Inga Nagel, Susan Fischer-Huchzermeyer, Florian Oyen, Reinhard Schneppenheim, Stefan Gesk, Axel Bohring, Levan Chikobava, Peter Young, Burkhard Gess, Mathias Werner, Volker Senner, Anja Harder
Neurofibromas and schwannomas are benign Schwann cell-derived peripheral nerve sheath tumors arising sporadically and within neurofibromatoses. Multiple tumors are a hallmark of neurofibromatosis type 1 (NF1) and type 2 (NF2) and schwannomatosis. Neurofibromas in NF1 and schwannomas in NF2 or schwannomatosis are defined by distinctive molecular hits. Among these, multiple hybrid neurofibromas/schwannomas may also appear, not yet being defined by a molecular background. We therefore performed molecular analysis of 22 hybrid neurofibromas/schwannomas using array comparative genomic hybridization, immunohistochemistry, quantitative RT-PCR, and functional analyses of cultured Schwann cells...
October 17, 2016: American Journal of Pathology
https://www.readbyqxmd.com/read/27763619/an-overview-of-laboratory-animal-science-in-the-nation-of-georgia
#16
Brett J Taylor, Karen Mulkijanyan, Levan Chitiashvili, Marika Ramishvili, Kakha Mchedlishvili
No abstract text is available yet for this article.
October 20, 2016: Lab Animal
https://www.readbyqxmd.com/read/27759919/a-synthesis-of-radial-growth-patterns-preceding-tree-mortality
#17
Maxime Cailleret, Steven Jansen, Elisabeth M R Robert, Lucía Desoto, Tuomas Aakala, Joseph A Antos, Barbara Beikircher, Christof Bigler, Harald Bugmann, Marco Caccianiga, Vojtěch Čada, J Julio Camarero, Paolo Cherubini, Hervé Cochard, Marie R Coyea, Katarina Čufar, Adrian J Das, Hendrik Davi, Sylvain Delzon, Michael Dorman, Guillermo Gea-Izquierdo, Sten Gillner, Laurel J Haavik, Henrik Hartmann, Ana-Maria Hereş, Kevin R Hultine, Pavel Janda, Jeffrey M Kane, Vyacheslav I Kharuk, Thomas Kitzberger, Tamir Klein, Koen Kramer, Frederic Lens, Tom Levanic, Juan Carlos Linares Calderon, Francisco Lloret, Raquel Lobo-Do-Vale, Fabio Lombardi, Rosana López Rodríguez, Harri Mäkinen, Stefan Mayr, Ilona Mészáros, Juha M Metsaranta, Francesco Minunno, Walter Oberhuber, Andreas Papadopoulos, Mikko Peltoniemi, Any Mary Petritan, Brigitte Rohner, Gabriel Sangüesa-Barreda, Dimitrios Sarris, Jeremy M Smith, Amanda B Stan, Frank Sterck, Dejan B Stojanović, Maria Laura Suarez, Miroslav Svoboda, Roberto Tognetti, José M Torres-Ruiz, Volodymyr Trotsiuk, Ricardo Villalba, Floor Vodde, Alana R Westwood, Peter H Wyckoff, Nikolay Zafirov, Jordi Martínez-Vilalta
Tree mortality is a key factor influencing forest functions and dynamics, but our understanding of the mechanisms leading to mortality and the associated changes in tree growth rates are still limited. We compiled a new pan-continental tree-ring width database from sites where both dead and living trees were sampled (2,970 dead and 4,224 living trees from 190 sites, including 36 species), and compared early and recent growth rates between trees that died and those that survived a given mortality event. We observed a decrease in radial growth before death in ca...
October 19, 2016: Global Change Biology
https://www.readbyqxmd.com/read/27753193/cellulose-production-activated-by-cyclic-di-gmp-through-bcsa-and-bcsz-is-a-virulence-factor-and-an-essential-determinant-of-the-three-dimensional-architectures-of-biofilms-formed-by-erwinia-amylovora-ea1189
#18
Luisa F Castiblanco, George W Sundin
Bacterial biofilms are multicellular aggregates encased in an extracellular matrix mainly composed of exopolysaccharides (EPSs), protein and nucleic acids, which determines the architecture of the biofilm. Erwinia amylovora Ea1189 forms a biofilm inside the xylem of its host, which results in vessel plugging and water transport impairment. The production of the EPSs amylovoran and levan is critical for the formation of a mature biofilm. In addition, cyclic dimeric GMP (c-di-GMP) has been reported to positively regulate amylovoran biosynthesis and biofilm formation in E...
October 18, 2016: Molecular Plant Pathology
https://www.readbyqxmd.com/read/27734288/optimization-of-levan-production-by-cold-active-bacillus-licheniformis-ant-179-and-fructooligosaccharide-synthesis-by-its-levansucrase
#19
Janifer Raj Xavier, Karna Venkata Ramana
Fructooligosaccharides (FOS) and levan attract much attention due to a wide range of applications in food technology and pharmaceutical and cosmetic industry. Bacillus licheniformis ANT 179, isolated from Antarctica soil, produced levansucrase and levan in a medium containing sucrose as carbon substrate. In this study, characterization of levansucrase and production of short-chain FOS and levan were investigated. Temperature and pH optimum of the enzyme were found to be 60 °C and pH 6.0, respectively. The optimization of fermentation conditions for levan production using sugarcane juice by response surface methodology (RSM) was carried out...
October 12, 2016: Applied Biochemistry and Biotechnology
https://www.readbyqxmd.com/read/27716345/dissection-of-exopolysaccharide-biosynthesis-in-kozakia-baliensis
#20
Julia U Brandt, Frank Jakob, Jürgen Behr, Andreas J Geissler, Rudi F Vogel
BACKGROUND: Acetic acid bacteria (AAB) are well known producers of commercially used exopolysaccharides, such as cellulose and levan. Kozakia (K.) baliensis is a relatively new member of AAB, which produces ultra-high molecular weight levan from sucrose. Throughout cultivation of two K. baliensis strains (DSM 14400, NBRC 16680) on sucrose-deficient media, we found that both strains still produce high amounts of mucous, water-soluble substances from mannitol and glycerol as (main) carbon sources...
October 4, 2016: Microbial Cell Factories
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