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https://www.readbyqxmd.com/read/28732036/an-accurate-coarse-grained-model-for-chitosan-polysaccharides-in-aqueous-solution
#1
Levan Tsereteli, Andrea Grafmüller
Computational models can provide detailed information about molecular conformations and interactions in solution, which is currently inaccessible by other means in many cases. Here we describe an efficient and precise coarse-grained model for long polysaccharides in aqueous solution at different physico-chemical conditions such as pH and ionic strength. The Model is carefully constructed based on all-atom simulations of small saccharides and metadynamics sampling of the dihedral angles in the glycosidic links, which represent the most flexible degrees of freedom of the polysaccharides...
2017: PloS One
https://www.readbyqxmd.com/read/28717996/patterns-of-oribatid-mite-species-diversity-testing-the-effects-of-elevation-area-and-sampling-effort
#2
Levan Mumladze, Maka Murvanidze, Mark Maraun
Elevational gradients in species diversity and species area relationships are two well established patterns that are not mutually exclusive in space and time. Elevation and area are both considered as good proxies to detect and characterize the patterns of species diversity distribution. However, such studies are hampered by the incomplete biodiversity data available for ecologists, which may affect the pattern perceptions. Using the large dataset of oribatid mite communities sampled in Georgia, we tested the effects of altitude and area on species distribution using various approaches, while explicitly considering the biases from sampling effort...
July 17, 2017: Experimental & Applied Acarology
https://www.readbyqxmd.com/read/28714842/molecular-and-biochemical-characteristics-of-the-inulosucrase-hugo-from-streptomyces-viridochromogenes-dsm40736-t%C3%A3-494
#3
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/28637539/laparoscopic-excision-of-remnant-gallbladder-after-subtotal-cholecystectomy
#4
Levan Tsamalaidze, Tariq Almerey, Lucio Pereira, Samantha Permenter, John A Stauffer
No abstract text is available yet for this article.
June 1, 2017: American Surgeon
https://www.readbyqxmd.com/read/28635269/reduction-potentials-of-fefe-hydrogenase-accessory-iron-sulfur-clusters-provide-insights-into-the-energetics-of-proton-reduction-catalysis
#5
Jacob H Artz, David W Mulder, Michael W Ratzloff, Carolyn E Lubner, Oleg A Zadvornyy, Axl X LeVan, S Garrett Williams, Michael W W Adams, Anne K Jones, Paul W King, John W Peters
An [FeFe]-hydrogenase from Clostridium pasteurianum, CpI, is a model system for biological H2 activation. In addition to the catalytic H-cluster, CpI contains four accessory iron-sulfur [FeS] clusters in a branched series that transfer electrons to and from the active site. In this work, potentiometric titrations have been employed in combination with electron paramagnetic resonance (EPR) spectroscopy at defined electrochemical potentials to gain insights into the role of the accessory clusters in catalysis...
July 6, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28602989/brachybacterium-sp-ch-kov3-isolated-from-an-oil-polluted-environment-a-new-producer-of-levan
#6
Aleksandra Djurić, Gordana Gojgić-Cvijović, Dragica Jakovljević, Branka Kekez, Jovana Stefanović Kojić, Maija-Liisa Mattinen, Inka Elina Harju, Miroslav M Vrvić, Vladimir P Beškoski
Various microorganisms isolated from polluted environments, such as Pseudomonas sp. and Micrococcus sp. can synthesize exopolysaccharides (EPSs) which are natural, non-toxic and biodegradable polymers. EPSs play a key role in protection of microbial cells under various external influences. For humans, these substances have potential use in many industries. EPSs can be applied as a flavor or a fragrance carrier, an emulsifier, a stabilizer, a prebiotic, an antioxidant or an antitumor agent. In this study, we characterized an environmental microorganism that produces EPS, optimized EPS production by this strain and characterized the EPS produced...
June 8, 2017: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/28595337/response-to-the-association-of-progressive-tension-sutures-and-drains-seems-to-decrease-the-drainage-output-and-seroma-formation-in-abdominoplasty
#7
Samer Jabbour, Rani Makhoul, Cyril Awaida, Philippe Levan, Taliah Schmitt, Marwan Nasr
No abstract text is available yet for this article.
June 8, 2017: Aesthetic Surgery Journal
https://www.readbyqxmd.com/read/28588563/insight-into-potential-probiotic-markers-predicted-in-lactobacillus-pentosus-mp-10-genome-sequence
#8
Hikmate Abriouel, Beatriz Pérez Montoro, Carlos S Casimiro-Soriguer, Antonio J Pérez Pulido, Charles W Knapp, Natacha Caballero Gómez, Sonia Castillo-Gutiérrez, María D Estudillo-Martínez, Antonio Gálvez, Nabil Benomar
Lactobacillus pentosus MP-10 is a potential probiotic lactic acid bacterium originally isolated from naturally fermented Aloreña green table olives. The entire genome sequence was annotated to in silico analyze the molecular mechanisms involved in the adaptation of L. pentosus MP-10 to the human gastrointestinal tract (GIT), such as carbohydrate metabolism (related with prebiotic utilization) and the proteins involved in bacteria-host interactions. We predicted an arsenal of genes coding for carbohydrate-modifying enzymes to modify oligo- and polysaccharides, such as glycoside hydrolases, glycoside transferases, and isomerases, and other enzymes involved in complex carbohydrate metabolism especially starch, raffinose, and levan...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28575294/impaired-coordination-of-nucleophile-and-increased-hydrophobicity-in-the-1-subsite-shift-levansucrase-activity-towards-transfructosylation
#9
Maria Elena Ortiz-Soto, Christian Possiel, Julian Görl, Andreas Vogel, Ramona Schmiedel, Jürgen Seibel
Bacterial levansucrases produce β(2,6)-linked levan-type polysaccharides using sucrose or sucrose analogues as donor/acceptor substrates. However, the dominant reaction of Bacillus megaterium levansucrase (Bm-LS) is hydrolysis. Single domain levansucrases from Gram-positive bacteria display a wide substrate-binding pocket with open access to water, challenging engineering for transfructosylation-efficient enzymes. We pursued a shift in reaction specificity by either modifying the water distribution in the active site or the coordination of the catalytic acid/base (E352) and the nucleophile (D95), thus affecting the fructosyl-transfer rate and allowing acceptors other than water to occupy the active site...
May 30, 2017: Glycobiology
https://www.readbyqxmd.com/read/28554522/engineering-aspects-of-microbial-exopolysaccharide-production
#10
Filomena Freitas, Cristiana A V Torres, Maria A M Reis
Although the ability to secrete exopolysaccharides (EPS) is widespread among microorganisms, only a few bacterial (e.g. xanthan, levan, dextran) and fungal (e.g. pullulan) EPS have reached full commercialization. During the last years, other microbial EPS producers have been the subject of extensive research, including endophytes, extremophiles, microalgae and Cyanobacteria, as well as mixed microbial consortia. Those studies have demonstrated the great potential of such microbial systems to generate biopolymers with novel chemical structures and distinctive functional properties...
May 18, 2017: Bioresource Technology
https://www.readbyqxmd.com/read/28535808/effect-of-bacteria-type-and-sucrose-concentration-on-levan-yield-and-its-molecular-weight
#11
Álvaro González-Garcinuño, Antonio Tabernero, José Mª Sánchez-Álvarez, Miguel A Galán, Eva M Martin Del Valle
BACKGROUND: Levan has been traditionally produced from microorganism. However, there is a continuous effort in looking for new strains that improve levan production yield and uses alternative sugar sources for growth. Despite having a wide range of data about levan yield, there are not papers which allow controlling molecular weight, and that plays an essential role for further applications. RESULTS: The effect of the sucrose concentration on levan yield (and its molecular weight) from Bacillus atrophaeus and Acinetobacter nectaris (Gram positive and Gram negative respectively) was studied in this work...
May 23, 2017: Microbial Cell Factories
https://www.readbyqxmd.com/read/28522999/fermentation-ph-modulates-the-size-distributions-and-functional-properties-of-gluconobacter-albidus-tmw-2-1191-levan
#12
Tharalinee Ua-Arak, Frank Jakob, Rudi F Vogel
Bacterial levan has gained an increasing interest over the last decades due to its unique characteristics and multiple possible applications. Levan and other exopolysaccharides (EPSs) production are usually optimized to obtain the highest concentration or yield while a possible change of the molecular size and mass during the production process is mostly neglected. In this study, the molar mass and radius of levan samples were monitored during fermentations with the food-grade, levan-producing acetic acid bacterium Gluconobacter (G...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28464843/immunohistochemical-evaluation-of-epithelial-ovarian-carcinomas-identifies-three-different-expression-patterns-of-the-mx35-antigen-napi2b
#13
Kristina Levan, Matin Mehryar, Constantina Mateoiu, Per Albertsson, Tom Bäck, Karin Sundfeldt
BACKGROUND: To characterize the expression of the membrane transporter NaPi2b and antigen targeted by the MX35 antibody in ovarian tumor samples. The current interest to develop monoclonal antibody based therapy of ovarian cancer by targeting NaPi2b emphasizes the need for detailed knowledge and characterization of the expression pattern of this protein. For the majority of patients with ovarian carcinoma the risk of being diagnosed in late stages with extensive loco-regional spread disease is substantial, which stresses the need to develop improved therapeutic agents...
May 2, 2017: BMC Cancer
https://www.readbyqxmd.com/read/28449124/labia-majora-augmentation-a-systematic-review-of-the-literature
#14
Samer Jabbour, Elio Kechichian, Barbara Hersant, Philippe Levan, Lena El Hachem, Warren Noel, Marwan Nasr
Background: Currently, there is no standardized approach for labia majora augmentation and controversies still exist regarding this subject. Objectives: This systematic review aimed to assess the evidence in the literature regarding labia majora augmentation. Methods: On November 20, 2016, we conducted an online search of published articles in the Medline, Embase, and Cochrane databases. All articles describing labia majora augmentation were included in this review...
April 26, 2017: Aesthetic Surgery Journal
https://www.readbyqxmd.com/read/28421913/type-vi-secretion-systems-of-erwinia-amylovora-contribute-to-bacterial-competition-virulence-and-exopolysaccharide-production
#15
Yanli Tian, Yuqiang Zhao, Linye Shi, Zhongli Cui, Baishi Hu, Youfu Zhao
The type VI secretion system (T6SS) plays a major role in mediating interbacterial competition and might contribute to virulence in plant pathogenic bacteria. However, the role of T6SS in Erwinia amylovora remains unknown. In this study, 33 deletion mutants within three T6SS clusters were generated in E. amylovora strain NCPPB1665. Our results showed that all 33 mutants displayed reduced antibacterial activities against Escherichia coli as compared with that of the wild-type (WT) strain, indicating that Erwinia amylovora T6SS are functional...
June 2017: Phytopathology
https://www.readbyqxmd.com/read/28412340/levan-promotes-antiproliferative-and-pro-apoptotic-effects-in-mcf-7-breast-cancer-cells-mediated-by-oxidative-stress
#16
Eveline A I F Queiroz, Zuleica B Fortes, Mário A A da Cunha, Hande Kazak Sarilmiser, Aneli M Barbosa Dekker, Ebru Toksoy Öner, Robert F H Dekker, Neelam Khaper
Exopolysaccharides are high-valued bio-products produced by various microbial species and have been described to possess biological response modifying activities. These bio-products have been effective as therapeutic agents in various human disease conditions. The objective of this study was to examine the effects of levan (a (2→6)-β-d-fructan) produced on sucrose by the halophilic bacterium, Halomonas smyrnensis AAD6(T), in human breast cancer MCF-7 cells. MCF-7 cells were exposed to levan for 24 and 48h...
September 2017: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/28400025/influence-of-levan-producing-acetic-acid-bacteria-on-buckwheat-sourdough-breads
#17
Tharalinee Ua-Arak, Frank Jakob, Rudi F Vogel
Buckwheat sourdoughs supplemented with molasses as natural sucrose source were fermented with levan-producing Gluconobacter (G.) albidus TMW 2.1191 and Kozakia (K.) baliensis NBRC 16680. Cell growth, concomitant levan and low-molecular-weight metabolite production were monitored. Sourdough breads were prepared with different sourdoughs from both strains (24, 30 and 48 h fermentation, respectively) and analyzed with respect to bread volume, crumb hardness and sensory characteristics. During fermentation, levan, acetic and gluconic acids were increasingly produced, while spontaneously co-growing lactic acid bacteria additionally formed acetic and lactic acids...
August 2017: Food Microbiology
https://www.readbyqxmd.com/read/28398515/gluteal-implants-versus-autologous-flaps-in-patients-with-postbariatric-surgery-weight-loss-a-prospective-comparative-study-of-3-dimensional-gluteal-projection-after-lower-body-lift
#18
Philippe Levan, Samer Bassilios Habre
Background: Deformities and excess skin resulting from massive weight loss are corrected with circumferential lower body lift (LBL). The gluteal area is frequently flattened due to aggressive skin excision during LBL. Gluteal implants can circumvent this problem. Objectives: We aimed to objectively evaluate the outcomes of gluteal augmentation with implants versus flap surgery performed simultaneously with LBL. Methods: Between January 2014 and June 2015, twenty-seven patients underwent LBL with gluteal implants (10 patients), flaps (14 patients), or no gluteal augmentation (3 patients) in our hospital...
April 7, 2017: Aesthetic Surgery Journal
https://www.readbyqxmd.com/read/28363576/novel-levan-and-pnipa-temperature-sensitive-hydrogels-for-5-asa-controlled-release
#19
Asila Osman, Ebru Toksoy Oner, Mehmet S Eroglu
Levan based cross-linker was successfully synthesized and used to prepare a series of more biocompatible and temperature responsive levan/N-isopropyl acrylamide (levan/pNIPA) hydrogels by redox polymerization at room temperature. Volume phase transition temperature (VPTT) of the hydrogels were precisely determined by derivative differential scanning calorimetry (DDSC). Incorporation of levan into the pNIPA hydrogel increased the VPTT from 32.8°C to 35.09°C, approaching to body temperature. Swelling behavior and 5-aminosalicylic acid (5-ASA) release of the hydrogels were found to vary significantly with temperature and composition...
June 1, 2017: Carbohydrate Polymers
https://www.readbyqxmd.com/read/28350252/long-term-cognitive-and-neuroanatomical-stability-in-patients-with-anoxic-amnesia-a-case-report
#20
Kacie L Wright, C Brock Kirwan, Shawn D Gale, Ashley J Levan, Ramona O Hopkins
BACKGROUND: Anoxia can result in selective hippocampal damage with associated impairments in declarative memory. Whilst memory impairments and brain structures are thought to be stable, there are little data regarding the effects of ageing or change over time in patients with amnesia from anoxic brain injury. METHODS: To assess change over time, we compared structural magnetic resonance imaging (MRI) with data obtained over ten years previously in two well-characterized patients with amnesia (JRW and RS) who experienced an anoxic brain injury...
March 28, 2017: Brain Injury: [BI]
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