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https://www.readbyqxmd.com/read/28635269/the-reduction-potentials-of-fefe-hydrogenase-accessory-iron-sulfur-clusters-provide-insights-into-the-energetics-of-proton-reduction-catalysis
#1
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...
June 21, 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
#2
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
#3
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
#4
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
#5
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
#6
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
#7
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
#8
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
#9
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
#10
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
#11
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
#12
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...
April 12, 2017: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/28400025/influence-of-levan-producing-acetic-acid-bacteria-on-buckwheat-sourdough-breads
#13
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
#14
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
#15
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
#16
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]
https://www.readbyqxmd.com/read/28302109/interaction-of-cd14-haplotypes-and-soluble-cd14-on-pulmonary-function-in-agricultural-workers
#17
Tricia D LeVan, Lynette M Smith, Art J Heires, Ted R Mikuls, Jane L Meza, Lisa A Weissenburger-Moser, Debra J Romberger
BACKGROUND: Agricultural environments are contaminated with organic dusts containing bacterial components. Chronic inhalation of organic dusts is implicated in respiratory diseases. CD14 is a critical receptor for gram-negative lipopolysaccharide; however, its association with respiratory disease among agricultural workers is unknown. The objective of this study was to determine if serum soluble CD14 (sCD14) levels are associated with lung function among agricultural workers and if this association is modified by genetic variants in CD14...
March 16, 2017: Respiratory Research
https://www.readbyqxmd.com/read/28274423/a-novel-two-step-enzymatic-synthesis-of-blastose-a-%C3%AE-d-fructofuranosyl-2%C3%A2-6-d-glucopyranose-sucrose-analogue
#18
Alfonso Miranda-Molina, Edmundo Castillo, Agustin Lopez Munguia
Blastose, a natural disaccharide found in honey, is usually found as a byproduct of fructo-oligosaccharide synthesis from sucrose with fructosyltransferases. In this study, we describe a novel two-step biosynthetic route to obtain blastose, designed from a detailed observation of B. subtilis levansucrase (SacB) acceptor structural requirements for fructosylation. The strategy consisted first in the synthesis of the trisaccharide O-β-d-Fruf-(2↔6)-O-α-d-Glcp-(1↔1)-α-d-Glcp, through a regioselective β-d-transfructosylation of trehalose (Tre) which acts as acceptor in a reaction catalyzed by SacB using sucrose or levan as fructosyl donor...
July 15, 2017: Food Chemistry
https://www.readbyqxmd.com/read/28271385/possible-correlation-between-levansucrase-production-and-probiotic-activity-of-bacillus-sp-isolated-from-honey-and-honey-bee
#19
Abdelhamid A Hamdy, Nouran A Elattal, Magdy A Amin, Amal E Ali, Nahla M Mansour, Ghada E A Awad, Hassan M Awad, Mona A Esawy
Five bacterial isolates from honey and bee gut were selected based on their high levansucrase activity and levan yield which were strongly positively correlated. All isolates showed good tolerance to temperature up to 70 °C, to NaCl up to 3 M and to 0.1% H2O2. They maintained over 59 and 64% survival at pH 9.0 and 2.0 respectively, but showed varying tolerance to 0.1% bile salts and pancreatic enzymes. Most isolates were susceptible to widely used antibiotics, but demonstrated diverse antimicrobial activity...
April 2017: World Journal of Microbiology & Biotechnology
https://www.readbyqxmd.com/read/28197690/improvement-of-levan-production-in-bacillus-amyloliquefaciens-through-metabolic-optimization-of-regulatory-elements
#20
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
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