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https://www.readbyqxmd.com/read/28550062/engineering-of-a-hyperthermophilic-archaeon-thermococcus-kodakarensis-that-displays-chitin-dependent-hydrogen-production
#1
Mehwish Aslam, Ayumi Horiuchi, Jan-Robert Simons, Savyasachee Jha, Masahiro Yamada, Toru Odani, Rikako Fujimoto, Yasuyuki Yamamoto, Ryoma Gunji, Tadayuki Imanaka, Tamotsu Kanai, Haruyuki Atomi
Thermococcus kodakarensis is a hyperthermophilic archaeon that harbors a complete set of genes for chitin degradation to fructose 6-phosphate. However, wild-type T. kodakarensis KOD1 does not display growth on chitin. In this study, we developed a T. kodakarensis strain that can grow on chitin via genetic and adaptive engineering. First, a chitinase overproduction strain (KC01) was constructed by replacing the chitinase gene promoter with a strong promoter from the cell-surface glycoprotein gene, resulting in increased degradation of swollen chitin and accumulation of N-, N'-diacetylchitobiose in the medium...
May 26, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28549840/phosphatidylinositol-4-5-bisphosphate-mediated-pathophysiological-effect-of-hiv-1-tat-protein
#2
REVIEW
Bruno Beaumelle, Petra Tóth, Olfat A Malak, Christophe Chopard, Gildas Loussouarn, Nicolas Vitale
Human immunodeficiency virus (HIV)-infected cells actively release the transcriptional activator (Tat) viral protein that is required for efficient HIV gene transcription. Extracellular Tat is able to enter uninfected cells. We recently reported that internalized Tat escapes endosomes to reach the cytosol and is then recruited to the plasma membrane by phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P2). As a consequence, Tat strongly impairs different critical cellular functions in several cell types. Here we will review recent evidences showing that Tat, by affecting the interaction of key cellular effectors with PtdIns(4,5)P2, blocks exocytosis from neuroendocrine cells, perturbs the synaptic vesicle exo-endocytosis cycle, prevents efficient phagocytosis by macrophages, and alters potassium channel activity in cardiac cells...
May 23, 2017: Biochimie
https://www.readbyqxmd.com/read/28548155/silver-mediated-radical-5-exo-dig-cyclization-of-2-alkynylbenzonitriles-synthesis-of-phosphinylated-1-indenones
#3
Xiao-Tong Zhu, Qi Zhao, Feng Liu, Ai-Fang Wang, Pei-Jun Cai, Wen-Juan Hao, Shu-Jiang Tu, Bo Jiang
A new silver-mediated 5-exo-dig cyclization of 2-alkynylbenzonitriles with disubstituted phosphine oxide and H2O has been developed. The reaction enables multiple bond-forming events including C-P, C-C and C-O bonds under atmospheric conditions, leading to the concise and direct formation of 28 examples of phosphorus-containing 1-indenones with generally good yields.
May 26, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/28546840/nucleophilic-and-electrophilic-cyclization-of-n-alkyne-substituted-pyrrole-derivatives-synthesis-of-pyrrolopyrazinone-pyrrolotriazinone-and-pyrrolooxazinone-moieties
#4
Işıl Yenice, Sinan Basceken, Metin Balci
Intramolecular nucleophilic and electrophilic cyclization of N-alkyne-substituted pyrrole esters is described. Efficient routes towards the synthesis of pyrrolopyrazinone, pyrrolotriazinone and pyrrolooxazinone have been developed. First, N-alkyne-substituted pyrrole ester derivatives were synthesized. Introduction of various substituents into the alkyne functionality was accomplished by a copper-catalyzed cross-coupling reaction. Nucleophilic cyclization of N-alkyne-substituted methyl 1H-pyrrole-2-carboxylates with hydrazine afforded the 6-exo-dig/6-endo-dig cyclization products depending on the electronic nature of the substituents attached to the alkyne...
2017: Beilstein Journal of Organic Chemistry
https://www.readbyqxmd.com/read/28536001/membrane-shaping-by-actin-and-myosin-during-regulated-exocytosis
#5
REVIEW
Andreas Papadopulos
The cortical actin network in neurosecretory cells is a dense mesh of actin filaments underlying the plasma membrane. Interaction of actomyosin with vesicular membranes or the plasma membrane is vital for tethering, retention, transport as well as fusion and fission of exo- and endocytic membrane structures. During regulated exocytosis the cortical actin network undergoes dramatic changes in morphology to accommodate vesicle docking, fusion and replenishment. Most of these processes involve plasma membrane Phosphoinositides (PIP) and investigating the interactions between the actin cortex and secretory structures has become a hotbed for research in recent years...
May 20, 2017: Molecular and Cellular Neurosciences
https://www.readbyqxmd.com/read/28534923/divergent-syntheses-of-iodinated-isobenzofuranones-and-isochromenones-by-iodolactonization-of-2-alkynylbenzoic-acids-in-ionic-liquids
#6
Raffaella Mancuso, Christian C Pomelli, Francesco Malafronte, Asif Maner, Nadia Marino, Cinzia Chiappe, Bartolo Gabriele
The regiochemical outcome of the iodolactonization of 2-alkynylbenzoic acids, carried out at 100 °C in ionic liquids (ILs) as unconventional solvents and with molecular iodine as the iodine source, in the absence of external bases, was found to be strongly dependent on the nature of the IL medium. In particular, while the use of N-ethyl-N-methylmorpholinium dicyanamide (Mor1,2N(CN)2) promoted the stereoselective formation of (E)-3-(iodomethylene)isobenzofuran-1(3H)-ones, through an anti-5-exo-dig cyclization route, the use of 1-ethyl-3-methylimidazolium ethyl sulfate (EmimEtSO4) tended to favor the 6-endo-dig cyclization mode, with preferential or selective formation of 4-iodo-1H-isochromen-1-ones...
May 23, 2017: Organic & Biomolecular Chemistry
https://www.readbyqxmd.com/read/28533382/interplay-of-catalysis-fidelity-threading-and-processivity-in-the-exo-and-endonucleolytic-reactions-of-human-exonuclease-i
#7
Yuqian Shi, Homme W Hellinga, Lorena S Beese
Human exonuclease 1 (hExo1) is a member of the RAD2/XPG structure-specific 5'-nuclease superfamily. Its dominant, processive 5'-3' exonuclease and secondary 5'-flap endonuclease activities participate in various DNA repair, recombination, and replication processes. A single active site processes both recessed ends and 5'-flap substrates. By initiating enzyme reactions in crystals, we have trapped hExo1 reaction intermediates that reveal structures of these substrates before and after their exo- and endonucleolytic cleavage, as well as structures of uncleaved, unthreaded, and partially threaded 5' flaps...
May 22, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28531338/placental-exosomes-as-early-biomarker-of-preeclampsia-potential-role-of-exosomal-micrornas-across-gestation
#8
Carlos Salomon, Dominic Guanzon, Katherin Scholz-Romero, Sherri Longo, Paula Correa, Sebastian E Illanes, Gregory E Rice
Context: There is a need to develop strategies for early prediction of patients who will develop preeclampsia (PE), in order to establish preventive strategies to reduce the prevalence and severity of the disease and their associated complications. Objective: The objective of this study was to investigate whether exosomes and their microRNA cargo present in maternal circulation can be used as early biomarker for PE. Design, Setting, Patients, and Interventions: A retrospective stratified study design was used to quantify total exosomes (EXO) and placenta-derived exosomes (PdE) present in maternal plasma of normal (n=32 per time point) and PE (n=15 per time point) pregnancies...
May 22, 2017: Journal of Clinical Endocrinology and Metabolism
https://www.readbyqxmd.com/read/28529446/synthesis-of-chiral-tetrahydrofurans-and-pyrrolidines-by-visible-light-mediated-deoxygenation
#9
Daniel Rackl, Viktor Kais, Eugen Lutsker, And Oliver Reiser
The synthesis of chiral tetrahydrofurans and pyrrolidines starting from 1,2-diols or β-amino alcohols, respectively, by visible-light-mediated deoxygenation is described. Easily accessible monoallylated/propargylated substrates were activated either as inexpensive ethyl oxalates or as recyclable 3,5-bis(trifluoromethyl)benzoates to generate alkyl radicals suitable for 5-exo-trig/5-exo-dig cyclizations under visible-light irradiation.
April 18, 2017: European Journal of Organic Chemistry
https://www.readbyqxmd.com/read/28525849/novel-photoelectrochemical-immunosensor-for-disease-related-protein-assisted-by-hemin-g-quadruplex-based-dnazyme-on-gold-nanoparticles-to-enhance-cathodic-photocurrent-on-p-cubi2o4-semiconductor
#10
Shuzhen Lv, Kangyao Zhang, Zhenzhen Lin, Dianping Tang
A novel p-type semiconductor material (p-CuBi2O4) is designed for the construction of split-type photoelectrochemical (PEC) immunosensor for alpha-fetoprotein (AFP) with the hemin assistant to enhance the cathodic photocurrent. Initially, the photocathode of PEC immunosensor is fabricated by p-CuBi2O4 on a layer of gold nanoparticles (AuNPs, as a front contact of p-CuBi2O4) to enhance the efficiency of charge separation. In the presence of target AFP, a sandwich-type immunoreaction was carried out in capture antibody-coated microplate by using detection antibody and hemin-based G-quadruplex (labeled on the AuNP) as the signal probe...
May 13, 2017: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/28523855/double-activation-catalysis-for-%C3%AE-%C3%A2-alkylidene-cyclic-enones-with-chiral-amines-and-thiols
#11
Ying-Chun Chen, Zhou-Xiang Wang, Zhi Zhou, Wei Xiao, Qin Ouyang, Wei Du
Cooperative catalysis has contributed greatly to the progress of asymmetric synthesis. Nevertheless, the double activation catalysis has been less explored, especially in a covalently tethered pattern. Here we present a double activation strategy for α´-alkylidene cyclic enone substrates with a chiral primary amine and 2-mercaptobenzoic acid, through regio- and chemoselective additions to generate the complex interrupted iminium ion species. Significantly enhanced reactivity and enantioselectivity have been observed in the β-regioselective Michael addition and Friedel-Crafts alkylation reactions with malononitriles and indoles, respectively, producing a spectrum of chiral cyclic adducts with an exo-alkylidene group...
May 18, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28521209/use-of-solid-digestate-for-lignocellulolytic-enzymes-production-through-submerged-fungal-fermentation
#12
Alida Musatti, Elena Ficara, Chiara Mapelli, Cecilia Sambusiti, Manuela Rollini
Studies were performed on the use of the solid fraction of digestate (D) for the production of lignocellulolytic enzymes (endo- and exo-glucanase, xylanase, β-glucosidase and laccase) by fungi, in comparison with wheat straw (benchmark) (W). To date, this is the first report on the use of such an inexpensive substrate in a liquid environment. Submerged instead of solid state fermentation was applied to overcome pH inhibition and increase surface accessibility. A total of 21 fungal strains were tested: the most performing ones were Irpex lacteus DSM1183 for both β-glucosidase (52 IU/g with D, + 400% compared to W) and endo-glucanase (236 IU/g with D, + 470% compared to W), Schizophyllum commune CBS30132 for xylanase (715 IU/g with W, + 145% compared to D) and Pleurotus ostreatus ATCC96997 for laccase (124 IU/g with D, +230% compared to D)...
May 15, 2017: Journal of Environmental Management
https://www.readbyqxmd.com/read/28521074/metal-free-hydroalkoxylation-formal-4-2-cycloaddition-cascade-for-the-synthesis-of-ketals
#13
Santosh J Gharpure, Santosh Kumar Nanda, Padmaja Padmaja, Yogesh Gangaram Shelke
A transition metal free, acid promoted cascade hydroalkoxylation-formal [4+2] cycloaddition of various alkynols with salicylaldehyde is demonstrated for the synthesis of tetrahydrofurano/pyrano-chromenes and spiroketals. In general, alkynols underwent hydroalkoxylations in an endo-dig manner when internal alkynes were used to furnish the heteroannular ketals, whereas terminal alkynes proceeded in an exo-dig fashion leading to spiroketals. The study revealed that intramolecular hydroalkoxylation of alkynols is a preferred path over a generation of oxocarbenium ion formation when coupling partner is salicylaldehyde...
May 18, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28514926/trunk-muscle-activity-patterns-and-motion-patterns-of-patients-with-motor-complete-spinal-cord-injury-at-t8-and-t10-walking-with-different-un-powered-exoskeletons
#14
Xinyu Guan, Shengzheng Kuai, Linhong Ji, Rencheng Wang, Run Ji
OBJECTIVE: The aim of this study was to explore how neurological injured levels of spinal cord affect the performance of patients walking with different un-powered exoskeletons. STUDY DESIGN: Case series observational study. SETTING: Gait and Motion Analysis Laboratory at the National Research Center Rehabilitation Technical Aids. METHODS: Electromyography and motion data from two subjects with complete spinal cord injury at T10 and T8 walking with un-powered exoskeletons were collected simultaneously...
May 17, 2017: Journal of Spinal Cord Medicine
https://www.readbyqxmd.com/read/28504798/a-vacuum-ultraviolet-photoionization-study-on-high-temperature-decomposition-of-jp-10-exo-tetrahydrodicyclopentadiene
#15
Long Zhao, Tao Yang, Ralf I Kaiser, Tyler P Troy, Bo Xu, Musahid Ahmed, Juan Alarcon, Daniel Belisario-Lara, Alexander M Mebel, Yan Zhang, Chuangchuang Cao, Jiabiao Zou
Two sets of experiments were performed to unravel the high-temperature pyrolysis of tricyclo[5.2.1.0(2,6)] decane (JP-10) exploiting high-temperature reactors over a temperature range of 1100 K to 1600 K, Advanced Light Source (ALS), and 927 K to 1083 K, National Synchrotron Radiation Laboratory (NSRL), with residence times of a few tens of microseconds (ALS) to typically 144 ms (NSRL). The products were identified in situ in supersonic molecular beams via single photon vacuum ultraviolet (VUV) photoionization coupled with mass spectroscopic detection in a reflectron time-of-flight mass spectrometer (ReTOF)...
May 15, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28502854/characterization-of-a-bi-functional-cellulase-produced-by-a-gut-bacterial-resident-of-rosaceae-branch-borer-beetle-osphranteria-coerulescens-coleoptera-cerambycidae
#16
Atousa Hatefi, Ali Makhdoumi, Ahmad Asoodeh, Omid Mirshamsi
A cellulolytic bacterium was obtained from the digestive tract of Osphranteria coerulescens. The breakdown of woody and cellulosic substances by this insect may be relative in part to its symbiont bacteria. Under optimal cultural conditions the novel isolate produced 5.35U/ml cellulase after 72h. The enzyme was purified to 36 fold with a 0.59% yield and showed a specific activity of 9.0U/mg. It presented its maximum activity at 60°C and pH 5, while it was stable in a wide range of temperature from 20 to 60°C and pH from 5 to 10...
May 11, 2017: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/28496954/sexual-risk-behaviors-constructed-in-iranian-women-s-life-with-substance-use-disorders-a-new-implication-of-human-ecological-theory
#17
Mansoureh Jamshidimanesh, Seyed Abbas Mousavi, Effat Merghati-Khoei, Mohammad Hassan Emamian, Afsaneh Keramat
BACKGROUND: Drug abuse is one of the important variables influencing protective sexual behavior. The objective of this study was to explore how risky sexual behaviors develop in drug abusing women using human ecological theory. METHODS: In this study, we used a descriptive exploratory approach. The participants were 32 drug abusing women from two of the selected drop-in centers (DICs) in south Tehran, Iran, where we could have access to a vast number of female drug users...
July 2016: Addiction & Health
https://www.readbyqxmd.com/read/28494242/pseudomonas-aeruginosa-effector-exos-inhibits-ros-production-in-human-neutrophils
#18
Chairut Vareechon, Stephanie Elizabeth Zmina, Mausita Karmakar, Eric Pearlman, Arne Rietsch
Neutrophils are the first line of defense against bacterial infections, and the generation of reactive oxygen species is a key part of their arsenal. Pathogens use detoxification systems to avoid the bactericidal effects of reactive oxygen species. Here we demonstrate that the Gram-negative pathogen Pseudomonas aeruginosa is susceptible to reactive oxygen species but actively blocks the reactive oxygen species burst using two type III secreted effector proteins, ExoS and ExoT. ExoS ADP-ribosylates Ras and prevents it from interacting with and activating phosphoinositol-3-kinase (PI3K), which is required to stimulate the phagocytic NADPH-oxidase that generates reactive oxygen species...
May 10, 2017: Cell Host & Microbe
https://www.readbyqxmd.com/read/28493076/extracellular-vesicles-regulate-the-human-osteoclastogenesis-divergent-roles-in-discrete-inflammatory-arthropathies
#19
Nikolett Marton, Orsolya Tünde Kovács, Eszter Baricza, Ágnes Kittel, Dávid Győri, Attila Mócsai, Florian M P Meier, Carl S Goodyear, Iain B McInnes, Edit I Buzás, György Nagy
OBJECTIVE: Extracellular vesicles (EVs) are subcellular signalosomes. Although characteristic EV production is associated with numerous physiological and pathological conditions, the effect of blood-derived EVs on bone homeostasis is unknown. Herein we evaluated the role of circulating EVs on human osteoclastogenesis. METHODS: Blood samples from healthy volunteers, rheumatoid arthritis (RA) and psoriatic arthritis (PsA) patients were collected. Size-based EV sub-fractions were isolated by gravity-driven filtration and differential centrifugation...
May 10, 2017: Cellular and Molecular Life Sciences: CMLS
https://www.readbyqxmd.com/read/28485736/on-the-enzymatic-incorporation-of-an-imidazole-nucleotide-into-dna
#20
Pascal Röthlisberger, Fabienne Levi-Acobas, Ivo Sarac, Philippe Marlière, Piet Herdewijn, Marcel Hollenstein
The expansion of the genetic alphabet with an additional, artificial base pair is of high relevance for numerous applications in synthetic biology. The enzymatic construction of metal base pairs is an alluring strategy that would ensure orthogonality to canonical nucleic acids. So far, very little is known on the enzymatic fabrication of metal base pairs. Here, we report on the synthesis and the enzymatic incorporation of an imidazole nucleotide into DNA. The imidazole nucleotide dIm is known to form highly stable dIm-Ag(+)-dIm artificial base pairs that cause minimal structural perturbation of DNA duplexes and was considered to be an ideal candidate for the enzymatic construction of metal base pairs...
May 23, 2017: Organic & Biomolecular Chemistry
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