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https://www.readbyqxmd.com/read/29777686/molecular-interactions-between-geobacter-sulfurreducens-triheme-cytochromes-and-the-redox-active-analogue-for-humic-substances
#1
Joana M Dantas, Marisa R Ferreira, Teresa Catarino, Oleksandr Kokhan, P Raj Pokkuluri, Carlos A Salgueiro
The bacterium Geobacter sulfurreducens can transfer electrons to the quinone moieties of humic substances or to anthraquinone-2,6-disulfonate (AQDS), a model for the humic acids. The reduced form of AQDS (AH2 QDS) can also be used as energy source G. sulfurreducens. Such bi-directional utilization of humic substances confers competitive advantages to these bacteria in Fe(III) enriched environments. Previous studies have shown that the triheme cytochrome PpcA from G. sulfurreducens has a bi-functional behavior toward the humic substance analogue...
May 16, 2018: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/29777624/characterisation-of-a-putative-glutamate-5-kinase-from-leishmania-donovani
#2
Natasha Sienkiewicz, Han B Ong, Alan H Fairlamb
Previous metabolic studies have demonstrated that leishmania parasites are able to synthesise proline from glutamic acid and threonine from aspartic acid. The first committed step in both biosynthetic pathways involves an amino acid kinase, either a glutamate 5-kinase (EC 2.7.2.11) or an aspartokinase (EC 2.7.2.4). Bioinformatic analysis of multiple leishmania genomes identifies a single amino-acid-kinase gene (LdBPK 262740.1) variously annotated as either a putative glutamate or aspartate kinase. To establish the catalytic function of this Leishmania donovani gene product, we have determined the physical and kinetic properties of the recombinant enzyme purified from Escherichia coli...
May 19, 2018: FEBS Journal
https://www.readbyqxmd.com/read/29777512/discovery-of-an-acidic-thermostable-and-highly-nadp-dependent-formate-dehydrogenase-from-lactobacillus-buchneri-nrrl-b-30929
#3
Saadet Alpdağtaş, Sevil Yücel, Handan Açelya Kapkaç, Siqing Liu, Barış Binay
OBJECTIVES: To identify a robust NADP+ dependent formate dehydrogenase from Lactobacillus buchneri NRRL B-30929 (LbFDH) with unique biochemical properties. RESULTS: A new NADP+ dependent formate dehydrogenase gene (fdh) was cloned from genomic DNA of L. buchneri NRRL B-30929. The recombinant construct was expressed in Escherichia coli BL21(DE3) with 6 × histidine at the C-terminus and the purified protein obtained as a single band of approx. 44 kDa on SDS-PAGE and 90 kDa on native-PAGE...
May 18, 2018: Biotechnology Letters
https://www.readbyqxmd.com/read/29777455/combined-preoperative-albi-and-fib-4-is-associated-with-recurrence-of-hepatocellular-carcinoma-after-curative-hepatectomy
#4
Rui Liao, De-Wei Li, Cheng-You Du, Ming Li
BACKGROUND AND PURPOSE: Chronic inflammatory response is a risk factor for hepatocarcinogenesis and recurrence. This study aimed to develop a nomogram incorporating the combined albumin-bilirubin (ALBI) and fibrosis-4 (FIB-4) scores and the peritumoral inflammation score (PIS) to predict postoperative recurrence-free survival (RFS) of hepatocellular carcinoma (HCC). METHODS: The prognostic roles of preoperative ALBI and FIB-4 scores for HCC recurrence were investigated, and a nomogram was developed...
May 18, 2018: Journal of Gastrointestinal Surgery: Official Journal of the Society for Surgery of the Alimentary Tract
https://www.readbyqxmd.com/read/29777288/time-shifting-effects-of-methylphenidate-on-daily-rhythms-in-the-diurnal-rodent-arvicanthis-ansorgei
#5
Jorge Mendoza, Hester C van Diepen, Rob Rodrigues Pereira, Johanna H Meijer
People suffering of attention-deficit/hyperactivity disorder (ADHD) and treated with the psychostimulant methylphenidate (MPH) show sleep-wake cycle and daily rhythm alterations despite the beneficial effects of MPH on behavioral symptoms (i.e., hyperactivity, attention). In nocturnal rodents (i.e., mice), chronic exposure to MPH alters the neural activity of the circadian clock in the suprachiasmatic nucleus (SCN), behavioral rhythms, and the sleep-wake cycle. Here, we studied the effects of MPH on daily rhythms of behavior and body temperature of the diurnal rodent Arvicanthis ansorgei...
May 18, 2018: Psychopharmacology
https://www.readbyqxmd.com/read/29777126/discrete-taxa-of-saprotrophic-fungi-respire-different-ages-of-carbon-from-antarctic-soils
#6
Kevin K Newsham, Mark H Garnett, Clare H Robinson, Filipa Cox
Different organic compounds have distinct residence times in soil and are degraded by specific taxa of saprotrophic fungi. It hence follows that specific fungal taxa should respire carbon of different ages from these compounds to the atmosphere. Here, we test whether this is the case by radiocarbon (14 C) dating CO2 evolved from two gamma radiation-sterilised maritime Antarctic soils inoculated with pure single cultures of four fungi. We show that a member of the Helotiales, which accounted for 41-56% of all fungal sequences in the two soils, respired soil carbon that was aged up to 1,200 years BP and which was 350-400 years older than that respired by the other three taxa...
May 18, 2018: Scientific Reports
https://www.readbyqxmd.com/read/29777004/development-of-a-novel-spect-tracer-to-image-c-met-expression-in-non-small-cell-lung-cancer-in-a-human-tumor-xenograft
#7
Zhaoguo Han, Yadi Xiao, Kai Wang, Ji Yan, Zunyu Xiao, Fang Fang, Zhongnan Jin, Yang Liu, Xilin Sun, Baozhong Shen
Rationale: Elevated expression of the c-Met receptor plays a crucial role in cancers. In non-small cell lung cancer (NSCLC), aberrant activation of c-Met signaling pathway contributes to tumorigenesis and cancer progression, and may mediate acquired resistance to epidermal growth factor receptor-targeted therapy. c-Met is therefore emerging as a promising therapeutic target for treating NSCLC, and the methods for noninvasive in vivo assessment of c-Met expression will improve NSCLC treatment and diagnosis. Methods: A new peptide-based (cMBP) radiotracer targeting c-Met, 99m Tc-hydrazine nicotinamide (HYNIC)-cMBP, was developed for single photon emission computed tomography (SPECT) imaging...
May 18, 2018: Journal of Nuclear Medicine: Official Publication, Society of Nuclear Medicine
https://www.readbyqxmd.com/read/29776931/shuffling-the-neutral-drift-of-unspecific-peroxygenase-in-saccharomyces-cerevisiae
#8
Javier Martin-Diaz, Carmen Paret, Eva García-Ruiz, Patricia Molina-Espeja, Miguel Alcalde
Unspecific peroxygenase (UPO) is a highly promiscuous biocatalyst and its selective mono(per)oxygenase activity makes it useful for many synthetic chemistry applications. Among the broad repertory of library creation methods for directed enzyme evolution, genetic drift allows neutral mutations to be accumulated gradually within a polymorphic network of variants. In this study, we conducted a campaign of genetic drift with UPO in Saccharomyces cerevisiae so that neutral mutations were simply added and recombined in vivo With low mutational loading and an activity threshold of 45% of the parent's native function, mutant libraries enriched in folded and active UPO variants were generated...
May 18, 2018: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/29776561/circulating-micrornas-as-emerging-cardiac-biomarkers-responsive-to-acute-exercise
#9
David de Gonzalo-Calvo, Alberto Dávalos, Manuel Fernández-Sanjurjo, Laura Amado-Rodríguez, Susana Díaz-Coto, Cristina Tomás-Zapico, Ana Montero, Ángela García-González, Vicenta Llorente-Cortés, Maria Eugenia Heras, Araceli Boraita Pérez, Ángel E Díaz-Martínez, Natalia Úbeda, Eduardo Iglesias-Gutiérrez
BACKGROUND: Circulating microRNAs (c-miRNAs) are mediators of intercellular communication with great potential as cardiac biomarkers. The analysis of c-miRNAs in response to physiological stress, such as exercise, would provide valuable information for clinical practice and a deeper understanding of the molecular response to physical activity. Here, we analysed for the first time the acute exercise response of c-miRNAs reported as biomarkers of cardiac disease in a well-characterized cohort of healthy active adults...
August 1, 2018: International Journal of Cardiology
https://www.readbyqxmd.com/read/29775898/particle-induced-sirt1-downregulation-promotes-osteoclastogenesis-and-osteolysis-through-er-stress-regulation
#10
Liang Zhang, Dongmei Bao, Peng Li, Zhidong Lu, Long Pang, Zhirong Chen, Haohui Guo, Zhihui Gao, Qunhua Jin
BACKGROUND: Sirtuin 1 (SIRT1) downregulation has been found to be induced by wear particles in aseptic prosthesis loosening (APL). Osteoclastogenesis and osteoclast activation are the main pathological factors associated with APL. However, whether SIRT1 downregulation contributes to the formation and activation of osteoclasts through the induction of endoplasmic reticulum (ER) stress is unclear. METHODS: To address this, an osteolysis mouse model was used in which animals were treated with the SIRT1 activator, resveratrol (RES), or an ER stress inhibitor, 4-PBA, for two weeks...
May 15, 2018: Biomedicine & Pharmacotherapy, Biomédecine & Pharmacothérapie
https://www.readbyqxmd.com/read/29775880/photocatalytic-reductive-dechlorination-of-2-chlorodibenzo-p-dioxin-by-pd-modified-g-c-3-n-4-photocatalysts-under-uv-vis-irradiation-efficacy-kinetics-and-mechanism
#11
Jiafeng Ding, Gaoyuan Long, Yang Luo, Runze Sun, Mengxia Chen, Yajun Li, Yanfang Zhou, Xinhua Xu, Weirong Zhao
Polychlorinated dibenzo-p-dioxins (PCDDs), as a group of notorious anthropogenic environmental toxicants, are arguably ubiquitous in nature. In this study, we investigated the photocatalytic reductive dechlorination of 2-chlorodibenzo-p-dioxin (2-CDD) over Pd/g-C3 N4 catalysts under UV-vis irradiation. The g-C3 N4 and a series of Pd/g-C3 N4 catalysts were prepared by thermal polymerization and mechanical mixing-illumination method and characterized by XRD, TEM, BET, SEM and UV-vis DRS analyses. Among all the samples, the Pd/g-C3 N4 (5 wt%) yielded the optimal dechlorination activity with a total 2-CDD conversion of 54% within 4 h, and 76% of those converted 2-CDD were evolved to dibenzo-p-dioxin (DD)...
May 9, 2018: Journal of Hazardous Materials
https://www.readbyqxmd.com/read/29775718/biochemical-characterization-of-a-highly-thermostable-amylosucrase-from-truepera-radiovictrix-dsm-17093
#12
Xingtong Zhu, Yuqing Tian, Wei Xu, Yuxiang Bai, Tao Zhang, Wanmeng Mu
In this study, a novel recombinant amylosucrase from Truepera radiovictrix DSM 17093 was characterized and found to produce α-glucans from sucrose. The enzyme showed maximum total and transglucosylation activities at pH 7.5 and maximum hydrolysis activity at pH 5.5. The optimum temperature for total, transglucosylation, and hydrolysis activities were determined to be 45, 45, and 50 °C, respectively. When the conversion of 100 mM sucrose was catalyzed at 35, 45, and 55 °C for 24 h, TR-ASase produced α-(1,4) glucans with average DPs of 59, 45, and 37, respectively...
May 15, 2018: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/29775711/co-expression-purification-and-characterization-of-the-lipase-and-foldase-of-burkholderia-contaminans-lteb11
#13
Robson Carlos Alnoch, Adriano Alves Stefanello, Viviane de Paula Martini, Jeferson Luiz Richter, Cesar Mateo, Emanuel Maltempi de Souza, David Alexander Mitchell, Marcelo Muller-Santos, Nadia Krieger
Genes encoding lipase LipBC (lipA) and foldase LifBC (lipB) were identified in the genome of Burkholderia contaminans LTEB11. Analysis of the predicted amino acid sequence of lipA showed its high identity with lipases from Pseudomonas luteola (91%), Burkholderia cepacia (96%) and Burkholderia lata (97%), and classified LipBC lipase in the lipase subfamily I.2. The genes lipA and lipB were amplified and cloned into expression vectors pET28a(+) and pT7-7, respectively. His-tagged LipBC and native LifBC were co-expressed in Escherichia coli and purified...
May 15, 2018: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/29775704/alkaline-active-cyanide-dihydratase-of-flavobacterium-indicum-mtcc-6936-growth-optimization-purification-characterization-and-in-silico-analysis
#14
Virender Kumar, Vijay Kumar, Tek Chand Bhalla
The present work explores a rare cyanide dihydratase of Flavobacterium indicum MTCC 6936 for its potential of cyanide degradation. The enzyme is purified to 12 fold with a yield of 76%. SDS and native-PAGE analysis revealed that enzyme was monomer of 40 kDa size. The enzyme works well in mesophilic range at wide array of pH. The thermostability profile of cyanide dihydratase revealed that the enzyme is quite stable at 30 °C and 35 °C with half-life of 6 h 30 min and 5 h respectively. Km and Vmax for cyanide dihydratase of F...
May 15, 2018: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/29775416/downregulation-of-the-%C3%AE-1-and-%C3%AE-1-subunit-of-sgc-in-arterial-smooth-muscle-cells-of-opscc-is-hpv-independent
#15
Y Korkmaz, H C Roggendorf, O G Siefer, J Seehawer, T Imhof, M Plomann, W Bloch, A Friebe, C U Huebbers
The nitric oxide (NO)-sensitive soluble guanylyl cyclase (sGC) is a heterodimeric enzyme with an α and β subunit. NO binds to heme of the β1 -subunit of sGC, activates the enzyme in the reduced heme iron state in vascular smooth muscle cells (VSMCs), and generates cGMP-inducing vasodilatation and suppression of VSMC proliferation. In the complex tumor milieu with higher levels of reactive oxygen species (ROS), sGC heme iron may become oxidized and insensitive to NO. To change sGC from an NO-insensitive to NO-sensitive state or NO-independent manner, protein expression of sGC in VSMC is required...
May 1, 2018: Journal of Dental Research
https://www.readbyqxmd.com/read/29775390/polarization-and-distribution-of-tumor-associated-macrophages-and-cox-2-expression-in-basal-cell-carcinoma-of-the-ocular-adnexae
#16
Ute Kaiser, Karin U Loeffler, Jennifer Nadal, Frank G Holz, Martina C Herwig-Carl
PURPOSE: Basal cell carcinoma (BCC) is a locally invasive skin tumor which can be subdivided into a circumscribed nodular and an invasive fibrosing subtype. There is increasing evidence that macrophages play an important role in interacting between tumor cells and their microenvironment, thereby affecting not only the invasive potential but also the patients' prognosis. Thus, we wanted to compare these two BCC variants with regard to tumor-related inflammation, COX-2 expression, distribution and polarization of tumor-associated macrophages...
May 18, 2018: Current Eye Research
https://www.readbyqxmd.com/read/29775321/direct-ortho-c-h-aminoalkylation-of-2-substituted-pyridine-derivatives-catalyzed-by-yttrium-complexes-with-n-n-diarylethylenediamido-ligands
#17
Abhinanda Kundu, Mariko Inoue, Haruki Nagae, Hayato Tsurugi, Kazushi Mashima
A mixed ligated amidoyttrium complex, Y(NBn2 )(L1)(THF)2 (8, L1 = N,N'-bis(2,6-diisopropylphenyl)ethylenediamine), served as a catalyst for addition of the ortho-pyridyl C(sp2 )-H bond of 2-substituted pyridines to non-activated imines; complex 8 showed superior catalytic performance compared with Y[N(SiMe3 )2 ]3 (1) and Y[N(SiMe3 )2 ]2 (NBn2 )(THF) (2). Concerning the reaction mechanism, we conducted a stoichiometric reaction of an alkylyttrium complex, Y(CH2 SiMe3 )(L1)(THF)2 (7), with 2-ethylpyridine (4e), giving a mixture of (η3 -pyridylmethyl)yttrium complex 9 and (η2 -pyridyl)yttrium complex 10 along with elimination of SiMe4 ...
May 18, 2018: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/29775310/fragment-based-discovery-of-a-potent-orally-bioavailable-inhibitor-which-modulates-the-phosphorylation-and-catalytic-activity-of-erk1-2
#18
Tom D Heightman, Valerio Berdini, Hannah Braithwaite, Ildiko Maria Buck, Megan Cassidy, Juan Castro, Aurelie Courtin, James E H Day, Charlotte East, Lynsey Fazal, Brent Graham, Charlotte M Griffiths-Jones, John F Lyons, Vanessa Martins, Sandra Muench, Joanne M Munck, David Norton, Marc O'Reilly, Nick Palmer, Puja Pathuri, Michael Reader, David C Rees, Sharna J Rich, Caroline Richardson, Harpreet Saini, Neil T Thompson, Nicola G Wallis, Hugh Walton, Nicola E Wilsher, Alison J-A Woolford, Michael Cooke, David Cousin, Stuart Onions, Jonathan Shannon, John Watts, Christopher W Murray
Aberrant activation of the MAPK pathway drives cell proliferation in multiple cancers. Inhibitors of BRAF and MEK kinases are approved for the treatment of BRAF mutant melanoma, but resistance frequently emerges, often mediated by increased signalling through ERK1/2. Here we describe the fragment based generation of ERK1/2 inhibitors which block catalytic phosphorylation of downstream substrates such as RSK but also modulate phosphorylation of ERK1/2 by MEK without directly inhibiting MEK. X-ray crystallographic and biophysical fragment screening followed by structure-guided optimization and growth from the hinge into a pocket proximal to the C-α helix afforded highly potent ERK1/2 inhibitors with excellent kinome selectivity...
May 18, 2018: Journal of Medicinal Chemistry
https://www.readbyqxmd.com/read/29775067/rhodium-iii-catalyzed-redox-neutral-synthesis-of-isoquinolinium-salts-via-c-h-activation-of-imines
#19
Miaomiao Tian, Guangfan Zheng, Xuesen Fan, Xingwei Li
Redox-neutral synthesis of isoquinolinium salts via C-H activation of pre-synthesized or in situ formed imines and coupling with α-diazo ketoesters have been realized, where a zinc salt promotes cyclization as well as provides a counter anion. Under three-component conditions, both ketone and aldehydes are viable arene sources. The coupling of imines with diazo malonates under similar conditions afforded isoquinolin-3-ones as the coupling product.
May 18, 2018: Journal of Organic Chemistry
https://www.readbyqxmd.com/read/29775061/direct-photocatalytic-s-h-bond-cyanation-with-green-cn-source
#20
Wei Guo, Wen Tan, Mingming Zhao, Lvyin Zheng, Kailiang Tao, Deliang Chen, XiaoLin Fan
Herein we report a novel C-S bond cleavage and reconstruction strategy for the synthesis of thiocyanates through direct photocatalytic S-H bond cyanation from thiols and inorganic thiocyanate salts. In our strategy, the unprecedented example of cutting off C-S bond of SCN- to deliver the green "CN" sources is demonstrated. This transformation features nontoxic and inexpensive "CN" sources, available starting materials, metal-/base-/ligand-/peroxide-free, high step economy and mild conditions...
May 18, 2018: Journal of Organic Chemistry
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