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https://www.readbyqxmd.com/read/28549266/self-cascade-reaction-catalyzed-by-cuo-nanoparticle-based-dual-functional-enzyme-mimics
#1
Ai-Ling Hu, Hao-Hua Deng, Xiao-Qing Zheng, Yan-Yu Wu, Xiu-Ling Lin, Ai-Lin Liu, Xing-Hua Xia, Hua-Ping Peng, Wei Chen, Guo-Lin Hong
It is desirable but challenging to assemble various biomimetic properties into a functional catalytic cascade system. In this work, cupric oxide nanoparticles were investigated as oxidase mimics for the aerobic oxidation of cysteine to cystine with the generation of hydrogen peroxide. Coupling this property with the peroxidase-like activity of CuO nanoparticles, we constructed a self-organized cascade reaction system based on a single-component nanozyme, which includes the oxidation of cysteine to yield cystine and hydrogen peroxide and the hydrogen peroxide-mediated oxidation of terephthalic acid to produce a fluorescence change...
May 19, 2017: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/28544675/cyclotides-overview-and-biotechnological-applications
#2
REVIEW
Andrew Gould, Julio A Camarero
Cyclotides are globular microproteins with a unique head-to-tail cyclized backbone, stabilized by three disulfide bonds forming a cystine knot. This unique circular backbone topology and knotted arrangement of three disulfide bonds makes them exceptionally stable to chemical, thermal, and biological degradation compared to other peptides of similar size. In addition, cyclotides have been shown to be highly tolerant to sequence variability, aside from the conserved residues forming the cystine knot. Cyclotides can also cross cellular membranes and are able to modulate intracellular protein-protein interactions, both in vitro and in vivo...
May 24, 2017: Chembiochem: a European Journal of Chemical Biology
https://www.readbyqxmd.com/read/28544383/self-assembled-biomimetic-chloroplast-coupled-photoenzymatic-reaction-for-sustainable-synthesis-of-fuel
#3
Xuehai Yan, Kai Liu, Chengqian Yuan, Qianli Zou, Zengchun Xie
Prototypes of biosystems provide good blueprints for the design and creation of biomimetic systems. However, mimicking both the sophisticated natural structures and their complex biological functions still remains a great challenge. Herein, biomimetic chloroplasts have been fabricated by one-step bio-inspired amino acid mineralization and simultaneous integration of catalytically active units. Hierarchically structured crystals are obtained by metal ion-directed self-assembly of cystine (the oxidized dimer form of the amino acid cysteine), with porous structure and stacking nanorods, which show similar architectural principles to chloroplasts...
May 22, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28542706/modulatory-features-of-the-novel-spider-toxin-%C3%AE-trtx-df1a-isolated-from-the-venom-of-the-spider-davus-fasciatus
#4
Fernanda C Cardoso, Zoltan Dekan, Jennifer J Smith, Jennifer R Deuis, Irina Vetter, Volker Herzig, Paul F Alewood, Glenn F King, Richard J Lewis
BACKGROUND AND PURPOSE: Naturally occurring dysfunction in NaV channels results in complex disorders such as chronic pain, making these channels an attractive target for new therapies. In the pursuit of novel NaV modulators, we investigated spider venoms for new inhibitors of NaV channels. EXPERIMENTAL APPROACH: We used high-throughput screens to identify a NaV modulator in venom of the spider Davus fasciatus. Further characterization of this venom peptide was undertaken using fluorescent and electrophysiological assays, molecular modeling and a rodent pain model...
May 24, 2017: British Journal of Pharmacology
https://www.readbyqxmd.com/read/28533366/mechanism-of-h2s-mediated-protection-against-oxidative-stress-in-escherichia-coli
#5
Alexander Mironov, Tatyana Seregina, Maxim Nagornykh, Lyly G Luhachack, Natalya Korolkova, Liubov Errais Lopes, Vera Kotova, Gennady Zavilgelsky, Rustem Shakulov, Konstantin Shatalin, Evgeny Nudler
Endogenous hydrogen sulfide (H2S) renders bacteria highly resistant to oxidative stress, but its mechanism remains poorly understood. Here, we report that 3-mercaptopyruvate sulfurtransferase (3MST) is the major source of endogenous H2S in Escherichia coli Cellular resistance to H2O2 strongly depends on the activity of mstA, a gene that encodes 3MST. Deletion of the ferric uptake regulator (Fur) renders ∆mstA cells hypersensitive to H2O2 Conversely, induction of chromosomal mstA from a strong pLtetO-1 promoter (P tet -mstA) renders ∆fur cells fully resistant to H2O2 Furthermore, the endogenous level of H2S is reduced in ∆fur or ∆sodA ∆sodB cells but restored after the addition of an iron chelator dipyridyl...
May 22, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28490132/heat-induced-inactivation-mechanism-of-soybean-bowman-birk-inhibitors
#6
Hui He, Xingfei Li, Xiangzhen Kong, Yufei Hua, Yeming Chen
Due to the complications of the soymilk system, the heat-induced Bowman-Birk inhibitor (BBI) inactivation mechanism is not well known. In this study, two BBI samples with low and high purities were prepared from soymilk. It was confirmed that three groups (A, C, and D) of BBI, which are contained in soybean seeds, were transferred into soymilk during processing. On heating, it was found that 1) the two subdomains of BBI were not equally heat stable, 2) the conformation of BBI gradually changed, 3) some amino acid residues (namely, cystine, serine and lysine) in BBI were degraded, 4) BBI did not tend to form intermolecular cross-links with another BBI, but did slightly with non-BBI proteins...
October 1, 2017: Food Chemistry
https://www.readbyqxmd.com/read/28471681/understanding-the-diversity-and-distribution-of-cyclotides-from-plants-of-varied-genetic-origin
#7
Anjaneya S Ravipati, Aaron G Poth, Sónia Troeira Henriques, Murari Bhandari, Yen-Hua Huang, Jaime Nino, Michelle L Colgrave, David J Craik
Cyclotides are a large family of naturally occurring plant-derived macrocyclic cystine-knot peptides, with more than 400 having been identified in species from the Violaceae, Rubiaceae, Cucurbitaceae, Fabaceae, and Solanaceae families. Nevertheless, their specialized distribution within the plant kingdom remains poorly understood. In this study, the diversity of cyclotides was explored through the screening of 197 plants belonging to 43 different families. In total, 28 cyclotides were sequenced from 15 plant species, one of which belonged to the Rubiaceae and 14 to the Violaceae...
May 4, 2017: Journal of Natural Products
https://www.readbyqxmd.com/read/28470569/transport-of-bmaa-into-neurons-and-astrocytes-by-system-xc
#8
Rebecca Albano, Doug Lobner
The study of the mechanism of β-N-methylamino-L-alanine (BMAA) neurotoxicity originally focused on its effects at the N-methyl-D-aspartate (NMDA) receptor. In recent years, it has become clear that its mechanism of action is more complicated. First, there are certain cell types, such as motor neurons and cholinergic neurons, where the dominate mechanism of toxicity is through action at AMPA receptors. Second, even in cortical neurons where the primary mechanism of toxicity appears to be activation of NMDA receptors, there are other mechanisms involved...
May 3, 2017: Neurotoxicity Research
https://www.readbyqxmd.com/read/28469845/effect-of-bacillus-subtilis-and-bacillus-licheniformis-supplementation-in-diets-with-low-and-high-protein-content-on-ileal-crude-protein-and-amino-acid-digestibility-and-intestinal-microbiota-composition-of-growing-pigs
#9
Chanwit Kaewtapee, Katharina Burbach, Georgina Tomforde, Thomas Hartinger, Amélia Camarinha-Silva, Sonja Heinritz, Jana Seifert, Markus Wiltafsky, Rainer Mosenthin, Pia Rosenfelder-Kuon
BACKGROUND: Bacillus spp. seem to be an alternative to antimicrobial growth promoters for improving animals' health and performance. However, there is little information on the effect of Bacillus spp. in combination with different dietary crude protein (CP) levels on the ileal digestibility and microbiota composition. Therefore, the objective of this study was to determine the effect of Bacillus spp. supplementation to low- (LP) and high-protein diets (HP) on ileal CP and amino acid (AA) digestibility and intestinal microbiota composition...
2017: Journal of Animal Science and Biotechnology
https://www.readbyqxmd.com/read/28468283/heparin-heparan-sulphate-and-the-tgf-%C3%AE-cytokine-superfamily
#10
REVIEW
Chris C Rider, Barbara Mulloy
Of the circa 40 cytokines of the TGF-β superfamily, around a third are currently known to bind to heparin and heparan sulphate. This includes TGF-β1, TGF-β2, certain bone morphogenetic proteins (BMPs) and growth and differentiation factors (GDFs), as well as GDNF and two of its close homologues. Experimental studies of their heparin/HS binding sites reveal a diversity of locations around the shared cystine-knot protein fold. The activities of the TGF-β cytokines in controlling proliferation, differentiation and survival in a range of cell types are in part regulated by a number of specific, secreted BMP antagonist proteins...
April 29, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/28466360/phase-1-study-of-sulfasalazine-and-cisplatin-for-patients-with-cd44v-positive-gastric-cancer-refractory-to-cisplatin-epoc1407
#11
Kohei Shitara, Toshihiko Doi, Osamu Nagano, Miki Fukutani, Hiromi Hasegawa, Shogo Nomura, Akihiro Sato, Takeshi Kuwata, Kai Asai, Yasuaki Einaga, Kenji Tsuchihashi, Kentaro Suina, Yusuke Maeda, Hideyuki Saya, Atsushi Ohtsu
A previous dose-escalation study of sulfasalazine (SSZ), an inhibitor of cystine-glutamate exchange transporter xc (-), in the variant form of CD44 (CD44v)-positive cancer stem cells (CSCs) suggested that administration of SSZ induces the reduction of CD44v-positive cells and intracellular reduced glutathione (GSH) levels in patients with advanced gastric cancer (AGC). Here we report a study to evaluate SSZ in combination with cisplatin in patients with CD44v-expressing AGC refractory to cisplatin. SSZ was given by oral administration four times daily with 2 weeks on and 1 week off...
May 2, 2017: Gastric Cancer
https://www.readbyqxmd.com/read/28466111/use-of-brevibacillus-choshinensis-for-the-production-of-biologically-active-brain-derived-neurotrophic-factor-bdnf
#12
Phillip A Angart, Rebecca J Carlson, Sarah Thorwall, S Patrick Walton
Brain-derived neurotrophic factor (BDNF) is a member of the neurotrophin family critical for neuronal cell survival and differentiation, with therapeutic potential for the treatment of neurological disorders and spinal cord injuries. The production of recombinant, bioactive BDNF is not practical in most traditional microbial expression systems because of the inability of the host to correctly form the characteristic cystine-knot fold of BDNF. Here, we investigated Brevibacillus choshinensis as a suitable expression host for bioactive BDNF expression, evaluating the effects of medium type (2SY and TM), temperature (25 and 30 °C), and culture time (48-120 h)...
May 2, 2017: Applied Microbiology and Biotechnology
https://www.readbyqxmd.com/read/28465352/cystinosin-the-small-gtpase-rab11-and-the-rab7-effector-rilp-regulate-intracellular-trafficking-of-the-chaperone-mediated-autophagy-receptor-lamp2a
#13
Jinzhong Zhang, Jennifer L Johnson, Jing He, Gennaro Napolitano, Mahalakshmi Ramadass, Celine Rocca, William B Kiosses, Cecilia Bucci, Qisheng Xin, Evripidis Gavathiotis, Ana María Cuervo, Stephanie Cherqui, Sergio D Catz
The lysosomal storage disease cystinosis, caused by cystinosin-deficiency, is characterized by cell malfunction, tissue failure and progressive renal injury despite cystine-depletion therapies. Cystinosis is associated with defects in chaperone-mediated autophagy (CMA), but the molecular mechanisms are incompletely understood. Here, we show CMA substrate accumulation in cystinotic kidney proximal tubule cells. We also found mislocalization of the CMA lysosomal receptor LAMP2A, and impaired substrate translocation into the lysosome caused by defective CMA in cystinosis...
May 2, 2017: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/28465261/challenges-in-the-evaluation-of-thiol-reactive-inhibitors-of-human-protein-disulfide-isomerase
#14
Celia K Foster, Colin Thorpe
This paper addresses how to evaluate the efficacy of the growing inventory of thiol-reactive inhibitors of mammalian protein disulfide Isomerase (PDI) enzymes under realistic concentrations of potentially competing thiol-containing peptides and proteins. For this purpose, we introduce a variant of the widely-used reductase assay by using a commercially-available cysteine derivative (BODIPY FL L-Cystine; BD-SS) that yields a 55-fold increase in fluorescence (excitation/emission; 490/513nm) on scission of the disulfide bond...
April 30, 2017: Free Radical Biology & Medicine
https://www.readbyqxmd.com/read/28458574/identification-of-capsazepine-as-a-novel-inhibitor-of-system-xc-and-cancer-induced-bone-pain
#15
Jennifer Fazzari, Matthew D Balenko, Natalie Zacal, Gurmit Singh
The cystine/glutamate antiporter has been implicated in a variety of cancers as a major mediator of redox homeostasis. The excess glutamate secreted by this transporter in aggressive cancer cells has been associated with cancer-induced bone pain (CIBP) from distal breast cancer metastases. High-throughput screening of small molecule inhibitors of glutamate release from breast cancer cells identified several potential compounds. One such compound, capsazepine (CPZ), was confirmed to inhibit the functional unit of system xc(-) (xCT) through its ability to block uptake of its radiolabeled substrate, cystine...
2017: Journal of Pain Research
https://www.readbyqxmd.com/read/28458443/renal-stone-characterization-using-high-resolution-imaging-mode-on-a-photon-counting-detector-ct-system
#16
A Ferrero, R Gutjahr, A Henning, S Kappler, A Halaweish, D Abdurakhimova, Z Peterson, J Montoya, S Leng, C McCollough
In addition to the standard-resolution (SR) acquisition mode, a high-resolution (HR) mode is available on a research photon-counting-detector (PCD) whole-body CT system. In the HR mode each detector consists of a 2x2 array of 0.225 mm × 0.225 mm subpixel elements. This is in contrast to the SR mode that consists of a 4x4 array of the same sub-elements, and results in 0.25 mm isotropic resolution at iso-center for the HR mode. In this study, we quantified ex vivo the capabilities of the HR mode to characterize renal stones in terms of morphology and mineral composition...
March 9, 2017: Proceedings of SPIE
https://www.readbyqxmd.com/read/28457879/the-role-of-system-xc-in-methamphetamine-induced-dopaminergic-neurotoxicity-in-mice
#17
Duy-Khanh Dang, Eun-Joo Shin, Hai-Quyen Tran, Dae-Joong Kim, Ji Hoon Jeong, Choon-Gon Jang, Seung-Yeol Nah, Hideyo Sato, Toshitaka Nabeshima, Yukio Yoneda, Hyoung-Chun Kim
The cystine/glutamate antiporter (system Xc(-), Sxc) transports cystine into cell in exchange for glutamate. Since xCT is a specific subunit of Sxc, we employed xCT knockout mice and investigated whether this antiporter affected methamphetamine (MA)-induced dopaminergic neurotoxicity. MA treatment significantly increased striatal oxidative burdens in wild type mice. xCT inhibitor [i.e., S-4-carboxy-phenylglycine (CPG), sulfasalazine] or an xCT knockout significantly protected against these oxidative burdens...
April 27, 2017: Neurochemistry International
https://www.readbyqxmd.com/read/28454016/bohr-effect-of-native-and-chemically-modified-hemoglobins-quantitative-analyses-based-on-the-wyman-equation
#18
Kehinde Onwochei Okonjo
Thirteen histidines and the α-chain terminal amino group (ACTA) make all of the contributions to the Bohr effect of human hemoglobin. The pKas of the 13 histidines in carbonmonoxy- and deoxyhemoglobin are known from (1)H NMR studies. Those of ACTA are not so precisely known. We employed the Wyman equation and the 13 histidine pairs of pKas to determine the pKas of ACTA by curve-fitting to hemoglobin Bohr effect data. Using all 14 pairs of pKas as preliminary data, we employed the Wyman equation to fit the Bohr data for hemoglobin chemically modified at Cys93β with cystamine, cystine and iodoacetamide...
April 18, 2017: Biophysical Chemistry
https://www.readbyqxmd.com/read/28442364/effects-of-repeated-cocaine-exposure-and-withdrawal-on-voluntary-ethanol-drinking-and-the-expression-of-glial-glutamate-transporters-in-mesocorticolimbic-system-of-p-rats
#19
Alaa M Hammad, Yusuf S Althobaiti, Sujan C Das, Youssef Sari
Glutamatergic neurotransmission within the brain's reward circuits plays a major role in the reinforcing properties of both ethanol and cocaine. Glutamate homeostasis is regulated by several glutamate transporters, including glutamate transporter type 1 (GLT-1), cystine/glutamate transporter (xCT), and glutamate aspartate transporter (GLAST). Cocaine exposure has been shown to induce a dysregulation in glutamate homeostasis and a decrease in the expression of GLT-1 and xCT in the nucleus accumbens (NAc). In this study, alcohol preferring (P) rats were exposed to free-choice of ethanol (15% and 30%) and/or water for five weeks...
April 22, 2017: Molecular and Cellular Neurosciences
https://www.readbyqxmd.com/read/28435838/thiol-trapping-and-metabolic-redistribution-of-sulfur-metabolites-enable-cells-to-overcome-cysteine-overload
#20
Anup Arunrao Deshpande, Muskan Bhatia, Sunil Laxman, Anand Kumar Bachhawat
Cysteine is an essential requirement in living organisms. However, due to its reactive thiol side chain, elevated levels of intracellular cysteine can be toxic and therefore need to be rapidly eliminated from the cellular milieu. In mammals and many other organisms, excess cysteine is believed to be primarily eliminated by the cysteine dioxygenase dependent oxidative degradation of cysteine, followed by the removal of the oxidative products. However, other mechanisms of tackling excess cysteine are also likely to exist, but have not thus far been explored...
March 27, 2017: Microbial Cell
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