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Suman Mallick, Kaushik Pal, Falguni Chandra, Apurba L Koner
Host-guest complexation of mono and dicationic quinine with cucurbit[7]uril (CB7), a water-soluble macrocyclic host molecule, has been investigated. Job's plot, time-resolved anisotropy as well as concentration dependent NMR titration confirm the binding of two CB7 macrocycles with one quinine molecule. The binding affinity of dicationic quinine with CB7 is one order of magnitude higher than the binding constant of mono-cationic quinine. Such preferential binding results in one unit pKa shift in the ground-state of the quinoline ring...
October 26, 2016: Physical Chemistry Chemical Physics: PCCP
Zhao-Guang Tan, Wei-Hong Gao, Xiang-Sheng Cai, Fang Wang, Hong-Xiang Hui
OBJECTIVE: To investigate the effect of glucagon-like peptide 1 (GLP-1) on cognitive dysfunction in diabetic rats. METHODS: Male SD rats were randomly divided into normal control group, diabetes mellitus (DM) group, and GLP-1 treatment group. Rat models of type 2 diabetes were established by high-sugar and high-fat feeding and streptozotocin (STZ) injection, and 25 days after the onset of diabetes, GLP-1 was infused in GLP-1 treatment group at the rate of 30 pmol·kg(-1)·min(-1) via a subcutaneous osmotic pump for 7 days...
October 20, 2016: Nan Fang Yi Ke da Xue Xue Bao, Journal of Southern Medical University
Daniel P Brink, Celina Borgström, Felipe G Tueros, Marie F Gorwa-Grauslund
BACKGROUND: The sugar sensing and carbon catabolite repression in Baker's yeast Saccharomyces cerevisiae is governed by three major signaling pathways that connect carbon source recognition with transcriptional regulation. Here we present a screening method based on a non-invasive in vivo reporter system for real-time, single-cell screening of the sugar signaling state in S. cerevisiae in response to changing carbon conditions, with a main focus on the response to glucose and xylose. RESULTS: The artificial reporter system was constructed by coupling a green fluorescent protein gene (yEGFP3) downstream of endogenous yeast promoters from the Snf3p/Rgt2p, SNF1/Mig1p and cAMP/PKA signaling pathways: HXT1p/2p/4p; SUC2p, CAT8p; TPS1p/2p and TEF4p respectively...
October 24, 2016: Microbial Cell Factories
Seung-Hee Lee, Jaehoon Shim, Ye-Hwang Cheong, Sun-Lim Choi, Yong-Woo Jun, Sue-Hyun Lee, Yeon-Su Chae, Jin-Hee Han, Yong-Seok Lee, Jin-A Lee, Chae-Seok Lim, Kausik Si, Stefan Kassabov, Igor Antonov, Eric R Kandel, Bong-Kiun Kaang, Deok-Jin Jang
Two pharmacologically distinct types of local protein synthesis are required for synapse- specific long-term synaptic facilitation (LTF) in Aplysia: one for initiation and the other for maintenance. ApCPEB, a rapamycin sensitive prion-like molecule regulates a form of local protein synthesis that is specifically required for the maintenance of the LTF. However, the molecular component of the local protein synthesis that is required for the initiation of LTF and that is sensitive to emetine is not known. Here, we identify a homolog of ApCPEB responsible for the initiation of LTF...
October 22, 2016: Molecular Brain
Xiang Ren, Qihang Guo, Jianhui Chen, Hujun Xie, Qing Xu, Zhan Lu
The visible-light-promoted diastereodivergent intramolecular oxyamination of alkenes and amination of unactivated C(Sp3)-H bonds is described to construct oxazolindinones, pyrrolidinones and imidazolidones via mild generation of primary amidyl radicals from functionalized hydroxylamines. A unique phenomenon on highly diastereoselective ring-opening of aziridines controlled by electron sacrifices was observed. High diastereoselective amino alcohols derivatives were obtained efficiently through this protocol in gram scales...
October 22, 2016: Chemistry: a European Journal
Pavel Kubáň, Knut Fredrik Seip, Astrid Gjelstad, Stig Pedersen-Bjergaard
This work investigated selective micro-electromembrane extractions (μ-EMEs) of the colored indicators metanil yellow and congo red (visual proof-of-principle) and the small drug substances nortriptyline, papaverine, mianserin, and citalopram (model analytes) based on their acid-base strength. With two free liquid membranes (FLMs), the target analytes were extracted from aqueous donor solution, across FLM 1 (1-pentanol, 1-ethyl-2-nitrobenzene (ENB) or 4-nitrocumene (4-NC)), into aqueous acceptor solution 1, further across FLM 2 (1-pentanol, ENB or 4-NC), and finally into aqueous acceptor solution 2...
November 2, 2016: Analytica Chimica Acta
Lukasz P Kozlowski
BACKGROUND: Accurate estimation of the isoelectric point (pI) based on the amino acid sequence is useful for many analytical biochemistry and proteomics techniques such as 2-D polyacrylamide gel electrophoresis, or capillary isoelectric focusing used in combination with high-throughput mass spectrometry. Additionally, pI estimation can be helpful during protein crystallization trials. RESULTS: Here, I present the Isoelectric Point Calculator (IPC), a web service and a standalone program for the accurate estimation of protein and peptide pI using different sets of dissociation constant (pKa) values, including two new computationally optimized pKa sets...
October 21, 2016: Biology Direct
Laura de Diego-García, Mercedes Ramírez-Escudero, Álvaro Sebastián-Serrano, Juan Ignacio Diaz-Hernández, Jesús Pintor Just, José J Lucas, Miguel Díaz-Hernández
The Ubiquitin-Proteasome System (UPS) is essential for the regulation of the cellular proteostasis. Indeed, it has been postulated that an UPS dysregulation is the common mechanism that underlies several neurological disorders. Considering that extracellular nucleotides, through their selective P2Y2 receptor (P2Y2R), play a neuroprotective role in various neurological disorders that course with an UPS impairment, we wonder if this neuroprotective capacity resulted from their ability to modulate the UPS. Using a cellular model expressing two different UPS reporters, we found that the stimulation of P2Y2R by its selective agonist Up4U induced a significant reduction of UPS reporter levels...
October 18, 2016: Biochimica et Biophysica Acta
Elena Sugrue, Paul D Carr, Colin Scott, Colin J Jackson
The desolvation of ionizable residues in the active sites of enzymes and the subsequent effects on catalysis and thermostability have been studied in model systems, yet little is known regarding how enzymes can naturally evolve active sites with highly reactive and desolvated charges. Variants of triazine hydrolase (TrzN) with significant differences in their active sites have been isolated from different bacterial strains: TrzN from Nocardioides sp. strain MTD22 contains a catalytic glutamate residue (Glu241) that is surrounded by hydrophobic and aromatic second-shell residues (Pro214, Tyr215), whereas TrzN from Nocardioides sp...
October 21, 2016: Biochemistry
Purva P Bhojane, Michael R Duff, Khushboo Bafna, Gabriella P Rimmer, Pratul K Agarwal, Elizabeth E Howell
Folate, or vitamin B9, is an important compound in one carbon metabolism. Previous studies have found weaker binding of dihydrofolate to dihydrofolate reductase in the presence of osmolytes. In other words, osmolytes are more difficult to remove from the dihydrofolate solvation shell than water; this shifts the equilibrium towards the free ligand and protein species. This study uses vapor pressure osmometry to explore the interaction of folate with the model osmolyte, glycine betaine. This method yields a preferential interaction potential (μ23/RT value)...
October 21, 2016: Biochemistry
Nicole Mons, Daniel Beracochea
A prime mechanism that contributes to the development and maintenance of alcoholism is the dysregulation of the hypothalamic-pituitary-adrenal axis activity and the release of glucocorticoids (cortisol in humans and primates, corticosterone in rodents) from the adrenal glands. In the brain, sustained, local elevation of glucocorticoid concentration even long after cessation of chronic alcohol consumption compromises functional integrity of a circuit, including the prefrontal cortex (PFC), the hippocampus (HPC), and the amygdala (AMG)...
2016: Frontiers in Psychiatry
Beate Schwer, Fahad Khalid, Stewart Shuman
Saccharomyces cerevisiae Dbr1 is a manganese-dependent RNA debranching enzyme that cleaves the 2'-5' phosphodiester bond of the lariat introns formed during pre-mRNA splicing. Dbr1 is a member of the binuclear metallophosphoesterase enzyme superfamily. We showed previously via alanine scanning that RNA debranching in vivo and in vitro depends on conserved active site residues His13, Asp40, Asn85, His86, His179, His231, and His233. Here, by extending the alanine scan, we added Cys11 to the ensemble of essential active site components...
October 7, 2016: RNA
Rebecca J Hron, Branko S Jursic, Donna M Neumann
Six structural motifs based on the initial (lead) structure of merbarone were designed, prepared, and tested against the glioblastoma LN-229 cell line. Three different structural moieties were modified in the search for optimal glioblastoma activity: the 1,3-diazinane moiety, the aryl moiety, and the heteroatom linker. Calculated molecular descriptors such as lipophilicity (ClogP), acidic strength (calculated pKa), and polar surface area (PSA) were used to design a diverse structural library of these compounds...
October 4, 2016: Bioorganic & Medicinal Chemistry
Angelo Antonio D'Archivio, Maria Anna Maggi
Response surface methodology, coupled to a full factorial three-level experimental design, was applied to investigate the combined influence of pH (between 7.0 and 8.6) and composition of methanol-water mixtures (between 30 and 70% v/v of methanol content) on the stability of curcumin and its analogues demethoxycurcumin and bisdemethoxycurcumin. The response plots revealed that addition of methanol noticeably improved the stability of curcuminoids, this effect being both pH- and structure-dependent. In the central point of the experimental domain, half-life times of curcumin, demethoxycurcumin and bisdemethoxycurcumin were 3...
March 15, 2017: Food Chemistry
Xiuqing Tian, Rui Guo, Yujiao Zhang, Lingling Xu, Xianbing Liu, Yinglong Hou
OBJECTIVE: To observe the effects of sympathetic overactivity on the immune system involved in the imbalance of T helper (Th) lymphocytes, we investigated the correlation between autonomic dysregulation and the generation of regulatory T (Treg) and Th1 chemokines in patients with acute coronary syndrome (ACS). METHODS: Blood samples obtained from patients with coronary artery disease and controls were analyzed for levels of Th1 and Treg cells and their associated cytokines by flow cytometry...
October 21, 2016: Neuroimmunomodulation
Erik Richter, Manuela Harms, Katharina Ventz, Rolf Nölker, Martin J Fraunholz, Jörg Mostertz, Falko Hochgräfe
Internalization of Staphylococcus aureus by non-professional phagocytic cells is a major suspected cause of persistent and difficult-to-treat infections, including pneumonia. In this study, we established an infection model with 16HBE14o- human bronchial epithelial cells and demonstrated internalization, escape from phagosomal clearance and intracellular replication of S. aureus HG001 within the first four hours post-infection. We used quantitative phosphoproteomics to identify characteristic signaling networks in the host at different infection stages...
October 20, 2016: Journal of Proteome Research
Hao Xu, Manxi Zhao, Shenghui Liang, Quanshu Huang, Yunchuan Xiao, Liang Ye, Qinyi Wang, Longmei He, Lanxiang Ma, Hua Zhang, Li Zhang, Hui Jiang, Xiao Ke, Yuchun Gu
Puerarin, a known isoflavone, is commonly found as a Chinese herb medicine. It is widely used in China to treat cardiac diseases such as angina, cardiac infarction and arrhythmia. However, its cardioprotective mechanism remains unclear. In this study, puerarin significantly prolonged ventricular action potential duration (APD) with a dosage dependent manner in the micromolar range on isolated rat ventricular myocytes. However, submicromolar puerarin had no effect on resting membrane potential (RMP), action potential amplitude (APA) and maximal velocity of depolarization (Vmax) of action potential...
October 20, 2016: Scientific Reports
Hao Huang, Linfu Li, Weimei Shi, Hai Liu, Jianqiong Yang, Xiaoliang Yuan, Longhuo Wu
Nobiletin (NOB) chemically known as 5,6,7,8,3',4'-hexamethoxyflavone is a dietary polymethoxylated flavonoid found in Citrus fruits. Recent evidences show that NOB is a multifunctional pharmaceutical agent. The various pharmacological activities of NOB include neuroprotection, cardiovascular protection, antimetabolic disorder, anticancer, anti-inflammation, and antioxidation. These events may be underpinned by modulation of signaling cascades, including PKA/ERK/MEK/CREB, NF-κB, MAPK, Ca(2+)/CaMKII, PI3K/Akt1/2, HIF-1α, and TGFβ signaling pathways...
2016: Evidence-based Complementary and Alternative Medicine: ECAM
Feng-Li Wu, Guang Zhang, Ang Ren, Zhi-Hao Dang, Liang Shi, Ai-Liang Jiang, Ming-Wen Zhao
Ganoderma lucidum is a medicinal macrofungus that is widely used in traditional Chinese medicine. Nonetheless, the scarcity of basic biological studies of this organism has hindered the further development of its commercial value. The pH-responsive transcription factor PacC/Rim101 governs the adaptation to environmental pH, the development and the secondary metabolism of many fungi. In this study, a homologue of PacC/Rim101 that encodes GlPacC was identified in the higher basidiomycete G. lucidum GlPacC is composed of 807 amino acids and contains three typical C2H2 zinc-finger domains, two potential PEST domains, a putative PKA phosphorylation site, and a putative nuclear localization signal (NLS)...
October 19, 2016: Mycologia
Alice Strohmeier, Gesche Först, Philipp Tauber, Rolf Schubert
The interaction of liposomal membranes composed of soybean phosphatidylcholine with the bile salts (BSs) cholate (Ch), glycocholate (GC), chenodeoxycholate (CDC), and glycochenodeoxycholate (GCDC) was studied. The BSs differed with regard to their lipophilicity, pKa values, and the size of their hydrophilic moiety. Their membrane interactions were investigated using Laurdan as a membrane-anchored fluorescent dye. The apparent membrane/water partition coefficient, D, at pH 7.4 was calculated from binding plots and compared with direct binding measurements using ultracentrifugation as a reference...
October 18, 2016: Biophysical Journal
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