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Ekaterina M Savelieva, Vladimir E Oslovsky, Dmitry S Karlov, Nikolay N Kurochkin, Irina A Getman, Sergey N Lomin, Georgy V Sidorov, Sergey N Mikhailov, Dmitry I Osolodkin, Georgy A Romanov
Biological effects of hormones in both plants and animals are based on high-affinity interaction with cognate receptors resulting in their activation. The signal of cytokinins, classical plant hormones, is perceived in Arabidopsis by three homologous membrane receptors: AHK2, AHK3, and CRE1/AHK4. To study the cytokinin-receptor interaction, we used 25 derivatives of potent cytokinin N6 -benzyladenine (BA) with substituents in the purine heterocycle and/or in the side chain. The study was focused primarily on individual cytokinin receptors from Arabidopsis...
March 12, 2018: Phytochemistry
Karamat Mohammad, Paméla Dakik, Younes Medkour, Mélissa McAuley, Darya Mitrofanova, Vladimir I Titorenko
The concentrations of some key metabolic intermediates play essential roles in regulating the longevity of the chronologically aging yeast Saccharomyces cerevisiae . These key metabolites are detected by certain ligand-specific protein sensors that respond to concentration changes of the key metabolites by altering the efficiencies of longevity-defining cellular processes. The concentrations of the key metabolites that affect yeast chronological aging are controlled spatially and temporally. Here, we analyze mechanisms through which the spatiotemporal dynamics of changes in the concentrations of the key metabolites influence yeast chronological lifespan...
March 15, 2018: International Journal of Molecular Sciences
Mohammad Bagher Ghavami, Habibeh Mirzadeh, Jamshid Mohammadi, Asghar Fazaeli
The human flea is an important ectoparasite causing serious public health problems worldwide. Planning and monitoring the control programs against this vector require the knowledge of population structure and vector competence. This study was carried out to identify molecular structure of internal transcribed spacer 1 (ITS1) of ribosomal gene and its capability in the survey of Pulex irritans populations as well as to investigate Rickettsia infection in these populations. Flea samples were collected via human baits from animal farms in two districts of Zanjan Province, northwest of Iran...
March 14, 2018: Parasitology Research
Uma Mahesh R Avula, Jonathan J Hernandez, Masatoshi Yamazaki, Carmen R Valdivia, Antony Chu, Alvaro Rojas-Pena, Kuljeet Kaur, Roberto Ramos-Mondragón, Justus M Anumonwo, Stanley Nattel, Héctor H Valdivia, Jérôme Kalifa
BACKGROUND: The mechanisms underlying spontaneous atrial fibrillation (AF) associated with atrial ischemia/infarction are incompletely elucidated. Here, we investigate the mechanisms underlying spontaneous AF in an ovine model of left atrial myocardial infarction (LAMI). METHODS AND RESULTS: LAMI was created by ligating the atrial branch of the left anterior descending coronary artery. ECG loop recorders were implanted to monitor AF episodes. In 7 sheep, dantrolene-a ryanodine receptor blocker-was administered in vivo during the 8-day observation period (LAMI-D, 2...
March 2018: Circulation. Arrhythmia and Electrophysiology
Silvia Ravera, Maria Grazia Signorello, Martina Bartolucci, Sara Ferrando, Lucia Manni, Federico Caicci, Daniela Calzia, Isabella Panfoli, Alessandro Morelli, Giuliana Leoncini
BACKGROUND INFORMATION: Energy demand in human platelets is very high, to carry out their functions. As for most human cells, the aerobic metabolism represents the primary energy source in platelets, even though mitochondria are negligibly represented. Following the hypothesis that other structures could be involved in chemical energy production, in this work, we have investigated the functional expression of an extramitochondrial aerobic metabolism in platelets. RESULTS: Oximetric and luminometric analyses showed that platelets consume large amounts of oxygen and produce ATP in the presence of common respiring substrates, such as pyruvate + malate or succinate, although morphological electron microscopy analysis showed that these contain few mitochondria...
March 14, 2018: Biology of the Cell
Zhiyi Liu, Dimitra Pouli, Carlo A Alonzo, Antonio Varone, Sevasti Karaliota, Kyle P Quinn, Karl Münger, Katia P Karalis, Irene Georgakoudi
Monitoring subcellular functional and structural changes associated with metabolism is essential for understanding healthy tissue development and the progression of numerous diseases, including cancer, diabetes, and cardiovascular and neurodegenerative disorders. Unfortunately, established methods for this purpose either are destructive or require the use of exogenous agents. Recent work has highlighted the potential of endogenous two-photon excited fluorescence (TPEF) as a method to monitor subtle metabolic changes; however, mechanistic understanding of the connections between the detected optical signal and the underlying metabolic pathways has been lacking...
March 2018: Science Advances
Jue Hou, Joshua Williams, Elliot Botvinick, Eric Potma, Bruce J Tromberg
Label-free non-linear optical microscopy (NLOM) based on two-photon excited fluorescence (TPEF) from cofactors Nicotinamide Adenine Dinucleotide (NADH) and Flavin Adenine Dinucleotide (FAD+) is widely used for high-resolution cellular redox imaging. In this work, we combined three, label-free NLOM imaging methods to quantitatively characterize breast cancer cells and their relative invasive potential: 1) TPEF optical redox ratio (ORR = FAD+/NADH + FAD+), 2) coherent Raman scattering (CRS) of cellular lipids, and 3) second harmonic generation (SHG) of extracellular matrix (ECM) collagen...
March 13, 2018: Cancer Research
Wanying Li, Dan Yu, Jingjuan Yu, Dengyun Zhu, Qian Zhao
ZmbZIP25 ( Zea mays bZIP (basic leucine zipper) transcription factor 25) is a function-unknown protein that belongs to the D group of the bZIP transcription factor family. RNA-seq data showed that the expression of ZmbZIP25 was tissue-specific in maize silks, and this specificity was confirmed by RT-PCR (reverse transcription-polymerase chain reaction). In situ RNA hybridization showed that ZmbZIP25 was expressed exclusively in the xylem of maize silks. A 5' RACE (rapid amplification of cDNA ends) assay identified an adenine residue as the transcription start site of the ZmbZIP25 gene...
March 12, 2018: International Journal of Molecular Sciences
Tatsuru Yamada, Shoji Fujiwara, Kyohhei Fujita, Yuji Tsuchido, Takeshi Hashimoto, Takashi Hayashita
The construction of supramolecular recognition systems based on specific host-guest interactions has been studied in order to design selective chemical sensors. In this study, guest-responsive receptors for ATP have been designed with cyclodextrins (CyDs) as a basic prototype of the turn-on type fluorescent indicator. We synthesized dipicolylamine (DPA)-modified CyD-Cu2+ complexes ( Cu·1 α , Cu·1 β , and Cu·1 γ ), and evaluated their recognition capabilities toward phosphoric acid derivatives in water...
March 12, 2018: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Lu Li, Hai-Dong Fu
Neutrophil extracellular traps (NETs) represent a form of cell death distinct from apoptosis or necrosis. The imbalance between the formation and degradation of NETs has long been considered to be closely associated with the activity of autoimmune diseases such as systemic lupus erythematous (SLE). Reactive oxygen species derived from the nicotinamide adenine dinucleotide phosphate oxidase pathway or mitochondrial DNA pathway play a key role in the primary stage of NETs formation. The exposure or delayed degradation of abundant autoantigens, such as double-strand DNA, caused by abnormal activation of neutrophils can induce autoantibody to form immune complexes that deposit in local tissues and then induce the plasmacytoid dendritic cells to secrete the interferon alpha and other inflammatory factors...
March 2018: Zhongguo Dang Dai Er Ke za Zhi, Chinese Journal of Contemporary Pediatrics
Hiroaki Sawamoto, Yuuki Arai, Shuhei Yamakoshi, Satoshi Obika, Eiji Kawanishi
A transglycosylation reaction of 2'-amino-locked nucleic acid (LNA) from thymine (T) to other nucleobases adenine (A), guanine (G), and 5-methylcytosine (m C) has been developed. This reaction proceeds in high yield and with high β-selectivity. The mild reaction conditions enable the coexistence of acid-labile protecting groups, including a 4,4'-dimethoxytrytyl (DMTr) group. 2'-Amino-LNAs bearing any nucleobase can now be easily synthesized.
March 12, 2018: Organic Letters
Ying Huang, Gui-Quan Cai, Jian-Ping Peng, Chao Shen
Based on the results from our previous study, dexamethasone (Dex) increases reactive oxygen species (ROS) levels and subsequently induces cell death and matrix catabolism in chondrocytes. Nevertheless, the mechanism underlying this phenomenon remains unclear. Nicotinamide adenine dinucleotide (phosphate) (NADPH) oxidase 4 (NOX4) is one of the major enzymes responsible for intracellular ROS production during the inflammatory process. The objective of the current study was to investigate the role of NOX4 in Dex-induced ROS over-production...
March 8, 2018: Journal of Steroid Biochemistry and Molecular Biology
Yeji Sung, Konstantina Spagou, Marina Kafeza, Michael Kyriakides, Brahman Dharmarajah, Joseph Shalhoub, Jose A Diaz, Thomas W Wakefield, Elaine Holmes, Alun H Davies
OBJECTIVES: Deep vein thrombosis (DVT) is a major health problem, responsible for significant morbidity and mortality. The identification of a simple and effective diagnostic biomarker of DVT remains a challenge. Metabolomics have recently emerged as a new powerful scientific tool to characterise metabolic phenotypes of complex diseases and investigate small molecules in biofluids. The aim of the study was to identify the blood and vein wall metabolomic signature of DVT in a murine experimental model...
March 8, 2018: European Journal of Vascular and Endovascular Surgery
Filipa V Sena, Filipe M Sousa, A Sofia F Oliveira, Cláudio M Soares, Teresa Catarino, Manuela M Pereira
Type-II NADH:quinone oxidoreductases (NDH-2s) are membrane proteins involved in respiratory chains and the only enzymes with NADH:quinone oxidoreductase activity expressed in Staphylococcus aureus (S. aureus), one of the most common causes of clinical infections. NDH-2s are members of the two-Dinucleotide Binding Domains Flavoprotein (tDBDF) superfamily, having a flavin adenine dinucleotide, FAD, as prosthetic group and NAD(P)H as substrate. The establishment of a Charge-Transfer Complex (CTC) between the isoalloxazine ring of the reduced flavin and the nicotinamide ring of NAD+ in NDH-2 was described, and in this work we explored its role in the kinetic mechanism using different electron donors and electron acceptors...
February 17, 2018: Redox Biology
Yuria Shinohara, Mitsutoshi Tsukimoto
Damaged tissues and cells release intracellular purine nucleotides, which serve as intercellular signaling factors. We previously showed that exogenously added adenine nucleotide (250 μM ATP) suppressed the activation of murine splenic T lymphocytes. Here, we examined the effects of other purine nucleotides/nucleosides on mouse T cell activation. First, we found that pretreatment of mouse spleen T cells with 250 μM GTP, GDP, GMP, guanosine, ITP, IDP, IMP or inosine significantly reduced the release of stimulus-inducible cytokine IL-2...
March 7, 2018: Biochemical and Biophysical Research Communications
Kang-Yi Su, Liang-In Lin, Steven D Goodman, Rong-Syuan Yen, Cho-Yuan Wu, Wei-Chen Chang, Ya-Chien Yang, Wern-Cherng Cheng, Woei-Horng Fang
Deamination of adenine can occur spontaneously under physiological conditions to generate the highly mutagenic lesion, deoxyinosine (hypoxanthine deoxyribonucleotide, dI). In DNA, dI preferably pairs with cytosine rather than thymine and results in A:T to G:C transition mutations after DNA replication. The deamination of adenine is enhanced by ROS from exposure of DNA to ionizing radiation, UV light, nitrous acid, or heat. In Escherichia coli, dI repair is initiated by endonuclease V (endo V; nfi gene product) nicking but a complete repair mechanism has yet to be elucidated...
February 17, 2018: DNA Repair
Micah J McCauley, Leah Furman, Catherine A Dietrich, Ioulia Rouzina, Megan E Núñez, Mark C Williams
One of the most common DNA lesions is created when reactive oxygen alters guanine. 8-oxo-guanine may bind in the anti-conformation with an opposing cytosine or in the syn-conformation with an opposing adenine paired by transversion, and both conformations may alter DNA stability. Here we use optical tweezers to measure the stability of DNA hairpins containing 8-oxoguanine (8oxoG) lesions, comparing the results to predictive models of base-pair energies in the absence of the lesion. Contrasted with either a canonical guanine-cytosine or adenine-thymine pair, an 8oxoG-cytosine base pair shows significant destabilization of several kBT...
March 7, 2018: Nucleic Acids Research
Kosei Shibata, Yusuke Nakasone, Masahide Terazima
Blue-light-regulated phosphodiesterase 1 (BlrP1) is a blue light sensor protein that controls the hydrolysis of cyclic dimeric guanosine monophosphate, which regulates cellular motility, virulence, and formation of biofilms. In this report, the photoreaction dynamics of BlrP1 and its blue light sensor using a flavin adenine dinucleotide (BLUF) domain were investigated by the time-resolved transient grating method. Only a minor conformational change of the BlrP1-BLUF domain was observed. In contrast, a significant conformational change of the full-length BlrP1 was detected as a diffusion change with a time constant of 21 ms...
March 8, 2018: Physical Chemistry Chemical Physics: PCCP
Megan J Maher, Anuradha S Herath, Saumya R Udagedara, David A Dougan, Kaye N Truscott
Succinate:quinone oxidoreductase (SQR) functions in energy metabolism, coupling the tricarboxylic acid cycle and electron transport chain in bacteria and mitochondria. The biogenesis of flavinylated SdhA, the catalytic subunit of SQR, is assisted by a highly conserved assembly factor termed SdhE in bacteria via an unknown mechanism. By using X-ray crystallography, we have solved the structure of Escherichia coli SdhE in complex with SdhA to 2.15-Å resolution. Our structure shows that SdhE makes a direct interaction with the flavin adenine dinucleotide-linked residue His45 in SdhA and maintains the capping domain of SdhA in an "open" conformation...
March 7, 2018: Proceedings of the National Academy of Sciences of the United States of America
Luis Rajman, Karolina Chwalek, David A Sinclair
Nicotinamide adenine dinucleotide (NAD), the cell's hydrogen carrier for redox enzymes, is well known for its role in redox reactions. More recently, it has emerged as a signaling molecule. By modulating NAD+ -sensing enzymes, NAD+ controls hundreds of key processes from energy metabolism to cell survival, rising and falling depending on food intake, exercise, and the time of day. NAD+ levels steadily decline with age, resulting in altered metabolism and increased disease susceptibility. Restoration of NAD+ levels in old or diseased animals can promote health and extend lifespan, prompting a search for safe and efficacious NAD-boosting molecules that hold the promise of increasing the body's resilience, not just to one disease, but to many, thereby extending healthy human lifespan...
March 6, 2018: Cell Metabolism
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