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Jorge Casinhas, Rute G Matos, Nabila Haddad, Cecília M Arraiano
Bacteria need to promptly respond to environmental changes. Ribonucleases (RNases) are key factors in the adaptation to new environments by enabling a rapid adjustment in RNA levels. The exoribonuclease polynucleotide phosphorylase (PNPase) is essential for low-temperature cell survival, affects the synthesis of proteins involved in virulence and has an important role in swimming, cell adhesion/invasion ability, and chick colonization in C. jejuni. However, the mechanism of action of this ribonuclease is not yet known...
January 12, 2018: Biochimie
Bingqing Shui, Dan Tao, Anca Florea, Jing Cheng, Qin Zhao, Yingying Gu, Wen Li, Nicole Jaffrezic-Renault, Yong Mei, Zhenzhong Guo
Alzheimer's disease (AD) is a chronic disease amongst people aged 65 and older. Increasing evidence has illustrated that early diagnosis holds the key to effective treatment of AD. A variety of detection techniques have been developed. Biosensors are excellent analytical tools which have applications in detecting the biomarkers of AD. This review includes appropriate bioreceptors to achieve highly sensitive and selective quantification of AD biomarkers by using transducers. AD biomarkers such as tau protein, amyloid β peptides and apolipoprotein E4, are firstly summarized...
January 4, 2018: Biochimie
Zheng-Yuan Xie, Zhi-Hua Xiao, Fen-Fen Wang
BACKGROUND: Numerous documents have indicated a critical role of autophagy in alcoholic liver fibrosis (ALF), but few papers have reported its function in hepatic stellate cells (HSCs) activation. The current study aimed to investigate the regulation effect of autophagy in HSCs activation, in further to explore the underlying mechanism involved. METHODS: HSC-T6 cells were treated with ethanol, 3-MA (autophagy inhibitor) or rapamycin (autophagy inducer), and cells were also transfected with si-Nrf2 or si-Keap1...
January 2, 2018: Biochimie
Nikolay Barinov, Nikita Ivanov, Alexey Kopylov, Dmitry Klinov, Elena Zavyalova
High-resolution atomic force microscopy (AFM) is a powerful technique for the direct visualization of single molecules. Here, AFM is applied to characterize the oligomeric state of hemagglutinins of the influenza virus. Hemagglutinins are known to be present in a trimeric form inside the viral envelope. However, recombinant hemagglutinins are also present as large oligomers, which impair the functional activity of the protein. Five commercial recombinant hemagglutinins from the viral strains H1, H3, H5, H7, and H9 were studied with high-resolution AFM...
January 2, 2018: Biochimie
Zhenyu Zou, Siying Wu, Jingyuan Xiong, Huangyuan Li, Yiguo Jiang, Huidong Zhang
The hybridization of two complementary ssDNA is essential for molecular biology and biological physics. T7 ssDNA binding protein (gp2.5) can rapidly facilitate this hybridization, but the mechanism and kinetic process remain unknown. As determined by fluorescence resonance energy transfer (FRET) and rapid kinetic analysis methods, gp2.5 binding coiling ssDNA to form gp2.5-ssDNA complex is the rate-limiting step for the entire DNA hybridization process. Afterward, the hybridization initiates from either the terminus or the internal part of ssDNA at a nucleation rate of 0...
December 29, 2017: Biochimie
A I Osipyants, A A Poloznikov, N A Smirnova, D M Hushpulian, A Yu Khristichenko, T A Chubar, A A Zakhariants, M Ahuja, I N Gaisina, B Thomas, A M Brown, I G Gazaryan, V I Tishkov
L-Ascorbate (L-Asc), but not D-isoascorbate (D-Asc) and N-acetylcysteine (NAC) suppress HIF1 ODD-luc reporter activation induced by various inhibitors of HIF prolyl hydroxylase (PHD). The efficiency of suppression by L-Asc was sensitive to the nature of HIF PHD inhibitor chosen for reporter activation. In particular, the inhibitors developed to compete with alpha-ketoglutarate (αKG), were less sensitive to suppression by the physiological range of L-Asc (40-100 μM) than those having a strong iron chelation motif...
December 28, 2017: Biochimie
José Bubis, Juan Carlos Martínez, Maritza Calabokis, Joilyneth Ferreira, Carlos E Sanz-Rodríguez, Victoria Navas, José Leonardo Escalona, Yurong Guo, Susan S Taylor
The full gene sequence encoding for the Trypanosoma equiperdum ortholog of the cAMP-dependent protein kinase (PKA) regulatory (R) subunits was cloned. A poly-His tagged construct was generated [TeqR-like(His)8], and the protein was expressed in bacteria and purified to homogeneity. The size of the purified TeqR-like(His)8 was determined to be ∼ 57,000 Da by molecular exclusion chromatography indicating that the parasite protein is a monomer. Limited proteolysis with various proteases showed that the T. equiperdum R-like protein possesses a hinge region very susceptible to proteolysis...
December 27, 2017: Biochimie
Rui Yang, Guojun Zhang, Furui Zhang, Zhanjiang Li, Chun Huang
The structural dynamics of membrane permeabilization are investigated systematically and compared between viral fusion peptides (VFPs) and antimicrobial peptides (AMPs). It is revealed that the permeabilization process can be divided into two phases: a fast motion phase in water (first phase) and a slow diffusion phase in lipid (second phase). Difference in peptide permeability to neutrally or weakly charged mammalian membrane and to negatively charged bacterial membrane is primarily determined by the first phase, which is dominated by the direct electrostatic interaction between peptide and the hydrophilic surface of membranes...
December 22, 2017: Biochimie
Carolyn E Carr, Rajkumar Ganugula, Ronald Shikiya, Ana Maria Soto, Luis A Marky
Oligonucleotide-directed triple helix formation has been recognized as a potential tool for targeting genes with high specificity. Cystosine methylation in the 5' position is both ubiquitous and a stable regulatory modification, which could potentially stabilize triple helix formation. In this work, we have used a combination of calorimetric and spectroscopic techniques to study the intramolecular unfolding of four triplexes and two duplexes. We used the following triplex control sequence, named Control Tri, d(AGAGAC5TCTCTC5TCTCT), where C5 are loops of five cytosines...
December 22, 2017: Biochimie
Yoshikazu Nakamura
No abstract text is available yet for this article.
December 22, 2017: Biochimie
Ana Crnković, Mirela Čavužić, Vlatka Godinić-Mikulčić, Gregor Anderluh, Ivana Weygand-Đurašević, Ita Gruić-Sovulj
Aminoacyl-tRNA synthetases (aaRS) decode genetic information by coupling tRNAs with cognate amino acids. In the archaeon Methanothermobacter thermautotrophicus arginyl- and seryl-tRNA synthetase (ArgRS and SerRS, respectively) form a complex which enhances serylation and facilitates tRNASer recycling through its association with the ribosome. Yet, the way by which complex formation participates in Arg-tRNAArg synthesis is still unresolved. Here we utilized pull down and surface plasmon resonance experiments with truncated ArgRS variants to demonstrate that ArgRS uses its N-terminal domain to establish analogous interactions with both SerRS and cognate tRNAArg, providing a rationale for the lack of detectable SerRS•[ArgRS•tRNAArg] complex...
December 19, 2017: Biochimie
Nele Aas-Valleriani, Tõnu Reintamm, Merike Kelve
Deoxynucleoside 5-monophosphate N-glycosidase or DNPH1 (former name Rcl) is a nucleotide hydrolase whose expression in mammalian cancer tissues has been associated with its tumorigenic potential. Therefore, the enzyme has been studied principally in rat and human models. We found the corresponding gene also in the freshwater sponge Ephydatia muelleri, an animal phylogenetically very distant from mammals. Here we report the expression and characterization of the recombinant DNPH1 from E. muelleri. The ancient homolog of mammalian enzyme in a sponge showed the substrate specificity and catalytic efficiency similar to that in higher animals...
December 19, 2017: Biochimie
Melike Yuksel, Kevser Biberoglu, Seda Onder, K Gonca Akbulut, Ozden Tacal
Recently, we demonstrated that toluidine blue O (TBO), a phenothiazine dye, shows inhibitory effects on both cholinesterases and amyloid pathology in Alzheimer's disease (AD) cellular model. In the present study, we aimed to determine the effects of TBO (in a purity of 85%) on amyloid and tau pathologies in a triple transgenic mouse model of AD (3xTg-AD). Beginning at 7.5 (mild pathology) or 13 (severe pathology) months of age, 3xTg-AD mice were treated intraperitoneally with 4 mg/kg TBO or vehicle daily for 30 days...
December 14, 2017: Biochimie
Federico M Ruiz, Ulrich Gilles, Anna-Kristin Ludwig, Celia Sehad, Tze Chieh Shiao, Gabriel García Caballero, Herbert Kaltner, Ingo Lindner, René Roy, Dietmar Reusch, Antonio Romero, Hans-Joachim Gabius
Despite its natural abundance in lenses of vertebrates the physiological function(s) of the galectin-related inter-fiber protein (GRIFIN) is (are) still unclear. The same holds true for the significance of the unique interspecies (fish/birds vs mammals) variability in the capacity to bind lactose. In solution, ultracentrifugation and small angle X-ray scattering (at concentrations up to 9 mg/mL) characterize the protein as compact and stable homodimer without evidence for aggregation. The crystal structure of chicken (C-)GRIFIN at seven pH values from 4...
December 14, 2017: Biochimie
Saoussen Ben Ayed, Madiha Bou Ali, Aymen Bali, Youssef Gargouri, Dhafer Laouini, Yassine Ben Ali
Leishmaniasis is a parasitic reticuloendotheliosis whose pathogen is a zooflagellate belonging to the genus Leishmania transmitted by the bite of an infected phlebotome. Recently, a unique secretory lipase from the human pathogen Leishmania donovani Ldlip3 has been identified and characterized. This lipase has a high identity with a putative triacylglycerol lipase of Leishmania major (Lmlip2). In the present study, Lmlip2 was expressed in the eukaryotic heterologous expression system Pichia pastoris as tagged enzyme of 308 amino acids...
December 12, 2017: Biochimie
Justin Liam Henri, Joanna Macdonald, Mia Strom, Wei Duan, Sarah Shigdar
Current therapy for ovarian cancer typically involves indiscriminate chemotherapies that can have severe off target effects on healthy tissue and are still plagued by aggressive recurrence. Recent shifts towards targeted therapies offer the possibility of circumventing the obstacles experienced by these traditional treatments. While antibodies are the pioneering agents in targeted therapies, clinical experience has demonstrated that their antitumor efficacy is limited due to their high immunogenicity, large molecular size, and costly and laborious production...
December 7, 2017: Biochimie
Jameel Lone, Hilal Ahmad Parray, Jong Won Yun
Browning of white adipocytes (beiging) is an attractive therapeutic strategy against obesity and its associated metabolic complications. Nobiletin (NOB) is a polymethoxylated flavone present in Citrus fruits and has been reported to have anti-obesity effects. Here, we report that nobiletin exerts dual modulatory effects on adipocytes via induction of browning in 3T3-L1 white adipocytes and amelioration of stress in adipocytes. Nobiletin-induced beiging was investigated by determining expression levels of beige-specific genes and proteins by RT-PCR and immunoblot analysis, respectively...
December 4, 2017: Biochimie
Anna M Ogloblina, Alexandra N Khristich, Natalia Y Karpechenko, Svetlana E Semina, Gennady A Belitsky, Nina G Dolinnaya, Marianna G Yakubovskaya
We selected and investigated nine G-quadruplex (G4)-forming aptamers originally designed against different proteins involved in the regulation of cellular proliferation (STAT3, nucleolin, TOP1, SP1, VEGF, and SHP-2) and considered to be potential anticancer agents. We showed that under physiological conditions all the aptamers form stable G4s of different topology. G4 aptamers designed against STAT3, nucleolin and SP1 inhibit STAT3 transcriptional activity in human breast adenocarcinoma MCF-7 cells, and all the studied aptamers inhibit TOP1-mediated relaxation of supercoiled plasmid DNA...
December 2, 2017: Biochimie
Masaki Takahashi
High affinity binders targeting specific cell surface proteins are vital for developing basic and applied biosciences. However, despite sustained efforts to generate such binders by chemicals and antibodies, there are still many cell surface proteins that lack high affinity binders. Nucleic acids, referred to as aptamers, appear to be potential binders to capture cell surface proteins because single-strand DNA/RNA can form distinct structures of high affinity and specificity to a wide range of targets. Aptamers are isolated from large combinatorial libraries using a unique iterative selection-amplification process known as systematic evolution of ligands by exponential enrichment (SELEX)...
November 30, 2017: Biochimie
Angela C Mora Huertas, Christian E H Schmelzer, Chiara Luise, Wolfgang Sippl, Markus Pietzsch, Wolfgang Hoehenwarter, Andrea Heinz
Neprilysin is also known as skin fibroblast-derived elastase, and its up-regulation during aging is associated with impairments of the elastic fiber network, loss of skin elasticity and wrinkle formation. However, information on its elastase activity is still limited. The aim of this study was to investigate the degradation of fibrillar skin elastin by neprilysin and the influence of the donor's age on the degradation process using mass spectrometry and bioinformatics approaches. The results showed that cleavage by neprilysin is dependent on previous damage of elastin...
November 28, 2017: Biochimie
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