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Nelisiwe Khuzwayo, Myra Taylor
BACKGROUND: Prevention of youth sexual risk behaviour among the youth in uMgungundlovu District Municipality continues to be a primary challenge for public health and health promotion. Current prevention interventions are targeted at an individual level, whilst youth behaviour is influenced by many social and environmental factors. AIM: The aim of the study was to explore the factors influencing sexual risk behaviours of the youth at different socio-ecological levels in uMgungundlovu District Municipality...
March 7, 2018: African Journal of Primary Health Care & Family Medicine
Hongxia Liao, Ying Zhou, Yaqin Chai, Ruo Yuan
Herein, we constructed an ultrasensitive electrochemiluminescence (ECL) biosensor for detecting microRNA-21 (miR-21) based on in-situ generation of copper nanoclusters (Cu NCs) as luminophore and titanium dioxide (TiO2 ) as coreaction accelerator. First, numerous AT-rich double-stranded DNA (dsDNA) was produced from the conversion of a small amount of target miR-21 via the combination of exonuclease III (Exo III)-assisted amplification and hybridization chain reaction (HCR), which could reduce the aggregation-caused self-etching effect of Cu NCs and improve the emitting of Cu NCs...
May 8, 2018: Biosensors & Bioelectronics
Ning Xu, Lili Wang, Junjie Guan, Chao Tang, Ning He, Wei Zhang, Shiping Fu
One homogeneous polysaccharide (ZWP) was successfully isolated and purified from the rhizomes of Curcuma zedoaria and the aim of present study was to determine the potential of chitosan/silk hydrogel sponge loaded with platelet-rich plasma exosomes (PRP-Exos), ZWP or PRP-Exos/ZWP on wound-healing in diabetic rats. An in vivo diabetic wound healing study showed that separate or combined treatments all resulted in a wound contraction in diabetic rats, as evidenced by a decrease of ulcer and an increase of epidermal thickness, but PRP-Exos/ZWP combination therapy was more successful in wound closing than either PRP-Exos or ZWP single administration...
May 14, 2018: International Journal of Biological Macromolecules
Haythem Latif, Stephen Federowicz, Ali Ebrahim, Janna Tarasova, Richard Szubin, Jose Utrilla, Karsten Zengler, Bernhard O Palsson
Numerous in vitro studies have yielded a refined picture of the structural and molecular associations between Cyclic-AMP receptor protein (Crp), the DNA motif, and RNA polymerase (RNAP) holoenzyme. In this study, high-resolution ChIP-exonuclease (ChIP-exo) was applied to study Crp binding in vivo and at genome-scale. Surprisingly, Crp was found to provide little to no protection of the DNA motif under activating conditions. Instead, Crp demonstrated binding patterns that closely resembled those generated by σ70...
2018: PloS One
Lin-Su Wei, Guo-Xue He, Xiang-Fei Kong, Cheng-Xue Pan, Dong-Liang Mo, Gui-Fa Su
A series of 1,2- and 2,3-fused quinazolinones have been synthesized in good to excellent yields through gold-catalyzed selective hydroarylations of alkynyl quinazolinone-tethered pyrroles. The studies revealed that 1,2-fused quinazolinones were obtained through a 1,3-rearrangement and sequential 6-exo-trig cyclization of N1-alkynyl quinazolinone-tethered pyrroles while N3-alkynyl quinazolinone-tethered pyrroles went through 6-exo-dig or 7-endo-dig cyclizations directly to afford 2,3-fused quinazolinones. The fused quinazolinones could be prepared at gram scale in three steps from commercial ortho-aminobenzamide...
May 17, 2018: Journal of Organic Chemistry
Alexander N Morozov, Alexander Moiseevich Mebel, Ralf I Kaiser
Theoretical calculations of the rate constants and product branching ratios in the pyrolysis of exo-tetrahydrodicyclopentadiene (JP-10) and its initial decomposition products at combustion-relevant pressures and temperatures have been performed and compared to the experimental results from the recently reported molecular beam photoionization mass spectrometry study of the pyrolysis of JP-10 (Zhao, L.; Yang, T.; Kaiser, R. I.; Troy, T. P.; Xu, B.; Ahmed, M.; Alarcon, J.; Belisario-Lara, D.; Mebel, A. M.; Zhang, Y...
May 17, 2018: Journal of Physical Chemistry. A
Qingling Liu, Li Li, Yan Zhao, Zhengbo Chen
The authors describe a colorimetric method for the determination of DNA based on the deaggregation of gold nanoparticles (AuNPs) induced by exonuclease III (Exo III). DNA amplification is accomplished by Exo III to generate large quantities of the residual DNA. Residual DNA tethers onto the surfaces of AuNPs which prevents their aggregation. Hence, the color of the solution is red. However, in the absence of DNA, salt-induced aggregation is not prevented, and the bluish-purple color of the aggregated AuNPs is observed...
May 15, 2018: Mikrochimica Acta
Hisaka Shimizu, Masahiro Nakajima, Akimasa Miyanaga, Yuta Takahashi, Nobukiyo Tanaka, Kaito Kobayashi, Naohisa Sugimoto, Hiroyuki Nakai, Hayao Taguchi
β-1,2-Glucan is a polysaccharide produced mainly by some Gram-negative bacteria as a symbiosis and infectious factor. We recently identified endo-β-1,2-glucanase from Chitinophaga pinensis ( CpSGL) as an enzyme comprising a new family. Here, we report the characteristics and crystal structure of a CpSGL homolog from Parabacteroides distasonis, an intestinal bacterium (BDI_3064 protein), which exhibits distinctive properties of known β-1,2-glucan-degrading enzymes. BDI_3064 hydrolyzed linear β-1,2-glucan and β-1,2-glucooligosaccharides with degrees of polymerization (DP) of 4 or more to produce sophorose specifically, but did not hydrolyze cyclic β-1,2-glucan...
May 15, 2018: Biochemistry
Dongmin Shi, Feifan Sheng, Xiaojun Zhang, Guangfeng Wang
This paper reported a novel colorimetric assay strategy for avidin and biotin interactions based on terminal protection of the biotinylated single-stranded DNA and the surface plasmon resonance adsorption of gold nanoparticles (AuNPs). In this assay, it was firstly found that biotin-ssDNA specifically bound to the target protein avidin with strong affinity could be protected from hydrolysis by exonuclease I (Exo I). Furthermore, a colorimetric strategy was designed for the detection of avidin and biotin interactions...
August 1, 2018: Talanta
Nina B Melnikova, Darina S Malygina, Irina N Klabukova, Denis V Belov, Viktor A Vasin, Pavel S Petrov, Alexander V Knyazev, Alexey V Markin
Betulin-3,28-diphosphate (BDP) obtained by phosphorylation of betulin using POCl₃ has two main structural forms-BDP-1 and BDP-2-which differ in ethanol solubility, melting point, FTIR spectra, thermoanalytical characteristics and biological activity. Betulin-3,28-diphosphate and its sodium salt (Na-BDP) were characterized using 13 C and 31 P-NMR spectra, powder XRD experiments, as well as differential scanning calorimetry (DSC) and thermogravimetric analysis (TG) methods. The exo-effects at 193 ± 8 °C for ethanol soluble BDP-1 samples (-19...
May 14, 2018: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Sirajul Salekin, Jianqiu Michelle Zhang, Yufei Huang
Motivation: Transcription factor (TF) binds to the promoter region of a gene to control gene expression. Identifying precise transcription factor binding sites (TFBS) is essential for understanding the detailed mechanisms of TF mediated gene regulation. However, there is a shortage of computational approach that can deliver single base pair (bp) resolution prediction of TFBS. Results: In this paper, we propose DeepSNR, a Deep Learning algorithm for predicting transcription factor binding location at Single Nucleotide Resolution de novo from DNA sequence...
May 10, 2018: Bioinformatics
Fen Xu, Wei-Fen Kang, Yang Wang, Chun-Sen Liu, Jia-Yue Tian, Rui-Rui Zhao, Miao Du
The catalytic [5 + 1] annulation/5-exo-cyclization reaction of amidines with diynes is reported herein. This protocol provides highly atom-economical access to fabricate two nitrogen-containing heterocycles in one step with high efficiency and selectivity. Significantly, this reaction represents the first example of using diyne as a one-carbon reaction partner in C-H functionalization. Kinetic isotope effects suggested that the catalytic cycle of this reaction is initiated by the cleavage of the ortho C-H bond in the N-phenyl ring of amidines, which is likely involved in the rate-limiting step...
May 14, 2018: Organic Letters
Marco Tucci, Francesco Mannavola, Anna Passarelli, Luigia Stefania Stucci, Mauro Cives, Franco Silvestris
Exosomes (Exo) are small vesicles produced by melanoma cells and the accessory cells of the tumor microenvironment. They emerge via both classical and direct pathways and actively participate in tumor colonisation of distant tissues. The proteins, nucleic acids, cytokines and growth factors engulfed by Exo are transferred to recipient cells, where they drive numerous functions required for the tumor escape from immune system control and tumor progression. By positively or negatively modulating immune cell properties, Exo provoke immune suppression and, in turn, defective dendritic cell (DC) functions...
April 17, 2018: Oncotarget
Helia Namazi, Iman Namazi, Parisa Ghiasi, Hassan Ansari, Sarah Rajabi, Ensiyeh Hajizadeh-Saffar, Nasser Aghdami, Elham Mohit
Cardiosphere-derived cells (CDCs) have emerged as one of the most promising stem cell types for cardiac protection and repair. Exosomes are required for the regenerative effects of human CDCs and mimic the cardioprotective benefits of CDCs such as anti-apoptotic effect in animal myocardial infarction (MI) models. Here we aimed to investigate the anti-apoptotic effect of the hypoxic and normoxic human CDCs-derived exosomes on induced apoptosis in human embryonic stem cell-derived cardiomyocytes (hESC-CMs). In this study, CDCs were cultured under normoxic (18% O2 ) and hypoxic (1% O2 ) conditions and CDC-exosomes were isolated from conditioned media by differential ultracentrifugation...
2018: Iranian Journal of Pharmaceutical Research: IJPR
Shunbi Xie, Ying Tang, Dianyong Tang, Yanhua Cai
In this work, a highly sensitive impedimetric biosensor was developed for mercuric ion (Hg2+ ) detection. The biosensor design was based on Hg2+ -triggered exonuclease III (Exo III) cleavage for target recycling and DNAzyme-mediated catalytic for precipitation polymerization. Hg2+ induced thymine-thymine (T-T) mismatches were used to trigger the Exo III-catalyzed target recycling and produce free single-stranded DNA (defined as M). The outputted M then assisted the in formation of a DNA network on electrode surface to efficiently immobilize the porphyrin manganese (MnTmPyP)...
September 6, 2018: Analytica Chimica Acta
Li Tengda, Long Shuping, Gu Mingli, Guo Jie, Liu Yun, Zhang Weiwei, Deng Anmei
Exosomes are small homogenous membrane vesicles that derive from the exocytosis process of cells and can contain DNA, microRNAs (miRNAs), and/or proteins. Characterization of the content profile of exosomes may reflect the state of the cells that release them, and this could be predictive of disease. In this study, to explore the potential biomarkers for melanoma, we isolated serous exosomes from 30 patients with melanoma and 30 healthy individuals using the ultracentrifugation method. Five miRNAs were subsequently detected in each sample by quantitative reverse transcription-PCR: miRNA-532-5p, miRNA-106b, miRNA-200c, miRNA-199a-5p, and miRNA-210...
May 10, 2018: Melanoma Research
Ravikumar A, Panneerselvam P
We describe a highly sensitive fluorescence biosensor incorporating polydopamine nanotubes (PDNTs) based on the mechanism of exonuclease III (Exo III) assisted signal amplification for the determination of Hg2+ in aqueous solution. Fluorescent probes of FAM labeled ssDNA (FAM-ssDNA) adsorbed on the PDNTs act as an efficient quencher. In the presence of Hg2+, the FAM-ssDNA can bind to Hg2+ to form double stranded DNA (dsDNA) via the formation of T-Hg2+-T base pairs. Then, the dsDNA was removed from the surface of the PDNTs to restore the fluorescence...
May 11, 2018: Analyst
Sipeng Lin, Chao Xu, Daoling Peng, Liang Peng, Dingqiao Yang, Yuhua Long, Yu Chang, Feng Long Gu
The mechanism of an asymmetric ring-opening (ARO) addition of oxabicyclic alkenes catalyzed by a platinum(ii) catalyst was investigated by M06-2X/6-311G(d,p) using density functional theory (DFT). All the structures were optimized in the solvent model density (SMD) solvation model (solvation = the mixture of H2O/CH2Cl2 1 : 10, v/v) for consistence with experimental conditions. The overall mechanism is considered as a four-step reaction including transmetalation, carboplatinum, β-oxygen elimination, and hydrolysis...
May 11, 2018: Physical Chemistry Chemical Physics: PCCP
Yanyang Chen, Yasaman Jami-Alahmahdi, Kiran Sagar Unikela, Graham J Bodwell, Travis D Fridgen
1,1,9,9-Tetramethyl[9](2,11)teropyrenophane (TM9TP), a belt-shaped molecule, has a sizable cavity that molecules or ions could occupy. In this study, the question of whether TM9TP forms gas phase ion-molecule complexes with metal cations (K+, Rb+, Cs+) situated inside or outside the TM9TP cavity was addressed using both experimental and computational methods. Complexes were trapped in a Fourier transform ion cyclotron resonance mass spectrometer and their structures were explored by some novel physical chemistry/mass spectrometry methods...
May 9, 2018: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
Liya Zhu, Ji Min Oh, Prakash Gangadaran, Senthilkumar Kalimuthu, Se Hwan Baek, Shin Young Jeong, Sang-Woo Lee, Jaetae Lee, Byeong-Cheol Ahn
Objective: Glioblastoma is a highly aggressive primary brain tumor that is resistant to radiotherapy and chemotherapy. Natural killer (NK) cells have been used to treat incurable cancers. Recent studies have investigated the effectiveness of NK-cell-derived exosomes (NK-Exo) for treating incurable cancers such as melanoma, leukemia, and neuroblastoma; however, NK-Exo have not been used to treat glioblastoma. In the present study, we investigated the antitumor effects of NK-Exo against aggressive glioblastoma both in vitro and in vivo and determined the tumor-targeting ability of NK-Exo by performing fluorescence imaging...
2018: Frontiers in Immunology
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