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Stefan Becker, André Scheffel, Martin F Polz, Jan-Hendrik Hehemann
Marine algae produce varieties of glycans, which fulfill diverse biological functions and fuel the carbon and energy demand of heterotrophic microbes. A common approach to analyze marine organic matter uses acid to hydrolyze its glycans into measurable monosaccharides. These, however, may derive from different glycans that are built with the same monosaccharides, hence this approach does not distinguish between glycans in natural samples. Here we use enzymes to selectively digest and thereby quantify laminarin in particulate organic matter...
February 17, 2017: Applied and Environmental Microbiology
Anindita Das, Tanya Singh, P A LokaBharathi, Prashant K Dhakephalkar, Sweta Mallik, Pranav R Kshirsagar, N H Khadge, B Nagender Nath, Satadru Bhattacharya, Aditya Kumar Dagar, Prabhjot Kaur, Dwijesh Ray, Anil D Shukla, Christabelle E G Fernandes, Sheryl O Fernandes, Tresa Remya A Thomas, Mamatha S S, Babu Shashikant Mourya, Ram Murti Meena
Red clays of Central Indian Basin (CIB) under influence of trace of Rodriguez Triple Junction exhibited chemoautotrophy, low temperature hydrothermal alterations and photoautotrophic potential. Seamount flank TVBC-08, hosting such signatures revealed dominance of aerobic anoxygenic phototroph Erythrobacter, with 93% of total 454 pyrosequencing tags. Subsequently, enrichments for both aerobic (Erythrobacter) and anaerobic anoxygenic phototrophs (green and purple sulphur bacteria) under red and white LED light illumination, with average irradiance 30...
February 2017: Life Sciences in Space Research
Yi-Chen Cheng, Ying-Yu Chen, Che-Ping Chuang
An efficient and low-cost method for the synthesis of 4-substituted quinolin-2-(1H)-ones has been developed. In the presence of TBHP, the cobalt(ii)-catalyzed carbocyclization reactions of arylethenyl substituted α-bromo-N-phenylacetamides, involving sequential 6-exo-trig radical cyclization, t-butylperoxy radical cross-coupling reaction and the base-promoted ionic Kornblum-DeLaMare reaction, produced 4-benzoylquinolin-2-(1H)-ones. A variety of useful functional groups such as methoxy, fluoro, chloro, bromo, methoxycarbonyl, and cyano groups, are compatible with the reaction conditions...
February 16, 2017: Organic & Biomolecular Chemistry
Lianbo Shao, Yu Zhang, Beibei Lan, Juanjuan Wang, Zhiwei Zhang, Lulu Zhang, Pengli Xiao, Qingyou Meng, Yong-Jian Geng, Xi-Yong Yu, Yangxin Li
Mesenchymal stem cells (MSCs) repair infarcted heart through paracrine mechanism. We sought to compare the effectiveness of MSCs and MSC-derived exosomes (MSC-Exo) in repairing infarcted hearts and to identify how MSC-Exo mediated cardiac repair is regulated. In a rat myocardial infarction model, we found that MSC-Exo inhibited cardiac fibrosis, inflammation, and improved cardiac function. The beneficial effects of MSC-Exo were significantly superior compared to that of MSCs. To explore the potential mechanisms underlying MSC-Exo's effects, we performed several in vitro experiments and miRNA-sequence analysis...
2017: BioMed Research International
Ling-Ling Zheng, Kai-Wen Deng, An-Cheng Deng, Jie Wu, Jian-Hua Yang, Zhao-Rong Lun, Liang-Hu Qu
MicroRNAs (miRNAs) are small regulatory RNAs that play important roles in animals, plants, and viruses. Deep-sequencing technology has been widely adopted in miRNA investigations. However, it is still a big mysterious why nearly all sequencing data contain miRNA sequences from exogenous species, called exo-miRNAs. In this study, we developed a novel platform, exo-miRExplorer, for mining and identifying exo-miRNAs from high-throughput small RNA sequencing experiments which originated from tissues and cell lines of multiple organisms...
2017: Frontiers in Microbiology
J Rose Stoller, Kurt Wagschal, Charles C Lee, Douglas B Jordan
We recently reported on the kinetics of the polygalacturonase TtGH28 acting on trimer and dimer substrates. When the starting substrate for hydrolysis is the trimer, the product dimer is also subject to hydrolysis, resulting in discrepancies when either the concentration of dimer or monomer product is used for analysis of trimer hydrolysis. Here, we derive a method for determining catalytic rates of exo-hydrolases acting on trimer (and higher order) substrates when products may also be substrates for hydrolysis and show how this correction may be applied for TtGH28...
February 12, 2017: Analytical Biochemistry
Laura M M Pascual, Adam E Goetz, Adrienne M Roehrich, Andrew J Boydston
This study investigated the microstructures of polymers produced via photoredox-mediated metal-free ring-opening metathesis polymerization. Polynorbornene, poly(exo-dihydrodicyclopentadiene), and poly(endo-dicyclopentadiene) were found to have cis olefin contents of 23%, 24%, and 28%, respectively. Additionally, the cis/trans ratio remained consistent during the course of norbornene polymerization. Polymer tacticity was evaluated by quantitative (13) C NMR spectroscopy, which revealed each polymer to be largely atactic...
February 13, 2017: Macromolecular Rapid Communications
Xiaoyi Gao, Mingxi Geng, Yunchao Li, Xinglin Wang, Hua-Zhong Yu
Herein, we report a combined electrochemical and ESI-MS study of the enzymatic hydrolysis efficiency of DNA self-assembled monolayers (SAMs) on gold, platform systems for understanding nucleic acid surface chemistry, and for constructing DNA-based biosensors. Our electrochemical approach is based on the comparison of the amounts of surface-tethered DNA nucleotides before and after exonuclease I (Exo I) incubation using electrostatically bound [Ru(NH3)6](3+) as redox indicators. It is surprising to reveal that the hydrolysis efficiency of ssDNA SAMs does not depend on the packing density and base sequence, and that the cleavage ends with surface-bound shorter strands (9-13 mers)...
February 9, 2017: Analytical Chemistry
Jun Onagi, Toru Komatsu, Yuki Ichihashi, Yugo Kuriki, Mako Kamiya, Takuya Terai, Tasuku Ueno, Kenjiro Hanaoka, Hiroyuki Matsuzaki, Keisuke Hata, Toshiaki Watanabe, Tetsuo Nagano, Yasuteru Urano
Cellular homeostasis is maintained by a complex network of reactions catalyzed by enormous numbers of enzymatic activities (the enzymome), which serve to determine the phenotypes of cells. Here, we focused on the enzymomics of proteases and peptidases, because these enzymes are an important class of disease-related proteins. We describe a system that (A) simultaneously evaluates metabolic activities of peptides using series of exogenous peptide substrates and (B) identifies the enzymes that metabolize the specified peptide substrate with high throughput...
February 13, 2017: Journal of the American Chemical Society
Zuxiao Zhang, Henry Martinez, William R Dolbier
The first example of photo-redox catalyzed difluoromethylation of unactivated alkenes coupled with C-C bond formation to an aryl ring is reported. The reactions are conducted under mild conditions and afford tetralin derivatives bearing difluoromethyl as well as other fluoroalkyl groups in good to high yields. In addition, the study indicates that 6-exo radical cyclization of an alkyl radical to a phenyl ring is faster than the respective 5-exo radical cyclization. A computational study provides insights to the experimental results...
February 10, 2017: Journal of Organic Chemistry
Marion C Hoepflinger, Margit Hoeftberger, Aniela Sommer, Christina Hametner, Ilse Foissner
Charasomes are convoluted plasma membrane domains in characean green algae. They are known to form in response to light via secretion of trans-Golgi network (TGN) vesicles and local inhibition of endocytosis. Charasomes are involved in the acidification of their aqueous environment, thereby facilitating photosynthesis-dependent carbon uptake. Charasome formation is reversible to allow cells to adapt to different light conditions. Here, we show that darkness-induced degradation of charasomes involves the formation of coated pits and coated vesicles...
2017: Frontiers in Plant Science
Tengku Ain Kamalden, Anne M Macgregor-Das, Sangeetha M Kannan, Brittany Dunkerly-Eyring, Nurliza Khaliddin, Zhenhua Xu, Anthony P Fusco, Syatirah Abu Yazib, Rhuen Chiou Chow, Elia J Duh, Marc K Halushka, Charles Steenbergen, Samarjit DAS
AIMS: Mi(cro)RNAs, one type of non-coding RNA, modulate post-transcriptional gene expression in various pathogenic pathways in type-2-diabetes (T2D). Currently, little is known about how miRNAs influence disease pathogenesis by targeting cells at a distance. The purpose of this study was to investigate the role of exosomal miRNAs during T2D. RESULTS: We show that miR-15a is increased in the plasma of diabetic patients, correlating with disease severity. miR-15 plays an important role in insulin production in pancreatic-β-cells...
February 7, 2017: Antioxidants & Redox Signaling
Jie Ma, Yuanyuan Zhao, Li Sun, Xiaochun Sun, Xiaosu Zhao, Xiaoxian Sun, Hui Qian, Wenrong Xu, Wei Zhu
We have previously demonstrated the cardioprotective effects of exosomes derived from mesenchymal stem cells (MSCs). It is well known that the activation of Akt is involved in stem cell-induced cardioprotection. In the present study, we investigated whether exosomes released from Akt-overexpressing MSCs showed a beneficial effect on cardioprotection and angiogenesis. MSCs were collected from human umbilical cord (hucMSCs), and Akt was transfected into hucMSCs (Akt-hucMSCs) by using an adenovirus transfection system...
January 2017: Stem Cells Translational Medicine
Xing Tang, Arunima Srivastava, Huayang Liu, Kun Huang, Gustavo Leone
No abstract text is available yet for this article.
February 7, 2017: Bioinformatics
Peng-Hua Li, Jin-Ming Yang, Yin Wei, Min Shi
An interesting silver(I)-catalyzed, one-pot intramolecular cyclization of epoxide-propargylic esters is described. A variety of 1,4-oxazine derivatives were obtained through a novel domino sequence, including three-membered ring-opening, 3,3-sigmatropic rearrangement, 6-exo-cycloisomerization and subsequent intramolecular elimination in moderate yields under mild conditions.
February 2017: ChemistryOpen
Yan Zhang, Mei Yu, Minjia Dai, Chang Chen, Qi Tang, Wei Jing, Hang Wang, Weidong Tian
Adipose tissue is an active endocrine organ that could secrete a wide number of factors to regulate adipogenesis via paracrine signals. In addition to soluble proteins in adipose tissue, microRNAs (miRNAs) enriched in extracellular vesicles (EVs), such as exosomes or microvesicles, could modulate intercellular communications. In this study, we demonstrated that exosome-like vesicles derived from adipose tissue (Exo-AT) were internalized by adipose tissue-derived stem cells (ADSCs), then induced adipogenesis...
February 6, 2017: Journal of Cell Science
Maryam Rezaei Arjomand, Gholamreza Ahmadian, Mehran Habibi-Rezaei, Malihe Hassanzadeh, Ali Asghar Karkhane, Ali Akbar Moosavi-Movahedi, Massoud Amanlou
Here, we have studied the role of a histidine residue with the lowest solvent accessibility among other histidine residues at the end of a short connecting structure ((189)AELH(192)) of the catalytic domain of the exo-inulinase through creation of H192A mutant. Site-directed mutagenesis method was applied to create the mutant enzyme. Molecular dynamics (MD) simulations, spectroscopic, calorimetric and kinetics analysis were used to study the structural and functional consequences of His192 substitution. Accordingly, the thermo-stabilities and catalytic performance were decreased upon H192A mutation...
February 3, 2017: International Journal of Biological Macromolecules
Chi-Ming Pu, Chen-Wei Liu, Chan-Jung Liang, Yu-Hsiu Yen, Shun-Hua Chen, Ya-Fen Jiang-Shieh, Chung-Liang Chien, Ya-Chun Chen, Yuh-Lien Chen
Flap necrosis is the most frequent postoperative complication encountered in reconstructive surgery. We elucidated whether adipose-derived stem cells (ADSCs) and their derivatives might induce neovascularization and protect skin flaps during ischemia/reperfusion (I/R) injury. Flaps were subjected to 3 h of ischemia by ligating long thoracic vessels and then to blood reperfusion. Q-tracker-labeled ADSCs, conditioned media (ADSC-CM), or exosomes (ADSC-Exo) were injected into the flaps. These treatments led to significantly increase flap survival and capillary density compared to I/R on postoperative day 5...
February 2, 2017: Journal of Investigative Dermatology
Răzvan V Chereji, Josefina Ocampo, David J Clark
Micrococcal nuclease (MNase) is commonly used to map nucleosomes genome-wide, but nucleosome maps are affected by the degree of digestion. It has been proposed that many yeast promoters are not nucleosome-free but instead occupied by easily digested, unstable, "fragile" nucleosomes. We analyzed the histone content of all MNase-sensitive complexes by MNase-ChIP-seq and sonication-ChIP-seq. We find that yeast promoters are predominantly bound by non-histone protein complexes, with little evidence for fragile nucleosomes...
February 2, 2017: Molecular Cell
Haixiang Yu, Xiaowen Xu, Pingping Liang, Kang Yong Loh, Bhargav Guntupalli, Daniel Roncancio, Yi Xiao
DNA-modified particles are used extensively for applications in sensing, material science, and molecular biology. The performance of such DNA-modified particles is greatly dependent on the degree of surface coverage, but existing methods for quantitation can only be employed for certain particle compositions and/or conjugation chemistries. We have developed a simple and broadly applicable exonuclease III (Exo III) digestion assay based on the cleavage of phosphodiester bonds-a universal feature of DNA-modified particles-to accurately quantify DNA probe surface coverage on diverse, commonly used particles of different compositions, conjugation chemistries, and sizes...
February 15, 2017: Bioconjugate Chemistry
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