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https://www.readbyqxmd.com/read/28746182/plumbagin-loaded-aptamer-targeted-poly-d-l-lactic-co-glycolic-acid-b-polyethylene-glycol-nanoparticles-for-prostate-cancer-therapy
#1
Minjie Pan, Weifeng Li, Jun Yang, Zhiqin Li, Jun Zhao, Yajun Xiao, Yifei Xing, Xiaoping Zhang, Wen Ju
Plumbagin inhibits the growth, metastasis, and invasion of prostate cancer (PCa). However, its lower bioavailability limits biopharmaceutical properties due to insolubility in water. Prostate-specific membrane antigen (PSMA) aptamer-targeted nanoparticles (NPs) significantly enhanced cytotoxicity in prostate epithelial cells. This study aimed to investigate the effects of plumbagin-loaded prostate-specific membrane antigen (PSMA) aptamer-targeted poly D,L-lactic-co-glycolic acid-b-polyethylene glycol (PLGA-PEG) nanoparticles (NPs) on prostate cancer (PCa) in vitro...
July 2017: Medicine (Baltimore)
https://www.readbyqxmd.com/read/28737891/dynamic-chemistry-based-sensing-a-molecular-system-for-detection-of-saccharide-formaldehyde-and-silver-ion
#2
Xingmao Chang, Zhaolong Wang, Yanyu Qi, Rui Kang, Xinwen Cui, Congdi Shang, Kaiqiang Liu, Yu Fang
Development of artificial complex molecular systems is of great importance in understanding complexity in natural processes and for achieving new functionalities. One of the strategies is to create them via optimized utilization of noncovalent interactions and dynamic covalent bonds. We report here on a new complex molecular system, which was constructed by integrating the multiple interactions containing dynamic covalent interaction between 1,2-diol and boronic acid, coordination interaction between silver ion and pyridyl, and an easy accessible reaction between secondary amine and formaldehyde...
July 24, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28735093/stable-isotope-labeling-by-fatty-acids-in-cell-culture-silfac-coupled-with-isotope-pattern-dependent-mass-spectrometry-for-global-screening-of-lipid-hydroperoxide-mediated-protein-modifications
#3
Ryo Takahashi, Shuhei Fujioka, Tomoyuki Oe, Seon Hwa Lee
Lipid hydroperoxide-mediated modifications of proteins are receiving increasing attention because of their possible involvement in various degenerative diseases. These biological effects are attributed to the ability of lipid peroxidation-derived aldehydes to react with the nucleophilic sites of proteins. Here we describe a methodology involving metabolic labeling coupled with mass spectrometry-based proteomic analysis that enables global screening of lipid hydroperoxide-mediated protein modifications in a cell system...
July 19, 2017: Journal of Proteomics
https://www.readbyqxmd.com/read/28733410/radioactive-labeling-and-fractionation-of-fission-yeast-walls
#4
Pilar Pérez, Juan C Ribas
Fungal cells contain an essential structure external to the cell, made of polysaccharides and proteins, termed the cell wall. Polysaccharides represent ∼96% of the cell wall on a dry-weight basis. They are complex insoluble polymers connected to each other by covalent linkages and hydrogen bonds with specific localizations in the cell wall and septum. Fission yeast contains three β-glucans (a major branched β(1,3)-glucan, a minor linear β(1,3)-glucan, and a minor branched β(1,6)-glucan), two α-glucans (a major α(1,3)-glucan and a minor α(1,4)-glucan), and a minor amount of galactomannan-linked glycoproteins...
July 21, 2017: Cold Spring Harbor Protocols
https://www.readbyqxmd.com/read/28726964/a-%C3%AE-galactosidase-probe-for-the-detection-of-cellular-senescence-by-mass-cytometry
#5
M A Lumba, L M Willis, S Santra, R Rana, L Schito, S Rey, B G Wouters, M Nitz
Mass cytometry (MC) is a powerful method that combines the cellular resolution of flow cytometry with the isotopic resolution of inductively coupled plasma mass spectrometry (ICP-MS). This combination theoretically allows for the simultaneous quantification of >80 different parameters at the single cell level, in turn allowing for the deep profiling of heterogeneous cell populations. The majority of available reagents for MC are antibodies labeled with heavy metal isotopes, allowing for the quantification of static biomarkers...
July 20, 2017: Organic & Biomolecular Chemistry
https://www.readbyqxmd.com/read/28726379/topological-dissection-of-the-membrane-transport-protein-mhp1-derived-from-cysteine-accessibility-and-mass-spectrometry
#6
Antonio Nickolas Calabrese, Scott M Jackson, Lynsey N Jones, Oliver Beckstein, Florian Heinkel, Joerg Gsponer, David Sharples, Marta Sans, Maria Kokkinidou, Arwen R Pearson, Sheena E Radford, Alison E Ashcroft, Peter J F Henderson
Cys accessibility and quantitative intact mass spectrometry (MS) analyses have been devised to study the topological transitions of Mhp1, the membrane protein for sodium-linked transport of hydantoins from Microbacterium liquefaciens. Mhp1 has been crystallised in three forms (outward-facing open, outward-facing occluded with substrate bound, and inward-facing open). We show that one natural cysteine residue, Cys327, out of three, has an enhanced solvent accessibility in the inward-facing (relative to the outward-facing) form...
July 20, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28723134/isoelectric-bovine-serum-albumin-robust-blocking-agent-for-enhanced-performance-in-optical-fiber-based-dna-sensing
#7
Ruoyu Wang, Xiaohong Zhou, Xiyu Zhu, Chao Yang, Lanhua Liu, Hanchang Shi
Surface blocking is a well-known process for reducing unwanted nonspecific adsorption in sensor fabrication, especially important in the emerging field where DNA/RNA applied. Bovine serum albumin (BSA) is one of the most popular blocking agents with an isoelectric point at pH 4.6. Although it is widely recognized that the adsorption of a blocking agent is strongly affected by its net charge and the maximum adsorption is often observed under its isoelectric form, BSA has long been perfunctorily used for blocking merely in neutral solution, showing poor blocking performances in the optical-fiber evanescent wave (OFEW) based sensing toward DNA target...
February 24, 2017: ACS Sensors
https://www.readbyqxmd.com/read/28723071/maleic-anhydride-labeling-based-approach-for-quantitative-proteomics-and-successive-derivatization-of-peptides
#8
Shanshan Tian, Shuzhen Zheng, Yanpu Han, Zhenchang Guo, Guijin Zhai, Xue Bai, Xi-Wen He, Enguo Fan, YuKui Zhang, Kai Zhang
Chemical derivatization is a simple approach for stable-isotope covalent labeling of proteins in quantitative proteomics. Herein we describe the development of a novel maleyl-labeling-based approach for protein quantification. Under optimized conditions, maleic anhydride can serve as a highly-efficient reagent to label the amino groups of tryptic peptides. Furthermore, 'click chemistry'was successfully applied to obtain the second modification of maleylated peptides via thiol-Michael addition reaction. Accurate quantification was further achieved via the first or/and second step stable-isotope labeling in this study...
July 19, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28720784/snap-tagged-chikungunya-virus-replicons-improve-visualisation-of-non-structural-protein-3-by-fluorescence-microscopy
#9
Roland Remenyi, Grace C Roberts, Carsten Zothner, Andres Merits, Mark Harris
Chikungunya virus (CHIKV), a mosquito-borne alphavirus, causes febrile disease, muscle and joint pain, which can become chronic in some individuals. The non-structural protein 3 (nsP3) plays essential roles during infection, but a complete understanding of its function is lacking. Here we used a microscopy-based approach to image CHIKV nsP3 inside human cells. The SNAP system consists of a self-labelling enzyme tag, which catalyses the covalent linking of exogenously supplemented synthetic ligands. Genetic insertion of this tag resulted in viable replicons and specific labelling while preserving the effect of nsP3 on stress granule responses and co-localisation with GTPase Activating Protein (SH3 domain) Binding Proteins (G3BPs)...
July 18, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28720752/a-quasi-direct-lc-ms-ms-based-targeted-proteomics-approach-for-mirna-quantification-via-a-covalently-immobilized-dna-peptide-probe
#10
Liang Liu, Qingqing Xu, Shuai Hao, Yun Chen
MicroRNAs (miRNAs) play a vital role in regulating gene expression and are associated with a variety of cancers, including breast cancer. Their distorted and unique expression is a potential marker in clinical diagnoses and prognoses. Thus, accurate determination of miRNA expression levels is a prerequisite for their applications. However, the assays currently available for miRNA detection typically require pre-enrichment, amplification and labeling steps, and most of the assays are only semi-quantitative. Therefore, we developed a quasi-direct liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based targeted proteomics approach to quantify target miRNA by innovatively converting the miRNA signal into the mass response of a reporter peptide via a covalently immobilized DNA-peptide probe...
July 18, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28718649/ensemble-and-single-particle-fluorescence-characterization-of-dye-labeled-cellulose-nanocrystals
#11
Tianyang Leng, Zygmunt J Jakubek, Mahyar Mazloumi, Alfred C W Leung, Linda J Johnston
Cellulose nanocrystals (CNCs) have been covalently labeled with both fluorescein and rhodamine and studied by a combination of UV-Vis absorption spectroscopy and ensemble and single molecule fluorescence spectroscopy. For all samples the fluorescence anisotropy and lifetimes were consistent with effects expected for covalently bound dye molecules. Low dye loading levels (~ 0.1 dye/particle) were estimated for the fluorescein-labeled CNC which coupled with the strong pH dependence make this a less suitable fluorophore for most applications...
July 18, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28718624/covalent-enzyme-inhibition-through-fluorosulfate-modification-of-a-non-catalytic-serine-residue
#12
Olugbeminiyi O Fadeyi, Lise R Hoth, Chulho Choi, Xidong Feng, Ariamala Gopalsamy, Erik C Hett, Robert E Kyne, Ralph P Robinson, Lyn H Jones
Irreversible enzyme inhibitors often utilize the reaction of a protein cysteine residue with an appropriately positioned electrophile (an acrylamide for example) in the ligand template. Cysteine residues are not always available for site-specific protein labeling and therefore new approaches are needed to expand the toolkit of appropriate electrophiles that target alternative amino acids. We have previously described the rational targeting of tyrosine residues in the active site of a protein (the mRNA decapping scavenger enzyme, DcpS) using inhibitors armed with sulfonyl fluoride electrophiles that additionally enabled the subsequent development of clickable probe technology to measure drug-target occupancy in live cells...
July 18, 2017: ACS Chemical Biology
https://www.readbyqxmd.com/read/28717581/detection-of-echinococcus-granulosus-antigen-by-a-quantum-dot-porous-silicon-optical-biosensor
#13
Yanyu Li, Zhenhong Jia, Guodong Lv, Hao Wen, Peng Li, Hongyan Zhang, Jiajia Wang
Highly sensitive labeled detection of Echinococcus granulosus using colloidal quantum dots (QDs) based on a porous silicon Bragg mirror sensor are demonstrated. Rabbit anti-p38 labeled CdSe/ZnS QDs was infiltrated in porous silicon pores immobilized Egp38 antigen. QD-antibodies are specifically bound to antigens linked covalently to the pore walls of PSi after the immune reaction. By the design of the transfer matrix method and the preparation of the electrochemical etching method, the fluorescence peak wavelength of the quantum dots is located in the forbidden band of the Bragg mirror...
July 1, 2017: Biomedical Optics Express
https://www.readbyqxmd.com/read/28710004/development-of-pegylated-carboxylic-acid-modified-polyamidoamine-dendrimers-as-bone-targeting-carriers-for-the-treatment-of-bone-diseases
#14
Shugo Yamashita, Hidemasa Katsumi, Nozomi Hibino, Yugo Isobe, Yumiko Yagi, Kosuke Kusamori, Toshiyasu Sakane, Akira Yamamoto
In this study, we aimed to develop a polyethylene glycol (PEG)-conjugated third generation polyamidoamine (PAMAM) dendrimer with multiple carboxylic acids as a bone-targeting carrier for the treatment of bone diseases. We conjugated PAMAM backbones to various carboxylic acids [aspartic acid (Asp), glutamic acid (Glu), succinic acid (Suc), or aconitic acid (Aco)] to obtain four different types of carboxylic acid-modified PAMAMs. PEG was covalently bound to carboxylic acid-modified PAMAMs to obtain PEGylated carboxylic acid-modified PAMAMs...
July 11, 2017: Journal of Controlled Release: Official Journal of the Controlled Release Society
https://www.readbyqxmd.com/read/28704926/a-label-free-and-ultrasensitive-immunosensor-for-detection-of-human-chorionic-gonadotrophin-based-on-graphene-fets
#15
Kamrul Islam, Ahmed Suhail, Genhua Pan
We report on a label-free immunosensor based on graphene field effect transistors (G-FETs) for the ultrasensitive detection of Human Chorionic Gonadotrophin (hCG), as an indicator of pregnancy and related disorders, such as actopic pregnancy, choriocarcinoma and orchic teratoma. Pyrene based bioactive ester was non-covalently anchored onto the graphene channel in order to retain the sp² lattice. The G-FET transfer characteristics showed repeatable and reliable responses in all surface modifying steps using a direct current (DC) readout system...
July 12, 2017: Biosensors
https://www.readbyqxmd.com/read/28700926/the-energetics-of-chromophore-binding-in-the-visual-photoreceptor-rhodopsin
#16
He Tian, Thomas P Sakmar, Thomas Huber
The visual photoreceptor rhodopsin is a prototypical G-protein-coupled receptor (GPCR) that stabilizes its inverse agonist ligand, 11-cis-retinal (11CR), by a covalent, protonated Schiff base linkage. In the visual dark adaptation, the fundamental molecular event after photobleaching of rhodopsin is the recombination reaction between its apoprotein opsin and 11CR. Here we present a detailed analysis of the kinetics and thermodynamics of this reaction, also known as the "regeneration reaction". We compared the regeneration of purified rhodopsin reconstituted into phospholipid/detergent bicelles with rhodopsin reconstituted into detergent micelles...
July 11, 2017: Biophysical Journal
https://www.readbyqxmd.com/read/28700219/versatile-site-selective-protein-reaction-guided-by-ww-domain-peptide-motif-interaction
#17
Miao Liu, Zeyang Ji, Mingjie Zhang, Jiang Xia
A short, flexible and unstructured peptide tag that has versatile and facile use in protein labeling applications is highly desirable. Here, we report an 11-residue peptide tag with an internal cysteine (a W-tag, derived from a Comm PY peptide motif that is known to bind with Nedd4 WW3* domain) that can be installed at different regions of the target protein without compromising its covalent reactivity with the reactive label (a 35-residue synthetic Nedd4 WW3* domain derivative). This versatility is explained by the unique structural features of the reaction...
July 12, 2017: Bioconjugate Chemistry
https://www.readbyqxmd.com/read/28684316/regulation-of-calcium-release-from-the-endoplasmic-reticulum-by-the-serine-hydrolase-abhd2
#18
Bogeon Yun, HeeJung Lee, Roger Powell, Nichole Reisdorph, Heather Ewing, Michael H Gelb, Ku-Lung Hsu, Benjamin F Cravatt, Christina C Leslie
The serine hydrolase inhibitors pyrrophenone and KT195 inhibit cell death induced by A23187 and H2O2 by blocking the release of calcium from the endoplasmic reticulum and mitochondrial calcium uptake. The effect of pyrrophenone and KT195 on these processes is not due to inhibition of their known targets, cytosolic phospholipase A2 and α/β-hydrolase domain-containing (ABHD) 6, respectively, but represent off-target effects. To identify targets of KT195, fibroblasts were treated with KT195-alkyne to covalently label protein targets followed by click chemistry with biotin azide, enrichment on streptavidin beads and tryptic peptide analysis by mass spectrometry...
July 3, 2017: Biochemical and Biophysical Research Communications
https://www.readbyqxmd.com/read/28682613/synthesis-of-a-3-amino-2-3-dihydropyrid-4-one-and-related-heterocyclic-analogs-as-mechanism-based-inhibitors-of-bioa-a-pyridoxal-phosphate-plp-dependent-enzyme
#19
Carter G Eiden, Courtney C Aldrich
Amiclenomycin (ACM) is a chemically unstable antibiotic with selective activity against Mycobacterium tuberculosis (Mtb) due to mechanism-based inhibition of BioA, a pyridoxal 5'-phosphate (PLP) dependent aminotransferase that catalyzes the second step of biotin biosynthesis. The first-generation ACM analogue dihydro-2-pyridone 1 is semi-stable and maintains a similar bioactivation mechanism concluding with covalent labeling of the PLP cofactor. To improve on 1, we report the synthesis of dihydro-4-pyranone 2, dihydro-4-pyridone 3 and dihydro-4-thiopyranone 13...
July 6, 2017: Journal of Organic Chemistry
https://www.readbyqxmd.com/read/28678845/polymerase-free-measurement-of-microrna-122-with-single-base-specificity-using-single-molecule-arrays-detection-of-drug-induced-liver-injury
#20
David M Rissin, Barbara López-Longarela, Salvatore Pernagallo, Hugh Ilyine, A D Bastiaan Vliegenthart, James W Dear, Juan J Díaz-Mochón, David C Duffy
We have developed a single probe method for detecting microRNA from human serum using single molecule arrays, with sequence specificity down to a single base, and without the use of amplification by polymerases. An abasic peptide nucleic acid (PNA) probe-containing a reactive amine instead of a nucleotide at a specific position in the sequence-for detecting a microRNA was conjugated to superparamagnetic beads. These beads were incubated with a sample containing microRNA, a biotinylated reactive nucleobase-containing an aldehyde group-that was complementary to the missing base in the probe sequence, and a reducing agent...
2017: PloS One
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