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https://www.readbyqxmd.com/read/28258564/the-evolutionary-aspects-of-aquaporin-family
#1
Kenichi Ishibashi, Yoshiyuki Morishita, Yasuko Tanaka
Aquaporins (AQPs ) are a family of transmembrane proteins present in almost all species including virus. They are grossly divided into three subfamilies based on the sequence around a highly conserved pore-forming NPA motif: (1) classical water -selective AQP (CAQP), (2) glycerol -permeable aquaglyceroporin (AQGP) and (3) AQP super-gene channel, superaquaporin (SAQP). AQP is composed of two tandem repeats of conserved three transmembrane domains and a NPA motif. AQP ancestors probably started in prokaryotes by the duplication of half AQP genes to be diversified into CAQPs or AQGPs by evolving a subfamily-specific carboxyl-terminal NPA motif...
2017: Advances in Experimental Medicine and Biology
https://www.readbyqxmd.com/read/28193058/development-of-a-biocompatible-in-tube-solid-phase-microextraction-device-a-sensitive-approach-for-direct-analysis-of-single-drops-of-complex-matrixes
#2
Hamed Piri-Moghadam, Sofia Lendor, Janusz Pawliszyn
The aim of the current study is to develop a sensitive solid-phase microextraction (SPME) device for direct and rapid analysis of untreated complex matrixes (i.e., single drop of the samples, V ≤ 2 μL). A thin layer of a biocompatible nanostructured polypyrrole (PPy) was electrochemically deposited inside a medical grade spinal needle, minimizing the matrix effect. Microsampling was facilitated by loading the sample inside the in-tube SPME device (withdraw of sample via plunger), where extraction was performed under static conditions...
December 20, 2016: Analytical Chemistry
https://www.readbyqxmd.com/read/28185621/an-alternative-perspective-of-hollow-fiber-mediated-extraction-bundled-hollow-fiber-array-liquid-phase-microextraction-with-sonication-assisted-desorption-and-liquid-chromatography-tandem-mass-spectrometry-for-determination-of-estrogens-in-aqueous-matrices
#3
Shalene Xue Lin Goh, Hian Kee Lee
A bundled hollow fiber array (BHF)-liquid-phase microextraction (LPME) approach has been developed for the ultra-high performance liquid chromatography tandem mass spectrometric determination of estrone, 17β-estradiol, estriol, and 17α-ethinylestradiol. The BHF was dipped in n-octanol to impregnate only the wall pores of the hollow fibers without deliberate loading of extractant solvent in the lumens, before placing it in the sample for extraction. Parameters influencing extraction efficiency, such as number of bundled hollow fibers, type of extraction and desorption solvent, agitation mode, extraction temperature and duration, and the salting out effect were examined...
March 10, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28097273/integration-of-multiple-active-sites-on-large-pore-mesoporous-silica-for-enantioselective-tandem-reactions
#4
Xuelin Xia, Jingjing Meng, Hanxin Wu, Tanyu Cheng, Guohua Liu
Facile construction of a multifunctional heterogeneous catalyst through the assembly of Au/carbene and chiral ruthenium/diamine dual complexes in large-pore mesoporous silica was developed. This enables an efficient one-pot hydration-asymmetric transfer hydrogenation enantioselective tandem reaction of haloalkynes, affording chiral halohydrins with up to 99% enantioselectivity. Combined multifunctionalities, such as substrate-promoted silanol-functionality, BF4(-) anion-bonding gold/carbene and covalent-bonding chiral ruthenium/diamine active centers, contributed cooperatively to the catalytic performance...
January 18, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/28077236/high-resolution-ultrahigh-pressure-long-column-reversed-phase-liquid-chromatography-for-top-down-proteomics
#5
Yufeng Shen, Nikola Tolić, Paul D Piehowski, Anil K Shukla, Sangtae Kim, Rui Zhao, Yi Qu, Errol Robinson, Richard D Smith, Ljiljana Paša-Tolić
Separation of proteoforms for global intact protein analysis (i.e. top-down proteomics) has lagged well behind what is achievable for peptides in traditional bottom-up proteomic approach and is becoming a true bottle neck for top-down proteomics. Herein, we report use of long (≥1M) columns containing short alkyl (C1-C4) bonded phases to achieve high-resolution RPLC for separation of proteoforms. At a specific operation pressure limit (i.e., 96.5MPa or 14Kpsi used in this work), column length was found to be the most important factor for achieving maximal resolution separation of proteins when 1...
January 5, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28058697/macro-scale-model-study-of-a-tunable-drug-dispensation-mechanism-for-controlled-drug-delivery-in-potential-wound-healing-applications
#6
Mariam Mir, Umar Ansari, Murtaza Najabat Ali
BACKGROUND: Auxetic materials tend to exhibit stretching in the direction of the applied load as well as in the perpendicular direction. This may be an inherent property of the material, or it might be a particular structural characteristic that confers it with auxetic properties. In this study, the auxetic properties of a rotating squares auxetic design were utilized in tandem with a stretching mechanism to manufacture a device that offers the advantages of adjustable pore size and hence tunable drug delivery characteristics...
October 10, 2016: Journal of Applied Biomaterials & Functional Materials
https://www.readbyqxmd.com/read/27987026/phosphoproteomics-of-colon-cancer-metastasis-comparative-mass-spectrometric-analysis-of-the-isogenic-primary-and-metastatic-cell-lines-sw480-and-sw620
#7
Alissa J Schunter, Xiaoshan Yue, Amanda B Hummon
The contributions of phosphorylation-mediated signaling networks to colon cancer metastasis are poorly defined. To interrogate constitutive signaling alterations in cancer progression, the global phosphoproteomes of patient-matched SW480 (primary colon tumor origin) and SW620 (lymph node metastasis) cell lines were compared with TiO2 and immobilized metal affinity chromatography phosphopeptide enrichment followed by liquid chromatography-tandem mass spectrometry. Network analysis of the significantly altered phosphosites revealed differential regulation in cellular adhesion, mitosis, and messenger RNA translational machinery...
March 2017: Analytical and Bioanalytical Chemistry
https://www.readbyqxmd.com/read/27610039/damgo-modulates-two-pore-domain-k-channels-in-the-substantia-gelatinosa-neurons-of-rat-spinal-cord
#8
Pyung Sun Cho, Han Kyu Lee, Sang Hoon Lee, Jay Zoon Im, Sung Jun Jung
The analgesic mechanism of opioids is known to decrease the excitability of substantia gelatinosa (SG) neurons receiving the synaptic inputs from primary nociceptive afferent fiber by increasing inwardly rectifying K(+) current. In this study, we examined whether a µ-opioid agonist, [D-Ala2,N-Me-Phe4, Gly5-ol]-enkephalin (DAMGO), affects the two-pore domain K(+) channel (K2P) current in rat SG neurons using a slice whole-cell patch clamp technique. Also we confirmed which subtypes of K2P channels were associated with DAMGO-induced currents, measuring the expression of K2P channel in whole spinal cord and SG region...
September 2016: Korean Journal of Physiology & Pharmacology
https://www.readbyqxmd.com/read/27566292/dysregulation-of-a-potassium-channel-thik-1-targeted-by-caspase-8-accelerates-cell-shrinkage
#9
Kazuhiro Sakamaki, Takahiro M Ishii, Toshiya Sakata, Kiwamu Takemoto, Chiyo Takagi, Ayako Takeuchi, Ryo Morishita, Hirotaka Takahashi, Akira Nozawa, Hajime Shinoda, Kumiko Chiba, Haruyo Sugimoto, Akiko Saito, Shuhei Tamate, Yutaka Satou, Sang-Kee Jung, Satoshi Matsuoka, Koji Koyamada, Tatsuya Sawasaki, Takeharu Nagai, Naoto Ueno
Activation of caspases is crucial for the execution of apoptosis. Although the caspase cascade associated with activation of the initiator caspase-8 (CASP8) has been investigated in molecular and biochemical detail, the physiological role of CASP8 is not fully understood. Here, we identified a two-pore domain potassium channel, tandem-pore domain halothane-inhibited K(+) channel 1 (THIK-1), as a novel CASP8 substrate. The intracellular region of THIK-1 was cleaved by CASP8 in apoptotic cells. Overexpression of THIK-1, but not its mutant lacking the CASP8-target sequence in the intracellular portion, accelerated cell shrinkage in response to apoptotic stimuli...
November 2016: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/27558839/hyaluronan-synthase-control-of-synthesis-rate-and-hyaluronan-product-size-are-independent-functions-differentially-affected-by-mutations-in-a-conserved-tandem-b-x7-b-motif
#10
Bruce A Baggenstoss, Edward N Harris, Jennifer L Washburn, Andria P Medina, Long Nguyen, Paul H Weigel
Hyaluronan synthases (HAS) normally make large (>MDa) hyaluronan (HA) products. Smaller HA fragments (e.g. 100-400 kDa) produced in vivo are associated with inflammation and cell signaling by HA receptors that bind small, but not large, HA. Although HA fragments can arise from breakdown by hyaluronidases, HAS might also be regulated directly to synthesize small HA. Here we examined the Streptococcus equisimilis HAS (SeHAS) C-terminus, which contains a tandem B-X7-B motif (K(398)-X7-R(406)-X7-K(414)), by testing the effects of 27 site-specific scanning mutations and 7 C-terminal truncations on HA synthesis activity and weight-average mass...
January 2017: Glycobiology
https://www.readbyqxmd.com/read/27412322/application-of-a-hybrid-ordered-mesoporous-silica-as-sorbent-for-solid-phase-multi-residue-extraction-of-veterinary-drugs-in-meat-by-ultra-high-performance-liquid-chromatography-coupled-to-ion-trap-tandem-mass-spectrometry
#11
Natalia Casado, Sonia Morante-Zarcero, Damián Pérez-Quintanilla, Isabel Sierra
A quick, sensitive and selective analytical reversed-phase multi-residue method using ultra-high performance liquid chromatography coupled to an ion-trap mass spectrometry detector (UHPLC-IT-MS/MS) operating in both positive and negative ion mode was developed for the simultaneous determination of 23 veterinary drug residues (β-blockers, β-agonists and Non-Steroidal Anti-inflammatory Drugs (NSAIDs)) in meat samples. The sample treatment involved a liquid-solid extraction followed by a solid-phase extraction (SPE) procedure...
August 12, 2016: Journal of Chromatography. A
https://www.readbyqxmd.com/read/27411857/phylogenetic-evidence-for-a-fusion-of-archaeal-and-bacterial-semisweets-to-form-eukaryotic-sweets-and-identification-of-sweet-hexose-transporters-in-the-amphibian-chytrid-pathogen-batrachochytrium-dendrobatidis
#12
Yi-Bing Hu, Davide Sosso, Xiao-Qing Qu, Li-Qing Chen, Lai Ma, Diane Chermak, De-Chun Zhang, Wolf B Frommer
SWEETs represent a new class of sugar transporters first described in plants and animals/humans and later in prokaryotes. Plant SWEETs play key roles in phloem loading, seed filling, and nectar secretion, whereas the role of archaeal, bacterial, and animal transporters remains elusive. Structural analyses show that eukaryotic SWEETs are composed of 2 triple-helix bundles (THBs) fused via an inversion linker helix, whereas prokaryotic SemiSWEETs contain only a single THB and require homodimerization to form transport pores...
July 13, 2016: FASEB Journal: Official Publication of the Federation of American Societies for Experimental Biology
https://www.readbyqxmd.com/read/27346625/seven-post-synthetic-covalent-reactions-in-tandem-leading-to-enzyme-like-complexity-within-metal-organic-framework-crystals
#13
Alejandro M Fracaroli, Peter Siman, David A Nagib, Mitsuharu Suzuki, Hiroyasu Furukawa, F Dean Toste, Omar M Yaghi
The design of enzyme-like complexity within metal-organic frameworks (MOFs) requires multiple reactions to be performed on a MOF crystal without losing access to its interior. Here, we show that seven post-synthetic reactions can be successfully achieved within the pores of a multivariate MOF, MTV-IRMOF-74-III, to covalently incorporate tripeptides that resemble the active sites of enzymes in their spatial arrangement and compositional heterogeneity. These reactions build up H2N-Pro-Gly-Ala-CONHL and H2N-Cys-His-Asp-CONHL (where L = organic struts) amino acid sequences by covalently attaching them to the organic struts in the MOFs, without losing porosity or crystallinity...
July 13, 2016: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/27307105/the-rickettsia-type-iv-secretion-system-unrealized-complexity-mired-by-gene-family-expansion
#14
Joseph J Gillespie, Isabelle Q H Phan, Timothy P Driscoll, Mark L Guillotte, Stephanie S Lehman, Kristen E Rennoll-Bankert, Sandhya Subramanian, Magda Beier-Sexton, Peter J Myler, M Sayeedur Rahman, Abdu F Azad
Many prokaryotes utilize type IV secretion systems (T4SSs) to translocate substrates (e.g. nucleoprotein, DNA, protein) across the cell envelope, and/or to elaborate surface structures (i.e. pili or adhesins). Among eight distinct T4SS classes, P-T4SSs are typified by the Agrobacterium tumefaciens vir T4SS, which is comprised of 12 scaffold components (VirB1-VirB11, VirD4). While most P-T4SSs include all 12 Vir proteins, some differ from the vir archetype by either containing additional scaffold components not analogous to Vir proteins or lacking one or more of the Vir proteins...
August 2016: Pathogens and Disease
https://www.readbyqxmd.com/read/27303791/impact-of-the-crystallization-condition-on-importin-%C3%AE-conformation
#15
Marcel J Tauchert, Clément Hémonnot, Piotr Neumann, Sarah Köster, Ralf Ficner, Achim Dickmanns
In eukaryotic cells, the exchange of macromolecules between the nucleus and cytoplasm is highly selective and requires specialized soluble transport factors. Many of them belong to the importin-β superfamily, the members of which share an overall superhelical structure owing to the tandem arrangement of a specific motif, the HEAT repeat. This structural organization leads to great intrinsic flexibility, which in turn is a prerequisite for the interaction with a variety of proteins and for its transport function...
June 2016: Acta Crystallographica. Section D, Structural Biology
https://www.readbyqxmd.com/read/27268784/gating-regulation-and-structure-in-k2p-k-channels-in-varietate-concordia
#16
María Isabel Niemeyer, L Pablo Cid, Wendy González, Francisco V Sepúlveda
K2P K(+) channels with two pore domains in tandem associate as dimers to produce so-called background conductances that are regulated by a variety of stimuli. Whereas gating in K2P channels has been poorly understood, recent developments have provided important clues regarding the gating mechanism for this family of proteins. Two modes of gating present in other K(+) channels have been considered. The first is the so-called activation gating that occurs by bundle crossing and the splaying apart of pore-lining helices commanding ion passage...
September 2016: Molecular Pharmacology
https://www.readbyqxmd.com/read/27234848/polydopamine-reinforced-magnetization-of-zeolitic-imidazolate-framework-zif-7-for-magnetic-solid-phase-extraction-of-polycyclic-aromatic-hydrocarbons-from-the-air-water-environment
#17
Suling Zhang, Weixuan Yao, Jianbo Ying, Hongting Zhao
Zeolitic imidazolate frameworks (ZIFs) consist of metal nodes connected to imidazolate linkers, having both the properties of metal-organic frameworks (MOFs) and inorganic zeolites, such as controllable pore sizes, high porosity and surface areas, as well as exceptional thermal and chemical stability, thereby making them a class of attractive materials for diverse analytical applications. In this study, we reported a facile magnetization process of ZIF-7 (zinc benzimidazolate) for simultaneous magnetic extraction of polycyclic aromatic hydrocarbons (PAHs) by simply mixing ZIF-7 and polydopamine (PDA)-coated Fe3O4 nanoparticles (PDA@Fe3O4) in solutions...
June 24, 2016: Journal of Chromatography. A
https://www.readbyqxmd.com/read/27129242/formation-of-functional-heterodimers-by-trek-1-and-trek-2-two-pore-domain-potassium-channel-subunits
#18
Miklós Lengyel, Gábor Czirják, Péter Enyedi
Two-pore domain (K2P) potassium channels are the major molecular correlates of the background (leak) K(+) current in a wide variety of cell types. They generally play a key role in setting the resting membrane potential and regulate the response of excitable cells to various stimuli. K2P channels usually function as homodimers, and only a few examples of heteromerization have been previously reported. Expression of the TREK (TWIK-related K(+) channel) subfamily members of K2P channels often overlaps in neurons and in other excitable cells...
June 24, 2016: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/27100905/influence-of-acid-chain-length-on-the-properties-of-tio2-prepared-by-sol-gel-method-and-lc-ms-studies-of-methylene-blue-photodegradation
#19
Pratibha V Bakre, Prajesh S Volvoikar, Amit A Vernekar, S G Tilve
Nano-sized titanium dioxide photocatalysts were synthesized by hybrid hydrolytic nonhydrolytic sol-gel method using aliphatic organic acid templates to study the effect of chain length on their properties. X-ray diffraction pattern indicated crystalline anatase phase. The Barrett-Joyner-Halenda surface area measurement gave surface area ranging from 98.4 to 205.5m(2)/g and was found to be dependent on the chain length of the aliphatic acid. The longer chain acids rendered the material with high surface area...
July 15, 2016: Journal of Colloid and Interface Science
https://www.readbyqxmd.com/read/27077920/quantification-of-hydrogen-concentrations-in-surface-and-interface-layers-and-bulk-materials-through-depth-profiling-with-nuclear-reaction-analysis
#20
Markus Wilde, Satoshi Ohno, Shohei Ogura, Katsuyuki Fukutani, Hiroyuki Matsuzaki
Nuclear reaction analysis (NRA) via the resonant (1)H((15)N,αγ)(12)C reaction is a highly effective method of depth profiling that quantitatively and non-destructively reveals the hydrogen density distribution at surfaces, at interfaces, and in the volume of solid materials with high depth resolution. The technique applies a (15)N ion beam of 6.385 MeV provided by an electrostatic accelerator and specifically detects the (1)H isotope in depths up to about 2 μm from the target surface. Surface H coverages are measured with a sensitivity in the order of ~10(13) cm(-2) (~1% of a typical atomic monolayer density) and H volume concentrations with a detection limit of ~10(18) cm(-3) (~100 at...
March 29, 2016: Journal of Visualized Experiments: JoVE
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