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https://www.readbyqxmd.com/read/28623702/adsorption-of-ionic-surfactants-at-microscopic-air-water-interfaces-using-the-micropipette-interfacial-area-expansion-method-measurement-of-the-diffusion-coefficient-and-renormalization-of-the-mean-ionic-activity-for-sds
#1
Koji Kinoshita, Elisa Parra, David Needham
The dynamic adsorption of ionic surfactants at air-water interfaces have been less-well studied than that of the simpler non-ionics since experimental limitations on dynamic surface tension (DST) measurements create inconsistencies in their kinetic analysis. Using our newly designed "Micropipette interfacial area-expansion method", we have measured and evaluated both equilibrium and dynamic adsorption of a well-known anionic surfactant, sodium dodecyl sulphate (SDS), in the absence or presence of 100mM NaCl...
May 25, 2017: Journal of Colloid and Interface Science
https://www.readbyqxmd.com/read/28605904/kalata-b1-and-kalata-b2-have-a-surfactant-like-activity-in-phosphatidylethanolomine-containing-lipid-membranes
#2
Charles G Cranfield, Sónia Troeira Henriques, Boris Martinac, Paul Duckworth, David J Craik, Bruce Cornell
Cyclotides are cyclic disulfide-rich peptides that are chemically and thermally stable and possess pharmaceutical and insecticidal properties. The activities reported for cyclotides correlate with their ability to target phosphatidylethanolamine (PE)-phospholipids and disrupt cell membranes. However, the mechanism by which this disruption occurs remains unclear. In the current study we examine the effect of the prototypic cyclotides, kalata B1 (kB1) and kalata B2 (kB2), on tethered lipid bilayer membranes (tBLMs) using swept frequency electrical impedance spectroscopy...
June 21, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28594046/balancing-the-intermolecular-forces-in-peptide-amphiphiles-for-controlling-self-assembly-transitions
#3
C J Buettner, A J Wallace, S Ok, A A Manos, M J Nicholl, A Ghosh, M F Tweedle, J E Goldberger
While the influence of alkyl chain length and headgroup size on self-assembly behaviour has been well-established for simple surfactants, the rational control over the pH- and concentration-dependent self-assembly behaviour in stimuli responsive peptides remains an elusive goal. Here, we show that different amphiphilic peptides can have similar self-assembly phase diagrams, providing the relative strengths of the attractive and repulsive forces are balanced. Using palmitoyl-YYAAEEEEK(DO3A:Gd)-NH2 and palmitoyl-YAAEEEEK(DO3A:Gd)-NH2 as controls, we show that reducing hydrophobic attractive forces through fewer methylene groups in the alkyl chain will lead to a similar self-assembly phase diagram as increasing the electrostatic repulsive forces via the addition of a glutamic acid residue...
June 21, 2017: Organic & Biomolecular Chemistry
https://www.readbyqxmd.com/read/28570277/epithelial-gpr116-regulates-pulmonary-alveolar-homeostasis-via-gq-11-signaling
#4
Kari Brown, Alyssa Filuta, Marie-Gabrielle Ludwig, Klaus Seuwen, Julian Jaros, Solange Vidal, Kavisha Arora, Anjaparavanda P Naren, Kathirvel Kandasamy, Kaushik Parthasarathi, Stefan Offermanns, Robert J Mason, William E Miller, Jeffrey A Whitsett, James P Bridges
Pulmonary function is dependent upon the precise regulation of alveolar surfactant. Alterations in pulmonary surfactant concentrations or function impair ventilation and cause tissue injury. Identification of the molecular pathways that sense and regulate endogenous alveolar surfactant concentrations, coupled with the ability to pharmacologically modulate them both positively and negatively, would be a major therapeutic advance for patients with acute and chronic lung diseases caused by disruption of surfactant homeostasis...
June 2, 2017: JCI Insight
https://www.readbyqxmd.com/read/28570040/self-assembly-of-mesoscopic-peptide-surfactant-fibrils-investigated-by-storm-super-resolution-fluorescence-microscopy
#5
Henry Cox, Pantelis Georgiades, Hai Xu, Thomas Andrew Waigh, Jian Ren Lu
Super-resolution fluorescence microscopy, specifically STOchastic Reconstruction Microscopy (STORM), and atomic force microscopy (AFM) were used to image the self-assembly processes of the peptide surfactant, I3K. The peptide surfactants self-assembled into giant helical fibrils with diameters between 5 and 10 nm with significant helical twisting. The resolution of the STORM images was 30 nm, calculated using the Fourier ring correlation method. STORM compares favorably with AFM for the calculation of contour lengths (~6 μm) and persistence lengths (10...
June 1, 2017: Biomacromolecules
https://www.readbyqxmd.com/read/28560564/an-electrospray-ionization-mass-spectrometry-study-on-the-in-vacuo-hetero-oligomers-formed-by-the-antimicrobial-peptides-surfactin-and-gramicidin-s
#6
Marina Rautenbach, N Maré Vlok, Hans A Eyéghé-Bickong, Marthinus J van der Merwe, Marietjie A Stander
It was previously observed that the lipopeptide surfactants in surfactin (Srf) have an antagonistic action towards the highly potent antimicrobial cyclodecapeptide, gramicidin S (GS). This study reports on some of the molecular aspects of the antagonism as investigated through complementary electrospray ionization mass spectrometry techniques. We were able to detect stable 1:1 and 2:1 hetero-oligomers in a mixture of surfactin and gramicidin S. The noncovalent interaction between GS and Srf, with the proposed equilibrium: GS~Srf↔GS+Srf correlated to apparent K d values of 6-9 μM in gas-phase and 1 μM in aqueous solution...
May 30, 2017: Journal of the American Society for Mass Spectrometry
https://www.readbyqxmd.com/read/28541037/phase-behavior-of-salt-free-polyelectrolyte-gel-surfactant-systems
#7
Martin Andersson, Per Hansson
Ionic surfactants tend to collapse the outer parts of polyelectrolyte gels, forming shells that can be used to encapsulate other species including protein and peptide drugs. In this paper, the aqueous phase behavior of covalently cross-linked polyacrylate networks containing sodium ions and dodecyltrimethylammonium ions as counterions is investigated by means of swelling isotherms, dye staining, small-angle X-ray scattering, and confocal Raman spectroscopy. The equilibrium state is approached by letting the networks absorb pure water...
June 8, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28540997/a-combination-of-short-and-simple-surfactant-protein-b-and-c-analogues-as-a-new-synthetic-surfactant-in-vitro-and-animal-experiments
#8
Yong Sung Choi, Sung Hoon Chung, Chong Woo Bae
PURPOSE: Pulmonary surfactants for preterm infants contain mostly animal-derived surfactant proteins (SPs), which are essential for lowering surface tension. We prepared artificial pulmonary surfactants using synthetic human SP analogs and performed in vitro and in vivo experiments. MATERIALS AND METHODS: We synthesized peptide analogues that resemble human SP-B (RMLPQLVCRLVLRCSMD) and SP-C (CPVHLKRLLLLLLLLLLLLLLLL). Dipalmitoylphosphatidylcholine (DPPC), phosphatidylglycerol (PG), and palmitic acid (PA) were added and mixed in lyophilized to render powdered surfactant...
July 2017: Yonsei Medical Journal
https://www.readbyqxmd.com/read/28534479/efficient-protein-production-inspired-by-how-spiders-make-silk
#9
Nina Kronqvist, Médoune Sarr, Anton Lindqvist, Kerstin Nordling, Martins Otikovs, Luca Venturi, Barbara Pioselli, Pasi Purhonen, Michael Landreh, Henrik Biverstål, Zigmantas Toleikis, Lisa Sjöberg, Carol V Robinson, Nicola Pelizzi, Hans Jörnvall, Hans Hebert, Kristaps Jaudzems, Tore Curstedt, Anna Rising, Jan Johansson
Membrane proteins are targets of most available pharmaceuticals, but they are difficult to produce recombinantly, like many other aggregation-prone proteins. Spiders can produce silk proteins at huge concentrations by sequestering their aggregation-prone regions in micellar structures, where the very soluble N-terminal domain (NT) forms the shell. We hypothesize that fusion to NT could similarly solubilize non-spidroin proteins, and design a charge-reversed mutant (NT*) that is pH insensitive, stabilized and hypersoluble compared to wild-type NT...
May 23, 2017: Nature Communications
https://www.readbyqxmd.com/read/28508363/glycoproteins-enrichment-and-lc-ms-ms-glycoproteomics-in-central-nervous-system-applications
#10
Rui Zhu, Ehwang Song, Ahmed Hussein, Firas H Kobeissy, Yehia Mechref
Proteins and glycoproteins play important biological roles in central nervous systems (CNS). Qualitative and quantitative evaluation of proteins and glycoproteins expression in CNS is critical to reveal the inherent biomolecular mechanism of CNS diseases. This chapter describes proteomic and glycoproteomic approaches based on liquid chromatography/tandem mass spectrometry (LC-MS or LC-MS/MS) for the qualitative and quantitative assessment of proteins and glycoproteins expressed in CNS. Proteins and glycoproteins, extracted by a mass spectrometry friendly surfactant from CNS samples, were subjected to enzymatic (tryptic) digestion and three down-stream analyses: (1) a nano LC system coupled with a high-resolution MS instrument to achieve qualitative proteomic profile, (2) a nano LC system combined with a triple quadrupole MS to quantify identified proteins, and (3) glycoprotein enrichment prior to LC-MS/MS analysis...
2017: Methods in Molecular Biology
https://www.readbyqxmd.com/read/28503550/design-of-surfactant-protein-b-peptide-mimics-based-on-the-saposin-fold-for-synthetic-lung-surfactants
#11
Frans J Walther, Larry M Gordon, Alan J Waring
Surfactant protein (SP)-B is a 79-residue polypeptide crucial for the biophysical and physiological function of endogenous lung surfactant. SP-B is a member of the Saposin or Saposin-like proteins (SAPLIP) family of proteins that share an overall three-dimensional folding pattern based on secondary structures and disulfide connectivity and exhibit a wide diversity of biological functions. Here we review the synthesis, molecular biophysics and activity of synthetic analogs of Saposin proteins designed to mimic those interactions of the parent proteins with lipids that enhance interfacial activity...
September 2016: Biomedicine Hub
https://www.readbyqxmd.com/read/28493723/influence-of-conventional-surfactants-on-the-self-assembly-of-a-bola-type-amphiphilic-peptide
#12
Yueying Cao, Dong Wang, Peng Zhou, Yurong Zhao, Yawei Sun, Jiqian Wang
Structural and morphological regulation is a distinctly important topic in peptide self-assembly, and is also regarded as the fundamental point in peptide-based biomaterials development. In this paper, we showed that adding anionic surfactant SDS to a bola amphiphilic peptide KI4K could result in the reconstruction of β-sheet secondary structure besides the changes in self-assembly morphologies from nanotubes to helical ribbons, nanofibers, or straight nanotapes according to the negatively stained transmission electron microscopy, atomic force microscopy, circular dichroism spectroscopy, and Fourier transform infrared spectroscopy results...
June 6, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28490071/recovery-of-a-bacteriocin-like-inhibitory-substance-from-pediococcus-acidilactici-kp10-using-surfactant-precipitation
#13
Fadzlie Wong Faizal Wong, Arbakariya B Ariff, Sahar Abbasiliasi, David C Stuckey
Bacteriocin is an important peptide which can be used as an anti-microbial agent in food. However, simpler and more cost-effective purification methods need to be developed compared to chromatography to enhance its commercial viability. Surfactant precipitation was employed for the first time to purify bacteriocin-like inhibitory substance (BLIS) from a fermentation broth of Pediococcus acidilactici Kp10, and the amount precipitated was investigated as a function of anionic surfactant (AOT) concentration, and pH...
October 1, 2017: Food Chemistry
https://www.readbyqxmd.com/read/28482785/microemulsions-for-protein-delivery-loading-optimization-and-stability
#14
Diego R Perinelli, Marco Cespi, Stefania Pucciarelli, Silvia Vincenzetti, Luca Casettari, Jenny K W Lam, Serena Logrippo, Elisa Canala, Mahmoud E Soliman, Giulia Bonacucina, Giovanni F Palmieri
BACKGROUND: Microemulsions are attractive delivery systems for therapeutic proteins and peptides due to their ability to enhance bioavailability. Although different proteins and peptides have been successfully delivered through such ternary systems, no information can be found about protein loading and the formulation stability when such microemulsions are prepared with pharmaceutically-approved oils and surfactants. The aim of this work was to optimise a ternary system consisting of water/ethyl oleate/Span 80-Tween 80 and to determine its protein loading capacity and stability, using bovine serum albumin (BSA) as a model of biomolecule...
May 7, 2017: Current Pharmaceutical Biotechnology
https://www.readbyqxmd.com/read/28466946/giant-vesicles-from-rehydrated-crude-mixtures-containing-unexpected-mixtures-of-amphiphiles-formed-under-plausibly-prebiotic-conditions
#15
Michele Fiore, Warren Madanamoothoo, Alexandra Berlioz-Barbier, Ofelia Maniti, Agnès Girard-Egrot, René Buchet, Peter Strazewski
Giant lipid vesicles resemble compartments of biological cells, mimicking them in their dimension, membrane structure and partly in their membrane composition. The spontanenous appearance of closed membranes composed of bilayers of self-assembling amphiphiles was likely a prerequisite for Darwinian competitive behavior to set in at the molecular level. Such compartments should be dynamic in their membrane composition (evolvable), and sufficiently stable to harbor macromolecules (leak-free), yet semi-permeable for reactive small molecules to get across the membrane (stay away from chemical equilibrium)...
May 16, 2017: Organic & Biomolecular Chemistry
https://www.readbyqxmd.com/read/28465315/a-first-in-human-clinical-study-of-a-new-sp-b-and-sp-c-enriched-synthetic-surfactant-chf5633-in-preterm-babies-with-respiratory-distress-syndrome
#16
David G Sweet, Mark A Turner, Zbyněk Straňák, Richard Plavka, Paul Clarke, Ben J Stenson, Dominique Singer, Rangmar Goelz, Laura Fabbri, Guido Varoli, Annalisa Piccinno, Debora Santoro, Christian P Speer
OBJECTIVE: CHF5633 (Chiesi Farmaceutici S.p.A., Parma, Italy) is the first fully synthetic surfactant enriched by peptide analogues of two human surfactant proteins. We planned to assess safety and tolerability of CHF5633 and explore preliminary efficacy. DESIGN: Multicentre cohort study. PATIENTS: Forty infants from 27(+0) to 33(+6) weeks gestation with respiratory distress syndrome requiring fraction of inspired oxygen (FiO2) ≥0.35 were treated with a single dose of CHF5633 within 48 hours after birth...
May 2, 2017: Archives of Disease in Childhood. Fetal and Neonatal Edition
https://www.readbyqxmd.com/read/28438316/multiple-modes-of-capillary-electrophoresis-applied-in-peptide-nucleic-acid-related-study
#17
Xiaoqian Wang, Youhao Hu, Feng Qu, Rizwan Ullah Khan
Peptide Nucleic Acid (PNA) is a nucleic acid analogue, whose neutrally charged and hydrophobic backbone makes it more stable in vivo, so it might act as a potentially better protein probe as compared to aptamer. Currently the investigation of PNA and protein interaction is scarce. In this research, multiple modes of capillary electrophoresis were established and applied for PNA characterization and its interaction with ssDNA and protein. A 15-mer PNA having the same nucleobase sequence as 15-mer anti-thrombin DNA aptamer was chosen as PNA model for this study, its pI (7...
April 17, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28437109/structure-of-the-fundamental-lipopeptide-surfactin-at-the-air-water-interface-investigated-by-sum-frequency-generation-spectroscopy
#18
S A Goussous, M T L Casford, A C Murphy, G P C Salmond, F J Leeper, P B Davies
The lipopeptide surfactin produced by certain strains of Bacillus subtilis is a powerful biosurfactant possessing potentially useful antimicrobial properties. In order to better understand its surface behavior, we have used surface sensitive sum frequency generation (SFG) vibrational spectroscopy in the C-H and C═O stretching regions to determine its structure at the air/water interface. Using surfactin with the leucine groups of the peptide ring perdeuterated, we have shown that a majority of the SFG signals arise from the 4 leucine residues...
May 4, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28413467/calcitonin-gene-related-peptide-protects-type-ii-alveolar-epithelial-cells-from-hyperoxia-induced-dna-damage-and-cell-death
#19
Hongmin Fu, Tiesong Zhang, Rongwei Huang, Zhen Yang, Chunming Liu, Ming Li, Fang Fang, Feng Xu
Hyperoxia therapy for acute lung injury (ALI) may unexpectedly lead to reactive oxygen species (ROS) production and cause additional ALI. Calcitonin gene-related peptide (CGRP) is a 37 amino acid neuropeptide that regulates inflammasome activation. However, the role of CGRP in DNA damage during hyperoxia is unclear. Therefore, the aim of the present study was to investigate the effects of CGRP on DNA damage and the cell death of alveolar epithelial type II cells (AEC II) exposed to 60% oxygen. AEC II were isolated from 19-20 gestational day fetal rat lungs and were exposed to air or to 60% oxygen during treatment with CGRP or the specific CGRP receptor antagonist CGRP8-37...
April 2017: Experimental and Therapeutic Medicine
https://www.readbyqxmd.com/read/28412812/an-ionstar-experimental-strategy-for-ms1-ion-current-based-quantification-using-ultra-high-field-orbitrap-reproducible-in-depth-and-accurate-protein-measurement-in-larger-cohorts
#20
Xiaomeng Shen, Shichen Shen, Jun Li, Qiang Hu, Lei Nie, Chengjian Tu, Xue Wang, Benjamin Orsburn, Jianmin Wang, Jun Qu
In-depth and reproducible protein measurement in many biological samples is often critical for pharmaceutical/biomedical proteomics but remains challenging. MS1-based quantification using quadrupole/ultra-high-field Orbitrap(Q/UHF-Orbitrap) holds great promise, but the critically important experimental approaches enabling reliable large-cohort analysis have long been overlooked. Here we described an IonStar experimental strategy achieving excellent quantitative quality of MS1 quantification. Key features include: i)an optimized, surfactant-aided sample preparation approach provides highly efficient(>75%recovery) and reproducible(<15%CV) peptide recovery across large cell/tissue cohorts; ii)a long column with modest gradient length (e...
April 16, 2017: Journal of Proteome Research
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