bluuebunny/crossref_metadata_2025_split huggingface dataset:
Chemoselective ligation techniques: Modern applications of time‐honored chemistry
Authors: Tiefenbrunn Theresa K. , Dawson Philip E. 
Published: January 2010

AbstractChemoselective ligation techniques enable the selective modification of proteins and other biomolecules in dilute aqueous solution. Importantly, these reactions occur at or near physiological pH and are compatible with the complex array of functional groups commonly found in biological macromolecules including proteins, nucleotides, and carbohydrates, allowing conjugation reactions to be carried out on unprotected substrates. Recently, a growing number of reactions with established utility in synthetic organic chemistry have been shown to have surprising utility in the context of biological molecules in aqueous media. In this review we highlight several promising reactions that may have widespread applicability in the generation of new materials based on biological macromolecules. © 2010 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 91:95–106, 2010.This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Building fibrous biomaterials from α‐helical and collagen‐like coiled‐coil peptides
Authors: Woolfson Derek N. 
Published: January 2010

AbstractOver the decade and a half, interest has soared in the development of peptide‐based biomaterials and their potential applications in biotechnology. This review outlines the advances during this time in the construction of biomaterials based on the α‐helical coiled‐coil and collagen‐like peptides. These structures and the resulting designs are distinct from the more commonly used β‐structured peptides, which often lead to hydrogels comprising amyloid‐like fibrils. The review covers basic design rules for these helical assemblies, and the various fibrous biomaterials that can be accomplished with them, which include rigid structures with straight, branched, or networked structures, decorated and functionalized systems, and most recently flexible fibers and entangled hydrogel networks. This plethora of α‐helix‐based biomaterials, together with more recent collagen‐like assemblies, that are emerging from various laboratories complement those developed using β‐structured peptides, and open exciting new avenues for biomaterials research and potential new application areas. © 2010 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 94:118–127, 2010.This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Synthesis by native chemical ligation and crystal structure of human CCL2
Authors: Grygiel Tami L. R. , Teplyakov Alexey , Obmolova Galina , Stowell Nicole , Holland Reannon , Nemeth Jennifer F. , Pomerantz Steven C. , Kruszynski Marian , Gilliland Gary L. 
Published: January 2010

AbstractThe protein human CC chemokine ligand 2 (CCL2, also known as monocyte chemoattractant protein 1 or MCP‐1) has been synthesized using a combination of solid phase peptide synthesis (SPPS) and native chemical ligation (NCL). The thioester‐peptide segment was synthesized using the sulfonamide safety‐catch linker and 9‐fluorenylmethoxycarbonyl (Fmoc) SPPS, and pseudoproline dipeptides were used to facilitate the synthesis of both CCL2 fragments. After assembly of the full‐length peptide chain by NCL, a glutathione redox buffer was used to fold and oxidize the CCL2 protein. Synthetic human CCL2 binds to and activates the CCR2 receptor on THP‐1 cells, as expected. CCL2 was crystallized and the structure was determined by X‐ray diffraction at 1.9‐Å resolution. The structure of the synthetic protein is very similar to that of a previously reported structure of recombinant human CCL2, although the crystal form is different. The functional CCL2 dimer for the crystal structure reported here is formed around a crystallographic twofold axis. The dimer interface involves residues Val9‐Thr10‐Cys11, which form an intersubunit antiparallel β‐sheet. Comparison of the CCL2 dimers in different crystal forms indicates a significant flexibility of the quaternary structure. To our knowledge, this is one of the first crystal structures of a protein prepared using the sulfonamide safety‐catch linker and NCL. © 2010 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 94: 350–359, 2010.This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Microporous cell‐laden hydrogels for engineered tissue constructs
Authors: Park Jae Hong , Chung Bong Geun , Lee Won Gu , Kim Jinseok , Brigham Mark D. , Shim Jaesool , Lee Seunghwan , Hwang Chang Mo , Durmus Naside Gozde , Demirci Utkan , Khademhosseini Ali 
Published: January 2010

AbstractIn this article, we describe an approach to generate microporous cell‐laden hydrogels for fabricating biomimetic tissue engineered constructs. Micropores at different length scales were fabricated in cell‐laden hydrogels by micromolding fluidic channels and leaching sucrose crystals. Microengineered channels were created within cell‐laden hydrogel precursors containing agarose solution mixed with sucrose crystals. The rapid cooling of the agarose solution was used to gel the solution and form micropores in place of the sucrose crystals. The sucrose leaching process generated homogeneously distributed micropores within the gels, while enabling the direct immobilization of cells within the gels. We also characterized the physical, mechanical, and biological properties (i.e., microporosity, diffusivity, and cell viability) of cell‐laden agarose gels as a function of engineered porosity. The microporosity was controlled from 0% to 40% and the diffusivity of molecules in the porous agarose gels increased as compared to controls. Furthermore, the viability of human hepatic carcinoma cells that were cultured in microporous agarose gels corresponded to the diffusion profile generated away from the microchannels. Based on their enhanced diffusive properties, microporous cell‐laden hydrogels containing a microengineered fluidic channel can be a useful tool for generating tissue structures for regenerative medicine and drug discovery applications. Biotechnol. Bioeng. 2010; 106: 138–148. © 2010 Wiley Periodicals, Inc.
Discovery and analysis of novel metabolic pathways for the biosynthesis of industrial chemicals: 3‐hydroxypropanoate
Authors: Henry Christopher S. , Broadbelt Linda J. , Hatzimanikatis Vassily 
Published: January 2010

AbstractSustainable microbial production of high‐value organic compounds such as 3‐hydroxypropanoate (3HP) is becoming an increasingly attractive alternative to organic syntheses that utilize petrochemical feedstocks. We applied the Biochemical Network Integrated Computational Explorer (BNICE) framework to the automated design and evaluation of novel biosynthetic routes for the production of 3HP from pyruvate. Among the pathways generated by the BNICE framework were all of the known pathways for the production of 3HP as well as numerous novel pathways. The pathways generated by BNICE were ranked based on four criteria: pathway length, thermodynamic feasibility, maximum achievable yield to 3HP from glucose, and maximum achievable activity at which 3HP can be produced. Four pathways emerged from this ranking as the most promising for the biosynthesis of 3HP, and three of these pathways, including the shortest pathways discovered, were novel. We also discovered novel routes for the biosynthesis of 28 commercially available compounds that are currently produced exclusively through organic synthesis. Examination of the optimal pathways for the biosynthesis of these 28 compounds in E. coli revealed pyruvate and succinate to be ideal intermediates for achieving high product yields from glucose. Biotechnol. Bioeng. 2010; 106: 462–473. © 2010 Wiley Periodicals, Inc.
A biohybrid artificial lung prototype with active mixing of endothelialized microporous hollow fibers
Authors: Polk Alexa A. , Maul Timothy M. , McKeel Daniel T. , Snyder Trevor A. , Lehocky Craig A. , Pitt Bruce , Stolz Donna Beer , Federspiel William J. , Wagner William R. 
Published: January 2010

AbstractAcute respiratory distress syndrome (ARDS) affects nearly 150,000 patients per year in the US, and is associated with high mortality (≈40%) and suboptimal options for patient care. Mechanical ventilation and extracorporeal membrane oxygenation are limited to short‐term use due to ventilator‐induced lung injury and poor biocompatibility, respectively. In this report, we describe the development of a biohybrid lung prototype, employing a rotating endothelialized microporous hollow fiber (MHF) bundle to improve blood biocompatibility while MHF mixing could contribute to gas transfer efficiency. MHFs were surface modified with radio frequency glow discharge (RFGD) and protein adsorption to promote endothelial cell (EC) attachment and growth. The MHF bundles were placed in the biohybrid lung prototype and rotated up to 1,500 revolutions per minute (rpm) using speed ramping protocols to condition ECs to remain adherent on the fibers. Oxygen transfer, thrombotic deposition, and EC p‐selectin expression were evaluated as indicators of biohybrid lung functionality and biocompatibility. A fixed aliquot of blood in contact with MHF bundles rotated at either 250 or 750 rpm reached saturating pO2 levels more quickly with increased rpm, supporting the concept that fiber rotation would positively contribute to oxygen transfer. The presence of ECs had no effect on the rate of oxygen transfer at lower fiber rpm, but did provide some resistance with increased rpm when the overall rate of mass transfer was higher due to active mixing. RFGD followed by fibronectin adsorption on MHFs facilitated near confluent EC coverage with minimal p‐selectin expression under both normoxic and hyperoxic conditions. Indeed, even subconfluent EC coverage on MHFs significantly reduced thrombotic deposition adding further support that endothelialization enhances, blood biocompatibility. Overall these findings demonstrate a proof‐of‐concept that a rotating endothelialized MHF bundle enhances gas transfer and biocompatibility, potentially producing safer, more efficient artificial lungs. Biotechnol. Bioeng. 2010; 106: 490–500. © 2010 Wiley Periodicals, Inc.
The oxygen evolution methodology affects photosynthetic rate measurements of microalgae in well‐defined light regimes
Authors: Brindley Celeste , Acién Francisco G. , Fernández‐Sevilla José M. 
Published: January 2010

AbstractDesigning photobioreactors correctly is a must for the success of microalgal mass production. Optimal photobioreactor design requires a precise knowledge of photosynthesis dynamics in fluctuating light conditions and hence a method for the measurement of photosynthetic rates in specific light regimes. However, it is not uncommon in literature that experimental protocols used to obtain oxygen generation rates are described ambiguously and the reported rates of photosynthesis vary widely depending on the methodology. Additionally, quite a number of methods overlook certain aspects that can affect the estimated rates significantly, and can therefore affect photobioreactor design. We have developed a method based on oxygen evolution measurements that accurately determines photosynthetic rates under well‐defined light regimes. Our experimental protocol takes into account most of the issues that can affect the rates of oxygen generation, such as depletion of nutrients during the measurements and precision of the measurements. We have focused on the basic applications in photobioreactor design and used a dynamic model of photosynthesis to analyze our results and compare them with available published data. The results suggest that our oxygen evolution method is consistent. Biotechnol. Bioeng. 2010;106: 228–237. © 2010 Wiley Periodicals, Inc.
Oxygen plasma‐treated thermoresponsive polymer surfaces for cell sheet engineering
Authors: Shimizu Kazunori , Fujita Hideaki , Nagamori Eiji 
Published: January 2010

AbstractAlthough cell sheet tissue engineering is a potent and promising method for tissue engineering, an increase of mechanical strength of a cell sheet is needed for easy manipulation of it during transplantation or 3D tissue fabrication. Previously, we developed a cell sheet–polymer film complex that had enough mechanical strength that can be manipulated even by tweezers (Fujita et al., 2009. Biotechnol Bioeng 103(2): 370–377). We confirmed the polymer film involving a temperature sensitive polymer and extracellular matrix (ECM) proteins could be removed by lowering temperature after transplantation, and its potential use in regenerative medicine was demonstrated. However, the use of ECM proteins conflicted with high stability in long‐term storage and low cost. In the present study, to overcome these drawbacks, we employed the oxygen plasma treatment instead of using the ECM proteins. A cast and dried film of thermoresponsive poly‐N‐isopropylacrylamide (PNIPAAm) was fabricated and treated with high‐intensity oxygen plasma. The cells became possible to adhere to the oxygen plasma‐treated PNIPAAm surface, whereas could not to the inherent surface of bulk PNIPAAm without treatment. Characterizations of the treated surface revealed the surface had high stability. The surface roughness, wettability, and composition were changed, depending on the plasma intensity. Interestingly, although bulk PNIPAAm layer had thermoresponsiveness and dissolved below lower critical solution temperature (LCST), it was found that the oxygen plasma‐treated PNIPAAm surface lost its thermoresponsiveness and remained insoluble in water below LCST as a thin layer. Skeletal muscle C2C12 cells could be cultured on the oxygen plasma‐treated PNIPAAm surface, a skeletal muscle cell sheet with the insoluble thin layer could be released in the medium, and thus the possibility of use of the cell sheet for transplantation was demonstrated. Biotechnol. Bioeng. 2010;106: 303–310. © 2010 Wiley Periodicals, Inc.
Targeted binding of PEG‐lipid modified polymer ultrasound contrast agents with tiered surface architecture
Authors: Duncanson Wynter J. , Oum Kelleny , Eisenbrey John R. , Cleveland Robin O. , Wheatley Margaret A. , Wong Joyce Y. 
Published: January 2010

AbstractIn order for site‐directed polymer ultrasound contrast agents (UCAs) to provide acoustic enhancement at disease sites to distinguish normal tissue from diseased tissue, the surface of these agents must be functionalized with mixtures of grafted polymers. Here a combination of longer liganded polyethylene glycol (PEG)‐lipids and shorter unliganded PEG‐lipids were introduced into the oil phase of a modified solvent evaporation double emulsion method for preparing UCAs. UCAs with different lengths of both liganded and unliganded lipids were imaged under 7.5 MHz ultrasound. The B‐mode image brightness of the mixed PEG‐lipid UCAs was within 1 dB the brightness of the unliganded surface. After 15 min of continuous insonation, 70% of the contrast signal remained. The peptide arginine–glycine–aspartic acid (RGD) was added to the surface of these UCAs through a biotin–avidin linkage and binding was assessed under static and shear conditions. Binding was significant after 30 min of static incubation and the adherence of the UCA increased under shear flow from 3 UCA/cell (static) to 5 UCA/cell (shear). Biotechnol. Bioeng. 2010; 106: 501–506. © 2010 Wiley Periodicals, Inc.
Larvicidal and Structure–Activity Studies of Natural Phenylpropanoids and Their Semisynthetic Derivatives against the Tobacco Armyworm Spodoptera litura (Fab.) (Lepidoptera: Noctuidae)
Authors: Bhardwaj Anu , Kumar Tewary Dhananjay , Kumar Rakesh , Kumar Vinod , Kumar Sinha Arun , Shanker Adarsh 
Published: January 2010

AbstractThe larvicidal activity of 18 phenylpropanoids, 1–18, including phenylpropenoate, phenylpropenal, phenylpropene, and their semisynthetic analogues, were evaluated against the tobacco armyworm, Spodoptera litura (Fab.), to identify promising structures with insecticidal activity. Amongst various phenylpropanoids, isosafrole, a phenylpropene, showed the best activity, with an LC50 value of 0.6 μg/leaf cm2, followed by its hydrogenated derivative dihydrosafrole (LC50=2.7 μg/leaf cm2). The overall larvicidal activity of various phenylpropene derivatives was observed in the following order: isosafrole (6)>dihydrosafrole (16)>safrole (12)>anethole (4)>methyl eugenol (11)>eugenol (13)>β‐asarone (8)>dihydroasarone (18)>dihydroanethole (15). Dihydrosafrole might be a promising compound, although presenting a lower larvicidal activity than isosafrole, because of its better stability and resistance to oxidative degradation (due to the removal of the extremely reactive olefinic bond) in comparison to isosafrole. Such structure–activity relationship studies promote the identification of lead structures from natural sources for the development of larvicidal products against S. litura and related insect pests.
Benzophenones from Guignardia sp. IFB‐E028, an Endophyte on Hopea hainanensis
Authors: Wang Feng‐Wu , Ye Yong‐Hao , Ding Hui , Chen Yun‐Xi , Tan Ren‐Xiang , Song Yong‐Chun 
Published: January 2010

AbstractThe first natural S‐containing benzophenone dimer, named guignasulfide (3), was isolated from the culture of Guignardia sp. IFB‐E028, an endophytic fungus residing in healthy leaves of Hopea hainanensis. Its structure was determined through correlative analyses of its MS, 1D‐ and 2D‐NMR spectroscopic data. Two other known benzophenone derivatives, monomethylsulochrin and rhizoctonic acid (1 and 2, resp.) were also isolated. Guignasulfide (3) was more active against the human liver cancer cell line HepG2 (IC50 value: 5.2±0.4 μM) than metabolites 1 and 2 (IC50 values: 63.5±0.6 and 60.2±0.5 μM); compounds 1–3 showed also moderately inhibitory effects on the human bacterial pathogen Helicobacter pylori with MIC values of 28.9±0.1, 60.2±0.4, and 42.9±0.5 μM, respectively.
Who Is the King? The α‐Hydroxy‐β‐oxo‐α,β‐enone Moiety or the Catechol B Ring: Relationship between the Structure of Quercetin Derivatives and Their Pro‐Oxidative Abilities
Authors: Liu Pei‐Yan , Li Kun , Zhang Ji , Zhang Da‐Wei , Lin Hong‐Hui , Yu Xiao‐Qi 
Published: January 2010

AbstractQuercetin and other flavonoids have been reported to exhibit both antioxidant and pro‐oxidant properties. Most studies about the pro‐oxidative ability were conducted in the presence of metal ions, and the essential functional moiety of quercetin responsible for the pro‐oxidative effect is still unclear. In this study, we evaluated the pro‐oxidative abilities in the absence of metal ions of two quercetin derivatives, i.e., quercetin‐3′‐O‐β‐D‐glucoside (1) and quercetin‐3‐O‐β‐D‐glucoside (2), by assessing DNA cleavage and HO.‐radical production. The binding mode between these compounds and DNA was studied by fluorescence and viscometric titrations. The results showed that 1 can efficiently induce oxidative damage to plasmid DNA, while 2 shows poor activity. Both 1 and 2 bind to DNA via groove‐binding. These results proved that the α‐hydroxy‐β‐oxo‐α,β‐enone moiety contributes to the pro‐oxidative activity of quercetin.
Chiral Piperazine‐2,5‐dione Derivatives as Effective α‐Glucosidase Inhibitors. Part 4
Authors: Arcelli Antonio , Balducci Daniele , Porzi Gianni , Sandri Monica 
Published: January 2010

AbstractThe potential to inhibit α‐ and β‐glucosidases of a series of chiral piperazine‐2,5‐dione derivatives was investigated. Three of the seven compounds tested, viz., 1, 5b, and 5c, showed to be non competitive inhibitors of α‐glucosidase, whereas they exhibited very low inhibitory activity towards β‐glucosidase. The most active compound, 5c (KI of α‐glucosidase=5 μm), had a 100‐fold α‐glucosidase/β‐glucosidase inhibitor selectivity.
The Thioesterase Bhp is Involved in the Formation of β‐Hydroxytyrosine during Balhimycin Biosynthesis in Amycolatopsis balhimycina
Authors: Mulyani Sri , Egel Ellen , Kittel Claudia , Turkanovic Suada , Wohlleben Wolfgang , Süssmuth Roderich D. , van Pée Karl‐Heinz 
Published: January 2010

AbstractThe putative hydrolase gene bhp from the balhimycin biosynthetic gene cluster has been cloned and overexpressed in Escherichia coli. The corresponding enzyme Bhp was purified to homogeneity by nickel‐chelating chromatography and characterized. Although Bhp has sequence similarities to hydrolases with “haloperoxidase”/perhydrolase activity, it did not show any enzymatic activity with standard “haloperoxidase”/perhydrolase substrates (e.g., monochlorodimedone and phenol red), nonspecific esterase substrates (such as p‐nitrophenyl acetate, p‐nitrophenyl phosphate and S‐thiophenyl acetate) or the model lactonase substrate dihydrocoumarin. However, Bhp could be shown to catalyse the hydrolysis of S‐β‐hydroxytyrosyl‐N‐acetyl cysteamine thioester (β‐OH‐Tyr‐SNAC) with 15 times the efficiency of S‐L‐tyrosyl‐N‐acetyl cysteamine thioester (L‐Tyr‐SNAC). This is in agreement with the suggestion that Bhp is involved in balhimycin biosynthesis, during which it was supposed to catalyse the hydrolysis of β‐OH‐Tyr‐S‐PCP (PCP=peptidyl carrier protein) to free β‐hydroxytyrosine (β‐OH‐Tyr) and strongly suggests that Bhp is a thioesterase with high substrate specificity for PCP‐bound β‐OH‐Tyr and not a “haloperoxidase”/perhydrolase or nonspecific esterase.
Distal embolization after net protective stent (MGUARD™) implantation in a degenerated saphenous vein graft lesion
Authors: Yassin Ihab , Thuesen Leif 
Published: January 2010

AbstractWe describe a case of distal protection failure using the net protective stent system, MGUARD™ (InspireMD, Tel Aviv, Israel), in a degenerated saphenous vein graft (SVG) lesion. © 2010 Wiley‐Liss, Inc.
A novel concept in endovascular stenting for the treatment of old severely degenerated saphenous vein graft in the urgent setting
Authors: Hendler Alberto , Minha Saar , Krakover and Ricardo 
Published: January 2010

AbstractWe report a critically ill‐patient admitted for NSTEMI with acute pulmonary congestion, showing at urgent cardiac catheterization a severely diseased saphenous vein graft as the culprit vessel, with huge atherothrombotic burden. The graft was successfully revascularized by the implantation of 4 M‐Guard stent (for proximal to distal) creating a full metal jacket. The M‐Guard technology consists on a stainless steel platform wrapped by a micron‐level polymer net, that seamlessly expands when the stent is deployed, providing protection from embolic showers. © 2010 Wiley‐Liss, Inc.
Transcatheter aortic valve replacement
Authors: Dainese Luca , Fusari Melissa , Biglioli Paolo 
Published: January 2010

AbstractWe report a new technique of the partially and sequentially gonflage of the transcatheter balloon valve, the so called dog bone shaped technique, which allowed us to approach the aortic root by inflating the valve balloon in two different times, stabilizing the heart and deplacing the valve. © 2010 Wiley‐Liss, Inc.