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https://www.readbyqxmd.com/read/29150961/modulation-of-igg1-immunoeffector-function-by-glycoengineering-of-the-gdp-fucose-biosynthesis-pathway
#1
Ronan M Kelly, Ronald L Kowle, Zhirui Lian, Beth A Strifler, Derrick R Witcher, Bhavin S Parekh, Tongtong Wang, Christopher C Frye
Cross-linking of the Fcγ receptors expressed on the surface of hematopoietic cells by IgG immune complexes triggers the activation of key immune effector mechanisms, including antibody-dependent cell mediated cytotoxicity (ADCC). A conserved N-glycan positioned at the N-terminal region of the IgG CH 2 domain is critical in maintaining the quaternary structure of the molecule for Fcγ receptor engagement. The removal of a single core fucose residue from the N-glycan results in a considerable increase in affinity for FcγRIIIa leading to an enhanced receptor-mediated immunoeffector function...
November 18, 2017: Biotechnology and Bioengineering
https://www.readbyqxmd.com/read/29148757/cross-linked-artificial-enzyme-crystals-as-heterogeneous-catalysts-for-oxidation-reactions
#2
Sarah Lopez, Laurianne Rondot, Chloé Leprêtre, Caroline Marchi-Delapierre, Stéphane Ménage, Christine Cavazza
Designing systems that merge the advantages of heterogeneous catalysis, enzymology and molecular catalysis represents the next major goal for sustainable chemistry. Cross-linked enzyme crystals display most of these essential assets (well-designed mesoporous support, protein selectivity, molecular recognition of substrates). Nevertheless, a lack of reaction diversity, particularly in the field of oxidation, remains a constraint for their increased use in the field. Here, thanks to the design of cross-linked artificial non-heme iron oxygenase crystals, we filled this gap by developing bio-based heterogeneous catalysts capable of oxidizing carbon-carbon double bonds...
November 17, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/29148599/hierarchical-porous-phenolic-resin-and-its-supported-pd-catalyst-for-suzuki-miyaura-reactions-in-water-medium
#3
Gaoyang Deng, Zhonggang Wang
The motivation of this work is to build micro and mesopores within phenolic resins to extend their applications to the heterogeneous catalysis field. For this purpose, porous hyper-cross-linked phenolic resin (PFN-P) with Brunauer-Emmett-Teller (BET) surface area of 775 m(2) g(-1) is synthesized through one-step polycondensation from tri(4-formylphenyl)phosphine and 2,5-dihydroxy-1,4-benzoquinone, which simultaneously contains abundant hydroxyl and triphenylphosphine moieties in the network. The resultant palladium-coordinated Pd@PFN-P possesses hierarchical porous structure with pore sizes ranging from 1...
November 17, 2017: Macromolecular Rapid Communications
https://www.readbyqxmd.com/read/29148103/extracytoplasmic-function-sigma-factor-%C3%AF-d-confers-resistance-to-environmental-stress-by-enhancing-mycolate-synthesis-and-modifying-peptidoglycan-structures-in-corynebacterium-glutamicum
#4
Koichi Toyoda, Inui Masayuki
Mycolates are α-branched, β-hydroxylated, long-chain fatty acid specifically synthesized in bacteria in the suborder Corynebacterineae of the phylum Actinobacteria. They form an outer membrane, which functions as a permeability barrier and confers pathogenic mycobacteria to resistance to antibiotics. Although the mycolate biosynthetic pathway has been intensively studied, knowledge of transcriptional regulation of genes involved in this pathway is limited. Here we report that the extracytoplasmic function sigma factor σ(D) is a key regulator of the mycolate synthetic genes in Corynebacterium glutamicum in the suborder...
November 17, 2017: Molecular Microbiology
https://www.readbyqxmd.com/read/29147993/preparation-and-characterization-of-gelatin-sericin-carboxymethyl-chitosan-medical-tissue-glue
#5
Min Liang, Zhenzhu Li, Cengceng Gao, Fuping Wang, Zhongmin Chen
BACKGROUND: The development and application of medical glue has been continuously expanding and advancing. However, there are few glues that combine low-cost with excellent biocompatibility. METHODS: We have prepared a medical tissue glue using a gelatin (Gel), sericin (SS) and carboxymethyl chitosan (CMCS) blend solution, cross-linked with 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC). The combination's characteristics and microstructure morphology were observed by Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscope (SEM)...
November 16, 2017: Journal of Applied Biomaterials & Functional Materials
https://www.readbyqxmd.com/read/29147682/synthesis-and-application-of-injectable-bioorthogonal-dendrimer-hydrogels-for-local-drug-delivery
#6
Leyuan Xu, Remy C Cooper, Juan Wang, W Andrew Yeudall, Hu Yang
We developed novel dendrimer hydrogels (DH)s on the basis of bioorthogonal chemistry, in which polyamidoamine (PAMAM) dendrimer generation 4.0 (G4) functionalized with strained alkyne dibenzocyclooctyne (DBCO) via PEG spacer (Mn = 2,000 g/mol) underwent strain-promoted azide-alkyne cycloaddition (SPAAC) with polyethylene glycol bisazide (PEG-BA) (Mn= 20,000 g/mol) to generate a dendrimer-PEG cross-linked network. This platform offers a high degree of functionality and modularity. A wide range of structural parameters including dendrimer generation, degree of PEGylation, loading density of clickable DBCO groups, PEG-BA chain length as well as the ratio of clickable dendrimer to PEG-BA and their concentrations can be readily manipulated to tune chemical and physical properties of DHs...
August 14, 2017: ACS Biomaterials Science & Engineering
https://www.readbyqxmd.com/read/29147540/catalyst-controlled-polycondensation-of-glycerol-with-diacyl-chlorides-linear-polyesters-from-a-trifunctional-monomer
#7
Ekaterina Slavko, Mark S Taylor
Diarylborinic acids catalyze the formation of linear polyesters from glycerol, a trifunctional, carbohydrate-based monomer. The selective activation of 1,2-diols over isolated alcohols by the organoboron catalyst results in polymers that are essentially free of branching or cross-linking and possess a high fraction of 1,3-enchained glycerol units, as assessed by (1)H and (13)C NMR spectroscopy. The ability to generate well-defined polyester architectures from glycerol is significant in light of the numerous applications of such macromolecules, particularly in the biomedical area...
October 1, 2017: Chemical Science
https://www.readbyqxmd.com/read/29146919/nucleosome-acidic-patch-targeting-binuclear-ruthenium-compounds-induce-aberrant-chromatin-condensation
#8
Gabriela E Davey, Zenita Adhireksan, Zhujun Ma, Tina Riedel, Deepti Sharma, Sivaraman Padavattan, Daniela Rhodes, Alexander Ludwig, Sara Sandin, Benjamin S Murray, Paul J Dyson, Curt A Davey
The 'acidic patch' is a highly electronegative cleft on the histone H2A-H2B dimer in the nucleosome. It is a fundamental motif for protein binding and chromatin dynamics, but the cellular impact of targeting this potentially therapeutic site with exogenous molecules remains unclear. Here, we characterize a family of binuclear ruthenium compounds that selectively target the nucleosome acidic patch, generating intra-nucleosomal H2A-H2B cross-links as well as inter-nucleosomal cross-links. In contrast to cisplatin or the progenitor RAPTA-C anticancer drugs, the binuclear agents neither arrest specific cell cycle phases nor elicit DNA damage response, but rather induce an irreversible, anomalous state of condensed chromatin that ultimately results in apoptosis...
November 17, 2017: Nature Communications
https://www.readbyqxmd.com/read/29146773/glyoxal-as-an-alternative-fixative-to-formaldehyde-in-immunostaining-and-super-resolution-microscopy
#9
Katharina N Richter, Natalia H Revelo, Katharina J Seitz, Martin S Helm, Deblina Sarkar, Rebecca S Saleeb, Elisa D'Este, Jessica Eberle, Eva Wagner, Christian Vogl, Diana F Lazaro, Frank Richter, Javier Coy-Vergara, Giovanna Coceano, Edward S Boyden, Rory R Duncan, Stefan W Hell, Marcel A Lauterbach, Stephan E Lehnart, Tobias Moser, Tiago Outeiro, Peter Rehling, Blanche Schwappach, Ilaria Testa, Bolek Zapiec, Silvio O Rizzoli
Paraformaldehyde (PFA) is the most commonly used fixative for immunostaining of cells, but has been associated with various problems, ranging from loss of antigenicity to changes in morphology during fixation. We show here that the small dialdehyde glyoxal can successfully replace PFA Despite being less toxic than PFA, and, as most aldehydes, likely usable as a fixative, glyoxal has not yet been systematically tried in modern fluorescence microscopy. Here, we tested and optimized glyoxal fixation and surprisingly found it to be more efficient than PFA-based protocols...
November 16, 2017: EMBO Journal
https://www.readbyqxmd.com/read/29144723/inorganic-strengthened-hydrogel-membrane-as-regenerative-periosteum
#10
Tianwen Xin, Yong Gu, Ruoyu Cheng, Jincheng Tang, Zhiyong Sun, Wenguo Cui, Liang Chen
Periosteum plays the pivotal role in neomineralization, vascularization and protection during bone tissue regeneration. However, many artificial periosteum focused only on protection and lacked of the osteogenesis and angiogenesis functional capacity. In this study, we developed a novelty inorganic strengthened gelatin hydrogel membrane via inorganic and organic co-cross-linked double network as artificial periosteum for enhancing the durable angiogenesis and osteogenesis in bone reconstruction. Mesoporous bioactive glass nanoparticles (MBGNs) chemically modified with photo-cross-linkable gelatin derivative (GelMA) were further incorporated into GelMA to fabricate an organic/inorganic co-cross-linked hydrogel membrane (GelMA-G-MBGNs)...
November 16, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/29142546/comparison-of-analgesic-effect-of-preoperative-topical-diclofenac-versus-ketorolac-on-postoperative-pain-after-corneal-collagen-cross-linkage
#11
Murtaza Sameen, Muhammad Saim Khan, Asad Habib, Muhammad Amer Yaqub, Mazhar Ishaq
Objective: To compare post-operative pain relieving effect of topical diclofenac 0.1% versus ketorolac 0.5% in Corneal Collagen Cross Linking (CXL) for patients diagnosed with keratoconus. Methods: This randomized controlled trial was carried out for six months from October 2016 to March 2017. We included young patients having keratoconus with k-readings greater than 47D and central corneal thickness more than 400 microns. All the patients received single dose one drop of topical diclofenac 0...
September 2017: Pakistan Journal of Medical Sciences Quarterly
https://www.readbyqxmd.com/read/29142312/understanding-the-anticorrosive-protective-mechanisms-of-modified-epoxy-coatings-with-improved-barrier-active-and-self-healing-functionalities-eis-and-spectroscopic-techniques
#12
Demian I Njoku, Miaomiao Cui, Haigang Xiao, Baihui Shang, Ying Li
The present investigation adopted long-term in-situ electrochemical and spectroscopic approaches to study the combined active, self-healing and passive protective mechanisms of a new class of innovative anti-corrosive coatings based on epoxy doped with clay nanotubes impregnated with active species for the protection of carbon steel in 3.5% NaCl solution. The suitability of the as-received clay nanotubes to encapsulate the active agents was confirmed by different spectroscopic measurements. Tube end stopper with Ferric ion and polymer encapsulation with chitosan cross-linked with glutaraldehyde were adopted to tunnel the release of the active agents loaded into the nanotubes...
November 15, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29140861/sealing-of-corneal-lacerations-using-photoactivated-rose-bengal-dye-and-amniotic-membrane
#13
Timothy A Soeken, Hong Zhu, Sheri DeMartelaere, Brett W Davies, Mirang Kim, Heuy-Ching Wang, James Aden, Rose Grimm, Clemens Alt, Irene E Kochevar, Anthony J Johnson
PURPOSE: Watertight closure of perforating corneoscleral lacerations is necessary to prevent epithelial ingrowth, infection, and potential loss of the eye. Complex lacerations can be difficult to treat, and repair with sutures alone is often inadequate. In this study, we evaluated a potentially sutureless technology for sealing complex corneal and scleral lacerations that bonds the amniotic membrane (AM) to the wound using only green light and rose bengal dye. METHODS: The AM was impregnated with rose bengal and then sealed over lacerations using green light to bond the AM to the deepithelialized corneal surface...
November 14, 2017: Cornea
https://www.readbyqxmd.com/read/29140306/chitosan-spray-dried-microparticles-for-controlled-delivery-of-venlafaxine-hydrochloride
#14
Inmaculada Aranaz, Ines Paños, Carlos Peniche, Ángeles Heras, Niuris Acosta
Venlafaxine controlled drug delivery systems using different matrixes have been tested to reduce undesirable side effects in the treatment of depression. The legal status of chitosan (Cs) in Pharmacy has dramatically improved after its acceptance as excipient in several Pharmacopeias and, therefore, there is great interest in pharmaceutical formulations based on this polymer. In this paper, chitosan microcapsules cross-linked with sodium tripolyphosphate (TPP) for oral delivery of venlafaxine were formulated using the spray drying technique...
November 15, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/29140279/free-standing-and-self-crosslinkable-hybrid-films-by-core-shell-particle-design-and-processing
#15
Steffen Vowinkel, Stephen Paul, Torsten Gutmann, Markus Gallei
The utilization and preparation of functional hybrid films for optical sensing applications and membranes is of utmost importance. In this work, we report the convenient and scalable preparation of self-crosslinking particle-based films derived by directed self-assembly of alkoxysilane-based cross-linkers as part of a core-shell particle architecture. The synthesis of well-designed monodisperse core-shell particles by emulsion polymerization is the basic prerequisite for subsequent particle processing via the melt-shear organization technique...
November 15, 2017: Nanomaterials
https://www.readbyqxmd.com/read/29140252/generation-of-genipin-cross-linked-fibrin-agarose-hydrogels-tissue-like-models-for-tissue-engineering-applications
#16
Fernando Campos, Ana Belen Bonhame-Espinosa, Gerson Vizcaino, Ismael Angel Rodriguez, Daniel Durand-Herrera, Modesto T Lopez-Lopez, Indalecio Sánchez-Montesinos, Miguel Alaminos, María Del Carmen Sánchez-Quevedo, Víctor Carriel
Generation of biomimetic and biocompatible artificial tissues is the basic research objective for tissue engineering (TE). In this sense, the biofabrication of scaffolds that resemble the tissues' extracellular matrix (ECM) is an essential aim in this field. Uncompressed and nanostructured fibrin-agarose hydrogels (FAH and NFAH respectively) emerged as promising scaffold in TE, but its structure and biomechanical properties must be improved in order to broad their TE applications. Here we generated and characterized novel membrane-like models with increased structural and biomechanical properties based on the chemical cross-linking of FAH and NFAH with genipin (GP at 0...
November 15, 2017: Biomedical Materials
https://www.readbyqxmd.com/read/29139530/when-droplets-become-stars-charged-dielectric-droplets-beyond-the-rayleigh-limit
#17
Myong In Oh, Anatoly Malevanets, Maxim Paliy, Daan Frenkel, Styliani Consta
When a nano-drop comprising a single spherical central ion and dielectric solvent is charged above a well-defined threshold, it acquires a stable star morphology. In contrast, conducting droplets, will undergo fission. Here we report combined atomistic molecular dynamics and continuum modelling study of star formation of droplets that contain a highly charged ion. We assume that in the continuum model the dielectric response is linear. In this linear continuum model, which is an extension of Rayleigh model, the energy of the drop is comprised of terms analogous to those in Rayleigh model, which are surface energy and electrostatic energy of dielectric droplet charged by a central point charge...
November 15, 2017: Soft Matter
https://www.readbyqxmd.com/read/29139109/%C3%AE-cyclodextrin-encapsulated-polyphenols-as-effective-antioxidants
#18
Pritam Roy, Amit Kumar Dinda, Susmitnarayan Chaudhury, Swagata Dasgupta
Formation of dityrosine (DT) cross-linkages in proteins is one of the most widely used markers of oxidative stress. Ribonuclease A (RNase A) has 6 Tyr residues and shows a characteristic DT fluorescence peak upon oxidation in addition to major changes in its secondary structure. DT formation can be prevented by using polyphenols (GA, ECG, and EGCG) which are known to have strong antioxidant activity. However, it has been observed that ECG and EGCG initiate protein oligomerization due to protein-polyphenol cross-linkages...
November 15, 2017: Biopolymers
https://www.readbyqxmd.com/read/29138488/structural-basis-of-adaptor-mediated-protein-degradation-by-the-tail-specific-pdz-protease-prc
#19
Ming-Yuan Su, Nilanjan Som, Chia-Yun Wu, Shih-Chieh Su, Yi-Ting Kuo, Lu-Chu Ke, Meng-Ru Ho, Shiou-Ru Tzeng, Ching-Hao Teng, Dominique Mengin-Lecreulx, Manjula Reddy, Chung-I Chang
Peptidoglycan (PG) is a highly cross-linked, protective mesh-like sacculus that surrounds the bacterial cytoplasmic membrane. Expansion of PG is tightly coupled to growth of a bacterial cell and requires hydrolases to cleave the cross-links for insertion of nascent PG material. In Escherichia coli, a proteolytic system comprising the periplasmic PDZ-protease Prc and the lipoprotein adaptor NlpI contributes to PG enlargement by regulating cellular levels of MepS, a cross-link-specific hydrolase. Here, we demonstrate how NlpI binds Prc to facilitate the degradation of its substrate MepS by structural and mutational analyses...
November 15, 2017: Nature Communications
https://www.readbyqxmd.com/read/29138251/mitochondrial-inner-membrane-protease-yme1-degrades-outer-membrane-proteins-tom22-and-om45
#20
Xi Wu, Lanlan Li, Hui Jiang
Mitochondria are double-membraned organelles playing essential metabolic and signaling functions. The mitochondrial proteome is under surveillance by two proteolysis systems: the ubiquitin-proteasome system degrades mitochondrial outer-membrane (MOM) proteins, and the AAA proteases maintain the proteostasis of intramitochondrial compartments. We previously identified a Doa1-Cdc48(-Ufd1-Npl4) complex that retrogradely translocates ubiquitinated MOM proteins to the cytoplasm for degradation. In this study, we report the unexpected identification of MOM proteins whose degradation requires the Yme1(-Mgr1-Mgr3)i-AAA protease complex in mitochondrial inner membrane...
November 14, 2017: Journal of Cell Biology
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