scholarly journals Collagen-Chitosan Hydrogel Formed in Situ Via Enzymatic Crosslinking

2018 ◽  
Vol 7 (4.38) ◽  
pp. 1402
Author(s):  
Lau Sin Mun ◽  
Masrina Mohd Nadzir ◽  
Shiplu Roy Chowdhury ◽  
Mohd Fauzi Mh Busra
Keyword(s):  
Oxidative Coupling ◽  
Cell Attachment ◽  
Biological Properties ◽  
Crosslinking Reaction ◽  
The Novel ◽  
Chitosan Hydrogel ◽  
Physiological Conditions ◽  
Hydrogel Composite ◽  
Injectable Collagen

In this research, injectable collagen-chitosan conjugates (Col-Chit-Ph) hydrogel was formed by oxidative coupling of phenolic hydroxyl (Ph) groups in polymer chain via peroxidase-catalysed crosslinking reaction. The resulting Col-Chit-Ph solutions formed rapid hydrogel at physiological conditions by utilizing H2O2. The amount of chitosan in the compositions of Col-Chit-Ph hydrogels influenced the mechanical properties of the hydrogels. Here, conjugates having Col:Chit ratio of 1:1 showed greater resistance to compression compared to conjugates having Col:Chit ratio of 3:2. Meanwhile, the efficiency of cell attachment for conjugates with Col:Chit ratio of 4:1 is higher than conjugates with Col:Chit ratio of 1:1. Although the biological properties of hydrogel was good at Col:Chit ratio of 4:1, this hydrogel easily destroyed by external force. However, with higher amount of chitosan in the composite, hydrogels were more mechanically stable. This indicates the importance of the chitosan ratio to the novel Col-Chit-Ph injectable hydrogel composite.   

Calpains: a physiological regulator of the endothelial barrier?

2006 ◽  
Vol 290 (5) ◽  
pp. H2035-H2042 ◽  
Author(s):  
Vera Gonscherowski ◽  
Bernhard F. Becker ◽  
Louis Moroder ◽  
Elena Motrescu ◽  
Shirley Gil-Parrado ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Guinea Pig ◽  
Phase Contrast ◽  
Cell Attachment ◽  
Endothelial Barrier ◽  
Calpain Inhibitor ◽  
The Novel ◽  
Physiological Conditions ◽  
Isolated Hearts ◽  
Physiological Regulator

The intracellular protease calpain, abundant in endothelial cells (EC), is assumed to be inactive under physiological conditions but may account for Ca2+-linked pathophysiological events. However, nonstimulated EC contained autolyzed, activated calpain. Adding 12–48 μM calpain inhibitor I (CI) or 0.5–1 μM of the novel, membrane-permeable conjugate of calpastatin peptide-penetratin (CPP) caused rapid rounding and retraction of cultured EC (phase contrast, capacitance) and translocation of Syk, Rac, and Rho to the membrane, signifying activation upon inhibition of calpain. Isolated hearts (guinea pig) perfused with 12 μM CI or 0.5 μM CPP developed coronary leak. We conclude that calpain is constitutively active in EC and regulates vascular permeability by governing cell-cell attachment.

scholarly journals Influence of protein (human galectin-3) design on aspects of lectin activity

2020 ◽  
Vol 154 (2) ◽  
pp. 135-153 ◽  
Author(s):  
Gabriel García Caballero ◽  
Donella Beckwith ◽  
Nadezhda V. Shilova ◽  
Adele Gabba ◽  
Tanja J. Kutzner ◽  
...  
Keyword(s):  
Protein Design ◽  
Full Range ◽  
Biological Information ◽  
The Novel ◽  
Modular Assembly ◽  
Binding Partners ◽  
Galectin 3 ◽  
Potential Applications ◽  
Similar Affinity

Abstract The concept of biomedical significance of the functional pairing between tissue lectins and their glycoconjugate counterreceptors has reached the mainstream of research on the flow of biological information. A major challenge now is to identify the principles of structure–activity relationships that underlie specificity of recognition and the ensuing post-binding processes. Toward this end, we focus on a distinct feature on the side of the lectin, i.e. its architecture to present the carbohydrate recognition domain (CRD). Working with a multifunctional human lectin, i.e. galectin-3, as model, its CRD is used in protein engineering to build variants with different modular assembly. Hereby, it becomes possible to compare activity features of the natural design, i.e. CRD attached to an N-terminal tail, with those of homo- and heterodimers and the tail-free protein. Thermodynamics of binding disaccharides proved full activity of all proteins at very similar affinity. The following glycan array testing revealed maintained preferential contact formation with N-acetyllactosamine oligomers and histo-blood group ABH epitopes irrespective of variant design. The study of carbohydrate-inhibitable binding of the test panel disclosed up to qualitative cell-type-dependent differences in sections of fixed murine epididymis and especially jejunum. By probing topological aspects of binding, the susceptibility to inhibition by a tetravalent glycocluster was markedly different for the wild-type vs the homodimeric variant proteins. The results teach the salient lesson that protein design matters: the type of CRD presentation can have a profound bearing on whether basically suited oligosaccharides, which for example tested positively in an array, will become binding partners in situ. When lectin-glycoconjugate aggregates (lattices) are formed, their structural organization will depend on this parameter. Further testing (ga)lectin variants will thus be instrumental (i) to define the full range of impact of altering protein assembly and (ii) to explain why certain types of design have been favored during the course of evolution, besides opening biomedical perspectives for potential applications of the novel galectin forms.

Improvement in mechanical, physical and biological properties of eucalyptus and pine woods by raw pine resin in situ polymerization

2021 ◽  
Vol 166 ◽  
pp. 113495
Author(s):  
Andrey Pereira Acosta ◽  
Kelvin Techera Barbosa ◽  
Sandro Campos Amico ◽  
André Luiz Missio ◽  
Rafael de Avila Delucis ◽  
...  
Keyword(s):  
In Situ Polymerization ◽  
Biological Properties ◽  
Pine Resin

Ultrasound accelerated near-edge functionalized heterogeneous graphene oxide sonocatalyst for surface optical bandwidth efficacy and in-situ sonothermocatalysis

2021 ◽  
Author(s):  
Gopal Avashthi ◽  
Man Singh
Keyword(s):  
Graphene Oxide ◽  
The Novel ◽  
Surface Optical ◽  
Optical Bandwidth

Ultrasonochemically driven graphene oxide (GrO) functionalization (f) with Sulfanilamide (SA) near-edge catalyzed heterogeneous graphene oxide (h-GrO) as economic scalable f-(SA)GrO is reported. The novel in-situ H2O association was subsequently aligned...

scholarly journals Radiation-initiated high strength chitosan/lithium sulfonate double network hydrogel/aerogel with porosity and stability for efficient CO2 capture

RSC Advances ◽  
2021 ◽  
Vol 11 (33) ◽  
pp. 20486-20497
Author(s):  
Zhiyan Liu ◽  
Rui Ma ◽  
Wenjie Du ◽  
Gang Yang ◽  
Tao Chen
Keyword(s):  
Aqueous Solution ◽  
High Strength ◽  
Beam Radiation ◽  
Chitosan Hydrogel ◽  
Double Network ◽  
Electron Beam Radiation ◽  
Freeze Dried ◽  
Urea Aqueous Solution ◽  
Capture Capacity

Chitosan hydrogel is regenerated from alkali/urea aqueous solution and the lithium sulfonate second network is introduced by electron beam radiation-initiated in situ free radical polymerization. The freeze-dried aerogel has CO2 capture capacity.

scholarly journals One-Pot Synthesis of Novel Multisubstituted 1-Alkoxyindoles

Molecules ◽  
2021 ◽  
Vol 26 (5) ◽  
pp. 1466
Author(s):  
Ye Eun Kim ◽  
Hyunsung Cho ◽  
Yoo Jin Lim ◽  
Chorong Kim ◽  
Sang Hyup Lee
Keyword(s):  
Alkyl Halide ◽  
The Novel ◽  
Reaction Conditions ◽  
One Pot ◽  
One Pot Synthesis ◽  
Consecutive Reactions ◽  
Intramolecular Condensation ◽  
Synthetic Sequence ◽  
Novel Target

Studies on a one-pot synthesis of novel multisubstituted 1-alkoxyindoles 1 and their mechanistic investigations are presented. The synthesis of 1 was successfully achieved through consecutive four step reactions from substrates 2. The substrates 2, prepared through a two-step synthetic sequence, underwent three consecutive reactions of nitro reduction, intramolecular condensation, and nucleophilic 1,5-addition to provide the intermediates, 1-hydroxyindoles 8, which then were alkylated in situ with alkyl halide to afford the novel target products 1. We optimized the reaction conditions for 1 focusing on the alkylation step, along with the consideration of formation of intermediates 8. The optimized condition was SnCl2·2H2O (3.3 eq) and alcohols (R1OH, 2.0 eq) for 1–2 h at 40 °C and then, base (10 eq) and alkyl halides (R2Y, 2.0 eq) for 1–4 h at 25–50 °C. Notably, all four step reactions were performed in one-pot to give 1 in good to modest yields. Furthermore, the mechanistic aspects were also discussed regarding the reaction pathways and the formation of side products. The significance lies in development of efficient one-pot reactions and in generation of new 1-alkoxyindoles.

In situ forming pluronic® F127/chitosan hydrogel limits metronidazole transmucosal absorption

2017 ◽  
Vol 112 ◽  
pp. 143-147 ◽  
Author(s):  
Sophia Malli ◽  
Christian Bories ◽  
Bénédicte Pradines ◽  
Philippe M. Loiseau ◽  
Gilles Ponchel ◽  
...  
Keyword(s):  
Chitosan Hydrogel ◽  
In Situ Forming

scholarly journals Physiological Role for Phosphatidic Acid in the Translocation of the Novel Protein Kinase C Apl II in Aplysia Neurons

2008 ◽  
Vol 28 (15) ◽  
pp. 4719-4733 ◽  
Author(s):  
Carole A. Farah ◽  
Ikue Nagakura ◽  
Daniel Weatherill ◽  
Xiaotang Fan ◽  
Wayne S. Sossin
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Phosphatidic Acid ◽  
Physiological Role ◽  
C2 Domain ◽  
The Novel ◽  
Physiological Conditions ◽  
Kinase C ◽  
Neuronal Membranes ◽  
Novel Protein

ABSTRACT In Aplysia californica, the serotonin-mediated translocation of protein kinase C (PKC) Apl II to neuronal membranes is important for synaptic plasticity. The orthologue of PKC Apl II, PKCε, has been reported to require phosphatidic acid (PA) in conjunction with diacylglycerol (DAG) for translocation. We find that PKC Apl II can be synergistically translocated to membranes by the combination of DAG and PA. We identify a mutation in the C1b domain (arginine 273 to histidine; PKC Apl II-R273H) that removes the effects of exogenous PA. In Aplysia neurons, the inhibition of endogenous PA production by 1-butanol inhibited the physiological translocation of PKC Apl II by serotonin in the cell body and at the synapse but not the translocation of PKC Apl II-R273H. The translocation of PKC Apl II-R273H in the absence of PA was explained by two additional effects of this mutation: (i) the mutation removed C2 domain-mediated inhibition, and (ii) the mutation decreased the concentration of DAG required for PKC Apl II translocation. We present a model in which, under physiological conditions, PA is important to activate the novel PKC Apl II both by synergizing with DAG and removing C2 domain-mediated inhibition.

scholarly journals Insertion of Phosphenium Ions into a Bicyclo[1.1.0]Tetraphosphabutane Iron Complex

Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 3920
Author(s):  
Martin Weber ◽  
Gábor Balázs ◽  
Alexander V. Virovets ◽  
Eugenia Peresypkina ◽  
Manfred Scheer
Keyword(s):  
Diffraction Analysis ◽  
Room Temperature ◽  
31P Nmr ◽  
Spectroscopic Studies ◽  
Iron Complex ◽  
The Novel ◽  
X Ray Diffraction ◽  
X Ray ◽  
Phosphenium Ions

By reacting [{Cp‴Fe(CO)2}2(µ,η1:1-P4)] (1) with in situ generated phosphenium ions [Ph2P][A] ([A]− = [OTf]− = [O3SCF3]−, [PF6]−), a mixture of two main products of the composition [{Cp‴Fe(CO)2}2(µ,η1:1-P5(C6H5)2)][PF6] (2a and 3a) could be identified by extensive 31P NMR spectroscopic studies at 193 K. Compound 3a was also characterized by X-ray diffraction analysis, showing the rarely observed bicyclo[2.1.0]pentaphosphapentane unit. At room temperature, the novel compound [{Cp‴Fe}(µ,η4:1-P5Ph2){Cp‴(CO)2Fe}][PF6] (4) is formed by decarbonylation. Reacting 1 with in situ generated diphenyl arsenium ions gives short-lived intermediates at 193 K which disproportionate at room temperature into tetraphenyldiarsine and [{Cp‴Fe(CO)2}4(µ4,η1:1:1:1-P8)][OTf]2 (5) containing a tetracyclo[3.3.0.02,7.03,6]octaphosphaoctane ligand.

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