Search results for "MACROMOLECULAR"
showing 10 items of 944 documents
Tailored electrospun nanofibrous polycaprolactone/gelatin scaffolds into an acid hydrolytic solvent system
2018
[EN] Blended nanofibrous scaffolds based on polycaprolactone (PCL) and gelatin (Ge) were successfully prepared. A formic/acetic acid (1:1) mixture was used to dissolve PCL/Ge blends from 100/0 to 20/80 %wt in steps of 10 %wt. The hydrolysis of the PCL diluted in the formic/acetic acid mixture was considered as a method for tailoring the surface morphology and physicochemical features of the nanofibrous PCL/Ge scaffolds as a function of the dissolution time. The fibre diameter remained in the nanoscale range for all the studied scaffolds, which is crucial to mimic the extra-cellular matrix size. The reduction of the intrinsic viscosity, molar mass and hydrodynamic radius found for the PCL mo…
Maltose-conjugated chitosans induce macroscopic gelation of pectin solutions at neutral pH
2014
Injectable polymer scaffolds are particularly attractive for guided tissue growth and drug/cell delivery with minimally invasive intervention. In the present work, "all-polymeric" gelling systems based on pectins and water-soluble maltose-conjugated chitosans (CM) have been developed. Maltose-conjugated chitosan has been synthesized at three different molar ratios, as evaluated by FITR analysis and fluorimetric titration. A thorough rheological characterization of the blends and their parent solutions has been performed. Macroscopic gelation has been achieved by mixing the high esterification degree pectins with CM at higher maltose grafted to chitosan contents. Gels form in a few minutes a…
Development of antibiotic loaded biodegradable matrices to prevent superficial infections associated to total knee arthroplasty.
2019
Abstract Development of a pharmaceutical form for the superficial infections related with arthroplasties would be helpful for clinical practice. In this context, we set out to evaluate ciprofloxacin and gentamicin elution from systems based on chitosan. Films and semisolid hydrogels containing chitosan alone (2%) or in combination with gelatin (6%) or different proportions (from 12% to 36%) of tetrakis-(hydroxymethyl)-phosphonium-chloride (THPC) were tested as delivery systems. Different antibiotic doses were assayed (0.5 mg/cm2,1 mg/cm2 and 2 mg/cm2). Antibiotic release was studied for each formulation. In vitro cytocompatibility studies and a simulation exercise for bioactivity evaluation…
Additional file 1 of Integrative taxonomy resolves species identities within the Macrobiotus pallarii complex (Eutardigrada: Macrobiotidae)
2021
Additional file 1: SM.01. Saturation plots for COI and ITS markers.
Stability and disassembly properties of human naïve Hsp60 and bacterial GroEL chaperonins.
2015
Human Hsp60 chaperonin and its bacterial homolog GroEL, in association with the corresponding co-chaperonins Hsp10 and GroES, constitute important chaperone systems promoting the proper folding of several mitochondrial proteins. Hsp60 is also currently described as a ubiquitous molecule with multiple roles both in health conditions and in several diseases. Naïve Hsp60 bearing the mitochondrial import signal has been recently demonstrated to present different oligomeric organizations with respect to GroEL, suggesting new possible physiological functions. Here we present a combined investigation with circular dichroism and small-angle X-ray scattering of structure, self-organization, and sta…
Host-Guest Interactions of Sodiumsulfonatomethyleneresorcinarene and Quaternary Ammonium Halides : An Experimental-Computational Analysis of the Gues…
2020
The molecular recognition of nine quaternary alkyl- and aryl-ammonium halides (Bn) by two different receptors, Calkyl-tetrasodiumsulfonatomethyleneresorcinarene (An), were studied in solution using 1H NMR spectroscopy. Substitution of methylenesulfonate groups at 2-positions of resorcinol units resulted in an increase of cavity depth by ∼2.80 Å and a narrow cavity aperture compared to Calkyl-2-H-resorcinarenes. The effect of alkyl chain lengths on the endo-complexation, that is the ability to incorporate other than N-methyl chains inside the cavities, were investigated using ammonium cations of the type ⁺NH2(R1)(R2), (R1 = Me, Et, Bu, R2 = Bu, Ph, Bz ). The C−H⋯ interactions between guests …
Properties and significance of apoFNR as a second form of air-inactivated [4Fe-4S]·FNR of Escherichia coli
2005
The active form of the oxygen sensor fumarate nitrate reductase regulator (FNR) of Escherichia coli contains a [4Fe-4S] cluster which is converted to a [2Fe-2S] cluster after reaction with air, resulting in inactivation of FNR. Reaction of reconstituted [4Fe-4S].FNR with air resulted within 5 min in conversion to apoFNR. The rate was comparable to the rate known for [4Fe-4S].FNR/[2Fe-2S].FNR cluster conversion, suggesting that apoFNR is a product of [2Fe-2S].FNR decomposition and a final form of air-inactivated FNR in vitro. Formation of apoFNR and the redox state of the cysteinyl residues were determined in vitro by alkylation. FNR contains five cysteinyl residues, four of which (Cys20, Cy…
Incorporation of dynamic boronate links and Ag nanoparticles into PVA hydrogels for pH-Regulated and prolonged release of methotrexate
2021
Abstract In this study, pH-responsive hydrogels based on PVA-boronate crosslinks were prepared via a simple route and used for controlled and targeted delivery of anticancer drug methotrexate. A double network (DN) hydrogel composed of didiol-boronate/PVA complex as the first network and PVA crystallites generated by a freeze-thaw process as the second one was developed. The swelling of PVA-boronate DN hydrogels demonstrated high sensitivity to multiple stimuli including the pH, temperature, and ionic strength of the media thanks to the dynamic boronate links in the first network. Moreover, unlike previously reported hydrogels based on the boronate linkages, the new DN hydrogels preserved t…
The fnr Gene of Bacillus licheniformis and the Cysteine Ligands of the C-Terminal FeS Cluster
1998
Many of the O2-responsive gene regulators of bacteria are members of the fumarate nitrate reductase-cyclic AMP receptor protein family of transcriptional regulators (12, 13, 15, 17) with predicted structures similar to those of the cyclic AMP receptor protein (11). The Fnr (stands for fumarate nitrate reductase regulator) protein from Escherichia coli (FnrEc) controls the expression of a variety of genes, mainly of anaerobic respiration and metabolism (5, 13). It contains a N-terminal cluster of three essential cysteine residues which are supposed to bind together with Cys122 a [4Fe 4S]2+ cluster which is required for O2 sensing (4, 7, 8, 10, 16). A wide variety of gram-negative bacteria co…
The Myristoylated Alanine-Rich C-Kinase Substrate (MARCKS) is Sequentially Phosphorylated by Conventional, Novel and Atypical Isotypes of Protein Kin…
1995
The myristoylated alanine-rich C-kinase substrate (MARCKS) is the major protein kinase C (PKC) substrate in many cell types including fibroblasts and brain cells. Here we describe the phosphorylation of MARCKS and the site specificity for different PKC isotypes. Conventional (c)PKC beta 1, novel (n)PKC delta and nPKC epsilon efficiently phosphorylated the MARCKS protein in vitro. The Km values were extremely low, reflecting a high affinity between kinases and substrate. The apparent affinity of nPKC delta (Km = 0.06 microM) was higher than that of nPKC epsilon and cPKC beta 1 (Km = 0.32 microM). The rate of substrate phosphorylation was inversely correlated with affinity and decreased in th…