Search results for "muramidase"
showing 10 items of 45 documents
Effects of photodynamic processes and ultraviolet light on duck and hen egg-white lysozymes.
1973
— The photochemical yields for inactivation and amino acid destruction in hen and duck egg-white lysozyme are presented. Duck lysozyme II is devoid of histidine but it has two more tyrosine residues than does hen lysozyme. The data indicate that sensitized oxidation of the single histidine residue of hen lysozyme is of no significance for the inactivation of this lysozyme. The ultraviolet destruction of tryptophan and cystine residues appears to be equally related with the loss in enzymatic activity of hen lysozyme. In the case of duck lysozyme, however, the ultraviolet inactivation appears to be predominantly governed by the destruction of cystine residues.
Integrating genome-wide genetic variations and monocyte expression data reveals trans-regulated gene modules in humans.
2011
One major expectation from the transcriptome in humans is to characterize the biological basis of associations identified by genome-wide association studies. So far, few cis expression quantitative trait loci (eQTLs) have been reliably related to disease susceptibility. Trans-regulating mechanisms may play a more prominent role in disease susceptibility. We analyzed 12,808 genes detected in at least 5% of circulating monocyte samples from a population-based sample of 1,490 European unrelated subjects. We applied a method of extraction of expression patterns—independent component analysis—to identify sets of co-regulated genes. These patterns were then related to 675,350 SNPs to identify maj…
The role of juvenile hormone in immune function and pheromone production trade-offs: a test of the immunocompetence handicap principle
2003
The immunocompetence handicap hypothesis postulates that secondary sexual traits are honest signals of mate quality because the hormones (e.g. testosterone) needed to develop secondary sexual traits have immunosuppressive effects. The best support for predictions arising from the immunocompetence handicap hypothesis so far comes from studies of insects, although they lack male-specific hormones such as testosterone. In our previous studies, we found that female mealworm beetles prefer pheromones of immunocompetent males. Here, we tested how juvenile hormone (JH) affects male investment in secondary sexual characteristics and immune functions in the mealworm beetle, Tenebrio molitor. We inje…
Crystalloid Lysozyme Inclusions in Paneth Cells of Vitamin A-Deficient Rats
1992
The effect of vitamin A-deficiency on jejunal Paneth cells in rats was investigated. Crystalloid particles were observed in secretion granules of Paneth cells from 6 out of 8 rats with vitamin A-deficiency. The particles were similar to those found in Paneth cells under other experimental conditions. Using an immuno-electron-microscopic technique we demonstrated a clear lysozyme immunoreactivity of these particles. In 2 vitamin A-deficient rats tubular structures have been detected in addition to the crystalloid particles. Crystalloid particles or tubular structures were not detectable in a control group of 8 vitamin A-supplemented rats. The morphological alterations of Paneth cells may be …
A muramidase from Acremonium alcalophilum hydrolyse peptidoglycan found in the gastrointestinal tract of broiler chickens
2021
Abstract This study evaluates peptidoglycan hydrolysis by a microbial muramidase from the fungus Acremonium alcalophilum in vitro and in the gastrointestinal tract of broiler chickens. Peptidoglycan used for in vitro studies was derived from 5 gram-positive chicken gut isolate type strains. In vitro peptidoglycan hydrolysis was studied by three approaches: (a) helium ion microscopy to identify visual phenotypes of hydrolysis, (b) reducing end assay to quantify solubilization of peptidoglycan fragments, and (c) mass spectroscopy to estimate relative abundances of soluble substrates and reaction products. Visual effects of peptidoglycan hydrolysis could be observed by helium ion microscopy an…
In vitrouptake of lysozyme-loaded liposomes coated with chitosan biopolymer as model immunoadjuvants
2009
Chitosan binds to negatively charged soy lecithin liposomes by an electrostatic interaction driven by its cationic amino group. This interaction allows developing stable coated vesicles suitable as a targeted carrier and controlled release system for drugs and vaccines. In this work, we studied the effect of chitosan-coated liposomes on the uptake and antigen presentation of hen egg-white lysozyme (HEL) in Peyer's patches peritoneal macrophages isolated from mice. Chitosan-coated liposomes were characterized according to size, zeta potential, and antigen-loading and release properties. Results showed an increase in the positive net charge and size of the liposomes as the concentration of ch…
Multifunctional clickable and protein-repellent magnetic silica nanoparticles
2016
Silica nanoparticles are versatile materials whose physicochemical surface properties can be precisely adjusted. Because it is possible to combine several functionalities in a single carrier, silica-based materials are excellent candidates for biomedical applications. However, the functionality of the nanoparticles can get lost upon exposure to biological media due to uncontrolled biomolecule adsorption. Therefore, it is important to develop strategies that reduce non-specific protein-particle interactions without losing the introduced surface functionality. Herein, organosilane chemistry is employed to produce magnetic silica nanoparticles bearing differing amounts of amino and alkene func…
Irreversible gelation of thermally unfolded proteins:structural and mechanical properties of lysozyme aggregates
2010
The formation of protein aggregates is important in many fields of life science and technology. The morphological and mechanical properties of protein solutions depend upon the molecular conformation and thermodynamic and environmental conditions. Non-native or unfolded proteins may be kinetically trapped into irreversible aggregates and undergo precipitation or gelation. Here, we study the thermal aggregation of lysozyme in neutral solutions. We characterise the irreversible unfolding of lysozyme by differential scanning calorimetry. The structural properties of aggregates and their mechanisms of formation with the eventual gelation are studied at high temperature by spectroscopic, rheolog…
Calculation of partition coefficient and hydrophobic moment of the secondary structure of lysozyme
2001
A method that permits a semiquantitative estimate of the partitioning of any solute between any two media is presented. As an example, the partition coefficients and hydrophobic moment of the secondary structure of lysozyme are calculated. Program GSCAP is written as a version of Pascal's solvent-dependent conformational analysis (SCAP) program. The dipole moments calculated for the helices are trebled with respect to that for the sheet. For helices, the main contribution to the water-accessible surface area is the hydrophobic term, while the hydrophilic part dominates in the sheet. Molecular globularity and the three studied partition coefficients differentiate between helices and sheet.
Influence of anti-inflammatory flavonoids on degranulation and arachidonic acid release in rat neutrophils.
1994
We assessed the effects of 24 flavonoid derivatives, reported as anti-inflammatory, on lysosomal enzyme secretion and arachidonic acid release in rat neutrophils. Amentoflavone, quercetagetin- 7-O -glucoside, apigenin, fisetin, kaem pferol, luteolin and quercetin were the most potent inhibitors of β-glucuronidase and lysozyme release. The first com pound was also able to inhibit basal release. These flavonoids besides chrysin and to a reduced extent, naringenin, significantly inhibited arachidonic acid release from membranes. A correlation between degranulation and arachidonic acid release was found for this series of compounds. Structureactivity relationships and implications for the anti-…