Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P50583 (asymmetrical)
 12,197 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Singly protonated, doubly protonated, and sodiated pentaglucosamide (GlcNAc)(5), oligoglucosamines (GlcN)(m)(), and (GlcN)(3)GlcN(3OH14:0) were analyzed in an FTICR mass spectrometer by electron-ion dissociation reactions and compared to collision activation. The general fragmentation mode was found as the asymmetrical sequence fragments (B(n)() and minor C(n)() ion series) with full sequence coverage. Molecular mass information of each glucosamide or glucosamine residue can be readily obtained from the ion series. Fragmentation by electron capture dissociation revealed additional fragmentation of the N-acetyl moiety compared to sustained off-resonance irradiation collision-activated dissociation (SORI-CAD) and electron-induced dissociation (EID). Sodiated GlcNAc(5) molecular adduct ions were analyzed by EID and compared to CAD. Both techniques provided full sequence coverage. EID was more effective, but CAD resulted in the cross-ring ion products (0,2)A(n)() and (2,4)A(n)() for all relevant glucosamide residues.
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PMID:Applications of electron-ion dissociation reactions for analysis of polycationic chitooligosaccharides in Fourier transform mass spectrometry. 1458 42

Epidemiological associations are now well-established between insulin resistance, the metabolic syndrome and worsened cardiovascular outcomes. A direct role of insulin in vascular biology is also now broadly recognized. Specifically, insulin can directly stimulate the action of nitric oxide synthase, an effect that can be demonstrated both in vitro and in vivo. Insulin resistance, whether present endogenously or produced experimentally through exposure to fatty acids, glucosamine or tumour necrosis factor alpha, is associated with impaired endothelium-dependent vasodilation and, specifically, with impaired insulin-stimulated vasodilation. A number of potential molecular explanations for these observations are being pursued, with evidence to support a number of concurrent pathogenic mechanisms. These include insulin resistance-associated reductions in nitric oxide availability due to increases in oxidative stress (not requiring the presence of hyperglycemia), reduced availability of tetrahydrobiopterin and excess levels of asymmetrical dimethylarginine. A strong body of evidence also supports an excess of the vasoconstrictor endothelin, which may result directly from hyperinsulinemia and/or indirectly due to a loss of the suppressive effects of nitric oxide on endothelin production and action. The current leading edge of investigations into the association between insulin-resistant states and vascular dysfunction involves the expanding repertoire of adipocyte-derived hormones. Of these, particular interest has been focused on adiponectin, which has both vascular and metabolic actions, and may contribute importantly to the connection between metabolism and vascular function. Progress along these novel lines of investigation will continue to expand the understanding of the mechanisms linking insulin resistance, the metabolic syndrome and vascular disease.
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PMID:Insulin resistance, metabolic syndrome and vascular diseases: update on mechanistic linkages. 1530 8

The composition of samples obtained upon complexation of DNA with chitosan was analyzed by asymmetrical flow field flow fractionation (AF4) with online UV-visible, multiangle light scattering (MALS), and dynamic light scattering (DLS) detectors. A chitosan labeled with rhodamine B to facilitate UV-vis detection of the polycation was complexed with DNA under conditions commonly used for transfection (chitosan glucosamine to DNA phosphate molar ratio of 5). AF4 analysis revealed that 73% of the chitosan-rhodamine remained free in the dispersion and that the DNA/chitosan complexes had a broad size distribution ranging from 20 to 160 nm in hydrodynamic radius. The accuracy of the data was assessed by comparison with data from batch-mode DLS and scanning electron microscopy. The AF4 combined with DLS allowed the characterization of small particles that were not detected by conventional batch-mode DLS. The AF4 analysis will prove to be an important tool in the field of gene therapy because it readily provides, in a single measurement, three important physicochemical parameters of the complexes: the amount of unbound polycation, the hydrodynamic size of the complexes, and their size distribution.
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PMID:One-step analysis of DNA/chitosan complexes by field-flow fractionation reveals particle size and free chitosan content. 2015 94

Similar to most Gram-negative bacteria, the outer leaflet of the outer membrane of Vibrio cholerae is comprised of lipopolysaccharide. Previous reports have proposed that V. cholerae serogroups O1 and O139 synthesize structurally different lipid A domains, which anchor lipopolysaccharide within the outer membrane. In the current study, intact lipid A species of V. cholerae O1 and O139 were analysed by mass spectrometry. We demonstrate that V. cholerae serogroups associated with human disease synthesize a similar asymmetrical hexa-acylated lipid A species, bearing a myristate (C14:0) and 3-hydroxylaurate (3-OH C12:0) at the 2'- and 3'-positions respectively. A previous report from our laboratory characterized the V. cholerae LpxL homologue Vc0213, which transfers a C14:0 to the 2'-position of the glucosamine disaccharide. Our current findings identify V. cholerae Vc0212 as a novel lipid A secondary hydroxy-acyltransferase, termed LpxN, responsible for transferring the 3-hydroxylaurate (3-OH C12:0) to the V. cholerae lipid A domain. Importantly, the presence of a 3-hydroxyl group on the 3'-linked secondary acyl chain was found to promote antimicrobial peptide resistance in V. cholerae; however, this functional group was not required for activation of the innate immune response.
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PMID:Elucidation of a novel Vibrio cholerae lipid A secondary hydroxy-acyltransferase and its role in innate immune recognition. 2175 9