Search results for "acids"
showing 10 items of 3520 documents
Mobilization of late-endosomal cholesterol is inhibited by Rab guanine nucleotide dissociation inhibitor
2000
AbstractCholesterol entering cells in low-density lipoproteins (LDL) via receptor-mediated endocytosis is transported to organelles of the late endocytic pathway for degradation of the lipoprotein particles. The fate of the free cholesterol released remains poorly understood, however. Recent observations suggest that late-endosomal cholesterol sequestration is regulated by the dynamics of lysobisphosphatidic acid (LBPA)-rich membranes [1]. Genetic studies have pinpointed a protein, Niemann–Pick C-1 (NPC-1), that is required for the mobilization of late-endosomal/lysosomal cholesterol by an unknown mechanism [2]. Here, we report the removal of accumulated cholesterol by overexpression of the…
The Emerging Role of the Endocannabinoid System in Endocrine Regulation and Energy Balance
2005
During the last few years, the endocannabinoid system has emerged as a highly relevant topic in the scientific community. Many different regulatory actions have been attributed to endocannabinoids, and their involvement in several pathophysiological conditions is under intense scrutiny. Cannabinoid receptors, named CB1 receptor and CB2 receptor, first discovered as the molecular targets of the psychotropic component of the plant Cannabis sativa, participate in the physiological modulation of many central and peripheral functions. CB2 receptor is mainly expressed in immune cells, whereas CB1 receptor is the most abundant G protein-coupled receptor expressed in the brain. CB1 receptor is expr…
Approaches to find complementary separation conditions for resolving complex mixtures by high-performance liquid chromatography
2012
Chromatographic problems are usually addressed trying to find out a single experimental condition aimed to resolve all compounds in the sample. However, very often, the chromatographic system is not able to provide full resolution. When a separation fails, the usual choice is introducing a drastic change in the chromatographic system (e.g. column, solvent, pH). There are, however, other possibilities that take advantage of the gathered information in the failed separation, without the need of new experiments, based on the concept of complementary separations (e.g. isocratic mobile phases, gradients, columns, chromatographic modes). One separation condition will focus on the resolution of so…
Influence of ligand density on the properties of metal-chelate affinity supports.
1993
A new procedure has been developed to immobilize iminodiacetic acid (IDA) onto the surface of silica supports, such as LiChrospher Si-1000 and 1.5-microns nonporous silica, for use in high-performance immobilized metal affinity chromatography (HPIMAC) of proteins. This IDA immobilization method has been achieved through the synthesis of a new silylation reagent, 1-(iminodiacetic acid di-tert-butylester)-3-glycidoxy-propyltrimethoxysilane (IDA-silane). Various modified silicas of different ligand densities have been prepared by using mixtures between 1 and 100% of the IDA-silane diluted with the corresponding 3-glycidoxy-propyltrimethoxysilane (GLYMO-silane). Frontal analysis was used with t…
Effects of Dietary Supplementation with Honeybee Pollen and Its Supercritical Fluid Extract on Immune Response and Fillet’s Quality of Farmed G…
2022
The awareness of the correlation between administered diet, fish health and products’ quality has led to the increase in the research for innovative and functional feed ingredients. Herein, a plant-derived product rich in bioactive compounds, such as honeybee pollen (HBP), was included as raw (HBP) and as Supercritical Fluid Extracted (SFE) pollen (HBP_SFE) in the diet for gilthead seabream (Sparus aurata). The experiment was carried out on 90 fish with an average body weight of 294.7 ± 12.8 g, divided into five groups, according to the administration of five diets for 30 days: control diet (CTR); two diets containing HBP at 5% (P5) and at 10% (P10) level of inclusion; two diet…
Specific tyrosine phosphorylation in response to bile in Fasciola hepatica and Echinostoma friedi
2003
Protein tyrosine phosphorylation (PY) is a well-known signalling mechanism which is also involved in host-parasite interactions. Despite its transcendence, PY has been poorly studied in parasitic helminths. The aim of this study is to examine the effect of bile salts on the PY pattern in parasitic trematodes. Two distinct adult models were analysed: Echinostoma friedi, of intestinal habitat, and Fasciola hepatica, naturally inhabitant of host biliary channels. Our results show that bile salts induce specific and distinct protein PY in both trematode species, indicating that this signalling process seems to be also involved in host-trematode relationships.
Low Density Lipoprotein Receptor-related Protein (LRP) Interacts with Presenilin 1 and Is a Competitive Substrate of the Amyloid Precursor Protein (A…
2005
Presenilin 1 (PS1) is a critical component of the gamma-secretase complex, which is involved in the cleavage of several substrates including the amyloid precursor protein (APP) and the Notch receptor. Recently, the low density receptor-related protein (LRP) has been shown to be cleaved by a gamma-secretase-like activity. We postulated that LRP may interact with PS1 and tested its role as a competitive substrate for gamma-secretase. In this report we show that LRP colocalizes and interacts with endogenous PS1 using coimmunoprecipitation and fluorescence lifetime imaging microscopy. In addition, we found that gamma-secretase active site inhibitors do not disrupt the interaction between LRP an…
A Protein-Interaction Array Inside a Living Cell
2013
Cell phenotype is determined by protein network states that are maintained by the dynamics of multiple protein interactions.1 Fluorescence microscopy approaches that measure protein interactions in individual cells, such as by Forster resonant energy transfer (FRET), are limited by the spectral separation of fluorophores and thus are most suitable to analyze a single protein interaction in a given cell. However, analysis of correlations between multiple protein interactions is required to uncover the interdependence of protein reactions in dynamic signal networks. Available protein-array technologies enable the parallel analysis of interacting proteins from cell extracts, however, they can …
Fluorescence labelling of organic acidic compounds with 4-bromomethyl-7-methoxycoumarin (Br-Mmc)
1977
4-Bromomethyl-7-methoxycoumarin (Br-Mmc) is introduced as a fluorescence marker for aromatic and heterocyclic acids. To investigate the applicability of this method on substances of different chemical classes, screening experiments with 110 compounds were carried out using a microrefluxer. Most aromatic and heterocyclic monocarboxylic acids gave Mmc-esters which are fluorescent on thin-layer plates, like the Mmc-esters of fatty acids, which have been previously investigated. Strong acids, alcohols, amides and most amines did not react, whereas certain cyclic amines such as piperidine gave strongly fluorescent derivatives. Mmc-phenyl ethers shows only weak fluorescence. A new standard proced…
Affinity scale between a carrier and a drug in DPI studied by atomic force microscopy.
2002
The dry powder inhalers (DPIs) consist, in the most cases, of ordered mixture where the particles adhesion results of interactions between the drug and the carrier. Generally, one step of production process is the micronization of the drug particles in order to reduce the size for ordered mixing optimization. But this operation is known to partially create an amorphous surface. In this case, surrounding storage conditions, like relative humidity (RH), are able to modify the percentage of amorphous drug surface. The aim of this study was to investigate surface reactivity, surface energy and direct force measurements by atomic force microscopy (AFM) between lactose (carrier) and zanamivir (dr…