Search results for "Amy"
showing 10 items of 1486 documents
Reply to Dr Michaudet al.
2015
There is no abstract
Determination of macrolide and lincosamide antibiotics by pressurised liquid extraction and liquid chromatography-tandem mass spectrometry in meat an…
2010
Abstract A total of 155 samples, including meat and milk, were analyzed using a method developed for determining five macrolide antibiotics: tilmicosin (TILM), tylosin (TS), spiramycin (SPM), erythromycin (ERY), and tulathromycin (TULA) and two lincosamide antibiotics: pirlimycin (PIRL) and lincomycin (LM). The method was performed by pressurised liquid extraction (PLE) coupled to LC–MS/MS using electrospray ionization in positive ion mode. 2.5 mL of milk or 2.5 g of meat were dispersed in ethylenediaminetetraacetic acid sodium salt 2-hydrate (EDTA) and sea sand. The PLE conditions as: solvent, temperature, pressure, static time, and cell size were optimized. The following analytical parame…
Influence of the food matrix structure on the retention of aroma compounds.
2000
The retention of the aroma compounds in a multicomponent medium like the food matrix is influenced by their affinity with the protein when lipid is present at a low level (0.5%). The effect of the structure of the media is also studied by using two media with the same composition; one was emusified, and the other was not. Among the studied aroma compounds, 2-nonanone and isoamyl acetate present opposite behaviors: the volatility of isoamyl acetate is not affected by the change of the medium structure whereas that of 2-nonanone increases. The decrease of retention of 2-nonanone in an emulsified system would be due to a modification of the fixation site for this compound on the protein or to …
Influence of the Liquefied Starch Composition and pH on the Saccharification at the Obtaining of Maltose Syrup
1970
In this paper the influence of the composition of the liquefied starch and of pH on the quality of saccharification at the obtaining of maltose syrup is investigated. A large number of experiments (68) in various liquefaction conditions show that Dextrose Equivalent (DE) and the composition in hydrolysis products with Degree of Polymerisation higher as four (DP ≥4) in the liquefied starch have a strong influence on the saccharification products, mainly on the maltose content in the maltose syrups. The liquefied starch with DE lower as 25 has smaller amounts of DP ≥4 (40 to 60%), whereas the liquefied starch with DE between 25 and 27 has high amounts of DP ≥4 (60 to 80%). For the production …
Modelling of Starch Gelatinisation and Liquefaction with the Enzyme Liquozyme
2011
In this paper the influence of the enzyme Liquozyme Supra concentration (0.4-1.2 kg/t dry substance DS) and gelatinisation time (3-11 min.) on the liquefied starch quality is investigated. The composition in sugars with different Degrees of Polymerisation (DP) as DP1 (glucose), DP2 (maltose), DP3 (maltotriose), DP4 (maltotetrose) and oligosaccharides with DP≥5 is analysed by using HPLC with RI detector. The products obtained have different DP, the main components being oligosaccharides with DP≥5, followed by small amount of DP3+DP4 and much smaller concentrations of DP1; no DP2 is produced by this enzyme. Two quality criteria: the percent of oligosaccharides with DP≥5 and the percent of DP1…
Two heterologously expressed Planobispora rosea proteins cooperatively induce Streptomyces lividans thiostrepton uptake and storage from the extracel…
2010
Abstract Background A bacterial artificial chromosomal library of Planobispora rosea, a genetically intractable actinomycete strain, was constructed using Escherichia coli-Streptomyces artificial chromosome (ESAC) and screened for the presence of genes known to be involved in the biosynthesis of antibiotics. Results One clone with a 40 kb insert showed antimicrobial activity against Gram positive bacteria. Insert sequence analysis and subcloning experiments revealed that the bioactivity was due to a 3.5 kb DNA fragment containing two open reading frames. These orfs encode two proteins with high similarity to a putative membrane protein of Streptomyces coelicolor and to the nogalamycin resis…
Diurnal variation of corticotropin-releasing factor binding sites in the rat brain and pituitary.
1996
1. Corticotropin-releasing factor (CRF) is thought to be involved in the regulation of the diurnal activity of the hypothalamus-pituitary-adrenal (HPA) axis and to act as a neurotransmitter in the brain. To date it is unknown whether the binding sites of the central CRF system are subject to diurnal variations. 2. We measured the number of CRF binding sites over the course of a complete 24-hr light-dark cycle in the pituitary, amygdala, bed nucleus of the stria terminalis (BNST), cingulate cortex, visceral cortex, paraventricular nucleus of the hypothalamus, hippocampus, and locus ceruleus of rats by in vitro receptor autoradiography with iodinated ovine CRF. A 24-hr time course was also es…
Entrapment of A Beta 1-40 peptide in unstructured aggregates
2012
Recognizing the complexity of the fibrillogenesis process provides a solid ground for the development of therapeutic strategies aimed at preventing or inhibiting protein-protein aggregation. Under this perspective, it is meaningful to identify the possible aggregation pathways and their relative products. We found that Aβ-peptide dissolved in a pH 7.4 solution at small peptide concentration and low ionic strength forms globular aggregates without typical amyloid β-conformation. ThT binding kinetics was used to monitor aggregate formation. Circular dichroism spectroscopy, AFM imaging, static and dynamic light scattering were used for structural and morphological characterization of the aggre…
Amyloid fibrils formation and amorphous aggregation in Concanavalin A
2007
We here report an experimental study on the thermal aggregation process of concanavalin A, a protein belonging to the legume lectins family. The aggregation process and the involved conformational changes of the protein molecules were followed by means of fluorescence techniques, light scattering, circular dichroism, zeta potential measurements and atomic force microscopy. Our results show that the aggregation process of concanavalin A may evolve through two distinct pathways leading, respectively, to the formation of amyloids or amorphous aggregates. The relative extent of the two pathways is determined by pH, as amyloid aggregation is favored at high pH values ( approximately 9), while th…
Irreversible formation of intermediate BSA oligomers requires and induces conformational changes.
2004
Understanding the relation between protein conformational changes and aggregation, and the physical mechanisms leading to such processes, is of primary importance, due to its direct relation to a vast class of severe pathologies. Growing evidence also suggests that oligomeric intermediates, which may occur early in the aggregation pathway, can be themselves pathogenic. The possible cytotoxicity of oligomers of non-disease-associated proteins adds generality to such suggestion and to the interest of studies of oligomer formation. Here we study the early stages of aggregation of Bovine Serum Albumin (BSA), a non pathogenic protein which has proved to be a useful model system. Dynamic light sc…