Search results for "cop"

Hands On: Using Tryptophan Fluorescence Spectroscopy to Study Protein Structure

2019

Fluorescence spectroscopy is well suited to obtain information about the structure and function of proteins. The major advantage of this spectroscopic technique is the pronounced dependence of the fluorescence emission characteristics of fluorophores on their distinct local environment and the rather inexpensive equipment required. In particular, the use of intrinsic tryptophan fluorescence offers the possibility to study structure and function of proteins without the need to modify the protein. While fluorescence spectroscopy is technically not demanding, a number of factors can artificially alter the results. In this article, we systematically describe the most common applications in fluo…

The effect of photodynamic therapy and polymer solution containing nano-particles of Ag /ZnO on push-out bond strength of the sealers AH-Plus and MTA…

2017

BACKGROUND The aim of this in vitrostudy was to examine and compare the effect of photodynamic therapy and solution containing nano particles Ag/ZnO on adhesion of endodontic sealers to dentinal walls of human root canal. MATERIAL AND METHODS Ninty single-rooted human teeth were selected and their clinical crown was cut from the cemento-enamel junction zone. Canals were prepared by RaCe rotary system and the smear layer was removed using 17% EDTA and 5.25% NaOCl. Samples were randomly divided into two groups of AH Plus and MTA Fillapex based on the sealer type and each group based on antimicrobial method was divided into two sub-groups of photodynamic therapy and polymer containing nano par…

Genomic characterization of a local epidemic Pseudomonas aeruginosa reveals specific features of the widespread clone ST395

2017

International audience; Pseudomonas aeruginosa is a ubiquitous opportunistic pathogen with several clones being frequently associated with outbreaks in hospital settings. ST395 is among these so-called 'international' clones. We aimed here to define the biological features that could have helped the implantation and spread of the clone ST395 in hospital settings. The complete genome of a multidrug resistant index isolate (DHS01) of a large hospital outbreak was analysed. We identified DHS01-specific genetic elements, among which were identified those shared with a panel of six independent ST395 isolates responsible for outbreaks in other hospitals. DHS01 has the fifth largest chromosome of …

Mineral analysis of human diets by spectrometry methods

2016

Abstract Mineral element determination in human diets is very important for human health, due to the presence in foods of essential and toxic elements or their incorporation in the manipulation and cooking food process. Different instrumental techniques have been used to determine mineral elements in human diets, but atomic spectroscopy and mass spectrometry based ones are the most commonly employed. Sampling procedures for diet analysis are the main critically step for mineral element determination, being employed different standardised protocols. This review summarised critically the state-of-the-art of mineral analysis in human diets, considering sampling, sample preparation and determin…

2021

Lipids contained in the plasma membrane of platelets play an important role in platelet function. Modifications in the lipid composition can fluidify or rigidify the environment around embedded receptors, in order to facilitate the access of the receptor by the drug. However, data concerning the lipid composition of platelet plasma membrane need to be updated. In addition, data on the impact of drugs on plasma membrane composition, in particular antiplatelet agents, remain sparse. After isolation of platelet plasma membrane, we assessed, using lipidomics, the effect of ticagrelor, a P2Y12 antagonist, and its active metabolite on the lipid composition of these plasma membranes. We describe t…

Bifunctional poly(acrylamide) hydrogels through orthogonal coupling chemistries

2019

Biomaterials for cell culture allowing simple and quantitative presentation of instructive cues enable rationalization of the interplay between cells and their surrounding microenvironment. Poly(acrylamide) (PAAm) hydrogels are popular 2D-model substrates for this purpose. However, quantitative and reproducible biofunctionalization of PAAm hydrogels with multiple ligands in a trustable, controlled, and independent fashion is not trivial. Here, we describe a method for bifunctional modification of PAAm hydrogels with thiol- and amine- containing biomolecules with controlled densities in an independent, orthogonal manner. We developed copolymer networks of AAm with 9% acrylic acid and 2% N-(4…

Mechanics Insights of Alpha-Lipoic Acid against Cardiovascular Diseases during COVID-19 Infection

2021

Coronavirus disease 2019 (COVID-19) was first reported in Wuhan, China, in late December 2019. Since then, COVID-19 has spread rapidly worldwide and was declared a global pandemic on 20 March 2020. Cardiovascular complications are rapidly emerging as a major peril in COVID-19 in addition to respiratory disease. The mechanisms underlying the excessive effect of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection on patients with cardiovascular comorbidities remain only partly understood. SARS-CoV-2 infection is caused by binding of the viral surface spike (S) protein to the human angiotensin-converting enzyme 2 (ACE2), followed by the activation of the S protein by transme…

Epimagnolin A, a tetrahydrofurofuranoid lignan from Magnolia fargesii, reverses ABCB1-mediated drug resistance.

2018

Abstract Background Epimagnolin A is an ingredient of the Chinese crude drug Shin-i, derived from the dried flower buds of Magnolia fargesii and Magnolia flos, which has been traditionally used for the treatment of allergic rhinitis and nasal congestion, empyema, and sinusitis. The pharmacokinetic activity of epimagnolin A remains to be evaluated. Purpose In this study, we examined the possible interactions of epimagnolin A with human ATP-binding cassette (ABC) transporter ABCB1, a membrane protein vital in regulating the pharmacokinetics of drugs and xenobiotics. Study design/methods The interaction of epimagnolin A with ABCB1 was evaluated in calcein, ATPase, and MTT assays by using Flp-I…

Simultaneous Determination of Caffeine and Chlorogenic Acids in Green Coffee by UV/Vis Spectroscopy

2017

A simple method for the simultaneous determination of caffeine and chlorogenic acids content in green coffee was reported. The method was based on the use of UV/Vis absorption. It is relevant that the quantification of both caffeine and chlorogenic acids was performed without their preliminary chemical separation despite their spectral overlap in the range 250–350 nm. Green coffee was extracted with 70% ethanol aqueous solution; then the solution was analyzed by spectroscopy. Quantitative determination was obtained analytically through deconvolution of the absorption spectrum and by applying the Lambert-Beer law. The bands used for the deconvolution were the absorption bands of both caffein…

Evaluation of an amino acid residue critical for the specificity and activity of human Gb3/CD77 synthase

2016

Human Gb3/CD77 synthase (α1,4-galactosyltransferase) is the only known glycosyltransferase that changes acceptor specificity because of a point mutation. The enzyme, encoded by A4GALT locus, is responsible for biosynthesis of Gal(α1–4)Gal moiety in Gb3 (CD77, Pk antigen) and P1 glycosphingolipids. We showed before that a single nucleotide substitution c.631C > G in the open reading frame of A4GALT, resulting in replacement of glutamine with glutamic acid at position 211 (substitution p. Q211E), broadens the enzyme acceptor specificity, so it can not only attach galactose to another galactose but also to N-acetylgalactosamine. The latter reaction leads to synthesis of NOR antigens, which are…