10 research outputs found
Lipase-Catalyzed Acetylation and Esterification of Bile Acids
In this chapter we describe the application of lipases as catalysts in reactions on a relevant family of steroids: the bile acids. Twenty three mono-, diacetyl and ester derivatives of deoxycholic-, chenodeoxycholic-, lithocholic- and cholic acid, fifteen of them new compounds, were obtained through lipase-catalyzed acetylation, esterification and alcoholysis reactions in very good to excellent yield and a highly regioselective way. Among them, acetylated ester products, in which the lipase catalyzed both reactions in one-pot, were obtained. The influence of various reaction parameters in the enzymatic reactions, such as enzyme source, nucleophile/substrate ratio, enzyme/substrate ratio, solvent and temperature, was studied. Some of the reported products are novel and it is not possible to obtain them satisfactorily by following traditional synthetic procedures. Due to its singular structure containing three hydroxyl groups, cholic acid showed a different behavior in the enzymatic reactions, from that observed for the other three bile acids studied. In order to shed light to different behavior of bile acids in the enzymatic reactions, molecular modeling was applied to substrates and some derivatives.Fil: Baldessari, Alicia. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Ciudad Universitaria. Unidad de MicroanĂĄlisis y MĂ©todos FĂsicos en QuĂmica OrgĂĄnica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Unidad de MicroanĂĄlisis y MĂ©todos FĂsicos en QuĂmica OrgĂĄnica; ArgentinaFil: Garcia Liñares, Guadalupe Eugenia. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Ciudad Universitaria. Unidad de MicroanĂĄlisis y MĂ©todos FĂsicos en QuĂmica OrgĂĄnica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Unidad de MicroanĂĄlisis y MĂ©todos FĂsicos en QuĂmica OrgĂĄnica; Argentin
Chemoenzymatic Synthesis of Nitrogen Polymers with Biomedical Applications Catalyzed by Lipases
The application of Candida antarctica lipase B as catalyst in the synthesis of two examples of nitrogen polymers is described. Firstly, we report anovel linear polyamidoamine oligomer, obtained by polymerization of ethyl acrylate and N-methyl-1,3-diaminopropane, catalyzed by Candida antarctica lipase B immobilized on polypropylene. The second part of the chapter describes an efficient route for the synthesis of a novel ÎČ-peptoid oligomer with hydroxyalkyl pendant groups in the nitrogen atom, through the polymerization of ethyl N-(2-hydroxyethyl)-ÎČ-alaninate catalyzed by Candida antarctica lipase B physically adsorbed within a macroporous poly(methyl methacrylate-co-butyl methacrylate) resin.Moreover,two derivatives of the ÎČ-peptoid oligomer were prepared: by acetylation and by grafting polycaprolactone. This last process was performed through ring opening polymerization of caprolactone from the ÎČ-peptoid pendant hydroxyl groups and afforded a brush copolymer. The products were blended with polycaprolactone to make films by solvent casting. The inclusion of the acyl derivatives of the ÎČ-peptoid to polycaprolactone affected the morphology of the film yielding micro- and nanostructured patterns.The obtained products showed biomedical applications.Fil: Baldessari, Alicia. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Ciudad Universitaria. Unidad de MicroanĂĄlisis y MĂ©todos FĂsicos en QuĂmica OrgĂĄnica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Unidad de MicroanĂĄlisis y MĂ©todos FĂsicos en QuĂmica OrgĂĄnica; ArgentinaFil: Garcia Liñares, Guadalupe Eugenia. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Ciudad Universitaria. Unidad de MicroanĂĄlisis y MĂ©todos FĂsicos en QuĂmica OrgĂĄnica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Unidad de MicroanĂĄlisis y MĂ©todos FĂsicos en QuĂmica OrgĂĄnica; Argentin
Functional crosstalk of PGC-1 coactivators and inflammation in skeletal muscle pathophysiology
Skeletal muscle is an organ involved in whole body movement and energy metabolism with the ability to dynamically adapt to different states of (dis-)use. At a molecular level, the peroxisome proliferator-activated receptor Îł coactivators 1 (PGC-1s) are important mediators of oxidative metabolism in skeletal muscle and in other organs. Musculoskeletal disorders as well as obesity and its sequelae are associated with PGC-1 dysregulation in muscle with a concomitant local or systemic inflammatory reaction. In this review, we outline the function of PGC-1 coactivators in physiological and pathological conditions as well as the complex interplay of metabolic dysregulation and inflammation in obesity with special focus on skeletal muscle. We further put forward the hypothesis that, in this tissue, oxidative metabolism and inflammatory processes mutually antagonize each other. The nuclear factor ÎșB (NF-ÎșB) pathway thereby plays a key role in linking metabolic and inflammatory programs in muscle cells. We conclude this review with a perspective about the consequences of such a negative crosstalk on the immune system and the possibilities this opens for clinical applications
Representation of Global and National Conservation Priorities by Colombia's Protected Area Network
Improved production of the recombinant phospholipase A1 from Polybia paulista wasp venom expressed in bacterial cells for use in routine diagnostics
Measurements of neutrino oscillation parameters from the T2K experiment using 3.6 x 1021 protons on target
Measurements of neutrino oscillation parameters from the T2K experiment using protons on target
International audienceThe T2K experiment presents new measurements of neutrino oscillation parameters using protons on target (POT) in (anti-)neutrino mode at the far detector (FD). Compared to the previous analysis, an additional POT neutrino data was collected at the FD. Significant improvements were made to the analysis methodology, with the near-detector analysis introducing new selections and using more than double the data. Additionally, this is the first T2K oscillation analysis to use NA61/SHINE data on a replica of the T2K target to tune the neutrino flux model, and the neutrino interaction model was improved to include new nuclear effects and calculations. Frequentist and Bayesian analyses are presented, including results on and the impact of priors on the measurement. Both analyses prefer the normal mass ordering and upper octant of with a nearly maximally CP-violating phase. Assuming the normal ordering and using the constraint on from reactors, using Feldman--Cousins corrected intervals, and using constant intervals. The CP-violating phase is constrained to using Feldman--Cousins corrected intervals, and is excluded at more than 90% confidence level. A Jarlskog invariant of zero is excluded at more than credible level using a flat prior in , and just below using a flat prior in . When the external constraint on is removed, , in agreement with measurements from reactor experiments. These results are consistent with previous T2K analyses
First measurement of muon neutrino charged-current interactions on hydrocarbon without pions in the final state using multiple detectors with correlated energy spectra at T2K
This paper reports the first measurement of muon neutrino charged-current interactions without pions in the final state using multiple detectors with correlated energy spectra at T2K. The data was collected on hydrocarbon targets using the off-axis T2K near detector (ND280) and the on-axis T2K near detector (INGRID) with neutrino energy spectra peaked at 0.6 GeV and 1.1 GeV, respectively. The correlated neutrino flux presents an opportunity to reduce the impact of the flux uncertainty and to study the energy dependence of neutrino interactions. The extracted double-differential cross sections are compared to several Monte Carlo neutrino-nucleus interaction event generators showing the agreement between both detectors individually and with the correlated result