Insights on the laccase extraction and activity in ionic-liquid-based aqueous biphasic systems

Due to their catalytic properties, selectivity, and efficiency, enzymes are excellent biocatalysts. In particular, laccases are versatile multi-copper oxidases with great interest for a wide plethora of biotechnological and environmental applications. Even though several laccase-catalysed processes have been reported at an industrial level, the high costs of their downstream processing required to provide biocatalysts with high purity levels, stability and activity remains one of the main drawbacks when economically evaluating the overall processes. Aqueous biphasic systems based on ionic liquids (ILs) can be foreseen as a promising alternative approach for the extraction and activity maintenance/improvement of enzymes, essentially due to the designer solvents ability of ionic liquids. However, to take advantage of this feature and to use the full potential of IL-based aqueous biphasic systems, it is necessary to understand the effect of ILs as phase-forming constituents and how they affect the enzymes extraction and activity. In order to overcome the lack of information on this topic in the literature, in this work, IL-based aqueous biphasic systems were investigated to extract and enhance the laccase activity, in order to gather evidences that could be used to improve the enzymes downstream processing. To this end, a wide screening of imidazolium-, pyridinium-, pyrrolidinium-, piperidinium-, tetraalkylphosphonium-, and tetraalkylammonium-based ILs as phase-forming components of ABS was carried out. Furthermore, these ILs were used to create ABS combined with salts, polymers and used as adjuvants in polymer-based ABS. Most ABS comprising ILs revealed to be highly efficient extraction platforms, allowing the complete extraction of laccase for all the conditions tested, and with an enzyme activity enhancement by more than 50%. Overall, the obtained results demonstrate that laccase preferentially partitions to the most hydrophilic phase in ABS comprising ILs, both used as adjuvants or as phase-forming components, corresponding to the phase in which the IL is enriched. Furthermore, the IL chemical structure of the IL plays a significant role in the enzyme activity, where ILs with a higher number of hydroxyl groups seem to be relevant to improve the laccase activity.publishe

Plasma Lipases And Lipid Transfer Proteins Increase Phospholipid But Not Free Cholesterol Transfer From Lipid Emulsion To High Density Lipoproteins

Background: Plasma lipases and lipid transfer proteins are involved in the generation and speciation of high density lipoproteins. In this study we have examined the influence of plasma lipases and lipid transfer protein activities on the transfer of free cholesterol (FC) and phospholipids (PL) from lipid emulsion to human, rat and mouse lipoproteins. The effect of the lipases was verified by incubation of labeled (3H-FC, 14C-PL) triglyceride rich emulsion with human plasma (control, post-heparin and post-heparin plus lipase inhibitor), rat plasma (control and post-heparin) and by the injection of the labeled lipid emulsion into control and heparinized functionally hepatectomized rats. Results: In vitro, the lipase enriched plasma stimulated significantly the transfer of 14C-PL from emulsion to high density lipoprotein (p<0.001) but did not modify the transfer of 3H-FC. In hepatectomized rats, heparin stimulation of intravascular lipolysis increased the plasma removal of 14C-PL and the amount of 14C-PL found in the low density lipoprotein density fraction but not in the high density lipoprotein density fraction. The in vitro and in vivo experiments showed that free cholesterol and phospholipids were transferred from lipid emulsion to plasma lipoproteins independently from each other. The incubation of human plasma, control and control plus monoclonal antibody anti-cholesteryl ester transfer protein (CETP), with 14C-PL emulsion showed that CETP increases 14C-PL transfer to human HDL, since its partial inhibition by the anti-CETP antibody reduced significantly the 14C-PL transfer (p<0.05). However, comparing the nontransgenic (no CETP activity) with the CETP transgenic mouse plasma, no effect of CETP on the 14C-PL distribution in mice lipoproteins was observed. Conclusions: It is concluded that: 1-intravascular lipases stimulate phospholipid transfer protein mediated phospholipid transfer, but not free cholesterol, from triglyceride rich particles to human high density lipoproteins and rat low density lipoproteins and high density lipoproteins; 2-free cholesterol and phospholipids are transferred from triglyceride rich particles to plasma lipoproteins by distinct mechanisms, and 3 - CETP also contributes to phospholipid transfer activity in human plasma but not in transgenic mice plasma, a species which has high levels of the specific phospholipid transfer protein activity.219Backer, G., Bacquer, D., Konitzer, M., Epidemiological aspects of high density lipoprotein cholesterol (1998) Atherosclerosis, 137, pp. S1-S6Stein, O., Stein, Y., Atheroprotective mechanisms of HDL (1999) Atherosclerosis, 144, pp. 285-301Tall, A.R., Plasma lipid transfer proteins (1995) Annu Rev Biochem, 64, pp. 235-257Hesler, B., Tall, A.R., Swenson, T.L., Weech, P.K., Marcel, Y.L., Milne, R.W., Monoclonal antibody to the Mr 74000 cholesterol ester transfer protein neutralize all of the cholesterol ester and triglyceride transfer activities in human plasma (1988) J Biol Chem, 263, pp. 5020-5023Swenson, T.L., Brocia, R.W., Tall, A.R., Plasma cholesteryl ester transfer protein has binding sites for neutral lipids and phospholipids (1988) J Biol Chem, 263, pp. 5150-5157Lagrost, L., Athias, A., Gambert, P., Lallemant, C., Comparative study of phospholipid transfer activities mediated by cholesteryl ester transfer protein and phospholipid transfer protein (1994) J Lipid Res, 35, pp. 825-835Tato, F., Vega, G.L., Grundy, S.M., Determinants of plasma HDL-cholesterol in hypertriglyceridemic patients (1997) Arterioscler Thromb Vasc Biol, 17, pp. 56-63Tall, A.R., Forester, L.R., Bongiovanni, G.L., Facilitation of phosphatidylcholine transfer into HDL lipoproteins by an apolipoprotein in the density 1.20-1.26 g/ml fraction of plasma (1983) J Lipid Res, 24, pp. 277-289Albers, J.J., Tollefson, J.H., Chen, C.H., Steinmetz, A., Isolation and characterization of human plasma lipid transfer proteins (1984) Arteriosclerosis, 4, pp. 49-58Guyard-Dangremont, V., Desrumaux, C., Gambert, P., Lallemant, C., Lagrost, L., Phospholipid and cholesteryl ester transfer activities in plasma from 14 vertebrate species. Relation to atherogenesis susceptibility (1998) Comp Biochem Physiol Biochem Mol Biol, 120, pp. 517-525Tall, A.R., Krumholz, S., Olivecrona, T., Deckelbaum, R.J., Plasma phospholipid transfer protein enhances transfer and exchange of phospholipids between VLDL and HDL lipoproteins during lipolysis (1985) J Lipid Res, 26, pp. 842-851Nishida, H.I., Nishida, T., Phospholipid transfer protein mediates transfer of not only phosphatidylcholine but also cholesterol from phosphatidylcholine-cholesterol vesicles to high density lipoproteins (1997) J Biol Chem, 272, pp. 6959-6964Lagrost, L., Desrumaux, C., Masson, D., Deckert, V., Gambert, P., Structure and function of the plasma phospholipid transfer protein (1998) Curr Opin Lipidol, 9, pp. 203-209Albers, J.J., Tu, A.Y., Paigen, B., Chen, H., Cheung, M.C., Marcovina, S.M., Transgenic mice expressing human phospholipid transfer protein have increased HDL/non-HDL cholesterol ratio (1996) Int J Clin Lab Res, 26, pp. 262-267Foger, B., Santamarina-Fojo, S., Shamburek, R.D., Parrot, C.L., Talley, G.D., Brewer Jr., H.B., Plasma phospholipid transfer protein. Adenovirus-mediated overexpression in mice leads to decreased plasma high density lipoprotein (HDL) and enhanced hepatic uptake of phospholipids and cholesteryl esters from HDL (1997) J Biol Chem, 272, pp. 27393-27400Redgrave, T.G., Small, D.M., Quantitation of the transfer of surface phospholipid of chylomicrons to the HDL lipoprotein fraction during the catabolism of chylomicrons in the rat (1979) J Clin Invest, 64, pp. 162-171Tall, A.R., Green, P.H., Glickman, R.M., Riley, J.W., Metabolic fate of chylomicron phospholipids and apoproteins in the rat (1979) J Clin Invest, 64, pp. 977-989Tall, A.R., Blum, C.B., Forester, G.P., Nelson, C.A., Changes in the distribution and composition of plasma HDL liproteins after ingestion of fat (1982) J Biol Chem, 257, pp. 198-207Groot, H., Scheek, L.M., Effects of fat ingestion on HDL profiles in human sera (1984) J Lipid Res, 25, pp. 684-692Brunzell, J.D., Familial lipoprotein lipase deficiency and other causes of the chylomicronemia syndrome (1995) Metabolic & Molecular Bases of Inherited Disease, pp. 1913-1932. , Scriver, CR, Beaudet, AL, Sly, WS, ed, McGraw-Hill Inc, New York, 7th edBijvoet, S., Gagne, S.E., Moorjani, S., Gagne, C., Henderson, H.E., Fruchart, J.C., Dallongeville, J., Hayden, M.R., Alterations in plasma lipoproteins and apolipoproteins before the age of 40 in heterozygotes for lipoprotein lipase deficiency (1996) J Lipid Res, 37, pp. 640-650Kuusi, T., Ehnholm, C., Viikari, J., Harkonen, R., Vartiainen, E., Puska, P., Taskinen, M.-R., Postheparin plasma lipoprotein and hepatic lipase are determinants of hypo- and hyperalphalipoproteinemia (1989) J Lipid Res, 30, pp. 1117-1126Liu, S., Jirik, F.R., LeBoeuf, R.C., Henderson, H., Castellani, L.W., Lusis, A.J., Ma, Y., Kirk, E., Alteration of lipid profiles in plasma of transgenic mice expressing human lipoprotein lipase (1994) J Biol Chem, 269, pp. 11417-11424Weinstock, P.H., Bisgaier, C.L., Aalto-Setala, K., Radner, H., Ramakrishnan, R., Levak-Frank, S., Essenburg, A.D., Breslow, J.L., Severe hypertriglyceridemia, reduced high density lipoprotein, and neonatal death in lipoprotein lipase knockout mice. Mild hypertriglyceridemia with impaired very low density lipoprotein clearance in heterozygotes (1995) J Clin Invest, 96, pp. 2555-2568Applebaum-Bowden, D., Kobayashi, J., Kashyap, V.S., Brown, D.R., Berard, A., Meyn, S., Parrott, C., Santamarina-Fojo, S., Hepatic lipase gene therapy in hepatic lipase-deficient mice. Adenovirus-mediated replacement of a lipolytic enzyme to the vascular endothelium (1996) J Clin Invest, 97, pp. 799-805Gillett, M.P., Vieira, E.M., Dimenstein, R., The phospholipase activities present in preheparin mouse plasma are inhibited by antiserum to hepatic lipase (1993) Int J Biochem, 25, pp. 449-453Ha, Y.C., Barter, P.J., Differences in plasma cholesteryl ester transfer activity in sixteen vertebrate species (1982) Comp Biochem Physiol B, 71, pp. 265-269Clee, S.M., Zhang, H., Bissada, N., Miao, L., Ehrenborg, E., Benlian, P., Shen, G.X., Hayden, M.R., Relationship between lipoprotein lipase and HDL lipoprotein cholesterol in mice: Modulation by cholesteryl ester transfer protein and dietary status (1997) J Lipid Res, 38, pp. 2079-2089Oliveira, H.C.F., Hirata, M.H., Redgrave, T.G., Maranhão, R.C., Competition between chylomicrons and their remnants for plasma removal: A study with artificial emulsion models of chylomicrons (1988) Biochim Biophys Acta, 958, pp. 211-217Nakandakare, E.R., Lottenberg, S.A., Oliveira, H.C.F., Bertolami, M.C., Vasconcelos, K.S., Sperotto, G., Quintão, E.C., Simultaneous measurements of chylomicron lipolysis and remnant removal using a doubly labeled artificial lipid emulsion: Studies in normolipidemic and hyperlipidemic subjects (1994) J Lipid Res, 35, pp. 143-152Jiao, S., Cole, T.G., Kitchens, R.T., Pfleger, B., Schonfeld, G., Genetic heterogeneity of lipoproteins in inbred strains of mice: Analysis by gel-permeation chromatography (1990) Metabolism, 39, pp. 155-160Ehnholm, C., Kuusi, T., Preparation, characterization and measurement of hepatic lipase (1986) Methods Enzymol, 129, pp. 716-738Oliveira, H.C.F., Quintão, E.C., 'In vitro' cholesteryl ester bidirectional flow between high-density lipoproteins and triglyceride-rich emulsions: Effects of particle concentration and composition, cholesteryl ester transfer activity and oleic acid (1996) J Biochem Biophys Methods, 32, pp. 45-57Huff, M.W., Miller, D.B., Wolf, B.M., Connelly, P.W., Sawyez, C.G., Uptake of hypertriglyceridemic VLDL and their remnants by HepG2 cells: The role of lipoprotein lipase, hepatic triglyceride lipase, and cell surface proteoglycans (1997) J Lipid Res, 38, pp. 1318-1333Marques-Vidal, P., Jauhiainen, M., Metso, J., Ehnholm, C., Transformation of HDL2 particles by hepatic lipase and phospholipid transfer protein (1997) Atherosclerosis, 133, pp. 87-96Murdoch, S.J., Breckenridge, W.C., Effect of lipid transfer proteins on lipoprotein lipase induced transformation of VLDL and HDL (1996) Biochim Biophys Acta, 1303, pp. 222-232Murdoch, S.J., Breckenridge, W.C., Influence of lipoprotein lipase and hepatic lipase on the transformation of VLDL and HDL during lipolysis of VLDL (1995) Atherosclerosis, 118, pp. 193-212Patsch, J.R., Gotto Jr., A.M., Olivercrona, T., Eisenberg, S., Formation of HDL2-like particles during lipolysis of VLDL in vitro (1978) Proc Natl Acad Sci USA, 75, pp. 4519-4523Gillett, M.P., Costa, E.M., Owen, J.S., The phospholipase activities present in preheparin mouse plasma are inhibited by antiserum to hepatic lipase (1980) Biochim Biophys Acta, 617, pp. 237-244Peterson, J., Bengtsson-Olivecrona, G., Olivecrona, T., Mouse preheparin plasma contains high levels of hepatic lipase with low affinity for heparin (1986) Biochim Biophys Acta, 87, pp. 865-870O'Meara, N.M., Cabana, V.G., Lukens, J.R., Loharikar, B., Forte, T.M., Polonsky, K.S., Getz, G.S., Heparin-induced lipolysis in hypertriglyceridemic subjects results in the formation of atypical HDL particle (1994) J Lipid Res, 35, pp. 2178-219

Curricular orientations to real-world contexts in mathematics

A common claim about mathematics education is that it should equip students to use mathematics in the ‘real world’. In this paper, we examine how relationships between mathematics education and the real world are materialised in the curriculum across a sample of eleven jurisdictions. In particular, we address the orientation of the curriculum towards application of mathematics, the ways that real-world contexts are positioned within the curriculum content, the ways in which different groups of students are expected to engage with real-world contexts, and the extent to which high-stakes assessments include real-world problem solving. The analysis reveals variation across jurisdictions and some lack of coherence between official orientations towards use of mathematics in the real world and the ways that this is materialised in the organisation of the content for students

Ionic liquid-mediated recovery of carotenoids from the bactris gasipaes fruit waste and their application in food-packaging chitosan films

In this work, a process for the extraction and purification of carotenoids from the fruit Bactris gasipaes was developed. Ethanolic and aqueous solutions of ionic liquids (ILs) and surfactants were evaluated on the extraction of these pigments. Thus, we developed an optimized sustainable downstream process mediated by the best solvent with further isolation of the carotenoids and the recyclability of the IL used. The process was characterized not only in terms of efficiency but also regarding its environmental impact. The recyclability of the solvents as well as the high efficiency (maximum yield of extraction of carotenoids = 88.7 ± 0.9 μgcarotenoids·gdried biomass–1) and the low environmental impact of the integrated process developed in this work were demonstrated. In the end, in order to incorporate functional activity for an alternative food-packaging material, carotenoids were successfully applied on the preparation of chitosan-based films with excellent results regarding their mechanical parameters and antioxidant activity.publishe

Basis Functions for Linear-Scaling First-Principles Calculations

In the framework of a recently reported linear-scaling method for density-functional-pseudopotential calculations, we investigate the use of localized basis functions for such work. We propose a basis set in which each local orbital is represented in terms of an array of `blip functions'' on the points of a grid. We analyze the relation between blip-function basis sets and the plane-wave basis used in standard pseudopotential methods, derive criteria for the approximate equivalence of the two, and describe practical tests of these criteria. Techniques are presented for using blip-function basis sets in linear-scaling calculations, and numerical tests of these techniques are reported for Si crystal using both local and non-local pseudopotentials. We find rapid convergence of the total energy to the values given by standard plane-wave calculations as the radius of the linear-scaling localized orbitals is increased.Comment: revtex file, with two encapsulated postscript figures, uses epsf.sty, submitted to Phys. Rev.

Development of electrospun photocatalytic TiO2-polyamide-12 nanocomposites

Titanium dioxide (TiO2) in different forms such as films, fibers or particles are being extensively studied for removal of contaminants from aquatic environments due to its outstanding photocatalytic activity. This work reports the development of TiO2-polyamide 12 electrospun fiber mats. A systematic study on the influence of electrospun processing parameters on polymer fiber morphology was performed. It was observed that the average fiber diameter is mainly influenced by polymer concentration and average fiber diameters between 404 ± 82 nm and 1442 ± 360 nm were obtained. Polyamide-12 (PA-12) was used as a polymer matrix and electrospun with 0, 10 and 20 wt% of TiO2. It was observed that the filler does not change the average fiber diameter, being similar to that observed for neat PA-12 fibers processed under the same experimental conditions. The TiO2 were particles dispensed not only in the bulk of the polymeric matrix but also on the surface of the fibers, especially for the samples with higher filler contents. Neat and nanocomposite electrospun samples show a hydrophobic behavior and a degree of crystallinity of ~25%. The photocatalytic performance of the processed samples was measured by following the degradation capability of a chosen dye, methylene blue (MB). Results show that the nanocomposite samples have a remarkable photocatalytic activity, especially the one with a higher load of TiO2 particles (20 wt%), with all MB being removed from the solution after 100 min.This work was supported by FEDER through the COMPETE Program and by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Project PEST-C/FIS/ UI607/2014, and CNPq (Conselho Nacional de Desenvolvimento Científico e Tecnol ogico e Brazil). The authors also thank funding from “Matepro eOptimizing Materials and Processes”, ref. NORTE- 07-0124-FEDER-000037”, co-funded by the “Programa Operacional Regional do Norte” (ON.2 e O Novo Norte), under the “Quadro de Refer^encia Estrat egico Nacional” (QREN), through the “Fundo Europeu de Desenvolvimento Regional” (FEDER). PM thanks the FCT for the, SFRH/BD/98616/2013 grant. VS and SLM also thank support from the COST Action MP1206 “Electrospun Nano-fibers for bio inspired composite materials and innovative industrial applications”. VS thanks the EIS Faculty at UOW for the starting grant

Measurement of the polarisation of W bosons produced with large transverse momentum in pp collisions at sqrt(s) = 7 TeV with the ATLAS experiment

This paper describes an analysis of the angular distribution of W->enu and W->munu decays, using data from pp collisions at sqrt(s) = 7 TeV recorded with the ATLAS detector at the LHC in 2010, corresponding to an integrated luminosity of about 35 pb^-1. Using the decay lepton transverse momentum and the missing transverse energy, the W decay angular distribution projected onto the transverse plane is obtained and analysed in terms of helicity fractions f0, fL and fR over two ranges of W transverse momentum (ptw): 35 < ptw < 50 GeV and ptw > 50 GeV. Good agreement is found with theoretical predictions. For ptw > 50 GeV, the values of f0 and fL-fR, averaged over charge and lepton flavour, are measured to be : f0 = 0.127 +/- 0.030 +/- 0.108 and fL-fR = 0.252 +/- 0.017 +/- 0.030, where the first uncertainties are statistical, and the second include all systematic effects.Comment: 19 pages plus author list (34 pages total), 9 figures, 11 tables, revised author list, matches European Journal of Physics C versio