A New Ultrasensitive Bioluminescence-Based Method for Assaying Monoacylglycerol Lipase

A novel bioluminescent Monoacylglycerol lipase (MAGL) substrate 6-O-arachidonoylluciferin, a D-luciferin derivative, was synthesized, physico-chemically characterized, and used as highly sensitive substrate for MAGL in an assay developed for this purpose. We present here a new method based on the enzymatic cleavage of arachidonic acid with luciferin release using human Monoacylglycerol lipase (hMAGL) followed by its reaction with a chimeric luciferase, PLG2, to produce bioluminescence. Enzymatic cleavage of the new substrate by MAGL was demonstrated, and kinetic constants Km and Vmax were determined. 6-O-arachidonoylluciferin has proved to be a highly sensitive substrate for MAGL. The bioluminescence assay (LOD 90 pM, LOQ 300 pM) is much more sensitive and should suffer fewer biological interferences in cells lysate applications than typical fluorometric methods. The assay was validated for the identification and characterization of MAGL modulators using the well-known MAGL inhibitor JZL184. The use of PLG2 displaying distinct bioluminescence color and kinetics may offer a highly desirable opportunity to extend the range of applications to cell-based assays.     

Bridging the gap between Graetz's and lévêque's analyses for mass/heat transfer in a channel with uniform concentration or flux at the wall

A new approximate solution which bridges the gap between the classical theories of Graetz and Lévêque for heat/mass transfer in channel flow is presented. The results include expressions, uniformly valid in the axial direction, for the mixing‐cup concentration (or temperature) profile 〈c〉 when transport towards the wall is slow (Dirichlet limit), and for the Sherwood number Sh when the wall flux can be considered uniform (Neumann limit). The technique employed provides insight into the mathematical structure of both quantities 〈c〉 (or conversion X_R) and Sh identifying explicitly the contributions from fully developed and developing behaviors, while maintaining accuracy in the transition region. Criteria to bound the different convection‐diffusion regimes are suggested, which critically systematize previous results. These results are important for model selection in the design and simulation, among others, of heat exchangers and wall‐coated microreactors where fast heterogeneous reactions occur. © 2011 American Institute of Chemical Engineers AIChE J, 58: 1880–1892, 2012     

Selective linear dimerization of 1,3-butadiene by palladium compounds immobilized into 1-n-butyl-3-methyl imidazolium ionic liquids

Summary Palladium (II) compounds (palladium dichloride, acetate and acetylacetonate) in conjunction with triphenylphosphine dissolved in 1-butyl-methyl imidazolium tetrafluoroborate, hexafluorophosphate or trifluoromethanesulfonate are able to dimerize butadiene into 1,3,6-octatriene in a typical two-phase catalytic reaction with 100% selectivity. The reaction product is easily separated from the reaction mixture by simple decantation, and the recovered ionic liquid catalyst solution can be reused several times without significant changes in catalytic activity or selectivity. Received: 24 November 1997/Revised version: 5 January 1998/Accepted: 7 January 1998     

Effects of Aging and Hypercholesterolemia on Oxidative Stress and DNA Damage in Bone Marrow Mononuclear Cells in Apolipoprotein E-deficient Mice

Recent evidence from apolipoprotein E-deficient (apoE^−/−) mice shows that aging and atherosclerosis are closely associated with increased oxidative stress and DNA damage in some cells and tissues. However, bone marrow cells, which are physiologically involved in tissue repair have not yet been investigated. In the present study, we evaluated the influence of aging and hypercholesterolemia on oxidative stress, DNA damage and apoptosis in bone marrow cells from young and aged apoE^−/− mice compared with age-matched wild-type C57BL/6 (C57) mice, using the comet assay and flow cytometry. The production of both superoxide and hydrogen peroxide in bone marrow cells was higher in young apoE^−/− mice than in age-matched C57 mice, and reactive oxygen species were increased in aged C57 and apoE^−/− mice. Similar results were observed when we analyzed the DNA damage and apoptosis. Our data showed that both aging and hypercholesterolemia induce the increased production of oxidative stress and consequently DNA damage and apoptosis in bone marrow cells. This study is the first to demonstrate a functionality decrease of the bone marrow, which is a fundamental extra-arterial source of the cells involved in vascular injury repair.     

Foods native to indigenous and afro-descendents in Colombia

For social programs in Colombia, like those administered by the Instituto Colombiano de Bienestar Familiar (ICBF), it's important to know what native foods minority groups consume. This research obtained information on native foods consumed by indigenous and afro-descendents living in 10 Colombian departments: Cauca, Nari?o, Amazonas, Chocó, Guainia, Vichada, Magdalena, Guajira, Cesar y Vaupés. A questionnaire was applied to key informants (individually or in groups), addressing the following topics: personal information on the informant, name and type of food, if consumed by indigenous and/or afro-Colombians, climate where produced, time of year when harvested, if consumed raw or cooked, preparations, properties ascribed to the food, and current production, use and availability. Key informants included participants in ICBF's programs, indigenous authorities, teachers, traditional healers, and others, under the supervision of professionals from ICBF's mobile unit in each department. Bibliography (n = 123 documents) was compiled and reviewed. In the departments selected, 13 municipalities were visited, 139 individuals were interviewed and at least 92 new foods (i.e., not currently included in the Colombian Food Composition Table) were identified. Among the 92, the scientific name was obtained for 62 foods. Of these, 2 were classified as other, 18 as meats, 3 as insects, and 39 as plants. Among the plants, informants mentioned fruit (n=29), leaves (n=4), seed (n=3) and roots (n=3). Indigenous and afro-descendent communities in Colombia report consuming dozens of foods that are not currently in the Colombian Food Composition Table.     

Aerodynamic effects of trees on pollutant concentration in street canyons

This paper deals with aerodynamic effects of avenue-like tree planting on flow and traffic-originated pollutant dispersion in urban street canyons by means of wind tunnel experiments and numerical simulations. Several parameters affecting pedestrian level concentration are investigated, namely plant morphology, positioning and arrangement. We extend our previous work in this novel aspect of research to new configurations which comprise tree planting of different crown porosity and stand density, planted in two rows within a canyon of street width to building height ratio W/H = 2 with perpendicular approaching wind. Sulfur hexafluoride was used as tracer gas to model the traffic emissions. Complementary to wind tunnel experiments, 3D numerical simulations were performed with the Computational Fluid Dynamics (CFD) code FLUENT™ using a Reynolds Stress turbulence closure for flow and the advection-diffusion method for concentration calculations. In the presence of trees, both measurements and simulations showed considerable larger pollutant concentrations near the leeward wall and slightly lower concentrations near the windward wall in comparison with the tree-less case. Tree stand density and crown porosity were found to be of minor importance in affecting pollutant concentration. On the other hand, the analysis indicated that W/H is a more crucial parameter. The larger the value of W/H the smaller is the effect of trees on pedestrian level concentration regardless of tree morphology and arrangement. A preliminary analysis of approaching flow velocities showed that at low wind speed the effect of trees on concentrations is worst than at higher speed. The investigations carried out in this work allowed us to set up an appropriate CFD modelling methodology for the study of the aerodynamic effects of tree planting in street canyons. The results obtained can be used by city planners for the design of tree planting in the urban environment with regard to air quality issues.     

Consumer preferences for fresh tomato at the European scale: a common segmentation on taste and firmness

Although tomato flavor has not been a major goal for breeders, nowadays it becomes important as it is a subject of consumer complaint. A better knowledge of tomato consumer preferences, at the European level, should provide the basis for improvement of fruit quality and for market segmentation. In the framework of a large European project, 806 consumers from 3 countries, The Netherlands, France, and Italy, were presented with a set of 16 varieties representing the diversity of fresh tomato offer in order to evaluate their preferences. In parallel, sensory profiles were constructed by expert panels in each country. Preference maps were then constructed in each country revealing the structure of consumer preferences and allowing identification of the most important characteristics. Then a global analysis revealed that preferences were quite homogeneous across countries. This study identified the overall flavor and firmness as the most important traits for improving tomato fruit quality. It showed that consumer preferences from different European countries, with different cultures and food practices, are segmented following similar patterns when projected onto a common referential plan. Moreover, the results clearly showed that diversification of taste and texture is required to satisfy all consumers' expectations as some consumers preferred firm tomatoes, while others preferred melting ones and were more or less demanding in terms of sweetness and flavor intensity. Detailed comparisons also showed the importance of the fruit appearance in consumer preference.     

Palladium(0) allylic alkylation in a two-phase system or with a supported aqueous phase catalyst

The reaction of allylic carbonates with various acyclic and cyclic carbonucleophiles is catalyzed by the system Pd(OAc)₂ and P(C₆H₄-m-SO₃Na)₃ (or tppts) in a two-phase liquid medium H₂O-nitrile, the activity of the catalyst depending mainly on the nature of the nitrile, the temperature of the reaction and the ratio palladium/tppts. The same system Pd(OAc)₂ and P(C₆H₄-m-SO₃Na)₃ supported on silica catalyzes also this reaction. The formation of the active palladium species in the two cases is followed by

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NMR spectroscopy and discussed.     

Broad-Spectrum Bactericidal Activity of a Synthetic Random Copolymer Based on 2-Methoxy-6-(4-Vinylbenzyloxy)-Benzylammonium Hydrochloride

Low-molecular-weight organic ammonium salts exert excellent antimicrobial effects by interacting lethally with bacterial membranes. Unfortunately, short-term functionality and high toxicity limit their clinical application. On the contrary, the equivalent macromolecular ammonium salts, derived from the polymerization of monomeric ammonium salts, have demonstrated improved antibacterial potency, a lower tendency to develop resistance, higher stability, long-term activity, and reduced toxicity. A water-soluble non-quaternary copolymeric ammonium salt (P7) was herein synthetized by copolymerizing 2-methoxy-6-(4-vinylbenzyloxy)-benzylammonium hydrochloride monomer with N, N-di-methyl-acrylamide. The antibacterial activity of P7 was assessed against several multidrug-resistant (MDR) clinical isolates of both Gram-positive and Gram-negative species. Except for colistin-resistant Pseudomonas aeruginosa, most isolates were susceptible to P7, also including some Gram-negative bacteria with a modified charge in the external membrane. P7 showed remarkable antibacterial activity against isolates of Enterococcus, Staphylococcus, Acinetobacter, and Pseudomonas, and on different strains of Escherichia coli and Stenotrophomonas maltophylia, regardless of their antibiotic resistance. The lowest minimal inhibitory concentrations (MICs) observed were 0.6–1.2 µM and the minimal bactericidal concentrations (MBC) were frequently overlapping with the MICs. In 24-h time–kill and turbidimetric studies, P7 displayed a rapid non-lytic bactericidal activity. P7 could therefore represent a novel and potent tool capable of counteracting infections sustained by several bacteria that are resistant to the presently available antibiotics.