Bioassay-guided fractionation of Larix laricina du Roi, and antidiabetic potentials of ethanol and hot water extracts of seventeen medicinal plants from the traditional pharmacopeia of the James Bay Cree

Nous avons utilisé une approche ethnobotanique pour identifier des espèces de plantes utilisées par les Cris afin de traiter les symptômes du diabète de type 2. Larix laricina du Roi (L. laricina) a récemment été identifiée comme une des meilleures plantes qui a stimulé le transport de glucose dans les cellules C2C12 et fortement potentialisé la différenciation des 3T3-L1 en indiquant une sensibilité potentiellement accrue à l’insuline. Ensuite, ces études de criblage ont été effectuées sur des extraits éthanolique (EE) en utilisant une série de bioessais in vitro. Cependant, les préparations traditionnelles des plantes sont souvent faites avec l’eau chaude. Le but de cette thèse de doctorat était d’isoler les principes actifs de L. laricina par un fractionnement guidé par l’adipogenèse; d’évaluer et de comparer l’activité et les mécanismes antidiabétiques des EE et des extraits aqueux (HWE) de ces 17 plantes. Pour le fractionnement de L. laricina, on a isolé plusieurs composés connus et identifié un nouveau composé actif cycloartane triterpene, qui a amélioré fortement l’adipogenèse et a été responsable en partie de l’activité adipogénique (potentiellement similaire à l’effet sensibilisateur à l’insuline des glitazone) de l’extrait éthanolique issu de l’écorce de L. laricina. Pour le métabolisme lipidique, nos résultats ont confirmé que 10 parmi les 17 EE ont augmenté la différenciation des adipocytes alors que 2 extraits seulement l’ont inhibée. Les HWE ont montré une faible activité adipogénique ou antiadipogénique. Les EE de R. groenlandicum et K. angustifolia ont le PPAR γ (peroxisome proliferator-activated receptor γ), le SREBP-1 (sterol regulatory element binding protein-1) et le C/EBP (CCAAT-enhancer binding proteins) α, alors que ceux de P. balsamifera et A. incana les ont inhibés. L’effet inhibiteur de P. balsamifera a également été prouvé d’avoir impliqué l’activation de la protéine kinase activée par l’AMP (AMPK). Les EE et HWE de R. groenlandicum ont stimulé les mêmes facteurs de transcription alors que les extraits aqueux d’autres plantes sélectionnées ont perdu ces effets en comparaison avec leurs extraits éthanoliques respectifs. L’analyse phytochimique a également identifié le groupe des espèces actives et inactives, notamment lorsque les espèces ont été séparées par famille de plante. Finalement concernant l’homéostasie de glucose, nos résultats ont confirmé que plusieurs EE ont stimulé le transport de glucose musculaire et inhibé l’activité de la glucose-6-phosphatase (G6Pase) hépatique. Certains des HWE ont partiellement ou complètement perdu ces activités antidiabétiques par rapport aux EE, tandis qu’une seule plante (R.groenlandicum) a juste conservé un potentiel similaire entre les EE et HWE dans les deux essais. Dans les cellules musculaires, les EE de R.groenlandicum, A. incana et S. purpurea ont stimulé le transport de glucose en activant la voie de signalisation de l’AMPK et en augmentant le niveau d’expression des GLUT4. En comparaison avec les EE, les HWE de R.groenlandicum ont montré des activités similaires; les HWE de A. incana ont complètement perdu leur effet sur tous les paramètres étudiés; les HWE de S. purpurea ont activé la voie de l’insuline au lieu de celle de l’AMPK pour augmenter le transport de glucose. Dans les cellules H4IIE, les EE et HWE des 5 plantes ont activé la voie de l’AMPK, et en plus les EE et HWE de 2 plantes ont activé la voie de l’insuline. La quercétine-3-O-galactoside et la quercétine 3-O-α-L-arabinopyranoside ont été identifiées comme des composés ayant un fort potentiel antidiabétique et donc responsables de l'activité biologique des plantes HWE actifs avec le transport du glucose. En conclusion, on a isolé plusieurs composés connus et identifié un nouveau triterpène actif à partir du fractionnement de L. laricina. Nous avons fourni également une preuve directe pour l'évaluation et la comparaison d'une action analogue à l'insuline ou insulino-sensibilisateur des EE et HWE de plantes médicinales Cris au niveau de muscle, de foie et de tissus adipeux. Une partie de leur action peut être liée à la stimulation des voies de signalisation intracellulaire insulino-dépendante et non-insulino-dépendante, ainsi que l’activation de PPARγ. Nos résultats indiquent que les espèces de plantes, les tissus ou les cellules cibles, ainsi que les méthodes d'extraction sont tous des déterminants significatifs de l'activité biologique de plantes médicinales Cris sur le métabolisme glucidique et lipidique.

Effect of the Vulcanization Time and Storage on the Stability and Physical Properties of Sulfur-Prevulcanized Natural Rubber Latex

Prevulcanized natural rubber latex was prepared by the heating of the latex compound at 55°C for different periods of time (2, 4, 6, 8, and 10 h). The changes in the colloidal stability and physical properties were evaluated during the course of prevulcanization. The prevulcanized latex compounds were stored for 300 days, and the properties were monitored at different storage intervals (0, 20, 40, 60, 120, 180, 240, and 300 days). During prevulcanization, the mechanical stability time increased, and the viscosity remained almost constant. The tensile strength increased during storage for a period of 20 days. The degree of crosslinking, modulus, elongation at break, and chloroform number were varied with the time of storage.

Development of nitrifying and photosynthetic sulfur bacteria based bioaugmentation systems for the bioremediation of ammonia and hydrogen sulphide in shrimp culture

This thesis entitled Development of nitrifying ans photosynthetic sulfur bacteria based bioaugmentation systems for the bioremediation of ammonia and hydregen sulphide in shrimp culture. the thesis is to propose a sustainable, low cost option for the mitigation of toxic ammonia and hydrogen sulphide in shrimp culture systems. Use of ‘bioaugmentors’ as pond additives is an emerging field in aquaculture. Understanding the role of organisms involved in the ‘bioaugmentor’ will obviously help to optimize conditions for their activity.The thesis describes the use of wood powder immobilization of nitrifying consortia.Shrimp grow out systems are specialized and highly dynamic aquaculture production units which when operated under zero exchange mode require bioremediation of ammonia, nitrite nitrogen and hydrogen sulphide to protect the crop. The research conducted here is to develop an economically viable and user friendly technology for addressing the above problem. The nitrifying bacterial consortia (NBC) generated earlier (Achuthan et al., 2006) were used for developing the technology.Clear demonstration of better quality of immobilized nitrifiers generated in this study for field application.

Fractionation and bioavailability of phosphorus in a tropical estuary, Southwest India

Phosphorus fractionation was employed to find the bioavailability of phosphorus and its seasonal variations in the Panangad region of Cochin estuary, the largest estuarine system in the southwest coast of India. Sequential extraction of the surficial sediments using chelating agents was taken as a tool for this. Phosphate in the water column showed seasonal variations, with high values during the monsoon months, suggesting external runoff. Sediment texture was found to be the main factor influencing the spatial distribution of the geochemical parameters in the study region. Similarly, total phosphorus also showed granulometric dependence and it ranged between 319.54 and 2,938.83 μg/g. Calcium-bound fraction was the main phosphorus pool in the estuary. Significant spatial variations were observed for all bioavailable fractions; iron-bound inorganic phosphorus (5.04–474.24 μg/g), calcium-bound inorganic phosphorus (11.16–826.09 μg/g), and acidsoluble organic phosphorus (22.22–365.86 μg/g). Among the non-bioavailable phosphorus, alkalisoluble organic fraction was the major one (51.92– 1,002.45 μg/g). Residual organic phosphorus was K. R. Renjith (B) · N. Chandramohanakumar · M. M. Joseph Department of Chemical Oceanography, School of Marine Sciences, Cochin University of Science and Technology, Kochi 682016, Kerala, India e-mail: renjithaqua@gmail.com comparatively smaller fraction (3.25–14.64% of total). The sandy and muddy stations showed distinct fractional composition and the speciation study could endorse the overall geochemical character. There could be buffering of phosphorus, suggested by the increase in the percentage of bioavailable fractions during the lean premonsoon period, counteracting the decreases in the external loads. Principal component analysis was employed to find the possible processes influencing the speciation of phosphorus in the study region

Geochemical metal fractionation profile of the core sediment in the Cochin estuarine system

Geochemical composition is a set of data for predicting the climatic condition existing in an ecosystem. Both the surficial and core sediment geochemistry are helpful in monitoring, assessing and evaluating the marine environment. The aim of the research work is to assess the relationship between the biogeochemical constituents in the Cochin Estuarine System (CES), their modifications after a long period of anoxia and also to identify the various processes which control the sediment composition in this region, through a multivariate statistical approach. Therefore the study of present core sediment geochemistry has a critical role in unraveling the benchmark of their characterization. Sediment cores from four prominent zones of CES were examined for various biogeochemical aspects. The results have served as rejuvenating records for the prediction of core sediment status prevailing in the CES

Quantifying the effects of perturbing the physics of an interactive sulfur scheme using an ensemble of GCMs on the climateprediction.net platform

Aerosols from anthropogenic and natural sources have been recognized as having an important impact on the climate system. However, the small size of aerosol particles (ranging from 0.01 to more than 10 μm in diameter) and their influence on solar and terrestrial radiation makes them difficult to represent within the coarse resolution of general circulation models (GCMs) such that small-scale processes, for example, sulfate formation and conversion, need parameterizing. It is the parameterization of emissions, conversion, and deposition and the radiative effects of aerosol particles that causes uncertainty in their representation within GCMs. The aim of this study was to perturb aspects of a sulfur cycle scheme used within a GCM to represent the climatological impacts of sulfate aerosol derived from natural and anthropogenic sulfur sources. It was found that perturbing volcanic SO2 emissions and the scavenging rate of SO2 by precipitation had the largest influence on the sulfate burden. When these parameters were perturbed the sulfate burden ranged from 0.73 to 1.17 TgS for 2050 sulfur emissions (A2 Special Report on Emissions Scenarios (SRES)), comparable with the range in sulfate burden across all the Intergovernmental Panel on Climate Change SRESs. Thus, the results here suggest that the range in sulfate burden due to model uncertainty is comparable with scenario uncertainty. Despite the large range in sulfate burden there was little influence on the climate sensitivity, which had a range of less than 0.5 K across the ensemble. We hypothesize that this small effect was partly associated with high sulfate loadings in the control phase of the experiment.

Microbial perchlorate reduction: A precise laboratory determination of the chlorine isotope fractionation and its possible biochemical basis

Perchlorate-reducing bacteria fractionate chlorine stable isotopes giving a powerful approach to monitor the extent of microbial consumption of perchlorate in contaminated sites undergoing remediation or natural perchlorate containing sites. This study reports the full experimental data and methodology used to re-evaluate the chlorine isotope fractionation of perchlorate reduction in duplicate culture experiments of Azospira suillum strain PS at 37 degrees C (Delta Cl-37(Cr)--ClO4-) previously reported, without a supporting data set by Coleman et al. [Coleman, M.L., Ader, M., Chaudhuri, S., Coates,J.D., 2003. Microbial Isotopic Fractionation of Perchlorate Chlorine. Appl. Environ. Microbiol. 69, 4997-5000] in a reconnaissance study, with the goal of increasing the accuracy and precision of the isotopic fractionation determination. The method fully described here for the first time, allows the determination of a higher precision Delta Cl-37(Cl)--ClO4- value, either from accumulated chloride content and isotopic composition or from the residual perchlorate content and isotopic composition. The result sets agree perfectly, within error, giving average Delta Cl-37(Cl)--ClO4- = -14.94 +/- 0.15%omicron. Complementary use of chloride and perchlorate data allowed the identification and rejection of poor quality data by applying mass and isotopic balance checks. This precise Delta Cl-37(Cl)--ClO4-, value can serve as a reference point for comparison with future in situ or microcosm studies but we also note its similarity to the theoretical equilibrium isotopic fractionation between a hypothetical chlorine species of redox state +6 and perchlorate at 37 degrees C and suggest that the first electron transfer during perchlorate reduction may occur at isotopic equilibrium between art enzyme-bound chlorine and perchlorate. (C) 2008 Elsevier B.V. All rights reserved.

Accumulated metal speciation in earthworm populations with multi-generational exposure to metalliferous soils: cell fractionation and high energy synchrotron analyses

Predicting metal bioaccumulation and toxicity in soil organisms is complicated by site-specific biotic and abiotic parameters. In this study we exploited tissue fractionation and digestion techniques, combined with X-ray absorption spectroscopy (XAS), to investigate the whole-body and subcellular distributions, ligand affinities, and coordination chemistry of accumulated Pb and Zn in field populations of the epigeic earthworm Lumbricus rubellus inhabiting three contrasting metalliferous and two unpolluted soils. Our main findings were (i) earthworms were resident in soils with concentrations of Pb and Zn ranging from 1200 to 27 000 mg kg(-1) and 200 to 34 000 mg kg(-1), respectively; (ii) Pb and Zn primarily accumulated in the posterior alimentary canal in nonsoluble subcellular fractions of earthworms; (iii) site-specific differences in the tissue and subcellular partitioning profiles of populations were observed, with earthworms from a calcareous site partitioning proportionally more Pb to their anterior body segments and Zn to the chloragosome-rich subcellular fraction than their acidic-soil inhabiting counterparts; (iv) XAS indicated that the interpopulation differences in metal partitioning between organs were not accompanied by qualitative differences in ligand-binding speciation, because crystalline phosphate-containing pyromorphite was a predominant chemical species in the whole-worm tissues of all mine soil residents. Differences in metal (Pb, Zn) partitioning at both organ and cellular levels displayed by field populations with protracted histories of metal exposures may reflect their innate ecophysiological responses to essential edaphic variables, such as Ca2+ status. These observations are highly significant in the challenging exercise of interpreting holistic biomarker data delivered by "omic" technologies.

Microbial isotopic fractionation of perchlorate chlorine

Perchlorate contamination can be microbially respired to innocuous chloride and thus can be treated effectively. However, monitoring a bioremediative strategy is often difficult due to the complexities of environmental samples. Here we demonstrate that microbial respiration of perchlorate results in a significant fractionation (similar to - 15parts per thousand) of the chlorine stable isotope composition of perchlorate. This can be used to quantify the extent of biotic degradation and to separate biotic from abiotic attenuation of this contaminant.

The effect of aqueous diffusion on the fractionation of chlorine and bromine stable isotopes

Diffusive isotopic fractionation factors are important in order to understand natural processes and have practical application in radioactive waste storage and carbon dioxide sequestration. We determined the isotope fractionation factors and the effective diffusion coefficients of chloride and bromide ions during aqueous diffusion in polyacrylamide gel. Diffusion was determined as functions of temperature, time and concentration. The effect of temperature is relatively large on the diffusion coefficient (D) but only small on isotope fractionation. For chlorine, the ratio, D-35cl/D-37cl varied from 1.00128 +/- 0.00017 (1 sigma) at 2 degrees C to 1.00192 +/- 0.00015 at 80 degrees C. For bromine, D-79Br/D-81Br varied from 1.00098 +/- 0.00009 at 2 degrees C to 1.0064 +/- 0.00013 at 21 degrees C and 1.00078 +/- 0.00018 (1 sigma) at 80 degrees C. There were no significant effects on the isotope fractionation due to concentration. The lack of sensitivity of the diffusive isotope fractionation to anything at the most common temperatures (0 to 30 C) makes it particularly valuable for application to understanding processes in geological environments and an important natural tracer in order to understand fluid transport processes. (C) 2009 Elsevier Ltd. All rights reserved.

Differentiating bone osteonal turnover rates by density fractionation; validation using the bomb C-14 atmospheric pulse

The density (BSG) of bone increases, at the osteon scale, during lifetime aging within the bone. In addition, post-mortem diagenetic change due to microbial attack produces denser bioapatite. Thus, fractionation of finely powdered bone on the basis of density should not only enable younger and older populations of osteons to be separated but also make it possible to separate out a less diagenetically altered component. We show that the density fractionation method can be used as a tool to investigate the isotopic history within an individual's lifetime, both in recent and archaeological contexts, and we use the bomb C-14 atmospheric pulse for validating the method.

Metal bioaccumulation and cellular fractionation in an epigeic earthworm (Lumbricus rubellus): the interactive influences of population exposure histories, site-specific geochemistry and mitochondrial genotype

Subcellular fractionation techniques were used to describe temporal changes (at intervals from T0 to T70 days) in the Pb, Zn and P partitioning profiles of Lumbricus rubellus populations from one calcareous (MDH) and one acidic (MCS) geographically isolated Pb/Zn-mine sites and one reference site (CPF). MDH and MCS individuals were laboratory maintained on their native field soils; CPF worms were exposed to both MDH and MCS soils. Site-specific differences in metal partitioning were found: notably, the putatively metal-adapted populations, MDH and MCS, preferentially partitioned higher proportions of their accumulated tissue metal burdens into insoluble CaPO4-rich organelles compared with naive counterparts, CPF. Thus, it is plausible that efficient metal immobilization is a phenotypic trait characterising metal tolerant ecotypes. Mitochondrial cytochrome oxidase II (COII) genotyping revealed that the populations indigenous to mine and reference soils belong to distinct genetic lineages, differentiated by 13%, with 7 haplotypes within the reference site lineage but fewer (3 and 4, respectively) in the lineage common to the two mine sites. Collectively, these observations raise the possibility that site-related genotype differences could influence the toxico-availability of metals and, thus, represent a potential confounding variable in field-based eco-toxicological assessments.

Homogeneous and heterogeneous reactions of atmospheric mercury(II) with sulfur(IV)

Atmospheric models suggest that the reduction of Hg(II) to Hg(O) by S(W) prolongs the residence time of mercury. The redox reaction was investigated both in the aqueous phase (where the reductant is sulfite) and on particulate matter (where the reductant in SO2(g)). In both cases, one of the ultimate products is HgS. A mechanism is proposed involving formation of Hg(O) followed by mercury-induced disproportionation of SO2.

The adsorption and stability of sulfur containing amino acids on Cu{531}

The adsorption of L-CySteine and L-methionine amino acids on a chiral Cu{5 3 1} surface was investigated with high resolution X-ray photoelectron spectroscopy (XPS) and carbon K-edge near edge X-ray absorption fine structure (NEXAFS) Spectroscopy using synchrotron radiation. XPS shows that at 300 K L-cysteine adsorbs through two oxygen, a nitrogen and a sulfur atom, in a four point 'quadrangular footprint', whereas L-methionine adsorbs through only two oxygen and a nitrogen atom in a 'triangular footprint'. NEWS was used to clarify the adsorption geometry of both molecules, which suggests a binding orientation to the top layer and second layer atoms in two different orientations associated with adsorption sites on {1 1 0} and {3 1 1} microfacets; of the Cu{5 3 1} surface. (C) 2009 Elsevier B.V. All rights reserved.

Thermal Fractionation and isothermal crystallization of polyethylene nanocomposites prepared by in situ polymerization

Nanocomposites of high-density polyethylene (HDPE) and carbon nanotubes (CNT) of different geometries (single wall, double wall, and multiwall; SWNT, DWNT, and MWNT) were prepared by in situ polymerization of ethylene on CNT whose surface had been previously treated with a metallocene catalytic system. In this work, we have studied the effects of applying the successive self-nucleation and annealing thermal fractionation technique (SSA) to the nanocomposites and have also determined the influence of composition and type of CNT on the isothermal crystallization behavior of the HDPE. SSA results indicate that all types of CNT induce the formation of a population of thicker lamellar crystals that melt at higher temperatures as compared to the crystals formed in neat HDPE prepared under the same catalytic and polymerization conditions and subjected to the same SSA treatment. Furthermore, the peculiar morphology induced by the CNT on the HDPE matrix allows the resolution of thermal fractionation to be much better. The isothermal crystallization results indicated that the strong nucleation effect caused by CNT reduced the supercooling needed for crystallization. The interaction between the HDPE chains and the surface of the CNT is probably very strong as judged by the results obtained, even though it is only physical in nature. When the total crystallinity achieved during isothermal crystallization is considered as a function of CNT content, it was found that a competition between nucleation and topological confinement could account for the results. At low CNT content the crystallinity increases (because of the nucleating effect of CNT on HDPE), however, at higher CNT content there is a dramatic reduction in crystallinity reflecting the increased confinement experienced by the HDPE chains at the interfaces which are extremely large in these nanocomposites. Another consequence of these strong interactions is the remarkable decrease in Avrami index as CNT content increases. When the Avrami index reduces to I or lower, nucleation dominates the overall kinetics as a consequence of confinement effects. Wide-angle X-ray experiments were performed at a high-energy synchrotron source and demonstrated that no change in the orthorhombic unit cell of HDPE occurred during crystallization with or without CNT.