972 resultados para Bioactive constituents
Resumo:
Purpose : Despite increased interest in quality of life (QOL) as an outcome measure and as a means of identifying client needs in health care, its conceptualisation and the identification of its constituents have been poorly researched for elderly people with stroke in Hong Kong. Method: This article analysed the literature to identify components relevant to the QOL of Chinese elderly people with stroke living in the community in Hong Kong. Results : While common components of QOL for elderly people with and without stroke and regardless of cultural background were identified, a number were specific to an elderly Chinese stroke population. Conclusion : Recommendations for future research have been made with reference to further exploring and validating these components for the target population. A clear understanding of these aspects is essential for the development of sensitive QOL measures to guide and evaluate service delivery to this population.
Resumo:
Tracking the reaction history is the means of choice to identify bioactive compounds in large combinatorial libraries. The authors describe two approaches to synthesis on silica beads: a) addition of a reporter dye tag during each synthesis step (see Figure), which attaches itself to the bead by colloidal forces, and b) encapsulating arrays of fluorescent dyes into the beads to encode them uniquely, for recognition with a flow cytometer after each reaction step.
Resumo:
Spiroacetals, cryptic ketodiols showing a hydroxyl group at both sides of a carbonyl whithin reachable distances are very widespread in nature. A group of 30 different structures, not including stereoisomers, represent volatile, less polar constituents of insect secretions. Five different systems were identified: 1,6-dioxaspirol[4.4]nonanes, 1,6-dioxaspiro[4.5]decanes, 1,6-dioxaspiro[4.6]undecanes, 1,7-dioxaspiro[5.5] undecanes, and 1,7-dioxaspiro[5.6]dodecanes. Some spiroacetals are insect pheromones: (2S,5R)-2-ethyl-1,6-dioxaspiro[4.4]nonane, chalcogran, 1, is a key component of the male produced aggregation pheromone of the spruce bark beetle, Pityogenes cha2cographus. In contrast, (5S,7S)-7-methyl-1,6-dioxaspiro[4.5]decane, 2, conophthorin, acts as a repellent or spacer in several bark beetles. Racemic 1,7-diosaspiro[5.5]undecane, olean, 5, is the female produced sex pheromone of the olive fly, Bactrocera (Dacus) oleae. The most widespread spiroacetal is 2,8-dimethyl-1,7-dioxaspiro[5.5]undecane, 8. Tt often forms a mixture of (E,E)- and (E,Z)-isomers, the (E,E)-isomer showing (2S,6R,8S)-configuration. In the solitary bee, Andrena wilkella, it serves as an aggregation pheromone. Present knowledge on structures and distribution of volatile spiroacetals is comprehensively compiled. Stereochemical aspects and mass spectrometric fragmentation patterns are discussed in detail to facilitate identifications of hitherto unknown compounds. Synthetic approaches to spiroacetals are classified and reviewed. Last but not least, facts and speculations on the biosynthesis of volatile spiroacetals are presented.
Resumo:
Pecans from the cultivars Wichita and Western Schley [Carya illinoinensis (Wangenh.) K. Koch] collected over three years were analyzed for the following constituents: total lipid content; fatty acid profiles; sucrose content; protein; total dietary fiber; the minerals magnesium, calcium, potassium, sulfur, phosphorus, boron, copper, iron, manganese, sodium, zinc, and aluminum; vitamin C; and lipase; and lipoxygenase activities. Year of harvest and cultivar had little effect on the composition of the pecans. Overall, protein content was the only constituent that differed between pecans grown in Australia and those grown in the United States. This difference is probably related to differences in growing location and horticultural practices between the two countries.
Resumo:
Marine viruses have been shown to affect phytoplankton productivity; however, there are no reports on the effect of viruses on benthic microalgae (microphytobenthos). Hence, this study investigated the effects of elevated concentrations of virus-like particles on the photosynthetic physiology and community composition of benthic microalgae and phytoplankton. Virus populations were collected near the sediment surface and concentrated by tangential flow ultrafiltration, and the concentrate was added to benthic and water column samples that were obtained along a eutrophication gradient in the Brisbane River/Moreton Bay estuary, Australia. Photosynthetic and community responses of benthic microalgae, phytoplankton and bacteria were monitored over 7 d in aquaria and in situ. Benthic microalgal communities responded to viral enrichment in both eutrophic and oligotrophic sediments. In eutrophic sediments, Euglenophytes (Euglena sp.) and bacteria decreased in abundance by 20 to 60 and 26 to 66%, respectively, from seawater controls. In oligotrophic sediments, bacteria decreased in abundance by 30 to 42% from seawater controls but the dinoflagellate Gymnodinium sp. increased in abundance by 270 to 3600% from seawater controls, The increased abundance of Gymnodinium sp. may be related to increased availability of dissolved organic matter released from lysed bacteria. Increased (140 to 190% from seawater controls) initial chlorophyll a fluorescence measured with a pulse-amplitude modulated fluorometer was observed in eutrophic benthic microalgal incubations following virus enrichment, consistent with photosystem II damage. Virus enrichment in oligotrophic water significantly stimulated carbon fixation rates, perhaps due to increased nutrient availability by bacterial lysis. The interpretation of data from virus amendment experiments is difficult due to potential interaction with unidentified bioactive compounds within seawater concentrates. However, these results show that viruses are capable of influencing microbial dynamics in sediments.
Resumo:
Flotillin-1 was recently shown to be enriched on detergent-resistant domains of the plasma membrane called lipid rafts. These rafts, enriched in sphingolipids and cholesterol, sequester certain proteins while excluding others. Lipid rafts have been implicated in numerous cellular processes including signal transduction, membrane trafficking and molecular sorting. In this study, we demonstrate both morphologically and biochemically that lipid rafts are present on phagosomes, These structures are enriched in flotillin-1 and devoid of the main phagosomes membrane protein lysosomal-associated membrane protein (LAMP1), The flotillin-1 present on phagosomes does not originate from the plasma membrane during phagocytosis but accumulates gradually on maturing phagosomes, Treatment with bafilomycin A1, a compound that inhibits the proton pump ATPase and prevents the fusion of phagosomes with late endocytic organelles, prevents the acquisition of flotillin-1 by phagosomes, indicating that this protein might be recruited on phagosomes from endosomal organelles. A proteomic characterization of the lipid rafts of phagosomes indicates that actin, the alpha- and beta -subunits of heterotrimeric G proteins, as well as subunits of the proton pump V-ATPase are among the constituents of these domains. Remarkably, the intracellular parasite Leishmania donovani can actively inhibit the acquisition of flotillin-1-enriched lipid rafts by phagosomes and the maturation of these organelles. These results indicate that specialized functions required for phagolysosome biogenesis may occur at focal points on the phagosome membrane, and therefore represent a potential target of intracellular pathogens.
Resumo:
Eucalyptus savannas on low nutrient soils are being extensively cleared in Queensland. In this paper we provide background information relevant to understanding nutrient (particularly nitrogen) dynamics in sub/tropical savanna, and review the available evidence relevant to understanding the potential impact of clearing Eucalyptus savanna on nutrient relations. The limited evidence presently available can be used to argue for the extreme positions that: (i) woody vegetation competes with grasses Cor resources. and tree/shrub clearing improves pasture production, (ii) woody vegetation benefits pasture production. At present, the lack of fundamental knowledge about Australian savanna nutrient relations makes accurate predictions about medium- and long-term effects of clearing on nutrient relations in low nutrient savannas difficult. The future of cleared savannas will differ if herbaceous species maintain all functions that woody vegetation has previously held, or if woody species have functions distinct from those of herbaceous vegetation. Research suggests that savanna soils are susceptible to nitrate leaching, and that trees improve the nutrient status of savanna soils in some situations. The nitrogen capital of cleared savanna is at risk if mobile ions are not captured efficiently by the vegetation. and nitrogen input via N-2 fixation from vegetation and microbiotic crusts is reduced. In order to predict clearing effects on savanna nutrient relations, research should be directed to answering (i) how open or closed nutrient cycles are in natural and cleared savanna, (ii) which functions are performed by savanna constituents such as woody and herbaceous vegetation, native and exotic plant species. termites, and microbiotic 7 crusts in relation to nutrient cycles. In the absence of detailed knowledge about savanna functioning, clearing carries the risk of promoting continuous nutrient depiction.
Resumo:
We examine the potential impact of interconnectivity of value chain partnerships through electronic means (e-business practices) on the management of Public Sector Agriculture R&D in Australia. We review the changing forms of managing research and development, the forces driving these changes, and R&D processes that are theoretically consistent with the move towards value chain involvement and the increase in active constituents in Public Sector Agriculture R&D. We then explore the potential of emerging e-business models to change the patterns of inter-connectivity, speed and omnipresence of partners in the value chain. Three e-business R&D management practices are identified that provide the prerequisite flexibility necessary to take advantage of opportunistic markets. These R&D business practices are: compressing R&D to reduce time to market, fostering co-development to enter a market at the last moment and building flexible products that allow adjustment at the last possible moment. Some fundamental reallocation of existing resources will be required to meet these markets. Implications of these e-business practices for R&D management are discussed.
Resumo:
A well-preserved palynoflora is reported from within a cored interval of a coal-exploratory borehole (1-UN-23-PI of the Geological Survey of Brazil) in the southern part of the Parnaiba Basin, northeastern Brazil. The sample studied is from the lower portion of the Piaui Formation. Its palynoflora is characterized by particular abundance of the trilete cavate/pseudosaccate miospores Spelaeotriletes triangulus Neves and Owens, 1966 and S. arenaceus Neves and Owens, 1966, together with cingulizonate forms mainly attributable to Vallatisporites Hacquebard, 1957 and Cristatisporites R. Potonie and Kremp emend. Butterworth et al., 1964. Radially and bilaterally symmetrical monosaccate pollen grains are also well-represented, chiefly by Plicatipollenites Lele, 1964 and Potonieisporites Bhardwaj, 1954, respectively. Taeniate grains (i.e., monosaccates and bisaccates) are relatively minor constituents of the palynoflora; no marine microplankton were encountered. Several species are described in detail : the trilete apiculate spores Brevitriletes levis (Balme and Hennelly) Bharadwaj and Srivastava, 1969 and Horriditriletes uruguaiensis (Marques-Toigo) Archangelsky and Gamerro, 1979; and the taeniate pollen grains Meristocorpus ostentus sp. nov. and Lahirites segmentatus sp. nov. A Pennsylvanian (Late Carboniferous : late Westphalian) age is adduced for the palynoflora via its correlation with part of the Tapajos Group (specifically, the upper Itaituba Formation) of the Amazonas Basin in northern Brazil. The entirely land-derived palynomorphs, associated with abundant plant debris, corroborate previous suggestions that the lower part of the Piaui Formation accumulated in a nonmarine setting under conditions of aridity.
Resumo:
Human R183H-GH causes autosomal dominant GH deficiency type II. Because we show here that the mutant hormone is fully bioactive, we have sought to locate an impairment in its progress through the secretory pathway as assessed by pulse chase experiments. Newly synthesized wild-type and R183H-GH were stable when expressed transiently in AtT20 cells, and both formed equivalent amounts of Lubrol-insoluble aggregates within 40 min after synthesis. There was no evidence for intermolecular disulfide bond formation in aggregates of wild-type hormone or the R183H mutant. Both wildtype and R183H-GH were packaged into secretory granules, assessed by the ability of 1 mm BaCl2 to stimulate release and by immunocytochemistry. The mutant differed from wildtype hormone in its retention in the cells after packaging into secretory granules; 50% more R183H-GH than wild-type aggregates were retained in AtT20 cells 120 min after synthesis, and stimulated release of R183H-GH or a mixture of R183H-GH and wild-type that had been retained in the cell was reduced. The longer retention of R183H-GH aggregates indicates that a single point mutation in a protein contained in secretory granules affects the rate of secretory granule release.
Resumo:
Purpose: This study aimed to identify the constituents and conceptual characteristics of the quality of life (QOL) of Chinese elderly stroke survivors. living in the community in Hong Kong. Method: A triangulated approach was used to identify the QOL components for this population. This process involved a comparison of QOL components gathered from three different methods, namely, focus group interviews, review of the literature and the contents of the generic Hong Kong Chinese version of the World Health Organization Quality of Life Scale (CWHOQOL-HK). Five health professionals were involved in the comparison process. A percentage of inter-judge agreement was used to determine the reliability of the comparisons made between the judges. Results: This study identified 36 components considered to contribute to the QOL of Chinese elderly stroke survivors in Hona Kong. The conceptual characteristics of their QOL generally concurred with those identified in the literature. Conclusion: Both similarities and differences were found in the QOL components identified in this study when compared to those identified in studies of Western populations who are elderly and had a stroke. The contents of the CWHOQOL-HK scale were found to lack adequacy in representing the QOL of Chinese elderly stroke survivors in Hong Kong. Recommendations are given, based on the findings of this study, to overcome this limitation for its application as a QOL measure for this population.
Resumo:
Four novel sesquiterpenes, namely 7alpha,8beta,13-trihydroxy-5,13-marasmanolide (2), isoplorantinone (5), 4,8,14-trihydroxyilludala-2,6,8-triene (6), and 8-hydroxy-8,9-secolactara-1,6-dien-5,13-olide (10), together with six known ones, 7alpha,8beta-dihydroxy-5,13-marasmanolide (1), 7alpha,8alpha-dihydroxy-5,13-marasmanolide (3), isolactarorufin (4), blennin A (7), blennin D (8), and lactarorufin (9), were isolated from the ethanolic extract of Lactarius piperatus. The structures of these sesquiterpenes, representing diversified structural types, were determined mainly by spectroscopic methods, especially 2D-NMR techniques. The structure of 6 was further confirmed by a single-crystal X-ray-diffraction determination.
Resumo:
We report a 5 year old girl with postnatal overgrowth (height velocity >97th centile), hyperinsulinaemia, and increased insulin-like growth factor 1 for age, without evidence of bioactive or immunoreactive growth hormone excess or pituitary abnormality. Although her overgrowth may be a result of hyperinsulinism, her serum contains a factor (neither insulin nor IGF-1) which is able to stimulate the proliferation of lymphocyte precursors, and this could also account for the overgrowth. Over the course of two years observation she has developed acanthosis nigricans and diabetes mellitus.
Resumo:
This paper presents a comprehensive study of sludge floc characteristics and their impact on compressibility and settleability of activated sludge in full scale wastewater treatment processes. The sludge flocs were characterised by morphological (floc size distribution, fractal dimension, filament index), physical (flocculating ability, viscosity, hydrophobicity and surface charge) and chemical (polymeric constituents and metal content) parameters. Compressibility and settleability were defined in terms of the sludge volume index (SVI) and zone settling velocity (ZSV). The floc morphological and physical properties had important influence on the sludge compressibility and settleability. Sludges containing large flocs and high quantities of filaments, corresponding to lower values of fractal dimension (D-f), demonstrated poor compressibility and settleability. Sludge flocs with high flocculating ability had lower SVI and higher ZSV, whereas high values of hydrophobicity, negative surface charge and viscosity of the sludge flocs correlated to high SVI and low ZSV. The quantity of the polymeric compounds protein. humic substances and carbohydrate in the sludge and the extracted extracellular polymeric substances (EPS) had significant positive correlations with SVI. The ZSV was quantitatively independent of the polymeric constituents. High concentrations of the extracted EPS were related to poor compressibility and settleability. The cationic ions Ca, Mg, Al and Fe in the sludge improved significantly the sludge compressibility and settleability. (C) 2003 Elsevier Science B.V. All rights reserved.
Resumo:
Activated sludge floes are a flocculated mass of microorganisms, extracellular polymeric substances (EPS) and adsorbed organic and inorganic material. The structure of the floes is very heterogeneous and floes with very different properties and morphologies may occur, depending on the conditions in the activated sludge treatment plant and wastewater composition. Present thinking suggests that cations, such as calcium, create cationic bridges with EPS excreted by the bacteria and thereby hold the various floe constituents together. However, due to the complex and heterogeneous nature of activated sludge, the mechanisms have neither been thoroughly investigated nor successfully quantified. A better understanding and description of the biological flocculation process is necessary in order to establish more efficient operational strategies. The main aim of this study was to get a comprehensive and unique insight into the floe properties of activated sludge and to assess the relative impact of chemical and physical parameters. A variety of sludges from full scale treatment plants with different settling properties were characterised. The interrelationships between floe parameters such as composition of EPS, surface properties and floe structure, and their effect on the flocculation and separation properties were assessed. The results indicate that the EPS, both in terms of quantity and quality, are very important for the floe properties of the activated sludge. However, presence of filaments may alter the physical properties of the floes considerably. The EPS showed positive correlations to sludge volume index (SVI) if only sludges with low or moderate numbers of filaments were included. The surface properties were more affected by the composition of the EPS than by the number of filaments. The EPS showed positive correlation to negative surface charge and a negative correlation to relative hydrophobicity and flocculation ability. The negative correlation between flocculation ability and amount of EPS was surprising. The shear sensitivity, measured as degree of erosion of floes when subjected to shear, was more affected by floe size and number of filaments than amount of EPS.