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101.
Micelle formation between 5-hydroxytryptamine and adenosine triphosphate in platelet storage organelles 总被引:8,自引:0,他引:8
As judged by analytical ultracentrifugation, 5-hydroxytryptamine and adenosine-5'-triphosphate form micelles in artificial mixtures and also in storage organelles containing 5-hydroxytryptamine of blood platelets of rabbits. Their average apparent molecular weights depend on the concentration and on the molar ratio of the two constituents. The 5-hydroxytryptamine and adenosine triphosphate of these 5-hydroxytryptamine organelles may be stored in vivo together as micelles with apparent molecular weights of several hundred thousands or more. 相似文献
102.
Cohen-Cory S 《Science (New York, N.Y.)》2002,298(5594):770-776
Synapse formation and stabilization in the vertebrate central nervous system is a dynamic process, requiring bi-directional communication between pre- and postsynaptic partners. Numerous mechanisms coordinate where and when synapses are made in the developing brain. This review discusses cellular and activity-dependent mechanisms that control the development of synaptic connectivity. 相似文献
103.
Sancho JV Pozo OJ Zamora T Grimalt S Hernández F 《Journal of agricultural and food chemistry》2003,51(15):4202-4206
A rapid and sensitive liquid chromatography/electrospray ionization/tandem mass spectrometry (LC-ESI-MS-MS) method has been developed for the determination of the plant growth regulator paclobutrazol in pear samples. Extraction was performed with methanol by using a high-speed blender Ultra-Turrax, and 10 microL of pear extract was directly injected in the LC-ESI-MS-MS system without any previous sample treatment. The highest sensitivity of the method was achieved under MS-MS conditions obtaining a limit of detection of 0.7 microg/kg and a quantification limit of 5 microg/kg, with a run time of only 5.5 min. Recoveries for paclobutrazol from spiked pear samples at 0.005, 0.05, and 0.5 mg/kg were around 82-102% with relative standard deviations between 2 and 7%. The method was applied to real treated and untreated samples of pears, using quality control samples as a evaluation of the method reliability. Two MS-MS transitions were selected, one for quantification (294 > 70) and the other for confirmation of the analyte (296 > 70). All the experiments were performed in compliance with good laboratory practices. 相似文献
104.
Fernández-Cruz ML Villarroya M Llanos S Alonso-Prados JL García-Baudín JM 《Journal of agricultural and food chemistry》2004,52(4):860-863
Field trials have been carried out to determine the variability of residue levels of fenitrothion and its main metabolites fenitrothion-oxon and 3-methyl-4-nitrophenol in individual kaki fruits versus composite samples, in peel versus flesh, and in whole uncooked versus whole cooked fruits. Residue levels have been determined by gas chromatography with thermionic specific detection after extraction with ethyl acetate and without further cleanup. At harvest, residue levels of fenitrothion were below maximum residue levels (MRLs) and the two metabolites 3-methyl-4-nitrophenol and fenitrothion-oxon could be quantified with average amounts of 0.080 and 0.012 mg/kg, respectively. Levels of fenitrothion decreased 88% after peeling, whereas temperature did not result in a high variation. The ratios of the highest residue level in the individual fruits to the corresponding mean of residue levels in the composite samples for fenitrothion were <3. This value is lower than that recommended by the World Health Organization as default value for consumer risk assessment. 相似文献
105.
Svetaz L Tapia A López SN Furlán RL Petenatti E Pioli R Schmeda-Hirschmann G Zacchino SA 《Journal of agricultural and food chemistry》2004,52(11):3297-3300
The crude methanolic extract of Zuccagnia punctata was active toward the fungal pathogens of soybean Phomopsis longicolla and Colletotrichum truncatum. Assay guided fractionation led to the isolation of two chalcones, one flavanone and a new caffeoyl ester derivative as the compounds responsible for the antifungal activity. Another new caffeoyl ester derivative was isolated from the antifungal chloroform extract but proved to be inactive against the soybean infecting fungi up to 50 microg/mL 相似文献
106.
Assessment of the volatile composition of juices of apricot, peach, and pear according to two pectolytic treatments 总被引:1,自引:0,他引:1
Riu-Aumatell M López-Tamames E Buxaderas S 《Journal of agricultural and food chemistry》2005,53(20):7837-7843
The behavior of volatile compounds according to two enzymatic treatments applied during the manufacture of fruit juice is described. More than 80 compounds were detected of a wide range of chemical families (alcohols, aldehydes, ketones, terpenoids, esters, norisoprenoids, ...). Theaspirane and alpha-isophoron were tentatively identified for the first time in apricot and peach fruits. The enzymes used, for extraction or clarification of fruit juices, modified the polysaccharides separated by molecular weight and the content of soluble polysaccharides. This could indicate differences in the fruit juice matrix, which could be related to observed changes in the volatile profile. In apricot, the enzymes enhanced the juice in terpenes and norisoprenoids as varietal compounds. In peach and pear, the enzymes used did not favor the amount of lactones and decadienoate esters, the character impact compounds, respectively. 相似文献
107.
Vichi S Riu-Aumatell M Mora-Pons M Buxaderas S López-Tamames E 《Journal of agricultural and food chemistry》2005,53(26):10154-10160
A HS-SPME method coupled to GC-MS was developed and applied for the qualitative and semiquantitative characterization of distilled gin volatile fraction. Sampling, chromatographic conditions, and method performances were evaluated, and the developed method was applied as a comparative study of some of the most popular commercial London Dry Gins and other gins with geographic denominations. During this study, 70 components of the gins' volatile fraction were isolated, tentatively identified or identified by reference compounds. They were mainly represented by mono- and sesquiterpenic compounds, which were quantitatively determined. The comparative study of London Dry Gins and gins with geographical indication permitted clear differentiation between the gins with geographical indication and one of the London Dry Gins tested. 相似文献
108.
109.
Björn Thrandur Björnsson Viktoria Johansson Susana Benedet Ingibjörg Eir Einarsdottir Jon Hildahl Thorleifur Agustsson Elisabeth Jönsson 《Fish physiology and biochemistry》2002,27(3-4):227-242
The focus of this review is on the regulatory mechanisms and the mode of action of GH in salmonids. To stimulate further research, it aims at highlighting areas where numerous important breakthroughs have recently been made, as well as where data are currently lacking. The regulation of GH secretion is under complex hypothalamic control, as well as under negative feedback control by GH and IGF-I. Further, the recently characterized ghrelin is a potent GH secretagogue, and may prove to be a link between feed intake and growth regulation. GH plasma profiles show indications of diurnal changes, but whether salmonids have true pulsatile GH secretion remains to be elucidated. The recent cloning and characterization of the salmon GH receptor (GHR) is a major research break-through which will give new insights into the mechanisms of GH action. It should also stimulate research into circulating GH-binding proteins (GHBPs), as they appear to be a soluble form of the GHR. The salmonid GHR sequences show evolutionary divergence from other fish species, but with a high degree of identity within the salmonid group. Radioreceptorassay studies have found GHR present in all tissues examined, which is in line with the highly pleiotropic action of GH. Data are currently scarce on the plasma dynamics of GH in salmonids, and further studies on GHR and GHBPs dynamics coupled to assessments of GH clearance rates and pathways are needed. The direct versus indirect nature of GH action remains to be clarified, but GH appears to act both locally at the target tissue level to stimulate the autocrine/paracrine action of IGF-I, as well as on the liver to increase plasma IGF-I levels. In addition, GH interacts with other hormones such as cortisol, thyroid hormones, insulin, and reproductive hormones, generating a wide range of physiological effects. GH may act both peripherally and directly at the level of the central nervous system to modify behavior, probably by altering the dopaminergic activity in the brain. 相似文献
110.
Francine Kershaw Will McClintock Kimberly R. Andrews Federico G. Riet-Sapriza Susana Caballero Michael J. Tetley Giuseppe Notarbartolo di Sciara Erich Hoyt Grace Goldberg Emily Chou Kelsey Kane-Ritsch Howard C. Rosenbaum 《水产资源保护:海洋与淡水生态系统》2021,31(9):2440-2458
- The protection of evolutionary processes and maintenance of genetic diversity is necessary for the persistence of biodiversity and ecosystem resilience. The importance of genetic diversity has been reflected in a range of marine policy mechanisms, and the genetic ‘toolbox’ has great potential to support marine protection and marine spatial planning (MSP) at multiple scales. Despite scientific advances in the application of genetics in marine protection and management, systematic integration of genetic information has been generally lacking, primarily due to a knowledge and communication disconnect between geneticists and the marine policy and management community.
- To meet these outstanding needs, a ‘geospatial genetics’ approach to spatially map species-specific genetic data and associated information in a way that can be readily integrated by practitioners into marine protection and MSP decisions was developed. Techniques to derive geospatial genetic data layers, which can be viewed and mapped alongside other kinds of spatial data commonly used by conservation practitioners, hold promise for increasing the accessibility of genetic data to support policy decisions more fully.
- While applicable to many mobile and sessile taxa, an initial focus was placed on marine mammals, and the approach was developed and refined through a series of international meetings and published papers, as well as the development of interactive, expert-reviewed case studies hosted on the MSP tool SeaSketch.
- Outcomes of the work to date are currently serving in the policy arena by informing the identification of Important Marine Mammal Areas, an initiative led by the IUCN Marine Mammal Protected Areas Task Force to apply criteria to identify marine mammal habitats across the world's ocean, seas and relevant inland waters through a standardized process.
- It has become clear that geospatial genetics has great potential to foster increased collaboration among an intersectional community of geneticists, spatial ecologists, and practitioners. This increased opportunity for dialogue and cooperation will help ensure that evolutionary processes are factored into marine protection and MSP processes, and potentially for freshwater and terrestrial systems.