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41.
Eveland SS Milot DP Guo Q Chen Y Hyland SA Peterson LB Jezequel-Sur S O'Donnell GT Zuck PD Ferrer M Strulovici B Wagner JA Tanaka WK Hilliard DA Laterza O Wright SD Sparrow CP Anderson MS 《Analytical biochemistry》2007,368(2):239-249
Cholesteryl ester transfer protein (CETP) is a serum component responsible for both cholesteryl ester and triglyceride trafficking between high-density lipoprotein (HDL) and the apolipoprotein B (apoB)-containing very low-density lipoprotein (VLDL) and low-density lipoprotein (LDL). Several fluorescence-based assays that monitor these transfers have been reported, but to date such assays have suffered from a low signal/background (S/B) ratio and have been described for use only in relatively purified in vitro systems. We have modified the more advanced of these assays to incorporate a noninterfering, nondiffusable fluorescence quencher into previously described cosonicate particles, often referred to as microemulsions. This simple improvement resulted in particles that had an average threefold enhanced S/B window over particles without quenchers but that continued to show the essential properties of a catalytic assay, including catalysis to a single endpoint, excellent linearity with protein and particle concentration, and an appropriate sensitivity to inhibition. This reduced assay noise allowed the subsequent development of protocols for the direct measure of cholesteryl ester (CE) transfer activity resident in human and animal serum as well as the development of 384- and 3456-well screening protocols with good precision and accuracy. Thus, by expanding the dynamic response window of the assay, we have created an assay generalizable to many settings. 相似文献
42.
Francisco Ruiz José Borrego Manuel Abad Berta Carro Joaquín Rodríguez-Vidal Maria Isabel Prudêncio 《Geobios》2007,40(5):689
Integrated analysis of a 50-m long sedimentary core collected in the central part of the Odiel estuary (SW Atlantic coast of Spain) allows delineation of the main paleoenvironmental changes that occurred in this area during the Holocene. Eight sedimentary facies were deposited in the last ca. 9000 years BP, confirming a transgressive-regressive cycle that involves the transition from fluvial to salt marsh deposits with intermediate marine tidal deposits. A storm event is detected at ca. 5705 14C years BP (mean calibrated age) with distinct lithostratigraphical, textural, geochemical, and palaeontological features. 相似文献
43.
Berta Algueró Enrique Pedroso Vicente Marchán Anna Grandas 《Journal of biological inorganic chemistry》2007,12(6):901-911
Platinated oligonucleotides are promising tools for the control of gene expression, since they may target and cross-link nucleic
acid chains. Here we describe a method for the preparation of platinated oligonucleotides that has proved able to selectively
cross-link complementary sequences, making use of 5-methylcytidine analogs with thioether or imidazole groups attached to
the 4-position. These nucleoside analogs were derivatized as phosphoramidites and introduced in oligonucleotide chains using
standard phosphite triester chemistry. Different oligonucleotide sequences containing either one or two analogs appending
from the 5′-end were synthesized and used in preliminary platination studies. The reaction of transplatin with oligonucleotides
containing the thioether-modified nucleobase was fast, but generally afforded unstable adducts and complex reaction mixtures.
The imidazole-containing oligonucleotides reacted with transplatin much more slowly, in particular at slightly basic pH, and
it was found that the imidazole-modified cytosine was less reactive than the natural nucleobases. In contrast, transplatin
selectively reacted with the thioether and imidazole groups of oligonucleotides containing the two cytosine analogs in neighboring
positions, even in the presence of the four nucleobases and particularly three guanines, affording platinated oligonucleotides
suitable for cross-linking.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
44.
Albert Calbet Mireia Bertos Claudio Fuentes-Grünewald Elisabet Alacid Rosa Figueroa Berta Renom Esther Garcés 《Harmful algae》2011,10(6):654-667
We isolated eleven strains of the harmful algal bloom (HAB)-forming dinoflagellate Karlodinium veneficum during a bloom event in the NW Mediterranean coastal waters and we studied the inter-strain variability in several of their physiological and biochemical traits. These included autotrophic growth parameters, feeding capabilities (mixotrophy), lipid composition, and, in some cases, their responses to biotic and abiotic factors. The strains were found to differ in their growth rates (0.27–0.53 d−1) and in the maximum cell concentrations achieved during stationary phase (6.1 × 104–8.6 × 104 cells mL−1). Their ingestion performance, when offered Rhodomonas salina as prey, was also diverse (0.22–1.3 cells per K. veneficum per day; 8–52% of their daily ration). At least two strains survived for several months under strict heterotrophic conditions (no light, low inorganic nutrients availability, and R. salina as food source). These strains also showed very distinct fatty acid compositions, with very low contents of monounsaturated and polyunsaturated fatty acids. According to a Bray Curtis similarity analysis, three or four strain groups able to perform different roles in bloom development were identified. We further analyzed one strain from each of the two most distinct groups with respect to prey concentration, light intensity, nutrient availability, and we determined the functional responses (growth and feeding rates) to food concentration. Taken together, the results served to highlight the role of mixotrophy and clone variability in the formation of HABs. 相似文献
45.
The cellular prion protein (PrP(C)) plays a fundamental role in prion disease. PrP(C) is a glycosylphosphatidylinositol (GPI)-anchored protein with two variably occupied N-glycosylation sites. In general, GPI-anchor and N-glycosylation direct proteins to apical membranes in polarized cells whereas the majority of mouse PrP(C) is found in basolateral membranes in polarized Madin-Darby canine kidney (MDCK) cells. In this study we have mutated the first, the second, and both N-glycosylation sites of PrP(C) and also replaced the GPI-anchor of PrP(C) by the Thy-1 GPI-anchor in order to investigate the role of these signals in sorting of PrP(C) in MDCK cells. Cell surface biotinylation experiments and confocal microscopy showed that lack of one N-linked oligosaccharide leads to loss of polarized sorting of PrP(C). Exchange of the PrP(C) GPI-anchor for the one of Thy-1 redirects PrP(C) to the apical membrane. In conclusion, both N-glycosylation and GPI-anchor act on polarized sorting of PrP(C), with the GPI-anchor being dominant over N-glycans. 相似文献
46.
47.
Eunice Areal Bacelar José M. Moutinho-Pereira Berta C. Gon?alves Jo?o I. Lopes Carlos M. Correia 《Acta Physiologiae Plantarum》2009,31(3):611-621
Gas exchange rates, chlorophyll fluorescence, pressure–volume relationships, photosynthetic pigments, total soluble sugars,
starch, soluble proteins and proline concentrations were investigated in five Olea europaea L. cultivars with different geographical origins (Arbequina, Blanqueta, Cobran?osa, Manzanilla and Negrinha) grown under
Mediterranean field conditions. We found considerable genotypic differences among the cultivars. Comparing the diurnal gas
exchange rates, we observed that Cobran?osa, Manzanilla and Negrinha had high photosynthetic rate than Arbequina and Blanqueta.
The first group reveals to be better acclimated to drought conditions, and appears to employ a prodigal water-use strategy,
whereas Blanqueta and Arbequina, with high water-use efficiency, appear to employ a conservative water-use strategy. The degree
of midday depression in photosynthesis was genotype dependent, with a maximum in Arbequina and a minimum in Negrinha. The
reductions in the photosynthetic rate were dependent from both stomatal and non-stomatal limitations. Elastic adjustment plays an important role as drought tolerance mechanism. The group of cultivars that employ a prodigal
water-use strategy revealed high tissue elasticity, whereas Arbequina and Blanqueta revealed high tissue rigidity. We also
identified the existence of drought tolerance mechanisms associated with soluble proteins accumulation in the foliage. The
high levels of soluble proteins in Arbequina may represent an increased activity of oxidative stress defence enzymes and may
also represent a reserve for post stress recovery. In all cultivars, especially in Manzanilla, free proline was accumulated
in the foliage. The discussed aspects of drought stress metabolism may have an adaptative meaning, supporting the hypothesis
that olive cultivars native to dry regions, such as Cobran?osa, Manzanilla and Negrinha, have more capability to acclimate
to drought conditions than cultivars originated in regions with a more temperate climate, like Arbequina and Blanqueta. 相似文献
48.
McCulloch CC Kay DM Factor SA Samii A Nutt JG Higgins DS Griffith A Roberts JW Leis BC Montimurro JS Zabetian CP Payami H 《Human genetics》2008,123(3):257-265
The objective of this study was to explore combined effects of four candidate susceptibility genes and two exposures on Parkinson’s
disease (PD) risk; namely, α-synuclein (SNCA) promoter polymorphism REP1, microtubule-associated protein tau (MAPT) H1/H2 haplotypes, apolipoprotein E (APOE) ε2/ε3/ε4 polymorphism, ubiquitin carboxy-terminal esterase L1 (UCHL1) S18Y variant, cigarette smoking and caffeinated coffee consumption. 932 PD patients and 664 control subjects from the NeuroGenetics
Research Consortium, with complete data on all six factors, were studied. Uniform protocols were used for diagnosis, recruitment,
data collection and genotyping. A logistic regression model which included gene-exposure interactions was applied. Likelihood
ratio tests (LRTs) were used for significance testing and Bayesian inference was used to estimate odds ratios (ORs). MAPT (P = 0.007), SNCA REP1 (P = 0.012), smoking (P = 0.001), and coffee (P = 0.011) were associated with PD risk. Two novel interactions were detected: APOE with coffee (P = 0.005), and REP1 with smoking (P = 0.021). While the individual main effects were modest, each yielding OR < 1.6, the effects were cumulative, with some combinations
reaching OR = 12.6 (95% CI: 5.9–26.8). This study provides evidence for the long-held notion that PD risk is modulated by
cumulative and interactive effects of genes and exposures. Furthermore, the study demonstrates that while interaction studies
are useful for exploring risk relationships that might otherwise go undetected, results should be interpreted with caution
because of the inherent loss of power due to multiple testing. The novel findings of this study that warrant replication are
the evidence for interaction of coffee with APOE, and of smoking with REP1 on PD risk.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
49.
Raffaella Balestrini Graziella Berta Paola Bonfante 《Biology of the cell / under the auspices of the European Cell Biology Organization》1992,75(3):235-243
Summary— Positional and structural modifications were demonstrated in nuclei of leek cells, after establishment of a symbiosis with two vesicular-arbuscular fungi, Glomus versiforme and Glomus E3. By combining light, immuno-electron microscopy and morphometry, the fungi were shown to have a direct effect on the host nuclear morphology: the effect was confined to a specific plant tissue (the cortical parenchyma) and to a moment of the fungal morphogenesis (the arbuscule). When they branch to form the complex structures called arbuscules in the inner parenchyma cells, the host nucleus migrates from the periphery of these cells towards their centre. In addition, it becomes larger and lobed, with a decondensed chromatin. A monoclonal antibody that mostly binds to the condensed chromatin revealed a significant decrease in gold labelling intensity over the nuclei of the colonized cells. These modifications suggest that the nuclear migration and the changes in chromatin organization are related to the modifications in gene expression observed during the establishment of mycorrhizal symbiosis. 相似文献
50.
Carbon export from arbuscular mycorrhizal roots involves the translocation of carbohydrate as well as lipid 总被引:4,自引:0,他引:4
Bago B Pfeffer PE Abubaker J Jun J Allen JW Brouillette J Douds DD Lammers PJ Shachar-Hill Y 《Plant physiology》2003,131(3):1496-1507
Arbuscular mycorrhizal (AM) fungi take up photosynthetically fixed carbon from plant roots and translocate it to their external mycelium. Previous experiments have shown that fungal lipid synthesized from carbohydrate in the root is one form of exported carbon. In this study, an analysis of the labeling in storage and structural carbohydrates after (13)C(1) glucose was provided to AM roots shows that this is not the only pathway for the flow of carbon from the intraradical to the extraradical mycelium (ERM). Labeling patterns in glycogen, chitin, and trehalose during the development of the symbiosis are consistent with a significant flux of exported glycogen. The identification, among expressed genes, of putative sequences for glycogen synthase, glycogen branching enzyme, chitin synthase, and for the first enzyme in chitin synthesis (glutamine fructose-6-phosphate aminotransferase) is reported. The results of quantifying glycogen synthase gene expression within mycorrhizal roots, germinating spores, and ERM are consistent with labeling observations using (13)C-labeled acetate and glycerol, both of which indicate that glycogen is synthesized by the fungus in germinating spores and during symbiosis. Implications of the labeling analyses and gene sequences for the regulation of carbohydrate metabolism are discussed, and a 4-fold role for glycogen in the AM symbiosis is proposed: sequestration of hexose taken from the host, long-term storage in spores, translocation from intraradical mycelium to ERM, and buffering of intracellular hexose levels throughout the life cycle. 相似文献