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Burkepile Deron E. Adam Thomas C. Roycroft Madelyn Ladd Mark C. Munsterman Katrina S. Ruttenberg Benjamin I. 《Coral reefs (Online)》2019,38(3):417-423
Coral Reefs - Parrotfishes are key herbivores on Caribbean reefs but also feed on other benthic taxa such as corals and sponges. Here, we used in situ behavioral observations to show that Caribbean... 相似文献
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Assembly and immunological properties of Newcastle disease virus-like particles containing the respiratory syncytial virus F and G proteins 总被引:1,自引:0,他引:1
McGinnes LW Gravel KA Finberg RW Kurt-Jones EA Massare MJ Smith G Schmidt MR Morrison TG 《Journal of virology》2011,85(1):366-377
Human respiratory syncytial virus (RSV) is a serious respiratory pathogen in infants and young children as well as elderly and immunocompromised populations. However, no RSV vaccines are available. We have explored the potential of virus-like particles (VLPs) as an RSV vaccine candidate. VLPs composed entirely of RSV proteins were produced at levels inadequate for their preparation as immunogens. However, VLPs composed of the Newcastle disease virus (NDV) nucleocapsid and membrane proteins and chimera proteins containing the ectodomains of RSV F and G proteins fused to the transmembrane and cytoplasmic domains of NDV F and HN proteins, respectively, were quantitatively prepared from avian cells. Immunization of mice with these VLPs, without adjuvant, stimulated robust, anti-RSV F and G protein antibody responses. IgG2a/IgG1 ratios were very high, suggesting predominantly T(H)1 responses. In contrast to infectious RSV immunization, neutralization antibody titers were robust and stable for 4 months. Immunization with a single dose of VLPs resulted in the complete protection of mice from RSV replication in lungs. Upon RSV intranasal challenge of VLP-immunized mice, no enhanced lung pathology was observed, in contrast to the pathology observed in mice immunized with formalin-inactivated RSV. These results suggest that these VLPs are effective RSV vaccines in mice, in contrast to other nonreplicating RSV vaccine candidates. 相似文献
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Serotonin (5HT) synthesis in brain is influenced by precursor (tryptophan (TRP)) concentrations, which are modified by food
ingestion. Hence, in rats, a carbohydrate meal raises brain TRP and 5HT; a protein-containing meal does not, but little attention
has focused on differences among dietary proteins. Recently, single meals containing different proteins have been shown to
produce marked changes in TRP and 5HT. The present studies evaluate if such differences persist when rats ingest such diets
chronically. Male rats were studied that ingested diets for 9 days containing zein, wheat gluten, soy protein, casein, or
α-lactalbumin (17% dry weight). Brain TRP varied up to eightfold, and 5HT synthesis fivefold among the different protein groups.
TYR and LEU concentrations, and catecholamine synthesis rate in brain varied much less. The effects of dietary protein on
brain TRP and 5HT previously noted after single meals thus continue undiminished when such diets are consumed chronically. 相似文献
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Acute caffeine injection (100 mg/kg) elevates brain levels of tryptophan (TRP), serotonin (5HT), and 5-hydroxyindoleacetic acid (5HIAA). Experiments were performed to determine if the increases in 5HT and 5HIAA result from a stimulation of the rate of 5HT synthesis. Both the rate of 5-hydroxytryptophan (5HTP) accumulation following NSD-1015 injection, and the rate of 3H-5-hydroxyindole synthesis from 3H-tryptophan were measured following caffeine administration and found to be normal. Tryptophan hydroxylase activity, as measured in brain homogenates, was also unaffected by caffeine. The results suggest that the elevations in brain 5HT and 5HIAA levels produced by caffeine do reflect enhanced 5HT synthesis, despite significant elevations in brain TRP level. Some other mechanism(s) must therefore be responsible for these elevations in brain 5-hydroxyindole levels. 相似文献
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The dipeptide aspartame (APM; aspartylphenylalanine methylester), an artificial sweetener, was studied for its ability to influence brain levels of the large neutral amino acids and the rates of hydroxylation of the aromatic amino acids. The administration by gavage of APM (200 mg/kg) caused large increments in blood and brain levels of phenylalanine and tyrosine by 60 minutes. Brain tryptophan level was occasionally reduced significantly, but the brain levels of the branched-chain amino acids were always unaffected. Smaller doses (50, 100 mg/kg) also raised blood and brain tyrosine and phenylalanine, but did not reduce brain tryptophan levels. At the highest dose (200 mg/kg), APM gavage caused an insignificant increase in dopa accumulation (after NSD-1015), and a modest reduction in 5-hydroxytryptophan accumulation. No changes in the brain levels of serotonin, 5-hydroxyindoleacetic acid, dopamine, dihydroxyphenylacetic acid, homovanillic acid, or norepinephrine were produced by APM administration (200 mg/kg). These results thus indicate that APM, even when administered in amounts that cause large increments in brain tyrosine and phenylalanine, produce minimal effects on the rates of formation of monoamine transmitters. 相似文献
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The mixing zone between Cayuga Lake, N.Y. and one of its tributaries, Salmon Creek, was studied to determine effects of physical processes such as adsorption, precipitation or sedimentation on phosphorus discharged by the Creek. A high sodium concentration in the lake served as a natural tracer, by which proportions of Creek and Lake water were determined at any point in the mixing zone. Proportions of Creek and Lake water were used to predict amounts of P that would be expected on the basis of mixing alone. Differences between predicted and observed concentrations were attributed to local physical processes. This analysis showed that, in several of the six plumes surveyed, there was substantial loss of P due to sedimentation. The P-distribution in all plumes showed evidence of exchanges between particles and the medium, as a result of which soluble reactive-P usually decreased and soluble unreactive-P usually increased. The nature and magnitude of these local processes were such that they could have significant effects on the fate of stream-P discharged into the lake.Supported in part by Office and Technology, U.S. Department Interior and by Hatch Funds from U.S. Department of Agriculture. 相似文献
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SuJean Choi Briana DiSilvio Madelyn H. Fernstrom John D. Fernstrom 《Amino acids》2013,45(5):1133-1142
Exercise raises brain serotonin release and is postulated to cause fatigue in athletes; ingestion of branched-chain amino acids (BCAA), by competitively inhibiting tryptophan transport into brain, lowers brain tryptophan uptake and serotonin synthesis and release in rats, and reputedly in humans prevents exercise-induced increases in serotonin and fatigue. This latter effect in humans is disputed. But BCAA also competitively inhibit tyrosine uptake into brain, and thus catecholamine synthesis and release. Since increasing brain catecholamines enhances physical performance, BCAA ingestion could lower catecholamines, reduce performance and thus negate any serotonin-linked benefit. We therefore examined in rats whether BCAA would reduce both brain tryptophan and tyrosine concentrations and serotonin and catecholamine synthesis. Sedentary and exercising rats received BCAA or vehicle orally; tryptophan and tyrosine concentrations and serotonin and catecholamine synthesis rates were measured 1 h later in brain. BCAA reduced brain tryptophan and tyrosine concentrations, and serotonin and catecholamine synthesis. These reductions in tyrosine concentrations and catecholamine synthesis, but not tryptophan or serotonin synthesis, could be prevented by co-administering tyrosine with BCAA. Complete essential amino acid mixtures, used to maintain or build muscle mass, were also studied, and produced different effects on brain tryptophan and tyrosine concentrations and serotonin and catecholamine synthesis. Since pharmacologically increasing brain catecholamine function improves physical performance, the finding that BCAA reduce catecholamine synthesis may explain why this treatment does not enhance physical performance in humans, despite reducing serotonin synthesis. If so, adding tyrosine to BCAA supplements might allow a positive action on performance to emerge. 相似文献
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