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排序方式: 共有419条查询结果,搜索用时 15 毫秒
81.
Ghourab S Beale KE Semjonous NM Simpson KA Martin NM Ghatei MA Bloom SR Smith KL 《Regulatory peptides》2011,172(1-3):8-15
Vasoactive intestinal peptide (VIP) is a 28 amino acid peptide expressed throughout the peripheral and central nervous systems. VIP and the VIP receptor VPAC(2)R are expressed in hypothalamic nuclei involved in the regulation of energy homeostasis. VIP has been shown to be involved in the regulation of energy balance in a number of non-mammalian vertebrates. We therefore examined the effects of intracerebroventricular (ICV) administration of VIP on food intake, energy expenditure and activity in adult male Wistar rats. VIP administration caused a potent short lived decrease in food intake and an increase in activity and energy expenditure. The pathways potentially involved in the anorexigenic effects of VIP were investigated by measuring the release of neuropeptides involved in the regulation of food intake from hypothalamic explants treated with VIP. VIP significantly stimulated the release of the anorexigenic peptide alpha-melanocyte stimulating hormone (αMSH). These studies suggest that VIP may have an endogenous role in the hypothalamic control of energy homeostasis. 相似文献
82.
M Cilli E Gelen S Yildiz T Saglam MH Camur 《Biology of sport / Institute of Sport》2014,31(4):277-282
This study aimed to investigate the kinematic and kinetic changes when resistance is applied in horizontal and vertical directions, produced by using different percentages of body weight, caused by jumping movements during a dynamic warm-up. The group of subjects consisted of 35 voluntary male athletes (19 basketball and 16 volleyball players; age: 23.4 ± 1.4 years, training experience: 9.6 ± 2.7 years; height: 177.2 ± 5.7 cm, body weight: 69.9 ± 6.9 kg) studying Physical Education, who had a jump training background and who were training for 2 hours, on 4 days in a week. A dynamic warm-up protocol containing seven specific resistance movements with specific resistance corresponding to different percentages of body weight (2%, 4%, 6%, 8%, 10%) was applied randomly on non consecutive days. Effects of different warm-up protocols were assessed by pre-/post- exercise changes in jump height in the countermovement jump (CMJ) and the squat jump (SJ) measured using a force platform and changes in hip and knee joint angles at the end of the eccentric phase measured using a video camera. A significant increase in jump height was observed in the dynamic resistance warm-up conducted with different percentages of body weight (p < 0.05). On the other hand, no significant difference in different percentages of body weight states was observed (p > 0.05). In jump movements before and after the warm-up, while no significant difference between the vertical ground reaction forces applied by athletes was observed (p > 0.05), in some cases of resistance, a significant reduction was observed in hip and knee joint angles (p < 0.05). The dynamic resistance warm-up method was found to cause changes in the kinematics of jumping movements, as well as an increase in jump height values. As a result, dynamic warm-up exercises could be applicable in cases of resistance corresponding to 6-10% of body weight applied in horizontal and vertical directions in order to increase the jump performance acutely. 相似文献
83.
Many populations of migratory songbirds are declining or shifting in distribution. This is likely due to environmental changes that alter factors such as food availability that may have an impact on survival and/or breeding success. We tested the impact of experimentally supplemented food on the breeding success over three years of northern wheatears (Oenanthe oenanthe), a species in decline over much of Europe. The number of offspring fledged over the season was higher for food-supplemented birds than for control birds. The mechanisms for this effect were that food supplementation advanced breeding date, which, together with increased resources, allowed further breeding attempts. While food supplementation did not increase the clutch size, hatching success or number of chicks fledged per breeding attempt, it did increase chick size in one year of the study. The increased breeding success was greater for males than females; males could attempt to rear simultaneous broods with multiple females as well as attempting second broods, whereas females could only increase their breeding effort via second broods. Multiple brooding is rare in the study population, but this study demonstrates the potential for changes in food availability to affect wheatear breeding productivity, primarily via phenotypic flexibility in the number of breeding attempts. Our results have implications for our understanding of how wheatears may respond to natural changes in food availability due to climate changes or changes in habitat management. 相似文献
84.
Motivation
Paired-end sequencing protocols, offered by next generation sequencing (NGS) platforms like Illumia, generate a pair of reads for every DNA fragment in a sample. Although this protocol has been utilized for several metagenomics studies, most taxonomic binning approaches classify each of the reads (forming a pair), independently. The present work explores some simple but effective strategies of utilizing pairing-information of Illumina short reads for improving the accuracy of taxonomic binning of metagenomic datasets. The strategies proposed can be used in conjunction with all genres of existing binning methods.Results
Validation results suggest that employment of these “Binpairs” strategies can provide significant improvements in the binning outcome. The quality of the taxonomic assignments thus obtained are often comparable to those that can only be achieved with relatively longer reads obtained using other NGS platforms (such as Roche).Availability
An implementation of the proposed strategies of utilizing pairing information is freely available for academic users at https://metagenomics.atc.tcs.com/binning/binpairs. 相似文献85.
Separate physiological roles and subcellular compartments for two tetrapyrrole biosynthetic pathways in Euglena gracilis 总被引:13,自引:0,他引:13
delta-Aminolevulinic acid (ALA), the first committed precursor to the tetrapyrrole components of hemes and chlorophylls, is synthesized by two different routes in the photosynthetic phytoflagellate Euglena gracilis: directly from glutamate, mediated by a 5-carbon pathway, and via condensation of glycine and succinyl-CoA, catalyzed by the enzyme ALA synthase. The physiological roles of the two pathways were determined by administration of specifically 14C-labeled ALA precursors to cultures growing under different physiological conditions. Relative activities of the ALA synthase and 5-carbon pathways were monitored by incorporation of radioactivity from [2-14C] glycine and [1-14C]glutamate into highly purified protoheme, heme a and chlorophyll a derivatives. Wild type cells grown photoautotrophically or photoheterotrophically synthesized chlorophyll and incorporated radioactivity from [1-14C]glutamate into the tetrapyrrole nucleus of the pigment. [2-14C]Glycine was incorporated primarily into the nontetrapyrrole-derived portions of chlorophyll. In the same cultures both [2-14C]glycine and [1-14C]glutamate were efficiently incorporated into protoheme, while only [2-14C] glycine was incorporated into heme a. In dark-grown wild type or light-grown aplastidic cells, no chlorophyll was formed, and both protoheme and heme a were labeled exclusively from [2-14C]glycine. These results indicate: (a) ALA synthase and the 5-carbon pathway operate simultaneously in growing green cells; (b) the 5-carbon pathway provides ALA for chloroplast protoheme and chlorophyll, and is associated with chloroplast development; (c) ALA synthase provides ALA only for nonplastid heme biosynthesis; and (d) the two ALA pathways are separately compartmentalized along with complete sets of enzymes for subsequent tetrapyrrole synthesis from each ALA pool. The protoheme that was synthesized from [1-14C] glutamate had a higher specific radioactivity than chlorophyll synthesized from the same precursor. This result together with calculated specific radioactivities of the products synthesized during the incubation period, suggest that both protoheme and heme a undergo metabolic turnover. 相似文献
86.
Induction of delta-Aminolevulinic Acid Synthase Activity and Inhibition of Heme Synthesis in Euglena gracilis by N-Methyl Mesoporphyrin IX
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N-Methyl mesoporphyrin IX, an inhibitor of heme synthesis, increases extractable δ-aminolevulinic acid (ALA) synthase activity when administered to growing cultures of Euglena gracilis Klebs strain Z Pringsheim in micromolar concentrations. Wild-type light-grown green cells and white aplastidic cells exhibited 2.8-fold and 1.8-fold increases, respectively, in ALA synthase activity within five to six hours after incubation with 4 × 10−6 molar N-methyl mesoporphyrin IX. Protoheme levels were decreased and 59Fe incorporation into heme was inhibited by N-methyl mesoporphyrin IX, indicating that, as in animal cells, N-methyl mesoporphyrin IX acts specifically to block iron insertion into protoporphyrin IX. Chlorophyll synthesis in wild-type cells was not affected within the first 6 hours after administration of N-methyl mesoporphyrin IX. 相似文献
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Joanne Durgan Alf H. Lystad Katherine Sloan Sven R. Carlsson Michael I. Wilson Elena Marcassa Rachel Ulferts Judith Webster Andrea F. Lopez-Clavijo Michael J. Wakelam Rupert Beale Anne Simonsen David Oxley Oliver Florey 《Molecular cell》2021,81(9):2031-2040.e8
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90.