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Full-Text Articles in Life Sciences
Effect Of Caffeine Supplementation On Vertical Jump Performance, Heart Rate Variability, And Electromyography, Collin T. Garner
Effect Of Caffeine Supplementation On Vertical Jump Performance, Heart Rate Variability, And Electromyography, Collin T. Garner
Masters Theses
Research into caffeine’s ability to improve anaerobic performance is inconclusive. Eleven anaerobically trained individuals (mean age: 23.45 ± 1.51 years) participated in this study. Assessments of resting heart rate variability (HRV), exercise heart rate variability, surface electromyography (sEMG), static vertical jump (SJ), and countermovement vertical jump (CMJ) were conducted before and after administration of placebo and caffeinated treatments. Three trials of each vertical jump technique were performed before and after treatment administration. A 60-minute absorption period was utilized for absorption of the treatment following its ingestion. All participants performed testing on two separate occasions, once under the placebo condition and …
Evolution Of Caffeine Biosynthetic Enzymes And Pathways In Flowering Plants, Ruiqi Huang
Evolution Of Caffeine Biosynthetic Enzymes And Pathways In Flowering Plants, Ruiqi Huang
Dissertations
Convergent evolution generally refers to the independent evolution of similar biological function more than once in unrelated species. Caffeine is thought to have evolved by convergence, and is naturally produced through secondary metabolism in plants to defend against pathogen attack and insect feeding or to attract pollinators. The same caffeine biosynthetic pathway has been elucidated in Camellia (tea) and Coffea (coffee), in which xanthosine is sequentially methylated to caffeine via 7-methylxanthine and theobromine. However, although the same catalysis pathway is used, different (paralogous) enzymes in the SAMT/BAMT/theobromine synthase (SABATH) multigene family are used in the two species. In my dissertation, …
Evolutionary Convergence Of The Caffeine Biosynthetic Pathway In Chocolate Followed Duplication Of A Constrained Ancestral Enzyme, Andrew J. O'Donnell
Evolutionary Convergence Of The Caffeine Biosynthetic Pathway In Chocolate Followed Duplication Of A Constrained Ancestral Enzyme, Andrew J. O'Donnell
Masters Theses
Caffeine biosynthesis is widely distributed in flowering plants and requires three consecutive methylation steps of xanthine alkaloids. Genes that have previously been reported to participate in the multi-step pathway in Coffea sp. (coffee) and Camellia sinensis (tea) encode members of the SABATH family of methyltransferases. Two genes highly expressed in fruits of Theobroma cacao (cacao) are orthologous to the caffeine genes in tea and appear to have diversified following gene duplication. Biochemical characterization of the enzymes (XMTs) encoded by these genes strongly suggest an unprecedented major pathway to theobromine, a precursor to caffeine. These findings imply that caffeine biosynthesis evolved …