92 research outputs found

    A critical appraisal of appendage disparity and homology in fishes

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    Fishes are both extremely diverse and morphologically disparate. Part of this disparity can be observed in the numerous possible fin configurations that may differ in terms of the number of fins as well as fin shapes, sizes and relative positions on the body. Here, we thoroughly review the major patterns of disparity in fin configurations for each major group of fishes and discuss how median and paired fin homologies have been interpreted over time. When taking into account the entire span of fish diversity, including both extant and fossil taxa, the disparity in fin morphologies greatly complicates inferring homologies for individual fins. Given the phylogenetic scope of this review, structural and topological criteria appear to be the most useful indicators of fin identity. We further suggest that it may be advantageous to consider some of these fin homologies as nested within the larger framework of homologous fin‐forming morphogenetic fields. We also discuss scenarios of appendage evolution and suggest that modularity may have played a key role in appendage disparification. Fin modules re‐expressed within the boundaries of fin‐forming fields could explain how some fins may have evolved numerous times independently in separate lineages (e.g., adipose fin), or how new fins may have evolved over time (e.g., anterior and posterior dorsal fins, pectoral and pelvic fins). We favour an evolutionary scenario whereby median appendages appeared from a unique field of competence first positioned throughout the dorsal and ventral midlines, which was then redeployed laterally leading to paired appendages.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/151971/1/faf12402_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/151971/2/faf12402.pd

    Hydrophobic plant antioxidants. Preparation of nanoparticles and their application for prevention of neurodegenerative diseases. Review and experimental data.

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    There are numerous reports on the role of oxidative stress in the origin of some neurodegenerative (Alzheimer's and Parkinson's) diseases; however, the information concerning molecular mechanisms of the observed effects is rather contradictory. This paper summarizes the review of our own works in this field and new experimental observations on the antioxidant action of some hydrophobic plant compounds. We discuss our hypothesis on the role of misfolded proteins in the regulation of the chaperone system involved in the genesis of amyloid neurodegenerative (prion and Alzheimer's) diseases, briefly describe the role of modification of the glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase in the inhibition of glycolysis and induction of the apoptosis of nerve cells, and suggest possible ways of the use of hydrophobic plant antioxidants for the prevention of amyloid transformation of proteins and other neurodegenerative processes

    Antioxidant and prooxidant effects of quercetin on glyceraldehyde-3-phosphate dehydrogenase

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    Anti- and prooxidant properties of quercetin under different conditions were investigated using glyceraldehyde-3-phosphate dehydrogenase, a glycolytic enzyme containing essential cysteine residues. Quercetin was shown to produce hydrogen peroxide in aqueous solutions at pH 7.5, this resulting in the oxidation of the cysteine residues of the enzyme. Quercetin significantly increased oxidation of GAPDH observed in the presence of ferrous ions, particularly when FeSO(4) was added to the solution containing GAPDH and quercetin. The results suggest the formation of hydroxyl radical in the case of the addition of FeSO(4) to a quercetin solution. At the same time, quercetin protects GAPDH from oxidation in the presence of ascorbate and Fe(3+). In the absence of metals, quercetin protects SH-groups of GAPDH from oxidation by the superoxide anion generated by the system containing xanthine/xanthine oxidase
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