Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P50583 (asymmetrical)
 12,197 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Deletion or inhibition of myostatin in mammals has been demonstrated to markedly increase muscle mass by hyperplasia, hypertrophy, or a combination of both. Despite a remarkably high degree of conservation with the mammalian protein, the function of myostatin remains unknown in fish, many species of which continue muscle growth throughout the lifecycle by hyperplasia. Transgenic rainbow trout (Oncorhynchus mykiss) overexpressing follistatin, one of the more efficacious antagonists of myostatin, were produced to investigate the effect of this protein on muscle development and growth. P(1) transgenics overexpressing follistatin in muscle tissue exhibited increased epaxial and hypaxial muscling similar to that observed in double-muscled cattle and myostatin null mice. The hypaxial muscling generated a phenotype reminiscent of well-developed rectus abdominus and intercostal muscles in humans and was dubbed "six pack." Body conformation of the transgenic animals was markedly altered, as measured by condition factor, and total muscle surface area increased. The increased muscling was due almost exclusively to hyperplasia as evidenced by a higher number of fibers per unit area and increases in the percentage of smaller fibers and the number of total fibers. In several individuals, asymmetrical muscling was observed, but no changes in mobility or behavior of follistatin fish were observed. The findings indicate that overexpression of follistatin in trout, a species with indeterminate growth rate, enhances muscle growth. It remains to be determined whether the double muscling in trout is due to inhibition of myostatin, other growth factors, or both.
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PMID:Overexpression of follistatin in trout stimulates increased muscling. 1947 87

The abundant centre hypothesis (ACH) assumes that population abundance, population size, density and per-capita reproductive output should peak at the centre of a species' geographic range and decline towards the periphery. Increased isolation among and decreased reproductive output within edge populations should reduce within-population genetic diversity and increase genetic differentiation among edge relative to central populations. The ACH also predicts asymmetrical gene flow, with net movement of migrants from the centre to edges. We evaluated these ecological assumptions and population-genetic predictions in the endemic flowering plant Leavenworthia stylosa. Although populations were more spatially isolated near range edges, the geographic centre was surrounded by and not coincident with areas of peak population abundance, and plant density increased towards range edges. Per-capita seed number was not associated with distance to the range centre, but seed number/m(2) increased near range edges. In support of ACH predictions, allelic diversity at 12 microsatellite loci declined with distance from the range centre, and pairwise FST values were higher between edge populations than between central populations. Coalescent analyses confirmed that gene flow was most infrequent between edge populations, but there was not an asymmetric pattern of gene flow predicted by the ACH. This study shows that among-population demographic variability largely did not support the ACH, while patterns of genetic diversity, differentiation and gene flow were generally consistent with its predictions. Such mixed support has frequently been observed in tests of the ACH and raises concerns regarding the generality of this hypothesis for species range limits.
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PMID:Demographic and population-genetic tests provide mixed support for the abundant centre hypothesis in the endemic plant Leavenworthia stylosa. 2335 49