Genetic variation in nitrogen metabolism in Mytilus edulis: contribution of the Lap locus
Hilbish, T.J.; Koehn, R.K. (1985). Genetic variation in nitrogen metabolism in Mytilus edulis: contribution of the Lap locus, in: Gibbs, P.E. (Ed.) Proceedings of the 19th European Marine Biology Symposium, Plymouth, Devon, UK, 16-21 September 1984. pp. 497-503 In: Gibbs, P.E. (Ed.) (1985). Proceedings of the Nineteenth European Marine Biology Symposium, Plymouth, Devon, UK, 16-21 September 1984. European Marine Biology Symposia, 19. Cambridge University Press: Cambridge. ISBN 0-521-30294-3. 541 pp., more In: European Marine Biology Symposia., more |
| Abstract | Aminopeptidase-I (AM-I) is the enzyme product of the genetically-polymorphic locus Lap, AM-I hydrolyzes the cleavage of a terminal amino acid from small polypeptides that result from lysosomal degradation of protein, We have previously shown that genetic variation in the biochemical properties of allozymes of AM-I result in genotype-dependent rates of cell volume regulation during salinity adaptation, During hypoosmotic stress, genotypes with the Lap94 allele excrete ammonia and amino acids at rates nearly twice that of alternate genotypes. We propose that differential nitrogen excretion may be the physiological consequence of this polymorphism that results in selection against the Lap94 allele in natural populations of Mytilus edulis L., in Long Island Sound. A test of this hypothesis was conducted by examining the rates of nitrogen excretion in natural populations under ambient conditions, Animals were taken from Long Island Sound to the laboratory and their rates of ammonia and amine excretion determined within 24 h. The rates of both ammonia and amino acid excretion were found to be genotype-dependent and in the direction predicted ; Lap94 genotypes excreted 26,4 nmol/h and alternate genotypes excreted 13,9 nmol/h (values for a 0,02 g standard animal), Over a 4-week period these rates of excretion represent 9,8% and 5,2% respectively, of the individual's body nitrogen and therefore comprise a significant proportion of the individual's nitrogen metabolism. |
|
