Meeting Abstract

13.1  Friday, Jan. 4  Differential energy allocation for protein synthesis is genetically determined during marine larval development LEE, J.W.*; APPLEBAUM, S.L.; MANAHAN, D.T.; Univ. Southern California, Los Angeles

Many studies have demonstrated that physiological processes change in response to environmental perturbations. Less is known, however, about the genetic bases that might establish physiological potentials for adaptation. Genetically-determined variation in metabolic efficiency will likely impact the energetic scope for stress responses. The energetic requirement of protein synthesis is a major component of metabolism and has been reported to have a fixed cost in specific stages of animal development. We measured the cost of protein synthesis in larvae of a bivalve (Crassostrea gigas). Phenotypic contrasts in metabolic allocation to protein synthesis were studied at different temperatures and for different genotypes using crosses of pedigreed families. In wild-type "control" larvae, approximately 60% of available metabolic energy was allocated to protein synthesis. This metabolic allocation varied in contrasting phenotypes. In slower-growing larvae, up to 80% of metabolic rate was allocated to protein synthesis. In faster-growing larvae, this value was 2-fold lower, decreasing to ~40% of metabolic rate. The effect of environmental variation on metabolic allocation to protein synthesis was studied. Variation in temperature differentially changed rates (Q10) of respiration relative to protein synthesis. This differential response resulted in a lower percent of metabolic rate being accounted for by protein synthesis at lower temperatures. The capacity to respond to environmental stress is likely related to metabolic efficiency. Defining the genetic bases of metabolic allocation has implications for understanding the role of genotype-dependent responses to changing environmental conditions.