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Rates of respiration and protein synthesis were measured during embryonic and larval development of Antarctic asteroids with
different life-history modes (non-feeding and feeding larvae: Acodontaster hodgsoni, Porania antarctica, Odontaster meridionalis). Patterns of respiration for these species all show an increase during embryogenesis, with subsequent maintenance of routine
respiration (“starvation resistance”), even in the absence of food for ~4 months (O. meridionalis). Fractional rates of protein synthesis (i.e., rate per unit mass of whole-body protein content) in the Antarctic larvae
are essentially identical to those of temperate species. Larvae of O. meridionalis had an average fractional synthesis rate of 0.52% ± 0.05 h−1 at −1.0°C, which is comparable to the temperate asteroid Asterina miniata at 0.53% ± 0.14 h−1 at 15°C. For embryos of the asteroids A. hodgsoni and P. antarctica, fractional rates of protein synthesis (~0.2% h−1) also are comparable to those reported for embryos of temperate echinoderm species. While rates of synthesis are high, rates
of protein deposition are relatively low (percent of protein synthesized that is retained for growth). During a ~4 month growth
period for larvae of O. meridionalis, the average protein depositional efficiency was 5.2%. This contrasts with higher rates of depositional efficiency reported
for similar developmental stages of temperate echinoderm species. The biological significance of maintaining high rates of
macromolecular synthesis for species with low rates of cell division and low protein depositional efficiencies is intriguing
in the context of understanding the mechanistic bases of extended life spans and dispersal potential in response to changing
Antarctic environments. 相似文献
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