Protein Metabolism in Lecithotrophic Larvae (Gastropoda: Haliotis rufescens)

Area of Science:

• Marine biology
• Developmental biology
• Biochemistry

Background:

• Lecithotrophic development in marine invertebrates relies on endogenous nutrient stores.
• Understanding macromolecular metabolism is key to explaining developmental strategies in nonfeeding larvae.
• Abalone (Haliotis rufescens) larvae provide a model for studying nutrient utilization during early life stages.

Purpose of the Study:

• To quantify protein depletion, synthesis, and turnover rates in Haliotis rufescens larvae.
• To elucidate the role of protein metabolism in lecithotrophic development and maintenance.
• To identify major protein classes and turnover dynamics in abalone larvae.

Main Methods:

• Measurement of protein content, fractional synthesis rates, and turnover rates in Haliotis rufescens larvae.
• Analysis of protein profiles using one-dimensional and two-dimensional gel electrophoresis.
• Radiolabeling of larval proteins with 35S-methionine and cysteine.

Main Results:

• Protein content decreased linearly by 34% during 8-day larval development.
• Fractional protein synthesis rates declined from 40% in trochophores to 14% in veligers.
• Protein turnover involved hundreds of proteins, with energy from protein loss supporting 20-79% of turnover costs.

Conclusions:

• Haliotis rufescens larvae exhibit high protein turnover rates (up to 40% daily) to support maintenance metabolism.
• Dynamic protein metabolism is essential for the development of nonfeeding lecithotrophic larvae.
• Specific high-molecular-weight proteins (88 and 121 kDa) dominate larval protein pools.