Analía Pérez, Cintia Fraysse, Malena Pfoh, Claudia Boy

Development patterns and oxidative metabolismof antarctic sea stars

Introduction

Development patterns and oxidative metabolismof antarctic sea stars. Explore oxidative metabolism during gonadal maturation in Antarctic sea stars. Discover how brooding patterns reduce reactive oxygen species (ROS) and maternal antioxidants boost offspring fitness.

Abstract

Sea stars exhibit different development patterns that comprise indirect and direct development, including pelagic or benthic larvae, and planktotrophic or lecithotrophic nutrition. The purpose of our research was to study the general parameters of oxidative metabolism during female gonadal maturation in Antarctic sea stars with different development patterns. Summer sampling was performed in 2012 in Antarctica. Every asteroid was taxonomically identified, and its development pattern was established. Sex and the reproductive stage were determined through histological analyses. The general parameters of the oxidative metabolism were determined in mature ovaries by measuring reactive oxygen species (ROS) and total antioxidant capacity (TAC). The development patterns with internal or oral brooding presented a lower production of ROS than those with a broadcaster strategy. The free-living planktotrophic larvae pattern presented lower TAC values than both types of brooding patterns. The development patterns of free-living lecithotrophic larvae and facultative lecithotrophic larvae presented intermediate values of TAC but did not show significant differences. We concluded that species that offspring rapidly acquire the ability to feed during development (planktotrophic larvae) exhibit lower TAC and higher levels of ROS than the species that do not feed during their development, which will receive greater maternal supply of antioxidants, resulting in reduced ROS levels. The development patterns with brooding ensure better quality oocytes and higher fitness in offspring than those unprotected.

Review

This manuscript presents a fascinating investigation into the interplay between diverse reproductive strategies and oxidative metabolism in Antarctic sea stars. The study addresses a clear and important research question, aiming to elucidate how different development patterns—ranging from indirect to direct, and incorporating varied larval nutrition (planktotrophic vs. lecithotrophic) and parental care (brooding vs. broadcasting)—influence key oxidative stress parameters within mature female gonads. The methodological approach, involving meticulous taxonomic identification, histological assessment of reproductive stages, and established biochemical assays for Reactive Oxygen Species (ROS) and Total Antioxidant Capacity (TAC), appears robust and appropriate for a comparative analysis in this ecologically challenging environment. The findings offer compelling insights, revealing distinct patterns of oxidative metabolism linked to specific reproductive strategies. Notably, brooding development patterns (internal or oral) were associated with significantly lower ROS production compared to broadcaster strategies, suggesting a potential benefit of parental care in mitigating oxidative stress. Furthermore, the free-living planktotrophic larval pattern exhibited lower TAC values than brooding types, hinting at different antioxidant investment strategies. The authors' conclusion, proposing that species with maternal provisioning of antioxidants (non-feeding lecithotrophic larvae) benefit from reduced ROS levels compared to planktotrophic species that rapidly acquire the ability to feed, is a crucial interpretation. While the correlations are clear, the abstract could benefit from a slightly more explicit acknowledgment of the inferential nature of the "maternal supply of antioxidants" and the direct link to "better quality oocytes and higher fitness," even if these are ecologically sound hypotheses. Overall, this study makes a substantial contribution to our understanding of reproductive ecology and physiological adaptations in marine invertebrates, particularly within the context of extreme polar environments. It provides novel data demonstrating how evolutionary divergence in developmental strategies can manifest in quantifiable differences in cellular stress responses, with potential implications for offspring viability and fitness. The research is well-conceived and executed, offering valuable comparative data. With minor clarifications regarding the interpretive leap from observed oxidative markers to direct maternal supply and fitness outcomes, this work will undoubtedly be a significant addition to the literature. I recommend its publication following minor revisions.

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