Genetic analysis of carbohydrate metabolism in Strongylocentrotus purpuratus larvae during laboratory experiments with different food treatments

Strongylocentrotus purpuratus (Stimpson 1857) originally collected in November 2022 from La Jolla, USA (Lat: 32.842674; Long: -117.257767) were held in flow-through tanks which were filled with water from Kiel Fjord adjusted to 31.5 psu in the Christian-Albrechts-Universität zu Kiel at 10 °C. For experimental characterization of carbohydrate digestion between September and November 2023 S. purpuratus larvae were generated by gently shaking adult males and females and held in climate chambers at 15°C and 31.5 psu up to 10 days under two different food conditions. For genetic analysis of carbohydrate metabolism RT-qPCR was conducted. In brief, mRNA of samples from nine different time points (2 days post fertilization (dpf) – 10 dpf, n=4) was isolated and reverse transcripted into cDNA. Primer pairs were designed through NCBI primer blast, specifically targeting exon junctions of the selected carbohydrates enzyme genes for which the mRNA sequence is accessible in the S. purpuratus genome database echinobase.org. Genes were selected based on transcription patterns of the genes during early development. Primer specificity was validated through standard PCR, confirming the amplification of a single, specific product within the anticipated size range. Gene expression utilized the ∆∆CT method, and levels were normalized to the stable housekeeping gene EF1a (SPU_000595).