Constitutive Expression Differences and Thermal Responses of Stress-Associated Transcripts in Pacific Abalone

We examined basal and exposure-associated transcript abundance in Pacific abalone. Pi3k, Akt, mTOR, Hsf1, Hsp70, and Hsp90 were compared across five anatomical samples and between heat-selected and common populations after identical two-week acclimation. Five transcripts were examined during adult exposure to 30 °C for up to 72 h and after a 15 min larval heat shock. Basal groups had three animal samples; population and adult groups had two or three analyzed samples. Larval groups comprised three pools of 500 individuals. Qualitative histology used three animals per condition. Welch tests on log2 values used Holm correction. Selected animals had higher hepatopancreatic Pi3k, Akt, mTOR, and Hsp70 levels. Hepatopancreatic Hsf1/Hsp70 means were highest at 12 h and Pi3k/Akt means at 24 h; peak times were not statistically compared. All five transcripts increased within late-veliger samples, without establishing a stage-by-treatment interaction. Histology showed local discontinuities, including in controls. These patterns identify candidate transcript-level indicators. One adult tank per condition, absent time-matched control comparisons, unverified larval culture independence, small samples, normalization uncertainty, population-history confounding, and absent protein endpoints and direct tolerance measurements limit interpretation.