Acidification stress effect on umbonate veliger larval development in Panopea globosa.

Ocean acidification generates a decrease in calcium carbonate availability essential for biomineralization in organisms such as mollusks. This effect was evaluated on Panopea globosa exposing for 7 days umbonate veliger larvae to two pH treatments: experimental (pH 7.5) and control (pH 8.0). Exposure to pH 7.5 affected growth, reducing larval shell length from 5.15-13.34% compared to the control group. This size reduction was confirmed with electron microscopy, also showing shell damage. The physiological response showed an increase in oxygen consumption in larvae exposed to low pH with a maximum difference of 1.57 nmol O2 h-1 larvae-1 at day 7. The gene expression analyses reported high expression values for nicotinamide adenine dinucleotide (NADH) dehydrogenase and Perlucin in larvae at pH 7.5, suggesting a higher energetic cost in this larval group to maintain homeostasis. In conclusion, this study showed that acidification affected development of P. globosa umbonate veliger larvae.

Thermal Physiological Performance and Thermal Metabolic Scope of the Whelk Kelletia kelletii (Forbes, 1850) (Gastropoda: Neptuneidae) Acclimated to Different Temperatures.

nvestigations of thermal limits are crucial to understanding climate change ecology because it illuminates how climate will shape future species distributions. This work determined the preferred temperature, critical threshold limits represented by the Critical Thermal Maximum (CTMax) and (CTMin), thermal window, oxygen consumption rate and thermal metabolic scope of Kelletia kelletii acclimated to 13, 16.0, 19.0 and 22.0 ± 1°C to determine if this species is sensitive to global warming. The preferred temperature (PT) of Kellet's whelk was determined using the acute method. The acclimation temperature significantly affected the thermal preference of the marine snail (P < 0.05) and increased from 13.2 to 24.2°C as the acclimation temperature increased from 13.0 to 22.0°C. The PT was 13.4°C. The acclimation temperature did not significantly affect the CTMax (P > 0.05), obtaining a range of 29.2 to 30.2°C. The CTMin had an interval of 9.2°C, at acclimation temperatures of 13 to 16°C, and increased significantly (P < 0.05) at 12.3°C in the acclimation interval of 19-22°C. The thermal window for the different acclimation temperatures was 163.5°C2. The oxygen consumption rate of the snails increased significantly (P < 0.05) when the acclimation temperature increased from 13.0 to 22.0°C, peaking at 63.6 mg of O2 kg-1 h-1 w.w. in snails maintained at the highest acclimation temperature. The thermal metabolic scope increased significantly (P < 0.05) when the acclimation temperature was 13.0°C, with values of 68.7 mg O2 h-1 kg-1 w.w., then decreased significantly (P < 0.05) to 27.9 mg O2 h-1 kg-1 w.w at 32°C. Therefore, the thermal aerobic scope was highest at the temperatures that K. kelletii preferred. These results may partially explain their pattern of distribution on the Baja California coast.

Octopus maya white body show sex-specific transcriptomic profiles during the reproductive phase, with high differentiation in signaling pathways.

White bodies (WB), multilobulated soft tissue that wraps the optic tracts and optic lobes, have been considered the hematopoietic organ of the cephalopods. Its glandular appearance and its lobular morphology suggest that different parts of the WB may perform different functions, but a detailed functional analysis of the octopus WB is lacking. The aim of this study is to describe the transcriptomic profile of WB to better understand its functions, with emphasis on the difference between sexes during reproductive events. Then, validation via qPCR was performed using different tissues to find out tissue-specific transcripts. High differentiation in signaling pathways was observed in the comparison of female and male transcriptomic profiles. For instance, the expression of genes involved in the androgen receptor-signaling pathway were detected only in males, whereas estrogen receptor showed higher expression in females. Highly expressed genes in males enriched oxidation-reduction and apoptotic processes, which are related to the immune response. On the other hand, expression of genes involved in replicative senescence and the response to cortisol were only detected in females. Moreover, the transcripts with higher expression in females enriched a wide variety of signaling pathways mediated by molecules like neuropeptides, integrins, MAPKs and receptors like TNF and Toll-like. In addition, these putative neuropeptide transcripts, showed higher expression in females' WB and were not detected in other analyzed tissues. These results suggest that the differentiation in signaling pathways in white bodies of O. maya influences the physiological dimorphism between females and males during the reproductive phase.