The effect of temperature on the circadian rhythmicity of the neuroendocrine axis of the blue crab Callinectes sapidus (CRUSTACEA BRACHYURA).

• Grant number: 24/03064-4
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date until: December 01, 2024
• End date until: September 30, 2027
• Field of knowledge: Biological Sciences - Physiology - Compared Physiology
• Principal Investigator: Ana Maria de Lauro Castrucci
• Grantee: Giovanna Zanetti
• Host Institution: Instituto de Biociências (IB). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

The marine ecosystem is subjected to a wide variety of environmental cycles, such as photoperiod and temperature. These cycles provide cues to marine species, leading to the adjustment of biological clocks that control their physiology, ranging from circadian to circalunar and seasonal rhythms. The eyestalk in crustaceans is considered the center of endocrine control, containing a range of photoreceptors, neuropeptides, and modulators involved in circadian regulation, attributed to the X-organ neurosecretory system, which is responsible for the synthesis, storage, and release of hormones that control the reproductive neuroendocrine axis. Temperature variations determine the thermal tolerance limits in species, allowing the quantification of the effects of climate change on marine organisms. Anthropogenic actions are causing a negative impact on current and future climatic conditions, leading to significant physiological changes in organisms. Therefore, we ask whether high and low temperatures impact the reproductive neuroendocrine axis and rhythmicity of the blue crab Callinectes sapidus (Rathbun, 1896). To address this question, this project proposes: 1) To annotate the transcriptome of C. sapidus; 2) To establish proteogenomics in different tissues; 3) Under control conditions and at high and low temperatures in juvenile and adult females over 24 hours: 3.1) To investigate changes in the X-organ/sinus gland, Y-organ, hepatopancreas, and ovary through comparative proteomics; 3.2) To analyze the expression of clock genes, opsins, TRP channels, and tissue-specific genes in the reproductive neuroendocrine axis through quantitative PCR; 3.3) To measure circulating levels of reproductive neuroendocrine axis hormones using ELISA; 3.4) To examine morphological changes in the ovaries of females through histology and to assess gonadosomatic and hepatosomatic indices.