Seasonal variation of thermogenic mechanisms in the Tegu lizard Salvator merianae

• Grant number: 22/13835-2
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• Effective date (Start): January 01, 2023
• Effective date (End): December 31, 2026
• Field of knowledge: Biological Sciences - Physiology - Compared Physiology
• Principal Investigator: Kênia Cardoso Bícego
• Grantee: Livia Saccani Hervas
• Host Institution: Faculdade de Ciências Agrárias e Veterinárias (FCAV). Universidade Estadual Paulista (UNESP). Campus de Jaboticabal. Jaboticabal , SP, Brazil
• Associated research grant: 21/10910-0 - Physiological capacities and resilience facing climate change: exploring the functional dimension in ectothermic vertebrates, AP.TEM

Abstract

The experimental work plan will focus on carrying out experiments and analyzes regarding muscle metabolism related to physiological and behavioral investment in reproduction concentrated in a specific phase of the year, when there is more favorable climate and greater availability of food. The tested hypothesis is that the seasonal variation of the expression of proteins involved in the energy metabolism of the skeletal muscle of tegu lizards will follow the profile: greater expressions during the spring, related to the reproductive investment; followed by intermediate expressions during the non-breeding activity phase in summer, and the smallest expressions occurring during winter hibernation. For this, the seasonal variation of the proteome involved in muscle energetics will be investigated, which includes proteins of the respiratory chain (OXFOS and uncoupling), the glycolytic pathway and the citric acid cycle, as well as proteins linked to the calcium cycle of the sarcoplasmic reticulum and ATPases of cell membrane. In addition to the protein expression itself, the functional dimension of muscle energy production will also be investigated, as related to the activities of Ca++ ATPase (SERCA) and of the proton uncoupler protein ANT, by measuring heat production, using direct calorimetry (in minicalorimeter), of fresh skeletal muscle samples. In this case, the hypothesis is that the highest energy production and uncoupling related to the activities of these proteins will also be measured during the spring reproduction phase. It is expected that all of the expressions and activities related to muscle energy will be related to the higher levels of annual metabolic and motor activities and to the peaks of hormones related to the modulation of energy metabolism, such as thyroid and corticosterone, and reproduction, such as estrogen and testosterone. (AU)