MSc Exit Seminar – Mouska Patang (Buck Lab)

H₂S as a potential O₂ sensor in C. picta cerebrocortex  

Abstract: 

The freshwater Western painted turtle, Chrysemys picta, is one of the most anoxia-tolerant vertebrates able to withstand months of anoxic conditions under ice-covered lakes. The turtle demonstrates remarkable recovery upon reoxygenation without sustaining organ damage associated with oxidative stress. It owes its winter survival to metabolic suppression, enhanced glycogen stores and proton buffering. Our recent work of pyramidal mitochondrial membrane potential depolarization and mitochondrial Ca²⁺ release has rendered the mitochondria a possible oxygen sensor in turtle neurons. However, the initial signaling molecule remains unknown. We speculate hydrogen sulfide (H₂S) to act as a molecular oxygen sensor in neurons by its action on Ca²⁺ channels during anoxic stress. I have demonstrated an anoxia-dependent H₂S increase (~40%), and a H₂S-induced Ca²⁺ increase (~3%) directly via exogenous Na₂S and indirectly via inhibition of the H₂S synthesizing enzymes. Thus, we postulate H₂S to have retained its primordial significance by switching from its role as a final electron acceptor 4Bya, to an oxygen sensor 2.5Bya.

Join Zoom Meeting:

Friday, November 13^th, 2020 at 11:00am

https://us02web.zoom.us/j/83089711556?pwd=S3VlMDY5allwaUs3NVNETktaQWFDQT09

Meeting ID: 830 8971 1556

Host: Leslie Buck (les.buck@utoronto.ca)