Title:
Grounding Biology: "Abiotic" Protection of Microbial Cells Based on Geochemical Interactions and Their Influence on the Origins and Evolution of Life

Abstract:
Prokaryotic microorganisms were the first forms of cellular life on Earth. Their emergence depended on and was influenced by the surrounding physio- and geo-chemical environment. Survival of microbial cells depended then, and continues to depend now, on the ability to defend essential biomolecules against damages from physiochemical stresses. Modern prokaryotes rely on a vast array of complex enzymatic processes to protect against such damages, but recent studies have also revealed non-enzymatic, or "abiotic" mechanisms of damage mitigation. These mechanisms bridge the geochemical and biological worlds, as they are based on simple chemical reactions involving a range of metal ions and small molecules in mineral/microbial interactions, both extracellular and intracellular. Their simplicity and wide-spread use among diverse groups of prokaryotes suggest an early appearance in the evolution of life on Earth. In addition, the same abiotic mechanisms appear to provide resistance !
against multiple environmental stresses (pH, temperature, radiation, high pressure), extending well beyond the native habitat of a given microorganism. Abiotic mechanisms of damage mitigation thus reinforce the essential and dynamic nature of mineral/microbial interactions in the origins and evolution of life.

This seminar will be an opportunity for an open discussion on the nature of mineral/microbial interactions in the evolution of microbial life (on Earth or elsewhere), particularly focused on how these extracellular and intracellular interactions serve to protect essential biomolecules from potentially damaging physiochemical conditions.

Dr Adrienne Kish is an Associate Professor of microbiology at the National Museum of Natural History (Muséum National d'Histoire Naturelle) in Paris, France specializing in extremophiles and astrobiology.