#  Professor Alex Sessions (Caltech) - "The hydrogen isotope fingerprints of life." 

 



####  calendar\_today Date and Time 

 **October 17, 2018** 

 04:00PM - 05:30PM EDT 

####  pin\_drop Location 

 **Haller Hall, Geological Museum, 24 Oxford Street**  



 

 



 

 Abstract:

 Most biologic processes exhibit significant deuterium isotope effects, which can measurably alter the abundances of stable hydrogen isotopes (1H and 2H) in biomolecules. A longstanding hope is that different organisms, reactions, or environments will result in characteristic 2H/1H ratios that we can learn to interpret. In this seminar I will summarize our efforts to understand the biochemical mechanisms that control H-isotopic fractionation in lipids, molecules that are well preserved in the sedimentary record and potentially offer insight into ancient metabolism and environments. In contrast to C and N isotopes, H-isotope signals arise from a combination of effects distributed across central metabolism, particularly those that conserve reducing power as NADPH. Both depletions and enrichments of 2H in the same environment are simultaneously possible, and provide a potential biosignature. We will conclude by considering the likelihood of such fingerprints being preserved in rocks from the early Earth, or in extraterrestrial materials.



 

 



 

 

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