Chalk Talks

2017 Sep 21

Sukrit Ranjan (MIT SCOL / Sasselov Group Alumni) and Zoe Todd (Sasselov Group ) -“Controversies in the Origin of Life: Metabolism-first vs. Replication-first”

9:00am to 10:00am

Location: 

Naito Laboratory, Room 205, 12 Oxford Street

Abstract:

There have long been two major stances on the origin of life: one rooted in the belief that metabolic cycles originated abiotically, producing energy used to power the earliest life (metabolism-first); while the other stipulates that genetic material containing information developed first (replication-first). While both metabolism and informational transfer are important for life today, it remains unclear which theory, if either, is correct. We will present the current evidence in favor and opposing both theories and discuss how these ideas fit into past and...

Read more about Sukrit Ranjan (MIT SCOL / Sasselov Group Alumni) and Zoe Todd (Sasselov Group ) -“Controversies in the Origin of Life: Metabolism-first vs. Replication-first”
2017 Nov 09

Constantin Giurgiu (Szostak Lab) - "The Surprising Roles of Azoles in Prebiotic Chemistry: A Play in Three Acts"

9:00am to 10:00am

Location: 

Naito Laboratory, Room 205, 12 Oxford Street

Abstract:

 

When you hear prebiotic chemistry you immediately think large and complex molecules, present in all life forms on Earth, like proteins or nucleic acids. However, on the early earth the abundant molecules were more likely small and simple like cyanamide and glycoaldehyde. Elucidating a pathway from small and simple to large and complex is the main question of prebiotic chemistry. Current day synthetic chemistry has found an answer: separation methods, controlled reaction conditions and hordes of...

Read more about Constantin Giurgiu (Szostak Lab) - "The Surprising Roles of Azoles in Prebiotic Chemistry: A Play in Three Acts"
2017 Dec 07

Dr. Laura Kreidberg - "Exoplanet Atmosphere Characterization, Present and Future"

9:00am to 10:00am

Location: 

Naito Laboratory, Room 205, 12 Oxford Street

Abstract

We now know that exoplanets abound in the Galaxy, with most stars hosting at least one planet. These recently discovered worlds are much more diverse than the planets in the Solar System, and raise many questions about their formation, evolution, and habitability. To address these questions, we turn to atmosphere characterization, which provides a wealth of additional information about the planets. I will discuss the state of the art in atmosphere studies, focusing on recent high-precision, space-based observations of hot Jupiters and warm Neptunes. These studies...

Read more about Dr. Laura Kreidberg - "Exoplanet Atmosphere Characterization, Present and Future"
2017 Oct 05

Hanon McShea (Kacar Lab) - "Reconstructing Ancestral Nitrogenases Reveals Ancient Redox-Linked Selective Pressure"

9:00am to 10:00am

Location: 

Naito Laboratory, Room 205, 12 Oxford Street
Nitrogenase is the only protein on the planet capable of fixing nitrogen, yet it is extremely sensitive to oxygen and has a very high metal requirement (38 Fe + 1 Mo/V/Fe). It is thought to have originated in the Archean or early Proterozoic, and thus its evolutionary history likely includes adjustment to at least one major change to the redox state of the Earth system. We used ancestral sequence reconstruction to understand the evolution of biological nitrogen fixation through Earth history. We reconstructed ancestral nitrogenase sequences by creating... Read more about Hanon McShea (Kacar Lab) - "Reconstructing Ancestral Nitrogenases Reveals Ancient Redox-Linked Selective Pressure"
2017 May 04

Bishnu Bastakoti (Perez-Mercader Group) "Chemical Synthesis and Spontaneous Formation of Giant Polymer Vesicles"

9:00am to 10:00am

Location: 

Naito Laboratory (Room 205), 12 Oxford Street

Abstract:

 

Polymer vesicles (polymersomes) are a synthetic analogue of liposomes. Block copolymers that mimic the lipid amphiphilicity can self-assemble into nano/micro sized polymer vesicles. Physicochemical properties of polymer vesicles such as stability, fluidity, permeability can be easily tuned due to the rich chemistry of block copolymers. In this talk, I will discuss the facile one pot synthesis of polymeric vesicles made of amphiphilic diblock copolymers through light mediated polymerization induced self-assembly and their potential applications. The growth of...

Read more about Bishnu Bastakoti (Perez-Mercader Group) "Chemical Synthesis and Spontaneous Formation of Giant Polymer Vesicles"
2017 Feb 02

Sukrit Ranjan (Sasselov Group) "The UV Surface Environment on Young Planets: Implications for Prebiotic Chemistry & Life on Other Worlds"

9:00am to 10:00am

Location: 

Naito Laboratory, Room 205, 12 Oxford Street

 

Abstract:  

Understanding the origin of life (abiogenesis) on Earth is key to understanding how it might start elsewhere. Recent laboratory studies suggest UV light may have played a critical role in the synthesis of molecules relevant to abiogenesis (prebiotic chemistry), such as RNA. I show that UV light interacts with prebiotic chemistry in ways that may be sensitive to the spectral shape and overall amplitude of irradiation. I use radiative transfer models to constrain the UV environment on early Earth (3.9 Ga). I find that the surface UV is...

Read more about Sukrit Ranjan (Sasselov Group) "The UV Surface Environment on Young Planets: Implications for Prebiotic Chemistry & Life on Other Worlds"
2017 Apr 06

"Understanding isotopic records of global carbon cycling" Elise Wilkes (Pearson Group)

9:00am to 10:00am

Location: 

Natio Laboratory, Room 205, 12 Oxford Street

Abstract: The carbon isotopic composition of algal organic matter preserved in marine sediments provides a window into the evolution of the global carbon cycle through geologic time, including variations in atmospheric CO2 levels. Traditional models for interpreting marine isotope records assume that these archives largely reflect kinetic isotopic discrimination by the carbon-fixing enzyme RubisCO.   However, recent measurements in our laboratory and in the literature appear to contradict this assumption, indicating that significant questions remain regarding the...

Read more about "Understanding isotopic records of global carbon cycling" Elise Wilkes (Pearson Group)

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