Tags:
create new tag
, view all tags

Seminar WS 2013/14

Ursprung des Lebens (Origin of Life)

Welcome to the seminar "Origin of Life"!

When?: Di 12:15 - 14:00
Where?:AB4, SR 003
Who: Wolfgang Weigand, PeterDittrich



Sprache / Language

If necessary, the seminar will be held in English. Ausarbeitungen können in jedem Fall auf Deutsch verfasst werden.

Content

In this seminar we will study the origin of life from various perspectives depending on the background of the participating students. In particular we will focus on how the formal sciences and computational approaches can help in understanding the emergence of the first (proto-)life forms.

In the first part (Week 1 - Week 3) we will whatch and discuss video lectures by Maynard Smith, Altman, Deamer, Szostak and others.

Sidney Altman and John Maynard Smith

  • Lecture by Sidney Altman Sterling Professor of Molecular Cellular and Developmental Biology at Yale University and Nobel Laureate in Chemistry (1989), delivers the Tetelman Fellowship Lecture on the origin of life.
  • Lecture by John Maynard Smith Royal Institution Discourse (1995). In modern organisms, there is a division of labour between two kinds of molecule: DNA, which stores and transmits genetic information, and proteins, which do all the work. They are connected by the 'genetic code', whereby DNA specifies what kinds of proteins can be made. This process of translation is well understood, but it is far too complicated to have arisen by chance in the primitive oceans. How can this apparent paradox be resolved?

David Deamer

Günter Wächstershäuser

Title: Chemical predetermination from the origin of life to the origin of Archaea and Bacteria

Conventional wisdom on the origin and early evolution of life attributes the emergence of all essential features of life to rare, random, accidental events within a large and chaotic field of chemical and genetic possibilities. The theory of a chemo-autotrophic origin of life by transition metal-catalyzed, autocatalytic carbon fixation in a volcanic flow setting gives a different picture. The paucity of possibilities of a synthesis of low-molecular weight organic compounds by carbon fixation cycles provides us with the perspective of a chemically predetermined sequence of events. It begins with an origin of autocatalytic carbon fixation cycles on transition metal minerals giving rise to lipids. It proceeds through the chemically predetermined lipophilization of mineral surfaces to an inevitable formation of mineral-supported, semi-cellular structures.

The membranes of these semi-cellular structures became self-supporting by the chemically predetermined emergence of wedge-shaped phosphoglycerol lipids. At that stage the emergence of the genetic machinery set in to supplement the primary, direct, chemically deterministic track of evolution by a secondary, indirect stochastic track of evolution by genetic chance events. This marks the beginning of Darwinian selection with an indirect adaptation of the emerging polymer sequences to the chemically predetermined possibilities of pathway evolution. It is proposed that the primary, track of direct evolution continued at least until the stage of the emergence of the domains Bacteria and Archaea.

More specifically, it is proposed that the organisms, which are ancestral to the Bacteria and Archaea had a membrane of a racemate of chiral phospho-glycerol lipids. Note that racemic membranes are known to segregate into a patchwork of homochiral membrane domains. In the absence of cell walls the population of ancestral organisms must have undergone frequent fusions and fissions leading to a partitioning into two subpopulations with a predominance of one lipid enantiomer or the other.

These two subpopulations served then as the placeholders for the later emergence of the domains of the Archaea and Bacteria. This simply required the emergence of enantioselective enzymes of lipid biosynthesis by genetic adaptation.

Jack W. Szostak

  1. Lecture by Jack W. Szostak (54:41) (Harvard/HHMI) Part 1: The Origin of Cellular Life on Earth

von Hazen

  1. Vortrag von Hazen

Papers Presented

Schedule


15.10.2013   First meeting, Introduction
22.10.2013   Background: S. Altman & J. Maynard Smith 
29.10.2013   Background: D. Deamer
05.11.2013   Background: D. Deamer and G. Wächtershäuser
12.11.2013   Background: J. Szostak Part I+II
19.11.2013   Background: J. Szostak Part III 
26.11.2013   preparation meeting for student's contribution
03.12.2013   preparation meeting for student's contribution
10.12.2013   Theresia Conrad, A Toy Model of Prebiotic Peptide Evolution
17.12.2013   Student's preparation
07.01.2013   Student's preparation
14.01.2014   Lukas Klimmasch, Origin of Evolution vs. Origin of Life  
21.01.2014   Suraj Krishnamurthy, The Last Common Ancestor
28.01.2014   Sebastian Krautwurst, Origin of Life as a Spatially Localized Stochastic Transition
04.02.2014   Closing Discussion

Possible topics:

  • Autocatalytic reations
  • Origin of home-chirality (cf. also Waechtershaeuser)
  • or, search your own topic ...

Books

-- PeterDittrich - 15 Oct 2013

Topic revision: r8 - 2014-10-09 - StephanRichter
 
This site is powered by the TWiki collaboration platform Powered by PerlCopyright © 2008-2019 by the contributing authors. All material on this collaboration platform is the property of the contributing authors.
Ideas, requests, problems regarding TWiki? Send feedback

antalya escort bursa escort eskisehir escort istanbul escort izmir escort