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Below are the 20 most recent journal entries recorded in "How Life Began" -- Abiogenesis and Related Topics' LiveJournal:

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Thursday, November 2nd, 2006
6:37 am
LIFE - A Journey Through Time

X-posted in my own journal.
Friday, August 26th, 2005
11:48 pm
Early Oxygen, Hydrogen and Iron
Model Gives Clearer Idea Of How Oxygen Came To Dominate Earth's Atmosphere
A number of hypotheses have been used to explain how free oxygen first accumulated in Earth's atmosphere some 2.4 billion years ago, but a full understanding has proven elusive. Now a new model offers plausible scenarios for how oxygen came to dominate the atmosphere, and why it took at least 300 million years after bacterial photosynthesis started producing oxygen in large quantities.

The big reason for the long delay was that processes such as volcanic gas production acted as sinks to consume free oxygen before it reached levels high enough to take over the atmosphere, said Mark Claire, a University of Washington doctoral student in astronomy and astrobiology. Free oxygen would combine with gases in a volcanic plume to form new compounds, and that process proved to be a significant oxygen sink, he said.

Meteoric iron consumes oxygenCollapse )
Friday, December 17th, 2004
12:35 pm
Evidence of Life's Beginnings Written in Stone
By Dennis O'Brien
Sun Staff
Originally published December 17, 2004

Researchers studying rocks from Greenland announced today that they've uncovered evidence to show when life on earth began.

Analysis shows the rocks may have been host to our earliest ancestors: single-celled organisms that lived 3.85 billion years ago.

If the dating is accurate, the rocks push back the biological record of life on earth by about 450 million years.Not quite true, but ...Collapse )
Wednesday, October 27th, 2004
11:14 pm
Meteoric phosphate
Cf. SpaceFlight Now:
Schreibersite [iron-nickel phosphide] is a metallic compound that is extremely rare on Earth. But it is ubiquitous in meteorites, especially iron meteorites, which are peppered with schreibersite grains or slivered with pinkish-colored schreibersite veins.

Last April, Pasek, UA undergraduate Virginia Smith, and Lauretta mixed schriebersite with room-temperature, fresh, de-ionized water. They then analyzed the liquid mixture using NMR, nuclear magnetic resonance.

"We saw a whole slew of different phosphorus compounds being formed," Pasek said. "One of the most interesting ones we found was P2-O7 (two phorphorus atoms with seven oxygen atoms), one of the more biochemically useful forms of phosphate, similar to what's found in ATP."

Previous experiments have formed P2-07, but at high temperature or under other extreme conditions, not by simply dissolving a mineral in room-temperature water, Pasek said.
In contrast, apatite (the most common terrestial mineral phosphate) does not dissolve in such a complicated way. We also have a nice indirect tie-in with iron sulfide.
Friday, July 23rd, 2004
10:35 am
Selective amplification by auto- and cross-catalysis in a replicating peptide system.
Nature. 1998 Dec 3;396(6710):447-50.
Selective amplification by auto- and cross-catalysis in a replicating peptide system.

Yao S, Ghosh I, Zutshi R, Chmielewski J.
Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, USA.

Self-replication has been demonstrated in synthetic chemical systems based on oligonucleotides, peptides and complementary molecules without natural analogues. However, within a living cell virtually no molecule catalyses its own formation, and the search for chemical systems in which both auto- and cross-catalysis can occur has therefore attracted wide interest.

One such system, consisting of two self-replicating peptides that catalyse each other's production, has been reported. Here we describe a four-component peptide system that is capable of auto- and cross-catalysis and allows for the selective amplification of one or more of the products by changing the reaction conditions.

The ability of this system selectively to amplify one or more molecules in response to changes in environmental conditions such as pH or salt concentration supports the suggestions that self-replicating peptides may have played a role in the origin of life.
===|==============/ Level Head
Thursday, July 22nd, 2004
4:50 pm
From Nature 2002:
New theory for origin of life
Mineral cells might have incubated first living things.

4 December 2002

Iron sulphide honeycomb: a fertile environment.

Life on Earth may have begun in rocks on the ocean floor. More than 4 billion years ago, tiny cavities in minerals may have served as the first cells, two biologists are proposing1. Other researchers argue that the idea leaves many questions unanswered.

Iron Sulfide Life?Collapse )
Wednesday, July 21st, 2004
9:23 am
Tuesday, April 6th, 2004
10:32 am
Science on verge of new `Creation'
Science on verge of new `Creation' --------------------
Labs say they have nearly all the tools to make artificial life

By Ronald Kotulak
Tribune science reporter

March 28, 2004

More than 3.5 billion years after nature transformed non-living matter into living things, populating Earth with a cornucopia of animals and plants, scientists say they are finally ready to try their hand at creating life.Self-weaving sweaters?Collapse )
Wednesday, March 17th, 2004
9:03 am
Thermophiles and Extremophiles (cross posted from my journal)
These interesting critters may be illustrating how life got started on the planet. It's a pretty readable presentation with images.


===|==============/ Level Head
Monday, March 15th, 2004
4:55 pm
Yellowstone Could Help Find Life on Mars

Yellowstone Could Help Find Life on Mars

The Associated Press
Monday, March 15, 2004; 7:42 AM

YELLOWSTONE NATIONAL PARK, Wyo. - A study of microscopic organisms that inhabit the park's hot springs may help NASA researchers in their efforts to find life on Mars.

The organisms, called thermophiles, have lived in the boiling waters of springs in Yellowstone National Park for billions of years.Read more...Collapse )
Sunday, March 14th, 2004
5:41 pm
Coenzyme A Biosynthesis: Reconstruction of the Pathways
The last post got some commentary! So to keep you from getting too Hungary, we have something else on the table...
AbstractCollapse )
Saturday, March 13th, 2004
6:15 pm
Prospects of a computational Origin Of Life endeavor. (OOL@home)
This one's fairly readable -- and introduces the concept of OOL@home (in the fashion of SETI@home).
Orig Life Evol Biosph. 2004 Feb;34(1-2):181-94.Read more...Collapse )
5:24 pm
5:03 pm
What does a molecule want?
Biosystems. 2004 Jan;73(1):1-11.

What does a molecule want? The myth of the self-replicating molecule (comments on the "selfish-gene" paradigm).

AbstractCollapse )
2:02 pm
1:59 pm
Sunday, March 7th, 2004
12:53 pm
Handedness and Dark Matter
The asymmetry of existence: do we owe our existence to cold dark matter and the weak force?
A left-handed complementCollapse )
Thursday, March 4th, 2004
9:50 am
Slideshow discussion of possible prebiotic carbon fixation cycles
This is a Powerpoint-style PDF presentation on NASA's web site.

It's interesting, and pretty readable -- but it was intended to accompany a discussion, and is not a complete substitute for the discussion.

There's some information I had not seen before, such as a graph of the effect of impacts on the depths of oceans.

The slideshow takes you through the chemistry at a fairly, um, elementary level.

===|==============/ Level Head
Wednesday, March 3rd, 2004
12:09 pm
Tuesday, March 2nd, 2004
3:20 pm
Autotrophic CO2 fixation pathways in archaea (Crenarchaeota)
Hugler M, Huber H, Stetter KO, Fuchs G.
Mikrobiologie, Institut fur Biologie II, Universitat Freiburg,
Schanzlestrasse 1, Germany.

Representative autotrophic and thermophilic archaeal species of different families of Crenarchaeota were examined for key enzymes of the known autotrophic CO(2) fixation pathways.Abstract continuesCollapse )
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