Lifelike biochemistry continued to unfold in sterilized soil

85 points by speckx 2 hours ago on hackernews | 9 comments

j16sdiz | an hour ago

It feels next would be trying isolate the component that make CO2. Try to use smaller sample. Put them under microscope, etc.
Obligatory Asimov: 'The most exciting phrase to hear in science, the one that heralds the most discoveries, is not "Eureka!" but 'That's funny...”'

buildsjets | 52 minutes ago

Reminds me of the Gamma Forest at Brookhaven National Labs. From 1961 thru 1978 they irradiated a section of the pine barrens forest with a cesium-137 source just to see what would happen. It sterilized the soil and hardly anything grows there, almost 50 years later.

https://maps.app.goo.gl/pJYr6qiZnMdVwLJS6

https://www.atlasobscura.com/places/brookhaven-gamma-forest

https://www.youtube.com/watch?v=GsuiLxcDuHY&t=925s

ErroneousBosh | 47 minutes ago

I'm guessing the distinct lack of Google Streetview on that circular bit of road nearby and the tracks implies a certain amount of resistance to access if you get off that dual carriageway to the west?

buildsjets | 23 minutes ago

That "circular bit of road" is the Relativistic Heavy Ion Collider, the second highest-powered particle accelerator on the planet.

https://en.wikipedia.org/wiki/Relativistic_Heavy_Ion_Collide...

This is huge news if true for evaluating soil experiments on Mars. They could give false positives for life if they only look for metabolic products.

cogman10 | 28 minutes ago

Not as much as you might think.

We've found amino acids almost everywhere we look, including astroids [1].

It seems that the building blocks of life pretty naturally and readily form. Which is a pretty strong indicator that life is likely fairly common outside earth.

[1] https://www.nasa.gov/news-release/nasas-asteroid-bennu-sampl...

adrian_b | 10 minutes ago

In the second part of the article there is an explanation which for me is the most plausible, and which would not be applicable to Martian soil.

Even if they killed all living beings in the soil, after their death the enzymes that are the catalysts for metabolism would just become dispersed in the soil and they continue to catalyze reactions like those of the Krebs cycle.

After many years of storage the molecules of the enzymes will be degraded, i.e. they will break into fragments. That again does not mean much, because the catalytic action of the enzymes is typically caused by very small parts of the enzymes, which can remain intact even after fragmentation.

In general, the biggest part of an enzyme is just a scaffold that attaches the enzyme in precise places of a cell, usually on some intracellular membranes, so that a great number of enzymes can be assembled like a production line in a factory, to coordinate the metabolic reactions for maximum efficiency.

After death and enzyme fragmentation, even after many years the catalytic fragments of the enzymes can still catalyze reactions like those of the Krebs cycle.

It is also possible that some of the observed chemical reactions are catalyzed by minerals present in the soil and not by remnants of the enzymes from the dead cells, but for now no evidence has been gathered about this.

Moreover, there are enzyme residues which are difficult to distinguish from abiotic minerals. Some of the enzymes involved here contain a catalytic part formed by a cluster of iron and sulfur atoms, which are attached to a protein molecule. That iron-sulfur cluster is pretty much identical with a very small fragment of an iron sulfide mineral.

greenbit | 9 minutes ago

This is great, if you have significant amounts of free oxygen to work with, which early earth evidently did not. Would be interesting to see if anaerobic metabolism could also occur without cellular confinement.