Comments on: Extremophilia

By: D.radio

D.radio — Thu, 11 May 2006 09:59:01 +0000

Anybody knows what time need Deinococcus for have their mitosis? and what type of grow table it have?
I’m a student of Biotechnology and I needed for a work.

By: Deinococcus

Deinococcus — Tue, 21 Feb 2006 05:12:30 +0000

The debate about ALH84001 continues, but scientific consensus after a decade does not support the original paper published by McKay. That said, the decision by Science to publish the report was good since it forced the community to think carefully about the topic of biosignatures and what to look for in the future. Unfortunately, a Mars sample return mission seems very far away.

By: Plato

Plato — Fri, 17 Feb 2006 05:38:03 +0000

Probability 1, by Amir D. Aczel, page 99,

In 1994 Allan Hills 84001 was handed over to David Mckay of Nasa’s Johnson Space Center. Mckay asembled a nine-memebr team including scientists at NASA, Stanford University, the Universty of Georgia, and McGill University in Montreal. The team endeavored to determine whether there were any signs of life on the meteorite

Well?

By: Deinococcus

Deinococcus — Fri, 17 Feb 2006 00:31:30 +0000

For the latest on Deinococcus, see http://www.usuhs.mil/pat/deinococcus/index_20.htm.

Stay tuned for astrobiology-relevant work on radiation-driven microbial ecosystems and how manganese protects proteins, not DNA, during irradiation. Curious about what all of you are being taught on why ionizing radiation kills cells.

Mike

By: Dumb Biologist

Dumb Biologist — Fri, 27 Jan 2006 04:12:32 +0000

P. aeroginosa can even grow in distilled water, but if it was sterilized water, it isn't aseptic any longer if something is growing in it. Anway, the reason it can grow in distilled water is because even that has some traces of shmutz in it that microbes with very simple nutritional needs can thrive in (sort of). Actually, I think most examples of the genus Pseudomonas (maybe I should use "pseudomonads") do well in a huge range of conditions, and they're not picky eaters at all.

By: Paul Orwin

Paul Orwin — Fri, 27 Jan 2006 03:57:53 +0000

Something I didn’t expect to see at CV! Some loose use of the word “sterile” over here. I think you mean “sterilized”. Lots of things get sterilized, very few things are sterile (in the sense of abiotic). Bacteria are remarkably good at being where they ought not to be (by our standards). BTW, Deinococcus was recently found in the human stomach (a pretty extreme place as wellk, but apparently not as bad as we thought).

By: Dumb Biologist

Dumb Biologist — Fri, 27 Jan 2006 01:57:23 +0000

I don’t know that much about D. rad. molecular biology, but there’s repair, and then there’s repair+complete genomic redundancy at all times. When bacteria suffer a lot of DNA damage (as I’m sure D. rad. does in extreme environments), they typically resort to something called an “SOS response”. Repairing double-strand lesions requires replication of DNA, but when damage piles up too quickly for careful error-correction, the SOS response allows for quick-and-dirty replication that sacrifices accuracy for efficiency. If bacteria constantly have to SOS, the mutations will pile up to lethal proportions.

I’m guessling D. rad. can just say “Screw that, I got a handy, carefully synthesized extra copy right here. And a few more where that came from.”

That’s a pretty good trick, to be able to carry around multiple extra genomes for repair whenever you need it, and cope with it all the while. Look at what happens to us when we get even one extra chromosome.

By: Philip Downey

Philip Downey — Thu, 26 Jan 2006 20:32:30 +0000

I didn’t like that APOD very much, because they made the ability to repair DNA sound very exotic. Except for viruses, every organism can repair its DNA. Bacteria, us, and everything in between, can all do it.

Uncle Al: there’s also Pseudomonas aeruginosa, which grows pretty much anywhere, even sterile water containers.

By: Sean

Sean — Thu, 26 Jan 2006 20:21:11 +0000

I don’t think that even D. rad could survive if, say, the neutron were lighter than the proton, or the vacuum energy were at the Planck scale. But I do agree that many anthropic arguments rely to heavily on extrapolations about our local forms of life.

By: Elliot

Elliot — Thu, 26 Jan 2006 19:10:26 +0000

Doesn’t the existence of more extreme forms of life tend to “relax” any anthropic constraints on fundamental parameters making the anthropic principle less predictive. In particular if complex information processing was “discovered” in a non-dna based/non-hydrocarbon environment it would seem to me that the Anthropeople would have some “splaning to do”.

Elliot