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Re: Dinosaur osteocytes' preservation supported by molecular analysis
- To: DML <firstname.lastname@example.org>
- Subject: Re: Dinosaur osteocytes' preservation supported by molecular analysis
- From: David Marjanovic <email@example.com>
- Date: Thu, 18 Oct 2012 05:05:44 +0200
- In-reply-to: <CAMR9O1LiRD-_spnjNh6P1urqC6XRcdvJq=esNB2vPF0CG9wkKQ@mail.gmail.com>
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- Sender: owner-DINOSAUR@usc.edu
Heh. Schweitzer presented it today. :-) Was pretty impressive.
The discovery of soft, transparent microstructures in dinosaur bone
> consistent in morphology with osteocytes was controversial.
The first half of the talk went into showing that they're indeed
osteocytes and not a biofilm. Their filopodia are half as thin as most
We present immunological and mass spectrometry evidence for
> preservation of proteins comprising extant osteocytes (Actin,
> Tubulin, PHEX, Histone H4) in osteocytes recovered from two non-avian
Huh. Mass spectrometry wasn't mentioned today.
Actin and tubulin occur pretty much everywhere in eukaryotes. So does
histone H4, but the point is that histones are specific to eukaryotes.
PHEX is an enzyme that occurs only in osteocytes (not even their
precursors, osteoblasts); the antibody they used to stain it is specific
to avian PHEX and does not stain alligator osteocytes. It stains
*Tyrannosaurus* and *Brachylophosaurus* osteocytes (the latter a little
Furthermore, antibodies to DNA show localized binding to these
> microstructures, which also react positively with DNA intercalating
> stains propidium iodide (PI) and 4′,6′-diamidino-2-phenylindole
> dihydrochloride (DAPI).
As I got to point out in the questions session, all these things
probably bind to tiny fragments of DNA or even isolated nucleobases.
Schweitzer agreed that DNA that can't be sequenced is basically useless
and that that may well be what she found there.
We propose mechanisms for preservation of cells and component
> molecules, and discuss implications for dinosaurian cellular
No time for that in the talk.