How to Preserve an Ostrich Cell

We have a long article – with an even longer back story – today from Brian Thomas, called Dinosaur Soft Tissue Preserved by Blood?

For many years now Mary Higby Schweitzer has been investigating soft tissue and other biomolecular remains from inside dinosaur bones that are 70 million or so years old. For equally many years young Earth creationists like Brian Thomas have been pointing to these soft tissues and insisting that they could not last nearly so long, and so therefore the Earth is young. In this article Thomas says:

The scientific community has long shown its desperation to defend mainstream fossil ages against the short shelf-life of soft-tissue fossils.

This is, of course, a gross mischaracterisation of the debate. It is instead an internal controversy within the scientific community: some scientists insist that soft tissues could not survive millions of years, and point to other explanations for the observed results. On the other side Schweitzer – who is no friend to the creationists – is aiming to both prove that what she and her colleagues are seeing is real and provide a mechanism for its preservation. YECs like Brian Thomas stand outside this discussion, and pick and choose from the arguments presented those that they can make agree with their own position. They accept uncritically both that the soft tissues are real and the claim that they could not have survived millions of years, and while Schweitzer’s arguments against the explanations put forward by her opponents (bacterial biofilms being the most quoted) her own ideas about preservation have largely been ignored by the likes of Thomas until now.

A little over a year ago I wrote How to Preserve a Dinosaur Cell. In that post I examined part of a paper recently published by Schweitzer in which she went over a preservation mechanism originally hypothesised in 2007. It was argued that iron, released from hemoglobin and myoglobin after death, would precipitate a chain reaction that would lead to the crosslinking of both proteins and the fatty acids that cell membranes are made of. The upshot of this is that both could potentially be preserved much longer than otherwise might be expected, producing what had been observed previously.

In a new experiment, published in the Proceedings of the Royal Society B, Schweitzer and colleagues have tested this hypothesis by using ostrich blood vessels as a model for dinosaur tissue and subjecting them to a high concentration of blood lysate – what you get after the cells are destroyed, as would happen during decay – to ensure the supply of iron. They found that while untreated blood vessels decayed noticeably within 3 days, the treated vessels “have remained intact for more than 2 years at room temperature with virtually no change.” In other words it seems that the iron can increase the preservation time of the tissues by more than 200 times.

Previously, though without sound basis, Thomas has used the figure of a million years as his outside estimate of how long soft tissues like collagen could last. If iron can cause a two-hundredfold increase then none of the examples he used back in May are an issue and one of his favourite arguments is ruined forever. He begins his article therefore by saying:

Researchers are now suggesting that iron embedded in blood proteins preserved the still-soft tissues, cells, and molecules discovered inside dinosaurs and other fossils after the creatures were buried in sediments. The ability to justify millions of years is at stake, and this study promises to do just that. What are its merits and demerits?

Of course, this is not a new “suggestion,” but a six year old hypothesis now getting experimental support. But until now – with Schweitzer making the news not with a new soft tissue find that Thomas can exploit but with evidence that they can be preserved – he has not been forced to address it.

After explaining the experiment he says:

These results are unique and compelling. But do they really justify the study authors’ claim that this iron preservation phenomenon explains how dinosaur tissues lasted for tens of millions of years?

He has numerous points of criticism. The first that he mentions is:

For an experiment to really explain an effect lasting for millions of years, shouldn’t it gather enough time-related measurements to estimate the maximum time that iron-treated soft tissues could last? Only then could researchers directly compare that maximum time with fossils’ evolutionary ages. Schweitzer’s report did not show these kinds of results.

Many of Thomas’ objections relate to the fact that this paper, while reporting the results of a “compelling” experiment, does not prove absolutely everything he wants addressed. It’s my impression that if Schweitzer was required to only report back once she had run her experiment long enough to determine the maximum time that her blood vessels could have survived we would never have heard from her again. Instead, after showing a massive >24000% increase in preservation time she decided to publish what are already formidable results. It doesn’t seem that two years was even long enough for any decay to be measured at all, so Schweitzer may well come back in twenty years or so with the numbers Thomas wants.

Beyond this, Thomas offers four reasons why he thinks this study shows that iron could not “keep soft tissues intact for millions of years,” or at least doesn’t show that it could.

First, “Ostrich vessels were incubated in a concentrated solution of red blood cell lysate,” according to the study authors. Their procedure involved extracting and purifying iron from blood. But ancient dinosaur and other fossils did not have the advantage of scientists treating their carcasses with a blood-soup concentrate.

This sounds plausible on the surface, but instead it appears that the blood vessels in lysate are the ones closer to what would actually happen in the real world. Indeed, to quote the entire paragraph which Thomas pulls half a sentence from (bolding for emphasis; “HB” stands for haemoglobin):

An ostrich blood vessel model was used to determine post-mortem conditions, possibly contributing to preservation of tissues, as observed in the dinosaur samples. Ostrich vessels were incubated in a concentrated solution of red blood cell lysate (see the electronic supplementary material) to approximate post-mortem erythrocyte lysis. Control tissues were prepared identically, then incubated in either sterile distilled water or phosphate buffered saline (PBS). Haemoglobin was chosen to test its preservation properties for four reasons: (i) HB is in known to be bacteriostatic; (ii) in the presence of dioxygen, HB produces free radicals [65]; (iii) blood vessels fill with large amounts of HB after death as red cells begin to die and lyse, thus it is naturally present in large vertebrates; and (iv) haeme released from HB, when degraded, will release iron, possibly accounting for the iron particles associated with preserved soft tissues.

By incubating the blood vessels in lysate they preserve the haemoglobin that would normally remain in the tissues, while in distilled water this is lost.

Second, many of the still-fresh fossil biochemicals described in the literature do not show evidence of nearby iron. For example, researchers have encountered bone cells called osteocytes locked inside dinosaur bones, including a Triceratops horn core. These cells have fine, threadlike extensions that penetrate the bone’s mineral matrix through tiny tunnels called canaliculi. Could concentrated blood penetrate and preserve those almost inaccessible bone cells?

Thomas points to a paper published in Acta Histochemica in August by Mark Armitage and Kevin Lee Anderson, which appears to a be a legitimate case of a young Earth creationist getting published in the peer reviewed literature (apparently Armitage lost his job shortly afterwards, and to the creationists this of course means that he has been Expelled). Armitage doesn’t seem to have found any iron, but he also doesn’t seem to have looked.

Schweitzer and her coauthors think so. They wrote, “In life, blood cells rich in iron-containing HB [hemoglobin] flow through vessels, and have access to bone osteocytes through the lacuna-canalicular network.” Yet, the study authors did not demonstrate this supposed access, they merely asserted it.

In contrast, Schweitzer did look and did indeed find iron on the membranes of her osteocytes. While Thomas doesn’t want to believe that this is possible, the evidence shows that it did happen. What’s more, when Schweitzer “asserted” that blood cells have access to osteocytes she provided citations: Thomas appears to be denying a fact of anatomy, not a baseless claim.

For example, have experiments shown that canaliculi can wick blood puree, despite having tiny diameters on the order of 0.0004 millimeters? Also, how could iron-rich preservative “have access to” tiny tunnels already clogged with osteocytes? Other examples of original soft tissues without these iron particles include mummified dinosaur and lizard skin.

I was under the impression that small diameters was what wicks were all about…

Thomas’ examples of “soft tissues without these iron particles” is a 2010 paper that I have seen before which involves the notoriously stable pigment melanin, and a 2011 paper that I hadn’t but which provides an explanation for its preservation (and which did actually find some iron).

Moving along a bit:

Third, for experimental control, the Royal Society authors kept ostrich vessels in water to watch them rot. Does this resemble the burial conditions of dinosaurs, which are mostly dry today and have been primarily dry perhaps since the day of burial? Water accelerates tissue decay by providing for microbes and by facilitating degradative chemistry. So by adding water, these scientists may have rigged their “control” sample to show a higher-than-expected decay rate difference.

Dry from the day of burial? Don’t the creationists claim that everything was deposited in the (rather damp) Global Flood, and that wet layers of sediment explain folds in rock layers? Or am thinking of a different group?

The treated blood vessels were also in water, just water with stuff in it. Perhaps it would be useful to run another test which allowed things to dry out, but I doubt that we would see a recovery of a significant portion of the 24000% increase in preservation time that Thomas needs to erase. He claims that:

If both their control and test models used unrealistic conditions, then they dulled the edge of their entire argument.

But a dull blade is still dangerous, especially when you are in as precarious of a position as Brian Thomas. He has one final argument to make:

Fourth, just because this iron increases the “resistance of these ‘fixed’ biomolecules to enzymatic or microbial digestion” does not necessarily mean that it increases resistance of these “fixed” biomolecules to degrading chemical reactions. In other words, these authors have again shown that iron inhibits microbes, but they did not show that it inhibits the oxidation and hydrolysis reactions known to relentlessly convert tissues into dust.

Haemoglobin is already known to have antimicrobial properties, but to claim that iron cannot also aid the chemical preservation of the tissues is to ignore the results of the paper entirely. That was what this paper was all about.

Oxygen is known for oxidasing chemicals, and so aiding in their destruction. The blood vessels in distilled water were found, as you would expect, to degrade more when oxygen was present than when it was not. But in those treated with the lysate oxygen actually aided in preservation, even though there was no bacteria present regardless of how much oxygen there was. This and other evidence makes it abundantly clear that there is indeed defence from chemical degradation in action, despite what Thomas claims.

To sum up then, Thomas has numerous objections but nothing that is capable of landing a solid blow. The best he can do is, in effect, give pointers for future research. He is forced to concede that iron can indeed aid in preservation, as was predicted, but isn’t about to give up on his prized argument just yet. He concludes his article with an attempt to spin the results in a more positive direction:

By showing that iron particles stuck to dinosaur blood vessels look similar to those attached to ostrich vessels, this research may explain how soft tissues have resisted disintegration for longer-than-expected intervals—for example, thousands of years.

In other words he thinks that Schweitzer has shown that the cells could last as long as he needs them – despite not previously expressing any doubt that was possible – but not long enough for her purposes. At this rate Thomas wont be satisfied until Schweitzer invents a time machine to take her back to the Cretaceous and run her experiment for the full 70 million years.