Monday, August 3, 2015
Sunday, August 2, 2015
The theory does appear to offer a possible ways forward on the first front, although I'm not as sure about the second, but that's not my primary area and I'm fascinated by the chemical possibilities. Deacon's take on physical chemistry and the nature of energy is solid enough and unique enough that I'm considering how to teach it in my physical chemistry course. Much better than I could do on neuroscience (Deacon's primary area), that's for sure.
As Deacon admits, this book is only a sketch, albeit a 545-page sketch. I could have used more. Since dynamical processes have particular structures, I could have used more figures to clarify some of Deacon's terms and "levels" of dynamics. Although the evolution and mind subjects are interrelated, I think we could have gotten one book on evolution and a second book on mind, and that would have left room to explore more side roads and give more examples. But I'm intrigued enough to come up with examples on my own.
The biggest ally left unenlisted may be theology. Apophatic theology involves double negatives and absential qualities like Deacon's work. Again, this is an open door for others to walk through. I think there's fruitful progress to be made in taking Deacon's ideas seriously and then using those as a basis for natural theology (a la McGrath, not a la Paley, of course!).
In sum, this is a book that I've only begun to soak in. It already makes the short list of "10 most influential books" in my life.
* Deacon and RJP Williams do both emphasize constraints, so much so that I'm already seeing new things by juxtaposing the two. My first public reflection on Williams was a lecture titled "The Chemical Constraints on Creation" no less!
Wednesday, July 15, 2015
The Zalekskis weave a narrative from four strands that meet in mid-20th-century Oxford: J.R.R. Tolkien, C.S. Lewis, Owen Barfield, and Charles Williams. My book reviews include numerous examples of all of the above. Of these, Tolkien and Lewis are preeminent and the obvious draws. Barfield and Williams are the ones you discover because of their association with the better-known duo. Barfield's story is more active near the beginning and end (he lived until 1997!) and Williams only gathers the equivalent of a chapter or two in the middle, fitting with his firework-like entrance and exit.
The sharp-eyed reader will notice that a key part of this story is left out. Human and bacteria proteins have the same basic chemistry, being made of the same CHON atoms. If bismuth is sticky to bacterial proteins, it must be just about as sticky to human proteins. So if bismuth kills bacteria, it should kill human cells as well. So why is it that we can drink the stuff? Why is there a novel titled Arsenic and Old Lace but Bismuth and Old Lace doesn't scare anyone?
Human cells can survive a dose of Pepto because they have an extra layer of chemical protection. Our internal chemical shield is built from sulfur, in the form of the molecule glutathione, mentioned in another part of Chapter 2. How this shield works is shown in a 2015 PNAS paper titled "Glutathione and multidrug resistance protein transporter mediate a self-propelled disposal of bismuth in human cells" (which, incidentally, is so well done that other scientists would do well to pattern their metal-life investigations on it).
As shown in the diagram above, purple bismuth (Bi) approaches from the left. It crosses the cell membrane and sticks to yellow glutathione's (GSH's) sulfur atoms. Bismuth is so sticky it collects multiple glutathiones, then the cell takes the assembly and tucks the dangerous metal away into a small sulfurous bubble (or vacuole) shown in gray on the right. This is what glutathione is for -- to preemptively stick to the sticky things before they can stick to something else.
The really nifty part of this is that as this process depletes glutathione, the cell senses that and turns on the machinery for making more glutathione. The more bismuth abounds, the more glutathione super-abounds to fix it. Excess glutathione is then available for sticking to other toxic metals as well, so that Pepto may incite a more general protection.
The bacteria killed by Pepto-Bismol don't have a complex glutathione system like this, so its stickiness turns their insides to solids, and they die. Human cells can resist internal petrification because of the chemistry of sulfur as corralled by glutathione's structure. Our cells sweep the sticky bismuth into a side chamber and our proteins remain nice and fluid.
This has implications for cancer therapy. Some forms of chemotherapy kill cancer cells with sticky, toxic metals like platinum. Cancer cells resist the chemo by turning up their glutathione production. Understanding how that system works should allow us to find a way to turn it off, which would make metal-based chemo much more effective. More details can be found in this summary article related to the research article above.
This is also why understanding the chemistry is so helpful. Bismuth-sulfur chemistry may lead to more effective chemo. So support your neighborhood chemist -- you never know what she'll find next.
Friday, July 10, 2015
This expands on the narrative of A World From Dust in two important ways:
1.) The problem with being warm-blooded is not just making the heat, but keeping it. To insulate its precious heat from the cold waters around it, the opah pumps its blood through intricate and efficient blood vessels in twisted hairpin shapes. This structure is called a rete mirabile and can be built using Adrian Bejan's engineering theories for how heat flows. This hairpin structure is optimal for insulating a circulating fluid, so it is found repeatedly in warm-blooded animals. Bejan's Constructal Law could have been used to predict that a warm-blooded fish would have a complex rete mirabile structure before that structure was found in the fish -- it is a consequence of how heat moves. The opah is generating more heat, so I believe it would have a higher Energy Rate Density and Chaisson's ideas may apply, too. It has a more complex internal structure to match its higher energy throughput.
2.) Other fish that look like the opah and have genes like the opah are not warm-blooded, but a few very different fish (for example, tunas and lamnid sharks) have the biological spaceheaters that are halfway there. These fish obviously have different shapes and different genes, but they have independently developed similar systems for heat generation and insulation. In very different species, evolution has converged to produce similar and predictable warm-blooded temperatures and structures. Which species get it may depend on random rolls of the dice at the gene level, but that some species will get it and fluorish, that is predictable, given enough time.
So, not only is a warm-blooded fish very cool (see what I did there?), it also shows that evolution solves similar problems with similar features (warm blood) and similar structures (rete mirabile), in tuna, lamnid sharks, and opah, repeatedly producing predictable complexity.
Note: The audiobook reader is really excellent, changing tones to indicate different characters artfully, and throwing himself into King's over-the-top dialogue with gusto. I recommend listening to this rather than reading it.