Killer Cellphones Destroy Bees

 
Friday's Urban Legend: Probably FALSE

An article in our local newspaper (The Toronto Star) suggests a link between the mass kill off of bees and cellular phones [Cellular phone uses linked to bee deaths]. A similar report appeared in The Independent in the UK [ Are mobile phones wiping out our bees?].

Here's the problem. There are reports in Canada and the United States of disappearing honey bees. Apparently, entire colonies are being abandoned. The phenomenon is somewhat localized. In Canada, for example, excessive bee loss is only reported in central British Columbia and the Niagara peninsula in Ontario. The phenomenon is called colony collapse disorder.

If the bee disappeared off the surface of the globe, then man would only have four years of life left.
.... Albert Einstein

This quote appears in several newspaper articles and on many blogs. Snopes is on to it and so far there's no proof that Einstein ever said this [Einstein on bees].We are told that "German researchers" have linked cellphone radiation to the disappearance of bees. The business reporter checked with Martin Weatherall to see if this is correct. Who is Martin Weatherall, you might ask?

Weatherall, a retired Toronto police officer who was forced out of his Woodstock, Ont., home after high levels of radio waves from nearby hydro-electric poles and cellphone towers made him electro-hypersensitive, is better able than most to understand the German study, which shows that bees refuse to return to their hive when cellphones are placed nearby.

Near the end of the story in the Toronto Star the reporter also checks with Ernesto Guzman, an expert on bees at the University of Guelph in Ontarion, Canada. Guelph is one of the top schools in veterinary medicine and agriculture.

Despite the new German research, bee researchers remain skeptical of the impact of radio waves on bees. They claim it is just one of several theories that include global warming and genetically modified crops.

"All of these are speculation. They deserve to be investigated. They are good hypotheses, some of them. Others are out of reality, in my opinion," said Ernesto Guzman, associate professor with the University of Guelph's department of environmental biology.

Guzman, a specialist in bee research, says he believes stress is the major factor in the situation south of the border while in Canada a combination of poor weather on fall food supply levels and an influx of mites is the likely cause.

Personally, I will take Guzman's word over that of a retired police officer suffering from "electro-sensitivity." If I were writing the headline it would be "Cellphone link to bee deaths discredited by expert." I guess it all depends on how you want to frame spin the article.

Orzel Is Confused

 
On his blog Uncertain Principles, Chad Orzel posted on "framing" [The Final Word on Framing. He said,

That's a thought, but I think the answer is much simpler: PZ and Larry Moran are not primarily interested in promoting science.

"That's crazy," you say. But here it is from the horse's mouth, Larry Moran in Chris Mooney's comments:

I think religion is the problem and I'll continue to make the case against religion and superstition. One of the many ways where you and Nisbet go wrong is to assume that people like PZ, Dawkins, and me are primarily fighting for evolution. That's why you argue that in the fight to save evolution it's "wrong" (e.g., not part of your frame) to attack religion.

When are you going to realize that our primary goal in many cases is to combat the worst faults of religion? Asking us to stop criticizing religion is like asking us to give up fighting for something we really care about. That's not "framing," it's surrender.

That's the beginning and end of the problem. The entire problem with "framing" is that Nisbet and Mooney are looking for the best way to promote science, while PZ and Larry are looking for the best way to smash religion. The goals are not the same, and the appropriate methods are not the same-- in particular, Nisbet and Mooney argue that the best way to promote science would be to show a little tact when dealing with religious people, and that runs directly counter to the real goals of PZ and Larry.

It's not a simple as that Chad. I try to do both things. I try to write about science with the hope that I'm telling people something they don't know. If you would take the time to look at my blog I think you might see the occasional posting on science-related topics. Religion isn't mentioned.

On the other hand, there are times when I post about the conflict between rationality and superstition. I think there's a problem there and religion is a big part of it. Quite frankly, I don't find the arguments of the Theistic Evolutionists the least bit effective. Why should I ignore them when they spout their silliness?

Telling me that I should not criticize religion because it's not helping science education is just nonsense. It's like telling me to abandon something I feel very strongly about just because you don't like it. If that's what framing is all about then I'm not interested.

The problem with the framers is that they get terribly confused about issues. For some reason they think I'm a one dimensional person who's only interest is science education. They think that when I criticize superstitious nonsense I must always be wearing my science education hat. That's why they tell me and Dawkins and PZ not to criticize religion if we're trying to educate people about science.

Well, I got news for them. We are involved in several issues. One of them is teaching science. One of them is fighting superstition. There are others. Don't tell me not to fight superstition because I should only be concerned about science education. I'm concerned about both. In an ideal world people would understand science and reject superstition. I'd like to work toward that goal.

New Ways of Looking at Evolution

 
John Logsdon over at Sex, Genes, and Evolution recommends a new book, The Origins of Genome Architecture by Michael Lynch. John also points us to a review article by Lynch [The Origins of Eukaryotic Gene Structure]. I second both recommendations. Read the article. Buy the book.

Here's a quotation from the article by Lynch,

Despite the enormous progress in molecular genetics over the past 50 years, no general theory for the evolution of the basic architectural features of genes has been formulated. Many attempts have been made to explain the features of genes, genomes, and genetic networks in the context of putatively adaptive cellular and/or developmental features, but few of these efforts have been accompanied by a formal evolutionary analysis. Because evolution is a population-level process, any theory for the origins of the genetic machinery must ultimately be consistent with basic population-genetic mechanisms. However, because natural selection is just one of several forces contributing to the evolutionary process, an uncritical reliance on adaptive Darwinian mechanisms to explain all aspects of organismal diversity is not greatly different than invoking an intelligent designer.

Some of you will probably see why I like this guy! He warns against "uncritical reliance on adaptive Darwinian mechanisms."

This paper represents a first step toward the formal development of a general theory for the evolution of the gene that incorporates the universal properties of random genetic drift and mutation pressure. Although the ideas presented are unlikely to be correct in every detail, at a minimum they serve as a null model. For if verbal adaptive arguments are to provide confident explanations for any aspect of gene or genomic structure, something must be known about patterns expected in the absence of selection. This is a significant challenge because at this point it is difficult to reject the hypothesis that the basic embellishments of the eukaryotic gene originated largely as a consequence of nonadaptive processes operating contrary to the expected direction of natural selection. A significant area of future research will be to take these observations on gene and genome complexity to the next level, to evaluate whether natural selection is a necessary and/or sufficient force to explain the evolution of the cellular and developmental complexities of eukaryotes.

Everyone needs to start paying attention. Random genetic drift is just as important for evolution as natural selection. That's not speculation. As far as I'm concerned, it's hard incontrovertible fact.

One of the "new ways" of looking at evolution is to consider mutation pressure, loosely defined as differences in the frequency of mutation. I'm not a big fan of this but it does emphasize that modern evolutionary theorists are thinking outside the Darwinian box—not surprising since Darwin died 125 years ago (today). I prefer mutationism, which is a way of emphasizing the imprtant role of mutation in directing evolution. Mutationism and mutation pressure are not the same thing.

Haldane's Dilemma

This is very interesting. Dembski has teamed up with Walter ReMine, demonstrating once again that the old addage "opposites attract" does not apply to kooks.

ReMine has an article on Uncommon Descent where he pushes his usual whine about evil scientists and how their world-wide conspiracy has kept him from revealing the fatal flaw in evolution [Evolutionist withholds evidence on Haldane’s Dilemma]. I can see how similar this is to Intelligent Design Creationism.

Some of you may not be familiar with the so-called "dilemma" of Haldane. Fortunately, ReMine provides a nice short summary.

For many years I have publicly claimed Haldane’s Dilemma is a major unsolved problem for evolution. A problem so severe it threatens macroevolution as a “fact” and evolutionary genetics as an empirical science. The problem, briefly, is that evolutionary geneticist, J.B.S. Haldane (1957), discovered an important argument that limits the speed of evolution. Under his calculations, an ape-human-like population, given a generous ten million years, could substitute no more than 1,667 beneficial mutations — which, according to evolutionary geneticists, are each typically a single nucleotide. All the human adaptations within that time would have to be explained with this small number of substitutions. For more information, see here: Haldane's Dilemma.

That's it. Fifty years ago J.B.S. Haldane did a quick calculation suggesting that if you make certain assumptions (now shown to be inaccurate) then you could only fix 1,667 beneficial human mutations in 10 million years. Apparently ReMine thinks this is way too little evolving, even if all it has to do is produce the likes of him and Dembski.

We don't need to thrash out why ReMine is wrong. That's been done many times. What's interesting about this is the Wikipedia article that ReMine wrote. Go there right now and take a look because it won't look like that for long now that ReMine has let the cat out of the bag. Oops! It's not on Wikipedia it's on another Wiki called ResearchID.org. My goof—thanks to Torbjörn Larsson for pointing this out. The real Wikipedia article [Haldane's dilemma] is pretty good. So now the only reason for taking note of this is the fact that ReMine is being promoted by Dembski. That's hardly news. Move along. There's nothing to see here.

For all you talk.origins fans, I found a little bit of history when I did the research for this article. Follow this link to a message from Saint Andrew (you know who that is). It's about a 1995 post from Ted Holden (yes, the famous Ted Holden who coined the term "Howler monkeys") defending Walter ReMine. Proving once again that kooks will recognize each other.

The picture of ReMine is from the video of a lecture on his book The Biotic Message. You can only watch a few minutes but that's enough. He does a fine job of spining "framing" his message for an audience of true believers.

[If you mention his name, he will come.]

Charles Darwin Died in 1882

 
In honor of Charles Darwin, who died on this day, I'm posting the opening paragraphs of a manuscript that might eventually be a book called Evolution by Accident.

I approached Westminster Abbey from the south side, crossing Abingdon Street in front of the Houses of Parliament. There was a long line of tourists in front of the ticket window and, not wanting to waste a beautiful Spring day, I decided to do a bit of exploring before joining the queue.

An old three story building caught my eye. It was the Jewel Tower, built 650 years ago to house the treasures of King Edward III. The Jewel Tower is all that remains of the medieval Palace of Westminster that was mostly destroyed by fire in 1834. The Houses of Parliament and Big Ben off to my left were built to replace the original palace—they look old but they have "only" been there for 175 years.

Going behind the Jewel Tower I spot the remains of the old moat and walls that used to surround Westminster Palace. They don’t serve any purpose now since they are well below ground level and, besides, Abingdon Street cuts right through the place where the wall and moat used to protect the old palace buildings.

I cross the street by Victoria Tower at the south-west corner of the Houses of Parliament and enter Victoria Tower Gardens. According to the medieval map in the Jewel Tower, this used to be in the middle of the Thames and there was a quay for loading and unloading boats along the edge of the palace where Victoria Tower now stands. The park is quiet and peaceful at this time of day. I imagine it gets more traffic at lunch time. The Thames is also quiet, but muddy. I watch a family of ducks swim by.

The object of my pilgrimage was inside Westminster Abbey and it was time to return to the entrance. Fortunately, the long line had dissipated and I was able to purchase my ticket (£2) after a short wait. The designated route takes you through the Great North Door where you enter the Transept. Turning left, I follow the other tourists as we are herded around the back of the Abbey through the rooms behind the alter. We pass the tombs of Queen Mary the First (1516-1558), Queen Elizabeth the First (1533-1603), and Mary, Queen of Scots (1542-1587) in the Lady Chapel. We stop to admire the shrine of Saint Edward the Confessor (1002-1066).

I’m getting impatient but I can’t move any faster because of the crowd of tourists. Eventually we wind around the Monastery and finally enter the Nave. Ignoring the monument to Winston Churchill (1874-1965) and hardly bothering to look up and admire the high ceiling, I head for the back left corner where I can see the statue of Isaac Newton (1643-1727). This is the same statue that plays such an important role in the Da Vinci Code but today I’m not interested in Newton or his orb. It takes me only a few seconds to find the marked stone on the floor. I’m standing on the grave of Charles Robert Darwin.

I can picture the scene on Wednesday, April 26, 1882—a grand funeral attended by all of London’s high society and the leading intellectuals of the most powerful nation in the world. Darwin would not have been pleased. He wanted to be buried quietly in the Downe cemetery with his brother Erasmus and two of his children. Darwin's family was persuaded by his friends Galton, Hooker, Huxley and the President of the Royal Society, William Spottiswoode, that, for the sake of England, Darwin should be laid to rest in Westminster Abbey. As Janet Browne writes in her biography of Charles Darwin, "Dying was the most political thing Darwin could have done."²

Looking around I can see the tombs of two of the scientists who were Darwin’s pallbearers, Joseph Hooker and Alfred Wallace. (Another pallbearer, Thomas Henry Huxley, is buried elsewhere.) Nearby are the final resting places of a host of famous scientists; Kelvin, Joule, Clerk-Maxwell, Faraday, Herschell, and Sir Charles Lyell. (Lyell was Darwin’s hero and mentor. We are told that Darwin’s wife Emma wished he were buried closer to Lyell.)

I am not overly sentimental but this visit has a powerful effect. I think Charles Darwin is the greatest scientist who ever lived—yes, even greater than Sir Isaac Newton whose huge statue overshadows Darwin’s humble marker in the floor. Natural selection is one of the greatest scientific ideas of all time. Darwin discovered it and he deserves enormous praise for his achievement. But Charles Darwin died on April 19, 1882 and that was a long time ago.

Temple Universit Students Respond

 
Last week I posted an article about Intelligent Design Creationists giving a talk at Temple University. I wondered what the students must have been thinking to invite two Young Earth Creationists (Marcus Ross, Paul Nelson) to come and talk to them as part of a series entitled: DECIDE FOR YOURSELF: Evolution and Intelligent Design.

Two Temple University students who attended the event have now responded. Both choose to remain anonymous. You can read their comments at [Marcus Ross, Michael Behe, and Paul Nelson at Temple University].

Here are some teasers ..

To start, your judgmental and self-righteous words have proven to me that your whole position is without credibility as you refused to attend Temple's event.

and .....

Because you chose not to participate, is it really right to take potshots at students from the web? Are you in a superior position professionally, educationally, or morally to condemn the students and therefore the other professional educators under whose approval and encouragement the students are working? Your intolerant conceit is more disagreeable than the students' supposed ignorance.

Gee, I wonder what they "decided for themselves" at the lectures? Anyone wanna take a wild guess?

Nobel Laureate: Aaron Klug

 

The Nobel Prize in Chemistry 1982.



Aaron Klug (1926- ): "for his development of crystallographic electron microscopy and his structural elucidation of biologically important nucleic acid-protein complexes"

Aaron Klug won the Nobel Prize in 1982 for his work on a special technique for solving the structures of large molecules that can't be crystallized. He used it to determine the structure of the nucleosome. Here's how Klug's contribution is described in the presentation speech.

Large molecular aggregates can seldom be obtained in a form which allows structural determination by X-ray diffraction. The investigator who has been awarded with this year's Nobel Prize in chemistry, Aaron Klug, has developed a method to study the structure of molecular aggregates from biological systems. His technique is based on an ingenious combination of electron microscopy with principles taken from diffraction methods. Electron microscopy has long been used to depict the structural components of the cell, but its power of resolution is after, limited by a lack of contrast in the picture. Klug has shown that even picture; seemingly lacking in contrast may contain a large amount of structural information, which can be made available by a mathematical manipulation of the picture.

With this technique, in combination with other methods of structural chemistry, Klug has inter alia investigated viruses and chromatin of the cell nucleus. His virus studies have illuminated an important biochemical principle, according to which the complicated molecular aggregates in the cell are formed spontaneously from their components. The chromatin investigations have provided clues to the structural control of the reading of the genetic message in DNA. In a long-term perspective they will undoubtedly be of crucial importance for our understanding of the nature of cancer, in which the control of the growth and division of cells by the genetic material no longer functions.

Klug started working on tobacco mosaic virus in 1954 when be began a collaboration with Rosalind Franklin who had just abandoned DNA. Klug and Franklin remained close associates until she died a few years later.

Klug solved the structure of TMV using X-ray diffraction but this proved inadequate for other large structures. In order to solve the structures of more complex viruses (e.g., bacteriophage T4) and chromatin, Klug turned to high resolution electron microscopy. He developed techniques for assembling and refining multiple images with the aid of complex computer programs. Basically, he was able to solve the three dimensional shape using multiple two dimensional images as shown in the diagram (right) from his Nobel Lecture.

Klug's work has been modified an improved over the years. Today the electron microscopic images are much better and special low temperature electron microscopes (cryo-EM) can be used to obain images from material that would be destroyed at normal temperature. The enormous increase in computing power and modern software have led to the solution of many complex structures such as the pyruvate dehydrogenase complex.

The Structure of the Pyruvate Dehydrogenase Complex

 
The pyruvate dehydrogenase complex catalyzes the reaction that converts pyruvate to acetyl-CoA with the release of CO₂. The reaction is coupled to the reduction of NAD⁺ to NADH₂ [Pyruvate Dehydrogenase Reaction]. The three components of the complex, E₁, E₂, and E₃ catalyze different steps.

The size of the pyruvate dehydrogenase complex is enormous. It is several times bigger than a ribosome. In bacteria these complexes are located in the cytosol and in eukaryotic cells they are found in the mitochondrial matrix. Pyruvate dehydrogenase complexes are also present in chloroplasts.

The eukaryotic pyruvate dehydrogenase complex is the largest multienzyme complex known. The core of the complex is formed from 60 E2 subunits arranged in the shape of a pentagonal dodecahedron (12 pentagons joined at their edges to form a ball). This shape has 20 vertices and each vertex is occupied by an E2 trimer. Each of the E2 subunits has a linker region projecting upward from the surface. This linker contacts an outer ring of E1 subunits that surround the inner core. The linker region contains the lipoamide swinging arm.

The outer shell has 60 E1 subunits. Each E1 enzyme contacts one of the underlying E2 enzymes and makes additional contacts with its neighbors. The E1 enzyme consists of two α subunits and two β subunits (α2β2) so it is considerably larger than the E2 enzyme of the core. The E3 enzyme (an α2 dimer) lies in the center of the pentagon formed by the core E2 enzymes. There are 12 E3 enzymes in the complete complex corresponding to the 12 pentagons in the pentagonal dodecahedron shape. In eukaryotes, the E3 enzymes are associated with a small binding protein (BP) that’s part of the complex.

The model shown above has been constructed from high resolution electron microscopy images of pyruvate dehydrogenase complexes at low temperature (cryo-EM) (below). In this technique, a large number of individual images are combined and a three-dimensional image is built with the help of a computer. The model is then matched with the structures of any of the individual subunits that have been solved by X-ray crystallography or NMR.

A similar pyruvate dehydrogenase complex is present in many species of bacteria although some, such as gram negative bacteria, have a smaller version where there are only 24 E2 enzymes in the core. In these bacteria, the core enzymes are arranged as a cube with one trimer at each of the 8 vertices. The E2 subunits of the two different bacterial enzymes and the eukaryotic mitochondrial and chloroplast versions are all closely related. However, the gram negative bacterial enzymes contain E1 enzymes that are unrelated to the eukaryotic versions.

So far, it has not been possible to grow large crystals of the entire pyruvate dehydrogenase complex on Earth. Experiments were undertaken to grow crystals on the International Space Station where the absence of gravity might have led to better results. Unfortunately, none of the esperiments were successful so, for the time being, the best model of the pyruvate dehydrogenase complex is the one constructed from the cryo-EM images.


[This is a slightly modified version of material in Horton et al. (2006) Principles of Biochemistry 4th ed.©L.A. Moran and Pearson/Prentice Hall]

Pyruvate Dehydrogenase Reaction

 
Pyruvate dehydrogenase catalyzes the conversion of pyruvate to acetyl-Coenzyme A (acetyl-CoA). The reaction is coupled to the reduction of NAD⁺ to NADH. The reaction is an example of an oxidative decarboxylation since the other product is carbon dioxide (CO₂). [Pyruvate] [Fritz Lipmann and Coenzyme A]

Acetyl-CoA is subsequently used up in the citric acid cycle and in fatty acid synthesis.

This is a very complicated reaction. It turns out that the enzyme pyruvate dehydrogenase is actually a complex of several different activities. From now on I'll refer to it as the pyruvate dehydrogenase complex (PDC).

The first step in the reaction is the decarboxylation step and it requires a special cofactor called thiamine pyrophosphate (TPP). This is vitamin B₁ and it explains why that vitamin is essential. Carbon dioxide is released in this step and the remaining 2-carbon fragment of pyruvate is attached to TPP. This part of the reaction is catalyzed by a part of PDC composed of E₁ subunits.

In the next step, the 2-carbon fragment is transferred to a "swinging arm" composed of a lipid arm (blue zigzag) and a head containing two sulfur (S) atoms. The swinging arm actually swings to carry the red acetyl group from one active site in the complex to another. The second site is where the acetyl group is attached to CoA. This part of the reaction is carried out by the E₂ subunits in the complex.

The swinging arm carries excess electrons from the previous reaction in the form of two -SH groups. The next site visited by the swinging arm is the site where electrons are passed to another cofactor called FAD. This is the dihydrolipoamide dehydrogenase activity and it's the E₃ subunits that do the job. Electrons are then passed from FADH₂ to NAD⁺ to produce NADH₂.

The complete reaction is a classic example of an electron transport chain involving three groups: the lipoamide head of the swinging arm, FAD, and NAD⁺. In the next article we'll look at the structure of the pyruvate dehydrogenase complex. It's one of the largest multienzyme complexes found in living cells.

Recourse to the Miraculous is Always a Regressive, Obfuscating Move

 
The same issue of Skeptical Inquirer that contained the Michael Ruse article [Appeasers and Other Atheists] also has an article by Frederick Crews.

Crews, F. (2007) Follies of the Wise. Skeptical Inquirer March/April 2007 pp.27-31.

Crews addresses the same issue as Ruse; namely whether it's a good idea to distinguish between Intelligent Design Creationists and Theistic Evolutionists. However, he delves deeper into the issue that Ruse does. I'm tempted to say that Crews is being more scholarly than Ruse.

Whenever we (e.g., PZ, Dawkins etc.) try to make the case that Theistic Evolution is just as fuzzy-headed as Intelligent Design Creationism we are accused of over-stepping the limits of science. While everyone recognizes that scientists must practice methodological naturalism, there seem to be lots of people who don't know what that is. They seem to think that it's okay to believe in miracles and still brag about being scientific. I've tried to point out the inconsistencies in such a position in my essay [Theistic Evolution: The Fallacy of the Middle Ground]. As Crews says below, "recourse to the miraculous is always a regressive, obfuscating move." This applies to Intelligent Design Creationism of course, but it also applies to the Theistic Evolution of Ken Miller, Francis Collins, and Simon Conway-Morris. I just don't see how atheists can dismiss the miracles of Dembski, Denton, and Behe while accommodating the miracles of Miller, Collins, and Conway-Morris. That makes no sense to me.

Crews takes a different approach. He argues that metaphysical naturalism is a valid and rational extension of methodological naturalism. This is contrary to Ruse and to the people at NCSE (e.g., Eugenie Scott). I present the Crews argument below. Let me know what you think. Personally I agree with him, even though I'm prepared to argue that most of the so-called "science" in books by Theistic Evolutionists is in violation of methodological naturalism not just metaphysical naturalism.

... some scientists and philosophers who are privately indifferent or hostile to transcendent claims nevertheless seek an accommodation with them. They do so from the best of motives, in order to stem the infiltration of bumpkin "creation science" or its slick city cousin "intelligent design," into biology curricula. Their hope is to show that scientific research and education have no bearing on issues of ultimate meaning and hence needn't be feared by the pious. To that end, they emphasize that science exemplifies only methodological naturalism, whereby technical reasons alone are cited for excluding nonmaterial factors from reasoning about causes and effects. Hence, they insist, the practice of science doesn't entail metaphysical naturalism, or the atheist's claim that spiritual causation is not only inadmissible but altogether unreal.

In one sense this is an impregnable argument. Even when science is conducted by ardent believers, it has to disregard theological claims because those claims typically entail no unambiguous, real-world implications, much less quantitative ones, that might be tested for their supportive or falsifying weight. The allegation that God was responsible for a given natural fact can't be either established or refuted by any finding; it is simply devoid of scientific interest. And thus it is true enough that scientists stand under no logical compulsion to profess metaphysical naturalism.

Any God worthy of the name has to be capable of miracles, and each of the great Western religions attributes a number of very special miracles to their conception of God. What can science say about a miracle? Nothing. By definition, the miraculous is beyond explanation, beyond our understanding, beyond science.

Ken Miller in "Finding Darwin's God" p. 239Quite obviously, however, trust in the supernatural does get shaken by the overall advancement of science. This is an effect not of strict logic, but of an irreversible shrinkage in mystery's terrain. Ever since Darwin forged an exit from the previously airtight argument of design, the accumulation of corroborated materialist explanations has left the theologian's "God of the gaps" with less and less to do. An acquaintance with scientific laws and their uniform application is hardly compatible with faith-based tales about walking on water, a casting out of devils,and resurrection of the dead.

Metaphysical naturalism may be undiplomatic, but it is favored by the totality of evidence at hand. Only a secular Darwinian perspective, I believe, can make general sense of humankind and its works. Our species appears to have constituted an adaptive experiment in the partial and imperfect substitution of culture for instinct, with all the liability to self-deception and fanaticism that such an experiment involves. We chronically strain against our animality by inhabiting self-fashioned webs of significance—myths, theologies, theories—that are more likely than not to generate illusory and often murderous "wisdom." That is the price we pay for the same faculty of abstraction and pattern drawing that enables us to be not mere occupiers of an ecological niche but planners, explorers, and, yes, scientists, who can piece together facts about our world and our own emergence and makeup.

Here it may be objected that myths, theologies, and theories themselves, as nonmaterial things that can nevertheless set in motion great social movements and collisions of armies, confound a materialist or metaphysically naturalist perspective. Not at all. We materialists don't deny the force of ideas; we merely say that the minds precipitating them are wholly situated within brains that, like everything else about which we possess some fairly dependable information, seem to have emerged without any need for miracles. Although it is not a provable point, it is a necessary aid to clear thought, because now that scientific rationality has conclusively shown its formidable explanatory power, recourse to the miraculous is always a regressive, obfuscating move.

Pyruvate

Pyruvate is a very important molecule in living cells. It was Monday's Molecule #22. It's important because it's one of the essential 3-carbon (3C) intermediates in biochemical pathways. It's required in both biosynthesis and degradation pathways. If you only have to know a few molecules in the cell then this one should be near the top of your list.

Let's start by learning a little bit of organic chemistry. The simplest organic molecule with only two carbon atoms is called ethane (CH₃CH₃). The one with three carbons is propane and the one with four is butane. The alcohols are called ethanol, propanol, and butanol respectively. The acids are ethanoic acid (CH₃COOH), propanoic acid (CH₃CH₂COOH), and butanoic acid (CH₃CH₂CH₂COOH). Ethanoic acid is more commonly known as acetic acid because it's found in vinegar and the Latin word for vinegar is acetum.

Pyruvate can also be called pyruvic acid. In a minute I'll explain why we call it pyruvate instead. It's related to propanoic acid (CH₃CH₂COOH) except that it has an extra oxygen on the middle carbon. The -C=O group is called a keto group and molecules that have it are ketones.

The proper chemical name for pyruvate is 2-oxopropanoic acid because it's propanoic acid with an extra oxygen (oxo-) on carbon atom #2. Keto acids usually have trivial names that aren't related to the names of the simple organic molecules and that's why pyruvate is the name everyone uses. The reason why keto acids are common in biochemistry is because they are quite reactive.

Acids are compounds that can easily give up a proton (H⁺). Protons are what makes an acid an acid. The more protons you have in solution the more acidic the solution will be. The term pH refers to the inverse of the concentration of H⁺. The lower the pH the higher the concentration of protons.

Pyruvic acid is an acid because when it's dissolved in water the proton from the carboxylate (-COOH) group dissociates leaving the negatively charged pyruvate and a free proton. The three components exist in equilibrium—that's what the double arrows mean. At any given time there will always be some pyruvic acid, some pyruvate, and some protons. The concentrations won't change because the dissociation/association reactions are at equilibrium.

The relative concentrations of pyruvic acid and pyruvate at equilibrium depend on the properties of the molecule and the conditions inside the cell. In this particular case we know for certain that there's very little pyruvic acid inside the cell. Almost all of the molecules are in the form of pyruvate. Pyruvate is the biologically significant molecule and that's why biochemists always refer to these molecules as acetate, pyruvate, butyrate, etc.

In all species, pyruvate is required for the synthesis of the amino acid alanine. It's also required for the synthesis of 6-carbon (6C) sugars such as glucose. In fact, you can think of gluconeogenesis (glucose synthesis) as just a series of steps where two pyruvate molecules are joined to make one glucose molecule (3C + 3C → 6C).

Pyruvate itself is synthesized from simpler molecules in bacteria. One common pathway is to add a carbon from carbon dioxide to a 2-carbon acetate molecule (1C + 2C → 3C). In plants and bacteria the primary product of the carbon fixing cycle (Calvin cycle) is a 3-carbon compound called glyceraldehyde 3-phosphate. It is rapidly converted to pyruvate.

Pyruvate can be activated to a phosphorylated derivative called phosphoenolpyruvate (PEP). PEP is a high energy compound used as an energy source in many reactions. (It has considerably more energy than ATP.) The direct conversion shown in the diagram below is confined to bacteria. In eukaryotes the conversion follows an indirect pathway.

There are many other fates of pyruvate as shown above. Pathways leading to synthesis of additional amino acids go through oxaloacetate. Oxaloacetate is also one of the components of the citric acid cycle. The synthesis of lipids and fatty acids requires acetyl-coenzyme A or acetyl-CoA, which is made from pyruvate in a reaction catalyzed by pyruvate dehydrogenase (more about this later—it's the main theme of this series).

Most students first encounter pyruvate as the end product of glycolysis. Glycolysis is the pathway for breaking down glucose. It is the opposite of gluconeogenesis because a 6-carbon compound is degraded to two 2-carbon compounds (6C → 3C + 3C). Even though this is a minor pathway in most kingdoms, it is important in animals and, most especially, in mammals like us. This is why glycolysis has traditionally received so much attention in schools. That's about to change.

In some species the accumulation of pyruvate leads to other pathways. One of them is synthesis of lactate, which often serves as a temporary storage depot for 3-carbon compounds. Another is synthesis of ethanol, which involves chopping off one of the carbons in the form of carbon dioxide (CO₂) and excretion of ethanol. Humans love those species that excrete ethanol. Over several millennia humans have selected strains of yeast that do a very efficient job.

Nobody needs to memorize all the pathways involving pyruvate. Not even my biochemistry students. The point here is simply to illustrate the central importance of pyruvate so you'll see why it's something you should know about.

Of all the fates of pyruvate, the one that is most interesting is the conversion to acetyl-CoA. As mentioned above, acetyl-CoA is required for fatty acid synthesis but it also serves as the substrate for the citric acid cycle where the acetate part of pyruvate is fully oxidized to CO₂. Note that the reaction catalyzed by pyruvate dehydrogenase not only makes acetyl-CoA but also accomplishes the first step in the complete oxidation of pyruvate to 3 molecules of CO₂. The energy released in this breakdown is captured by NADH.

Dicumarol and Warfarin Inhibit Blood Clotting

 
Many of the blood coagulation factors are post-translationally modified in various ways. One of these modifications is unusual and it is only seen in these factors and a few other specialized proteins. This modification converts a specific glutamyl side chain to a γ-carboxyglutamyl derivative [Vitamin K].

The carboxylation reaction is catalyzed by vitamin K-dependent carboxylase and it is coupled to the conversion of vitamin K to its oxidized form. In order for the enzyme to modify additional factors, the oxidized form of vitamin K has to be converted back to the reduced form. Recall that vitamin K is an essential vitamin in animals. It can be obtained from plants or from intestinal bacteria.

Recycling of vitamin K is catalyzed by K reductase. The mechanism involves oxidation of two sulfhydryl (-SH groups) to form a disulphide bridge [Disulfide Bridges]. The carboxlase and reductase reactions are required for synthesis of prothrombin, protein C, Protein S, and Factors VII, IX, and X because these proteins must bind C²⁺ and the γ-carboxyglutamyl group is an excellent cheator of Ca²⁺.

A vitamin K deficiency means that the carboxylation reaction cannot proceed and this leads to accumulation of inactive clotting factors in the liver. Blood clots cannot form and severe hemorraging can lead to death.

The carboxylation of clotting factors can also be prevented by inhibiting the K reductase reaction. There are many drugs that inhibit this reaction. They are related to warfarin (left) [Monday's Molecule #19]. The best known ones are dicoumarol and coumarin. These drigs, especially warfarin, are used frequently to prevent clotting in patients who have suffered a stroke or otherwise have tendencies to exhibit thrombosis.

Since the drugs prevent synthesis of clotting fators, they take a few days to have an effect. They are usually administerd with heparin, which has an immediate effect on blood clot formation.

Wafarin was a common rat poison in the past since rats are very sensitive to inhibition of K reductase. After eating food laced with wafarin for several days, the rats would die of internal bleeding.

Appeasers and Other Atheists

 
Professors are under a lot of pressure. We have certain images that we need to cultivate in order to stay in the club. One of them is the image of a messy, disorganized, eccentric. I've got that one down pat.

I have four piles of reading material. There's the one on my bedside table for reading at night when I should be sleeping. There's a stack of papers and articles in my shoulder bag that I'm supposed to read on the train and subway. There are books on my desk at home and there's a huge pile of things on the desk in my office.

Since I started blogging, none of these piles are getting smaller.

Last night I finally got around to reading an article by Michael Ruse in the current issue of Skeptical Inquirer.

Ruse, M. (2007) Fighting the Fundamenalists: Chamberlain or Churchill? Skeptical Inquirer March/April 2007:38-41.

This is one of many articles in this special issue devoted to "Science, God, and (non)Belief."

Perhaps if I'd read the article sooner I might have anticipated the stance that Nisbet and Mooney would take in the framing debate. I actually thought the appeasers had learned their lesson. I thought they discovered last Fall that they can't stifle dissent. I was wrong. Ruse is singing the same old tune. The chorus goes like this, "Why can't we just get along?" The real message is, "Why don't you arrogant atheists just shut up and learn to think like an appeaser?"

The teaser on the Ruse article sets the tone for what's coming. He says,

We who think that biblical literalism has no place in science classrooms should be standing together and fighting ignorance and prejudice. Why then do those of us against creationism live in a house divided?

Well Michael, there are several reasons. One of them is that you are setting up the division yourself by trying to define the problem on behalf of everyone else.

I'm opposed to Biblical literalism, just like you. But I'm not necessarily opposed to keeping it out of the schools at all costs. That's just not a priority for many non-Americans. As a matter of fact, I'd like to bring it into the schools and get students to debate evolution and creationism in the classroom. So, right away you're starting with an assumption. You say I'm supposed to advocate fighting religion in American schools and defending the American Constitution. You also frame the debate in terms of fighting creationism while I prefer to think of the battle as a fight between rationalism and superstition. You've lost me before you even get to the opening paragraph.

(Later on we'll see that your version of "ignorance and prejudice" is differnt than mine so we can't even agree on that.)

Ruse then goes on to describe the problem as he sees it,

... at the moment, those of us against creationism live in a house divided. One group is made up of the ardent, complete atheists. They want no truck with the enemy, which they are inclined to define as any person of religious inclination—from literalist (like a Southern Baptist) to deist (like a Unitarian)—and they think that anyone who thinks otherwise is foolish.

Okay, let's stop here for a moment and ponder how Ruse is defining his opponents. I am one of those people and there's a lot of truth in what Ruse just wrote.

I do indeed think that religion is behind the anti-science movement. I think that religion is the problem, not creationism. Creationism is just one symptom of the anti-science, anti-intellectual, stance of the most fervent believers. Theistic evolution is another symptom of what I think is fuzzy religious thinking about science, albeit not as outrageous as believing in the literal truth of Genesis [Theistic Evolution: The Fallacy of the Middle Ground].

It's easy to see the silliness of the Young Earth Creationists; however, I find it difficult to see the difference between the Intelligent Design Creationism of a Michael Behe or a Michael Denton and that of Ken Miller, Francis Collins, or Simon Conway-Morris. They look very simlilar to me.

Michael Ruse doesn't have this problem,

The second group is made up of two subgroups. One has as members liberal Christians who think that evolution is God's way of creating .... The second subgroup contains those who have no religious beliefs but who think that one should collaborate with the liberal Christians against a shared enemy, and who are inclined to think that science and religion are compatible.

There's the rub. The appeasers are atheists who think that Theistic Evolution is compatible with science.

Ruse makes it clear that he disagrees with "ardent atheists." To his credit, he raises then dismisses the argument that "ardent atheists" should keep quiet because they provide aid and comfort to the enemy. Instead, he raises anther point. Ruse criticizes the atheists like Dawkins because of their lack of scholarship.

If I thought Dawkins and company were right, I would defend them one hundred percent and let the chips fall where they may. My real problem is one of scholarship, put simply, which is I guess what you would expect of a university professor like myself. I would be a lot more impressed with the ardent atheists if I felt that they were making a genuine effort to engage in dialog with those whom they criticize. I do not mean actual physical dialog, but at the least intense study of the claims of those against whom they fulminate. Take, for example, Richard Dawkins's The God Delusion, and his critiques of the various arguments for the existence of God. Why does he not acknowledge that few if any Christians have ever claimed that the proofs are the true reason for the belief in God?

Booooooring. We've heard this whining before. Why doesn't Ruse acknowledge that people like me and PZ have carefully read Finding Darwin's God, Life's Solution, and The Language of God? We've examined the arguments made by the Theistic Evolutionists and found them wanting. What more can we do? I'm not a mind reader. I can't guess what sort of secret "sophisticated" arguments they might have lying in reserve. They haven't told us.

Ken Miller, Francis Collins, and Simon Conway-Morris are among the leading proponents of Theistic Evolution. They're the people Ruse wants to ally with. They've told us exactly why they believe in God and why they think science is compatible with their religion. I'm not buying it. I seriously wonder whether Ruse does either but I guess we'll never know since, as his allies, they are immune to the kind of criticism leveled at Dawkins.

Have you ever thought about why you'll never hear Ruse criticizing Miller and Collins for their lack of scholarship? Can you say "hypocrite"?

Maybe PZ, Dawkins and I are wrong. Maybe there really are rational arguments that reconcile Christianity (and other religions) with science. Maybe the conflict that everyone talks about is imaginary and people like Francis Collins have already found the solution. Maybe, but I doubt it. That's not the point. If Ruse truly believes we are wrong then let him engage in debate instead of just falsely accusing us of sloppy scholarship.

Having ordained that the "ardent atheists" are not scholars, he summarizes his opinion of us like this.

I start to suspect that these people ... in their way are tarred with the same features of which they accuse the creationists. There is a dogmatism, a refusal to listen to others, a contempt for nonbelievers, a feeling that they alone have the truth, that is the mark of so many of the cults and sects that have sprung on American soil since the nation's founding.

Hmmm ... so we're no different than religious cults, eh? What's the solution?

Please God-or non-God—let us quit fighting among ourselves and get on with the real job that faces us.

Wow! For an appeaser you sure have a funny notion of how to stop fighting among ourselves. First you insult and demean us then you say we should get along. That's ridiculous.

When I disagree with someone I don't pull any punches. In that sense I'm no different that Michael Ruse. However, I don't then turn around and ask my opponent to give up the beliefs I've just trashed and join me in fighting another battle—especially one that they're not interested in. That would suggest I wasn't listening to a word they said. But that's exactly what Michael Ruse is doing.

We need to accept the fact that atheists disagree on the mild form of creationism called Theistic Evolution. Some of us oppose it on the grounds that the logic behind it is no different than the logic of Intelligent Design Creationism. Other atheists don't see a problem with Theistic Evolution because, according to them, science and religion are compatible. Fine. We can agree to disagree and have lots of fun debating it at the same time.

But please don't try to shut me up by calling for a big tent strategy against the more extreme creationists. That's the whole point of the Ruse article in spite of the brief disclaimer in the middle. From the opening teaser to the very last sentence, the take-home message is for all atheists to come together. But it's a very special kind of coming together, isn't it? Our side has to give up everything. That sort of coming together usually goes another name. It's called surrender.

So here's my message to the appeaser athiests. If you don't like what we say then by all means speak out. Challenge us. Debate us. Show us why you think Theistic Evolution is very different from Intelligent Design Creationism. Write an article comparing Nature's Destiny by Michael Denton and Life's Solution by Simon Conway-Morris. Tell us why you choose to ally with Conway-Morris but oppose an intelligent design creationist like Denton. Make your case with scholarship. But please, please, stop whining about the fact we disagree. That's not going to change anything.

(Are you listening Chris Mooney and Matt Nisbet? This applies to you as well. If you support Theistic Evolution then tell us why. Don't try and confuse the issue with talk of "framing." We all know about frames. It's just a fancy word for spin.)

Monday's Molecule #22

 
Name this molecule. This is very easy for any student who's ever taken a biochemistry course. The goal here is to show everyone else just how important this molecule is for understanding basic biochemistry.

As usual, there's a connection between Monday's molecule and this Wednesday's Nobel Laureate. This one's hard because the connection isn't obvious. (Hint: It's related to last week's molecule and Nobel Laureate.) The prize (free lunch) goes to the person who correctly identifies both the molecule and the Nobel Laureate. (Previous free lunch winners are ineligible for one month from the time they first won.)

Comments will be blocked for 24 hours. Comments are now open.

Play the DNA Double Helix Game

 


Warning! This is a lot harder than it looks! [Double Helix Game].