Nobel Laureates: George Beadle and Edward Tatum

 

The Nobel Prize in Physiology or Medicine 1958.

"for their discovery that genes act by regulating definite chemical events"

George Wells Beadle (1903 - 1989) and Edward Lawrie Tatum (1909 - 1975) received the Nobel Prize in Physiology or Medicine for their work on the relationship between genes and enzymes—the "one-gene-one-enzyme" concept. They showed that single mutations usually affected production of a single enzyme in a pathway. This lead to the idea that genes encode proteins (enzymes). The concept of one-gene-one-enzyme was not meant to exclude the possibility that genes could encode RNAs or something else, in spite of the fact that this interpretation has become widely believed. The point of Beadle and Tatum's work was to show that there was a one-to-one correspondence between a gene and a protein.

THEME:Nobel LaureatesJoshua Lederberg, a former student of Beadle and Tatum's, shared the Nobel Prize with them in 1958.

The presentation speech was given by Professor T. Caspersson, member of the Staff of Professors of the Royal Caroline Institute.

Your Majesties, Your Royal Highnesses, Ladies and Gentlemen.

One of the most striking features in the development of science during the past two decades is the rapid advance in the diverse fields of biology. Here the tempo of progress continues to quicken. The research contains a vast and complex material whose major portion remains the business of specialists. The observations they make in the laboratories of basic research are apparently distant from the needs of the everyday world. But again and again we discover how short the step is from these basic findings to advances in medical therapy or diagnosis that are of importance to all of us in our daily lives.

For an example we need turn only to the previous Nobel Prize in Genetics, awarded to H.J. Muller for his discovery that X-ray irradiation can change the genetic material in living organisms. The discovery was made, and the detailed analysis carried out, in a type of small fruit fly, and at the time that the prize was awarded, perhaps gave the impression that its greatest interest was in its contribution to basic principles. Now, with the era of atomic energy upon us, we all know that the genetic risks from the high-energy radiation threatening man, belong to the things I just mentioned, of vital and immediate importance to us all.

Experimental genetics is a branch of modern biology in which progress has been especially rapid. The methods and points of view of this and its allied disciplines are indispensable for many fields of medicine today. This rapidly increasing importance of experimental genetics and cell research is easily understood. The research is now reaching towards the very elements of heredity, the structures within each cell that control its life and its behavior, and thus ultimately determine the development of the whole organism. Now we begin to see what the fundamental biological processes may be. That discoveries in this field have consequences in many others is surely no surprise to any of us.

The work of all three winners of the prize lies on this plane. Their studies are concerned with the very basis of heredity and the manner in which the genes function. That hereditary characters are transmitted from parents to offspring via special elements in the ovum and spermatozoon, the so-called genes, has long been known. The organism that develops from the fertilized ovum receives certain of the parents' characters through these genes, and the genetic material in the fertilized egg, that is to say, all these genes combined, determines the development of the organism.

The cells that together constitute an organism as a rule contain a complete set of genes characteristic of the species. In ordinary cell division these are divided and subsequently distributed equally between the two daughter cells. At fertilization, the different genetic materials from two individuals unite in the fusion of the egg and the sperm. The result of the sexual reproduction is to provide offspring with genes from both of their parents. In this way, individuals with differing combinations of characters originate. And just herein lies the biologic value of the sexual process, which can be traced throughout practically the entire animal and plant kingdoms. Without the renewal such a constant recombination of characters involves, an animal or plant species would not be able to survive the struggle for existence.

The characters, which are transmitted by the genes from generation to generation, present a picture of bewildering multiplicity. This very multiplicity of the genes' effects made it difficult to attack experimentally the problem of their structure and manner of functioning; it was impossible to trace straightforward lines that could serve as a background for an experimental study.

The situation was radically changed by Beadle and Tatum, who, through a daring and astute selection of experimental material, created a possibility for a chemical attack upon the field. Circumstantial evidence pointed to a similarity of the genetic mechanisms throughout the entire plant and animal kingdoms. Beadle and Tatum selected as object for their investigations an organism with very simple structure, a bread mold, Neurospora crassa, which is far easier to work with, in many respects, than the objects usually studied in genetics. It is able to synthesize its body substances from a very simple culture medium: sugar, salts, and a growth factor. When cultures of the mold are exposed to X-ray irradiation, mutations - that is, changes in individual genes - result as they do in other organisms. By producing a large number of such mutations and by means of an analysis of the material, which should serve as a model for analytic research, Beadle and Tatum succeeded in demonstrating that the body substances are synthesized in the individual cell step by step in long chains of chemical reactions, and that genes control these processes by individually regulating definite steps in the synthesis chain. This regulation takes place through formation by the gene of special enzymes. If a gene is damaged, for example through irradiation-induced mutation, the chain is broken, the cell becomes defective - and may possibly be unable to survive. Even in the formation of comparatively simple substances the steps in the synthetic chain are many, and consequently the number of collaborating genes large. This explains simply why gene function appeared to be so impossibly complex. The discovery provides our best means of penetrating into the manner in which the genes work and has now become one of the foundations of modern genetics. Its importance extends over other fields as well, however.

Especially valuable is the possibility it affords for detailed study of the processes of chemical synthesis in the living organism. In Neurospora material it is easy by means of X-ray irradiation to produce quickly a large number of strains in which the function of different individual genes has been disturbed. By comparing these strains we are able to determine in detail how the different stages of synthesis succeed one another when the cell's substances are formed. Beadle and Tatum's technique has become one of our most important tools for the study of cell metabolism and has already yielded results of significance to various problems in the fields of medicine and general biology.

The successful results with Neurospora also provided an incentive to continued efforts to probe the basic processes further with the aid of even simpler organisms. The bacteria are even more primitive than Neurospora. The bacterial genetic mechanism was little known; many even doubted that they had one comparable with that of the higher forms of life. Tatum extended the approaches worked out in Neurospora to the bacteria. When Lederberg came to Tatum's laboratory as a young student, they discovered that different bacterial strains could be crossed to produce an offspring containing a new combination of genetic factors. This is the counterpart of the normal sexual fertilization in higher organism; it is usually considered preferable here, however, to speak of «genetic recombination». Bacterial genetics has been developed, primarily through the efforts of Lederberg and his coworkers, into an extensive research field in recent years. He also contributed further evidence that the genetic mechanism of the bacteria corresponds to that of the higher organisms. Moreover, thanks to their simple structure and extraordinarily rapid growth, bacteria provided new and excellent possibilities for a more profound study of the genetic mechanisms. Lederberg has made many contributions in this field. Particularly important is his discovery that sexual fertilization is not the only process leading to recombination of characters in bacteria. Bits of genetic material can, if they are introduced into the bacterial body, become part of the genetic material of the bacterial cell and thus change its constitution. This is usually termed «transduction», and it is the first example demonstrating that it is possible experimentally to manipulate an organism's genetic material and to introduce new genes into it and, the organism new characters. Studies in this are now being carried out in many laboratories in different parts of the world.

The transduction process and certain other related phenomena have greatly improved our means of penetrating experimentally into the basic processes of cell function and cell growth. In all probability they will also prove to have great significance in the study of the function of the higher organisms under normal and pathologic conditions. Work in this field, carried out in laboratories throughout the world, has already greatly expanded our knowledge of the basic processes in bacteriophage infection and of the mechanism of virus infection. The observations also have opened the way to a more profound understanding of certain growth problems. Certainly cancer research will be increasingly influenced by the evolution of our knowledge of the organization of the genetic material and its manner of functioning, that has been made possible by the discoveries of this year's three winners of the Nobel Prize in Physiology or Medicine.

Doctor Beadle and Doctor Tatum. In consequence of an exemplary collaboration in which each has complemented the other to unusual advantage, it has been given to you to make discoveries of fundamental importance to our understanding of the mechanism of Life's processes.

Doctor Lederberg. At first in collaboration with your co-winners of this year's Nobel Prize, and subsequently, along ever-broadening independent lines, you have made possible the advance of research to the structure of the actual genetic material.

Gentlemen. In recognition of your outstanding contributions to science the Karolinska Institute has awarded you this year's Nobel Prize in Physiology or Medicine. On behalf of the Institute I wish to extend the warmest congratulations from your colleagues on your brilliant achievements.

It is my honoured privilege now to invite you to receive your awards from the hands of His Majesty the King.

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Who's Afraid of Bisphenol A?

 
The latest issue of the Tangled Bank points to an article on Giovanna Di Sauro about the dangers of bisphenol A. Recall that bisphenol A is a chemical found in polycarbonate drinking bottles [see Is Your Water Bottle Killing You?].

The first article outlines the chemistry of bisphenol A and its effect on mammalina cells. It refers to the latest papers that have prompted a ban on bisphenol A [Who's Afraid of Bisphenol A: (Part 1)].

The second article discusses whether bisphenol A is dangerous to humans. Can it cause cancer? [Who's Afraid of Bisphenol A: (Part 1)].

I won't tell you the conclusion because, if I did, you wouldn't read the excellent articles on Giovanna Di Sauro. But here's a teaser ...

Making decision in relation to BPA is made even more complicated by the fact that there are many estrogen-like compounds in our environment which are already in the food chain, and which we can absorb by consuming both animal and vegetable products: BPA absorption might only be the tip of the iceberg when it comes to xenoestrogen intake. It would be useful to see what the "total xenoestrogen insult" is in an average adult who consumes meat, vegetables and dairy, and to see what role BPA is playing to increase this insult. Only then we will be able to assess whether cancer risk arising from BPA ingestion is significant, or whether we would do better to worry about different sources of xenoestrogen.

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Tangled Bank #105

 
The latest issue of Tangled Bank is #105. It's hosted at The Beagle Project Blog [Tangled Bank #105].

Welcome, readers, to this tag-teamed edition of the Tangled Bank blog carnival.

In the left-justified corner, all the way from the north Yorkshire coast, not far from where Darwin 'took the waters' in Ilkley, it's Peter McGrath.

And in the right-justified corner, coming to you from London, just a few miles away from Downe Bank, Darwin's inspiration for the tangled bank where "endless forms most beautiful and most wonderful have been, and are being, evolved", it's Karen James.

Well, you glorious swine. Speaking for myself, my blogreading life was full enough without discovering some of the new delights carnivalled here. The long evening reading all these posts has been a 'mental riot' (Darwin's description of the intellectual ferment when he was incubating The Origin), for which many thanks and the RSS has a slew of new entries. A tangled bank is not a monoculture, and I think we can offer something for all here.

I would never call our dear readers much less our prolific bank-tanglers 'swine', however glorious, but I certainly do share Peter's admiration for this fortnight's entries.

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If you want to submit an article to Tangled Bank send an email message to host@tangledbank.net. Be sure to include the words "Tangled Bank" in the subject line. Remember that this carnival only accepts one submission per week from each blogger. For some of you that's going to be a serious problem. You have to pick your best article on biology.

I Don't Care

 
There's been a lot of talk in the past two days about the true beliefs of Albert Einstein. A new letter has come to light suggesting that he was a pantheist at best. Richard Dawkins discusses it at Richard Dawkins discusses Einstein's new letters.

Albert Einstein died in 1955. I don't care whether he believed in a personal God, or a Spinoza God, or no God at all. What he believed has no bearing on whether supernatural beings exist or not. The beliefs of Francis Collins and Ken Miller are equally irrelevant.

What counts is the arguments they advance to bolster their beliefs and in the case of Albert Einstein we don't have a very good record of what those arguments are. This isn't true of some other scientists (Collins, Miller) where we can examine the claims to see if they are rational.

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Bertrand Russell's Teapot

 
Here's the original version of Bertrand Russell's argument, quoted from Russell's teapot on Wikipedia.

If I were to suggest that between the Earth and Mars there is a china teapot revolving about the sun in an elliptical orbit, nobody would be able to disprove my assertion provided I were careful to add that the teapot is too small to be revealed even by our most powerful telescopes. But if I were to go on to say that, since my assertion cannot be disproved, it is an intolerable presumption on the part of human reason to doubt it, I should rightly be thought to be talking nonsense. If, however, the existence of such a teapot were affirmed in ancient books, taught as the sacred truth every Sunday, and instilled into the minds of children at school, hesitation to believe in its existence would become a mark of eccentricity and entitle the doubter to the attentions of the psychiatrist in an enlightened age or of the Inquisitor in an earlier time.

This is a very powerful argument; however, it relies on one important bit of information, namely that we could not detect Russell's teapot if it really were orbiting the sun.

This important assumption is about to be put to the test now that the teapot has been located and we have the Hubble telescope in orbit. See The Wedgewood Document on Sneer Review for all the details about the experiment.

We atheists could be in big trouble if this pans out ....

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[See A Teapot in Space for the connection between Russell's teapot and The Hitchhiker's Guide to the Galaxy.]

Monday's Molecule #71

 
Today is Tuesday so it must be time for Monday's Molecule. (Oops! I was traveling yesterday and didn't get around to posting. It doesn't matter since today is a much more important day anyway—it's my birthday.)

Today's molecule is essential for all life as we know it. You need to identify the molecule and give its correct common name as well as the formal IUPAC name. Pay attention to the correct common name—some trivial names just won't do.

There's an indirect connection between today's molecule and a Nobel Prize. The prize I have in mind was not awarded for working out the structure of the molecule. We've already covered that prize. Instead, the prize was for learning something very important about the pathway for synthesis of the molecule. Something genetic.

The first person to correctly identify the molecule and name the Nobel Laureate(s) wins a free lunch at the Faculty Club. Previous winners are ineligible for one month from the time they first collected the prize. There are three ineligible candidates for this week's reward.

THEME:

Nobel Laureates
Send your guess to Sandwalk (sandwalk (at) bioinfo.med.utoronto.ca) and I'll pick the first email message that correctly identifies the molecule and names the Nobel Laureates. Note that I'm not going to repeat Nobel Laureate(s) so you might want to check the list of previous Sandwalk postings.

Correct responses will be posted tomorrow. I may select multiple winners if several people get it right.

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

UPDATE: The molecule is pyridoxine (3- hydroxy-4,5 -bis (hydroxymethyl) -2-methylpyridine) also known as vitamin B₆. (Pyridoxal and pyridoxamine, along with pyridoxine, make up the members of the B₆ family.)

The Nobel Laureates are George Beadle and Edward Tatum who discovered that mutations in Neurospora affected single enzymes in a pathway. Mutants that were unable to grow on vitamin B₆ were among the first mutants they isolated in the 1940's.

The winner this week is Bill Chaney from the University of Nebraska.

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White Water

 
These photos were taken near the Champlain Bridge on the Ottawa river not far from where I grew up. This is right in the heart of Ottawa (Canada).

We never saw anything like this when we were children. The most exciting thing on the Champlain rapids was the occasional log and, rarely, a canoe shooting the rapids.

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The Dandelion Festival in Ottawa

 
Every year in May there's a famous dandelion festival in Ottawa (Canada). People come from all over the world to see the millions of dandelions along the parkways and walkways throughout the city.


Dandelion lovers are very tolerant and generous with their praise of lesser flowers. Here's a small group of dandelion fans admiring some other kind of yellow flower.


The various governments in Ottawa take advantage of the dandelion festival to promote other festivals that are scheduled in early May. The tulip festival is a prime example. Being ecumenical chaps, the tourists who come to see the dandelions will naturally drop by to look at the tulip beds, if they have time. Tulips are pretty picky about where they grow so the flowers are clustered in only a few spots in the city. (Dandelions are everywhere.)

Today was a very nice day in Ottawa. Here's a group of flower lovers who are taking a brief look at the tulips around Dow's Lake. There were about 20,000 people there when we drove by on our way back from seeing the dandelions.



Some tulips are almost as pretty as dandelions ....


I said almost.

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The Best Flowering Plant

 
Tulips are the best flower according to Jane and Michael on Beer with Chocolate. Jane and Michael may have been slightly influenced by their Birthday Adventure in Holland.

Much as I hate to disagree with my offspring (), tulips are not the best flowering plant. Dandelions (from the French dent de lion - lion's teeth) are the best plant.

Not only are dandelions beautiful, they are hardy and ubiquitous. They can grow almost anywhere with a minimum of care. In fact, you have to make special efforts to get rid of them—something you would only do if you have an extreme anti-dandelion prejudice. These days, civic governments throughout Canada are banning herbicides in order to save the dandelion. (You don't see anyone doing that for tulips, do you Jane?)

The most common species of dandelion is Taraxacum officinale.

The flowers are pretty. You can eat the leaves. The leaves will cure many diseases. You can make wine with dandelions. A company in Belgium called Brasserie Fantôme even makes a dandelion beer called Fantôme Pissenlit. (= wet the bed, from dendelion's medicinal properties).

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DNA Replication in E. coli: The Solution

In an earlier posting I described a problem that we often use to encourage critical thinking in our undergraduates. The problem is how can E. coli divide faster that the time it takes to replicate it's chromosome? [DNA Replication in E. coli: The Problem]

Recall that DNA replication always begins at an origin of replication. In bacteria there is usually one origin per chromosome or plasmid. (Eukaryotic chromsomes have multiple origins.)

The replisomes assemble at the origin and then move in opposite directions around the chromomome until the meet at the termination region. Each replisome moves at a rate of 1000 nucleotides per second and it takes about 38 minutes to complete one round of replication. But E. coli can divide every 20 minutes. That's the problem.

The firing of an origin is controlled by regulatory proteins. These proteins trigger the assembly of replisomes at the origin sequences. When most of us are first presented with this problem we think in terms of the events occurring sequentially. Thus, a chromosome is copied, the daughter chromosomes segregate, and a new round of replication begins.

This isn't what happens when the cells are dividing rapidly. Instead, a new round of replication begins at the "future origin" before the current round of replication is completed. At any given instant, there can be six or eight replication forks synthesizing DNA simultaneously inside the cell.

In order for the cell to divide every 20 minutes, all that is required is that a round of replication terminate every 20 minutes. This means that origins fire every 20 minutes. When the daughter chromosome segregate into daughter cells, they are already partially replicated in preparation for the next cell division.

Here's how Fossum et al. (2007) describe the solution in a recent paper in EMBO Journal.

The bacterium Escherichia coli has a single chromosome that is replicated from a single origin (oriC), bidirectionally to the terminus, once per division cycle (Kornberg and Baker, 1992). The cell cycle of slowly growing bacteria is quite similar to that of eukaryotic cells (Boye et al, 1996), with the G1, S and G2/M phases of bacteria termed B, C and D, respectively. E. coli (and certain other bacteria) is capable of very rapid growth in rich medium, with doubling times as short as 20 min. The replication time, however, remains long, with approximately 60–90 min required to replicate and segregate the chromosome. Therefore, the cell cycle is more complicated during rapid growth (Figure 1). If the time it takes to synthesize and segregate the daughter chromosomes (C+D) exceeds one generation time, a new round of replication must be initiated before the previous round is completed (Cooper and Helmstetter, 1968). Thus, initiation occurs at two origins in the 'mother' cell. It can even occur in the 'grandmother' cell at four origins if the time it takes to replicate and segregate the chromosome exceeds two generations. These initiations at two or four origins occur simultaneously, as one event per division cycle (Skarstad et al, 1986). While E. coli and Bacillus subtilis are two examples of bacteria capable of performing multifork replication, other bacteria, such as Caulobacter crescentus, are not. Eukaryotic cells do not replicate with overlapping cycles, but do initiate DNA replication at multiple replication origins, and thus perform a different kind of multifork replication, with the multiple forks on the same copy of the genome (Diffley, 2004).

Figure 1:Replication pattern of rapidly growing E. coli wild-type cells. Cells (yellow) with chromosomes (blue lines) and origins (black squares) are drawn schematically to show the number of replication forks and origins at different stages of the cell cycle. In this example, initiation of replication occurs at four origins at the same time as cell division (bottom). A young cell therefore contains four origins and six replication forks (upper left). As replication proceeds, the oldest pair of forks reach the terminus and the two sister chromosomes segregate. The cell then contains four origins and four replication forks (upper right). Initiation then occurs again at 4 origins and generates 8 new forks giving a total of 12 forks, as cell division approaches (bottom). Because there will be cell-to-cell variability, some cells will contain eight origins before they divide, whereas cells that divide before initiation of replication will contain only two origins (not shown). However, the majority of the cells in the culture will contain four origins.

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Fossum, S., Crooke, E. and Skarstad, K. (2007) Organization of sister origins and replisomes during multifork DNA replication in Escherichia coli. EMBO J 26:4514–4522 [doi:10.1038/sj.emboj.7601871]

Gene Genie #31

 
The 31st edition of Gene Genie has been posted at Adaptive Complexity [Capitalists, Genetic Tests and Your DNA].

Everyone knows there is a lot of crazy stuff on the internet, but did you know there is a lot of great writing about genes, genetics, and human diseases? And believe it or not, sometimes these pieces are written by people who know what they're talking about. If you're looking for what's new in human genetics, you've come to the right place.

Welcome to the 31st Gene Genie, a blog carnival dedicated to great blogging about human genes and how they impact our health. This Mother's Day edition includes an in-depth highlight of the growing industry of personalized genetics.

The beautiful logo was created by Ricardo at My Biotech Life.

The purpose of this carnival is to highlight the genetics of one particular species, Homo sapiens.

Here are all the previous editions .....

1. Scienceroll
2. Sciencesque
3. Genetics and Health
4. Sandwalk
5. Neurophilosophy
6. Scienceroll
7. Gene Sherpa
8. Eye on DNA
9. DNA Direct Talk
10. Genomicron
11. Med Journal Watch
12. My Biotech Life
13. The Genetic Genealogist
14. MicrobiologyBytes
15. Cancer Genetics
16. Neurophilosophy
17. The Gene Sherpa
18. Eye on DNA
19. Scienceroll
20. Bitesize Bio
21. BabyLab
22. Sandwalk
23. Scienceroll
24. biomarker-driven mental health 2.0
25. The Gene Sherpa
26. Sciencebase
27. DNA Direct Talk
28. Greg Laden’s Blog
29. My Biotech Life
30. Gene Expression
31. Adaptive Complexity

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On the Evolution of the Blood Clotting Pathway

Theme

Blood Clotting
Last year I spent some time studying blood clotting. You can read the series of postings by clicking on the "Theme" link.

One of the reasons for reading up on this topic was because the creationists were promoting it as another example of something that could not evolve. Micheal Behe was one of those creationists.

The data is now in. Russel Doolittle has been working on the evolution of the clotting cascade and the latest results incorporate the information from the lamprey genome. Suffice to say, Behe's claims have been decisively refuted.

Ian Musgrave has the scoop in an excellent article on Panda's Thumb [Behe vs Lampreys: A modest proposal]. This should put an end to ignorant speculation about the non-evolvability of the blood clotting pathway. Or, to be more precise, it should put an end to such speculation by any intelligent, rational, person.

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Blogger’s Code of Conduct

 
If you're not going to follow the Blogger's Code of Conduct, this is what you're supposed to put on your blog.

This is an open, uncensored forum. We are not responsible for the comments of any poster, and when discussions get heated, crude language, insults and other "off color" comments may be encountered. Participate in this site at your own risk.

Don't say you haven't been warned.

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Something to look forward to ....

 

ATHEISTS and agnostics are decent people whose tormented souls will burn for all eternity in the scorching fires of hell, Britain's biggest catholic said last night.

Cardinal Cormac Murphy O'Connor said non-believers should be respected, right up to the point of death when they will finally come face to face with Satan and his blood-soaked pitchfork.

He told a conference in London: "Those without faith should not be shunned or abused. Jesus and Beelzebub are already cooking something up for them, don't you worry about that."

Gee, I wonder how he feels about Jews and Muslims?

The one good thing about all of this is that my agnostic friends will be there to keep me company. It will serve them right for not making up their minds about Beelzebub.

(Christianity is supposed to be one of the monotheistic religions. Could someone who is an expert please explain Beelzebub? Is he/she a god or just some minor supernatural being like Gabriel?)

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[Hat Tip: RichardDawkins.net]

Reciting the Lord's Prayer in Ontario's Legislature

 
Premier Dalton McGuinty started the debate in February when he called for a study of the current practice [Lord's Prayer review ordered].

Queen's Park Bureau Chief
In a bid to separate church and state – or, in this case, province – Premier Dalton McGuinty wants to end the practice of reciting the Lord's Prayer in the Ontario Legislature.

McGuinty surprised observers at Queen's Park this morning by appealing for an all-party committee to replace the prayer.

"I believe it is time for Ontario's Legislature to better reflect Ontario's reality and celebrate our diversity," the premier wrote to the leaders of the Progressive Conservatives and New Democrats.

"It is time to move beyond the daily recitation of the Lord's Prayer in the Ontario Legislature to a more inclusive approach that reflects 21st century Ontario," he said, noting the prayer was last updated in 1969.

"Our counterparts in other provinces and the federal government have adjusted their customs to reflect the diversity of the population.

"The members of the Ontario Legislature reflect the diversity of Ontario – be it Christian, Jewish, Hindu, Muslim, Sikh or agnostic. It is time for our practices to do the same. That is the Ontario way," McGuinty wrote.

This sounds pretty enlightened. Later on we learned that McGuinty had in mind multiple prayers and not just abolishing the practice altogether.

The committee has been struck. One of the first things they did was to set up a website. Within days the website crashed from the volume of submissions [Proposal to scrap Lord's Prayer crashes gov't website]. Can you guess who was responding? Yes, that's right, thousands of people who want to keep the Lord's Prayer in the legislature. It doesn't matter to them if we have Jewish, Muslim, Hindu, Buddhist, and atheist MPP's. No sireee. They all have to say the Lord's Prayer before doing any business in the house. That's only fair.

Naturally, it's the Conservatives who are leading the charge to stifle tolerance and promote bigotry. The latest example is a column from one of the editors of The National Post [John Turley-Ewart: Ontario shouldn't ditch the Lord's Prayer]. You won't believe the silliness of his argument ...

Christians across the province see the Premier's move as a sop to those who think saying the prayer is inconsistent with multiculturalism. Those who disapprove of such a move include Premier McGuinty's own mother. But that has not caused the Premier to waver in his position for change. He is on record saying: "We've got a responsibility to ensure that all people feel truly at home here."

But the move has left many Christians in Ontario wondering if the province is still their home; if it is a place that is in tune with the Christian principles that have informed the province's political and economic values — values that underpin Ontario's success story as a democratic, prosperous province. The Lord's Prayer, recited by Catholics and Protestants alike, is more than words that pay homage to God.

It represents a piece of common ground that Catholics and Protestants could agree on -- a daily ritual that helped in whatever small way to break down the intolerance that existed between the majority Protestants and minority Catholics who founded the province.

In its own small but important way, the recital of the Lord's Prayer is a symbol of the tolerance that has made Ontario the great place it is today to live. That Premier McGuinty would consider dropping the prayer in the name of tolerance is, thus, ironic. It would do a disservice to the province's history and its Christian heritage.

Ontario should keep the Lord's Prayer, add other prayers from different faiths if thought appropriate, and avoid the folly of dismissing history for feel good, fuzzy visions of multiculturalism.

Hmmm ... let's see if I understand this correctly. Forcing atheists to recite, or listen to, the Christian prayer every day, is a symbol of "tolerance."

Earth to John Turley-Ewart ... you are promoting bigotry and intolerance. If you want your Christian friends to say the Lord's Prayer then let them say it by themselves in the privacy of their offices before going to the House to do Ontario's business.

Just because a majority of MPP's may be Christians is no reason for the majority to force their religion on everyone else. That's not the Canadian way.

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Amino Acids and the Racemization "Problem"

Amino acids come in two different "flavors" depending on the orientation of atoms bound to the central α-carbon. The two possibilities are L- and D- configurations. In the examples shown here, you can see that the two forms of serine, L-serine and D-serine, are mirror images of each other. These forms are called stereoisomers because they contain the same atoms with different mirror image arrangements.

Stereoisomers cannot be interconverted without breaking covalent bonds. They are distinct molecules. Almost all amino acids in living organisms are L-amino acids. Proteins are almost exclusively composed of L-amino acids and not D-amino acids.

The α-carbon atom of amino acids is chiral, or asymmetric. You need at least one chiral atom in a molecule in order to have stereoisomers. One amino acid (glycine) does not have a chiral α-carbon so there is only one configuration of glycine.

When amino acids are synthesized in a chemistry laboratory, you often end up with a mixture of equal amounts of L- and D- stereoisomers. When you examine the amino acids found in meteorites and in the vicinity of stars, you find a mixture of both stereoisomers. These are called racemic mixtures since the process of converting one stereoisomer into another is called racemization.

Now, the fact that amino acids in living organisms are all L- forms is not a problem since the L-amino acids are the only ones that are synthesized in any appreciable amounts. All of the amino acid biosynthesis pathways produce only L- forms and not D- forms. This is not unusual since enzyme catalyzed reactions are usually sterospecific. It's not a surprise that modern proteins are composed of L-amino acids because those are the only ones available inside the cell.

The "problem" arises when we start to think about how life arose in the first place. The general assumption is that life arose in a warm pond containing a racemic mixture of L- and D- amino acids. If that is true then how did life evolve to select exclusively L-amino acids? Most of the proposed solutions to these questions make assumptions about how the primordial soup could have spontaneously come to have a preference for L-amino acids over D- amino acids.

I'd like to propose another way of thinking about this problem.¹

Let's assume there was a primordial soup where amino acids came together spontaneously to form short peptides. In the beginning, the soup contained racemic mixtures of the D- and L-forms of amino acids. These molecules were formed spontaneously by the kinds of chemical reactions that are simulated in the laboratory.

Some of the random peptides acted as catalysts for chemical reactions. This is observed in modern-day experiments. One kind of reaction, amino acid synthesis, would have been especially favorable since it created more amino acids and led to more peptides.

The simplest pathway to more amino acids is the formation of glycine, probably by adding an amino group to acetate or glycerol. (This pathway no longer exists.) The next simplest is the conversion of pyruvate (a common three carbon organic acid) to alanine—a fairly simple transamination reaction.

In modern cells, this reaction is catalyzed by sophisticated transaminases but in the beginning it would have been catalyzed by short peptides that formed spontaneously in the primordial soup. Such reactions are stereospecific, the modern reaction only produces L-alanine and never D-alanine (well, hardly ever!). Let's assume that a similar reaction in the beginning produced, by chance, L-alanine.

Another simple pathway is from oxaloacetate (a common four carbon organic acid) to aspartate. Both of these reactions require a relatively simple addition of ammonia to a keto group and both reactions could have been catalyzed (inefficiently) by the same peptide.


As I mentioned above, enzyme catalyzed reactions tend to be stereospecific so it's likely that the early products were L-alanine and L-aspartate from the same enzyme. They could have been D-alanine and D-aspartate, but they weren't. As the concentrations of glycine, L-alanine and L-aspartate increased there were more and more peptides formed and the new peptides were enriched in these two particular L-amino acids.

Other simple amino acid synthesis reactions were catalyzed in the primordial soup. The most likely one is the synthesis of serine from glycerol or glycerate (common three carbon organic alcohols or organic acids). Again, the enzyme catalyzed reactions will only produce one isomer of the amino acid and there might have been selection for those parts of the soup that made L-serine (instead of D-serine) because the L-serine could more easily combine with L-alanine and L-aspartate to make many more peptides. In this case, the specificity of the reaction derives from selecting D-glycerate over L-glycerate as the substrate.

L-serine is the precursor to L-cysteine so it's likely that L-cysteine was also one of the early amino acids to accumulate in the primordial soup. This was an important addition to the repertoire since L-cysteine has a sulfur group and that leads to many more possibilities for catalytic active sites in the peptides. Note that once L-serine began to accumulate in the soup it led directly to the stereospecific L-cysteine. You can't make D-cysteine from L-serine so there's no racemization problem once L-serine accumulates.

L-glutarate (from alpha-ketoglutartic acid, a common five-carbon organic acid) is another good candidate for the primitive amino acids. (It's quite possible that L-alanine, L-asparate, and L-glutamate were all made by the same primitive enzyme using very similar 3, 4, and 5-carbon substrates.)


At this point there would have been all kinds of peptides containing various combinations of L-alanine, L-aspartate, L-serine, glycine, L-cysteine, and L-glutamate since these six amino acids have become much more abundant that the ones formed spontaneously by uncatalyzed reactions that produce a racemic mixture. This is probably the time when there was a shift to encoding peptides in a sequence of nucleotides.

This is an important point. The shift to more and more complex peptides did not have to take place in a random mixture of both forms of all 20 amino acids. It could have taken place under conditions where there was already a significant enrichment of a small number of L-amino acids due to catalytic biosynthesis from non-amino acid precursors.

There's some suggestive evidence to indicate that the primitive genetic code was much simpler than the one we see today and may have only had codons for the six initial amino acids. The other L-amino acid synthesis pathways arose later on and the genetic code expanded when codons were "stolen" from the precursors of these new L-amino acids.

One of the primitive codons for aspartate, for example, might have been AXX (any codon beginning with A). L-aspartate is the precursor to: L-lysine (AAA, AAG), L-asparagine (AAU, AAC), L-threonine (ACX), L-methionine (AUG), and L-isoleucine (AUU, AUC, AUA). The idea is that the new amino acids were originally synthesized on L-aspartate that was attached to its tRNA and they were incorporated into proteins at some positions in place of L-asparate. (This hypothesis on the origin of the genetic code was developed by my former colleague Jeff Wong. The idea came to him while teaching an undergraduate course in biochemistry ... but that's another story.)

Note that many amino acids are made from pre-existing amino acids. Once you have a supply of L-aspartate, for example, it follows that the derivatives will also be L- forms. There's no need to postulate that the preferential use of L-asparagine, L-threonine, L-methinione, and L-isoleucence, in contrast to the D- forms, arose independently. This greatly reduces the probability problem that most people are hung up on.

I don't have any good ideas about how the transition to encoded peptides happened but that's not the real point of this speculative posting.

The real points are ....

1. The most primitive catalysts were probably not very big. They were probably composed of mixtures of L- and D-amino acid residues.
2. The first important step was synthesis of new stereospecific amino acids which meant that the process was no longer dependent on the original pool of compounds that formed spontaneously.
3. The first peptides and polypeptides (proteins) probably contained only six amino acids. These are the amino acids that can be easily made from readily available precursors.

If you think about the origin of life in this way it will help you to understand why biochemists don't think the "racemization problem" is a real problem. This scheme will also help you to understand why some *particular* amino acids came to be enriched in proteins and not all of the other amino acids that were in the primordial soup in the very beginning. (There are far more than 20 amino acids.)

The original choice of the first L-amino acids over their D-isomers was probably an accident. It could just as easily have been the D- amino acids.

UPDATE: I now believe that Metabolism First and the Origin of Life is a more likely explanation for the origin of life. Please ignore references to "primordial soup" in the essay above. My conversion doesn't change the point. In the beginning very simple amino acids were spontaneously synthesized in restricted environments around thermal vents. By chance, the first chiral amino acid, alanine?, may have been L-alanine. All other may have been synthesized using L- amino acid precursors and this explains the the racemization problem.

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1. This is a modified version of an article that was originally posted on talk.origins in January, 2004.

DNA Replication in E. coli: The Problem

I've started reading microcosm by my favorite science writer, Carl Zimmer [Buy This Book!]. Watch for a review, coming soon.

I was mildly disappointed to see Carl repeat a common myth about DNA replication in E. coli on page 29. Since we often use this myth to teach critical thinking in our undergraduate classes, I thought it would be worthwhile to discuss it here.

Today I'm going to present the problem and let everyone think about a possible solution. On Sunday, I'll publish the answer. (If you know the solution, you are not allowed to post it in the comments—I'll delete those comments. You can ask for clarification or speculate.)

Here's what Carl says at the top of page 29.

E. coli faces a far bigger challenge to its order when it reproduces. To reproduce, it must create a copy of its DNA, pull those chromosomes to either end of its interior, and slice itself in half. Yet E. coli can do all of that with almost perfect accuracy in as little as twenty minutes.

Today, we're not concerned about the 20 minute generation time but I note, for the record, that the average generation time of E. coli, in vivo, is about one day. I also want to mention that the 20 minute generation time is an extreme example that's achieved only under the most extraordinary circumstances. Typical generation times in the lab are about 30 minutes.

However, that's not the problem. Let's assume a generation time of 20 minutes.

In the next paragraph Carl says ...

The first step in building a new E. coli—copying more than a million base pairs of DNA—begins when two dozen different kinds of enzymes swoop down on a single spot along E. coli's chromosome. Some of them pull the two strands of DNA apart while others grip the strands to prevent them from twisting away or collapsing back on each other. Two squadrons of enzymes begin marching down each strand, grabbing loose molecules to build it a partner. The squadrons can add a thousand new bases to a strand every second.

What Carl is referring to the the assembly of replication complexes (replisomes) at the origin of replication. Once those complexes are assembled, replication fires off and proceeds in opposite directions (bidirectionally) until the two fork meet at the opposite side of the chromosome.



Carl is correct when he says that the forks move at 1000 nucleotides per second. Later on in his book he mentions that the size of the E. coli chromosome is 4,600,000 base pairs or 4,600 kb (p. 116). At 1000 nucs per second it would take 4600 second to replicate this DNA if there was only one replication fork. Since there are two, it will take 2,300 seconds.

You can do the math. This is 38 minutes. It is a correct number—it takes at least 38 minutes to replicate the E. coli chromosome, not 20 minutes as stated earlier. It is true that the generation time of E. coli can be as short as 20 minutes under extraordinary circumstances.

Here's the problem. How can E. coli divide faster than it can replicate it's chromosome?

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Ben Stein's Dangerous Idea

 
Uncommon Descent is the Intelligent Design blog of Bill Dembski, Denyse O'Leary and their friends. It represent the best that the IDiots have to offer.

Yesterday's posting by DLH is an example of the best sort of creationist reasoning. The posting is an extensive quotation from an article by Robert Meyer originally posted in New Alliance Magazine [Ben Stein’s Dangerous Idea]. Here are the first three paragraphs quoted on the blog ...

Ben Stein has a dangerous idea. His idea is that professors and teachers who express skepticism about Darwinism are likely to find themselves not granted tenure, castigated and ridiculed, and disqualified from the opportunity to have research papers published.
. . .
Having reviewed the movie myself, it appeared that Stein was trying to make the case for academic freedom, not attempted to convert anyone to a particular ideological position.

Stein, in fact, never makes it known what particular beliefs he holds personally, he merely makes it known that he is disgusted by the idea that someone could lose their job over honest doubts about Darwinism.

No, your eyes are not deceiving you. Re-read that last paragraph. For all we know Stein may be a secret evolutionist. He's only interested in academic freedom. It's just a coincidence that the phrase "No Intelligence Allowed" uses the same word as Intelligent Design.

Jeesh. And you wonder why we call them IDiots?

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Make Englishe the Only Offal Language

 
I'm with Orac and Orcinus on this one. This is just too delicious to resist.¹

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1. Although, as a notoriously bad speller, I have made some pretty similar mistakes on Sandwalk.

Congratulations Jason Rosenhouse!!!

 
A big event just happened at Evolutionblog—Jason Rosenhouse got tenure [Tenure!]. Congratulations Jason.

I'll let him describe the process ....

I got tenure! Yay! By my count it's been about fifteen years getting to this point. I started studying mathematics seriously in my last two years of college (a rather late start in this profession). Then it was five years of graduate school, three years as a post-doc in Kansas, and now five years at JMU. Pretty satisfying. Suddenly that obnoxious and contentless rejection letter I received a month ago on a paper the journal should have been honored to publish doesn't seem to sting so much. (I'll just patch it up and send it off to the next journal, where it will languish for ten months to a year. What do I care? It's not like I'm in any great hurry to publish anymore!)

So there you go. Guess now I can tell you what I really think...

I guess this is when we discover that Jason is really a closet IDiot.

UPDATE: It didn't take long ...

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Nobel Laureates: Arvid Carlsson and Paul Greengard

 

The Nobel Prize in Physiology or Medicine 2000.

"for their discoveries concerning signal transduction in the nervous system"

Arvid Carlsson (1923 - ) and Paul Greengard (1953 - ) received the Nobel Prize in Physiology or Medicine for their work on identifying dopamine as a neurotransmitter. They also showed that L-dopa [Monday's Molecule #70], a precursor of dopamine, could relieve the symptoms of dopamine depletion and help control the symptoms of Parkinson's disease. They shared the prize that year with Eric R. Kandel.

THEME:Nobel LaureatesThe presentation speech was given by Professor Urban Ungerstedt of the Nobel Committee at Karolinska Institutet. (The date was, of course, December 10th as always. This is the anniversary of Alfred Nobel's death.)

Your Majesties, Your Royal Highnesses, Ladies and Gentlemen,

This year's Nobel Prize in Physiology or Medicine concerns the most complex structure in the universe that we know of - the human brain. It consists of 100 billion nerve cells, which is the same number of cells as the total number of human beings that have ever lived on this earth.

We talk about the "Internet revolution"; 35 million Internet users who communicate now and then - what is that compared to the nerve cells we all carry within ourselves! 100 billion nerve cells that communicate continuously.

It is this communication, "signal transduction in the nervous system," which is the subject of this year's Nobel Prize. A single nerve cell forms thousands of contact points, so-called synapses, with other nerve cells. In these synapses the nerve cells communicate by chemistry; one cell releases a transmitter, which reaches the other cell.

Professor Arvid Carlsson proved that dopamine is such a transmitter. The general belief was that dopamine was a precursor of other transmitters and of little functional importance. However, Professor Carlsson was able to show that dopamine existed in specific parts of the brain and concluded that it was a transmitter in its own right.

He then used a naturally occurring substance, reserpine, which empties the dopamine from the nerves, and found that the animals lost their ability to move. He realized that it must be possible to restore the dopamine levels with L-DOPA, a precursor of dopamine. In a conclusive, dramatic experiment he showed that the animals regained their ability to move when he gave them L-DOPA.

Reserpine had depleted dopamine and had given the animals the symptoms of Parkinson's disease, that is, rigidity and inability to move and react to stimuli in the environment. When the animals were given L-DOPA, dopamine was produced again in their brains. In this way the idea of treating Parkinson patients with L-DOPA was born. This enables millions of patients around the world to live a normal life.

Professor Paul Greengard showed what happens when dopamine and other similar transmitters stimulate a nerve cell. Receptors on the cell surface activate enzymes in the cell wall, which starts the production of second messengers. These messengers travel into the cell and activate a protein kinase, which starts to bind phosphate groups to other proteins, in this way altering their function. This leads, for example, to the opening of ion channels in the cell membrane and a change in the electrical activity of the cell.

Professor Greengard then showed that dopamine and other transmitters affect a central regulatory protein, which has been called DARPP-32. Like the conductor of an orchestra, it tells other proteins when and how to be activated.

This so-called "slow synaptic transmission" controls our movements and also those processes in the brain that elicit emotions or react to addictive drugs such as cocaine, amphetamine and heroin.

Professor Eric Kandel showed that transmitters of the same type as studied by Arvid Carlsson, via the protein kinases characterized by Paul Greengard, are involved in the most advanced functions of the nervous system such as the ability to form memories.

Imagine how difficult or impossible it must be to study how memory is formed in a human brain with 100 billion nerve cells. Eric Kandel, therefore, did something which is classical in all natural science: He chose to study a simpler model system, a sea slug, Aplysia, which has 20,000 nerve cells. He did it with the conviction that even primitive animals must learn in order to survive.

The sea slug has a withdrawal reflex protecting its gills. If they are touched repeatedly, they react less and less - just as human beings do when subjected to an unexpected touch. If, on the other hand, the touch is forceful the reflex is amplified and becomes stronger and stronger.

The habituation or amplification effect lasts only for a few minutes. One may say that the sea slug exhibits a short-term memory. If the forceful stimulus is repeated several times, the sensitization may remain for weeks, that is, the sea slug develops a long-term memory.

Professor Kandel was able to show that habituation to touching was due to changes in the synapse, the contact point between the nerve cells. During habituation less and less transmitter was released.

The forceful stimulus that formed the long-term memory worked in a completely different way. Second messengers activated protein kinases that entered the cell nucleus and started the production of new proteins. This, in turn, brought about a change in the form and function of the synapse. What we call memory is, thus, elicited by direct changes in the billion of synapses that form the contact points between the nerve cells.

I am convinced that you and I will remember this Nobel ceremony for many years. This is because of the dopamine which Arvid Carlsson discovered, enabling the brain to react to what we see and hear; the second messengers that Paul Greengard described, carrying the signals into the nerve cell; and the memory functions that Eric Kandel found to be due to changes in the very form and function of the synapses.

Dear Arvid Carlsson, Paul Greengard and Eric Kandel. Your discoveries concerning "signal transduction in the nervous system" have truly changed our understanding of brain function. From Arvid Carlsson's research we now know that Parkinson's disease is due to failure in synaptic release of dopamine. We know that we can substitute the lost function by a simple molecule, L-DOPA, which replenishes the emptied stores of dopamine and in this way, give millions of humans a better life.

We know from Paul Greengard's work how this is brought about. How second messengers activate protein kinases leading to changes in cellular reactions. We begin to see how phosphorylation plays a central part in the very orchestration of the different transmitter inputs to the nerve cells.

Finally, Eric Kandel's work has shown us how these transmitters, through second transmitters and protein phosphorylation, create short- and long-term memory, forming the very basis for our ability to exist and interact meaningfully in our world.

On behalf of the Nobel Assembly at Karolinska Institutet, I wish to convey our warmest congratulations and I ask you to step forward to receive the Nobel Prize from the hands of His Majesty the King.

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[Photo Credits: The photo of Arvid Carlsson celebrating is from "The Nobel Prize did change my life!" . The photo of Paul Greengard with his wife Ursala von Rydingsvard is from The New York Times. Greengard used his prize money to fund an annual $50,000 award to an outstanding female medical researcher.

Healing Through Quantum Mechanics

 
Jeffrey Shallit at Recursivity posts about a chiropractor in Seattle who will heal you by using quantum mechanics [Your Daily Dose of Woo].

There's a comment on his blog that points to a quack right there in Kitchener/Waterloo who makes the same silly claims. Check it out. I've inserted a picture of the ECLOSION (Electro Physiological Feedback Xrroid) device from the Kuantum Power website. Wouldn't you just love to have one of those? It will even work on computers made by fruit companies.

These are more examples of the misuse of science. How can we combat this except by making sure we educate students properly? Judging by what I see at the University of Toronto, we aren't doing a very good job of teaching students how to think. I get the feeling that most of my colleagues aren't aware of the problem and those that are, don't care. I see lots of similar woo in the scientific literature.

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Misusing Science

 
Canadian Cynic has a new job that forces him to drive past a certain billboard every day [And now, two troublemakers that need no introduction ...].

CC links to the website of the billboard sponsor [Stop the Cover-up]. Here's what you see if you follow the link.


This is group of people who are opposed abortion. What they're saying is that women who choose abortion are more likely to get breast cancer. Specifically ...

It is a well established fact that abortion can increase a woman’s risk of developing breast cancer by denying her the protective effect of both a full-term pregnancy as well as breast-feeding. In addition, the abrupt, artificial termination of a healthy pregnancy leaves a woman with an increased number of vulnerable undifferentiated (immature) breast cells which are, in turn, exposed to the massive amounts of estrogen present during early normal pregnancy. Estrogen is a known cancer causing hormone.

Now, it doesn't take too much exposure to real science to recognize the problem with such claims. What they're doing is taking a little bit of truth and distorting it into something that's not the truth.

This sort of thing is very common these days. Everyone wants to bask in the glow of science even when they are doing their best to extinguish that glow. Everyone wants to have their cake and eat it too.

I hate to bring up the framing issue again but, at the risk of sounding like a broken record, this ad is exactly the sort of thing I fear when Nisbet and Mooney start preaching. There's no question in my mind that this ad is a good example of framing (=spin). I'm not sure how we distinguish between this approach and one were we all agree to use science to support certain policies on climate change, or certain approaches to dealing with creationism.

At what point do we draw the line between truth and lies? Who is going to be the judge of when that line is crossed?

UPDATE: Abortion and Breast Cancer: There Is no Link.

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You're Not Gonna Believe This ...

 

According to Bill Dembski [Who’s in it for the money?].

Darwinism has always been an upper-class movement. ID, by contrast, is strictly middle-class. That’s our base and that’s where we find our support.

You won't believe his evidence for such a statement unless you actually follow the link and read what he wrote.

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Atheists in the Media

 
Come to the Centre for Inquiry's lecture by Wodek Szemberg on the role of atheists in the media. [Why So Few Atheists in the Media?].

Email me if you'd like to attend. Maybe we could meet at my office and get together for something to eat before walking to the Centre for Inquiry on Beverley St.? I'm certainly going to ask him about the "Best Lecturer" series. That should be fun.

SPECIAL EVENT: Why So Few Atheists in the Media? with TVO The Agenda Producer

Starts
Friday, May 9th at 7:00 pm
Ends
Friday, May 9th at 9:00 pm
Location
Centre for Inquiry Ontario, 216 Beverley St., Toronto, ON M5T 1Z3, 1 minute south of College St. at St. George St.

Wonder why secular humanists aren't included on every media ethics panel which includes the perspectives of just about everyone else?

INFLUENTIAL TV PRODUCER DISCUSSES ATHEIST & HUMANIST MARGINALIZATION IN THE MEDIA AND SUGGEST NEW STRATEGIES

Special FREE Event!

Featuring Wodek Szemberg, TV Ontario Producer of The Agenda with Steve Paiken, Best Lecturer Competition and BIG IDEAS, and "out of the closet" atheist.

Everyone is welcome.

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Skepticast #145: Should Biology Students Pass the Course If They Don't Understand the Science?

 
Steven Novella (photo) is a skeptic and a neurologist at Yale University School of Medicine. He publishes a podcast called Skeptics Guide to the Universe. In the April 30th edition he discusses the proposed Florida Laws on "Academic Freedom" with Bob Novella, Evan Bernstein, and Jay Novella [Skepticast #145].

About one quarter of the way into the podcast they turn their attention to the issue of educating creationists at university. They discuss my views on the subject as described in Do Fundamentalist Christians Actively Resist Learning?. Here's what I said ...

Keeping all these cautions in mind, it is still quite remarkable that some significant percentage of fundamentalist Protestants can go to college and still reject the basic scientific fact that humans evolved. Note that in all of the other groups the college educated subset are more inclined to accept evolution. (Do most of those "college" educated fundamentalists go to some cheap reproduction of a college run by a religious organization?)

As we've seen time and time again on the blogs (and elsewhere), the Christian fundamentalists have erected very strong barriers against learning. It really doesn't matter how much they are exposed to rational thinking and basic scientific evidence. They still refuse to listen.

This is one of the reasons why I would flunk them if they took biology and still rejected the core scientific principles. It's not good enough to just be able to mouth the "acceptable" version of the truth that the Professor wants. You actually have to open your mind to the possibility that science is correct and get an education. That's what university is all about.

Of course, we all recognize the problem here. How do you distinguish between a good Christian who is lying for Jesus and one who has actually come to understand science? It seems really unfair to flunk the honest students who admit that they still reject science and pass the dishonest ones who hide their true beliefs.

I stand by this statement.

Let's take a simple example. Imagine that you are teaching a course in history and you assign readings about the holocaust. On the exam you ask students to describe the history of Nazi occupied areas of Europe from 1940-1945. Imagine that a student describes all of the historical facts that you have taught in class but then rejects them by denying that the holocaust ever happened. The student claims that belief in the holocaust goes against the student's religious convictions. Should the student be given a passing grade in order to avoid discriminating against religious beliefs?

What if you are a Professor of Medicine at Yale University? Imagine teaching a course on basic neurology and the treatment of, say, Parkinson's disease. What would you do about Scientology students who can recite correctly all of the data on effective drug treatment but then reject it all because it conflicts with their religion? Should they still get an M.D. degree? Is evidence based medicine a requirement or can it be sacrificed when it conflicts with sincerely held beliefs?

Imagine that you are teaching a geology class and as part of the exam you ask students to give the age of the Earth and explain the evidence supporting that age. Let's say a student describes the radiometic data correctly but then goes on to reject the 4.5 billion year old Earth because it conflicts with the Bible. This student insists that the Earth is less than 10,000 years old in spite of the scientific evidence. Should that student get a passing grade on the exam on the grounds that flunking them would be religious discrimination?

I'm sure you can make up similar scenarios involving the common ancestry of humans and other apes.

Here's the question. We flunk students who cannot demonstrate that they understand the material and the scientific facts. Should we make an exception for those students who claim that their ignorance is part of their religion?

Listen to the debate between Steven Novella and his friends. Part of the problem is their concept of what "understanding" the material really means. They think that as long as you can correctly regurgitate the words of the textbook then you have demonstrated understanding. That should be sufficient to pass the course. Do you agree with them?

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{Hat Tip: BigHeathenMike]

Reserpine

Reserpine is a powerful plant alkaloid that used to be used to control psychotic behavior and treat certain cancers. Unfortunately, it's severe side effects and unpredictable behavior has limited it's usefulness. The drug has been replaced by more reliable treatments.

Many plants contain mildly toxic alkaloids but in most cases the concentrations are not high enough to cause a problem.¹ Reserpine is concentrated in Rauwolfia serpentina (Indian snakeroot) and this plant has been used for several thousand years in treating a number of aliments. One of the main effects of reserpine is to block the action of dopamine. This blockage causes symptom's that resemble Parkinson's disease. They can be relieved by treating the patient with L-dopa [Monday's Molecule #70].

My first exposure to research was a summer job (1966) in the lab of George Setterfield at Carleton University in Ottawa (Canada). The project was to identify crystal-like inclusions in the cells of Rauwolfia serpentina. The hypothesis was that these inclusions were composed of alkaloids, especially reserpine. As I recall, I didn't make much progress. The inclusions weren't always visible and my suspicion was that they could have been an artifact of the fixation process.

I haven't been able to find any mentions of plant alkaloid inclusions in the literature. Does anyone know this field?

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1. It's much safer to eat meat.

Terms & Conditions on Nature Network

 
Eva Amsen has an interesting question about how you would fund research if you were in complete control of all the money in the world [see, Would you rather?].

I was all set to post a comment when I realized that I had to sign in to Nature Network in order to do so. That reminded me about the terms and conditions. That's way more hassle than I'm prepared to put up with. I prefer the rough and tumble of unrestricted blogs.

My question is, does anyone else feel this way? What's the future of science blogging? Is it the strictly controlled environment of Nature Networks where the fora are part of a for-profit venture? Or is it the free-for-all environment of some of the other science blogs? Or is it something in between like the relatively unrestricted environment of the blogs run by SEED magazine?

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