Evolution of sensory signaling

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How we sense the world has, ultimately, a cellular and molecular basis. We have these big brains that do amazingly sophisticated processing to interpret the flood of sensory information pouring in through our eyes, our skin, our ears, our noses…but when it gets right down to it, the proximate cause is the arrival of some chemical or mechanical or energetic stimulus at a cell, which then transforms the impact of the external world into ionic and electrical and chemical changes. This is a process called sensory signaling, or sensory signal transduction.

While we have multiple sensory modalities, with thousands of different specificities, many of them have a common core. We detect both light and odor (and our cells also sense neurotransmitters) with similar proteins: they use a family of G-protein-linked receptors. What that means is that the sensory stimulus is received by a receptor molecule specific for that stimulus, which then actives a G-protein on the intracellular side of the cell membrane, which in turn activates an effector enzyme that modifies the concentration of second messenger molecules in the cell. Receptors vary—you have a different receptor for each molecule you can smell. The effector enzymes vary—it can be adenylate cyclase, which changes the levels of cyclic AMP, or it can be phospholipase C, which generates other signalling molecules, DAG and IP3. The G-protein that links receptor and effector is the common element that unites a whole battery of senses. The evolutionary roots of our ability to see light and taste sugar are all tied together.

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One partisan Republican down

The Commissar is voting Democratic this fall.

On the one hand, I’m not too impressed. It’s taken him long enough to realized that the Spoiled Child Presidency of GW Bush has been a catastrophe—the signs have all been there since before the 2000 election, and we moonbats have been called “Bush-haters” rather than perceptive.

On the other hand, I sympathize with something: the reluctance to support the Democratic party. While my contempt for Bush and the modern Republican agenda has grown, so has my disgust with the gutless, unprincipled Lords of the DNC. It’s hard to blame the Commissar for failing to see the flaws of our president when the opposition party has been so incompetent and so inarticulate that it has failed itself to express those problems and propose alternatives.

The unauthorized autobiography of George W. Bush

I get a lot of mail from publishers, and this one had me going for a moment…one thing I don’t get is much mail from right-wing sources (other than the usual excoriations, of course.) This one looks so much like authentic Republican PR that it took a moment for it to sink in.

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Speaking from the heart, not from the brain, this legendary Commander-in-Chief takes us on a journey through his momentous life. The great man we hear here displays his mother’s steely resolve and vindictive temper, his father’s keen mastery of language, and his own unique gift of deciding.

That’s a work of genius…satire that sneaks up on you. I almost trashed it before I realized what it was.

Don’t miss the movie! I may have to buy the book.

And the Nobel goes to…

Andrew Fire and Craig Mello, for the discovery of RNAi. Read Pure Pedantry for an explanation for why this is important.


I’ll also mention that Carl Zimmer presents his take on this award…and wouldn’t you know it, evolution has its greasy fingerprints all over it.


I must also promote an excellent comment from Andy Groves:

I’ve said it before, and I’ll say it again for the benefit of ID supporters out there – this is what a real scientific revolution looks like. Fire and Mello published their paper in 1998 (two years after “Darwin’s Black Box” came out, for those who are interested). Since then, the number of primary research papers on RNAi, siRNAs and miRNAs stands at 12399, using the search terms

(RNAi OR siRNA OR miRNA) NOT review

12400 papers in eight years. That’s 1550 a year, or just over four papers a day. Would Bill Dembski, the Isaac Newton of information theory, care to comment?

Hmmm?

Every science paper, every bit of recognition given to working scientists, seems to be a rather nasty rebuke to the promulgators of creationism.

Our duty

Jim Macdonald offers some excellent advice to military personnel over at Making Light.

Article 3 of the Geneva Conventions is straightforward and clear. Under Article VI of the Constitution, it forms part of the supreme law of the land.

You personally will be held responsible for all of your actions, in all countries, at all times and places, for the rest of your life. “I was only following orders” is not a defense.

What all this is leading to:

If you are ordered to violate Article 3 of the Geneva Conventions, it is your duty to disobey that order. No “clarification,” whether passed by Congress or signed by the president, relieves you of that duty.

If you are ordered to violate Article 3 of the Geneva Conventions, this is what to do:

  1. Request that your superior put the order in writing.

  2. If your superior puts the order in writing, inform your superior that you intend to disobey that order.

  3. Request trial by courtmartial.

You will almost certainly face disciplinary action, harassment of various kinds, loss of pay, loss of liberty, discomfort and indignity. America relies on you and your courage to face those challenges.

We, the people, need you to support and defend the Constitution. I am certain that your honor and patriotism are equal to the task.

I’m just curious—is this information given to soldiers as part of basic training? If not, shouldn’t this be printed out and handed to our troops as they are embarking to Iraq and Afghanistan?

Maybe we should send a copy to GW Bush, too. I don’t think he understands it.

What our kids need to know

Since John Wilkins has already commented on Paul Hanle’s article on the declining competitiveness of Americans in science, I’ll focus my opinion on a narrower point. I think Hanle is precisely correct when he points out that ID and creationism are shackles that handicap science education in our country.

By teaching intelligent design or other variants of creationism in science classes at public schools — or by undercutting the credibility of evolution — we are greatly diminishing our chances for future scientific breakthroughs and technological innovations, and are endangering our health, safety and economic well-being as individuals and as a nation.

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