Tuesday, December 01, 2009


Coral soaks up the UV rays to protect the reef citizens.

UV has a habit of zapping DNA and triggering thymine dimers, pretty much irreversible snags in the flowing template of life. Apparently that calcium carbonate isn't just for swanky-looking underwater condominiums, it can protect in any form right down to ground up slurry.

Monday, November 30, 2009

Running down rogue cells with the handcuffs.

Zapping cancer cells with magnetic nanodiscs.

Reminds me of this obscure JLA character named Pulse 8, who could drop attach these discs to people magnetically and then increase the weight exponentially.

Saturday, November 28, 2009

Monday, November 23, 2009

A turkey never voted for an early Christmas or a biochemical albatross

I always remember a Seinfeld episode where Jerry and George become addicted to playing with an antique toy collection belonging to Jerry's girlfriend, and use wine and turkey to drug her into naps. What's that thing in turkey that makes you sleepy, George and Jerry? Tryptophan!

So it hazards a chance that sometime after your family Thanksgiving meal, when the kids have long left the table and the Detroit Lions are embarrassing themselves in their lone annual national appearance, someone will look around at the clan, delirious from a giant meal and trot out an old trope as to why all the logy faces - that mischievous, impish molecule - tryptophan - has put us all to sleep, said to be found in titanic proportions in that marquis entree, the turkey.

Tryptophan myths and what really brings you down on Happy T - the technical term being post-prandial somnolence - have been running around the Thanksgiving table like chummy cousins for at least the last twenty five years. But indeed, there's little credence to the idea tryptophan is an ultimate torpor torpedo.

Tryptophan is one of those 20 essential molecules called amino acids that humans need to find in their diet as the body lacks sufficient metabolic machinery to effectively create them from other materials. Amino acids are the building blocks of peptides or more commonly, proteins of all styles which make up you and me and buffaloes, Venus flytraps and the H1N1 influenza virus. The amino acids are all like various types of construction material with their own individual character. Some make loops and some make bends, others are straight and others have side chains like branches of a tree, sticking out in various means to provide all sorts of flavor to your protein creation. Tryptophan also offers some other uses to living things, being a precursor of plant-growing hormones called auxins or the essential nutrient niacin, Vitamin B3. A variant of tryptophan is even used by the curious cone snail as a component of its venom, contryphan, a neurotoxin it can jab into prey with its harpoon-like tongue called a radula.

The seed of this myth likely comes from a series of experiments at Oxford University where people were asked to drink a special amino acid mixture and then have them participate in the Prisoner's Dilemma, a game based on mutual cooperation. As players were deprived of tryptophan in their drink, indeed, those players will significantly less likely to cooperate. So there does appear to be a biochemical underpinning to the myth. Tryptophan is the substrate, or starting material for the synthesis of serotonin and in turn, melatonin, neurotransmitters both of which have a hand in regulating our circadian rhythm and need for sleep. From here it's just an irrational but tempting leap to conclude that big delicious bird is going to put you down for a few hours as it jams your head full of sleepy chemicals.

But that's not the end of the story.

While you can find tryptophan in turkey, there's no more per gram of protein than you'd find in chicken or cod or even beef. Indeed, there are a multitude of foods where tryptophan racks up in abundance including milk, eggs, soybeans and sesame seeds. You'd soak your system in tryptophan at about double the rate if you drank milk at equal levels you ate turkey. To go even further, tryptophan is the least abundant amino acid commonly found in natural protein, so as you load all that turkey into our guts, tryptophan has to get into the brain by the same blood-brain barrier gateways as all the other, far more abundant proteins. The stunning fact is your tryptophan levels in your brain (and thus, able to sing its psychotropic lullaby) will actually decrease with a meat-rich Thanksgiving meal of any stripe.

So chances are good that not only are the tryptophan levels in turkey insufficient to trigger a sleepy state in their best cases, they likely never get anywhere near a location of effect due to the giant protein meal actually depleting tryptophan levels as the large quantity aminos bull their way into the brain.

A better culprit of that bloaty corpse feeling? Those dreaded carbs.

It's a well-established fact in multiple animal models and human experiments that ingesting large volumes of carbohydrates provokes the release of insulin into the bloodstream. Insulin promotes the absorption of of branched amino acids, specifically large neutral branched chain amino acids into the muscle, but not tryptophan. This leaves tryptophan in the blood without competition as we saw earlier to get through that blood-brain barrier gateway. Once in the brain, then the raphe nuclei - the serotonin factories of the brain suddenly get a big shipment of tryptophan, convert it into serotonin and then to melatonin, the master sleep neurohormone,in the pineal gland, and turn the lights out. While tryptophan is a player in this model, it is those helpings of potatoes, stuffing, cranberry sauce and pie that put you down on the couch until those Turducken drumsticks are handed out to whomever whipped the Lions that day.

Tryptophan was actually marketed in the late 1980's as a diet supplement, boasted as a cure-all for depression, seasonal affective disorder, hypertension, obesity and even obsessive-compulsive disorder. A contaminated batch of L-tryptophan that led to the disability of hundreds and the deaths of 37 people, triggering a ban from the FDA in 1991. After the dust had settled and the contamination well-characterized, the FDA scaled back the ban in 2001 but still expressed skepticism:

"Based on the scientific evidence that is available at the present time, we cannot determine with certainty that the occurrence of EMS in susceptible persons consuming L-tryptophan supplements derives from the content of L-tryptophan, an impurity contained in the L-tryptophan, or a combination of the two in association with other, as yet unknown, external factors" Link

So enjoy that Happy T this year, take time to listen to grandma, take the Lions lightly, and have fun. But whatever you do, when you begin to feel catatonic, don't blame the tryptophan.

Maybe Jerry's girlfriend is just a lightweight drinker, afterall.

Tuesday, November 17, 2009

Calm down and protect the ticker.

New study finds meditation cuts down heart attack risk.

Sorta reminds me how the Dalai Lama can apparently surge his stem cell count through sheer thought.

Monday, January 05, 2009

Via Pharyngula:

15 Evolutionary Gems: A body of evidence published in the last decade that flexes the considerable intellectual muscle of Evolutionary Theory.

1. The discovery of Indohyus, an ancestor to whales.

2. The discovery of Tiktaalik, an ancestor to tetrapods.

3. The origin of feathers revealed in creatures like Epidexipteryx.

4. The evolution of patterning mechanisms in teeth.

5. The developmental and evolutionary origin of the vertebrate skeleton.

6. Speciation driven indirectly by selection in sticklebacks.

7. Selection for longer-legged lizards in Caribbean island populations.

8. A co-evolutionary arms race between Daphnia and its parasites.

9. Non-random dispersal and gene flow in populations of great tits.

10. Maintenance of polymorphisms in populations of guppies.

11. Contingency in the evolution of pharyngeal jaws in the moray.

12. Developmental genes that regulate the shape of beaks in Darwin's finches.

13. Evolution of regulatory genes that specify wing spots in Drosophila.

14. Evolution of toxin resistance.

15. The concept of evolutionary capacitance: the idea that environmental stress can expose hidden variations that are then subject to selection.

Tuesday, June 17, 2008

Stimulant Surprise

Sometimes you just need that extra oomph to get through the day.

Today's NY Times had an interesting article about the smell of coffee and how that scent alone can have a gene-activating effect on the brain. The reality is the vast majority of our genes are almost always mothballed away, tightly bound to inhibit and regulate their expression by methyl groups and G-C rich zippers. However, get the right stimulant and the cell will release that tight grip and allow amazingly fast transcription of genes to build proteins that in this case, get the brain moving off of sleepy maintenance mode and on to the business of minding...uh, one's business.

Still, one cannot live on stimulants alone, and another research group has shown some compelling evidence for that thing we all likely got in preschool and kindergarten: The afternoon nap. The one real perk I miss from one of my former labs is that the New Age building had nap rooms, and boy did I ever take advantage. A snappy 20 minute snooze around 2pm made not only the rest of the work day but the night as well a time of full production and activity.

Really, those lab sombreros I invented back in grad school make great sense.