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Yet another one of my geeky post.  Consider the national highway traffice safety adminstiration estimates that 20% of the motor vehicle crashes are due to over-worked (not drunk) and sleepy drivers, knowing how sleepy before you hit the gas may save other people’s lives (not yours).  If you ever wonder what might a series of tests a futuristic car would perform before the ignition is unlocked, this is certainly going to be one of them. 

An article in December issue of the Proceedings of the National Academy of Sciences of the USA (here PNAS or short) by L Seugnet, J Boero and colleagues suggests Amylase, a ubiquitous enzyme in your mouth, could serve as a biomarker for excessive sleep deprivation!  They first noticed in flies, increased sleep deprivation is associated with increase in mRNA expression of Amylase.  Then, they ruled out the possibilities of amylase being associated with just waking or it mechanistically is not a causative agent of sleepiness.  Finally, they were able to show humans with long hours of sleep deprivation also showed increase in Amylase activity (not total protein). 
Interestingly, they had to squash a bunch of fruit-fly heads to get the measurement and only easy swab for humans.  Talking about serious double standards here.  poor flies, sleep-deprived and headless…

Ref: Laurent Seugnet et al, 2006 Dec 26;103(52):19913-8.

We (humans) often think very human-centrically (no surprise given our
predisposition).  The universe must be surrounding us.  The sun is
circling the earth.  And, fruits got to be sweet for we won’t cultivate
it if it’s unpleasant.  But what is pleasant? Something pleasant for us
is simply a chemical reaction, a binding of the odor molecule to our
sensory nervous neurons that sends a signal to our brain’s reward center
and generates a release of "happiness" (similar to the breast
feeding sensation (oxytocin-driven) or getting a pat on the shoulder(dopamine-driven) behavior)…That’s pleasant my
friends.  Similarly, pleasant smell to bugs may not have to be flowery
or sweet… it could be rotten flesh… in fact many plants in the
southeast Asia do produce flowers that offer a offensive odor of rotten
meat.  Hey… doesn’t really matter if the flies or bees are doing the
pollination right?

But the real question is why do we have so little "stinky" flowers and lot of "pleasantly fragrant" flowers?  Is it because we’re the dominating species? not really for there are purely more insects than animals and a wide variety of habitats (some inhabitable by animals).  Why is this? Or did evolution just took a chance and decided this one form of smell is to dominate the planet?