Sunday, January 21, 2007
Pass Me a Cold One
It’s a common phenemonon: A cold beer on a hot day gives you more of a buzz than a cold beer on a chilly day. Uncounted numbers of northern tourists have learn this lesson at their peril after a few tequilas in Cozumel. Fruit flies get drunk faster in hot weather, too. Their drink of choice is the decaying flesh of fruit, and fly populations in higher, cooler latitudes can really hold their rotten fruit, compared to their tropical cousins.
Higher temperature alters the detoxification pathways for alcohol and decreases the rigidity of cell membranes. Increased temperature also slows the activity of alcohol dehydrogenase, a primary enzyme involved in breaking down booze in the body. Alcohol is an amphiphilic molecule, meaning that cells treat it like water. So in hot weather, alcohol travels faster and lingers longer in the bodies of both humans and fruit flies.
Geneticist Kristi Montooth and colleagues at Brown University used fruit flies from an Australian site averaging 80 degrees F, and compared their intake of ethanol in solution with the intake of their more alcohol-tolerant cousins from a Tasmanian climate, where the temperature was 59 degrees F. The researchers traced the difference to regulatory proteins that help the flies cope better with alcohol in low temperatures; specifically, the expression of genes controlling fatty acid synthesis. The study was published in the Journal of Experimental Biology.
--Montooth, K.L., et. al. “Membrane lipid physiology and toxin catabolism underlie ethanol and acetic acid tolerance in Drosophila melanogaster. Journal of Experimental Biology. 209 3837-3850. 2006.
--Blackburn, Laura. “Hot Flies, Good Times.” ScienceNOW Daily News. September 15, 2006. http://sciencenow.sciencemag.org/
--Phillips, Kathryn.“Ethanol Tolerance in Temperate Drosophila.”Inside JEB.September 19 2006. http://jeb.biologists.org/cgi/content/full/209/19/iii