Un­lock­ing the body clock

The Week (US) - - News 19 -

Three Amer­i­can sci­en­tists have won the No­bel Prize in phys­i­ol­ogy or medicine for their work on cir­ca­dian rhythms, the in­ter­nal bi­o­log­i­cal clock that con­trols a liv­ing or­gan­ism’s be­hav­ior and phys­i­ol­ogy. The rhythms, which are syn­chro­nized with the Earth’s ro­ta­tion, gov­ern a slew of crit­i­cal func­tions, in­clud­ing me­tab­o­lism, blood pres­sure, body tem­per­a­ture, and hor­mone lev­els. While peo­ple have been aware of the body’s “in­ner clock” for cen­turies, the three No­bel lau­re­ates—Jef­frey Hall, Michael Ros­bash, and Michael Young—iden­ti­fied the mech­a­nisms be­hind it. Work­ing with fruit flies, they iso­lated a gene that en­codes a pro­tein that ac­cu­mu­lates in cells at night but de­grades dur­ing the day. They later iden­ti­fied two other genes that con­trib­ute to this process. Their find­ings help ex­plain why con­sis­tently over­rid­ing cir­ca­dian rhythms—by work­ing night shifts or ex­pos­ing your­self to light from com­puter screens at night—could in­crease the risk for chronic health is­sues, in­clud­ing heart dis­ease, obe­sity, cancer, and Alzheimer’s. “We learned we are truly rhyth­mic or­gan­isms,” Young tells The Wash­ing­ton Post. “It’s hard to find a cell that does not os­cil­late in re­sponse to these clocks.”

re­search sug­gests he may have been right. There are cur­rently two com­pet­ing the­o­ries on the ori­gins of life. The Dar­win school of thought posits that dur­ing Earth’s early days, me­te­orites from the so­lar sys­tem de­posited com­pounds that led to the for­ma­tion of RNA, a com­pound sim­i­lar to DNA. The other the­ory is that life orig­i­nated much later, in min­eral-rich hy­dro­ther­mal vents on the ocean floor. To ex­plore the plau­si­bil­ity of the for­mer, re­searchers cre­ated a com­pre­hen­sive model that ac­counted for the as­tro­nom­i­cal, ge­o­log­i­cal, chem­i­cal, and bi­o­log­i­cal con­di­tions of early Earth. They cal­cu­lated that tepid, shal­low ponds all over the planet could have en­abled the es­sen­tial com­po­nents of nu­cleo­tides to bond, re­con­fig­ure, and even­tu­ally form long strands of RNA. The re­searchers be­lieve this process took place at least 4.17 bil­lion years ago— mil­lions of years be­fore the ap­pear­ance of the ear­li­est known life. But pro­po­nents of the hy­dro­ther­mal vent the­ory re­main un­con­vinced, ar­gu­ing it’s un­likely the pre­cur­sor com­pounds could have sur­vived the me­te­orite im­pact. “It’s def­i­nitely an­other piece of ev­i­dence to add to the stacks,” lead au­thor Ben Pearce, from Mc­Mas­ter Univer­sity in Canada, tells Newsweek.com. “It will take a whole [lot] more sci­ence to really nail this down.”

they had nor­mal brain func­tion when the study be­gan. The worse their per­for­mance on the smell test, the higher their risk. “This is not a sim­ple, sin­gle-vari­able test for the risk of de­men­tia,” re­searcher Jayant Pinto tells The New York Times. “But sen­sory func­tion is an in­di­ca­tor of brain func­tion. When sen­sory func­tion de­clines, it can be a sig­nal to have a more de­tailed ex­am­i­na­tion to see if ev­ery­thing’s OK.”

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