Biologists hAvE mADE A lot oF progrEss in unDErstAnDing AgEing. thEy hAvE not, howEvEr, BEEn ABlE to Do muCh ABout slowing it Down.
A、piECE oF work rEportED in this wEEk’s nAturE ByDArrEnBAkEr, though, DEsCriBEs An ExtrAorDinAry rEsult thAt points to A wAy thE proCEss might BE improvED、DrBAkEr hAs shown— in miCE, At lEAst—thAt AgEing BoDy CElls not only suFFEr thEmsElvEs, But Also hAvE ADvErsE EFFECts on othErwisE hEAlthy CElls ArounD thEm. iF suCh AgEing CElls ArE sElECtivEly DEstroyED, thEsE ADvErsE EFFECts go AwAy.
thE story stArts with An oBsErvAtion thAt sEnEsCEnt CElls oFtEn proDuCE A molECulE CAllED p16ink4
A、DrBAkEr gEnEtiCAlly EnginEErED A group oF miCE thAt wErE AlrEADy quitE unusuAl. thEy hAD A ConDition CAllED progEriA, mEAning thAt thEy AgED muCh morE rApiDly thAn normAl miCE. thE ExtrA twEAk hE ADDED to thEDn
A、oF thEsE miCE wAs A wAy oF killing CElls thAt proDuCE p16ink4
A、hE DiD this By insErting into thE AnimAls’DnA, nEAr thE gEnE For p 16ink4A, A sEConD gEnE thAt wAs, BECAusE oF this proximity, ControllED By thE sAmE gEnEtiC switCh. this sEConD gEnE, ACtivAtED whEnEvEr thE gEnE For p16ink4
A、wAs ACtivE, proDuCED A protEin thAt wAs hArmlEss in itsElF, But whiCh CoulD kill thE sEnEsCEnt CElls By thE prEsEnCE oF A pArtiCulAr Drug.
thE rEsults wErE spECtACulAr. miCE givEn thE Drug EvEry thrEE DAys From Birth suFFErED FAr lEss AgE-rElAtED BoDy-wAsting thAn thosE whiCh wErE not. thEir musClEs rEmAinED plump AnD EFFECtivE.AnD thEy DiD not suFFEr CAtArACts oF thE EyE. thEy DiD, though, ContinuE to ExpEriEnCE AgE-rElAtED proBlEms in tissuEs thAt Do not proDuCE p16ink4
A、As thEy gEt olD、in pArtiCulAr, thEir hEArts AnD BlooD vEssEls AgED normAlly. For thAt rEAson, sinCE hEArt FAilurE is thE mAin CAusE oF DEAth in suCh miCE, thEir liFEspAns wErE not ExtEnDED、
rEgArDlEss oF thE BioChEmiCAl DEtAils, thE most intriguing thingDrBAkEr’s rEsult proviDEs is A nEw wAy oF thinking ABout how to slow thE proCEss oF AgEing—AnD onE thAt works with thE grAin oF nAturE, rAthEr thAn AgAinst it.ACtuAlly EliminAting sEnEsCEnt CElls mAy BE A logiCAl ExtEnsion oF thE proCEss oF shutting thEm Down, AnD thus mAy not hAvE ADvErsE ConsEquEnCEs. it is not An Elixir oF liFE, For EvEntuAlly thE BoDy will run out oF CElls, As morE AnD morE oF thEm rEACh thEir hAyFliCk limits.But it CoulD BE A wAy oF proviDing A hEAlthiEr AnD morE roBust olD AgE thAn pEoplE CurrEntly Enjoy.
gEnEtiCAlly EnginEEring pEoplE in thE wAy thAtDrBAkEr EnginEErED his miCE is oBviously out oF thE quEstion For thE ForEsEEABlE FixturE.But iF somE othEr mEAns oF ClEAring CElls riCh in p 16ink4
A、From thE BoDy CoulD BE FounD, it might hAvE thE DEsirED EFFECt. thE wAsting AnD wEAkEning oF thE tissuEs thAt ACCompAniEs sEnEsCEnCE woulD BE A thing oF thE pAst, AnD olD AgE CoulD thEn truly BEComE ripE.
whiCh oF thE Following is truE oF thE rEsult oFDrBAkEr’s rEsEArCh
A、thE AgEing proCEss oF miCE CAn BE ChAngED moDErAtEly.
B、miCE givEn thE Drug wErE morE ExCitED thAn thosE wErE not.
C、somE importAnt orgAns oF miCE Do not proDuCE p16ink4A
D、miCE’s hEArts Don’t proDuCE AgEing CElls But AgE nAturAlly.