Mbiri ya kulengedwa kwa chiphunzitso cha Hayflick
Leonard Hayflick (wobadwa pa May 20, 1928 ku Philadelphia), pulofesa wa anatomy pa yunivesite ya California ku San Francisco, anayamba chiphunzitso chake pamene ankagwira ntchito ku Wistar Institute ku Philadelphia, Pennsylvania, mu 1965. Frank MacFarlane Burnet anatcha chiphunzitsochi pambuyo pa Hayflick buku lake lakuti Internal Mutagenesis, lofalitsidwa mu 1974. Lingaliro la malire a Hayflick linathandiza asayansi kufufuza zotsatira za ukalamba wa maselo m’thupi la munthu, kukula kwa maselo kuchokera pa siteji ya umbryonic mpaka imfa, kuphatikizapo zotsatira za kufupikitsa utali wa malekezero a kromozomu wotchedwa telomeres.
Mu 1961, Hayflick anayamba kugwira ntchito ku Wistar Institute, kumene anaona mwa kuona kuti maselo aumunthu samagawanika mpaka kalekale. Hayflick ndi Paul Moorehead adalongosola chodabwitsa ichi mu monograph yotchedwa Serial Cultivation of Human Diploid Cell Strains. Ntchito ya Hayflick ku Wistar Institute idapangidwa kuti ipereke yankho lazopatsa thanzi kwa asayansi omwe adayesa mayeso pasukuluyi, koma nthawi yomweyo Hayflick adachita kafukufuku wake pazotsatira za ma virus m'maselo. Mu 1965, Hayflick adafotokozanso za lingaliro la malire a Hayflick mu monograph yotchedwa "Limited Lifespan of Human Diploid Cell Strains in the Artificial Environment".
Hayflick anafika ponena kuti selo imatha kumaliza mitosis, mwachitsanzo, njira ya kubalana mwa magawano, nthawi makumi anayi mpaka makumi asanu ndi limodzi, kenako imfa imapezeka. Mfundo imeneyi inakhudza mitundu yonse ya maselo, kaya akuluakulu kapena majeremusi. Hayflick adapereka lingaliro loti kutha kocheperako kwa selo kumalumikizidwa ndi kukalamba kwake komanso, molingana ndi kukalamba kwa thupi la munthu.
Mu 1974, Hayflick adayambitsanso National Institute on Aging ku Bethesda, Maryland.
Bungweli ndi nthambi ya US National Institutes of Health. Mu 1982, Hayflick adakhalanso wachiwiri kwa wapampando wa American Society for Gerontology, yomwe idakhazikitsidwa mu 1945 ku New York. Pambuyo pake, Hayflick adagwira ntchito kufalitsa chiphunzitso chake ndikutsutsa chiphunzitso cha Carrel cha kusafa kwa ma cell.
Kutsutsa chiphunzitso cha Carrel
Alexis Carrel, dokotala wa opaleshoni wa ku France yemwe ankagwira ntchito ndi minofu ya mtima wa nkhuku kumayambiriro kwa zaka za m'ma XNUMX, ankakhulupirira kuti maselo amatha kuberekana mpaka kalekale pogawanika. Carrel adanena kuti adatha kukwaniritsa kugawanika kwa maselo a mtima wa nkhuku muzakudya zopatsa thanzi - ndondomekoyi inapitirira zaka zoposa makumi awiri. Zimene anachita pofufuza minofu ya mtima wa nkhuku zinalimbikitsa chiphunzitso chakuti ma cell agawanika mosalekeza. Asayansi ayesa mobwerezabwereza kubwereza ntchito ya Carrel, koma kuyesa kwawo sikunatsimikizire "kutulukira" kwa Carrel.
Kutsutsa chiphunzitso cha Hayflick
M'zaka za m'ma 1990, asayansi ena, monga Harry Rubin ku yunivesite ya California ku Berkeley, adanena kuti malire a Hayflick amangogwira ntchito ku maselo owonongeka. Rubin adanenanso kuti kuwonongeka kwa ma cell kungayambike chifukwa ma cell amakhala m'malo osiyana ndi malo awo oyamba m'thupi, kapena asayansi amawulula ma cell omwe ali mu labu.
Kufufuza kwina pazochitika za ukalamba
Ngakhale amatsutsidwa, asayansi ena agwiritsa ntchito chiphunzitso cha Hayflick monga maziko a kafukufuku wowonjezereka wokhudza kukalamba kwa ma cell, makamaka ma telomere, omwe ndi magawo omaliza a ma chromosome. Ma telomere amateteza ma chromosome komanso amachepetsa masinthidwe a DNA. Mu 1973, wasayansi wa ku Russia A. Olovnikov anagwiritsa ntchito chiphunzitso cha Hayflick cha imfa ya selo mu maphunziro ake a malekezero a ma chromosome omwe samadzibala okha panthawi ya mitosis. Malingana ndi Olovnikov, ndondomeko ya kugawanika kwa maselo imatha mwamsanga pamene selo silingathe kuberekanso malekezero a ma chromosome ake.
Chaka chotsatira, mu 1974, Burnet anatcha chiphunzitso cha Hayflick kuti Hayflick malire, pogwiritsa ntchito dzinali mu pepala lake, Internal Mutagenesis. Pamtima pa ntchito ya Burnet inali kuganiza kuti ukalamba ndi chinthu chokhazikika m'maselo amitundu yosiyanasiyana ya moyo, ndikuti ntchito yawo yofunika imagwirizana ndi chiphunzitso chotchedwa Hayflick malire, chomwe chimakhazikitsa nthawi yakufa kwa chamoyo.
Elizabeth Blackburn wa pa yunivesite ya San Francisco ndi mnzake Jack Szostak wa ku Harvard Medical School ku Boston, Massachusetts, anatembenukira ku chiphunzitso cha malire a Hayflick m’maphunziro awo a kapangidwe ka ma telomere mu 1982 pamene anapambana kupanga cloning ndi kudzipatula ma telomere.
Mu 1989, Greider ndi Blackburn anatenga sitepe yotsatira pophunzira zochitika za ukalamba wa maselo mwa kupeza puloteni yotchedwa telomerase (enzyme yochokera ku gulu la transferases yomwe imayang'anira kukula, chiwerengero ndi nucleotide kapangidwe ka chromosome telomeres). Greider ndi Blackburn anapeza kuti kukhalapo kwa telomerase kumathandiza maselo a thupi kupewa kufa mwadongosolo.
Mu 2009, Blackburn, D. Szostak ndi K. Greider analandira Mphotho ya Nobel mu Physiology kapena Medicine ndi mawu akuti "chifukwa chotulukira njira zotetezera ma chromosome ndi ma telomeres ndi enzyme telomerase." Kafukufuku wawo adatengera malire a Hayflick.