Yeast ageing

Abstract

Cilj seminara bio je sustavno opisati dosadašnja znanstvena saznanja o procesima starenja kod pupajućeg kvasca, Saccharomyces cerevisiae. Postoji više mehanizama povezanih sa starenjem. Naglasak je stavljen na dosad najistraženiji protein Sir2 (od engl Silent Information Regulator Two proten) i njegovu ulogu u replikativnom i kronološkom starenju kvasca; Sir2 povezuje nutritivni status stanice i regulaciju sinteze proteina; reagira na omjer [NAD]/[NADH] te u uvjetima kalorijske restrikcije utišava sintezu rRNA. Uloga proteina PKA , Sch9 i TOR povezana je s regulacijom antioksidativne zaštite prilikom prijelaza na oksidativni metabolizam. Procesi starenja nisu uvjetovani jednoznačno, nego ovise o životnim uvjetima i genetičkoj podlozi. Također, još su mnoge stvari vezane uz procese starenja neistražene, a kvasac kao koristan modelni organizam na tom području pruža mnoge mogućnosti u daljnjim istraživanjima.The main goal of the study is to systematically describe ageing process of budding yeast, Saccharomyces cerevisiae. There are several mechanisms of ageing analysed up to now on yeast. Sir2 (Silent Information Regulator Two proten ) is considered as the most important protein in this process. It is involved in both, replicative and chronological ageing of yeast and presents a link between the nutritional state and the regulation of the protein syntesis; it reacts to [NAD]/[NADH] ratio and supress the rRNA shyntesis during calorie restriction. On the other side, signalling pathways involving protein kinase A, TOR and Sch9 are connected with regulation of antioxidative protection during diauxic shift. In conclusion, ageing process in yeast is not determined, but it depends on living conditions and genetic background. Many processes involved in ageing are still unknown. More careful analysis of age-associated phenotypes and related mechanisms will extend research in the field of budding yeast ageing