title: Ammonium is a key determinant on the dietary restriction of yeast chronological aging in culture medium.
abstract: New evidences have recently emerged from studies in yeast and in higher eukaryotes showing the importance of nutrient balance in dietary regimes and its effects on longevity regulation.We have previously shown that manipulation of ammonium concentration in the culture and/or aging medium can drastically affect chronological lifespan (CLS)of Saccharomyces cerevisiae, especially in amino acid restricted cells. Here we describe that the CLS shortening under amino acid restriction can be completely reverted by removing ammonium from the culture medium. Furthermore, the absence of ammonium, and of any rich nitrogen source, was so effective in extending CLS that no beneficial effect could be observed by further imposing calorie restriction conditions. When present in the culture medium,ammonium impaired the consumption of the auxotrophy-complementing amino acids and caused in an improper cell cycle arrest of the culture.TOR1 deletion reverted ammonium effects both in amino acid restricted and non-restricted cultures, whereas, Ras2p and Sch9p seem to have only a milder effect in the mediation of ammonium toxicity under amino acid restriction and no effect on non-restricted cultures.Our studies highlight ammonium as a key effector in the nutritional equilibrium between rich and essential nitrogen sources and glucose required for longevity promotion.
authors.affiliation: Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Braga, Portugal.|ICVS/3B's - PT Government Associate Laboratory, Braga, Guimarães, Portugal.
authors.forename: Júlia
authors.initials: J
authors.lastname: Santos
authors.affiliation: Molecular and Environmental Biology Centre (CBMA), Department of Biology, University of Minho, Braga, Portugal.
authors.forename: Fernanda
authors.initials: F
authors.lastname: Leitão-Correia
authors.affiliation: Molecular and Environmental Biology Centre (CBMA), Department of Biology, University of Minho, Braga, Portugal.
authors.forename: Maria João
authors.initials: MJ
authors.lastname: Sousa
authors.affiliation: Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Braga, Portugal.|ICVS/3B's - PT Government Associate Laboratory, Braga, Guimarães, Portugal.
authors.forename: Cecília
authors.initials: C
authors.lastname: Leão
mesh_terms: D000596:Amino Acids / Q000378:metabolism; D064751:Ammonium Compounds / Q000378:metabolism* / Q000633:toxicity; D001431:Bacteriological Techniques; D031204:Caloric Restriction; D059447:Cell Cycle Checkpoints; D003470:Culture Media / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism; D008136:Longevity; D019869:Phosphatidylinositol 3-Kinases / Q000235:genetics / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism; D013997:Time Factors; D018631:ras Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D000596:Amino Acids; D064751:Ammonium Compounds; D003470:Culture Media; D005947:Glucose; D019869:Phosphatidylinositol 3-Kinases; D017346:Protein Serine-Threonine Kinases; D029701:Saccharomyces cerevisiae Proteins; D018631:ras Proteins; C083324:TOR1 protein, S cerevisiae; C530964:SCH9 protein, S cerevisiae; C489015:RAS2 protein, S cerevisiae
keywords: amino acid restriction; ammonium; dietary restriction; lifespan; yeast