scholarly journals Caloric restriction rescues yeast cells from alpha-synuclein toxicity through autophagic control of proteostasis

Aging ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 3821-3833 ◽  
Author(s):  
Belém Sampaio-Marques ◽  
Hélder Pereira ◽  
Ana R. Santos ◽  
Alexandra Teixeira ◽  
Paula Ludovico
Keyword(s):  
Caloric Restriction ◽  
Alpha Synuclein ◽  
Yeast Cells

scholarly journals In S. cerevisiae hydroxycitric acid antagonizes chronological aging and apoptosis regardless of citrate lyase

APOPTOSIS ◽  
2020 ◽  
Vol 25 (9-10) ◽  
pp. 686-696
Author(s):  
Maurizio D. Baroni ◽  
Sonia Colombo ◽  
Olivier Libens ◽  
Rani Pallavi ◽  
Marco Giorgio ◽  
...  
Keyword(s):  
Caloric Restriction ◽  
Mechanistic Model ◽  
Yeast Cells ◽  
Signal Pathways ◽  
Atp Citrate Lyase ◽  
Chronological Aging ◽  
Hydroxycitric Acid ◽  
Age Related ◽  
Citrate Lyase ◽  
Bona Fide

Abstract Caloric restriction mimetics (CRMs) are promising molecules to prevent age-related diseases as they activate pathways driven by a true caloric restriction. Hydroxycitric acid (HCA) is considered a bona fide CRM since it depletes acetyl-CoA pools by acting as a competitive inhibitor of ATP citrate lyase (ACLY), ultimately repressing protein acetylation and promoting autophagy. Importantly, it can reduce inflammation and tumour development. In order to identify phenotypically relevant new HCA targets we have investigated HCA effects in Saccharomyces cerevisiae, where ACLY is lacking. Strikingly, the drug revealed a powerful anti-aging effect, another property proposed to mark bona fide CRMs. Chronological life span (CLS) extension but also resistance to acetic acid of HCA treated cells were associated to repression of cell apoptosis and necrosis. HCA also largely prevented cell deaths caused by a severe oxidative stress. The molecule could act widely by negatively modulating cell metabolism, similarly to citrate. Indeed, it inhibited both growth reactivation and the oxygen consumption rate of yeast cells in stationary phase. Genetic analyses on yeast CLS mutants indicated that part of the HCA effects can be sensed by Sch9 and Ras2, two conserved key regulators of nutritional and stress signal pathways of primary importance. Our data together with published biochemical analyses indicate that HCA may act with multiple mechanisms together with ACLY repression and allowed us to propose an integrated mechanistic model as a basis for future investigations.

scholarly journals Mechanisms that Link Chronological Aging to Cellular Quiescence in Budding Yeast

2020 ◽  
Vol 21 (13) ◽  
pp. 4717
Author(s):  
Karamat Mohammad ◽  
Jennifer Anne Baratang Junio ◽  
Tala Tafakori ◽  
Emmanuel Orfanos ◽  
Vladimir I. Titorenko
Keyword(s):  
Caloric Restriction ◽  
Budding Yeast ◽  
Yeast Cells ◽  
Yeast Culture ◽  
Chronological Aging ◽  
Quiescent Cells ◽  
Cellular Events ◽  
Age Related ◽  
Calorie Diet ◽  
Cellular Quiescence

After Saccharomyces cerevisiae cells cultured in a medium with glucose consume glucose, the sub-populations of quiescent and non-quiescent cells develop in the budding yeast culture. An age-related chronology of quiescent and non-quiescent yeast cells within this culture is discussed here. We also describe various hallmarks of quiescent and non-quiescent yeast cells. A complex aging-associated program underlies cellular quiescence in budding yeast. This quiescence program includes a cascade of consecutive cellular events orchestrated by an intricate signaling network. We examine here how caloric restriction, a low-calorie diet that extends lifespan and healthspan in yeast and other eukaryotes, influences the cellular quiescence program in S. cerevisiae. One of the main objectives of this review is to stimulate an exploration of the mechanisms that link cellular quiescence to chronological aging of budding yeast. Yeast chronological aging is defined by the length of time during which a yeast cell remains viable after its growth and division are arrested, and it becomes quiescent. We propose a hypothesis on how caloric restriction can slow chronological aging of S. cerevisiae by altering the chronology and properties of quiescent cells. Our hypothesis posits that caloric restriction delays yeast chronological aging by targeting four different processes within quiescent cells.

scholarly journals Construction of model strain of yeast Saccharomyces cerevisiae with regulated expression of recombinant human alpha-synuclein

2021 ◽  
Vol 15 (3) ◽  
pp. 41-50
Author(s):  
N. V. Hrushanyk ◽  
◽  
Y. I. Fedorko ◽  
O. V. Stasyk ◽  
O. G. Stasyk ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Green Fluorescent Protein ◽  
Recombinant Protein ◽  
Recombinant Strain ◽  
Lipid Membrane ◽  
Fluorescent Protein ◽  
Intracellular Localization ◽  
Alpha Synuclein ◽  
Yeast Cells ◽  
Green Fluorescent

Background. Improper folding and accumulation of a-synuclein aggregates are among the causes of Parkinson’s disease. The most important factor influencing the process of α-synuclein aggregation is the level of this protein in neurons which depends on the balance between its synthesis, degradation and secretion. Under certain conditions, when α-synuclein is synthesized at a high level, monomers of this protein can aggregate on the lipid membrane, which leads to the formation of amyloids, fibrils and protofibrils unable to perform their physiological functions. Since it is virtually impossible to study the properties of α-synuclein in vivo, researchers are actively using model biological systems (single-celled microorganisms, human cell lines, animal models etc.). The aim of this study was to construct a recombinant strain of Saccharomyces cerevisiae with controlled expression of human α-synuclein to study the regulation and properties of this protein and for screening for new low molecular weight chemi­cal compounds which can induce α-synuclein aggregation and/or degradation. Materials and methods. A recombinant strain of S. cerevisiae with controlled expression of α-synuclein conjugated to a green fluorescent protein was isolated. Western blotting with specific anti-α-synuclein antibodies was used to detect recombinant α-synuclein in yeast cells. Intracellular localization of heterologous chimeric green fluorescent protein conjugated to α-synuclein was also examined by fluorescence microscopy. Results. To construct a recombinant strain of S. cerevisiae, the coding sequence of the human wild-type α-synuclein gene was expressed under the regulated promoter of the ScMET25 gene. Analysis of the effect of different concentrations of exogenous methionine as a factor regulating the expression of the ScMET25 promoter on the content of recombinant protein showed that the expression of the human α-synuclein gene in S. cerevisiae is repressed in the presence of methionine at a concentration of 10 mg/L and higher. During long-term cultivation of yeast cells, this effect decreased due to the depletion of methionine in the growth medium. As a result, recombinant protein synthesis was restored, and α-synuclein content in such cells approached that of cells grown in a medium with a low concentration of (5 mg/L), or without methionine. It was also found that overproduction of recombinant α-synuclein in S. cerevisiae cells had virtually no effect on culture growth, indicating the absence or a very weak toxic effect of human α-synuclein on yeast physiology. Conclusions. The obtained data indicate a concentration-dependent effect of methionine on the level of recombinant α-synuclein synthesis in S. cerevisiae yeast cells. Such controlled expression of the studied protein can be used to screen for compounds capable of promoting dose-dependent aggregation or degradation of α-synuclein in yeast cells and potentially in human cells as well.

Heterogeneity of Size and Distribution of Intramembrane Particles in the Plasma Membrane of Yeast

1977 ◽  
Vol 35 ◽  
pp. 596-597
Author(s):  
E. Keyhani
Keyword(s):  
Plasma Membrane ◽  
Candida Utilis ◽  
Synthetic Medium ◽  
Freeze Fracture ◽  
Translational Diffusion ◽  
Yeast Cells ◽  
Distilled Water ◽  
Intramembrane Particles ◽  
The Matrix ◽  
Water Cell

The matrix of biological membranes consists of a lipid bilayer into which proteins or protein aggregates are intercalated. Freeze-fracture techni- ques permit these proteins, perhaps in association with lipids, to be visualized in the hydrophobic regions of the membrane. Thus, numerous intramembrane particles (IMP) have been found on the fracture faces of membranes from a wide variety of cells (1-3). A recognized property of IMP is their tendency to form aggregates in response to changes in experi- mental conditions (4,5), perhaps as a result of translational diffusion through the viscous plane of the membrane. The purpose of this communica- tion is to describe the distribution and size of IMP in the plasma membrane of yeast (Candida utilis).Yeast cells (ATCC 8205) were grown in synthetic medium (6), and then harvested after 16 hours of culture, and washed twice in distilled water. Cell pellets were suspended in growth medium supplemented with 30% glycerol and incubated for 30 minutes at 0°C, centrifuged, and prepared for freeze-fracture, as described earlier (2,3).

Ultrathin frozen sections of yeast without aldehyde prefixation

1978 ◽  
Vol 36 (2) ◽  
pp. 58-59
Author(s):  
K. J. Böhm ◽  
a. E. Unger
Keyword(s):  
Aqueous Solutions ◽  
Biological Material ◽  
Yeast Cells ◽  
Frozen Sections ◽  
Good Preservation ◽  
Ultrathin Frozen Sections

During the last years it was shown that also by means of cryo-ultra-microtomy a good preservation of substructural details of biological material was possible. However the specimen generally was prefixed in these cases with aldehydes.Preparing ultrathin frozen sections of chemically non-prefixed material commonly was linked up to considerable technical and manual expense and the results were not always satisfying. Furthermore, it seems to be impossible to carry out cytochemical investigations by means of treating sections of unfixed biological material with aqueous solutions.We therefore tried to overcome these difficulties by preparing yeast cells (S. cerevisiae) in the following manner:

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