Ricardo
Ribeiro
...
DP_AEM student
Institute for Bioengineering and Biosciences (IBB)
Doctoral Program in Biotechnology and Biosciences (Técnico)
2017-2021
Prof.Dr. Isabel Sá-Correia
Ricardo
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Phd Thesis

Yeast response and tolerance to stress at the level of the cell envelope

The carboxylic weak acid acetic acid is a major inhibitory compound in industrial

bioprocesses and a widely used preservative in foods and beverages to control

microbial growth.

Among the mechanisms that have been proposed to underlie Saccharomyces

cerevisiae adaptation and tolerance to acetic acid is the remodeling of the cell

envelope. The major goal of this project is to achieve a coordinated and

comprehensive view on the time-course of the alterations occurring at the level of the

cell envelope, with focus on the cell wall, in a yeast cell population during adaptation to

sudden exposure to a sub-lethal stress induced by acetic acid. The alterations at the

molecular and biophysical level occurring at the level of yeast cell wall architecture

during adaptation will be assessed based on cell wall susceptibility to lyticase activity

and on cell wall nanomechanical properties by Atomic Force Microscopy. The

transcriptional activation of genes involved in cell wall synthesis and remodeling will be

assessed by qRT-PCR and the content of cell wall polysaccharides by fluorescence

microscopy. In addition, this PhD program has as goal to examine the hypothesized

influence of plasma membrane transporter Pdr18, a determinant of yeast acetic acid

tolerance, in cell wall homeostasis during acetic acid stress, in particular its influence in

the molecular and biophysical alterations occurring at the level of the cell wall.

Furthermore, this project also aims to obtain mechanistic insights into the mechanisms

underlying yeast response and resistance to acetic acid, by characterization of the

structure of Haa1 transcription factor, the key regulator of the of yeast resistance to

acetic acid, which are so far unknown. Overexpression and purification of Haa1 of

Saccharomyces cerevisiae and of the highly acetic acid resistant species

Zygosaccharomyces bailii will be used for X-ray structural analysis of Haa1 proteins

and their complexes with the Haa1- responsive element.

Publication and Meetings

Ribeiro, R.A., Vitorino, M.V., Godinho, C.P. et al. Yeast adaptive response to acetic acid stress involves structural alterations and increased stiffness of the cell wall. Sci Rep 11, 12652 (2021). https://doi.org/10.1038/s41598-021-92069-3

2017 - DP_AEM Workshop  

2018 -3rd Joint BIOTECnico and AEM PhD Programs Workshop

2020 - DP_AEM Students’seminars

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June 2019 - 7th Conference on Phisiology of Yeast and Filamentous Fungi ( 7th PYFF) - “Yeast response and tolerance to acetic acid: focus on the cell envelope”, - oral presentation

 

5th-7th December 2019 - Congress of Microbiology and Biotechnology 2019 (Microbiotec’19) “Yeast response and tolerance to acetic acid: focus on the cell envelope”, - oral presentation

 

23th-26th December 2021 - Congress of Microbiology and Biotechnology 2021 (Microbiotec’21) - "Response to acetic acid in yeast: focus on cell wall remodeling", - Short oral presentation 

 

9-10 April 2019, PhD Open Days - fifth edition - "Yeast response to acetic acid: focus on cell envelope properties, assessed by Atomic Force Microscopy" - poster presentation


Publication

Ribeiro, R.A., Vitorino, M.V., Godinho, C.P. et al. Yeast adaptive response to acetic acid stress involves structural alterations and increased stiffness of the cell wall. Sci Rep 11, 12652 (2021). https://doi.org/10.1038/s41598-021-92069-3