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On September 30th, George Kapetanakis (on the right in the picture) publicly presented his PhD work and successfully received his diploma. His research dealt with the poorly known process of amino-acid excretion by yeast cells. He characterized two novel amino-acid exporters and showed that these proteins importantly contribute to cross-feeding by yeast of co-cultivated lactic acid bacteria which cannot grow without an external supply of amino acids. G Kapetanakis also showed that the same proteins mediate excretion of amino acids and cross-feeding of lactic acid bacteria by the Ethanol Red yeast strain used in industrial bioethanol production. This observation is important since contamination of fermenters by lactic acid bacteria is a major issue in bioethanol production. We thus proposed in a novel patent of ULB that the utilization of yeast mutants lacking specific amino-acid exporters reduce the risk of contaminations of bioethanol production tanks by lactic acid bacteria. George Kapetanakis has now been hired as Research and Innovation Scientist in the young Paleo startup (see previous post). Congratulations and thanks to George for his scientific achievements and their potential industrial applications, and good luck with the new job in Paleo!
The startup company Paleo exploits yeast to produce GMO-free, heme proteins of beef and other animals for plant-based meat alternatives, with the ultimate goal of making food production more ethical and sustainable. Paleo recently moved into the lab space and offices next to our lab in the IBMM (Institute of Molecular Biology and Medicine). We established excellent contacts with the Paleo team members and we look forward to collaborate with them. Welcome to Paleo and great success in the future!
Nadia Guarini, Luis Sousa, Christopher Dereppe and Bruno André participated to the Interuniversity PhD student day organized in Namur last September 9th. As most other PhD students who attended this event, Nadia, Luis and Christopher presented a flash talk and a poster. This PhD student day, which was cancelled the last two previous years, was a big success.
Nadia Guarini attended the Yeast Genetics meeting 2022 organized at University of California in Los Angeles (August 17–21). She presented a “flash-talk” and a poster about her work on the role of the yeast H+-ATPase (Pma1) in control of TORC1 in yeast. This conference, the first edition of which was organized 40 years ago, is the “premier meeting for students, postdoctoral scholars, research staff, and principal investigators studying various aspects of eukaryotic biology in yeast, a major experimental model for understanding human cell biology and mechanisms of human disease“.
B. André participated to the EMBO workshop “Membrane transporters as essential elements of cellular function and homeostasis” organized in Chania (Crete) on August 23-27. He was invited to give a presentation entitled “Interlinks between transporters and TORC1”. This wonderful workshop organized by Pr. G. Diallinas gathered many experts studying the 3D structure, function, regulation, links with diseases and other aspects of membrane transporters from various organisms.
On May 13, the group of Isabelle Georis and our laboratory co-organized the “Yeasterday” meeting in Brussels. This annual meeting gathers scientists from the Benelux who use yeast as a model system or a tool in their research. The oral presentations given by young colleagues (PhD students and postdocs) were of top quality. Luis Sousa from our lab had the opportunity to present his work about amino acid excretion by yeast cells. The final plenary lecture was presented by Dr. Isabelle Sagot (CNRS, IBGC, Bordeaux) about the “The cell biology of quiescent yeast”. We thank all speakers, attendees and sponsors (Paelo, Syngulon FNRS, Rocc, aquilabiolabs) for this exciting science sharing day !
 We are pleased to announce the publication in iScience of an article entitled “Plasma membrane H+-ATPases promote TORC1 activation in plant suspension cells“. This study was carried out by Dr. Cecilia Primo in tight collaboration with the group of Pr. François Chaumont (UCLouvain, Belgium). The article reports that similar to what we have shown in yeast (Saliba et al. 2018, 2021), plasma membrane H+-ATPases in plant cells play an important role in regulation of TORC1 (Target Of Rapamycin Complex 1), the kinase complex coordinating cell growth and metabolism. This study opens the perspectives of better understanding the well-established role of these H+ pumps in regulation of plant cell growth and exploiting this new knowledge in biotechnological processes.
Good news for the end of this year! Christopher Dereppe was informed by the FNRS that he’s among the laureates of the last competition for FRIA fellowships. Christopher obtained a master diploma in Biochemistry and Molecular and Cellular Biology in 2021 at ULB. He did his master thesis work in our lab where he investigated a novel pathway of TORC1 activation in yeast. He will now further investigate the signals and molecular mechanisms of this pathway. Congratulations to him !
George Kapetanakis and Bruno André attended the 71st National Conference of the Hellenic Society of Biochemistry & Molecular Biology. George K. gave a presentation on his recent work on amino acid export proteins and Bruno A. was invited to give a conference on TOR regulation in yeast.
Yeast cells can excrete metabolites, in particular amino acids. These compounds can then be used by other microorganisms which can establish mutualistic interaction with yeast. How do yeast cells excrete amino acids remains poorly known. Thanks to a fruitful collaboration with the group of Dr. Isabelle Georis (Labiris, Anderlecht), George Kapetanakis (PhD student supported by FRIA) characterized Aqr1, Qdr2 and Qdr3 as three amino-acid exporters. Importantly, a yeast triple mutant lacking these proteins displays reduced capability of cross-feeding lactic acid bacteria, which cannot grow without an external amino acid supply. This study entitled “Overlapping Roles of Yeast Transporters Aqr1, Qdr2, and Qdr3 in Amino Acid Excretion and Cross-Feeding of Lactic Acid Bacteria” has just been published in the journal “Frontiers in Microbiology”.
Lactic acid bacteria are frequently found as contaminants during biofuel ethanol fermentation processes, and these infections represent a pervasive problem for many companies. As the yeast mutant described in our study provides a potential solution to this industrial problem, ULB has patented it. Furthermore, a proof of concept (POC) project supported by the Région wallonne now allows us to assess the efficiency of our invention under industrial conditions in collaboration with the start-up company Syngulon.
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