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Yeast cell death can occur during wine alcoholic fermentation and lead to sluggish or stuck fermentations. The mechanisms underlying cell death during yeast starvation in alcoholic fermentations remain unclear. In this work we addressed yeast cell death using conceptual framework from ageing studies showing that yeast resistance to starvation can be influenced by the nature of the nutrient limiting cell growth. We examined cell death occurrence considering yeast cells ability to elicit an appropriate response to a set of nutrient limitations. We show that several micronutrients limitations (oleic acid, ergosterol, pantothenic acid and nicotinic acid) trigger cell death in a nitrogen-dependent manner. We provide evidence that the nitrogen Tor/Sch9 signaling pathway is involved in triggering cell death. In such conditions, yeast cells fail to acquire stress resistance given a restriction at a post-transcriptional level. We have examined the ability of different nitrogen sources to trigger cell death and show that they impact differentially on cell death and that NH4 + had a strong death inducing capacity. Finally, the QTLs approaches allowed the mapping of a set of loci controlling cell death under oleic acid and pantothenic acid starvation consistent with a multigenic control.

The mechanisms involved in the establishment of the resistance of the medium-chain fatty acids (octanoic and decanoic acids) are characterized. The comparison of the transcriptional responses to the responses caused by other lipophilic compound has shown the role of several transcription factors.

Abstract Background Wine aroma results from the combination of numerous volatile compounds, some produced by yeast and others produced in the grapes and further metabolized by yeast. However, little is known about the consequences of the genetic variation of yeast on the production of these volatile metabolites, or on the metabolic pathways involved in the metabolism of grape compounds. As a tool to decipher how wine aroma develops, we analyzed, under two experimental conditions, the production of 44 compounds by a population of 30 segregants from a cross between a laboratory strain and an industrial strain genotyped at high density. Results We detected eight genomic regions explaining the diversity concerning 15 compounds, some produced de novo by yeast, such as nerolidol, ethyl esters and phenyl ethanol, and others derived from grape compounds such as citronellol, and cis-rose oxide. In three of these eight regions, we identified genes involved in the phenotype. Hemizygote comparison allowed the attribution of differences in the production of nerolidol and 2-phenyl ethanol to the PDR8 and ABZ1 genes, respectively. Deletion of a PLB2 gene confirmed its involvement in the production of ethyl esters. A comparison of allelic variants of PDR8 and ABZ1 in a set of available sequences revealed that both genes present a higher than expected number of non-synonymous mutations indicating possible balancing selection. Conclusions This study illustrates the value of QTL analysis for the analysis of metabolic traits, and in particular the production of wine aromas. It also identifies the particular role of the PDR8 gene in the production of farnesyldiphosphate derivatives, of ABZ1 in the production of numerous compounds and of PLB2 in ethyl ester synthesis. This work also provides a basis for elucidating the metabolism of various grape compounds, such as citronellol and cis-rose oxide.

Despite the high energetic cost of the reduction of sulfate to H 2 S, required for the synthesis of sulfur-containing amino acids, some wine Saccharomyces cerevisiae strains have been reported to produce excessive amounts of H 2 S during alcoholic fermentation, which is detrimental to wine quality. Surprisingly, in the presence of sulfite, used as a preservative, wine strains produce more H 2 S than wild (oak) or wine velum (flor) isolates during fermentation. Since copper resistance caused by the amplification of the sulfur rich protein Cup1p is a specific adaptation trait of wine strains, we analyzed the link between copper resistance mechanism, sulfur metabolism and H 2 S production. We show that a higher content of copper in the must increases the production of H 2 S, and that SO 2 increases the resistance to copper. Using a set of 51 strains we observed a positive and then negative relation between the number of copies of CUP1 and H 2 S production during fermentation. This complex pattern could be mimicked using a multicopy plasmid carrying CUP1, confirming the relation between copper resistance and H 2 S production. The massive use of copper for vine sanitary management has led to the selection of resistant strains at the cost of a metabolic tradeoff: the overproduction of H 2 S, resulting in a decrease in wine quality., (© 2024. The Author(s).)

Saccharomyces cerevisiae requirement for reduced sulfur to synthesize methionine and cysteine during alcoholic fermentation, is mainly fulfilled through the sulfur assimilation pathway. Saccharomyces cerevisiae reduces sulfate into sulfur dioxide (SO2) and sulfide (H2S), whose overproduction is a major issue in winemaking, due to its negative impact on wine aroma. The amount of H2S produced is highly strain-specific and also depends on SO2 concentration, often added to grape must. Applying a bulk segregant analysis to a 96-strain-progeny derived from two strains with different abilities to produce H2S, and comparing allelic frequencies along the genome of pools of segregants producing contrasting H2S quantities, we identified two causative regions involved in H2S production in the presence of SO2. A functional genetic analysis allowed the identification of variants in four genes able to impact H2S formation, viz; ZWF1, ZRT2, SNR2, and YLR125W, and involved in functions and pathways not associated with sulfur metabolism until now. These data point out that, in wine fermentation conditions, redox status, and zinc homeostasis are linked to H2S formation while providing new insights into the regulation of H2S production, and a new vision of the interplay between the sulfur assimilation pathway and cell metabolism., (© The Author(s) 2023. Published by Oxford University Press on behalf of FEMS.)

The fresh mushroom off-flavor (FMOff) is due to several C8 compounds such as 1-octen-3-one, 1-octen-3-ol and 1-hydroxyoctan-3-one, among others. Recently, glycosidic precursors of some FMOff compounds have been identified in grape musts, but the evolution of such compounds during alcoholic fermentation (AF) remains poorly studied. Therefore, the aim of this work was to monitor both FMOff glycosidic precursors and volatile compounds during AF by comparing healthy and Crustomyces subabruptus -contaminated musts. For the first time, glycosidic analysis revealed the presence of 1-hydroxyoctan-3-one glycosides in the laboratory-contaminated musts, together with other FMOff glycosidic fractions already described in the literature. During AF, the FMOff glycosidic fraction decreased, even more in the case of 1-hydroxyoctan-3-one precursors. For the volatile FMOff compounds, their evolutions were both compound- and matrix-dependent except for 1-hydroxyoctan-3-one, which seemed to reach an identical threshold concentration in wine regardless of its initial level in contaminated musts.

Competing Interests: We declare no competing interests.

An organoleptic defect, termed fresh mushroom off-flavor and mainly caused by the C8 compounds 1-octen-3-one, 3-octanol and 1-octen-3-ol, has been identified in wines and spirits since the 2000s. The aim of this work was to identify the presence of glycosidic precursors of these C8 compounds and to evaluate the influence of different molds on the glycosylated fractions of three grape varieties. Must samples contaminated by molds (gray rot, powdery mildew and Crustomyces subabruptus ) and three levels of attack severity (from healthy to 10-15%) were studied. After a β -glycosidase treatment on Meunier and Pinot noir musts contaminated by Crustomyces subabruptus , 1-octen-3-one, 1-octen-3-ol and 3-octanol were identified by GC-MS, proving the existence of glycosidic fractions in the musts. A Pinot noir must contaminated by Crustomyces subabruptus displayed a 230% increase in the glycosylated fraction responsible for 1-octen-3-one in comparison with an uncontaminated sample. Powdery mildew did not appear to affect the levels of the studied glycosidic fractions in Chardonnay musts. Gray rot on Meunier and Pinot noir musts had opposite effects depending on glycoside type, decreasing the 1-octen-3-one fraction and increasing the 1-octen-3-ol fraction.

Indigenous Peoples have resiliently weathered continued assaults on their sovereignty and rights throughout colonialism and its continuing effects. Indigenous Peoples' sovereignty has been strained by the increasing effects of global environmental change within their territories, including climate change and pollution, and by threats and impositions against their land and water rights. This continuing strain against sovereignty has prompted a call to action to conceptualise the determinants of planetary health from a perspective that embodied Indigenous-specific methods of knowledge gathering from around the globe. A group of Indigenous scholars, practitioners, land and water defenders, respected Elders, and knowledge-holders came together to define the determinants of planetary health from an Indigenous perspective. Three overarching levels of interconnected determinants, in addition to ten individual-level determinants, were identified as being integral to the health and sustainability of the planet, Mother Earth., Competing Interests: Declaration of interests We declare no competing interests., (Copyright © 2022 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY-NC-ND 4.0 license. Published by Elsevier Ltd.. All rights reserved.)

A range of global environmental changes are contributing to an increasing global burden of disease. Since human health and well-being are intimately associated with the health of our planet, healthcare providers will not only be charged with caring for this expanding disease burden but will also need to become more environmentally sustainable in their professional practice. There is thus an urgent need in the health professions education community to prioritize environmentally sustainable healthcare practice, which must include and prioritize Indigenous voices and Indigenous knowledge systems. Critical global dialogue on the significance of Indigenous knowledge systems in educating health professionals for a sustainable future will be required if we are ready to ensure the generations that follow us are able to live healthy lives. Indigenous ways of 'being' in the world, which emphasize the importance of interconnection and reciprocal stewardship with everything in the natural world, are essential for advancing education for sustainable healthcare and overall well-being. Given the colonial legacy however, Indigenous people, despite their essential knowledge systems and abilities, still face many barriers accessing safe decolonizing spaces and presence in health professions education, which needs to be addressed.

Background: Despite the documented continued use of traditional healing methods, modalities and its associated practitioners by Indigenous groups across North America, it is presumed that widespread knowledge is elusive amongst most Western trained health professionals and systems. This despite that the approximately 7.5 million Indigenous peoples who currently reside in Canada and the United States (US) are most often served by Western systems of medicine. A state of the literature is currently needed in this area to provide an accessible resource tool for medical practitioners, scholars, and communities to better understand Indigenous traditional medicine in the context of current clinical care delivery and future policy making., Methods: A systematic search of multiple databases was performed utilizing an established scoping review framework. A consequent title and abstract review of articles published on traditional Indigenous medicine in the North American context was completed., Findings: Of the 4,277 published studies identified, 249 met the inclusion criteria divided into the following five categorical themes: General traditional medicine, integration of traditional and Western medicine systems, ceremonial practice for healing, usage of traditional medicine, and traditional healer perspectives., Conclusions: This scoping review was an attempt to catalogue the wide array of published research in the peer-reviewed and online grey literature on traditional Indigenous medicine in North America in order to provide an accessible database for medical practitioners, scholars, and communities to better inform practice, policymaking, and research in Indigenous communities., Competing Interests: The authors have declared that no competing interests exist.

In this commentary, we argue that Indigenous patients in the Northwest Territories (NWT) have a right to access traditional medicine and related practitioners as a part of the continuum of medical care. Indigenous people make up over half of the NWT population, spread over vast geographic areas with representation from First Nations, Inuit and Métis (FNIM) people. Ensuring barrier-free access to traditional medicine and providers in a culturally respectful environment is a challenge that requires structural transformation in the territorial health system. The ongoing transmission of knowledge about Indigenous traditional medicine in Northern Canada and the collective survival of Northern peoples is a testament to the applicability of traditional medicines in a self-determined wellness system. Through a discussion of the barriers to policy development and implementation, this commentary aims to elevate Indigenous perspectives and offer recommendations for integrating traditional medicines into Northern health systems.

Nitrogen composition of the grape must has an impact on yeast growth and fermentation kinetics as well as on the organoleptic properties of the final product. In some technological processes, such as white wine/rosé winemaking, the yeast-assimilable nitrogen content is sometimes insufficient to cover yeast requirements, which can lead to slow or sluggish fermentations. Growth is nevertheless quickly restored upon relief from nutrient starvation, e.g. through the addition of ammonium nitrogen, allowing fermentation completion. The aim of this study was to determine how nitrogen repletion affected the transcriptional response of a Saccharomyces cerevisiae wine yeast strain, in particular within the first hour after nitrogen addition. We found almost 4800 genes induced or repressed, sometimes within minutes after nutrient changes. Some of these responses to nitrogen depended on the TOR pathway, which controls positively ribosomal protein genes, amino acid and purine biosynthesis or amino acid permease genes and negatively stress-response genes, and genes related to the retrograde response (RTG) specific to the tricarboxylic acid (TCA) cycle and nitrogen catabolite repression (NCR). Some unexpected transcriptional responses concerned all the glycolytic genes, carbohydrate metabolism and TCA cycle-related genes that were down-regulated, as well as genes from the lipid metabolism., Competing Interests: The authors have declared that no competing interests exist.

During winemaking Saccharomyces cerevisiae strains are exposed continuously to environmental changes and this microorganism responds modifying its transcriptional profile. Yeast flocculation is considered a social trait that allows the cells to escape from hostile conditions by sedimentation. This behaviour is based on the self-interaction of flocculins, proteins encoded by FLO family genes. These are considered responsible of the facultative-helping type cooperation and were designed as green-beard genes. In order to understand the role of flocculation to stress response, the genome wide expression analysis of a wine flocculent S. cerevisiae F6789A strain and its FLO5 deleted strain (F6789A-Δflo5) were determined, using DNA microarray technology. Results highlighted that F6789A strain showed a shorter lag phase in winemaking condition. The comparison of transcriptomic profiles underlined that, while F6789A-Δflo5 strain seemed engaged in the re-organization of the cell wall and in finding different adhesion ways, F6789A strain presented an up-regulation of genes involved in stress response and higher alcohol production., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Nitrogen replenishment of nitrogen-starved yeast cells resulted in substantial transcriptome changes. There was an unexplained rapid, transient down-regulation of glycolytic genes. This unexpected result prompted us to search for the factors controlling these changes, among which is the possible involvement of different nutrient-sensing pathways such as the TORC1 and cAMP/PKA pathways. To that end, the effects of various gene deletions or chemical blocking agents were tested by investigating the expression of PGK1 , one of the glycolytic genes most affected after nitrogen replenishment. We report here that several factors affected glycolytic mRNA stability, among which were glucose sensing, protein elongation, nitrogen metabolism, and TOR signaling. Ammonium sensing was not involved in the response, but ammonium metabolism was required. Thus, our results suggest that, in the presence of glucose, carbon/nitrogen cross-talk is likely involved in the response to nitrogen upshift. Our data suggest that posttranscriptional control of glycolytic gene expression may be an important response to nitrogen replenishment., (© 2018 Tesnière et al. This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).)

Background: Prostate Cancer (PCa) is the second most prevalent cancer among U.S. males. In recent decades many men with low risk PCa have been over diagnosed and over treated. Given significant co-morbidities associated with definitive treatments, maximizing patient quality of life while recognizing early signs of aggressive disease is essential. There remains a need to better stratify newly diagnosed men according to the risk of disease progression, identifying, with high sensitivity and specificity, candidates for active surveillance versus intervention therapy. The objective of this study was to select fluorescence in situ hybridization (FISH) panels that differentiate non-progressive from progressive disease in patients with low and intermediate risk PCa., Methods: We performed a retrospective case-control study to evaluate FISH biomarkers on specimens from PCa patients with clinically localised disease (T1c-T2c) enrolled in Watchful waiting (WW)/Active Surveillance (AS). The patients were classified into cases (progressed to clinical intervention within 10 years), and controls (did not progress in 10 years). Receiver Operating Characteristic (ROC) curve analysis was performed to identify the best 3-5 probe combinations. FISH parameters were then combined with the clinical parameters ─ National Comprehensive Cancer Network (NNCN) risk categories ─ in the logistic regression model., Results: Seven combinations of FISH parameters with the highest sensitivity and specificity for discriminating cases from controls were selected based on the ROC curve analysis. In the logistic regression model, these combinations contributed significantly to the prediction of PCa outcome. The combination of NCCN risk categories and FISH was additive to the clinical parameters or FISH alone in the final model, with odds ratios of 5.1 to 7.0 for the likelihood of the FISH-positive patients in the intended population to develop disease progression, as compared to the FISH-negative group., Conclusions: Combinations of FISH parameters discriminating progressive from non-progressive PCa were selected based on ROC curve analysis. The combination of clinical parameters and FISH outperformed clinical parameters alone, and was complimentary to clinical parameters in the final model, demonstrating potential utility of multi-colour FISH panels as an auxiliary tool for PCa risk stratification. Further studies with larger cohorts are planned to confirm these findings.

Yeast cell death can occur during wine alcoholic fermentation. It is generally considered to result from ethanol stress that impacts membrane integrity. This cell death mainly occurs when grape musts processing reduces lipid availability, resulting in weaker membrane resistance to ethanol. However the mechanisms underlying cell death in these conditions remain unclear. We examined cell death occurrence considering yeast cells ability to elicit an appropriate response to a given nutrient limitation and thus survive starvation. We show here that a set of micronutrients (oleic acid, ergosterol, pantothenic acid and nicotinic acid) in low, growth-restricting concentrations trigger cell death in alcoholic fermentation when nitrogen level is high. We provide evidence that nitrogen signaling is involved in cell death and that either SCH9 deletion or Tor inhibition prevent cell death in several types of micronutrient limitation. Under such limitations, yeast cells fail to acquire any stress resistance and are unable to store glycogen. Unexpectedly, transcriptome analyses did not reveal any major changes in stress genes expression, suggesting that post-transcriptional events critical for stress response were not triggered by micronutrient starvation. Our data point to the fact that yeast cell death results from yeast inability to trigger an appropriate stress response under some conditions of nutrient limitations most likely not encountered by yeast in the wild. Our conclusions provide a novel frame for considering both cell death and the management of nutrients during alcoholic fermentation.

Flocculation is an important feature for yeast survival in adverse conditions. The natural diversity of flocculating genes in Saccharomyces cerevisiae can also be exploited in several biotechnological applications. Flocculation is mainly regulated by the expression of genes belonging to the FLO family. These genes have a similar function, but their specific contribution to flocculation ability is still unclear. In this study, the distribution of FLO1, FLO5 and FLO8 genes in four S. cerevisiae wine strains was investigated. Subsequently, both FLO1 and FLO5 genes were separately deleted in a flocculent S. cerevisiae wine strain. After gene disruption, flocculation ability and agar adhesion were evaluated. FLO1 and FLO5 genes inheritance was also monitored. All strains presented different lengths for FLO1 and FLO5 genes. Results confirm that in S. cerevisiae strain F6789, the FLO5 gene drives flocculation and influences adhesive properties. Flocculation ability monitoring after a cross with a non-flocculent strain revealed that FLO5 is the gene responsible for flocculation development.

Nitrogen is an important nutrient in alcoholic fermentation because its starvation affects both fermentation kinetics and the formation of yeast metabolites. In most alcoholic fermentations, yeasts have to ferment in nitrogen-starved conditions, which requires modifications of cell functions to maintain a high sugar flux and enable cell survival for long periods in stressful conditions. In this review, we present an overview of our current understanding of the responses of the wine yeast Saccharomyces cerevisiae to variations of nitrogen availability. Adaptation to nitrogen starvation involves changes in the activity of signaling pathways such as target of rapamycin (TOR) and nitrogen catabolite repression (NCR), which are important for the remodeling of gene expression and the establishment of stress responses. Upon starvation, protein degradation pathways involving autophagy and the proteasome play a major role in nitrogen recycling and the adjustment of cellular activity. Recent progress in the understanding of the role of these mechanisms should enable advances in fermentation management and the design of novel targets for the selection or improvement of yeast strains.

Background: Wine yeasts can produce undesirable sulfur compounds during alcoholic fermentation, such as SO2 and H2S, in variable amounts depending mostly on the yeast strain but also on the conditions. However, although sulfur metabolism has been widely studied, some of the genetic determinants of differences in sulfite and/or sulfide production between wine yeast strains remain to be identified. In this study, we used an integrated approach to decipher the genetic determinants of variation in the production of undesirable sulfur compounds., Results: We examined the kinetics of SO2 production by two parental strains, one high and one low sulfite producer. These strains displayed similar production profiles but only the high-sulfite producer strain continued to produce SO2 in the stationary phase. Transcriptomic analysis revealed that the low-sulfite producer strain overexpressed genes of the sulfur assimilation pathway, which is the mark of a lower flux through the pathway consistent with a lower intracellular concentration in cysteine. A QTL mapping strategy then enabled us to identify MET2 and SKP2 as the genes responsible for these phenotypic differences between strains and we identified new variants of these genes in the low-sulfite producer strain. MET2 influences the availability of a metabolic intermediate, O-acetylhomoserine, whereas SKP2 affects the activity of a key enzyme of the sulfur assimilation branch of the pathway, the APS kinase, encoded by MET14. Furthermore, these genes also affected the production of propanol and acetaldehyde. These pleiotropic effects are probably linked to the influence of these genes on interconnected pathways and to the chemical reactivity of sulfite with other metabolites., Conclusions: This study provides new insight into the regulation of sulfur metabolism in wine yeasts and identifies variants of MET2 and SKP2 genes, that control the activity of both branches of the sulfur amino acid synthesis pathway and modulate sulfite/sulfide production and other related phenotypes. These results provide novel targets for the improvement of wine yeast strains.

Background: Thiamine availability is involved in glycolytic flux and fermentation efficiency. A deficiency of this vitamin may be responsible for sluggish fermentations in wine making. Therefore, both thiamine uptake and de novo synthesis could have key roles in fermentation processes. Thiamine biosynthesis is regulated in response to thiamine availability and is coordinated by the thiamine sensor Thi3p, which activates Pdc2p and Thi2p. We used a genetic approach to identify quantitative trait loci (QTLs) in wine yeast and we discovered that a set of thiamine genes displayed expression-QTL on a common locus, which contains the thiamine regulator THI3., Results: We deciphered here the source of these regulatory variations of the THI and PDC genes. We showed that alteration of THI3 results in reduced expression of the genes involved in thiamine biosynthesis (THI11/12/13 and THI74) and increased expression of the pyruvate decarboxylase gene PDC1. Functional analysis of the allelic effect of THI3 confirmed the control of the THI and PDC1 genes. We observed, however, only a small effect of the THI3 on fermentation kinetics. We demonstrated that the expression levels of several THI genes are correlated with fermentation rate, suggesting that decarboxylation activity could drive gene expression through a modulation of thiamine content. Our data also reveals a new role of Thi3p in the regulation of the main pyruvate decarboxylase gene, PDC1., Conclusions: This highlights a switch from PDC1 to PDC5 gene expression during thiamine deficiency, which may improve the thiamine affinity or conservation during the enzymatic reaction. In addition, we observed that the lab allele of THI3 and of the thiamin transporter THI7 have diverged from the original alleles, consistent with an adaptation of lab strains to rich media containing an excess of thiamine.