Xiaohuan Zhang, Jeroen G Nijland, Arnold J M Driessen
{"title":"Maltose accumulation induced cell death in Saccharomyces cerevisiae","authors":"Xiaohuan Zhang, Jeroen G Nijland, Arnold J M Driessen","doi":"10.1093/femsyr/foae012","DOIUrl":"https://doi.org/10.1093/femsyr/foae012","url":null,"abstract":"Pretreatment of lignocellulose yields a complex sugar mixture that potentially can be converted into bioethanol and other chemicals by engineered yeast. One approach to overcome competition between sugars for uptake and metabolism is the use of a consortium of specialist strains capable of efficient conversion of single sugars. Here we show that maltose inhibits cell growth of a xylose-fermenting specialist strain IMX730.1 that is unable to utilize glucose because of the deletion of all hexokinase genes. The growth inhibition cannot be attributed to a competition between maltose and xylose for uptake. The inhibition is enhanced in a strain lacking maltase enzymes (dMalX2) and completely eliminated when all maltose transporters are deleted. High-level accumulation of maltose in the dMalX2 strain is accompanied by a hypotonic-like transcriptional response, while cells are rescued from maltose-induced cell death by the inclusion of an extracellular osmolyte such as sorbitol. These data suggest that maltose-induced cell death is due to high levels of maltose uptake causing hypotonic-like stress conditions and can be prevented through engineering of the maltose transporters. Transporter engineering should be included in the development of stable microbial consortia for the efficient conversion of lignocellulosic feedstocks.","PeriodicalId":12290,"journal":{"name":"FEMS yeast research","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140600894","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Natural trait variation across Saccharomycotina species","authors":"Johnson J-T Wang, Jacob L Steenwyk, Rachel B Brem","doi":"10.1093/femsyr/foae002","DOIUrl":"https://doi.org/10.1093/femsyr/foae002","url":null,"abstract":"Among molecular biologists, the group of fungi called Saccharomycotina is famous for its yeasts. These yeasts in turn are famous for what they have in common—genetic, biochemical, and cell-biological characters that serve as models for plants and animals. But behind the apparent homogeneity of Saccharomycotina species lie a wealth of differences. In this review, we discuss traits that vary across the Saccharomycotina subphylum. We describe cases of bright pigmentation; a zoo of cell shapes; metabolic specialties; and species with unique rules of gene regulation. We discuss the genetics of this diversity and why it matters, including insights into basic evolutionary principles with relevance across Eukarya.","PeriodicalId":12290,"journal":{"name":"FEMS yeast research","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139462014","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Christina M Chavez, Marizeth Groenewald, Amanda B Hulfachor, Gideon Kpurubu, Rene Huerta, Chris Todd Hittinger, Antonis Rokas
{"title":"The cell morphological diversity of Saccharomycotina yeasts.","authors":"Christina M Chavez, Marizeth Groenewald, Amanda B Hulfachor, Gideon Kpurubu, Rene Huerta, Chris Todd Hittinger, Antonis Rokas","doi":"10.1093/femsyr/foad055","DOIUrl":"10.1093/femsyr/foad055","url":null,"abstract":"<p><p>The ∼1 200 known species in subphylum Saccharomycotina are a highly diverse clade of unicellular fungi. During its lifecycle, a typical yeast exhibits multiple cell types with various morphologies; these morphologies vary across Saccharomycotina species. Here, we synthesize the evolutionary dimensions of variation in cellular morphology of yeasts across the subphylum, focusing on variation in cell shape, cell size, type of budding, and filament production. Examination of 332 representative species across the subphylum revealed that the most common budding cell shapes are ovoid, spherical, and ellipsoidal, and that their average length and width is 5.6 µm and 3.6 µm, respectively. 58.4% of yeast species examined can produce filamentous cells, and 87.3% of species reproduce asexually by multilateral budding, which does not require utilization of cell polarity for mitosis. Interestingly, ∼1.8% of species examined have not been observed to produce budding cells, but rather only produce filaments of septate hyphae and/or pseudohyphae. 76.9% of yeast species examined have sexual cycle descriptions, with most producing one to four ascospores that are most commonly hat-shaped (37.4%). Systematic description of yeast cellular morphological diversity and reconstruction of its evolution promises to enrich our understanding of the evolutionary cell biology of this major fungal lineage.</p>","PeriodicalId":12290,"journal":{"name":"FEMS yeast research","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2024-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10804222/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139032217","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Regulation of copper uptake by the SWI/SNF chromatin remodeling complex in Candida albicans affects susceptibility to antifungal and oxidative stresses under hypoxia.","authors":"Inès Khemiri, Faiza Tebbji, Anaïs Burgain, Adnane Sellam","doi":"10.1093/femsyr/foae018","DOIUrl":"10.1093/femsyr/foae018","url":null,"abstract":"<p><p>Candida albicans is a human colonizer and also an opportunistic yeast occupying different niches that are mostly hypoxic. While hypoxia is the prevalent condition within the host, the machinery that integrates oxygen status to tune the fitness of fungal pathogens remains poorly characterized. Here, we uncovered that Snf5, a subunit of the chromatin remodeling complex SWI/SNF, is required to tolerate antifungal stress particularly under hypoxia. RNA-seq profiling of snf5 mutant exposed to amphotericin B and fluconazole under hypoxic conditions uncovered a signature that is reminiscent of copper (Cu) starvation. We found that under hypoxic and Cu-starved environments, Snf5 is critical for preserving Cu homeostasis and the transcriptional modulation of the Cu regulon. Furthermore, snf5 exhibits elevated levels of reactive oxygen species and an increased sensitivity to oxidative stress principally under hypoxia. Supplementing growth medium with Cu or increasing gene dosage of the Cu transporter CTR1 alleviated snf5 growth defect and attenuated reactive oxygen species levels in response to antifungal challenge. Genetic interaction analysis suggests that Snf5 and the bona fide Cu homeostasis regulator Mac1 function in separate pathways. Together, our data underlined a unique role of SWI/SNF complex as a potent regulator of Cu metabolism and antifungal stress under hypoxia.</p>","PeriodicalId":12290,"journal":{"name":"FEMS yeast research","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11160329/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140957155","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Increased production of isobutanol from xylose through metabolic engineering of Saccharomyces cerevisiae overexpressing transcription factor Znf1 and exogenous genes.","authors":"Pattanan Songdech, Chutikarn Butkinaree, Yodying Yingchutrakul, Peerada Promdonkoy, Weerawat Runguphan, Nitnipa Soontorngun","doi":"10.1093/femsyr/foae006","DOIUrl":"10.1093/femsyr/foae006","url":null,"abstract":"<p><p>Only trace amount of isobutanol is produced by the native Saccharomyces cerevisiae via degradation of amino acids. Despite several attempts using engineered yeast strains expressing exogenous genes, catabolite repression of glucose must be maintained together with high activity of downstream enzymes, involving iron-sulfur assimilation and isobutanol production. Here, we examined novel roles of nonfermentable carbon transcription factor Znf1 in isobutanol production during xylose utilization. RNA-seq analysis showed that Znf1 activates genes in valine biosynthesis, Ehrlich pathway and iron-sulfur assimilation while coupled deletion or downregulated expression of BUD21 further increased isobutanol biosynthesis from xylose. Overexpression of ZNF1 and xylose-reductase/dehydrogenase (XR-XDH) variants, a xylose-specific sugar transporter, xylulokinase, and enzymes of isobutanol pathway in the engineered S. cerevisiae pho13gre3Δ strain resulted in the superb ZNXISO strain, capable of producing high levels of isobutanol from xylose. The isobutanol titer of 14.809 ± 0.400 g/L was achieved, following addition of 0.05 g/L FeSO4.7H2O in 5 L bioreactor. It corresponded to 155.88 mg/g xylose consumed and + 264.75% improvement in isobutanol yield. This work highlights a new regulatory control of alternative carbon sources by Znf1 on various metabolic pathways. Importantly, we provide a foundational step toward more sustainable production of advanced biofuels from the second most abundant carbon source xylose.</p>","PeriodicalId":12290,"journal":{"name":"FEMS yeast research","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2024-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10878408/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139706498","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Philipp Ernst, Astrid Wirtz, Benedikt Wynands, Nick Wierckx
{"title":"Establishing an itaconic acid production process with Ustilago species on the low-cost substrate starch.","authors":"Philipp Ernst, Astrid Wirtz, Benedikt Wynands, Nick Wierckx","doi":"10.1093/femsyr/foae023","DOIUrl":"10.1093/femsyr/foae023","url":null,"abstract":"<p><p>Ustilago maydis and Ustilago cynodontis are natural producers of a broad range of valuable molecules including itaconate, malate, glycolipids, and triacylglycerols. Both Ustilago species are insensitive toward medium impurities, and have previously been engineered for efficient itaconate production and stabilized yeast-like growth. Due to these features, these strains were already successfully used for the production of itaconate from different alternative feedstocks such as molasses, thick juice, and crude glycerol. Here, we analyzed the amylolytic capabilities of Ustilago species for metabolization of starch, a highly abundant and low-cost polymeric carbohydrate widely utilized as a substrate in several biotechnological processes. Ustilago cynodontis was found to utilize gelatinized potato starch for both growth and itaconate production, confirming the presence of extracellular amylolytic enzymes in Ustilago species. Starch was rapidly degraded by U. cynodontis, even though no α-amylase was detected. Further experiments indicate that starch hydrolysis is caused by the synergistic action of glucoamylase and α-glucosidase enzymes. The enzymes showed a maximum activity of around 0.5 U ml-1 at the fifth day after inoculation, and also released glucose from additional substrates, highlighting potential broader applications. In contrast to U. cynodontis, U. maydis showed no growth on starch accompanied with no detectable amylolytic activity.</p>","PeriodicalId":12290,"journal":{"name":"FEMS yeast research","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2024-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11312366/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141747810","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tomas Strucko, Adrian-E Gadar-Lopez, Frederik B Frøhling, Emma T Frost, Esther F Iversen, Helen Olsson, Zofia D Jarczynska, Uffe H Mortensen
{"title":"Oligonucleotide-based CRISPR-Cas9 toolbox for efficient engineering of Komagataella phaffii.","authors":"Tomas Strucko, Adrian-E Gadar-Lopez, Frederik B Frøhling, Emma T Frost, Esther F Iversen, Helen Olsson, Zofia D Jarczynska, Uffe H Mortensen","doi":"10.1093/femsyr/foae026","DOIUrl":"10.1093/femsyr/foae026","url":null,"abstract":"<p><p>Komagataella phaffii (Pichia pastoris) is a methylotrophic yeast that is favored by industry and academia mainly for expression of heterologous proteins. However, its full potential as a host for bioproduction of valuable compounds cannot be fully exploited as genetic tools are lagging behind those that are available for baker's yeast. The emergence of CRISPR-Cas9 technology has significantly improved the efficiency of gene manipulations of K. phaffii, but improvements in gene-editing methods are desirable to further accelerate engineering of this yeast. In this study, we have developed a versatile vector-based CRISPR-Cas9 method and showed that it works efficiently at different genetic loci using linear DNA fragments with very short targeting sequences including single-stranded oligonucleotides. Notably, we performed site-specific point mutations and full gene deletions using short (90 nt) single-stranded oligonucleotides at very high efficiencies. Lastly, we present a strategy for transient inactivation of nonhomologous end-joining (NHEJ) pathway, where KU70 gene is disrupted by a visual marker (uidA gene). This system enables precise CRISPR-Cas9-based editing (including multiplexing) and facilitates simple reversion to NHEJ-proficient genotype. In conclusion, the tools presented in this study can be applied for easy and efficient engineering of K. phaffii strains and are compatible with high-throughput automated workflows.</p>","PeriodicalId":12290,"journal":{"name":"FEMS yeast research","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2024-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11364938/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142046550","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Santoshkumar R Gaikwad, Narayan S Punekar, Ejaj K Pathan
{"title":"Characterization of a novel 4-guanidinobutyrase from Candida parapsilosis.","authors":"Santoshkumar R Gaikwad, Narayan S Punekar, Ejaj K Pathan","doi":"10.1093/femsyr/foae003","DOIUrl":"10.1093/femsyr/foae003","url":null,"abstract":"<p><p>Enzymes of the ureohydrolase superfamily are specific in recognizing their substrates. While looking to broaden the substrate specificity of 4-guanidinobutyrase (GBase), we isolated a yeast, typed as Candida parapsilosis (NCIM 3689), that efficiently utilized both 4-guanidinobutyrate (GB) and 3-guanidinopropionate (GP) as a sole source of nitrogen. A putative GBase sequence was identified from its genome upon pBLAST query using the GBase sequence from Aspergillus niger (AnGBase). The C. parapsilosis GBase (CpGBase) ORF was PCR amplified, cloned, and sequenced. Further, the functional CpGBase protein expressed in Saccharomyces cerevisiae functioned as GBase and 3-guanidinopropionase (GPase). S. cerevisiae cannot grow on GB or GP. However, the transformants expressing CpGBase acquired the ability to utilize and grow on both GB and GP. The expressed CpGBase protein was enriched and analyzed for substrate saturation and product inhibition by γ-aminobutyric acid and β-alanine. In contrast to the well-characterized AnGBase, CpGBase from C. parapsilosis is a novel ureohydrolase and showed hyperbolic saturation for GB and GP with comparable efficiency (Vmax/KM values of 3.4 and 2.0, respectively). With the paucity of structural information and limited active site data available on ureohydrolases, CpGBase offers an excellent paradigm to explore this class of enzymes.</p>","PeriodicalId":12290,"journal":{"name":"FEMS yeast research","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10833137/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139502227","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Mutations of ribosomal protein genes induce overexpression of catalase in Saccharomyces cerevisiae.","authors":"Ching-Hsiang Hsu, Ching-Yu Liu, Kai-Yin Lo","doi":"10.1093/femsyr/foae005","DOIUrl":"10.1093/femsyr/foae005","url":null,"abstract":"<p><p>Ribosome assembly defects result in ribosomopathies, primarily caused by inadequate protein synthesis and induced oxidative stress. This study aimed to investigate the link between deleting one ribosomal protein gene (RPG) paralog and oxidative stress response. Our results indicated that RPG mutants exhibited higher oxidant sensitivity than the wild type (WT). The concentrations of H2O2 were increased in the RPG mutants. Catalase and superoxide dismutase (SOD) activities were generally higher at the stationary phase, with catalase showing particularly elevated activity in the RPG mutants. While both catalase genes, CTT1 and CTA1, consistently exhibited higher transcription in RPG mutants, Ctt1 primarily contributed to the increased catalase activity. Stress-response transcription factors Msn2, Msn4, and Hog1 played a role in regulating these processes. Previous studies have demonstrated that H2O2 can cleave 25S rRNA via the Fenton reaction, enhancing ribosomes' ability to translate mRNAs associated with oxidative stress-related genes. The cleavage of 25S rRNA was consistently more pronounced, and the translation efficiency of CTT1 and CTA1 mRNAs was altered in RPG mutants. Our results provide evidence that the mutations in RPGs increase H2O2 levels in vivo and elevate catalase expression through both transcriptional and translational controls.</p>","PeriodicalId":12290,"journal":{"name":"FEMS yeast research","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10855018/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139563595","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Degradation of citrate synthase lacking the mitochondrial targeting sequence is inhibited in cells defective in Hsp70/Hsp40 chaperones under heat stress conditions.","authors":"Mayuko Hayashi, Tomoyuki Kawarasaki, Kunio Nakatsukasa","doi":"10.1093/femsyr/foad054","DOIUrl":"10.1093/femsyr/foad054","url":null,"abstract":"<p><p>Most nucleus-encoded mitochondrial precursor proteins are synthesized in the cytosol and imported into mitochondria in a post-translational manner. In recent years, the quality control mechanisms of nonimported mitochondrial proteins have been intensively studied. In a previous study, we established that in budding yeast a mutant form of citrate synthase 1 (N∆Cit1) that lacks the N-terminal mitochondrial targeting sequence, and therefore mislocalizes to the cytosol is targeted for proteasomal degradation by the SCFUcc1 ubiquitin ligase complex. Here, we show that Hsp70 and Hsp40 chaperones (Ssa1 and Ydj1 in yeast, respectively) are required for N∆Cit1 degradation under heat stress conditions. In the absence of Hsp70 function, a portion of N∆Cit1-GFP formed insoluble aggregates and cytosolic foci. However, the extent of ubiquitination of N∆Cit1 was unaffected, implying that Hsp70/Hsp40 chaperones are involved in the postubiquitination step of N∆Cit1 degradation. Intriguingly, degradation of cytosolic/peroxisomal gluconeogenic citrate synthase (Cit2), an endogenous substrate for SCFUcc1-mediated proteasomal degradation, was not highly dependent on Hsp70 even under heat stress conditions. These results suggest that mitochondrial citrate synthase is thermally vulnerable in the cytosol, where Hsp70/Hsp40 chaperones are required to facilitate its degradation.</p>","PeriodicalId":12290,"journal":{"name":"FEMS yeast research","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10786195/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138829130","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}