Scientific Program

Day 1

KEYNOTE SPEAKERS
  • Coping with Stress: Lessons from Yeast

    Penn State College of Medicine
    USA
    Biography

    Dr. Broach is Chair of the Department of Biochemistry and Molecular Biology at Penn State Hershey, Director of the Penn State Institute for Personalized Medicine and Professor Emeritus of Princeton University. He completed his undergraduate studies in Chemistry at Yale University in 1969 and his Ph.D. in Biochemistry from the University of California, Berkeley in 1973, where he also completed a Postdoctoral Fellowship in Medical Physics. Dr. Broach served on the Scientific Review Board of the Frederick Cancer Center of the National Cancer Institute and has served as a member of both the Genetics and the Genomics Study Sections and Chair of the Genomics, Computational Biology and Technology Study Section of the National Institutes of Health. He was Co-Founder and Director of Research for Cadus Pharmaceuticals and sits on the Board of Directors of Cadus Corporation. Dr. Broach was Professor of Molecular Biology at Princeton University from 1984-2012, where he served as Associate Director of the Lewis Sigler Institute for Integrative Genomics and Co-Director of the Center for Computational Biology. Dr. Broach is a Fellow of the American Academy of Microbiology and the Co-Director of the Life Sciences Research Foundation, a private organization that provides postdoctoral fellowships in the life sciences. Dr. Broach is a member of the Science Board of the Food and Drug Administration and served as Trustee of the University of Medicine and Dentistry of New Jersey and Commissioner on the New Jersey Commission on Cancer Research until 2012. He is a member of the executive committee of the Cancer Biology Training Consortium, a national organization promoting graduate and postdoctoral training in cancer biology. Dr. Broach has published more than 150 articles in the area of molecular biology and holds a number of patents in drug discovery technologies.

    Abstract

    Yeast cells subjected to many different stresses elicit an acute transcriptional stress response mediated by the Msn2 transcription factor, which alters expression of both a stress specific cohort of genes as well as a common cohort of genes that changes expression in a stereotypic fashion upon exposure to any of a wide variety of stresses. We have shown by dynamic single cell analysis that stresses regulate Msn2 activity through cytoplasmic to nuclear relocalization but do so in an unusual way: stresses induce increased frequency of bursts of short-lived, recurrent periods of Msn2 nuclear localization with different stresses eliciting different patterns of bursts. Moreover, genetically identical cells subjected to an identical stress can behave quite differently. We have proposed that this idiosyncratic behavior allows populations of cells to “hedge their bet” as to what will be the optimal strategy for surviving ensuing stress. We have used computational modeling and single cell analysis to determine that bursting is a consequence of the noise in the stress signaling pathways, amplified by the small number of Msn2 molecules in the cell. Moreover, we have applied genome wide chromatin immunoprecipitation and nucleosome profiling to address how different stresses determine where Msn2 binds under a particularly stressful condition, and thus what genes are regulated by that stress and how that binding affects, and is affected, by nucleosome positioning and other transcription factor binding. These results provide an in vivo validation of indirect cooperativity of transcription factor binding, mediated by partial unwinding of nucleosomes by one transcription factor to allow access for a second transcription factor to a previously occluded binding site. Finally, we have addressed the “bet hedging” hypothesis by showing that persistence of the Msn2-mediated stress response yields cell growth arrest and have identified the targets responsible for that growth arrest. We have applied experimental evolution paradigms to address the relative fitness of cells exhibiting stochastic stress response versus those with a uniform response. In short, our results indicate that the stress response is complex and that complexity is critical for cell survival.

  • Yeasts membrane constituents and their potential beneficial effect against colorectal cancer

    INRS-Institut Armand-Frappier
    Canada
    Biography

    Monique Lacroix has completed a B.Sc.A. and a M.Sc. in Food Sciences Technology in 1980 and 1982 respectively and a Ph.D. in Nutrition in 1986. She is full professor at INRS-Institut Armand-Frappier, Canada and director of the Research Laboratories in Sciences Applied to Food and of the Canadian Irradiation Centre. Prof. Lacroix is Fellow of the International Academy of Food Science and Technology (IAFoST) for her outstanding representatives of international food science and technology; she received 4 awards for her most cited publications in Food sciences and for the best 10 research partnership with industries for two partnerships. Professor Lacroix has served as an expert member of several United Nations research networks on food safety and on nano biopolymer using gamma irradiation. She is also member of three Canadian networks: Canadian food processing networks, Research network on dairy products in Québec and of the Institute of nutraceuticals and functional foods. Professor Lacroix is author of more than 264 publications, 10 patents and 21 book chapters. Until today, she has supervised 14 post-doct, 98 graduated students of 2nd and 3 th cycles and over than 315 trainees that come from all over the world. She has been invited to present over than 188 conferences in major congresses, including United Nations conferences as a member of expert committees.

    Abstract

    Colorectal cancer (CRC) is one of the third most common diagnosed cancers in westerns countries. Diet and life style have important rules as preventive methods and still seem to be the most efficient approach. Consumption of diet containing agents with CRC preventive properties could reduce the risks of CRC incidence. Cancer prevention properties could be obtained via cancer cells cytotoxicity, apoptosis, antioxydant and via enzymatic modulation. QR is a phase II detoxification enzyme recognized to protect against toxic metabolites involved in the first stage of carcinogenesis process and can decreases chemical carcinogenicity compounds by transforming them to compounds with less toxicicity. ?-glucuronidase enzyme can release carcinogenic compounds in the colon. A reduction its activity can lead to a reduced exposure to carcinogenic substance. Saccharomyces boulardii and Kluyveromyces marxianus are well-known yeasts in food industry. Their membrane are composed of insoluble (47%) and soluble glucan (36%) and mannoprotein (0.45%). Our studies showed that mannoprotein of K. marxianus exhibit the most relevant antioxidant activity probably due to the presence of aromatic amino acids and thiol groups but only insoluble glucan from both yeast species can induce Quinone Reductase (QR) enzyme activity. Cell wall extracts of both yeast cells, are able to inhibit the growth of HT 29 cells colon cancer cells by more than 50% and extracts of S. boulardii show the lowest IC50 values. In vivo studies with rats demonstrated that ingestion of crude insoluble glucan (0?5mg kg-1 day-1), obtained from S. boulardii cell wall exhibited colon cancer prevention properties and enzymatic modulation is one of the mechanism observed. An induction of more than 68% of the QR specific activity and a reduction of more than 50% of the ?-glucuronidase activity was found. Also, a reduction of more than 45% the total count of aberrant crypt (AC), 50% of aberrant crypt foci (ACF) and a 73% reduction of the total number of ACF containing 4-5 AC per focus in the animal colon was observed. Extraction of S. boulardii and K. marxianus yeast cells wall via simple and fast extraction can be proposed for the development of a new nutraceutical product against colon cancer.

  • Yeast dynamin plays a key role in the endosome-to-Golgi Traffic

    Missouri State University
    USA
    Biography

    Dr. Kyoungtae Kim is a professor at Missouri State University in Springfield, MO. He received his B.A. and M.A. in Biological Science at Kyungpook National University in Taegu, Korea. He went on to obtain his Ph.D. in Biology at Florida State University in Tallahassee, Florida, and completed his post-doc at Washington University in St. Louis, MO, where he studied cell biology and physiology. He is now located at Missouri State University where his research focuses on diverse cellular processes, including endocytic pathway, intracellular trafficking of proteins and membranes, membrane organization, nanomaterial traffic, and nanomaterial-mediated global gene expression pattern changes.

    Abstract

    Yeast dynamin (Vps1) has been implicated in recycling traffic from the endosome to the trans-Golgi network (TGN). We previously revealed a genetic interaction of Vps1 with Ypt6 and all components of the GARP tethering complex that anchors an incoming vesicle to TGN membrane. The present study identified a 33 amino acid segment of Vps51, a GARP subunit, that interacts with Vps1. Based on sequence homology between Vps51 and its mammalian homolog Ang2, we identified two key residues of Vps51, E127 and Y129, that bind Vps1. The replacement of these residues led to severe defects in endosome-to-TGN transport of Snc1, providing evidence of the physiological relevance of the interaction of Vps51 with Vps1 for the traffic. Furthermore, our functional analysis revealed that Vps1 acts upstream of Vps51 and that the absence of Vps1 resulted in defects in targeting of Vps51 and its binding partner Tlg1 to the TGN. The present study also reveals that Vps1 physically interacts with Ypt6. Interestingly, severe defects in retrograde trafficking caused by loss of Ypt6 were rescued by overexpression of Vps1, and vice versa. Furthermore, overexpression of Vps1 GTPase mutants was not sufficient enough to rescue abnormal Snc1 recycling in ypt6? cells. These results suggest that the GTP binding and hydrolysis of Vps1 is essential for this trafficking pathway and that Vps1 and Ypt6 may function parallel. Finally, this study shows that Vps1 interacts with two SNARE proteins, Vti1 and Snc2, functioning for endosome-derived vesicle fusion at the TGN, pointing to a novel role of Vps1 in the late stage of the endosome-to-Golgi traffic. Therefore, we propose that Vps1 and Ypt6 converge on the GARP tethering machinery for efficient tethering/fusion at the TGN.

  • The Ins and Outs of Nitrogen-Responsive Gene Regulation in Saccharomyces cerevisiae.

    University of Tennessee Health Science Center
    USA
    Biography

    Cooper investigated avian oil droplets as an undergraduate, obtained a M.S. in Chemistry studying carboxylase enzyme mechanisms at Wayne State and a Ph.D. at Purdue first discovering that ?-oxidation occurs in peroxisomes rather than mitochondria. With Magasanik at MIT he investigated the mechanism of carbon catabolite repression in E. coli. While there he and Patricia Whitney discovered yeast urea amidolyase to be a multifunctional protein consisting of urea carboxylase and allophanate hydrolase. Moving to the University of Pittsburgh, he and his students elucidated the reactions of the allantoin degradative pathway, proposed nitrogen catabolite repression (NCR) as controlling nitrogen-responsive gene expression and he authored “The Tools of Biochemistry”. Cooper learned the intricacies of yeast genetics from Sye Fogel and cloning from John Carbon. His group identified, mapped, cloned and sequenced the allantoin pathway structural and four GATA-transcriptional regulatory genes. As Harriet S. Van Vleet Professor at the University of Tennessee he founded and directed the Molecular Resource Center and was chair of Microbiology and Immunology for 15 years. His students identified the promoter structures of the NCR-sensitive genes, binding sites for their four regulatory transcription factors and now the regulatory pathways controlling Gln3 localization and intra-nuclear regulation. He served 17 years on and chaired NIH and ACS study sections, chaired the AAMC Council of Academic Societies, served on the AAMC Executive Committee, multiple editorial boards and as treasure and American representative to the International Conference of Yeast Genetics and Molecular Biology. He is currently a member of the UT Board of Trustees.

    Abstract

    Yeast cells have evolved to maintain steady internal nitrogen homeostasis in the face of continuous and drastic transitions in its environmental nitrogen supply. Cells are able to take full advantage of luxurious nitrogenous environments, while retaining the ability to successfully cope with those that are more austere. This Nitrogen Catabolite Repression (NCR) sensitive control is achieved through the regulation of the GATA-binding transcription activators, Gln3 and Gat1. In nitrogen replete conditions Gln3 and Gat1 are efficiently sequestered in the cytoplasm and as a result, NCR-sensitive transcription is minimal. As nutritional conditions deteriorate, Gln3 and Gat1 relocate to the nucleus and dramatically increase GATA factor-mediated transcription of the genes required to import and catabolize poor nitrogen sources scavenged from the environment. TorC1 kinase complex was originally thought to be the principle contributor to NCR-sensitive Gln3 regulation. However, Gln3 responds to 5 distinct physiological conditions each exhibiting a unique set of regulatory requirements. This argued that NCR-sensitive control was more complex than appreciated. Using amino acid substitutions throughout the disordered Gln3 protein, we show that nitrogen-responsive TorC1 control only partially accounts for NCR-sensitive regulation. Uncharged tRNA-activated, Gcn2 kinase-mediated General Amino Acid Control (GAAC) is equally critical with the Gcn2 and TorC1 kinases functioning independently and in opposition to one another. Epistasis experiments indicate Gcn2 likely functions upstream of Ure2, whereas the 14-3-3 proteins Bmh1/2, also required for nuclear Gln3 localization, likely function downstream. Nuclear Gln3 import is also more complex than previously appreciated requiring two additional Nuclear Localization Sequences (NLS) in addition to the previously reported NLS1 as well as a newly identified Ure2 Relief Sequence. A third level of Gln3 regulation is imposed within the nucleus. In high glutamine, Gln3 exits from the nucleus in the absence of binding to its GATA targets within NCR-sensitive promoters. In contrast, as glutamine levels decrease, GATA binding becomes requisite for Gln3 to exit from the nucleus. It is only through the concerted actions of this full array of regulatory components that NCR can effectively manage intra-cellular homeostasis in the face of unreliable environments. GM35642-27.

Genetics and Molecular Biology
Speaker
  • Functional upregulation of ribosome biogenesis in yeast treated with Silver or CdSe/ZnS nanoparticles.
    Speaker
    Kyoungtae Kim
    Missouri State University
    USA
    Biography

    Dr. Kyoungtae Kim is a professor at Missouri State University in Springfield, MO. He received his B.A. and M.A. in Biological Science at Kyungpook National University in Taegu, Korea. He went on to obtain his Ph.D. in Biology at Florida State University in Tallahassee, Florida, and completed his post-doc at Washington University in St. Louis, MO, where he studied cell biology and physiology. He is now located at Missouri State University where his research focuses on diverse cellular processes, including endocytic pathway, intracellular trafficking of proteins and membranes, membrane organization, nanomaterial traffic, and nanomaterial-mediated global gene expression pattern changes.

    Abstract

    Nanoparticles are commercially used in everyday products including zinc sunscreen and water resistant fabrics and surfaces, but in the future they may be used in the targeted treatment of cancer, printable monitoring systems, and affordable phones. Understanding the effects of nanoparticles on biological organisms is crucial for the responsible use of these technologies. We investigated the effects of silver (Ag) and cadmium (CdSe/ZnS) nanoparticles on the budding yeast Saccharomyces cerevisiae using growth assays, FUN-1 staining for metabolic activity, RNAseq, and RTPCR. Our growth assay showed that Ag has an inhibitory effect with its concentrations above 5µg/ml, whereas SdSe/ZnS had no effect on cell growth. Interestingly, cells treated with 5µg/ml Ag showed no metabolic defects. Hundreds of the same genes in both Ag and CdSe/ZnS treated cells were differentially expressed according to our transcriptome investigation, the majority of which are responsible for ribosomal biogenesis and nucleotide binding. Furthermore, we validated the RNAseq results using an RTPCR assay. The resulting expression profile leads us to suspect that Ag and CdSe/ZnS nanoparticle exposure creates a stress environment in the cell.

  • A novel plasma membrane regulator of calcium homeostasis in yeasts
    Speaker
    Linghuo Jiang
    Shandong University of Traditional Chinese Medicine
    China
    Biography

    Linghuo Jiang has completed his PhD in 1999 from University of Alberta, Canada and postdoctoral studies from University of Virginia School of Medicine and the Biotechnology Research Institute of Natural Sciences and Engineering Research Council of Canada. He is a Professor of Shandong University of Technology School of Agricultural Engineering and Food Science. His areas of research are Molecular Biology of yeasts and Fermentation Technologies. He has published more than 50 papers in reputed journals and has been serving as an editorial board member for three journals, BMC Genetics, FEMS Yeast Research and Microbiological Research. He gave oral presentations in both the Cold Spring Harbor Laboratory meeting “Cell Biology of Yeasts”, New York, USA in 2013 and the 13th International Congress on Yeasts. Madison, Wisconsin, USA in 2012.

    Abstract

    Homologous to the vertebrate solute carrier SLC10A7, Rch1 is a novel regulator of calcium homeostasis in the plasma membrane of the budding yeast Saccharomyces cerevisiae and the human yeast pathogen Candida albicans. ScRCH1 is a functional homolog of CaRCH1. ScRch1 and CaRch1 negatively regulate the calcium uptake in response to high levels of extracellular calcium in S. cerevisiae and C. albicans, respectively. However, CaRch1 is constitutively expressed, while ScRch1 is induced by a high level of calcium ions. Transcriptional expression of ScRCH1 is positively regulated by calcium/calcineurin signaling through the sole CDRE element in its promoter. Furthermore, distribution of ScRch1 proteins in the plasma membrane changes in a dynamic way, from multiple foci prior to cell division, accumulation at the bud neck during bud growth, and dispersion along the plasma membrane immediately prior to cytokinesis. Rch1 is a novel member regulating calcium homeostasis in yeasts.

  • Regulation of the mitochondrial functions by phosphorylation in the yeast Saccharomyces cerevisiae
    Speaker
    LEMAIRE Claire
    Paris-Sud University
    France
    Biography

    Dr. Claire Lemaire is expert in the biochemistry of membrane proteins. Her scientific interests have always been focused on energy-transducing systems and in particular those evolved in organelles. She began her career in the photosynthesis field on the assembly and regulation of photosynthetic complexes (Institute of Physico-Chemical Biology, Paris). She then joined the C.N.R.S. (French National Center for Scientific Research) where she has acquired an excellent appreciation of the mitochondrial system through the study of the biogenesis of respiratory complexes in yeast and human using various biochemical and genetic approaches. These last years, she has developed a new research project with her group focusing on the regulation of the mitochondrial functions by post-translational modifications.

    Abstract

    The mitochondrion is an organelle of which the most important function is to provide energy to the cell generated by oxidative phosphorylation catalyzed by the respiratory enzymes. In humans, deregulation of mitochondrial functions, particularly with regard to the respiratory chain, is associated with several pathologies. The activity of the respiratory enzymes may be modulated in response to metabolic demand and various types of stress. Several levels of regulation may be conceived, including post-translational modifications such as phosphorylation. The steadily increasing number of identified mitochondrial phosphoproteins suggests that reversible protein phosphorylation could be an important level of regulation in mitochondria. However, this hypothesis cannot be tested without quantitative data on variations in the abundance of mitochondrial proteins and their level of phosphorylation under different growth conditions. The yeast Saccharomyces cerevisiae is a powerful tool for studying various energetic and physiological states. We realized for the first time a quantitative study of both protein abundance and phosphorylation levels in yeast mitochondria under respiratory (lactate) and fermentative (glucose or galactose) conditions. Protein abundances were quantified using a label-free method. The phosphoproteome was analyzed quantitatively using the multiplex stable isotope dimethyl labeling procedure. Label free quantitative analysis of protein accumulation revealed significant variation of 176 mitochondrial proteins. We highlighted significant differences of the proteome between the two fermentative substrates.This study enlarges significantly the map of yeast mitochondrial phosphosites as 670 phosphorylation sites were identified, of which 214 were new and quantified. Above all, we showed that 90 phosphosites displayed a significant variation according to the medium. This proteomic and phosphoproteomic study is the first extensive study providing confident quantitative data on mitochondrial phosphosites responses to different carbon substrates in the yeast S. cerevisiae mitochondria. The significant changes observed in the level of phosphorylation according to the carbon substrate open the way to the study of the regulation of mitochondrial proteins by phosphorylation in fermentative and respiratory media. In addition, the identification of a large number of new phosphorylation sites show that the characterization of the yeast mitochondrial phosphoproteome is not yet completed.

Fermentation and Biotechnology
Speaker
  • Improvement of chocolate flavor by yeast during cocoa fermentation
    Speaker
    Rosane Freitas Schwan
    Universidade Federal de Lavras
    Brazil
    Biography

    Dr. Rosane Freitas Schwan is a Full Professor within the Microbiology Group, Department of Biology at the Federal University of Lavras, Minas Gerais, Brazil, where she is involved in research on the microbiology of fermented foods and beverages. Prof. Schwan is Agricultural engineer from the Federal University of Espírito Santo, MSc. at UFV (Viçosa-MG) and PhD from the University of Bath (UK). Dr. Schwan was a researcher in the Cocoa Research Centre (CEPLAC) (1984-1996), where published techniques for improving the quality of the chocolate. At UFLA, since 1996, conducts research with coffee fermentation, sugar cane, cocoa, cassava and other substrates to improve the quality and development of new processes for foods and beverage. She is currently Director of the culture collection of agriculture microbiology - CCMA in DBI/UFLA, and Associate Editor of the Brazilian Journal of Microbiology and Food Microbiology. Supervisor of several MSC and PhD students from the programs in Agricultural Microbiology and Food Science in UFLA. Authored numerous publications addressing different aspects of knowledge and microbial biodiversity of natural and spontaneous fermentative processes over almost 30 years and recently, recently, she co-edited a volume in the CRC series in Fermented foods and beverages Series on Cocoa and Coffee Fermentation.

    Abstract

    Cocoa research performed during the last century has elucidated the basic physiology and ecology of cocoa fermentation and the biochemical changes that occur during cocoa fermentation, drying and roasting that lead to the development of the chocolate flavour. Biotechnological manipulation of the steps of microbial fermentation (microorganisms, amount of pulp, selected strains) can result in understandable and reasonably predictable effects on chocolate quality. Many different species of microorganisms have been isolated from cocoa fermentation and have been characterised and the microbial succession has been defined. Yeast are essential to the fermentation process and development of chocolate flavour. The concept of using starter cultures to conduct cocoa bean fermentations is not new. Initially, around 1960- 1980, the aim was to induce a faster, more consistent fermentation, without adverse impact on chocolate quality. More specific investigations on the use of starter cultures have now been conducted where the main goals have been to develop a faster, more consistent fermentation process that yields cocoa beans with predicable qualities. The dynamic of Saccharomyces cerevisiae, Pichia kluyveri and Hanseniaspora uvarum during spontaneous and inoculated cocoa fermentations and their effect on sensory characteristics of chocolate were investigated. Yeast populations were assessed by qPCR. S. cerevisiae was predominant during spontaneous (average 5.4 log cell/g) and inoculated (average 7.2 log cell/g) fermentations. The H. uvarum seemed to be suppressed by the other two yeasts, as it showed similar population (approximately 4.0 log cell/g) even in the inoculated assay. Carbohydrates were consumed quickly at inoculated fermentation (68% and 42% were consumed in the inoculated and control assays respectively, at 24 h). Ethanol content was higher in the inoculated (8.3 g/kg at 48 h) than in the control (4.6 g/kg at 96 h) fermentation. Chocolate produced from the spontaneous fermentative process presented dominance of the bitter flavour, while obtained through inoculated fermentation process presented bitter, astringent, coffee and acid as dominant flavours. The inoculation accelerated the fermentative process in 48 h. The inoculation of yeast influenced the microbial profile, which affected the volatile compounds that affect sensory characteristics, resulting in chocolate with dominant bitter, cocoa, and fruity attributes.

Bioenergy and Biofuels
Speaker
  • Bioethanol Production by Thermotolerant Yeast Kluyveromyces marxianus from Sugarcane Bagasse
    Speaker
    Sachin Kumar
    Sardar Swaran Singh National Institute of Bio-Energy
    India
    Biography

    Dr. Sachin Kumar has been working as a Deputy Director in the Biochemical Conversion Division at the Sardar Swaran Singh National Institute of Bio-Energy, Kapurthala, India. He has also worked as Visiting Professor in the Department of Chemical and Biological Engineering at the South Dakota School of Mines and Technology, Rapid City, USA for one year. He completed his Ph.D. in Chemical Engineering from Indian Institute of Technology Roorkee, India. He has more than twelve years of research experience in Biochemical Conversion of Biomass to Biofuels including lignocellulosic ethanol, biogas, biohydrogen, etc. He has completed six research projects and one consultancy project and actively engaged in two on-going research projects. He has published more than 50 research papers in peer reviewed journals, book chapters and papers in conference proceedings and 07 edited books. He has been granted one US patent and one filed patent in India. He has delivered about 17 invited/plenary lectures and read more than 70 papers in national and international conferences. He is a recipient of 2016 ASM-IUSSTF Indo-US Research Professorship and selected as Bioenergy-Awards for Cutting Edge Research (B-ACER) Fellow 2016 by DBT and IUSSTF. He is serving as an editor, associate editor and editorial board member of various peer reviewed journals. He has coordinated three national & two international conferences and five national training programs.

    Abstract

    Second generation (2G) bioethanol is a clean and renewable source of energy, which could be produced by lignocellulosic biomass (LCB) such as agricultural, forestry, municipal, and industrial wastes. LCB contains cellulosic and hemicellulosic fractions, which is yielded into pentose and hexose sugars using pretreatment and enzymatic saccharification. Most of the ethanol producing microorganisms are either hexose sugars utilizing or utilize pentose sugars inefficiently along with hexose sugars. However, the utilization of both pentose and hexose sugars is required for economical fuel ethanol production. An isolated thermotolerant yeast Kluyveromyces marxianus NIRE-K3 is able to utilize both pentose and hexose sugars. However, the utilization of pentose sugar (xylose) is very slow as compared to hexose sugar (glucose). The present study was carried out to develop K. marxianus NIRE-K3.2 for enhanced xylose utilization through two-phase evolutionary adaptation, and analyzed the bioethanol production potential of adapted K. marxianus NIRE-K3.2 from sugarcane bagasse (SCB) in comparison to native yeast. The two-phase evolutionary adaptation was carried out: first in YEPX medium (20 g l -1 xylose) for 60 generations followed by second in minimal salt medium containing 20 g l -1 xylose for 55 generations. Liquid ammonia pretreated SCB was enzymatically saccharified using Novozyme Cellic Ctec2. The maximum concentrations of glucose and xylose in hydrolysate were found to be 35.45 g l -1 , and 14.92 g l -1 , respectively. The fermentation of enzymatic hydrolyzate was carried out using native NIRE-K3 and adapted NIRE-K3.2, separately at 45 o C and pH 5.5. NIRE-K3 showed utilization of 43.23 % xylose, whereas, NIRE-K3.2 utilized 75.06 % xylose present in hydrolyzate. The ethanol yields obtained by NIRE-K3.2 was equivalent to 92.15 % of the theoretical yield, whereas, 60.78 % in case of NIRE-K3. The adapted strain NIRE-K3.2 showed 34 % improved ethanol yield by utilizing xylose efficiently along with glucose as compared to that of native strain. The aforesaid results show the importance of evolutionary adaptation to develop enhanced xylose utilizing thermotolerant yeast K. marxianus NIRE-K3.2 for bioethanol production by utilizing both pentose and hexose sugars in SCB.

Yeast-Based Drug Discovery
Speaker
  • Heterologous expression of cyclic nucleotide-metabolizing enzymes for drug discovery using Schizosaccharomyces pombe and PKA-repressed reporters
    Speaker
    Charles S. Hoffman
    Boston College
    USA
    Biography

    Charles S. Hoffman received an SB in Life Sciences from MIT and a PhD in Molecular Biology and Microbiology from the Tufts University Sackler School of Graduate Biomedical Sciences. He conducted postdoctoral studies at the Harvard Medical School Department of Genetics, where he began his studies of glucose/cAMP signaling and transcriptional regulation of the fbp1 gene in Schizosaccharomyces pombe. He has been a faculty member of the Boston College Biology Department since 1990, and has published more than 60 papers and book chapters. He is an Associate Editor for both Current Genetics and G3 Genes| Genomes| Genetics, and is a member of the Luxuriant Flowing Hair Club for Scientists and the Scotch Malt Whisky Society of America.

    Abstract

    The fission yeast Schizosaccharomyces pombe cAMP/PKA pathway is ideal for chemical genetics as it is not essential, thus allowing one to replace either the S. pombe adenylyl cyclase (AC) that produces cAMP or the phosphodiesterase (PDE) that hydrolyzes cAMP with genes encoding related proteins from other organisms. Our strain collection includes strains expressing 15 of the 21 mammalian PDE genes, all 10 of the mammalian AC genes, and both wild type and mutationally-activated forms of the human GNAS G? that stimulates the activity of the mammalian transmembrane ACs. In addition, the S. pombe fbp1 gene is transcriptionally-repressed by PKA such that an fbp1-ura4 reporter can be used to detect PDE inhibitors by their ability to confer 5FOA-resistant growth, while fbp1-GFP and fbp1-luciferase reporters can be used to detect AC and/or GNAS inhibitors that confer increased reporter expression. One advantage of this screening platform is that compounds identified in these screens are cell permeable. In the case of the PDE inhibitors, hit compounds must be highly selective for binding as a promiscuously-binding compound would likely inhibit cell growth. Prior screens for PDE inhibitors have identified PDE4 and PDE7 inhibitors that display anti-inflammatory activity in mammalian cell culture, a PDE4/7 inhibitor that induces apoptosis in CLL cells, a PDE4/8 inhibitor that elevates testosterone production by Leydig cells, and a PDE11 inhibitor that elevates cortisol production by adrenocortical cells. Our most recent HTS has been for inhibitors of GNAS or AC9, as the mutationally-activated is found in McCune-Albright patients, as well as in many patients with pancreatic intraductal papillary mucinous neoplasms and associated adenocarcinomas. Current efforts are underway to profile the activity of these putative AC and GNAS inhibitors.

  • Antifungal photodynamic therapy: an overview
    Biography

    Wanessa Melo has completed her PhD at the age of 29 years in Science with especial focus in microbial infection at Universidade de São Paulo-Brazil. Part of her PhD was realized under Dr. Michael Hamblin supervision at Massachusetts General Hospital and Havard Medical School – Boston-MA. Her postdoctoral was performed at Universidade Estadual de São Paulo – Brazil, evaluating the activity of photodynamic therapy against fungal biofilms. Currently, she is professor-research at Faculdade de Guanambi-Brazil, where she develops several studies in photodynamic therapy area.

    Abstract

    Fungi have become increasingly recognized as major pathogens in critically ill patients. The incidences of superficial and systemic fungal infections have increased markedly and caused a public health problem. Some factors may contribute to rise the occurrence of fungal infections, highlighting that antifungal treatment is limited to a very small number of drug substances; in many cases the treatment is ineffective, especially, due the arising of resistant fungal strains; very often the treatment is prolonged and serious side effects and drug–drug interactions are common. These problems have renewed the search for alternative treatment modalities, and antimicrobial photodynamic therapy (aPDT) seems to be a potential candidate. Several studies have been show that dermatophytes and yeasts can be effectively inhibited in vitro and in vivo by aPDT, causing a minimal damage to host cells. This therapy employs a photosensitizer (PS), visible light, and molecular oxygen to produce cytotoxic reactive oxygen species (ROS) that lead to apoptosis. So, my presentation aims to raise awareness of this area of research, which has the potential to make a significant impact in future treatment of fungal infections.

  • Yeast as a test-bed for drug discovery: from target engagement to drug resistance
    Speaker
    Corey Nislow
    THE UNIVERSITY OF BRITISH COLUMBIA
    Canada
    Biography

    Corey Nislow completed his PhD in 1994 from University of Colorado, was an American Cancer Society Post-Doctoral Fellow, spent 6 years working in several Bay Area Biotechs and has co-led (with Guri Giaever) genomics laboratories at Stanford, University of Toronto and University of British Columbia. He is the Director of the UBC Sequencing and Bioinformatics Consortium and co-founder of Genetic Networks, LLC. He has published more than 165 papers and 9 patents.

    Abstract

    Saccharomyces cerevisiae has served as genetic model organism for over a century, as a genomic powerhouse since it was the first eukaryote to have its genome sequenced in 1996, and more recently as a test-bed for the development and application of chemogenomic assays. Baker’s yeast has also provided fundamental insights into evolutionary conserved biology as witnessed by three Nobel prizes attributable to yeast- in cell-cycle biology, secretion and autophagy. Its simplicity of cultivation, combined with its functional conservation allows for the discovery of novel chemical probes which can serve as tools to probe biological function and new leads for drug discovery. In this talk I will describe how the HIHOP laboratory, established by Guri Giaever, has deployed yeast-based assays to 1) discover novel-target-drug interactions, 2) understand the mechanism by which drug resistance develops and 3) map the chemical-genetic portrait of an organism.

Fermentation and Yeast Biotechnology
Speaker
  • Naganishia qatarensis sp. nov. novel basidiomycetous yeast species from hypersaline marine environment
    Speaker
    Dr.Rashmi Fotedar
    Ministry of Municipality and Environment
    Qatar
    Biography

    Dr. Rashmi Fotedar has completed his PhD at the age of 27 years from All India Institute of Medical Sciences, New Delhi, India. She is working as Expert of Microbiology and Molecular biology at the Ministry of Municipality and Environment, Qatar. She has published more than 35 papers in reputed journals.

    Abstract

    Two yeast strains isolated from the hypersaline marine environment from Inland Sea, Qatar, were classified as members of the genus Naganishia based on sequence analysis of the D1/D2 domains of the large subunit rRNA gene and the internal transcribed spacer (ITS) regions. The rRNA gene sequence analyses indicated that the two strains represented a novel species of the genus Naganishia, for which the name Naganishia qatarensis sp. nov. is proposed. They clustered in a strongly supported clade represented by Naganishia albidus in the Tremellales group in the phylogenetic tree drawn from ITS and D1/D2 sequence. The new species grows at 4°C and 35 °C. The significance of findings will be discussed.

  • Benefits of probiotic yeasts in human and animal health
    Speaker
    Ashima Vohra
    University of Delhi
    India
    Biography

    Dr. Ashima Vohra has published seven research papers in peer reviewed journals and has ten chapters/reviews in books to her credit. She also has two Indian Patents. She received the prestigious Young Scientist Award of the Indian National Science Academy in 2005. She also received Young Scientist award in 1999 at the International Conference on ‘Frontiers in Fungal Biotechnology and Plant Pathogen Relations’ at Osmania University, Hyderabad in January 16-18, 1999 for best oral presentation. She was awarded the All India Post graduate Scholarship from 1995-1997. She is a life member of AMI (Association of Microbiologists of India).

    Abstract

    Saccharomyces boulardii is emerging as potential probiotic organism. This yeast has shown promising results in preventing enteral nutrition-related diarrhoea, acute gastroenteritis, traveler’s diarrhoea and decreasing Helicobacter pylori treatment-related symptoms. The role of S. boulardii for both the prevention of Antibiotic-associated diarrhoea (AAD) and treatment of irritable bowel syndrome and recurrent C. difficile disease, Crohn’s disease, and giardiasis has been clearly demonstrated. Probiotic yeast has been considered superior over probiotic bacteria because of the natural resistance of yeast to antibacterial antibiotics. Probiotic yeasts have also shown a positive effect on poultry health and nutrition by reducing lactic acid acidosis, increasing fiber digestibility, secreting enzymes and improving animal performance by enhancing their growth rate and increasing milk, meat and eggs production. In the present study Saccharomyces cerevisiae Id18 isolated from traditional Indian fermented food – idli batter, exhibited probiotic attributes such as acid and bile salt tolerance, ability to grow at 37ºC, resistance to commonly used antibiotics, auto-aggregation ability and cell surface hydrophobicity. It showed antimicrobial action against enteric pathogens. It produced phytase, ?-galactosidase, vitamin B12 and exopolysaccharides. It had the ability to assimilate cholesterol. This probiotic yeasts when used either alone or in combination with traditional dairy starter, significantly improved the nutritional properties and the shelf life of the fermented dairy product.

Yeast infections
Speaker
  • The roles of checkpoint related protein phosphatases and regulators in regulating morphogenesis and virulence in Candida albicans
    Speaker
    Jinrong Feng
    Nantong University School of Medicine
    China
    Biography

    Jinrong Feng has completed his Ph.D. in 2010 from Tianjin University, China. Now he is an associate professor of School of Medicine, Nantong University. He mainly focused on checkpoint related protein phosphatases in Candida albicans. He has published over 10 papers in reputed journals.

    Abstract

    Phosphorylation and dephosphorylation of the checkpoint kinase CaRad53 is crucial for fungal cells in response to genotoxic stresses. The catalytic subunit CaPph3 of protein phosphatase 4 (PP4) forms a complex with the regulatory subunit CaPsy2, which dephosphorylates activated CaRad53 during adaptation to and recovery from MMS-mediated DNA damage. We show here that the N-terminal Y33A mutation of CaPsy2 blocks the interaction between CaPph3 and CaRad53, the deactivation of CaRad53 and the morphologic switch in recovery from genotoxic stress. In Saccharomyces cerevisiae, the ScPph3-ScPsy2-ScPsy4 complex functions to dephosphorylate ?H2A. Here, we also show that CaPsy4 is a functional homolog of ScPsy4, but not involved in the deactivation of CaRad53 or CaHta, the ortholog of H2A. However, deletion of CaPSY4 causes C. albicans cells a sensitivity to genotoxic reagents and a defect in DNA damage-induced filamentation. In S. cerevisiae, ScTip41 and ScTap42 are two regulators of CaPph3. In C.albicans, we show that deletion of CaTIP41 causes cells to be sensitive to DNA damaging agents, MMS and cisplatin. In addition, cells lacking CaTIP41 show a delay in the recovery from MMS-induced filamentation to yeast form, decreased total PP2A activity and a defect in deactivation of CaRad53 during recovery from DNA damage. We also show that CaTip41 interacts with either CaPph3, CaPsy2 or CaTap42. And deletion of CaTIP41 promotes the interaction between CaTap42 and CaPph3. Finally, C. albicans cells lacking CaPPH3, CaPSY2, CaPSY4 or CaTIP41 and CaTAP42, and the cells carrying the Y33A mutation of CaPSY2, show increased virulence to mice. Therefore, CaPph3 and its regulators play negative roles in regulating the DNA damage-induced filamentation and the virulence in C. albicans.

Yeast Stress and its Response
Speaker
  • Lack of G1/S control in swi6? mutants destabilizes the genome of S. cerevisiae via replication stress-induced DSBs and Rad51-mediated illegitimate recombination
    Speaker
    Adrianna Skoneczna
    Institute of Biochemistry and Biophysics Polish Academy of Sciences
    Poland
    Biography

    Skoneczna A. has completed her PhD at the age of 29 years from Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Poland. She is the professor of Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland. She leads her group in the Laboratory of Mutagenesis and DNA Repair. She has over 30 publications that have been cited over 460 times, and her publication H-index is 12 and has been serving as a reviewer of reputed Journals, as well as in National Science Centre and The National Centre for Research and Development.

    Abstract

    The protein Swi6 in Saccharomyces cerevisiae is a cofactor in two complexes that regulate the transcription of the G1/S transition genes. It also ensures proper oxidative and cell wall stress responses. Our previous study identified SWI6 among genes linked to oversensitivity to radiomimetic zeocin, i.e., genes important for surviving double strand break (DSB) stress. The swi6?/swi6? strain belongs to a very limited group of knock-out strains with high sensitivity to DSBs induced both chemically and by the in vivo overexpression of homing endonucleases. This group also comprises strains lacking XRS2 or RAD52, whose products are crucial in DSB repair. Moreover, one of our previous whole-genome screens also identified the swi6?/swi6? strain as a spontaneous mutator, indicating an important role of Swi6 in maintaining genome stability not only under genotoxic stress but also during unperturbed cell growth. Results we have got recently, showed that: ? swi6? mutants are genetically unstable ? a source of this instability is the replication block leading to DSB formation ? a cellular pathway that enables the repair of DSBs, increasing the chance that swi6? cells will survive, is Rad51-dependent illegitimate recombination, however at high costs, as it is responsible for genome rearrangement leading to division problems, poor growth and increased mortality ? there are the differences between swi6? haploid and swi6?/swi6? diploid yeast cells in the molecular outcomes of replication block, which are not limited to different scenarios of replication block resolution but include different adverse effects of the absence of the Swi6 protein in haploid vs. diploid cells on mutation frequency in the forward mutation assay ? swi6? sensitivity to genotoxic agents might be partially suppressed by the overexpression of SWI4 or PAB1, but only overproduction of the Swi4 protein cures the aberrant DNA content of swi6? mutants. ?

Yeast Epigenetics
Speaker
  • Telomere Position Effect, Epigenetic Conversions and Paused Replication Forks
    Speaker
    Krassimir Yankulov
    University of Guelph
    Canada
    Biography

    K.Yankulov has a PhD from the Imperial Cancer Research Fund (ICRF, London, England, 1994) and did a postdoc at the Amgen Institute (Toronto, Canada). Since 1998 he is a professor at the Department of Molecular and Cellular Biology at the University of Guelph in Canada, Ontario. His main focus of research is on epigenetics in yeast. He has published over 40 publications that have been cited over 2000 times. He is serving as an editorial board member of Frontiers in Genetics and of PLoS One.

    Abstract

    The transmission of epigenetic marks on histones and DNA is an integral part of eukaryotic DNA replication. This transmission culminates in the reconstitution of pre-existing chromatin structures or, alternatively, in an epigenetic conversion of the replicated locus. The subtelomeric genes of S.cerevsiae can be active or “silenced” and infrequently alternated between these two states. This phenomenon is referred to as Telomere Position Effect (TPE). The active or silenced states are determined by chromatin structures, which resemble euchromatin and heterochromatin in metazoans. We have a good understanding of the processes that establish and maintain these chromatin structures, but have very superficial understanding of the processes that lead to a conversion of the epigenetic state of these genes. Recently we have developed an assay for the quantitative assessment of the frequency of epigenetic conversions at the telomeres of S.cerevisiae. We have documented that the destruction of Chromatin Assembly Factor-1 (CAF-1) or the helicase RRM3 substantially reduce the frequency of conversions. CAF-I is a histone chaperone, which reassembles nucleosomes after the passage of the replication forks. RRM3 encodes a DNA helicase that helps the resumption of replication of paused replication forks. Of note, subtelomeric DNA contains multiple RRM3-dependent replication pausing sites. Current models suggest that both Rrm3p and CAF-1 are recruited to replication forks via an interaction with the Proliferating Cell Nuclear Antigen (PCNA, POL30) and that this interaction is regulated by the DBF4-Dependent Kinase, DDK. In this presentation we propose to use TPE as model for replication-coupled epigenetic conversions. We will present our recent studies on the role of two kinases that phosphorylate (CDK and DDK) on the stability and activity of CAF-I.

Day 2

KEYNOTE SPEAKERS
  • Role for lipid droplet biogenesis and microlipophagy in adaptation to lipid imbalance in yeast and in a mouse model for human disease

    Columbia University
    USA
    Biography

    Liza Pon studied mitochondrial function in steroid hormone biosynthesis as a predoctoral student in the laboratory of N.R. Orme-Johnson at Tufts University (1982-1987). As an NRSA Postdoctoral Fellow with Gottfried Schatz at the University of Basel, she studied protein import into mitochondria (1987-1990). Dr. Pon established her own laboratory in 1990 at Columbia University, where she is currently Professor of Pathology and Cell Biology and the Institute of Human Nutrition, and Director of the Confocal and Specialized Microscopy Shared Resource. The focal point of her research is organelle quality control, interaction of mitochondria with the cytoskeleton and other organelles, and how these processes affect cellular fitness and lifespan.

    Abstract

    The immediate responses to inhibition of phosphatidylcholine (PC) biosynthesis in yeast are altered phospholipid levels, slow growth, and defects in the morphology and localization of ER and mitochondria. With chronic lipid imbalance, yeast adapt. We find that lipid droplet (LD) biogenesis is up-regulated in yeast undergoing lipid imbalance and is required for adaptation to lipid imbalance. We confirmed that the Unfolded Protein Response, a stress response pathway that is activated by accumulation of unfolded ER proteins, is activated by this lipid stress. We also find that LDs form at ER aggregates, contain polyubiquitinated proteins and an ER chaperone, and are degraded in the vacuole by a process resembling microautophagy. This process, microlipophagy, is required for restoration of organelle morphology and cell growth during adaptation to lipid stress. Microlipophagy does not require a core macroautophagy gene, ATG7, but does requires ESCRT components. It also requires a newly identified class E VPS protein that localizes to ER and is up-regulated by lipid imbalance. In complementary studies, we detect elevated lipid droplet biogenesis, ER stress, and defects in ER proteins that are essential for excitation contraction coupling in a mouse model for a congenital muscular dystrophy produced by defects in PC biosynthesis. Using super-resolution microscopy, we find that unfolded ER proteins are associated with lipid droplets. Thus, the ER proteostasis pathway that we identified in yeast occurs in mammalian cells and may contribute to protein quality control in human disease.

  • The Yeast Plasmid: A Hitchhiker on Chromosomes

    University of Texas at Austin
    USA
    Biography

    Dr. Jayaram's research is focused on the Saccharomyces cerevisiae plasmid 2-micron circle—a small, high-copy extrachromosomal selfish DNA element with chromosome-like stability. Plasmid persistence is accomplished by a deceptively simple partitioning system consisting of two plasmid-coded proteins and a cis-acting partitioning locus. The partitioning system promotes the tethering of plasmid sisters formed by replication to sister chromatids, and 1:1 plasmid segregation by a hitchhiking mechanism. Copy number maintenance utilizes DNA amplification promoted by the plasmid-coded Flp site-specific recombinase. Amplification is initiated by a replication-coupled DNA inversion reaction. Plasmid gene expression circuitry is fine-tuned for prompt amplification response when needed, without the risk of runaway increase in copy number. Our research interests span mechanisms of (a) DNA rearrangements mediated by Flp and other site-specific recombinases, (b) chromosome-coupled plasmid segregation, and (c) in vivo regulation of Flp levels/activity to prevent inappropriate plasmid amplification. In summary, we wish to unveil the interplay of plasmid- and host-encoded mechanisms that promote their nearly conflict-free coexistence over evolutionary times.

    Abstract

    The native 2-micron plasmid of yeast is remarkable for its nearly chromosome-like stability. This selfish DNA element is optimized for its maintenance at an average copy number of 40-60 molecules per cell nucleus. A plasmid coded partitioning system, comprised of two partitioning proteins and a cis-acting partitioning locus is responsible ensuring the equal or nearly equal segregation of replicated plasmid copies into mother and daughter nuclei. Cumulative results from a variety of genetic, cell biological and biochemical experiments suggest that the partitioning proteins promote the physical association of plasmid molecules to yeast chromosomes. This chromosome tethering is reminiscent of a similar strategy used by the episomes of mammalian gammaherpes and papilloma viruses for propagation in infected cells during long-term latency. Our analyses using fluorescence-tagged single-copy derivatives of the 2-micron plasmid suggest that plasmid sisters formed by replication tether to sister chromatids in a symmetric fashion, thus elevating the plasmid to nearly chromosome status in 1:1 segregation. We are currently mapping potential plasmid-localizing sites on chromosomes using genome-wide approaches.

  • Intraspecific diversity of recombination in S. cerevisiae

    Univ. Paris Sud Université Paris-Saclay
    France
    Biography

    Matthieu Falque has completed his PhD at the age of 26 years from Toulouse University, and postdoctoral fellowships at Montpellier, Wageningen, and Lille. He is Senior Scientist at INRA, Gif-sur-yvette and head of the shared Molecular Biology Facility of the GQE-Le Moulon laboratory. He has published more than 50 papers in international journals or books.

    Abstract

    Allelic recombination due to meiotic crossovers is a major driver of genome evolution, as well as a key player for the selection of high-performing genotypes in economically important species. To get more insights into crossover regulation, we developed a high-throughput method to measure recombination rate and crossover interference in 26 S. cerevisiae strains representing a large part of the diversity of the species. Fifteen intervals were monitored, covering chromosomes VI and XI entirely, and part of chromosome I. Average recombination rates and recombination landscapes varied significantly across strains, and some regions showed up to 9.5-fold variation. We observed interference which varied across strains and was positively correlated with crossover number. Recombination rate was strongly and negatively correlated with whole-genome sequence divergence between homologs, but less so when using solely the sequences of the intervals probed for recombination, and even less so when using the sequences in the DSB rich regions within these intervals, indicating that the negative correlations are not explained by cis-effects only. Finally, to investigate the genetic architecture of crossover rate, we built an incomplete diallel design from five parental strains, and measured recombination in one region of chromosome XI for 10 different hybrids. The results suggest that recombination rate across hybrids may be mainly controlled by the level of sequence divergence between parental strains and by inbreeding effects, while additive effects of parental alleles were hardly significant. These results open the way to a better understanding of the genetic control of crossover formation, as well as building more efficient designs for yeast selection in industrial applications.

  • Evolutionary Diversification of Paralogous Genes in the Yeast Saccharomyces cerevisiae: Its Physiological Role

    CEO & Founder @ Regenerage Medicine
    Mexico
    Biography

    Dra. Maria Alicia González Manjarrez is a Biologist from the Faculty of Sciences of the Universidad Nacional Autónoma de México (UNAM). She obtained her Master and PhD Degrees in the UNAM Biomedical Research Program. She is a Senior Researcher of the Instituto de Fisiología Celular LEVEL 3 of the National System of Researchers (Sistema Nacional de Investigadores (SNI)). Her reasearch Group has been involved in the study of the functional diversification of paralogous genes and its evolutionary implications in the yeast Saccharomyces cerevisiae. Dr. González has published 53 papers in reputed journals and 10 book chapters, taught numerous courses on Genetics, Biochemistry and Molecular Biology at UNAM. She has directed 17 Master Degree Thesis and 16 PhD Thesis. She has organized 10 workshops for Latin-American students on various subjects propitiating the teaching and acquisition of leading techniques and approaches in molecular biology. She was founder of the Branch of Fungal Molecular and Cell Biology of the Mexican Society of Biochemistry. Dra. González was President of the Mexican Society of Biochemistry from 2012-2015. She is the Regional Coordinator of the Latin- American Network on Biology and was member of the Scientific Board of the UNESCO International Basic Sciences Program from 2009-2014. From 2010 to 2017, she was been Head of the Biochemistry and Structural Biology Department of the Instituto de Fisiología Celular, UNAM.

    Abstract

    For many years, it was accepted that the Saccharomyces cerevisiae (S. cerevisiae) lineage arose from a Whole Genome Duplication (WGD), making this yeast an interesting model to study diversification of paralogous genes. Recently, a phylogenetic study found compelling evidence indicating that S. cerevisiae lineage arose from an interspecies hybridization between one strain related to the Kluyveromyces, Lachancea and Eremothecium (KLE) clade and another one related to Zygosaccharomyces rouxii and Torulaspora delbrueckii (ZT). Although whether the hybrid was the result of the fusion of two diploid cells or two haploid cells that underwent a WGD, is still an open question, both scenarios result in the formation of an allotetraploid with two copies of every gene. After the allotetraploid was formed, intragenic recombinations, full gene conversion, differential gene loss and selection pressures shaped S. cerevisiae genome to the one we observe today, harboring conserved blocks of duplicated genes. Retained duplicate genes (paralogs) can simply provide increased dosage of the same protein, or may go through a process of subfunctionalization or neofunctionalization, in which both copies of the gene lose a subset of their ancestral functions, while acquiring new properties. S. cerevisiae has been used as a model organism to analyze gene duplication dynamics and the functional fates of duplicated genes. In this conference I will present and discuss functional diversification pathways of three paralogous gene pairs, whose products are involved in amino acid metabolism and whose subsubfunctionalization led to the separation and specialization of the ancestral function between the two duplicated genes. Examples of the subfunctionalization of paralogous pairs which was been achieved through: i) modifications of the coding sequence leading to paralogous proteins with particular kinetic properties (GDH1/GDH3), ii) modifications of the regulatory region determining differential expression of each gene copy BAT1/BAT2 leading to the specialized functions of Bat1 and Bat2 encoded transaminases, and iii) selective organization of homo or hetero-oligomeric isozymes with peculiar biochemical properties (LEU4/LEU9), will be presented and the functional repercussion of diversification will be amply discussed.

Yeast Physiology
Speaker
  • poster session
    Specific synthesis of trehalose and polyols are protective factors against environmental stress in Candida albicans
    Speaker
    J.C. Argüelles
    Universidad de Murcia
    Spain
    Biography

    J.C. Argüelles has completed his Ph.D. in Biology in 1987 at the University of Murcia and postdoctoral studies from Institute of Biomedicine (CSIC, Madrid, Spain) and from the Lab. of Molecular Cellbiologie at the Catholic University of Leuven (Belgium). He is currently Professor of Microbiology and has published more than 50 papers in reputed journals and has been serving as an editorial board member. Furthermore, he is also engaged in the social and humanistic features of Science, has published two books on scientific historiography, has participated on forums on the dissemination of Science and is a writer of popular science articles in some leading newspapers.

    Abstract

    Candida albicans still remains the most prevalent fungal pathogen of humans. The MAP-kinase HOG1 pathway plays an essential role in the pathobiology of this opportunistic yeast, including the colonization of the gastrointestinal tract in mouse or the defensive response against several environmental injuries. The latter encompasses mechanisms to face both oxidative and osmotic stress treatments. Here we show that one of the main components of this defensive response consists of the intracellular protective accumulation of the non-reducing disaccharide trehalose and two polyols, glycerol and D-arabitol, an accumulation that occurs in a stress-specific dependent manner. Thus, oxidative exposures promoted a marked increase in both trehalose and D-arabitol in the wild-type strain, RM-100 (and several standard genetic backgrounds), whereas the glycerol content remained virtually unaffected with respect to basal (untreated) levels. In contrast, osmotic challenges induced the significant storage of glycerol accompanied by minor changes, or even a slight drop, in the intracellular content of trehalose and D-arabitol. We examined the hypothetical role in this process of the MAP kinase Hog1, which regulates the protective responses in C. albicans against both oxidative and osmotic stress. Interestingly, unlike glycerol synthesis, the stress-induced trehalose accumulation was always Hog1-independent, whereas the ability to synthesize D-arabitol was only partially dependent on a functional Hog1 pathway, at least under our experimental conditions.

Cellular Ageing
Speaker
  • Study on Yeast Lifespan for Aging- and Calorie Restriction- related Genes
    Speaker
    Hae Young Chung
    Pusan National University, South Korea
    South Korea
    Biography

    Hae Young Chung has completed his Ph.D. at the age of 30 years from Toyama University and postdoctoral study from University of Texas Health Science Center at San Antonio. He is the director of Molecular Inflammation Research Center for Aging Intervention. He has published more than 400 papers in reputed journals and has been serving as an editorial board member of AGE.

    Abstract

    Aging is a physiological process caused by time-dependent, progressive changes in multiple biological systems, which induces the increased incidence of age-related diseases. Among anti-aging strategies, calorie restriction (CR) is a widely accepted anti-aging paradigm. Recently, high-throughput technologies are applied to find aging/CR-associated genes. Given that high-throughput methods generate huge amounts of data, it is necessary to study how these CR-related bio-molecules work, interact, and exert their influence in terms of systemic view. Here, we propose database of aging and calorie restriction (CR) related genes. We first screened mouse genes that are related to both aging and CR. We then investigated the orthologs of the common genes in yeast and used these results to confirm and measure functions and life-spans using yeast knockout strains. We suggested a systematic framework and database for further understanding of aging process.

Yeast Stress and its Response
Speaker
  • poster session
    The effects of nanosecond pulsed electric fields on Saccharomyces cerevisiae cells
    Speaker
    Povilas Šimonis
    Center for Physical Sciences and Technology
    Lithuania
    Biography

    Povilas Šimonis has finished master studies Biochemistry (Vilnius University) and started his Chemistry PhD (Center for Physical Sciences and Technology) in 2016. During his scientific career he participated in various schools related to application of pulsed electric fields including: EBTT – international scientific workshop and postgraduate course, school on applications of Pulsed Electric Fields for food processing. He is a member of ISEBTT (International Society of Electroporation – Based Technologies and Treatments). Presented his working results in more than 10 local and international conferences. Currently his scientific data is already published in Bioelectrochemistry Journal.

    Abstract

    Saccharomyces cerevisiae is one of the most well-studied and understood eukaryotic organisms. The studies of yeast cell allow reconstitution of possible molecular mechanisms of various abiotic effects. Pulsed electric field has been one of the most intensively investigated abiotic effects on biological tissues and cell suspensions for a past decade. It has been previously shown that a nanosecond pulsed electric field (nsPEF) permeabilize the plasma membrane, alter gene expression, cause phosphatidylserine translocation, affect the distribution of intracellular ions and even lead to the death of mammalian cells. There is still a lack of sufficient data related to the effects of nsPEF on yeast cells yet. In our study we analyzed the effects of square shaped electrical pulses of different duration (?= 10-90 ns) and pulse number (pn= 1-5) with electric field strength (E) up to 220 kV/cm and showed that nanosecond pulses can induce the cell death, which in turn is dependent on the electric field pulse parameters and increase with the rise in E, ? and pulse number. Exposure of yeast cells to nsPEFs was accompanied by metacaspase activation, membrane permeability to propidium iodide and the externalization of phosphatidylserine. Furthermore, the investigation of yeast cells permeabilization to tetraphenylphosphonium ions (TPP+), which was induced by high power nanosecond duration electrical pulses, had demonstrated the following features: (i) The study of TPP+ ions absorption rate by yeast cells is an effective method for detection of short duration electric pulse influence on yeast cell wall properties; (ii) Shortening of the electric pulse duration makes it possible to achieve more homogeneous electrical treatment of yeast cell clusters and by this way to increase the effectiveness of single cell permeabilization; (iii) The significant acceleration of TPP+ ions absorption rate (up to 65 times) can be achieved without any influence on the vitality of the cells. We conclude that square shaped electric field pulses with nanosecond durations induce wide variety of effects including caspase-dependent apoptosis, oxidative stress, cell wall

Genetics and Molecular Biology
Speaker
  • Hydroxyurea arrests Saccharomyces cerevisiae cells in G1/early S-phase of the cell cycle and limits rRNA synthesis
    Speaker
    Alexia Muguet
    University of Sherbrooke
    Canada
    Biography

    Alexia Muguet has a master in marine ecology from the Université Pierre et Marie Curie - Paris VI (France) (2014) and a master in microbiology from the Université de Bretagne Occidentale (France) (2015). She previously worked on microalgae ecophysiology before starting studying microorganisms at molecular level. During her master internship, she worked on the replication helicase MCM from Pyrococcus abyssi, an Euryarchaeota. As PhD student at Université de Sherbrooke (Québec), she is studying DNA repair mechanisms and chromatin on Saccharomyces cerevisiae. Her main work is analyzing the rRNA gene proteome linked to UV radiation and Nucleotide Excision Repair to highlight proteins involved in chromatin repair-dependent modifications. Alexia participated in two published papers and in in-redaction one.

    Abstract

    The chemotherapeutic agent Hydroxyurea (HU) inhibits the ribonucleotide reductase preventing the synthesis of dNTPs. Consequently, DNA replication is inhibited and cells arrest in G1/early S-phase of the cell cycle. Additionally, yeast exposed to the natural pheromone ?-factor arrest cell division in G1. Cell growth hinges on the tightly regulated processes of ribosome biogenesis and rRNA synthesis. Thus, expression of rRNA genes and rRNA processing were analyzed in cell cycle arrested cells by both the chemotherapeutic agent HU and the pheromone ?-factor. Chromatin endogenous cleavage, chromatin immuno-precipitation, chromatin spreading and Northern blotting were employed to investigate the effect of HU on the expression of rRNA genes and rRNA synthesis. The results indicate that in yeast arrested by HU the overall number of active promoters remains unchanged, and that rRNA genes chromatin stay poised for transcription. However, distribution of RNAPI on individual rRNA gene and rRNA processing are disturbed, lowering rRNA synthesis. Conversely, in ?-factor arrested cells rRNA transcription was not affected. These results point out a hitherto unnoticed cellular response to HU that might participate in the inhibition of cell division. NSERC and Ministère des Relations Internationales du Québec (to AC), Bavarian State Chancellery (Bayerisch-Franzosisches Hochschulzentrum, to JG).

Fermentation and Yeast Biotechnology
Speaker
  • Poster session
    1) Identification of Some Probiotic Properties of Yeasts isolated From Turkish Cheeses 2)Evaluation of Some Probiotic Properties of Yeasts isolated From Turkish Cheeses
    Speaker
    Abudureyimu MAIHEBUBAI
    Gazi University
    Turkey
    Abstract

    1) Identification of Some Probiotic Properties of Yeasts isolated From Turkish Cheeses Yeasts not only play an important role in flavor and texture development during the production of cheese, also have shown probiotic effects on human health. In this study, four yeast isolates from Turkish cheeses were characterized to species level by phenotypic criteria using API ID 32 microbial identification kits and 18S rRNA sequence analysis. Three of them identified as Pichia kudriavzeii (M16, M17, M57), while another one was Kluyveromyces marxianus (M29). Yeast strains were tested for their ability to survive in simulated gastric juice and intestinal environment. The survival of all tested yeasts was 88.9-145% after 4 hours of incubation in media with the addition of 1g/L pancreatin and 46.3-80.4% after 3 hours of incubation in media with the addition of 3g/L pepsin (pH 1.5). All yeast strains were able to assimilate cholesterol in the range of 9,3-28,8% over a 48 h incubation. The DPPH radical scavenging activity of yeast strains was ranging between 75.1-80.5%. According to these results, the yeast strains could be considered as co-culture or probiotic in the preparation of fermented dairy products for contributing to the quality and health related functional properties of products. 2) Evaluation of Some Probiotic Properties of Yeasts isolated From Turkish Cheeses The possible beneficial properties of dairy foods and associated microorganisms for both human and animal health are increasingly investigated. In this study, three Pichia kudriavzeii (M16, M17, M57) and one Kluyveromyces marxianus (M29) strains isolated from Turkish cheeses were evaluated for some functional properties relevant to their use as probiotic. All strains were able to grow under low acid condition (pH 3) and survived well (61.4-100%) in the presence of conjugated bile salts (0.3%) after 48h of incubation, while producing exopolysaccharide (EPS) ranging between 55.3-130.7 mg/L. All yeast strains presented high auto-aggregation ability in the range of 70.6-88.7%. All strains also showed higher hydrophobic activities in acidic chloroform and toluene solvents compared with the neutral p-xylane solvent and basic ethyl acetate solvent. Only P. kudriavzeii M57 showed inhibitory activities on Bacillus cereus RSKK 863 (11.7mm) and Pseudomonas aeruginosa ATCC 27853 (11.9mm). In conclusion, the presented results indicate that both Pichia kudriavzeii and Kluyveromyces marxianus strains isolated from cheeses could be regarded as appropriate candidate for new probiotic yeast strains, they could be used as adjunct cultures for contributing to the quality and health related functional properties of dairy products.

  • Reducing ground water consumption in Pakistani distillery through very high gravity technology
    Speaker
    Muhammad Arshad
    University of Veterinary and Animal Sciences
    Pakistan
    Biography

    Abstract

    Very high gravity technology (VHG) was implemented on industrial scale fermenters to study the reduction in fresh water consumption in the process as well as ethanol and by products formation during molasses fermentation. Different brixº 32, 36 and 40 with aeration rates 0.00, 0.20, 0.40, and 0.60 vvm has been applied. The maximum ethanol production was 12.2% (v/v) at 40º brix with 0.2 vvm aeration. Byproducts have the increasing trend with the brixº but aeration rate 0.2 vvm was found to be optimum for byproduct formation throughout the study. The high ethanol % attained had eased the distillation process and steam consumption reduced significantly. More over water consumption was reduced by 35% decreasing the stillage volume. Reduction in steam consumption decreases the overall water utilization by improving the economics of industrial ethanol production process significantly. Decrease in stillage volume is helpful in combating this environmental pollutant efficiently.

Bioenergy and Biofuels
Speaker
  • Bioengineering of Yeast Cell for biodiesel Production
    Speaker
    Priya Kumari
    International Centre for Genetic Engineering and Biotechnology (ICGEB)
    India
    Biography

    Abstract

    Due to increased oil demand, depleting fossil fuels and greenhouse gas emissions, biofuels production are getting much attention. The fatty acid based biofuels (fatty acids ethyl ester/biodiesel, fatty alcohol, etc.) produced from microbial cells have emerged as ideal alternatives to fossil oils, with significant pluses over plant, animal and algae oils. Saccharomyces cerevisiae is a most studied industrial model microorganism and also its fatty acid production ability has been increased by metabolic engineering approach. But still the cost of the process limits its industrial production therefore, more research is required. Here, we are addressing this issue by sequential metabolic engineering approach. In order to synthesize biodiesel in yeast cells, we integrated wax ester synthase (WS2) gene from Marinobacter hydrocarbonoclasticus into its genome. The genetic engineering approaches have focused on high-level biodiesel production by rewiring metabolism pathways to upsurge carbon flux towards fatty acid CoA synthesis, by increasing the cofactor supply, and disrupting the degradation pathway.

Yeast Bioremediation
Speaker
  • Cd+2 Resistance Mechanism in Candida tropiclis 3Aer isolated from Industrial Effluents
    Speaker
    Abdul Rehman
    University of the Punjab
    Pakistan
    Biography

    Abstract

    Present investigation is elucidating the bioremediation potential and cadmium-induced cellular response with its molecular basis in Candida tropicalis 3Aer. Spectroscopic analysis clearly illustrated the involvement of yeast cell wall components in biosorption whereas bioaccumulation was confirmed by TEM, SEM and EDX scrutiny. TEM images divulged extracellular as well as cytoplasmic and vacuolar cadmium nanoparticle formation, further validated by presence of ycf1 gene and increased biosynthesis of GSH under cadmium stress. Transcriptomic and proteomic approaches have rarely been applied to study change in cell architecture under environmental stress conditions, but this study is unveiling the altered expression of proteins and genes in C. tropicalis 3Aer under cadmium stress in concentration and time dependent manner, respectively. Fourteen proteins exhibited differential expression and found involve in cellular redox homeostasis, nitrogen metabolism, nucleotide biosynthesis and carbohydrate catabolism. Interestingly, C. tropicalis 3Aer is additionally equipped with nitrile hydratase enzyme, rarely been reported in yeast and thus have potential to remove nitriles (extremely toxic compounds) from environment. Cd+2 toxicity not only caused growth stasis but also upregulated the cysteine biosynthesis, protein folding and cytoplasmic detoxification response elements.

Mail us at

Yeast Congress 2018,Canada
yeast@alliedconferences.org
Yeast Congress 2018,Canada
yeastcongress@alliedmeetings.com
More details about sponsorship:sponsors@alliedacademies.com

Terms and Conditions

Responsibility

Delegates are personally responsible for their belongings at the venue. The Organizers will not be held responsible for any stolen or missing items belonging to Delegates, Speakers or Attendees; due to any reason whatsoever.

Insurance

Registration fees do not include insurance of any kind.

Transportation

Please note that any (or) all transportation and parking is the responsibility of the registrant.

Press/Media

Press permission must be obtained from Conferences Organizing Committee prior to the event. The press will not quote speakers or delegates unless they have obtained their approval in writing. Allied Academies is an objective third-party nonprofit organization. This conference is not associated with any commercial meeting company.

Requesting an Invitation Letter

For security purposes, letter of invitation will be sent only to those individuals who had registered for the conference. Once your registration is complete, please contact yeastcongress@alliedmeetings.com  to request a personalized letter of invitation.

Cancellation Policy

If Allied Academies cancels this event for any reason, you will receive a credit for 100% of the registration fee paid. You may use this credit for another Allied Academies event which must occur within one year from the date of cancellation.

Postponement

If Allied Academies postpones an event for any reason and you are unable or unwilling to attend on rescheduled dates, you will receive a credit for 100% of the registration fee paid. You may use this credit for another Allied Academies event which must occur within one year from the date of postponement.

Transfer of registration

All fully paid registrations are transferable to other persons from the same organization if registered person is unable to attend the event. Transfers must be made by the registered person in writing to yeastcongress@alliedmeetings.com. Details must be included the full name of replacement person, their title, contact phone number and email address. All other registration details will be assigned to the new person unless otherwise specified.

Registration can be transferred to one conference to another conference of Allied Academies if the person is unable to attend one of the conferences.

However, Registration cannot be transferred if it is intimated within 14 days of the respective conference.

The transferred registrations will not be eligible for Refund.

Visa Information

Keeping in view of increased security measures, we would like to request all the participants to apply for Visa as soon as possible.

Allied Academies will not directly contact embassies and consulates on behalf of visa applicants. All delegates or invitees should apply for Business Visa only.

Important note for failed visa applications: Visa issues cannot come under the consideration of cancellation policy of Allied Academies including the inability to obtain a visa.

Refund Policy:

If the registrant is unable to attend and is not in a position to transfer his/her participation to another person or event, then the following refund arrangements apply:

Keeping in view of advance payments towards Venue, Printing, Shipping, Hotels and other overheads, we had to keep Refund Policy is as following slabs-

  • Before 60 days of the conference: Eligible for Full Refund less $100 Service Fee
  • Within 60-30 days of Conference: Eligible for 50% of payment Refund
  • Within 30 days of Conference: Not eligible for Refund
  • E-Poster Payments will not be refunded.

Accommodation Cancellation Policy:

Accommodation Providers (Hotels) have their own cancellation policies, and they generally apply when cancellations are made less than 30 days prior to arrival. Please contact us as soon as possible, if you wish to cancel or amend your accommodation. Allied Academies will advise the cancellation policy of your accommodation provider, prior to canceling or amending your booking, to ensure you are fully aware of any non-refundable deposits.

Highlights from last year's Convention

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