A hasadó élesztőgomba sep génjeinek funkcionális analízise = Functional analysis of the fission yeast sep genes

Az egysejtes Schizosaccharomyces pombe ideális modellszervezet az eukarióta sejtciklus tanulmányozásához. A debreceni laboratórium több mint 30 sejtciklus-gént identifikált ebben a szervezetben. A jelenlegi projektben öt sep gén molekuláris biológiai vizsgálatát végezték el. Korábbi eredményeik alapján már tudták, hogy ezek a gének többféle funkciót is ellátnak a sejtben, beleértve a citokinezist követő sejtszeparáció szabályozását is. A mostani pályázat keretében elért eredmények bebizonyították, hogy a sejtszeparációhoz szükséges fehérjéket kódoló gének kulcsfontosságú regulátora a Sep1p transzkripciós faktor. Feladatát az ace2 szabályázásán keresztül látja el. Az ace2 is transzkripciós faktort kódol. A sep10, sep11 és sep15 gének termékei a Mediator-komplex alegységeiként nagyobb géncsoportok koaktivátorai. Részt vesznek az ace2 által szabályozott gének regulációjában is. A SAGA alegységet kódoló sep9 is része a komplex szabályozó mechanizmusnak. | The unicellular Schizosaccharomyces pombe is an ideal model for the investigation of the eukaryotic cell cycle. The Debrecen laboratory has identified over 30 cell cycle genes in this organism. The current project was focused on the molecular biological analysis of five sep genes. Previous work done in Debrecen has indicated that these sep genes perform multiple functions including the regulation of cell separation that follows cytokinesis. The results obtained during the project period demonstrated that the transcription factor Sep1p is a key regulator of the genes that code for proteins necessary for the separation process. It exerts its function through the regulation of ace2, a gene that also codes for a transcription factor. The products of the genes sep10, sep11 and sep15 are subunits of the Mediator complex and act as coactivators of larger subsets of other genes, including those controlled by ace2. sep9 encodes a SAGA subunit also involved in the complex regulatory mechanism

Assembly of Schizosaccharomyces cryophilus chromosomes and their comparative genomic analyses revealed principles of genome evolution of the haploid fission yeasts

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Commercial strain-derived clinical Saccharomyces cerevisiae can evolve new phenotypes without higher pathogenicity

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Commercial strain-derived clinical Saccharomyces cerevisiae can evolve new phenotypes without higher pathogenicity

Scope: Saccharomyces cerevisiae is one of the most important microbes in food industry, but there is growing evidence on its potential pathogenicity as well. Its status as a member of human mycobiome is still not fully understood.Methods and results: In this study, we characterise clinical S. cerevisiae isolates from Hungarian hospitals along with commercial baking and probiotic strains, and determine their phenotypic parameters, virulence factors, interactions with human macrophages, and pathogenicity. Four of the clinical isolates could be traced back to commercial strains based on genetic fingerprinting. Our observations indicate that the commercial-derived clinical isolates have evolved new phenotypes and show similar, or in two cases, significantly decreased pathogenicity. Furthermore, immunological experiments revealed that the variability in human primary macrophage activation after co-incubation with yeasts is largely donor- and not isolate-dependent.Conclusion: Isolates in this study offer an interesting insight into the potential microevolution of probiotic and food strains in human hosts. These commensal yeasts display various changes in their phenotypes, indicating that the colonization of the host does not necessarily impose a selective pressure towards higher virulence/pathogenicity

Endogenous single-strand DNA breaks at RNA polymerase II promoters in <i>Saccharomyces cerevisiae</i>

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Molecular Genetic Analysis of a Fertile Interspecific Hybrid Accharomyces Cerevisiae and Saccharomyces Uvarum and its Progenies

Napjainkban a mustok szárított élesztő-kultúrákkal („starter”) való beoltásával a fermentáció felgyorsítását, az erjedési folyamatok ellenőrizhetővé tételét és befolyásolását érte el a biotechnológia. A különböző starter-élesztőknek stabil genetikai állománnyal kell rendelkezniük, hogy alkalmazásuk során a bor minőségét befolyásoló jellegeik ne változzanak és ugyanazt a megbízható íz-, aroma,- és zamatminőséget produkálják. A borászatban leggyakrabban alkalmazott startereket a Saccharomyces cerevisiae és S. uvarum élesztőfajok változataiból (törzseiből) állítják elő. The presence of the interspecific hybrids in nature is a very interesting phenomenon, because, with some rare exceptions, they are sterile: the developed combined parenthal genetical materia is handed down into only one generation. But, besides being a „luxury staff” of nature, the formation of the interspecific hybrids could lead to new strains arising, during some thousands years. These kinds of yeast hybrids came into the spotlight in also the modern winery’s area (Zambonelli et al., 1997; Masneuf at al., 2003). Their biotechnological importance is in the creation of a better fermenthor hybrid strain, which has stable genetical materia, by crossing selected, good qualited yeast strains, combining their advantaged properties (Caridi et al., 2002)

Synthetic two-species allodiploid and three-species allotetraploid Saccharomyces hybrids with euploid (complete) parental subgenomes

Abstract Combination of the genomes of Saccharomyces species has great potential for the construction of new industrial strains as well as for the study of the process of speciation. However, these species are reproductively isolated by a double sterility barrier. The first barrier is mainly due to the failure of the chromosomes to pair in allodiploid meiosis. The second barrier ensures that the hybrid remains sterile even after genome duplication, an event that can restore fertility in plant interspecies hybrids. The latter is attributable to the autodiploidisation of the allotetraploid meiosis that results in sterile allodiploid spores (return to the first barrier). Occasionally, mating-competent alloaneuploid spores arise by malsegregation of MAT-carrying chromosomes. These can mate with cells of a third species resulting in aneuploid zygotes having at least one incomplete subgenome. Here we report on the construction of euploid three-species hybrids by making use of “rare mating” between a sterile S. kudriavzevii x S. uvarum allodiploid hybrid and a diploid S. cerevisiae strain. The hybrids have allotetraploid 2nScnSk nSu genomes consisting of complete sets of parental chromosomes. This is the first report on the production of euploid three-species Saccharomyces hybrids by natural mating, without genetic manipulation. The hybrids provide possibilities for studying the interactions of three allospecific genomes and their orthologous genes present in the same cell