The ability of yeast cells to adhere to solid surfaces or even penetrate semi-solid surfaces and form multicellular biofilms are critical factors in infection. This study examines the relationship between cell adhesion capability and the ability to create spatially organized biofilms in selected Saccharomyces cerevisiae strains, including clinical isolates, and five Candida species (C. albicans, C. glabrata, C. krusei, C. parapsilosis, and C. tropicalis). We assessed cell adhesion to polystyrene surface in four media varying in source of carbon and other nutrients. Using microscopy of vertical cell arrangement profiles within yeast populations grown at the solid-liquid interface, we evaluated their internal organization to determine whether the populations exhibit typical biofilm characteristics, such as the spatial organization of distinct cell types. Results indicate that well adherent S. cerevisiae strains form spatial biofilms with typical internal organization, highlighting strain-specific responses to media composition and supporting the use of natural S. cerevisiae strains for biofilm research. Among Candida species, biofilm formation did not consistently align with adhesion efficiency to plastic; while C. albicans and C. krusei formed spatially structured biofilms on media where they adhered well, C. tropicalis and C. glabrata exhibited efficient adhesion without biofilm structuring. Interestingly, C. parapsilosis formed a structured biofilm despite minimal adhesion. These findings emphasize the role of media composition, particularly components of yeast extract and defined medium for mammalian cell growth RPMI, which differentially impacted adhesion and biofilm formation in S. cerevisiae and C. albicans.

• Klíčová slova
• Adhesion, Biofilm, Microscopy, Spatial structure, Yeast,
• Publikační typ
• časopisecké články MeSH

Cell death is a natural part of the development of multicellular organisms and is central to their physiological and pathological states. However, the existence of regulated cell death in unicellular microorganisms, including eukaryotic and prokaryotic microbes, has been a topic of debate. One reason for the continued debate is the lack of obvious benefit from cell death in the context of a single cell. However, unicellularity is relative, as most of these microbes dwell in communities of varying complexities, often with complicated spatial organization. In these spatially organized microbial communities, such as yeast and bacterial colonies and biofilms growing on solid surfaces, cells differentiate into specialized types, and the whole community often behaves like a simple multicellular organism. As these communities develop and age, cell death appears to offer benefits to the community as a whole. This review explores the potential roles of cell death in spatially organized communities of yeasts and draws analogies to similar communities of bacteria. The natural dying processes in microbial cell communities are only partially understood and may result from suicidal death genes, (self-)sabotage (without death effectors), or from non-autonomous mechanisms driven by interactions with other differentiated cells. We focus on processes occurring during the stratification of yeast colonies, the formation of the extracellular matrix in biofilms, and discuss potential roles of cell death in shaping the organization, differentiation, and overall physiology of these microbial structures.

• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

Single-celled yeasts form spatially structured populations - colonies and biofilms, either alone (single-species biofilms) or in cooperation with other microorganisms (mixed-species biofilms). Within populations, yeast cells develop in a coordinated manner, interact with each other and differentiate into specialized cell subpopulations that can better adapt to changing conditions (e.g. by reprogramming metabolism during nutrient deficiency) or protect the overall population from external influences (e.g. via extracellular matrix). Various omics tools together with specialized techniques for separating differentiated cells and in situ microscopy have revealed important processes and cell interactions in these structures, which are summarized here. Nevertheless, current knowledge is still only a small part of the mosaic of complexity and diversity of the multicellular structures that yeasts form in different environments. Future challenges include the use of integrated multi-omics approaches and a greater emphasis on the analysis of differentiated cell subpopulations with specific functions.

• Klíčová slova
• Biofilms, Cell differentiation, Colonies, Multicellular yeast structures, Regulation, Spatial community structure,
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

Multicellular structures formed by yeasts and other microbes are valuable models for investigating the processes of cell-cell interaction and pattern formation, as well as cell signaling and differentiation. These processes are essential for the organization and development of diverse microbial communities that are important in everyday life. Two major types of multicellular structures are formed by yeast Saccharomyces cerevisiae on semisolid agar. These are colonies formed by laboratory or domesticated strains and structured colony biofilms formed by wild strains. These structures differ in spatiotemporal organization and cellular differentiation. Using state-of-the-art microscopy and mutant analysis, we investigated the distribution of cells within colonies and colony biofilms and the involvement of specific processes therein. We show that prominent differences between colony and biofilm structure are determined during early stages of development and are associated with the different distribution of growing cells. Two distinct cell distribution patterns were identified-the zebra-type and the leopard-type, which are genetically determined. The role of Flo11p in cell adhesion and extracellular matrix production is essential for leopard-type distribution, because FLO11 deletion triggers the switch to zebra-type cell distribution. However, both types of cell organization are independent of cell budding polarity and cell separation as determined using respective mutants.

• Klíčová slova
• Flo11p adhesin, cell adhesion, cell organization, colonies and biofilms, laboratory and wild Saccharomyces cerevisiae strains, structure development, yeast multicellular structures,
• MeSH
• biofilmy * MeSH
• buněčné dělení MeSH
• membránové glykoproteiny genetika   metabolismus   MeSH
• mikrobiální interakce MeSH
• mutace MeSH
• Saccharomyces cerevisiae - proteiny genetika   metabolismus   MeSH
• Saccharomyces cerevisiae cytologie   metabolismus   fyziologie   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• FLO11 protein, S cerevisiae MeSH Prohlížeč
• membránové glykoproteiny MeSH
• Saccharomyces cerevisiae - proteiny MeSH

Saccharomyces cerevisiae is a mainly beneficial yeast, widely used in the food industry. However, there is growing evidence of its potential pathogenicity, leading to fungemia and invasive infections. The medical impact of yeast pathogens depends on formation of biofilms: multicellular structures, protected from the environment. Cell adhesion is a prerequisite of biofilm formation. We investigated the adherence of wild and genetically modified S. cerevisiae strains, formation of solid-liquid interface biofilms and associated regulation. Planktonic and static cells of wild strain BRF adhered and formed biofilms in glucose-free medium. Tup1p and Cyc8p were key positive and negative regulators, respectively. Glucose caused increased Cyc8p levels and blocked cell adhesion. Even low glucose levels, comparable with levels in the blood, allowed biofilm dispersal and release of planktonic cells. Cyc8p could thus modulate cell adhesion in different niches, dependently on environmental glucose level, e.g., high-glucose blood versus low-glucose tissues in host organisms.

• MeSH
• bakteriální adheze MeSH
• biofilmy růst a vývoj   MeSH
• glukosa metabolismus   MeSH
• jaderné proteiny genetika   metabolismus   MeSH
• kultivační média chemie   MeSH
• mutace MeSH
• povrchové vlastnosti MeSH
• regulace genové exprese u hub MeSH
• represorové proteiny genetika   metabolismus   MeSH
• Saccharomyces cerevisiae - proteiny genetika   metabolismus   MeSH
• Saccharomyces cerevisiae genetika   fyziologie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• CYC8 protein, S cerevisiae MeSH Prohlížeč
• glukosa MeSH
• jaderné proteiny MeSH
• kultivační média MeSH
• represorové proteiny MeSH
• Saccharomyces cerevisiae - proteiny MeSH
• TUP1 protein, S cerevisiae MeSH Prohlížeč

Yeasts create multicellular structures of varying complexity, such as more complex colonies and biofilms and less complex flocs, each of which develops via different mechanisms. Colony biofilms originate from one or more cells that, through growth and division, develop a complicated three-dimensional structure consisting of aerial parts, agar-embedded invasive parts and a central cavity, filled with extracellular matrix. In contrast, flocs arise relatively quickly by aggregation of planktonic cells growing in liquid cultures after they reach the appropriate growth phase and/or exhaust nutrients such as glucose. Creation of both types of structures is dependent on the presence of flocculins: Flo11p in the former case and Flo1p in the latter. We recently showed that formation of both types of structures by wild Saccharomyces cerevisiae strain BR-F is regulated via transcription regulators Tup1p and Cyc8p, but in a divergent manner. Biofilm formation is regulated by Cyc8p and Tup1p antagonistically: Cyc8p functions as a repressor of FLO11 gene expression and biofilm formation, whereas Tup1p counteracts the Cyc8p repressor function and positively regulates biofilm formation and Flo11p expression. In addition, Tup1p stabilizes Flo11p probably by repressing a gene coding for a cell wall or extracellular protease that is involved in Flo11p degradation. In contrast, formation of BR-F flocs is co-repressed by the Cyc8p-Tup1p complex. These findings point to different mechanisms involved in yeast multicellularity.

• Klíčová slova
• Adhesion and invasion, Colony biofilm, Cyc8p and Tup1p, Flocculation, Yeast multicellular structures,
• MeSH
• biofilmy MeSH
• buněčná stěna genetika   metabolismus   MeSH
• druhová specificita MeSH
• jaderné proteiny genetika   metabolismus   MeSH
• regulace genové exprese u hub * MeSH
• represorové proteiny genetika   metabolismus   MeSH
• Saccharomyces cerevisiae - proteiny genetika   metabolismus   MeSH
• Saccharomyces cerevisiae klasifikace   genetika   fyziologie   MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• CYC8 protein, S cerevisiae MeSH Prohlížeč
• jaderné proteiny MeSH
• represorové proteiny MeSH
• Saccharomyces cerevisiae - proteiny MeSH
• TUP1 protein, S cerevisiae MeSH Prohlížeč

Yeast biofilms are complex multicellular structures, in which the cells are well protected against drugs and other treatments and thus highly resistant to antifungal therapies. Colony biofilms represent an ideal system for studying molecular mechanisms and regulations involved in development and internal organization of biofilm structure as well as those that are involved in fungal domestication. We have identified here antagonistic functional interactions between transcriptional regulators Cyc8p and Tup1p that modulate the life-style of natural S. cerevisiae strains between biofilm and domesticated mode. Herein, strains with different levels of Cyc8p and Tup1p regulators were constructed, analyzed for processes involved in colony biofilm development and used in the identification of modes of regulation of Flo11p, a key adhesin in biofilm formation. Our data show that Tup1p and Cyc8p regulate biofilm formation in the opposite manner, being positive and negative regulators of colony complexity, cell-cell interaction and adhesion to surfaces. Notably, in-depth analysis of regulation of expression of Flo11p adhesin revealed that Cyc8p itself is the key repressor of FLO11 expression, whereas Tup1p counteracts Cyc8p's repressive function and, in addition, counters Flo11p degradation by an extracellular protease. Interestingly, the opposing actions of Tup1p and Cyc8p concern processes crucial to the biofilm mode of yeast multicellularity, whereas other multicellular processes such as cell flocculation are co-repressed by both regulators. This study provides insight into the mechanisms regulating complexity of the biofilm lifestyle of yeast grown on semisolid surfaces.

• MeSH
• biofilmy * MeSH
• buněčná adheze fyziologie   MeSH
• jaderné proteiny genetika   metabolismus   MeSH
• membránové glykoproteiny genetika   metabolismus   MeSH
• mezibuněčná komunikace fyziologie   MeSH
• regulace genové exprese u hub * MeSH
• represorové proteiny genetika   metabolismus   MeSH
• Saccharomyces cerevisiae - proteiny genetika   metabolismus   MeSH
• Saccharomyces cerevisiae fyziologie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• CYC8 protein, S cerevisiae MeSH Prohlížeč
• FLO11 protein, S cerevisiae MeSH Prohlížeč
• jaderné proteiny MeSH
• membránové glykoproteiny MeSH
• represorové proteiny MeSH
• Saccharomyces cerevisiae - proteiny MeSH
• TUP1 protein, S cerevisiae MeSH Prohlížeč

BACKGROUND: Yeast infections are often connected with formation of biofilms that are extremely difficult to eradicate. An excellent model system for deciphering multifactorial determinants of yeast biofilm development is the colony biofilm, composed of surface ("aerial") and invasive ("root") cells. While surface cells have been partially analyzed before, we know little about invasive root cells. In particular, information on the metabolic, chemical and morphogenetic properties of invasive versus surface cells is lacking. In this study, we used a new strategy to isolate invasive cells from agar and extracellular matrix, and employed it to perform genome wide expression profiling and biochemical analyses of surface and invasive cells. RESULTS: RNA sequencing revealed expression differences in 1245 genes with high statistical significance, indicating large genetically regulated metabolic differences between surface and invasive cells. Functional annotation analyses implicated genes involved in stress defense, peroxisomal fatty acid β-oxidation, autophagy, protein degradation, storage compound metabolism and meiosis as being important in surface cells. In contrast, numerous genes with functions in nutrient transport and diverse synthetic metabolic reactions, including genes involved in ribosome biogenesis, biosynthesis and translation, were found to be important in invasive cells. Variation in gene expression correlated significantly with cell-type specific processes such as autophagy and storage compound accumulation as identified by microscopic and biochemical analyses. Expression profiling also provided indications of cell-specific regulations. Subsequent knockout strain analyses identified Gip2p, a regulatory subunit of type 1 protein phosphatase Glc7p, to be essential for glycogen accumulation in surface cells. CONCLUSIONS: This is the first study reporting genome wide differences between surface and invasive cells of yeast colony biofilms. New findings show that surface and invasive cells display very different physiology, adapting to different conditions in different colony areas and contributing to development and survival of the colony biofilm as a whole. Notably, surface and invasive cells of colony biofilms differ significantly from upper and lower cells of smooth colonies adapted to plentiful laboratory conditions.

• Klíčová slova
• Cell differentiation, Colony biofilms, Invasive cell subpopulation, Regulation of glycogen metabolism, Saccharomyces cerevisiae, Transcriptomics,
• MeSH
• biofilmy * MeSH
• metabolické sítě a dráhy MeSH
• regulace genové exprese u hub * MeSH
• Saccharomyces cerevisiae - proteiny genetika   metabolismus   MeSH
• Saccharomyces cerevisiae genetika   fyziologie   MeSH
• stanovení celkové genové exprese MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• Saccharomyces cerevisiae - proteiny MeSH