Fyziologické změny kmenů Saccharomyces cerevisiae s delecemi v genech pro PDR transportéry

We focused on comparison of the development and behaviour of S. cerevisiae strains overproducing various PDR transporters to those that have genes for some of them deleted. Besides a spectrum of physiological parameters, we analysed also expression changes of selected genes and measured reduced cytochrome spectra of these strains to find out the state of their respiratio

Long Noncoding RNAs in Yeast Cells and Differentiated Subpopulations of Yeast Colonies and Biofilms

We summarize current knowledge regarding regulatory functions of long noncoding RNAs (lncRNAs) in yeast, with emphasis on lncRNAs identified recently in yeast colonies and biofilms. Potential regulatory functions of these lncRNAs in differentiated cells of domesticated colonies adapted to plentiful conditions versus yeast colony biofilms are discussed. We show that specific cell types differ in their complements of lncRNA, that this complement changes over time in differentiating upper cells, and that these lncRNAs target diverse functional categories of genes in different cell subpopulations and specific colony types

Cyc8p and Tup1p transcription regulators antagonistically regulate Flo11p expression and complexity of yeast colony biofilms

<div><p>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 <i>S</i>. <i>cerevisiae</i> 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 <i>FLO11</i> 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.</p></div

The transport of carboxylic acids and important role of the Jen1p transporter during the development of yeast colonies

On solid substrates, yeast colonies pass through distinct developmental phases characterized by the changes in pH of their surroundings from acidic to nearly alkaline and vice versa. At the beginning of the alkali phase colonies start to produce ammonia, which functions as a quorum-sensing molecule inducing the reprogramming of cell metabolism. Such reprogramming includes, among others, the activation of several plasma membrane transporters and is connected with colony differentiation. In the present study, we show that colony cells can use two transport mechanisms to import lactic acid: a 'saturable' component of the transport, which requires the presence of a functional Jen1p transporter, and a 'non-saturable' component (diffusion) that is independent of Jen1p. During colony development, the efficiency of both transport components changes similarly in central and outer colonial cells. Although the lactate uptake capacity of central cells gradually decreases during colony development, the lactate uptake capacity of outer cells peaks during the alkali phase and is also kept relatively high in the second acidic phase. This lactate uptake profile correlates with the localization of the Jen1p transporter to the plasma membrane of colony cells. Both lactic acid uptake mechanisms are diminished in sok2 colonies where JEN1 expression is decreased. The Sok2p transcription factor may therefore be involved in the regulation of non-saturable lactic acid uptake in yeast colonies.info:eu-repo/semantics/publishedVersio

Transcriptome remodeling of differentiated cells during chronological ageing of yeast colonies: New insights into metabolic differentiation

We present the spatiotemporal metabolic differentiation of yeast cell subpopulations from upper, lower, and margin regions of colonies of different ages, based on comprehensive transcriptomic analysis. Furthermore, the analysis was extended to include smaller cell subpopulations identified previously by microscopy within fully differentiated U and L cells of aged colonies. New data from RNA-seq provides both spatial and temporal information on cell metabolic reprogramming during colony ageing and shows that cells at marginal positions are similar to upper cells, but both these cell types are metabolically distinct from cells localized to lower colony regions. As colonies age, dramatic metabolic reprogramming occurs in cells of upper regions, while changes in margin and lower cells are less prominent. Interestingly, whereas clear expression differences were identified between two L cell subpopulations, U cells (which adopt metabolic profiles, similar to those of tumor cells) form a more homogeneous cell population. The data identified crucial metabolic reprogramming events that arise de novo during colony ageing and are linked to U and L cell colony differentiation and support a role for mitochondria in this differentiation process

Yeast strains.

<p>Yeast strains.</p

Development and architecture of colonies with altered levels of Cyc8p and Tup1p.

<p>A, Development of colonies grown on GMA at a density of ~10³ colonies per plate (left panel). Two photon excitation confocal microscopy (2PE-CM) of colony cross-sections stained with Calcofluor white (false green color); colonies were grown for 5 days on GMA at a density of ~3 x 10³ colonies per plate (right panel). B, 2PE-CM of colony cross-sections stained with Calcofluor white (false green color). Colonies were grown for 3 days on GMA at a density of ~3 x 10³ colonies per plate. Upper part, whole colonies (20x objective); lower part, central colony parts shown at a higher magnification (63x objective), insets: details of aerial and subsurface cells (strains BR-F and p_GAL-<i>CYC8</i>); detail of central part (p_TEF-<i>CYC8</i>); detail of the colony bottom (<i>tup1</i>). White bar, 100 μm; yellow bar, 20 μm. Arrow indicates chains of rounded cells invading the agar.</p

Model schematic of the regulatory functions of Cyc8p and Tup1p.

<p>In colony biofilms, levels of Cyc8p and Tup1p are balanced in such a way that Tup1p inhibits Cyc8p repressor (by forming Cyc8p-Tup1p complex), thus preventing <i>FLO11</i> repression. In addition, free Tup1p contributes to repression of putative extracellular protease that degrades Flo11p. The Cyc8p-Tup1p complex represses other cellular functions, such as cell flocculation.</p