Yeast Saccharomyces cerevisiae as an unicellular organism is one of the best-studied experimental organisms. It is an important model organism for the study of intracellular processes of eukaryotic cells. Yeasts are also social organisms with cell-to-cell communication able to form organized multicellular structures (colonies and biofilms). Yeast and other microorganisms in nature prefer to form colonies on solid substrates rather than to grow as "planktonic" single cells (Palková, 2004; Wimpenny, 2009). The yeast S. cerevisiae typically forms colonies, biofilms were described only rarely. Yeast colonies exhibit an organized morphological pattern characteristic of each particular yeast strain (Kocková-Kratochvílová, 1982). This work is focusing on morphology and differentiation of the S. cerevisiae colonies of common laboratory strains forming less structured colonies, and strains of the Σ1278b genetic background forming highly structured "fluffy" colonies. It shows that polarized budding pattern and especially cell ability to form aggregates enable development of structured morphology. During development of "fluffy" colonies two differently regulated events of dimorphic switch from yeast form to filamentous growth occur. One of these events is dependent on the surface glycoprotein, Flo11p flocculin. This...

5 Abstract Although yeasts are unicellular microorganisms, they form complex multicellular formations such as biofilms and colonies under natural conditions. Within these structures, processes such as cell differentiation, specialization by particular cell populations and cell signalling, which are typical of multicellular organisms, take place. The literature introduction to this thesis summarizes current knowledge regarding the development of biofilms and colonies, in particular those of the model organism, Saccharomyces cerevisiae, and some selected regulations that are important for the formation of multicellular structures. In the results section, I focus on two lines of research. The first is directed towards mechanisms, involved in the formation of multicellular structures. In studying the formation of SLI biofilms (biofilms at the solid/liquid interface), we have documented the antagonistic role of the regulators CYC8 and TUP1 in their formation and have also described the effect of the presence of glucose on the development and stability of SLI biofilms of strain BR-F. During this study we[D1] have developed an imaging method that allows us to prepare and observe the internal structure (vertical cross-section) of SLI biofilms, as well as the growth of unattached cells, under physiological...

Egyptian fruit bats were observed in Prague Zoo, where stable conditions are provided (year-round food supply, stable temperature and roosts). The colony has bimodal breeding cycle. Births are synchronized and occur on the turn of April and May and in September. The mating occurs throughout the year but there is an increase during lactation and in the period outside parturitions. There is no obvious pattern in cluster dynamics. Bats roost in four clusters (left, middle, upper right and lower right). The presence of clusters throughout the year is stable except upper right cluster. There are changes in the number of clusters and in the number of individuals inside each cluster. Fruit bats occupy approximately the same spots in clusters, however young individuals show the highest variability. An autogrooming is balanced throughout the year, there is no regular pattern in the observation period and even no increase after artificial twilight. From these activities a licking of wing membranes and fur are the most often. The mother cares for her young especially during lactation and weaning, while the care decreases with a development of the young. This is especially true for the licking of the wing membranes. An allogrooming is the most common between male and female during lactation and in the period...

On solid surfaces wild strains of Saccharomyces cerevisiae form biofilm-like, structured colonies enabling them to survive long-term in hostile environments in the wild. However, the molecular mechanisms underlying the spatio-temporal development of colonies and their resistance to hostile conditions are still largely unknown. In this study, we analyzed the effect of the HAC1 gene on the colony morphology of wild strains of S. cerevisiae. The transcription factor Hac1p activates the unfolded protein response (UPR), which leads to activation of the expression of genes encoding components of the protein secretory pathway, and genes involved in stress responses in the endoplasmic reticulum (ER). The impact of HAC1 deletion is significant even under non-stress conditions and causes a radical reduction of structured colony architecture in hac1∆ strains derived from two wild S. cerevisiae strains (PORT and BR-F-Flo11p-GFP) and one laboratory ΣSh strain forming semi-fluffy or fluffy colonies. The hac1∆ strains exhibit a decreased vegetative growth rate, reduced cell attachment to the agar and an ineffective cell-cell adhesion resulting in decreased flocculation. The hac1∆ strains derived from BR-F-Flo11p-GFP contain a low level of Flo11p surface adhesin which is considered very important for the proper...

Diss. Univ. Konstanz, 2007.

Diss. Univ. Konstanz, 2007.

This thesis examines the influence of packaging on the microbial condition of beef for sale. The beef - Muscullus semimembranosus - was studied in an unpackaged state, and in the packaging of stretchable plastic wrap, in multilayer polyamide - polyethylene (PA / PE) wrap using a protective atmosphere and using 80% of vacuum into a bag from a multi-layered PA / PE wrap. The beef was stored at refrigerated temperature of +5 ° C. The total number of microorganisms (the number of colony forming units) were examined for 27 days. The compared samples show that the speed of increasing number of microorganisms is dependent on the type of packaging. According to the observed averages the best results are showed at meat packaged into a modified atmosphere and vacuum packaging, where there were no significant differences between these two types. Statistically there were no sigificant differences between the observed types of packaging. Packing in plastic wrap reduced microbial contamination of meat compared to unpackaged meat, but with vacuum packaging and modified atmosphere it could not be compared.

The phosphatidylinositol-3-kinase (PI3K) signalling pathway is evolutionarily conserved in all eukaryotes and its main function is the regulation of autophagy and protein sorting to the vacuole/lysosome. In the pathogenic yeast species Candida albicans and Cryptococcus neoformans the PI3K signalling pathway is required for virulence. In the yeast Saccharomyces cerevisiae the PI3K signalling pathway consists of two proteins - phosphatidylinositol-3-kinase, Vps34p and its regulator Vps15p. In this diploma thesis I analyse the role of the PI3K signalling pathway in the growth and development of colonies of natural and laboratory strains. I proved that VPS34 or VPS15 deletion in haploid laboratory strains has a significant influence on colony size and invasive growth (in strain ΣSh vps15Δ). Deletion of VPS34 or VPS15 also increases sensitivity of cells to oxidative stress and detergents. Attempts to delete VPS34 in natural strains were unsuccesful, probably because VPS34 is essential in these strains. Constitutive expression of VPS34 does not affect cell resistance in inhibitory tests, the size and differentiation of colonies or ammonia signalling but differences are notable in giant colony morphology and in patterns of invasiveness of the medium. Tagging of the C-terminal of Vps34p with GFP affects...

This diploma thesis, titled "Presence of Colonial Past in Contemporary Portugal", deals with how the Portuguese society has coped with their loss of the last colonies after the democratic revolution in the year 1974. Portugal belonged, along with Spain, to the first colonial powers in Europe and for long time - till the 20th century - the independence of colonies was for many Portuguese people unimaginable. Therefore a lot of them were surprised with the speedy decolonization of these territories after 1974. Investigation of reactions of Portuguese society to this change is based on the analysys of responses of its political and academic communities after the year 1976. Attitudes held by the wider society was demonstrated by the massive support of Portuguese to the former colony of East Timor during Semptember 1999. The approach of politicans is analysed in this work through their speeches during the key' historical moments, which influenced relations between Portugal and its former colonies during the years 1976-1996, as well as through government' programmes and comments in mass media. Analysis of academical discussion is concentrated mainly on the 1990s and present, when the colonial past has became a topic of great interest to many portuguese perits. A new field of academic interest, reffered...

Master's thesis deals with the Red Hill, a place situated inside the urban area of Brno, close to the historic center, close to the newly established and still growing campus of Masaryk University. Red hill with its gardening colony remains blank space on the map of Brno, the goal here was to create a functional urban structure that would place the space in the city map. Not to make an urban mash on the peripherals, but build a real city organism into the hearth of the city Brno.