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Cryptococcus neoformans virulence factors
Bauer, Martin ; Kuthan, Martin (advisor) ; Abrhámová, Kateřina (referee)
Cryptococcus neoformans is an opportunistic pathogenic yeast causing around 600 000 deaths annually. Its ability to cause a chronic infection is given by multiple virulence factors, which include the ability to grow in high temperature, polysaccharide capsule, oxidative stress tolerance and the expression of surface proteins. Unusual and resistant titan cells, which develop through the process of titanization, and the process of phenotypic switching can also be included. Despite intensive research, these virulence factors are yet to be fully described. Inducing factors of titan cells and participating signalling pathways are known. However, a complete model of titanization does not yet exist. So far, the mechanism of phenotypic switching is also unknown. In this work the current knowledge of virulence factors of C. neoformans is presented and summarised.
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Phenotypic switching and cell differentiation in yeast Cryptococcus neoformans
Bauer, Martin ; Kuthan, Martin (advisor) ; Abrhámová, Kateřina (referee)
Cryptococcus neoformans is an opportunistic pathogenic yeast causing around 600 000 deaths annually. Its ability to cause a chronic infection is given by the emergence of different morfotypes. These morphotypes differ in cell structures and mechanisms (virulence factors) which have an influence on the resistance to stress factors encountered in the host. This work first describes molecular mechanisms of formation of these virulence factors. Next, it presents morphotypes occurring during infection and the hypovirulent pseudohyphal morphotype. However, this morphotype is interesting because of a modification in the signalisation leading to its manifestation. Finally, described signalling pathways present possible ways of regulating the virulence factors, and so the manifestation of different morphotypes. Understanding these signalling pathways could ultimately lead to improving the development of new drugs, given that Cryptococcus neoformans is highly resistant to the existing ones. Keywords: Cryptococcus neoformans, phenotypic switching, titan cells, cell differentiation, virulence, Vad1, Rim101, Usv101, RAM
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