Doctoral Researchers

 
Vielreicher, Sarah

cv + contact data »

publications »

ILRS Student

Email »

Institute/Dep.
Leibniz Institute for Natural Product Research and Infection Biology - Hans-Knöll-Institute-
Research Group
Microbial Immunology
PhD Project:

Gut microbiota mediated colonization resistance against Candida albicans

PDF »

Abstract: The opportunistic fungus Candida albicans is a common member of the human microbiome and present on different mucosal surfaces of healthy individuals. Changes in gut environment, for...
more
... example due to antibiotic treatment, can lead to enhanced fungal proliferation, and in combination with immunosuppression result in superficial or systemic infections. Disseminated infections by C. albicans have become a major health risk factor over the last decades especially in intensive care units. The fact that antibiotics are a major risk factor and recent research highlights the critical role of the bacterial microbiota in controlling C. albicans colonization and translocation. The underlying mechanisms, as well as the types and features of bacteria involved in colonization resistance, are however only incompletely understood. Aim of the project is to address the influence of the microbiota during the colonization and translocation of C. albicans on the host and the clinical outcome of systemic candidiasis. To investigate which members influence C. albicans colonization, mouse colonies with different microbiome compositions will be selected and resistance to C. albicans colonization will be analyzed. Further, the influence of the microbiome on the susceptibility to the development of systemic candidiasis will be examined. Additionally, the spatial organization of the microbiota in mice, and specifically of bacteria in direct physical contact with C. albicans, will be illustrated with the help of different imaging techniques, for example FISH. Thereby, this project will provide new insights into the interaction network of C. albicans and the other members of the gut microbiome.
 
 
Vivas, Wolfgang

cv + contact data »

publications »

JSMC Fellow

Email »

Institute/Dep.
Leibniz Institute for Natural Product Research and Infection Biology - Hans-Knöll-Institute-
ZIK Septomics
Research Group Fungal Septomics
PhD Project:

Modulation of Dendritic Cell Function by the fungal Quorum Sensing Molecule Farnesol

PDF »

Abstract: Quorum Sensing is a major mechanism of inter-microbial communication mediated by molecules that are released from growing microorganisms and accumulate in relation to microbial...
more
... replication. Farnesol – the first identified fungal quorum sensing molecule – mediates the response of Candida albicans to growing population density and controls filamentation of C. albicans which is a major virulence trait. Beside species-specific effects on C. albicans, farnesol can exert effects on other microbes and is therefore a prototype mediator of inter- and intraspecies microbial communication. In previous work we have investigated the impact of farnesol on innate immune cells. For this, we used several infection models with primary human monocytes, monocytes-derived dendritic cells, and neutrophilic granulocytes that are established in our lab. Farnesol was able to induce activation of neutrophils and monocytes and triggered the release of pro-inflammatory cytokines. In contrast, farnesol impaired differentiation of monocytes into dendritic cells (DC) by modulating the phenotype, cytokine release and migrational behavior during differentiation. These modulatory effects resulted in severely impaired induction of antifungal activity in DC. In the proposed project, we will build from this work and try to elucidate the molecular basis of farnesol mediated DC differentiation, maturation and functionality. We will use of state of the art microbiological and immunological tools, primarily working with monocytes-derived DC. The project is built on several collaborations, including Prof. Dr. Marc Thilo Figge.