Doctoral Researchers

 
Ferling (née Viediernikova), Iuliia

cv + contact data »

publications »

ILRS Student

Email »

Institute/Dep.
Leibniz Institute for Natural Product Research and Infection Biology - Hans-Knöll-Institute-
Dept. Molecular and Applied Microbiology
PhD Project:

The role of virulence determinants of the human pathogenic fungus Aspergillus fumigatus in the defense against fungivorous amoeba.

PDF »

Abstract: Infections with opportunistic pathogens are among the leading causes of morbidity and mortality in humans. The filamentous fungus Aspergillus fumigatus represents a classical example...
more
... foe this group, as it normally thrives as saprophyte in the soil, but disperses asexual conidia as infectious agents. Upon inhalation by immunocompromised host, these conidia can germinate and invade the surrounding tissue. Lethality of such an invasive aspergillosis is high due to limited diagnostic and therapeutic options. A multitude of general virulence factors can lead to invasive growth and rapid disease progression with often enormously high death rates, exceeding even 90% in certain patient cohorts (Brakhage and Langfelderk, 2002). Little is known on the evolutionary origin of this armory. In a recent sturdy we could show that two major virulence determinants, formation of the protective DHN-melanin and the second metabolite gliotoxin are also effective against the soil amoeba Dictyostelium discoideum (Hillmann et al., 2015). An amoeba defensive function was also detectable for trypacidin, a spore born toxin of A. Fumigatus with antiphagocytic properties (Mattern et al., 2015). These results supported the idea some basic mechanisms of fungal virulence could have emerged long before the appearance of innate immune systems and foster the hypothesis that they could be driven from the selection pressure imposed by amoeba predation. A central question of my thesis is therefore if interactions with fungivorous amoeba could have stimulated the development of such virulence mechanisms. To address this point I will exploit an extended model system based on the amoeba Protostelium mycophaga, an obligate fungivore which was isolated from a forest site near Jena. Preliminary results in the group of Falk Hillmann indicate that P. mycophaga has wide food spectrum of ascomycetous or basidiomycetous yeasts, but can also attack fungal hyphae. My work program will analyze the molecular interactions with fungal conidia during phagocytosis, but will include first approaches to analyze the chemical communication between these two antagonistic organisms.
 
 
Ferreira Gomes, Marta

cv + contact data »

publications »

JSMC Fellow

Email »

Institute/Dep.
Friedrich Schiller University Jena
Center for Molecular Biomedicine
Laboratory of Cell Biology
PhD Project:

B cells and antibodies in protective immunity to Candida albicans infection

PDF »

Abstract: Candida albicans colonizes mucosal surfaces of most healthy individuals as a benign member of the human microbiota, but may become an invasive pathogen in the immunocompromized host. In...
more
... the clinical setting, C. albicans is a major cause of nosocomial infections and may cause severe bloodstream invasion with mortality rates exceeding those of bacterial sepsis. Basic immunological principles that allow tolerance to this commensal on the one hand but mediate antifungal immunity on the other hand are thus investigated, with the final goal to elicit protective immune responses against this opportunistic pathogen in the human host. While in the context of acute bloodstream infection innate immune responses appear to predominate protection, adaptive immunity is required for long term immunological memory and immunization. In the gut, the major reservoir of C. albicans, the fungus may persist even though it evokes a response from both T and B lymphocytes. The present project will focus on the role of antibodies produced by B cells in the maintenance of benign C. albicans colonization, as well as in protection of individuals from secondary challenges with C. albicans bloodstream infections, to approach the question whether and how a protective antibody response to C. albicans can be triggered in humans.
 
 
Ferreira Lobo da Graça, Ana Patrícia

publications »

Email »

Institute/Dep.
Leibniz Institute for Natural Product Research and Infection Biology - Hans Knöll Institute
Synthetic Microbiology
PhD Project:

Biosynthesis and function of the cryptic cofactor mycofactocin

 
 
Flak, Michal

publications »

Email »

Institute/Dep.
Leibniz Institute for Natural Product Research and Infection Biology - Hans-Knöll-Institute-
Dept. Molecular and Applied Microbiology
 
 
Förster, Toni

cv + contact data »

publications »

FungiNet Student

Email »

Institute/Dep.
Leibniz Institute for Natural Product Research and Infection Biology - Hans-Knöll-Institute-
Dept. Microbial Pathogenicity Mechanisms
PhD Project:

Identification and characterisation of translocation-associated factors of Candida albicans

PDF »

Abstract: Candida albicans is normally a harmless commensal inhabitant of mucosal surfaces, such as the human gut, but is also an opportunistic pathogen. Under certain predisposing conditions, C....
more
... albicans can cause life-threatening systemic infections. This fungus is the most common cause of life-threatening nosocomial fungal bloodstream infections. By crossing the intestinal barrier, C. albicans can access the bloodstream and can cause lethal sepsis. Therefore, understanding the process of this translocation will be crucial for future therapies. The project is divided into two main parts. The first focus of this project is Ece1. Ece1 is a protein which is proteolytically processed into several short peptides, one of which acts as a pore-forming toxin. Such an activity may be crucial for translocation through host barriers. Detailed analysis of C. albicans mutants, lacking ECE1, during interactions with intestinal cells will be performed to elucidate the importance of this protein in translocation. The second part will focus on the identification of novel fungal factors and attributes required for translocation through intestinal epithelial tissue. A translocation assay for screening C. albicans mutant libraries will be established to identify new genes associated with transmigration through intestinal cells. Modified assays with gut-mimicking conditions (e.g. pH, O2) and a more detailed analysis of these new transmigration-associated genes will be carried out. Additionally, the influence of probiotic bacteria on the pathogenicity and translocation of C. albicans will be investigated. The aim here is the development of a commensal-to-pathogen switch model. The presence of bacteria inhibits the epithelial damaging activity of C. albicans. Therefore, by adding antibiotics to a co infection model of bacteria (e.g. Lactobacillae) and C. albicans, the fungus is predicted to switch to a pathogenic form. This process will be followed by transcriptional profiling of the different states during the switch from commensal to pathogen. By elucidating these different aspects of C. albicans colonisation and transmigration, a better understanding of translocation will be achieved, which may ultimately lead to novel treatment strategies to prevent candidaemia.
 
 
Funai, Benjamin

cv + contact data »

publications »

JSMC Fellow

Email »

Institute/Dep.
Friedrich Schiller University Jena
Institute of Microbiology
Microbial Communication
PhD Project:

Combinatorial effects in the heavy metal resistance of streptomycetes

PDF »

Abstract: Actinomycetes and especially the genus Streptomyces, have a unique ability to produce a wide range of biologically-active secondary metabolites and play an important role in the...
more
... pharmaceutical and chemical industry. Due to the fact, that there has been a decline in the discovery of new metabolites from common soil-dwelling actinomycetes, the screening for new metabolites could be enlarged by extreme habitats like heavy metal contaminated sites which could offer the chance to isolate less common actinomycetes. In these habitats, microbes have to cope with rough conditions such as low pH, high concentrations of heavy metals and salts as well as low nutrient contents and therefore evolved several adaptations like heavy metal resistances and potentially new secondary metabolite pathways. Studies have shown that heavy metal stress and co-cultivation can induce a shift in the secondary metabolites pattern by activating gene clusters which are silent under standard screening conditions. By knowing this, a strain collection of actinomycete isolates originating from a former mining area will be screened for their potential to produce antibiotics and other biologically-active secondary metabolites under heavy metal stress and co-cultivation. The experiments will be carried out with different bacteria and yeast isolates as well as several heavy metals in a microfluidic system which is developed by partners of the project „BactoCat - Neue Syntheseleistungen durch Kopplung mikroorganismischer und Metallnanopartikel-katalysierter Prozesse in der Mikroreaktionstechnik 031A161B”.
 
 
Fürst, David

publications »

Email »

Institute/Dep.
Friedrich Schiller University Jena
Institute of Microbiology
Microbial Communication
PhD Project:

Influence of microorganisms on the phytoremediation-potential of different plants on heavy-metal contaminated soils