Project description:The study consists of the pathogens Lichtheimia corymbifera, Lichtheimia ramosa and non-pathogen Lichtheimia hyalospora untreated (control, CTRL) and during HSP90 inhibition (Geldanamycin, GDA), endoplasmic reticulum stress (Dithiothreitol, DTT), thermal stress (42°C, HEAT) and heat stress upon a concentration of 0.5 M NaCl (L. hyalospora only)
Project description:Mucormycosis is a life-threatening disease especially in immunocompromised patients that was caused my mucoralean fungi. The rate of mortality is tremendously increased in the last decades due to the lack of appropriate diagnostic tools, insufficient knowledge about the immune response toward the mucormycosis and unavailability of specific antifungal drugs. Several species of mucoralean fungi cause mucormycosis such as Lichtheimia, Rhizopus, and Mucor. Lichtheimia species ranks the second and third cause of mucormycosis in Europe and the USA, respectively. In this study, we investigated the receptors present on the surface of immune cells that bind to the spores of Lichtheimia. We focus on two strains of L. corymbifera (FSU:9682 and FSU:10164) using resting and heat-killed spores. Additionally, we choose alveolar macrophages (MH-S) to carry out our experiment. MH-S is the first line of defense in the lung and the major component in the innate immune system. MH-S surface proteins were biotinylated and incubated with Lichtheimia spores. The surface proteins and putative binding partners were enriched by streptavidin. LC-MS/MS analysis showed that several proteins are highly expressed in presence of Lichtheimia spores, of which the heat shock protein family A (HSPA8) was one of the most abundant proteins. FACS analysis and immunofluorescence examination confirmed that HSPA8 is highly abundant on the surface of the MH-S, but not on the surface of Lichtheimia spores. Moreover, our study showed that the intensity of HSPA8 on the surface of MH-S depends on the multiplicity of infection (MOI). Additionally, the blocking with anti-HSPA8 antibody reduced the capability of MH-S to engulf the Lichtheimia spores, but not Aspergillus fumigatus spores. This confirms that HSPA8 is specific to Lichtheimia. THis is the first study addressing the determination of surface receptors of alveolar macrophages that in the context of Mucoralean fungi.
Project description:Reconstruction of signaling networks regulating fungal morphogenesis by the expression profiling of wild-type and the temperature sensitive morphological ramosa-1 mutant. Aspergillus niger wildtype versus Ramosa mutant for 1h at 37 under controlled growth condition in 5L bioreactor
Project description:The parasitic lifestyle of parasitic plants relies on the development of a haustorium, a specific infectious organ required for attachment to host roots. While haustorium development is initiated upon chemodetection of host-derived molecules in hemiparasitic plants, the induction of haustorium formation remains largely misunderstood in holoparasitic species such as Phelipanche ramosa. This work demonstrates that the root exudates of the host plant Brassica napus contain allelochemicals displaying a haustorium-inducing activity on P. ramosa germinating seeds which increases the parasite aggressiveness. A de novo assembled P. ramosa transcriptome and a microarray approach during early haustorium formation upon treatment with B. napus root exudates allowed the identification of differentially expressed genes involved in hormone signaling. Bioassays using exogenous cytokinins and the specific cytokinin receptor inhibitor PI55 showed that cytokinins induced haustorium formation and increased parasite aggressiveness. Root exudates triggered the expression of cytokinin responsive genes during early haustorium development in germinated seeds and bio-guided UPLC-MS analysis showed that these exudates contain a cytokinin with dihydrozeatin characteristics. These results suggest that cytokinins constitutively exudated from host roots play a major role in haustorium formation and aggressiveness in P. ramosa.
