Hyphae at the outer part of colonies of Aspergillus niger and Aspergillus oryzae are heterogeneous with respect to transcriptional and translational activity. This heterogeneity is maintained by... Show moreHyphae at the outer part of colonies of Aspergillus niger and Aspergillus oryzae are heterogeneous with respect to transcriptional and translational activity. This heterogeneity is maintained by Woronin body mediated closure of septal pores that block interhyphal mixing of cytoplasm. Indeed, heterogeneity between hyphae is abolished in ΔhexA strains that lack Woronin bodies. The subpopulation of hyphae with high transcriptional and translational activity secretes enzymes that degrade the substrate resulting in breakdown products that serve as nutrients. The role of hyphae with low transcriptional and translational activity was not yet known. Here, we show that this subpopulation is more resistant to environmental stress in A. oryzae, in particular to temperature stress, when compared to hyphae with high transcriptional and translational activity. Notably, all hyphae of the ΔhexA strain of A. oryzae were sensitive to heat stress explained by the reduced heterogeneity in this strain. Together, we show that different subpopulations of hypha secrete proteins and resist heat stress showing the complexity of a fungal mycelium. Show less
This study investigated carbon starvation in the filamentous fungus Aspergillus niger during submerged cultivation in bioreactor batch cultures. The work described in this thesis can be discussed... Show moreThis study investigated carbon starvation in the filamentous fungus Aspergillus niger during submerged cultivation in bioreactor batch cultures. The work described in this thesis can be discussed as follows: (I) Establishment of computational resources for omics data analysis and interpretation in chapters 2 and 3; (II) Cultivation of A. niger, data generation, analysis and interpretation in chapter 4; (III) Investigation of a candidate pathway with strong transcriptional induction during carbon starvation by molecular genetic approaches in chapter 5. Show less
