A comprehensive reference organism is often lacking when studying the adaptation of filamentous fungi to environmental stressors. This work investigates the mechanism underlying the response of N. crassa to stress conditions by focusing on the deletion mutant for the CCG-8 transcription factor. Our molecular analyses revealed that Δccg-8 severely compromises cell surface structure and metabolic homeostasis. Proteomic profiling demonstrated key dysregulations in ribosome biogenesis (consistent with the clock-controlled nature of CCG-8) and fatty acid β-oxidation. These findings, substantiated by changes in ergosterol and fatty acid composition, confirmed the increased susceptibility of deletion mutant to azoles and echinocandins. Furthermore, glycomic and proteomic data suggested that conidia of N. crassa Δccg-8 exhibit protein and glycan alterations. To validate this structural compromise in vivo, we successfully applied the Galleria mellonella larval model. Despite being non-pathogenic, conidia of N. crassa Δccg-8 were cleared significantly faster by the larval immune system than the wild-type strain, mirroring the in vitro observations. This work provides detailed molecular insights into fungal stress adaptation and establishes N. crassa as a viable non-pathogenic organism for in vivo analysis. This approach substantially broadens application of this filamentous fungus, enabling direct comparative research with pathogenic filamentous fungi in the domain of antifungal resistance and host interaction.

With the development of highly sensitive experimental techniques, the mechanical properties of bacterial cells have become an important research topic. However, existing models used to fit experimental data from micro-compression tests often lack accuracy. The aim of this study was to address this limitation by developing a new curve-fitting mathematical model for evaluating the mechanical properties of rod-shaped bacterial cells. The proposed model is based on a thin-shell approach and is specifically designed for the interpretation of single-cell micro-compression experiments. To verify the applicability of the model, single-cell micro-compression tests were performed using a flat-punch nanoindenter tip larger than the bacterial cells. Atomic force microscopy (AFM) was used to obtain detailed morphological information, including precise cell dimensions required for curve fitting. As a model organism, the polyhydroxyalkanoate-producing bacterium Cupriavidus necator H16 was selected due to its ability to accumulate intracellular polyhydroxybutyrate (PHB) granules. For comparison, a mutant strain, C. necator PHB-4, which lacks PHB production, was also analyzed. The results showed that C. necator H16 cells, with an average PHB content of 72% of dry cell weight, exhibited a Young's modulus approximately 16× higher than that of the PHB-4 mutant, indicating a substantial contribution of intracellular PHB granules to cell stiffness. AFM analysis further revealed that PHB-producing cells were, on average, larger in volume than the non-producing mutant. The combination of AFM and micro-compression testing enabled comprehensive characterization of bacterial cell mechanics and demonstrated a clear correlation between PHB content and mechanical behaviour.

[This retracts the article DOI: 10.1016/j.tcsw.2025.100149.].