We describe a novel heterothallic species in Aspergillus section Fumigati, namely A. felis (neosartorya-morph) isolated from three host species with invasive aspergillosis including a human patient with chronic invasive pulmonary aspergillosis, domestic cats with invasive fungal rhinosinusitis and a dog with disseminated invasive aspergillosis. Disease in all host species was often refractory to aggressive antifungal therapeutic regimens. Four other human isolates previously reported as A. viridinutans were identified as A. felis on comparative sequence analysis of the partial β-tubulin and/or calmodulin genes. A. felis is a heterothallic mold with a fully functioning reproductive cycle, as confirmed by mating-type analysis, induction of teleomorphs within 7 to 10 days in vitro and ascospore germination. Phenotypic analyses show that A. felis can be distinguished from the related species A. viridinutans by its ability to grow at 45°C and from A. fumigatus by its inability to grow at 50°C. Itraconazole and voriconazole cross-resistance was common in vitro.

Airborne and waterborne fungal spores were compared with respect to cytoplasmic viscosity and the presence of ergosterol. These parameters differed markedly between the two spore types and correlated with spore survival. This suggests that the mode of spore dispersal has a bearing on cellular composition, which is relevant for the eradication of industrially relevant fungal propagules.Contamination of food products by fungi often starts with dispersal vehicles that include air-and waterborne spores. The aim of this study was to assess whether air-and waterborne spores are not only different with respect to surface wettability but also have a distinct membrane and cytoplasmic composition. To this end, microviscosity and the presence of ergosterol in the plasma membrane were determined. Ergosterol is the target of many antifungals, and its presence or absence will affect sensitivity to such antifungals, including natamycin. Natamycin is considered a fungistatic antibiotic. It binds to ergosterol but is not able to disrupt the plasma membrane (9, 11). In this study, conidia of Penicillium discolor, Aspergillus niger (airborne), Fusarium oxysporum, and Verticillium fungicola (waterborne) were used. All of these species are relevant in applied situations ranging from postharvest diseases (Aspergillus and Fusarium) and food spoilage (Penicillium) to mycoparasitism of mushrooms (Verticillium). A. niger N402 and P. discolor CBS112557 were grown on malt extract agar (MEA; 7) at 25°C. F. oxysporum CBS116593 and V. fungicola MES12712 were grown on oatmeal agar (7) at 25°C. Low-temperature scanning electron microscopy of uncoated samples (8) clearly showed that the conidia of Verticillium and Fusarium were formed in large (spherical) clusters or on the surface of the colony amid the mycelium, while the other fungi showed clearly elevated spore-forming structures that formed chains of conidia (Fig. 1). Conidia of 10-to 12-day-old cultures were harvested in cold ACES buffer [10 mM N-(2-acetamido)-2-aminoethanesulfonic acid, 0.02% Tween 80, pH 6.8] and stored on ice before experimentation on the same day.Cytoplasmic microviscosity of air-and waterborne spores. The viscosity of the interior of the cell has been correlated with the dormancy and stress resistance of fungal spores (1). Spin label electron spin resonance (ESR) spectroscopy was utilized to measure the cytoplasmic microviscosity of conidia using the spin label perdeuterated TEMPONE (4-oxo-2,2,6,6-tetramethylpiperidine-

Hydrophilins are proteins that occur in all domains of life and protect cells and organisms against drought and other stresses. They include most of the late embryogenesis abundant (LEA) proteins and the heat shock protein (HSP) Hsp12. Here, the role of a predicted LEA-like protein (LeamA) and two Hsp12 proteins (Hsp12A and Hsp12B) of Neosartorya fischeri was studied. This filamentous fungus forms ascospores that belong to the most stress-resistant eukaryotic cells described to date. Heterologous expression of LeamA, Hsp12A and Hsp12B resulted in increased tolerance against salt and osmotic stress in Escherichia coli. These proteins were also shown to protect lactate dehydrogenase against dry heat and freeze-thaw cycles in vitro. Deletion of leamA caused diminished viability of sexual ascospores after drought and heat. This is the first report on functionality of Hsp12 and putative LeamA proteins derived from filamentous fungi, and their possible role in N. fischeri ascospore resistance against desiccation, high temperature and osmotic stress is discussed.