Cellular and extracellular siderophores of Aspergillus nidulans and Penicillium chrysogenum.

Abstract

Aspergillus nidulans and Penicillium chrysogenum produce specific cellular siderophores in addition to the well-known siderophores of the culture medium. Since this was found previously in Neurospora crassa, it is probably generally true for filamentous ascomycetes. The cellular siderophore of A. nidulans is ferricrocin; that of P. chrysogenum is ferrichrome. A. nidulans also contains triacetylfusigen, a siderophore without apparent biological activity. Conidia of both species lose siderophores at high salt concentrations and become siderophore dependent. This has also been found in N. crassa, where lowering of the water activity has been shown to be the causal factor. We used an assay procedure based on this dependency to reexamine the extracellular siderophores of these species. During rapid mycelial growth, both A. nidulans and P. chrysogenum produced two highly active, unidentified siderophores which were later replaced by a less active or inactive product--coprogen in the case of P. chrysogenum and triacetylfusigen in the case of A. nidulans. N. crassa secreted coprogen only. Fungal siderophore metabolism is varied and complex.

Siderophore Production by Microorganisms Isolated From a Podzol Soil Profile

“…Besides producing coprogen, P. glabrum secreted tetraglycyl ferrichrome (2 nM), ferrrichrysin (0.01 nM), and Fe-dimerum acid (1 nM), whereas P. melinii produced only ferrichrome (0.6 nM). This is in agreement with earlier studies that have detected ferrichromes and coprogens production by a variety of soil Penicillium isolates (Zähner et al, 1963;Ong and Neilands 1979;Charlang et al, 1981). In addition, Konetschny-Rapp et al (1988) detected the production of 33 mg/l (corresponding to 43 µM) ferricrocin in the culture filtrate of P. resticulosum.…”

“…An earlier study showed that N. crassa had the ability to produce only coprogen in comparison to Aspergillus and Penicillium, which secreted several other siderophores (Charlang et al, 1981). It was also found that N. crassa produced two main hydroxamates, coprogen and ferricrocin with concentrations of (Diekmann, 1967;Diekmann and Zähner, 1967;Sayer and Emery, 1968).…”

“…It was observed previously that Asprigillus sp. could produce 0.1 µg/ml (0.13 µM) of ferrichrome, ferricrocin, ferrrichrysin and coprogen (Charlang et al, 1981). However, Konetschny-Rapp et al (1988) measured 14 mg/l (18 µM) ferricrocin and 27 mg/l (34 µM) tri-acetylfusarinin C in the culture filtrate of Asprigillus.…”

The Intracellular Siderophore Ferricrocin Is Involved in Iron Storage, Oxidative-Stress Resistance, Germination, and Sexual Development in Aspergillus nidulans

“…In A. nidulans, N. crassa, and Penicillium chrysogenum, the conidial siderophore storage was found to be an important germination factor, as germination of conidia, which have lost cellular siderophores by treatment with high salt concentrations, fails or is greatly delayed unless a suitable siderophore is supplied (8,16). In agreement, germination of ⌬sidC conidia was delayed under iron-depleted conditions-most likely due to the reduced iron store.…”

Intracellular Siderophores Are Essential for Ascomycete Sexual Development in Heterothallic Cochliobolus heterostrophus and Homothallic Gibberella zeae

“…Intracellular siderophores, in contrast to extracellular ones, have been proposed to play a role in iron storage in mycelia and spores (36) and have been recognized as asexual spore germination factors of Neurospora crassa, Penicillium chrysogenum, and Aspergillus nidulans (9,15). In these species, treatment of asexual spores with solutions with low water activity (high salinity) led to loss of intracellular siderophores stored in the spores and to inhibition or delay of spore germination.…”