||Caption: Aspergillus nidulans hyphae and sexual spores.Aspergillus nidulans (also known as Emericella nidulans) is a filamentous fungus that is the only member of the genus Aspergillus that forms sexual spores through meiosis (seen here in this image as large spores). A. nidulans is also a homothallic fungus, meaning it can form asexual spores by producing conidiphores that bear chains of asexual spores (conidia produced without a mating partner). Aspergillus species are common saprophytic molds that grow in household dust, soil, and decaying vegetable matter, including stale food. A. nidulans has been an important research organism for studying eukaryotic cell biology and has a long history of use for the study of a wide range of subjects including basic genetic problems (recombination, DNA repair, mutation), cell cycle control and pathogenesis, as well as metabolism of other Aspergillus species. A.nidulans produces the toxin, sterigmatocysin, which may lead to food contamination. Repeated inhalation of A.nidulans spores also causes allergic aspergillosis, a hypersensitive lung reaction in people who have asthma. Mycetoma (Madura foot) may result when this fungus infects subcutaneous tissue, bone and skin.