Xerophilic · Extended-panel species

Aspergillus nidulans

Sterigmatocystin producer of section Nidulantes. The teleomorph (sexual stage) is Emericella nidulans; the canonical model organism for filamentous fungal biology.

Extended panelXerophilic · Aw ≥ 0.78

Moisture niche · where this species can grow

XerophilicAw < 0.80
MesophilicAw 0.80–0.89
HydrophilicAw ≥ 0.90
Min Aw 0.78
← Drier conditions toleratedRequires liquid water →
Minimum Aw
0.78
EPA reference (GM)
< 0.4 SE/mgMeklin AHHS threshold
Mycotoxin profile
4+ documented
Ecological role
Primary colonizer

The < 0.4 SE/mg reference value is Meklin 2004's AHHS exclusion threshold: the paper retained species whose geometric mean was at least 2 spores per 5 mg dust (≈ 0.4 spores/mg) and eliminated the rest. This species was measured across the 1,096-home AHHS sample and characterized below that threshold, used here as a conservative ceiling on its true GM, not a percentile band. A detected value of X SE/mg implies an elevation factor of at least X ÷ 0.4 over the EPA reference, a lower bound, since the true GM is below 0.4. See the 82-species story for the math.

About Aspergillus nidulans

Aspergillus nidulans (sexual-stage name Emericella nidulans) is a sterigmatocystin-producing Aspergillus and the canonical model organism for filamentous fungal genetics. Its inclusion on extended panels is principally to capture the sterigmatocystin-producing fungi route that A. versicolor (on the standard 36) leaves only partially covered.

Taxonomy

Ascomycota → Eurotiomycetes → Eurotiales → Aspergillaceae → Aspergillus section Nidulantes. Teleomorph name Emericella nidulans.

Ecology and habitat

A. nidulans is a thermotolerant Aspergillus found in soil, decomposing plant matter, and indoor dust. It is unusual among the indoor Aspergilli in having a well-characterized sexual cycle (the Emericella nidulans teleomorph), which has made it the dominant model organism for filamentous fungal cell biology research.

Indoor relevance

Indoor relevance is moderate. A. nidulans is recovered from damp building materials and dust, especially in warmer indoor environments. Its sterigmatocystin production overlaps with A. versicolor on the standard 36, both producing the same penultimate aflatoxin biosynthetic intermediate.

Cardinal physiology

Minimum water activity for growth: Aw 0.78[2]. Growth across 6–48 °C with optimum 35–37 °C, among the more thermotolerant Aspergilli, similar to A. terreus. Sterigmatocystin production has a higher Aw threshold (~0.85) and broader temperature range than growth itself.

Secondary metabolites

Principal mycotoxin: sterigmatocystin. The species also produces emericellins, nidulin, and asperthecin. A. nidulans's sterigmatocystin route is the same metabolic pathway used by A. versicolor. Both species produce the penultimate aflatoxin biosynthetic intermediate.

Compounds documented as produced by Aspergillus nidulans (presence and quantity vary by chemotype, strain, and substrate):

Sterigmatocystin (primary)EmericellinsNidulinAsperthecin

DNA-based detection of a mycotoxin-producing species in household dust does not directly establish exposure to that mycotoxin at any specific concentration.

Lab availability

Some commercial dust testing labs offer this species as an extended-panel option. Specific lab coverage changes over time: check with your laboratory for current panel options.

Related

SterigmatocystinPrimary mycotoxin produced by this species.Aspergillus versicolorPrincipal indoor sterigmatocystin producer on the standard 36.Aspergillus ustusRelated species producing austocystins.Beyond the 36

References

  1. Meklin T, Haugland RA, Reponen T, Varma M, Lummus Z, Bernstein D, Wymer LJ, Vesper SJ. Quantitative PCR analysis of house dust can reveal abnormal mold conditions. J Environ Monit. 2004;6(7):615–620.
  2. Pitt JI, Hocking AD. Fungi and Food Spoilage. 3rd ed. New York: Springer; 2009.
  3. Engelhart S, Loock A, Skutlarek D, Sagunski H, Lommel A, Färber H, Exner M. Occurrence of toxigenic Aspergillus versicolor isolates and sterigmatocystin in carpet dust from damp indoor environments. Appl Environ Microbiol. 2002;68(8):3886–3890.
  4. International Agency for Research on Cancer. IARC Monographs on the Evaluation of Carcinogenic Risks to Humans, Vol. 10. Lyon: IARC; 1976.