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Emericella nidulans (Eidam) Vuill Link to species page

For Emericella nidulans in clinical material click here

Anamorph: Aspergillus nidulans (Eidam) G. Winter

E nidulans conidial hea
E nidulans growing on laboratory medium
E nidulans conidia
E nidulans conidia
E nidulans conidial head, colour image
E nidulans Hulle cells
E nidulans conidia
E nidulans
E nidulans asci
E nidulans hulle cells
E nidulans acospores
   

Colonies on CYA 40-50 mm diam, plane, low, moderately dense to dense, sometimes with a floccose overlay; mycelium white; cleistothecia white, surrounded by white to buff or dull yellow Hülle cells; conidial heads sparse to quite dense, radiate when young, later forming long well defined columns, conidia coloured pale green or when dense Dark Green (25E5-F7); exudate sometimes present, dull red to brown; violet soluble pigment sometimes produced; reverse sometimes pale, usually brightly coloured in shades of orange, orange brown, deep brown or violet brown (10E-F5). Colonies on MEA 35-60 mm diam, occasionally only 25 mm, sometimes low, plane and velutinous with heavy conidial formation and few cleistothecia, sometimes deeper and with abundant cleistothecia surrounded by dull yellow or buff Hülle cells; mycelium white; cleistothecia sometimes abundant, surrounded by Hülle cells, at other times sparsely produced; conidia Dark Green (26-29E-F5-7); reverse pale, brown or violet brown. Colonies on G25N 10-15 mm diam, low and dense; conidia pale green; reverse pale. No growth at 5°C. At 37°C, colonies 50-70 mm diam, low and sparse, usually predominantly cleistothecial, sometimes with areas of dark green conidia; reverse usually orange or brown.

Cleistothecia mostly 100-250 µm diam, white at first but at maturity dark red, maturing on CYA in 8-10 days, surrounded by heavy walled Hülle cells, 15-25 µm diam; ascospores red to purple, ellipsoidal, 4-6 µm long, smooth walled, usually ornamented with two conspicuous longitudinal flanges. Conidiophores borne from aerial hyphae, stipes 60-150 µm long, often sinuous, with smooth, brown walls and with conspicuous footcells; vesicles spathulate to pyriform, 8-12 µm wide, bearing metulae and phialides over the upper half or less, of similar size, 6-8 µm long; conidia spherical, green, 3.0-3.5 µm diam, with roughened walls, borne in radiate to loosely columnar heads.

Distinctive features

Emericella nidulans is distinguished by growth on CYA at least as fast at 37°C as at 25°C, developing cleistothecia surrounded by Hülle cells and sparse to abundant green conidia borne on metulae and phialides from diminutive brown walled stipes. Mature ascospores are red, and have either two longitudinal flanges or no ornamentation. Other Emericella species show different ascospore ornamentation.

Media

Czapek yeast extract agar (CYA)

K2HPO4 1 g
Czapek concentrate 10 ml
Trace metal solution 1 ml
Yeast extract, powdered 5 g
Sucrose 30 g
Agar 15 g
Water, distilled 1 litre

Refined table grade sucrose is satisfactory for use in CYA provided it is free from sulphur dioxide. Sterilise by autoclaving at 121°C for 15 min. Final pH 6.7.

Czapek concentrate

NaNO3 30 g
KCl 5 g
MgSO4.7H2O 5 g
FeSO4.7H2O 0.1 g
Water, distilled 100 ml

Czapek concentrate will keep indefinitely without sterilisation. The precipitate of Fe(OH)3 which forms in time can be resuspended by shaking before use.

Trace metal solution

CuSO4.5H2O 0.5 g
ZnSO4.7H2O 1 g
Water, distilled 100 ml

Keeps indefinitely without sterilisation.

Malt extract agar (MEA)

Malt extract, powdered 20 g
Peptone l g
Glucose 20 g
Agar 20 g
Water, distilled l litre

Commercial malt extract used for home brewing is satisfactory for use in MEA, as is bacteriological peptone. Sterilise by autoclaving at 121°C for 15 min. Do not sterilise for longer, as this medium will become soft on prolonged or repeated heating. Final pH 5.6.

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