Aspergillus fumigatus

Scanning electron micrographs of A. fumigatus conidia of transformants rodB-02 (b). Size bar, 100 nm.
<p>Scanning electron micrograph of an A.fumigatus conidium showing the hydrophobic rodlets covering the surface. The surface of many fungal conidia is covered by a thin layer of regularly arranged rodlets. This structure appears to favor air buoyancy and dispersion of the conidia by air currents.See Ref: Paris et al APPLIED AND ENVIRONMENTAL MICROBIOLOGY, Mar. 2003, 1581–1588.</p> <p>&nbsp;</p> <p style="font-family: Verdana, Arial, Helvetica, sans-serif; font-size: 12px; line-height: 1.5; color: rgb(0, 0, 0);">Colonies on&nbsp;CYA&nbsp;40-60 mm&nbsp;diam, plane or lightly wrinkled, low, dense and&nbsp;velutinous&nbsp;or with a sparse,&nbsp;floccose&nbsp;overgrowth; mycelium inconspicuous, white;&nbsp;conidial&nbsp;heads borne in a continuous, densely packed layer,&nbsp;Greyish&nbsp;Turquoise to Dark Turquoise (24-25E-F5); clear&nbsp;exudate&nbsp;sometimes produced in small amounts; reverse pale or greenish. Colonies on MEA 40-60 mm&nbsp;diam, similar to those on&nbsp;CYA&nbsp;but less dense and with&nbsp;conidia&nbsp;in duller&nbsp;colours&nbsp;(24-25E-F3); reverse&nbsp;uncoloured&nbsp;or&nbsp;greyish. Colonies on&nbsp;G25N&nbsp;less than 10 mm&nbsp;diam, sometimes only germination, of white mycelium. No growth at 5°C. At 37°C, colonies covering the available area, i.e. a whole Petri dish in 2 days from a single point&nbsp;inoculum, of similar appearance to those on&nbsp;CYA&nbsp;at 25°C, but with&nbsp;conidial&nbsp;columns longer and&nbsp;conidia&nbsp;darker, greenish grey to pure grey.</p> <p style="font-family: Verdana, Arial, Helvetica, sans-serif; font-size: 12px; line-height: 1.5; color: rgb(0, 0, 0);">Conidiophores&nbsp;borne from surface&nbsp;hyphae,&nbsp;stipes&nbsp;200-400 µm long, sometimes sinuous, with&nbsp;colourless, thin, smooth walls, enlarging gradually into&nbsp;pyriform&nbsp;vesicles; vesicles 20-30 µm&nbsp;diam, fertile over half or more of the enlarged area, bearing&nbsp;phialides&nbsp;only, the lateral ones characteristically bent so that the tips are approximately parallel to the&nbsp;stipe&nbsp;axis;&nbsp;phialides&nbsp;crowded, 6-8 µm long;&nbsp;conidia&nbsp;spherical to&nbsp;subspheroidal, 2.5-3.0 µm&nbsp;diam, with finely roughened or&nbsp;spinose&nbsp;walls, forming radiate heads at first, then well defined columns of&nbsp;conidia.</p> <h4 style="line-height: normal; font-family: Verdana, Arial, Helvetica, sans-serif; color: rgb(0, 0, 0);"><strong>Distinctive features</strong></h4> <p style="font-family: Verdana, Arial, Helvetica, sans-serif; font-size: 12px; line-height: 1.5; color: rgb(0, 0, 0);">This distinctive species can be&nbsp;recognised&nbsp;in the unopened Petri dish by its broad,&nbsp;velutinous, bluish colonies bearing characteristic, well defined columns of&nbsp;conidia. Growth at 37°C is exceptionally rapid.&nbsp;Conidial&nbsp;heads are also diagnostic:&nbsp;pyriform&nbsp;vesicles bear crowded&nbsp;phialides&nbsp;which bend to be roughly parallel to the&nbsp;stipe&nbsp;axis. Care should be exercised in handling cultures of this species.</p>