Growth rates, the optimum temperature of growth, and colony characteristics
were determined on three different media at four different temperatures. The
strains were pregrown on CMD, or MEA (2 % malt extract, 2 % agar-agar, both
from Merck) where noted, until they reached a diameter of 55–65 mm. Agar
plugs 0.5 cm diam were then cut from the margin of the colonies and
transferred to fresh medium, 1.0–1.5 mm from the edge of the 9-cm-diam
Petri dish with the mycelium facing down on the surface of the agar. CMD, PDA
(potato dextrose agar, Merck, Darmstadt, Germany) and low nutrient agar (SNA,
Nirenberg 1976; pH adjusted to 5.5) were used. The tests were performed at 15
°C (with alternating 12 h weak UV light (Philips TL-D/08 blacklight blue)
and 12 h darkness), 25 °C (with alternating 12 h cool white fluorescent
light and 12 h darkness), and 30 °C and 35 °C (both in darkness). The
different lighting conditions were due to a simultaneous use of incubators to
culture for anamorph morphology. For growth at 25 °C, the Petri dishes
were sealed with Parafilm to avoid drying out of the agar caused by the
ventilator of the cooling incubator (MIR 153, Sanyo, Gunma, Japan). The
maximum colony radius was measured once daily for at least 7 d or until the
plates were entirely covered with mycelium. The growth rate was calculated by
linear regression of log t versus log r (t = time of incubation, r = radius
measured from the edge of the agar plug), using only measurements from the
phase where the logarithmic increase of the colony radius was linear over log
t. The data given are ranges obtained from 3–6 experiments for all media
and temperatures, except species with stipitate stromata, H. alutacea, H.
nybergiana and H. seppoi, where only single experiments were
carried out.
In addition, the plates were examined daily under the compound microscope
at low magnification (10× objective), and the time of first appearance
of conidia, autolytic behaviour of marginal hyphae, coilings in surface
hyphae, presence of chlamydospores, formation of pigments and odour, and the
colony appearance were noted.
were determined on three different media at four different temperatures. The
strains were pregrown on CMD, or MEA (2 % malt extract, 2 % agar-agar, both
from Merck) where noted, until they reached a diameter of 55–65 mm. Agar
plugs 0.5 cm diam were then cut from the margin of the colonies and
transferred to fresh medium, 1.0–1.5 mm from the edge of the 9-cm-diam
Petri dish with the mycelium facing down on the surface of the agar. CMD, PDA
(potato dextrose agar, Merck, Darmstadt, Germany) and low nutrient agar (SNA,
Nirenberg 1976; pH adjusted to 5.5) were used. The tests were performed at 15
°C (with alternating 12 h weak UV light (Philips TL-D/08 blacklight blue)
and 12 h darkness), 25 °C (with alternating 12 h cool white fluorescent
light and 12 h darkness), and 30 °C and 35 °C (both in darkness). The
different lighting conditions were due to a simultaneous use of incubators to
culture for anamorph morphology. For growth at 25 °C, the Petri dishes
were sealed with Parafilm to avoid drying out of the agar caused by the
ventilator of the cooling incubator (MIR 153, Sanyo, Gunma, Japan). The
maximum colony radius was measured once daily for at least 7 d or until the
plates were entirely covered with mycelium. The growth rate was calculated by
linear regression of log t versus log r (t = time of incubation, r = radius
measured from the edge of the agar plug), using only measurements from the
phase where the logarithmic increase of the colony radius was linear over log
t. The data given are ranges obtained from 3–6 experiments for all media
and temperatures, except species with stipitate stromata, H. alutacea, H.
nybergiana and H. seppoi, where only single experiments were
carried out.
In addition, the plates were examined daily under the compound microscope
at low magnification (10× objective), and the time of first appearance
of conidia, autolytic behaviour of marginal hyphae, coilings in surface
hyphae, presence of chlamydospores, formation of pigments and odour, and the
colony appearance were noted.
