how to detect a colorless fungus on TLC-plate

Friedemann Greulich friede at
Wed Mar 4 09:54:42 EST 1998

Dear Mycologists,

I got good results with the detection of fungitoxic compounds on
TLC-plates by spraying spores suspensions of Cladosporium herbarum and
other dark growing fungi in sugar/mineral medium on the plates.
This bioautography is a good old method - you get white spots in the
dark mycelium and can put it just on a copy machine for documentation.

Now I am working with special pathogenic fungi which grow colorless. I
can detect active spots only because of different roughness of the
TLC-plate surface if I place the light in a good angle.

Charcoal powder is sticking better to the mycelium than to the bald
spots, but this depends much on the moisture. To wet and it sticks all
over, to dry no where.

Heating turns the mycelium dark but also the sugar - no contrast.

Rose bengal solution colors the fungus, but also the plate and the
compounds in the active spots - no contrast.

Any good ideas?

Dr. Friedemann Greulich, Hokkaido Univ., Fac. of Agriculture
Japan, 060-0809 Sapporo, Kita-ku, Kita 9 Nishi 9
Tel.: (+81-11) 706-3349, Fax: ...-2505, priv. Tel./Fax: 614 3099
e-mail: friede at

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