Kazuo Ueda

Sterol analysis of DMI-resistant and -sensitive strains of Venturia inaequalis

The sterol composition of Venturia inaequalis strains sensitive and resistant to sterol demethylation-inhibiting fungicides (DMI) were analysed. Without DMI treatment, both strains contained ergosta-5,7-dien-3β-ol, ergosterol, ergosta-7,24(241)-dien-3β-ol and ergost-7-en-3β-ol. Ergosta-5,7-dien-3β-ol was the main sterol in both strains. Treatment with fenarimol decreased the 4-desmethyl sterols and accumulated eburicol in both strains, indicating that this fungicide inhibits C14-demethylase of not only the sensitive strain but also the resistant strain. The accumulation of eburicol in the resistant strain occurred at higher concentration of fenarimol than in the sensitive strain.

Ring-A cleavage of 3-oxo-olean-12-en-28-oic acid by the fungus Chaetomium longirostre

Abstract 3-Oxo-olean-12-en-28-oic acid was transformed by the filamentous fungus Chaetomium longirostre into 3,4- seco -olean-12-en-4-ol-3,28-dioic acid and the 21β-hydroxylated compound. A cell-free preparation derived from the fungus converted 3-oxo-olean-12-en-28-oic acid into 3,4- seco -olean-12-en-4-ol-3,28-dioic acid. the ring-A cleavage activity was detected in the soluble fraction of the cell-free preparation and showed a requirement for NADPH.