Lipid, membrane, and mitochondrial characteristics of Ustilago maydis following exposure to ergosterol biosynthesis inhibitors
Pencoazole at 0.5 ..mu..g/ml inhibited ergosterol biosynthesis in U. maydis. Polar lipids of sporidia grown with 0.5 ..mu..g/ml penconazole for 7.5 or 22 hr or 1.0 ..mu..g/ml fenarimol for 7.5 hr contained more 18:2 than 18:1 fatty acids. There was usually more 18:1 than 18:2 fatty acids in polar lipids of untreated sporidia but this ratio was influenced by culture cell density. The high 18:2 to 18:1 ratio in the polar lipids from penconazole grown cells was unaffected by cell density. There was an increase in free fatty acids and these were enriched with 18:2 members in cells grown with 0.5 ..mu..g/ml penconazole for 22 hr. Unsaturation of triglycerides fatty acids did not differ appreciably from that of untreated sporidia. Untreated WT U. maydis protoplasts lysed more slowly in 0.3 M sorbitol than those prepared from WT sporidia grown for 16 hr with 1.0 ..mu..g/ml penconazole or 2.0 ..mu..g/ml fenarimol or from untreated erg-40 sporidia. Protoplasts were more permeable to crystal violet than were those from untreated WT sporidia. Mitochondria from untreated WT sporidia oxidizing pyruvate plus malate or succinate yielded higher ADP/O rations than mitochondria from erg-40 or penconazole grown WT sporidia. The mitochondrial ATPase of control cells had a Km of 0.8 mM ATP whereas the mitochondrial ATPase of penconazole grown WT and erg-40 had a Km value of 3.7 and 3.2 mM ATP, respectively. When the mitochondrial catalytic subunit of the ATPase from these mitochondria were solubilized, the Km did not differ. These studies suggest that changes in sterols and membrane fatty acids resulting from treatments with EBI fungicides cause increased membrane fluidity which affects membrane stability, permeability and activity of the mitochondrial ATPase.
- Research Organization:
- Maryland Univ., College Park (USA)
- OSTI ID:
- 6859967
- Resource Relation:
- Other Information: Thesis (Ph. D.)
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ATP-ASE
ENZYME ACTIVITY
CELL MEMBRANES
PERMEABILITY
FUNGICIDES
TOXICITY
USTILAGO
BIOSYNTHESIS
CARBOXYLIC ACIDS
DYES
ERGOSTEROL
INHIBITION
LIPIDS
MALIC ACID
MITOCHONDRIA
PLANT CELLS
PYRUVIC ACID
SPORES
SUCCINIC ACID
ACID ANHYDRASES
CELL CONSTITUENTS
DICARBOXYLIC ACIDS
ENZYMES
FUNGI
HYDROLASES
HYDROXY ACIDS
HYDROXY COMPOUNDS
KETO ACIDS
MEMBRANES
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANOIDS
PARASITES
PESTICIDES
PHOSPHOHYDROLASES
PLANTS
STEROIDS
STEROLS
SYNTHESIS
550200* - Biochemistry