title: Changes in the chemical composition of oospores of Pythium aphanidermatum during bimodal germination.
abstract: The developmental mode by which oospores of Pythium aphanidermatum germinate may be controlled by the concentration of glucose present in the germination medium. When incubated in a liquid medium containing emulsified lecithin without added glucose (S + L), oospores germinated indirectly, with zoospore release occurring during the 10th to 13th h. A decrease in dry weight of the fungus took place by the 13th h of indirect germination. When 0.2 mM glucose was added to S + L, the dry weight of germlings increased and direct germination occurred without zoospore formation. Polar lipid comprised the bulk of total acylglycerides of dormant oospores. A greater decrease in total fatty acid content took place during direct germination than during indirect germination. During both developmental modes of germination, polar lipid content decreased considerably; neutral lipids, however, increased during indirect germination and decreased during direct germination. Protein content of the fungus increased in both developmental modes of germination, being initially 9.7% of the dry weight of dormant oospores. After 13 h of incubation, KOH-soluble polysaccharide decreased by 35% during direct germination and by 48% during indirect germination.
mesh_terms: D005227:Fatty Acids / Q000378:metabolism; D005656:Fungal Proteins / Q000378:metabolism*; D005658:Fungi / Q000378:metabolism*; D050356:Lipid Metabolism; D011134:Polysaccharides / Q000378:metabolism*; D011775:Pythium / Q000254:growth & development / Q000378:metabolism*; D013172:Spores, Fungal
chemical_list: D005227:Fatty Acids; D005656:Fungal Proteins; D011134:Polysaccharides