title: Aberration of morphogenesis of siliceous frustule elements of the diatom Synedra acus in the presence of germanic acid.
abstract: Addition of germanic acid into the culture medium of the diatom Synedra acus subsp. radians (Kutz.) Skabitsch. had nearly no influence on the culture growth at the Ge/Si molar ratio 0.01, but stopped it at ratios 0.05 and higher. It was shown by mass-spectrometry that at the Ge/Si ratio 0.01 germanium was incorporated in both the cytoplasm and siliceous valves, whereas at Ge/Si 0.05 it was incorporated into the cytoplasm but almost failed to accumulate in the valves. At Ge/Si 0.1 germanium was accumulated in the cytoplasm, but its incorporation into the valves terminated. Studies on the cell morphology by light, epifluorescence, and transmission electron microscopy showed that high concentrations of germanic acid induced disorders in morphogenesis of the siliceous frustule and accumulation of large rhodamine-stainable electron-dense inclusions. Model chemical experiments with over-saturated solutions of silicic acid in the presence of polyallylamine revealed that addition of 5% germanic acid considerably accelerated coagulation of silica. Hence, the toxic effect of germanic acid on diatoms could be caused by changes in coagulation of silica.
authors.affiliation: Limnological Institute, Siberian Branch of the Russian Academy of Sciences, Irkutsk, 664033, Russia.
authors.forename: T A
authors.initials: TA
authors.lastname: Safonova
authors.forename: V V
authors.initials: VV
authors.lastname: Annenkov
authors.forename: E P
authors.initials: EP
authors.lastname: Chebykin
authors.forename: E N
authors.initials: EN
authors.lastname: Danilovtseva
authors.forename: Ye V
authors.initials: YV
authors.lastname: Likhoshway
authors.forename: M A
authors.initials: MA
authors.lastname: Grachev
mesh_terms: D001693:Biological Transport, Active / Q000187:drug effects; D017377:Diatoms / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism* / Q000648:ultrastructure; D005857:Germanium / Q000494:pharmacology*; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D012824:Silicic Acid / Q000378:metabolism; D012825:Silicon / Q000378:metabolism; D012822:Silicon Dioxide / Q000378:metabolism*
chemical_list: D005857:Germanium; D012824:Silicic Acid; D012822:Silicon Dioxide; D012825:Silicon