title: Effect of mixotrophic growth on the ultrastructure and fatty acid composition of the diatom Synedra acus from Lake Baikal.
abstract: BACKGROUND
  Interest in studies concerning the effect of organic carbon sources on the growth of diatoms is largely aimed at subsequent physiological changes occurring in their cells. There are no data on structural changes in the cytoplasm and their relationship with changes in the composition of fatty acids in the course of mixotrophic culturing of freshwater diatoms. To elucidate the role of lipids in the growth of diatom cells in autotrophic and mixotrophic cultures, it is necessary to obtain information on the distribution of fatty acids among intracellular compartments and on possible ultrastructural changes in the cells.
  
  
  RESULTS
  In this study, the results demonstrated that Synedra acus cells cultured in the presence of 80 mM glycerol contained lipid bodies of increased size, while cells from cultures supplemented with 40 mM glucose accumulated polysaccharide (chrysolaminarin) granules. An increase in the relative amounts of palmitic and stearic acids was revealed at the exponential growth phase of S. acus in the medium with 80 mM glycerol, which was indicative of the accumulation of fatty acids contained in triacylglycerols.
  
  
  CONCLUSIONS
  Synedra acus subsp. radians have an ability to proliferate in the presence of high concentrations of organic substances and their transport into cells is evidence for its high adaptation potential, which, along with other factors, accounts for the dominance of this diatom in the spring-summer plankton of the oligotrophic Lake Baikal.
authors.affiliation: Limnological Institute, Siberian Branch, Russian Academy of Sciences, 3, Ulan-Batorskaya, St, P.O. Box 278, Irkutsk, 664033 Russia.
authors.forename: Sergey M
authors.initials: SM
authors.lastname: Shishlyannikov
authors.affiliation: Limnological Institute, Siberian Branch, Russian Academy of Sciences, 3, Ulan-Batorskaya, St, P.O. Box 278, Irkutsk, 664033 Russia.
authors.forename: Igor V
authors.initials: IV
authors.lastname: Klimenkov
authors.affiliation: Limnological Institute, Siberian Branch, Russian Academy of Sciences, 3, Ulan-Batorskaya, St, P.O. Box 278, Irkutsk, 664033 Russia.
authors.forename: Yekaterina D
authors.initials: YD
authors.lastname: Bedoshvili
authors.affiliation: Limnological Institute, Siberian Branch, Russian Academy of Sciences, 3, Ulan-Batorskaya, St, P.O. Box 278, Irkutsk, 664033 Russia.
authors.forename: Ivan S
authors.initials: IS
authors.lastname: Mikhailov
authors.affiliation: Limnological Institute, Siberian Branch, Russian Academy of Sciences, 3, Ulan-Batorskaya, St, P.O. Box 278, Irkutsk, 664033 Russia.
authors.forename: Alexander G
authors.initials: AG
authors.lastname: Gorshkov
keywords: Fatty acids; GC-MS; Lake Baikal; Lipid bodies; Synedra acus; Ultrastructure