title: Dietary tocopherol and sexual reproduction in the rotifers Brachionus calyciflorus and Asplanchna sieboldi.
abstract: Brachionus calyciflorus contained no detectable tocopherol (vitamin E) when cultured for long periods on the yeast Rhodotorula glutinis. Using a spectrofluorometric assay and the Asplanchna body-wall-outgrowth response bioassay the limits of detection were 6.4 ng and 3.78 pg alpha-tocopherol per g dry weight Brachionus, respectively. These tocopherol-free Brachionus reproduced normally both parthenogenetically and sexually, producing active and potent males and fertilized resting eggs which developed  into viable young rotifers. The apparent lack of a tocopherol requirement for male fertility in B. calyciflorus probably also applies to Asplanchna sieboldi and A. brightwell -- rotifers whose male-producing (mictic) females are induced by dietary tocopherol and whose males therefore are never tocopherol-deficient. The adaptive significance of the tocopherol requirement for the initiation of sexual reproduction in Asplanchna sieboldi--formerly hypothesized to be the result of a tocopherol requirement for male fertility--is now thought to be related to the role of tocopherol in controlling female polymorphism in this species.
mesh_terms: D000818:Animals; D001681:Biological Assay; D003470:Culture Media; D005260:Female; D007448:Invertebrates / Q000378:metabolism / Q000502:physiology*; D008297:Male; D010312:Parthenogenesis; D010933:Plankton / Q000502:physiology*; D012098:Reproduction; D012248:Rhodotorula; D014810:Vitamin E / Q000378:metabolism*; D015048:Zooplankton / Q000378:metabolism / Q000502:physiology*
chemical_list: D003470:Culture Media; D014810:Vitamin E