title: Yolk protein synthesis in the riceland tadpole shrimp, Triops longicaudatus, measured by in vitro incorporation of 3H-leucine.
abstract: Investigation of reproductive control within the tadpole shrimp, Triops longicaudatus, required the isolation and characterization of the yolk protein (vitellin, Vn). To this end, tadpole shrimp were cultured in environmental chambers (29 degrees C-22 degrees C, with 14:10 light:dark cycle). Desiccated cysts hatched in 2-3 days after inundation. The tadpole shrimp began egg deposition 7 to 8 days after hatching and exhibited a mean growth rate of 1.85 +/- 0.24 mm/day. It was observed that 4-day-old shrimp had visible eggs in their ovaries. In addition, Vn was isolated and characterized from reproductive animals, resolving as one protein on native PAGE, and possessing a molecular weight (MW) of 376,000 +/- 2,900 as determined by FPLC. Examination by SDS-PAGE revealed that Vn is composed of a single molecule with a MW of 214,000 +/- 2,000. Methyl farnesoate (MF), a crustacean compound whose role in reproduction is still being elucidated and is structurally similar to juvenile hormone III (JH III) was incubated with ovarian explants. These explants were incubated for 24 h at room temperature in EAGLE's medium adjusted to Van Harreveld's solution in six concentrations (1 pM to 100 nM) of MF and JH III. Methyl farnesoate and JH III had no direct in vitro effect on yolk protein synthesis (P < or = 0.545 and P < or = 0.815, respectively).
authors.affiliation: Department of Biology, California State University, Fresno 93740, USA.
authors.forename: L G
authors.initials: LG
authors.lastname: Riley
authors.forename: B
authors.initials: B
authors.lastname: Tsukimura
mesh_terms: D000818:Animals; D033364:Decapoda / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D004527:Egg Proteins / Q000096:biosynthesis* / Q000276:immunology / Q000302:isolation & purification / Q000378:metabolism; D005260:Female; D066298:In Vitro Techniques; D007605:Juvenile Hormones / Q000378:metabolism; D007930:Leucine / Q000378:metabolism*; D010053:Ovary / Q000187:drug effects; D010063:Ovum / Q000254:growth & development / Q000502:physiology; D012098:Reproduction / Q000502:physiology*; D014316:Tritium
chemical_list: D004527:Egg Proteins; D007605:Juvenile Hormones; D014316:Tritium; D007930:Leucine