title: Bouyant density of the DNA of sea urchin embryos at different stages of development.
abstract: Preparations of high-molecular nuclear DNA were obtained from embroys of the sea urchin Strongylocentrotus droebachiensis at the stages of early and late blastula, gastrula, and pluteus. In an equilibrium cesium chloride density gradient, these preparations exhibit a single narrow symmetrical band at 1.695-1.703 g/cm3 with a maximum at l.699 plus or minus 0.001 g/cm3 and do not contain satellite components. Nuclear DNA of embroys at the stage of 128 blastomeres (morula), which has a molecular weight of 10-6, exhibits a single broad symmetrical band at 1.690-1.710 g/cm3 with a maximum at 1.699 g/cm3 in a density gradient. Fragments of blastula and pluteus DNA obtained as a result of treatment with ultrasound give an analogous distribution. Preparations of total DNA of unfertilized ovicells, total DNA of spermatozoids, and cytoplasmic DNA of the morula contain satellite components with buoyant densities of 1.717-1.725 g/cm3 side by side with the main band.
mesh_terms: D000818:Animals; D002455:Cell Division; D002467:Cell Nucleus / Q000032:analysis; D002499:Centrifugation, Density Gradient; D004247:DNA; D004625:Embryo, Nonmammalian / Q000032:analysis; D005260:Female; D005306:Fertilization; D008297:Male; D008970:Molecular Weight; D012617:Sea Urchins / Q000032:analysis*; D013094:Spermatozoa / Q000032:analysis; D013997:Time Factors; D014465:Ultrasonics
chemical_list: D004247:DNA