Types and distribution of lamellar bodies in first cleavage Xenopus embryos.

Lamellar bodies in first cleavage Xenopus laevis embryos have been examined with the electron microscope. Based on the arrangement and relative thickness of the lamellae, three types of lamellar bodies have been identified. In the first type, a band of two to ten lamellae (spacing about 3.5 nm) was interwined at random. This type of lamellar body was seen closely associated with the concave or the forming face of the Golgi body and may have been derived from this organelle. The frequent association of these lamellar bodies with the growing cleavage furrow may suggest a transfer of materials from the Golgi body to the furrow through the lamellar bodies or their precursors. In the second type, typical myelin-like figures with a repeating distance of about 10 nm were located close to the furrow tip. In the third type, membrane whorls containing tetrads of lamellae (approximately 16 nm thickness) were seen associated with lipid droplets. If the lamellar bodies observed in this study were formed during fixation then the appearance of three different types after the same fixation procedure would indicate the presence of a similar number of pools of precursor materials which differ in their chemical composition and distribution in the embryo.