Cytoplasmic organization and compartmentalization in Drosophila early embryo syncytium

Microgravity simulation as a probe for understanding early Xenopus pattern specification

Development ◽

10.1242/dev.89.1.259 ◽

1985 ◽

Vol 89 (1) ◽

pp. 259-274

Author(s):

Anton W. Neff ◽

George M. Malacinski ◽

Hae-Moon Chung

Keyword(s):

Early Embryo ◽

Microgravity Environment ◽

Natural Phenomenon ◽

Gravity Compensation ◽

Microgravity Simulation ◽

Cytoplasmic Organization ◽

Sperm Penetration ◽

Gravity Driven ◽

Speed Rotation ◽

Pattern Specification

Pattern specification in early amphibians Xenopus) was monitored in embryos subjected to gravity compensation (microgravity simulation) by constant low-speed rotation on a horizontal axis (clinostat). The useful range of clinostat speeds was determined empirically. The results were interpreted in terms of a set of models which account for the reorganization of the egg cytoplasm that follows fertilization and that correlates with the establishment of dorsal/ventral polarity. Large percentages of clinostated eggs displayed a positive result (normal axial structure morphogenesis). Consequently, normal development of amphibian eggs in the microgravity environment of space should be possible. Models which depend upon gravity-driven rearrangements for cytoplasmic organization (e.g. dorsal/ventral polarization) of the early embryo should, therefore, not be favoured. At several clinostat speeds symmetrization of the egg in accordance with the site of sperm penetration, a natural phenomenon, was altered. The results at those clinostat speeds indicate that models which employ sperm entrance as an obligatory feature of the cytoplasmic rearrangements that generate egg polarity are not applicable.

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Cytoplasmic Organization in the Receptor Cells of the Crista Ampullaris

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100093559 ◽

1972 ◽

Vol 30 ◽

pp. 60-61 ◽

Cited By ~ 1

Author(s):

Robert F. Dunn

Keyword(s):

Fine Particles ◽

Apical Cell ◽

Apical Region ◽

Receptor Cells ◽

Cuticular Plate ◽

Morphological Organization ◽

Crista Ampullaris ◽

Cytoplasmic Organization ◽

High Degree ◽

General Appearance

Receptor cells of the cristae in the vestibular labyrinth of the bullfrog, Rana catesbiana, show a high degree of morphological organization. Four specialized regions may be distinguished: the apical region, the supranuclear region, the paranuclear region, and the basilar region.The apical region includes a single kinocilium, approximately 40 stereocilia, and many small microvilli all projecting from the apical cell surface into the lumen of the ampulla. A cuticular plate, located at the base of the stereocilia, contains filamentous attachments of the stereocilia, and has the general appearance of a homogeneous aggregation of fine particles (Fig. 1). An accumulation of mitochondria is located within the cytoplasm basal to the cuticular plate.

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Laser scanning confocal microscopic analysis of cytoskeletal and nuclear reorganization in live Drosophila embryos

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100146710 ◽

1993 ◽

Vol 51 ◽

pp. 174-175

Author(s):

William Theurkauf

Keyword(s):

Laser Scanning ◽

Microscopic Analysis ◽

Large Cell ◽

Early Embryo ◽

Drosophila Embryo ◽

Cortical Actin ◽

Nuclear Reorganization ◽

Cytoskeletal Elements ◽

Microtubule Structure ◽

Drosophila Embryos

Cell division in eucaryotes depends on coordinated changes in nuclear and cytoskeletal components. In Drosophila melanogaster embryos, the first 13 nuclear divisions occur without cytokinesis. During the final four divisions, nuclei divide in a uniform monolayer at the surface of the embryo. These surface divisions are accompanied by dramatic changes in cortical actin and microtubule structure (Karr and Alberts, 1986), and inhibitor studies indicate that these changes are essential to orderly mitosis (Zalokar and Erk, 1976). Because the early embryo is syncytial, fluorescent probes introduced by microinjection are incorporated in structures associated with all of the nuclei in the blastoderm. In addition, the nuclei divide synchronously every 10 to 20 min. These characteristics make the syncytial blastoderm embryo an excellent system for the analysis of mitotic reorganization of both nuclear and cytoskeletal elements. However, the Drosophila embryo is a large cell, and resolution of cytoskeletal filaments and nuclear structure is hampered by out-of focus signal.

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