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Published on: August 16, 2019
Scanning Electron microscopic Study on the Early Development of Silkworm Eggs (Bombyx mori L.): (silkworm/early
Hiroomi Keino1, Sachiko Takesue2
1Department of Perinatology, Institute for Developmental Research, Kasugai, Aichi 480-03, Japan.
Abstract:
Morphological changes of the surface of eggs of the silkworm Bombyx mori L. were studied during early developmental stages by scanning electron microscopy. The egg surface was covered with numerous microvilli at least until 4 h after oviposition. At 6 h the microvilli were replaced by ruffle-like microprojections. This suggests that developmental changes of the surface structure may occur without direct influence of cleavage nuclei. Immediately before blastoderm cell formation, microvilli reappeared in the presumptive groove area. The ruffles seen on the apical portion of newly-formed blastoderm cells gradually became flattened, while microvilli developed on the lateral side of the cells. The mode of blastoderm cell formation is different from the typical one seen in most species of insects.
Insights
Surface changes in silkworm Bombyx mori eggs occur early, with microvilli transforming into ruffles and reappearing before blastoderm formation. These morphological shifts suggest early development independent of cleavage nuclei.
Area of Science:
- Developmental Biology
- Cell Biology
- Entomology
Background:
- The silkworm Bombyx mori egg undergoes significant early developmental changes.
- Understanding surface morphology is crucial for comprehending early embryonic development in insects.
Purpose of the Study:
- To investigate the dynamic morphological alterations of the Bombyx mori egg surface during early developmental stages.
- To correlate surface structure changes with key developmental events like cleavage and blastoderm formation.
Main Methods:
- Scanning electron microscopy (SEM) was utilized to visualize the egg surface.
- Eggs were examined at specific time points post-oviposition, including 4 h and 6 h, and immediately before blastoderm formation.
Main Results:
- The egg surface initially displayed numerous microvilli, persisting until at least 4 hours post-oviposition.
- By 6 hours, microvilli were replaced by ruffle-like microprojections, indicating a significant surface transformation.
- Microvilli reappeared in the presumptive groove area before blastoderm cell formation, and blastoderm cells showed distinct apical and lateral surface features.
Conclusions:
- Early surface structural changes in Bombyx mori eggs may occur independently of cleavage nuclei influence.
- The observed pattern of blastoderm cell formation in Bombyx mori differs from the typical insect mode, highlighting unique developmental pathways.
