Spermiogenesis in the Marine Shrimp, Sicyonia ingentis. (penaeidae/sperm/spermiogenesis)

Development of the mesendoderm in the dendrobranchiate shrimp Sicyonia ingentis.

Dendrobranchiate shrimp embryos form a 4-cell stage that resembles spiralians in its cell contacts, but cleavage proceeds radially without any further evidence of spiralian character. The fates of Sicyonia ingentis mesendoblasts were followed by nuclear staining and confocal microscopy. The dorsal mesendoblast produced yolk-endoderm, which proliferated from the anterior of the embryo to cover t...

Cell-cell association directed mitotic spindle orientation in the early development of the marine shrimp Sicyonia ingentis.

During early cleavages of Sicyonia ingentis embryos, mitotic spindle orientations differ between blastomeres and change in a predictable manner with each successive mitosis. From 2nd through 7th cleavages, spindles orient at a 90 degrees angle with respect to the spindle of the parent blastomere. Thus, spindle orientation is parallel to the cleavage plane that formed the blastomere. To determin...

Twin meiosis 2 spindles form after suppression of polar body 1 formation in oocytes of the marine shrimp Sicyonia ingentis.

The production of triploid shellfish has proven beneficial to the aquaculture industry since triploid organisms have reduced gonadal development, resulting in improved product quality and growth characteristics (1). Triploidization has been achieved for several molluscan species (2, 3, 4, 5, 6). In contrast, little is known about the effects of ploidy manipulation in decapod crustaceans. Triplo...

Cleavage and gastrulation in the shrimp Sicyonia ingentis: invagination is accompanied by oriented cell division.

Embryos of the penaeoidean shrimp Sicyonia ingentis were examined at intervals during cleavage and gastrulation using antibodies to beta-tubulin and DNA and laser scanning confocal microscopy. Cleavage occurred in a regular pattern within four domains corresponding to the 4-cell-stage blastomeres and resulted in two interlocking bands of cells, each with similar spindle orientations, around a c...

Short Communication: Chromosome studies on the marine shrimp Penaeus (Fenneropenaeus) merguiensis from the Persian Gulf