The blastulae of unincubated eggs of the quail, Coturnix coturnix japonica, have been bisected in ovo, using the technique of Lutz (1949). Some embryos were harvested after 24 h and found to possess two primitive streaks. Most were fixed at 48 h or 72 h. Some were found to have regulated to form almost normal single axes, whilst others had developed into duplicitas anterior embryos, separate tw...

Copepods from the genus Calanus provide an important lipid-rich food source in Arctic marine foodweb. Despite extensive research on finmarchicus and glacialis , accurately identifying adults to species level remains challenging due similar morphologies. Although these co-occur many regions, distribution of C. correspond Atlantic water masses respectively are frequently used as climate indicator...

The aim of this work was to investigate the role played by the axial organs, neural tube and notochord, on the differentiation of muscle cells from the somites in the avian embryo. Two of us have previously shown that neuralectomy and notochordectomy is followed by necrosis of the somites and consecutive absence of vertebrae and of most muscle cells derived from the myotomes while the limbs dev...

Somites are blocks of mesoderm [4] that are located on either side of the neural tube [5] in the developing vertebrate embryo. Somites are precursor populations of cells that give rise to important structures associated with the vertebrate body plan and will eventually differentiate into dermis, skeletal muscle, cartilage, tendons, and vertebrae. Somites also determine the migratory paths of ne...

Important advances have been made in understanding the genetic processes that control skeletal muscle formation. Studies conducted on quails detected a delay in the myogenic program of animals selected for high growth rates. These studies have led to the hypothesis that a delay in myogenesis would allow somitic cells to proliferate longer and consequently increase the number of embryonic myobla...

Somites are blocks of mesoderm [4] that are located on either side of the neural tube [5] in the developing vertebrate embryo. Somites are precursor populations of cells that give rise to important structures associated with the vertebrate body plan and will eventually differentiate into dermis, skeletal muscle, cartilage, tendons, and vertebrae. Somites also determine the migratory paths of ne...

During the embryonic development of vertebral cartilages, cells from the somite mesoderm differentiate into chondrocytes around the spinal cord and notochord. Grafting experiments in amphibian and chick embryos have indicated that the spinal cord and notochord have some influence on this differentiation of somite cells to cartilage (Holtzer & Detwiler, 1953; Watterson, Fowler & Fowler, 1954). F...

Neural crest cells in the trunk of vertebrate embryos have a choice of pathways after emigrating from the neural tube: they can migrate in either the medial pathway between somites and neural tube, or the lateral pathway between somites and epidermis. In zebrafish embryos, the first cells to migrate all choose the medial pathway. High resolution imaging of cells in living embryos suggests that ...

The blastulae of unincubated eggs of the quail, Coturnix coturnix japonica, have been bisected in ovo, using the technique of Lutz (1949). Some embryos were harvested after 24 h and found to possess two primitive streaks. Most were fixed at 48 h or 72 h. Some were found to have regulated to form almost normal single axes, whilst others had developed into duplicitas anterior embryos, separate tw...