Results 161 to 170 of about 5,285 (203)

Asymmetry of Larval Amphioxus

Nature, 1951
The evidence for the theory that Amphioxus is “essentially a paedomorphic transformation of a sessile Protascidian” is even stronger to-day than when Garstang1 first proposed it. The more recent of Conklin's investigations2 have shown the early development of Amphioxus to be “more strikingly like that of Ascidians than has been recognized hitherto ...
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Gene regulation in amphioxus: An insight from transgenic studies in amphioxus and vertebrates

Marine Genomics, 2015
Cephalochordates, commonly known as amphioxus or lancelets, are the most basal subphylum of chordates. Cephalochordates are thus key to understanding the origin of vertebrates and molecular mechanisms underlying vertebrate evolution. The evolution of developmental control mechanisms during invertebrate-to-vertebrate transition involved not only gene ...
Iryna, Kozmikova, Zbynek, Kozmik
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On the Spinal Nerves of Amphioxus

Journal of Cell Science, 1880
ABSTRACT In an interesting memoir devoted to the elucidation of a series of points in the anatomy and development of the Vertebrata, Schneider1 has described what he believes to be motor nerves in Amphioxus, which spring from the anterior side of the spinal cord.
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The embryology of amphioxus

Journal of Morphology, 1932
AbstractAlthough the egg of Amphioxus is much more fluid and less stereotyped than that of Ascidians, the poles, axes, and localizations of formative materials are much the same in the two. The spermatozoon enters near the vegetative pole and a peripheral layer of granular cytoplasm flows to this pole and later forms a crescent around the posterior ...
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Paramyosin Muscle in the Notochord of Amphioxus

Nature, 1969
As is evident from every textbook of zoology, the internal skeleton or notochord of amphioxus (Branchiostoma lanceolatum) has been considered as a passive supporting organ by all but a very few investigators. Our examination, using modern techniques, however, supports the view of Ebner1 and Joseph2, who proposed a muscular nature of the notochord (Fig.
P R, Flood, D M, Guthrie, J R, Banks
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Fine structure of photoreceptors in amphioxus

Journal of Ultrastructure Research, 1962
The cells of Hesse in the ventral wall of the neural tube of Amphioxus, long assumed to be photoreceptors, were found by electron microscopy to possess many narrow irregular tubules, or diverticula of the cell membrane, immediately adjacent to the melanocyte associated with each receptor cell. Cilium-like structures are absent. Accordingly, Hesse cells
R M, EAKIN, J A, WESTFALL
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Developmental expression of amphioxus RACK1

Science in China Series C: Life Sciences, 2007
Vertebrate RACK1 plays a key role in embryonic development. This paper described the cloning, phylogenetic analysis and developmental expression of AmphiRACK1, the RACK1 homologous gene in amphioxus. Phylogenetic analysis indicated that amphioxus RACK1 was located at the base of vertebrate clade.
XiangWei, Huang, Wei, Zhang, XinYi, Li, XiaoHui, Zhang, BaoJun, Li, BingYu, Mao, HongWei, Zhang   +6 more
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Early development of cephalochordates (amphioxus)

WIREs Developmental Biology, 2011
AbstractThe Phylum Chordata includes three groups—Vertebrata, Tunicata, and Cephalochordata. In cephalochordates, commonly called amphioxus or lancelets, which are basal in the Chordata, the eggs are small and relatively non‐yolky. As in vertebrates, cleavage is indeterminate with cell fates determined gradually as development proceeds. The oocytes are
Linda Z, Holland, Takayuki, Onai
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Enzyme variability in the protochordate amphioxus

Nature, 1975
COMPARING protein polymorphisms in 24 species of invertebrates and 22 species of vertebrates, Selander and Kaufman1 observed greater genetic variability on average in the invertebrate than in the vertebrate by three criteria: number of polymorphic loci (25–50% in invertebrates compared with 10–20% in vertebrates); mean heterozygosity per locus per ...
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The Fox and the thyroid: The amphioxus perspective

BioEssays, 2002
AbstractThe evolutionary origins of several vertebrate organs are still controversial. The thyroid is classically thought to derive directly from the endostyle (a pharyngeal organ found in urochordates, cephalochordates and lampreys). Several molecular and biochemical lines of evidence agree with this scenario.
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