Colin RJ Phillips

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It has long been thought that anteroposterior (A-P) pattern in the vertebrate central nervous system is induced in the embryo's dorsal ectoderm exclusively by signals passing vertically from underlying, patterned dorsal mesoderm. Explants from early gastrulae of the frog Xenopus laevis were prepared in which vertical contact between dorsal ectoderm and(More)
Epi 1, a monoclonal antibody, was generated against an epidermal specific epithelial antigen; it does not stain neural epithelium. We have used Epi 1 as a marker to determine when the spatial patterns delineating neural from nonneural epithelium become established. We used ventral ectoderm in a sandwich assay to show that signals from the central blastopore(More)
Xenopus laevis embryos were oriented and sectioned into six regions along one of three axes: animal-vegetal, dorsal-ventral, or right-left. Total RNA (predominantly ribosomal RNA) and poly riboadenylate [poly (A)] were measured for each region during early embryogenesis. The concentrations of both total RNA and poly(A) are nonuniformly distributed during(More)
Dorsal-ventral axis formation in Xenopus laevis begins with a cytoplasmic rotation during the first cell cycle and culminates in a series of cell interactions and movements during gastrulation and neurulation that lead to the formation of dorsal-anterior structures. Evidence reported here indicates that mitochondria are differentially redistributed along(More)
The induction of morphologically observable neural structures occurs as the result of tissue interactions between chordamesoderm and overlying ectoderm beginning at gastrulation. Since the future dorsal, and hence neural, side of the embryo is determined around the time of fertilization, we questioned whether the presumptive neural epithelium might have(More)
A monoclonal antibody (Epi 1) has been produced that recognizes an antigen expressed in epidermal cells of Xenopus laevis embryos. The Epi 1 antigen appears in embryonic epidermis at the end of gastrulation and is not expressed in nonepidermal structures derived from ectoderm (for example, neural tube or cement gland). The capacity to express the Epi 1(More)
With the advent of space travel, it is of immediate interest and importance to study the effects of exposure to various aspects of the altered environment of space, including microgravity, on Earth-based life forms. Initial studies of space travel have focused primarily on the short-term effects of radiation and microgravity on adult organisms. However,(More)
The dorsal-ventral axis of the Xenopus embryo is approximately determined by the point of sperm entry, which occurs randomly about the animal-vegetal axis of the egg. Two cytoplasmic components were studied whose spatial arrangements and local concentration patterns appear to reflect the forming dorsal-ventral axis. First, three-dimensional maps depicting(More)
invited speaker: irene Tracey nuffield Professor anaesthetic science & director, oxford centre for fMri of Brain, nuffield department of clinical neurosciences, (head, nuffield division anaesthetics), oxford university, england, uK The ability to experience pain is old and shared across species. It confers an evolutionary advantage and provides a warning of(More)
The study of neural induction in Xenopus can be approached from two broad perspectives. One can study the competence of the ectoderm to respond to neural induction signals and any potential prepattern within the ectoderm. The second area of study involves the neural induction signals, in terms of the chemical nature of the signals, their sources, and their(More)
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