Paul Gottlob Layer

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The histochemical localization of specific acetylcholinesterase (AcChoEase) and nonspecific cholinesterase (BtChoEase) is described during the early morphogenesis of the whole chicken head with main emphasis on the visual system. It is found that: (i) Expression of AcChoEase is an early differentiation event in the entire brain. Its pattern of first(More)
Müller cells are astrocyte-like radial glia cells which are formed exclusively in the retina. Here we present evidence that Müller cells are crucially involved in the development of the retina's architecture and circuitry. There is increasing evidence that Müller cells are present from the very early beginning of retinogenesis. We postulate the "gradual(More)
Cholinesterases present homologies with some cell adhesion molecules; however, it is unclear whether and how they perform adhesive functions. Here, we provide the first direct evidence showing that neurite growth in vitro from various neuronal tissues of the chick embryo can be modified by some, but not all, anticholinesterase agents. By quantifying the(More)
We have used Lucifer Yellow for histological tracing of displaced amacrine cells within the ganglion cell layer (GCL) during the embryonic development of the chicken retina. Incubating whole eyes in the dye leads to bright staining of all displaced amacrine cells, whereas ganglion cells and glial cells are not stained. A subpopulation of cells of the inner(More)
TrkA high-affinity receptors are essential for the normal development of sympathetic paravertebral neurons and subpopulations of sensory neurons. Paravertebral sympathetic neurons and chromaffin cells of the adrenal medulla share an ontogenetic origin, responsiveness to NGF, and expression of TrkA. Which aspects of development of the adrenal medulla might(More)
Close relationships between acetylcholinesterase (AcChoEase; acetylcholine acetylhydrolase, true cholinesterase, EC, 3.1.1.7) and butyrylcholinesterase (BtChoEase, acylcholine acylhydrolase, pseudocholinesterase, EC, 3.1.1.8) with cell proliferation were observed in the early chicken brain. These include the following: BtChoEase is transiently accumulating(More)
We report here that, in comparison to aggregates from retinal cells alone, addition of pigmented epithelial cells to retinal cells in rotary culture results in a pronounced increase of spatial order. A particularly high level of organization is found in about 15-20% of the aggregates. In these 'retinoids' the main layers characteristic of developing in vivo(More)
We used chicken retinospheroids (RS) to study the nuclear architecture of vertebrate cells in a three-dimensional (3D) cell culture system. The results showed that the different neuronal cell types of RS displayed an extreme form of radial nuclear organization. Chromatin was arranged into distinct radial zones which became already visible after DAPI(More)
The reaggregate approach involves the regeneration of histotypical three-dimensional spheres from dispersed cells of a given tissue in suspension culture. Reaggregated spheres are used as tumour, genetic, toxicological, biohybrid and neurosphere models, and often replace animal experimentation. A particularly instructive example is the use of reaggregation(More)
The embryonic development of total specific activities as well as of molecular forms of acetylcholinesterase (AChE, EC 3.1.1.7) and of butyrylcholinesterase (BChE, EC 3.1.1.8) have been studied in the chick brain. A comparison of the development in different brain parts shows that cholinesterases first develop in diencephalon, then in tectum and(More)