细胞功能测定

The following methods comprise a brief description of chick egg incubation and embryo harvesting. For further details concerning optimizing embryo viability during incubation, the reader is referred to the excellent work of New (1). Embryos are staged according to the staging series de ...

Many patterning structures have been identified by microsurgical manipulation of chick embryos in ovo, such as ablation or heterotopic grafting experiments. Among the structures studied, the notochord has received much attention, since it plays a crucial role in the development of the ...

The use of microinjection to study gene function in the zebrafish has become widespread in recent years. This includes ectopic expression of genes by introducing DNA (1) or RNA into embryos or injection of blocking molecules, such as RNA encoding truncated proteins (2) or antibodies, to perturb ...

During the past 10 yr, the zebrafish has emerged as an important model system for the study of vertebrate development. This is primarily because of the promise of the system for developmental genetic studies. but, in addition to the necessary features of an animal that can be used for genetics, there are a ...

The retinoids comprise a large group of natural and synthetic compounds related to vitamin A (retinol). The family name is derived from the early observation of the necessity of vitamin A for normal vision, and the association of vitamin A deficiency with night blindness (1). With the exception of t ...

The development of transgenic technology during recent years has allowed researchers to probe much more deeply than was previously possible into the molecular mechanisms influencing embryonic development. Transgenic procedures allow the transfer of a cloned gene into a host gen ...

The understanding of several mechanisms that are essential for embryonic development has greatly benefited from cell-marking techniques that allow tracing of definite cells and their progeny, and thus, the study of their behavior and fate. A cell marker must be precise and stable; it must not ...

In situ hybridization (ISH) takes advantage of the ability of mRNA within a cell to hybridize with exogenously applied complementary RNA (riboprobes) or DNA molecules. This interaction is visualized by labeling the applied nucleic acid probe with a detectable molecule (radioactive, s ...

As indicated in the preceding chapter, few techniques have had such a major impact on progress in the field of developmental biology as in situ hybridization of labeled RNA or DNA probes to detect specific mRNAs in embryonic tissues. Initially, the technique was performed on sections of fixed mat ...

Highly proliferative cells including stem cells and cancer cells express high levels of telomerase, an enzyme activity that adds a six-base DNA repeat sequence (TTAGGG) to chromosome ends and thereby prevents their shortening during successive rounds of mitosis (1,2). Telomerase act ...

The majority of studies centered on understanding the in vitro properties of olfactory ensheathing glia (OEG) have utilized OEG prepared from the nerve fiber layer of the embryonic or neonatal olfactory bulb (1–3), summarized in chapter 4. In fact, a significant fraction of the OEG population is ...

The ability to produce highly purified populations of individual cell types is crucial for examining the molecular regulation of cell growth, differentiation, and function. Olfactory ensheathing cells (OECs) are also known as olfactory ensheathing glia (OEG) and olfactory nerve e ...

Neurons and glial cells of the forebrain arise ultimately from a pseudostratified ventricular epithelium (PVE), which lines the ventricular margins of the embryonic cerebral vesicles (1). Neurons that undergo their terminal mitosis in this epithelium migrate directly to the target ...

Tissue engineering has arisen to address the extreme shortage of tissues and organs for transplantation and repair. One of the most successful techniques has been the seeding and culturing of cells on three-dimensional biodegradable scaffolds in vitro followed by implantation in vivo ...

The generation of neuronal and glial cell types found in the mature central nervous system (CNS) involves the massive proliferation of ventricular zone cells of the fetal brain and spinal cord (1) that stop dividing early in development and terminally differentiate. Most neurons in the adult ...

Neural crest cells migrate from the dorsal aspect of the neural tube and differentiate into a variety of cell types in different locations. These cell types include peripheral neurons and glia (Schwann cells), melanocytes, endocrine cells, smooth muscle, skeletal muscle and bone (1). In vivo l ...

Development of the brain is a complex set of events beginning at the time that the fate of embryonic cells is decided. Once chosen, these cells proceed on their migratory track, which brings them to the brain regions in which they reside and settle down. Here, the cells differentiate into array of distinct ...

Direct surgical access to the mammalian embryo is made difficult by its protected position, enclosed in the uterus within the decidua and the embryonic membranes. This condition historically favored the development of experimental embryology in submammalian species like newts, f ...

For most of the history of neuroscience, it was widely believed, despite isolated reports to the contrary (1), that de novo generation of neurons in the mammalian CNS did not persist past perinatal development. It was not until the last decade of the twentieth century that the existence, within the CNS of ...

Differentiation of pluripotent embryonic stem (ES) cells into specific lineages is an important source of cells for implantation and gene delivery, as well as a useful model to study patterns of differentiation and gene expression during the very early development of the mammalian embryo ...