细胞技术

The processes of dying are as tightly regulated as those of growth and proliferation. Recent work into the molecular pathways that regulate and execute cell death have uncovered a plethora of signalling cascades that lead to distinct modes of cell death, including “apoptosis,” “necrosis,” “ ...

Apoptosis and necrosis reflect the program of cell death employed by a dying cell and the final stage of death, respectively. Whereas apoptosis is defined as a physiological, highly organized cell death process, necrosis is commonly considered to be accidental and uncontrolled. Physiol ...

The development of such techniques as transgenesis, saturation mutagenesis, and the polymerase chain reaction (PCR), all of which are described in detail elsewhere in this volume, has revolutionized experimental embryology. However, no single procedure has been more broadly appl ...

Antisense oligodeoxynucleotides are being widely used to interfere with specific gene activities in cell-culture systems (1,2), and there are possible analytical advantages to partial and timed interference in the whole embryo, for certain genes, as compared with targeted null mut ...

The regulation of complex developmental pathways involves the spatial and temporal interaction of specific gene products. Several powerful genetic approaches, including the tagging of gene products or cells, have allowed their distribution in space and time to be determined. The ad ...

Soon after Spemann and Mangold’s (1) famous demonstration in 1924 that the dorsal lip of the blastopore of the gastrulating amphibian embryo has the unique ability to induce a second axis when grafted into an ectopic site in a host embryo, Waddington (2,3) showed that Hensen’s node is its equivalent in a ...

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 ...