D. R. Garrod – författare

1. 1. Aspects of development. usually competent to develop in several differ- If you have been fortunate enough to see a fIlm ent ways. Thus the mesenchyme cells of the of the development of any multicellular organ- embryonic chick limb bud may become, among ism or, better still, to watch live embyros devel- other things, muscle or cartilage cells. Differen- oping, the intricate beauty of the developmental tiation is largely an intracellular process involv- process will not have escaped you: nor will its ing the appearance of cells with certain bio- complexity. Apparent complexity, however, is chemically or cytologically recognizable charac- no reason for despair when one begins to think teristics through the differential activation of in terms of analysing development. Rather, it is genes whose products confer these character- istics on the cello In skeletal muscle cells for astimulus to the first and most important ana- lytical step, that of simplifying the problem by example, specific proteins (actin and myosin) dividing it into aspects which can be meaning- are synthesized, and arranged to give the typical fully studied. striated appearance (Fig. l. la).(Differentiation is the subject of another book in this series, The most obvious way to divide development is on a chronological basis - to begin with ferti- 'Cell Differentiation' by J. M. Ashworth. ) lization and proceed through cleavage, blastu- Recent advances in molecular biology have greatly stimulated research into differentiation lation and gastrulation to organ fromation.

The complementary binding of a ligand and receptor is the basic language of intercellular communication and this book takes a broad look at the current status of research on receptors in higher and lower plants. It starts with a discussion of some hormone receptors (auxins, ethylene and gibberellin) in higher plants, and then considers the role of cyclic AMP and its receptors in the slime mould Dictyostelium. Authoritative accounts of our present knowledge of several 'adhesive' phenomena are also given. These include fertilization in higher plants and yeasts, the infection of protoplasts by pathogens and of root hairs by nitrogen-fixing bacteria, cell-cell adhesion in Dictyostelium and a general consideration of the functions of lectins. First published in 1986, this book will be valuable to biochemists, cell biologists and physiologists at the research level.

The aim of "The Adhesive Interaction of Cells" has been to assemble a series of reviews by leading international experts embracing many of the most important recent developments in this rapidly expanding field. The purpose of all biological research is to understand the form and function of living organisms and, by comprehending the normal, to find explanations and remedies for the abnormal and for disease conditions. The molecules involved in cell adhesion are of fundamental importance to the structure and function of all multicellular organisms. In this book, the contributors focus on the systems of vertebrates, especially mammals, since these are most relevant to human disease. It would have been equally possible to concentrate on developmental processes and adhesion in lower organisms. A major function of adhesion molecules is to bind cells to each other or to the extracellular matrix, but they are much more than "glue". Adhesions in animal tissues must be dynamic-forming, persisting, or declining in regulated fashion- to facilitate the mobility and turnover of tissue cells. Moreover, the majority of adhesion molecules are transmembrane molecules and thus provide links between the cells and their surroundings. This gives rise to another major function of adhesion molecules, the capacity to transduce signals across the hydrophobic barrier imposed by the plasma membrane. Such signal transduction is crucially important to many aspects of cellular function including the regulation of cell motility, gene expression, and differentiation. The work in this book progresses through four sections. Part I discusses the four major families of adhesion molecules themselves, the integrins (Green and Humphries), the cadherins (Stappert and Kemler), the selectins (Tedder et al.) and the immunoglobulin superfamily (Simmons); part 2 considers junctional complexes involved in cell interactions: focal adhesions and adherens junctions (Ben Ze'ev), desmosomes (Garrod et al.), and tight junctions (Citi and Cordenonsi). The signaling role of adhesion molecules is the focus of part 3, through integrins and the extracellular matrix (Edwards and Streuli), through platelet adhesion (Du and Ginsberg), and in the nervous system (Hemperley). In part 4, the aim is to show how adhesive phenomena contribute to important aspects of cell behavior and human health. Leukocyte trafficking (Haskard et al.), cancer metastasis (Marshall and Hart), cell migration (Paleck et al.), and implantation and placentation (Damsky et al.) are the topics considered in depth.The different sections are, of course, not mutually exclusive: it is both undesirable and impossible to separate structure from function when considering cell adhesion. Each chapter has its unique features, but some overlap is both invevitable and valuable since it provides different perspectives on closely related topics. We hope that the whole contributes a valuable and stimulating consideration of this important topic.