The process whereby a single cell, the fertilized egg, develops into an adult has fascinated for centuries. Great progress in understanding that process, h- ever, has been made in the last two decades, when the techniques of molecular biology have become available to developmental biologists. By applying these techniques, the exact nature of many of the interactions responsible for forming the body pattern are now being revealed in detail. Such studies are a large, and it seems ever-expanding, part of most life-science groups. It is at newcomers to this field that this book is primarily aimed. A number of different plants and animals serve as common model org- isms for developmental studies. In Molecular Methods in Developmental Bi- ogy: Xenopus and Zebrafish, a range of the molecular methods applicable to two of these organisms are described, these are the South African clawed frog, Xenopus laevis, and the zebrafish, Brachydanio rerio. The embryos of both of these species develop rapidly and externally, making them particularly suited to investigations of early vertebrate development. However, both Xenopus and zebrafish have their own advantages and disadvantages. Xenopus have large, robust embryos that can be manipulated surgically with ease, but their pseudotetraploidy and long generation time make them unsuitable candidates for genetics. This disadvantage may soon be overcome by using the diploid Xenopus tropicalis, and early experiments are already underway. The transp- ent embryos of zebrafish render them well-suited for in situ hybridization and immunohistochemistry, and good for observing mutations in genetic screens.

Most people have some interest in embryos; this probably results, in part, from their interest in understanding the biological origins of themselves and their offspring and, increasingly, concerns about how environmental change such as pollution might affect human development. Obviously, et- cal considerations preclude experimental studies of human embryos and, c- sequently, the developmental biologist has turned to other species to examine this process. Fortunately, the most significant conclusion to be drawn from the experimental embryology of the last two decades is the manner in which orthologous or closely related molecules are deployed to mediate similar - velopmental processes in both vertebrates and invertebrates. The molecular mechanisms regulating processes fundamental to most animals, such as axial patterning or axon guidance, are frequently conserved during evolution. (It is now widely believed that the differences between phyla and classes are the result of new genes, arising mostly by duplication and divergence of extant sequences, regulating the appearance of derived characters. ) Other vertebrates are obviously most likely to use the same devel- mental mechanisms as humans and, within the vertebrate subphylum, the - parent degree of conservation of developmental mechanism is considerable. It has long been recognized that particular vertebrate species offer either d- tinct advantages in investigating particular stages of development or are - pecially amenable to particular manipulations. No single animal can provide all the answers because not all types of experiments can be carried out on a single species.

The new edition of this popular book emphasizes the decisions that need to be made to select one procedure over another.

This manual is an indispensable tool for introducing advanced undergraduates and beginning graduate students to the techniques of recombinant DNA technology, or gene cloning and expression. The techniques used in basic research and biotechnology laboratories are covered in detail. Students gain hands-on experience from start to finish in subcloning a gene into an expression vector, through purification of the recombinant protein. The third edition has been completely re-written, with new laboratory exercises and all new illustrations and text, designed for a typical 15-week semester, rather than a 4-week intensive course. The "project approach to experiments was maintained: students still follow a cloning project through to completion, culminating in the purification of recombinant protein. It takes advantage of the enhanced green fluorescent protein - students can actually visualize positive clones following IPTG induction. - Cover basic concepts and techniques used in molecular biology research labs - Student-tested labs proven successful in a real classroom laboratories - Exercises simulate a cloning project that would be performed in a real research lab - "Project" approach to experiments gives students an overview of the entire process - Prep-list appendix contains necessary recipes and catalog numbers, providing staff with detailed instructions

Scientific Frontiers in Developmental Toxicology and Risk Assessment reviews advances made during the last 10-15 years in fields such as developmental biology, molecular biology, and genetics. It describes a novel approach for how these advances might be used in combination with existing methodologies to further the understanding of mechanisms of developmental toxicity, to improve the assessment of chemicals for their ability to cause developmental toxicity, and to improve risk assessment for developmental defects. For example, based on the recent advances, even the smallest, simplest laboratory animals such as the fruit fly, roundworm, and zebrafish might be able to serve as developmental toxicological models for human biological systems. Use of such organisms might allow for rapid and inexpensive testing of large numbers of chemicals for their potential to cause developmental toxicity; presently, there are little or no developmental toxicity data available for the majority of natural and manufactured chemicals in use. This new approach to developmental toxicology and risk assessment will require simultaneous research on several fronts by experts from multiple scientific disciplines, including developmental toxicologists, developmental biologists, geneticists, epidemiologists, and biostatisticians.

Plants come in myriads of shapes and colors, and the beauty of plants has fascinated mankind for thousands of years. Long before Mendel discovered the laws of heritab- ity and Darwin developed his theory on evolution, the affection for ornamental plants led people to select alleles that establish novel plant forms. Today, plant developmental biology tries to discover the mechanisms that control the establishment of specialized cell types, tissues, and organs from the fertilized egg during a plant’s life. Although the underlying processes of cell proliferation and differentiation are similar in plants and a- mals, plants are different because their development is usually open, and its outcome is not the faithful repetition of a general plan but is strongly in?uenced by environm- tal conditions. In the last few decades, plant developmental biology has pinpointed a large number of developmental regulators and their interactions and the mechanisms that govern plant development start to emerge. In part, this progress was enabled by the advance of powerful molecular tools for a few model species, most importantly Arabidopsis. This volume of the Methods in Molecular Biology series provides a collection of protocols for many of the common experimental approaches in plant developmental bi- ogy. All chapters are written in the same format as that used in the Methods in Molecular TM Biology series. Each chapter opens with a description of the basic theory behind the method being described.

The last few years have seen the rapid development of new methodology in the field of molecular biology. New techniques have been regularly introduced and the sensitivity of older techniques greatly improved upon. Developments in the field of genetic engineering in particular have contributed a wide range of new techniques. The purpose of this book therefore is to introduce the reader to a selection of the more advanced analytical and preparative techniques which the editors consider to be frequently used by research workers in the field of molecular biology. In choosing techniques for this book we have obviously had to be selective, and for the sake of brevity a knowledge of certain basic biochemical techniques and terminology has been assumed. However, since many areas of molecular biology are developing at a formidable rate and constantly generating new terminology, a glossary of terms has been included. The techniques chosen for this book are essentially based on those used in a series of workshops on 'techniques in molecular biology' that have been held at The Hatfield Polytechnic in recent years. In choosing these chapters we have taken into account many useful suggestions and observations made by participants at these workshops. Each chapter aims to describe both the theory and relevant practical details for a given technique, and to identify both the potential and limitations of the technique. Each chapter is written by authors who regularly use the technique in their own laboratories.

The past several decades have witnessed an impressive array of conceptual and techno logical advances in the biomedical sciences. Much of the progress in this area has developed directly as a result of new morphology-based methods that have permitted the assessment of chemical, enzymatic, immunological, and molecular parameters at the cellular and tissue levels. Additional novel approaches including laser capture microdissection have also emerged for the acquisition of homogeneous cell popula tions for molecular analyses. These methodologies have literally reshaped the approaches to fundamental biological questions and have also had a major impact in the area of diagnostic pathology. Much of the groundwork for the development of morphological methods was estab th lished in the early part of the 19 century by Francois-Vincent Raspail, generally acknowledged as the founder of the science of histochemistry. The earliest work in the field was primarily in the hands of botanists and many of the approaches to the under standing of the chemical composition of cells and tissues involved techniques such as microincineration, which destroyed structural integrity. The development of aniline th dyes in the early 20 century served as a major impetus to studies of the structural rather than chemical composition of tissue. Later in the century, however, the focus returned to the identification of chemical constituents in the context of intact cell and tissue structure.

Developmental biology is a newly-developing subject that is attracting much interest because of exciting findings being made using a combination of classical embryo manipulation with more modern techniques. This book brings together for the first time, and in comprehensive, easy-to-follow protocols, practical instructions for all of the main techniques, from traditional embryology to cellular and molecular methods. It includes complete reprints of all the stage tables in common use for the main laboratory species. It will become an essential addition to laboratory benches of those using any technique as applied to embryos, cells, or tissues.