This book presents a completely novel approach to the understanding of ageing, which many believe is an unsolved problem in biology. It explains why ageing exists in animals, and reviews our understanding of it at the biological level. This includes a discussion of the origins and evolution of ageing. The book is not a review of research on ageing, but instead draws on material from a wide range of disciplines, including the very extensive biomedical information about age-related diseases in humans. Understanding Ageing argues that much research needs to be done on the cellular and molecular aspects of ageing, if the origins of these diseases are to be understood, and their prevention made possible. This thought-provoking book will appeal to all students and researchers who are interested in ageing, whether they are working in the clinical or basic research sphere.

Why do we age? Is aging inevitable? Will advances in medical knowledge allow us to extend the human lifespan beyond its present limits? Because growing old has long been the one irreducible reality of human existence, these intriguing questions arise more often in the context of science fiction than science fact. But recent discoveries in the fields of cell biology and molecular genetics are seriously challenging the assumption that human lifespans are beyond our control. With such discoveries in mind, noted cell biologist William R. Clark clearly and skillfully describes how senescence begins at the level of individual cells and how cellular replication may be bound up with aging of the entire organism. He explores the evolutionary origin and function of aging, the cellular connections between aging and cancer, the parallels between cellular senescence and Alzheimer's disease, and the insights gained through studying human genetic disorders--such as Werner's syndrome--that mimic the symptoms of aging. Clark also explains how reduction in caloric intake may actually help increase lifespan, and how the destructive effects of oxidative elements in the body may be limited by the consumption of antioxidants found in fruits and vegetables. In a final chapter, Clark considers the social and economic aspects of living longer, the implications of gene therapy on senescence, and what we might learn about aging from experiments in cloning. This is a highly readable, provocative account of some of the most far-reaching and controversial questions we are likely to ask in the next century.

The rapid development of molecular biology and genetics has led to renewed interest in embryology, comparative embryology, and studies of the relations between ontogeny and phylogeny. In fact, genes have been identified which are involved in the formation of shapes and structures, and it is becoming apparent that their primary morphological expressions are conspicuously similar in different species. The primarily identical shapes do not become diversified until advanced individualization of embryos, and it is here that it is possible to employ the knowledge of comparative embryology, the branch of science engaged in the study of the development and differentiation of tridimensional structures in different animal groups. However, comparative embryology has been neglected during the past decades, as its development has appeared to have been completed. In our opinion, the decreased interest in comparative embryology has been caused by the fact that often the time factor was not or could not be respected. In fact, in the case of embryos of wild animals even their ontogenetic age and sometimes the duration of intrauterine development are unknown.

Sex differences are observed in various physiological, behavioral, and psychic functions, including reproductive behavior, aggres sion, emotions, and cognition. Such differences are expressed even in early childhood with preferences to definite activities. It has been generally accepted that differences between genders are formed under the influence of biological as well as environmental factors. The existence of sex differences in functions of the central nervous system has suggested that there are also morphological sex differences. In recent years several reports on sexual dimorphism in the brain of vertebrates have been published. However, the mecha nisms of sexual differentiation of the central nervous system remain unclear in most cases. It is often difficult to correlate morphological sex differences to differences in definite function or behavior. We set out to explore the sexual dimorphism of the limbic system and especially the bed nucleus of the stria terminalis and the amygdala, which are considered generally to be occupied with the control of reproductive behavior and autonomic and compli cated psychic functions. Several reports on sexual dimorphism of these structures have been published. Some of them have been directed to the total neuronal number and the volume of the nuclei, while others have concentrated on definite subpopula tions of neurons. In many cases the mechanisms of sexual differ entiation were tested, but sometimes they could not be estab lished."

Development of the shapes of living organisms and their parts is a field of science in which there are no generally accepted theoretical principles. What form these principles are likely to take, when they emerge, is a subject in which there is a wide gulf of disagreement between physical scientists and experimental biologists. This book contains both an extensive philosophical commentary on this dichotomy in views and an exposition of the type of theory most favoured by physical scientists. In this theory living form is a manifestation of the dynamics of chemical change and physical transport or other physics of spatial communication. The reaction-diffusion theory, as initiated by Turing in 1952 and since elaborated by Prigogine and by Gierer and Meinhardt among others, is discussed in detail at a level that requires a good knowledge of a first course in calculus, but no more than that.

Drawing on state-of-the-art cellular and molecular techniques as well as new and sophisticated imaging and information technologies, this comprehensive, three-volume collection of cutting-edge protocols provides readily reproducible methods for studying and analyzing the events of embryonic development. volume 1 (ISBN: 089603-574-3) contains techniques for establishing and characterizing several widely used experimental model systems, for the study of developmental patterns and morphogenesis, and for the examination of embryo structure and function. There are also step-by-step methods for the analaysis of cell lineage, the production and use of chimeras, and the experimental and molecular manipulation of embryos, including the application of viral vectors. volume 2 (ISBN: 0-89603-575-1) describes state-of-the-art methods for the study of organogenesis, the analysis of abnormal development and teratology, the screening and mapping of novel genes and mutations, and the application of transgenesis, including the production of transgenic animals and gene knockouts. No less innovative, volume 3 (ISBN: 0-89603-576-X) introduces powerful techniques for the manipulation of developmental gene expression and function, the analysis of gene expression, the characterization of tissue morphogenesis and development, the in vitro study of differentiation and development, and the genetic analysis of developmental models of diseases. Highly practical and richly annotated, the three volumes of Developmental Biology Protocols describe multiple experimental systems and details techniques adopted from the broadest array of biomedical disciplines.

This timely account provides a comprehensive contemporary analysis of morphogenetic processes in vertebrate and invertebrate embryos. Morphogenesis, the generation of tissue organization in embryos, is an increasingly important subject. This is partly because the techniques for investigating many morphogenetic mechanisms have only recently become available and partly because studying the genomic basis of embryogenesis requires an understanding of the developmental phenotype. Following an introduction covering case studies and historical and technical approaches, the book reviews the mechanistic roles of extracellular matrices, cell membranes and the cytoskeleton in morphogenesis. A detailed discussion of how mesenchymal and epithelial cells cooperate to build a wide range of tissues is also included. The book concludes with a dynamical analysis of the subject. With its extensive literature review (more than 500 titles), this book will interest developmental biologists and will also serve as an advanced textbook for postgraduate and final year students.

From deep ocean trenches and the geographical poles to outer space, organisms can be found living in remarkably extreme conditions. This book provides a captivating account of these systems and their extraordinary inhabitants, 'extremophiles'. A diverse, multidisciplinary group of experts discuss responses and adaptations to change; biodiversity, bioenergetic processes, and biotic and abiotic interactions; polar environments; and life and habitability, including searching for biosignatures in the extraterrestrial environment. The editors emphasize that understanding these systems is important for increasing our knowledge and utilizing their potential, but this remains an understudied area. Given the threat to these environments and their biota caused by climate change and human impact, this timely book also addresses the urgency to document these systems. It will help graduate students and researchers in conservation, marine biology, evolutionary biology, environmental change and astrobiology better understand how life exists in these environments and their susceptibility or resilience to change.

The technique of allometry investigates the effects of size on such variables as food intake, energy requirements, growth rates and age at first reproduction. This book, now available in paperback, brings together much of what is known about the consequences of size and provides a new and mathematically rigorous framework within which many quantitative predictions are made and tested using published and unpublished data. New explanations are proposed for many previously unexplained phenomena such as why in some species females are thousands of times heavier than males, whereas in no species are males more than about eight times heavier than females. The models presented afford a new synthesis of the effects of size and open up more pathways for further theoretical investigation and experimental testing. Care has been taken to give verbal presentations of all the mathematical conclusions to ensure that the text is widely intelligible.

This is the first book that attempts to bring together what is known about the fundamental mechanisms that underlie the development of the cortex in mammals. Ranging from the emergence of the forebrain from the neural plate to the functioning adult form, the authors draw on evidence from several species to provide a detailed description of processes at each stage. Where appropriate, evidence is extrapolated from non-mammalian species to generate hypotheses about mammalian development. In contrast to other texts of developmental biology, Mechanisms of Cortical Development integrates information on regulatory processes at the levels of molecules, cells and metworks. The authors draw together an extensive literature on cellular development and structural morphology, biochemical and genetic events and hypotheses that have been subject to mathematical modelling. Important metholdogies, such as transgenics and formal modelling, are explained for the non-specialist. Major future challenges are clearly identified. This is a unique contribution to the literature, combining the fundamentals of experimental developmental neurobiology with accessible neural modelling. It will be essential reading for neuroscientists in general as well as those with a particular interest in development.

The past decade has seen a dramatic increase in our understanding of early animal development. The revised edition of this excellent book describes the results of this revolution and explains in detail how the body plan of an embryo emerges from a newly fertilized egg. The book starts with a critical discussion of embryological concepts, and with simple mathematics describes cell states, morphogen gradients, and threshold responses. The experimental evidence of the mechanisms of regional specification in vertebrates, insects, and selected invertebrates, namely frogs (Xenopus), mice, chicks, fruitflies (Drosophila), mollusks, ringed worms, sea squirts, and nematode worms (Caenorhabditis), is then discussed. The progress with Drosophila has been particularly impressive, and there is an entire chapter devoted to it that provides a clear guide to the subject and includes a new table of developmentally important genes. Throughout, the emphasis is on conceptual clarity and unity, and the book brings together mathematical models, embryological experiments, and molecular biology in a single comprehensible and coherent account.

Morphogeny of the nasal skull was investigated in 92 embryos of 13 species of Cetacea. Compared to the original nasal capsule of land mammals, the nasal structures of Cetacea show many weighty transformations. As a result, the nostrils are translocated from the tip of the snout to the vertex of the head. Several structures of the embryonic nasal skull remain preserved even in adult cetaceans. The translocation of the nostrils to the highest point of the surfacing body is among the most perfect adaptations of cetaceans to the aquatic life habits. The morphogeny of the nasal skull suggests that all cetaceans are of common origin and form a single monophyletic order. The hitherto usual division of this order into two suborders, Mysticeti and Odontoceti, appears to be unsubstantiated. Rather, at least three closely related superfamilies should be distinguished within the order Cetacea, viz., Balaenopteroidea, Physeteroidea, and Delphinoidea. The results are in a

Plants are an advantageous group for the consideration of the development of biological form. Plants share most aspects of cell biology with other organisms, yet their embryonic development continues throughout their life, their cells do not move relative to each other and their structure is relatively simple. The chapters in this book are centred around the structure of tissues and its purpose is to try and predict what should be looked for at a molecular level so as to account for observable forms. Each chapter deals with a defined problem such as the role of hormones as correlative agents, tissue polarization, apical meristems and cell lineages. The final chapter develops an alternative approach to the problem of the specification of biological form, that of 'epigenetic selection'. The chapters are centred around the structure of tissues, an intermediate and neglected level between overt morphology and biochemistry, and will be of great interest to all those engaged in attempting to understand the principles behind plant development.

Drawing on state-of-the-art cellular and molecular techniques as well as new and sophisticated imaging and information technologies, this comprehensive, three-volume collection of cutting-edge protocols provides readily reproducible methods for studying and analyzing the events of embryonic development. Volume 1 (ISBN: 089603-574-3) contains techniques for establishing and characterizing several widely used experimental model systems, for the study of developmental patterns and morphogenesis, and for the examination of embryo structure and function. There are also step-by-step methods for the analaysis of cell lineage, the production and use of chimeras, and the experimental and molecular manipulation of embryos, including the application of viral vectors. Volume 2 (ISBN: 0-89603-575-1) describes state-of-the-art methods for the study of organogenesis, the analysis of abnormal development and teratology, the screening and mapping of novel genes and mutations, and the application of transgenesis, including the production of transgenic animals and gene knockouts. No less innovative, volume 3 (ISBN: 0-89603-576-X) introduces powerful techniques for the manipulation of developmental gene expression and function, the analysis of gene expression, the characterization of tissue morphogenesis and development, the in vitro study of differentiation and development, and the genetic analysis of developmental models of diseases. Highly practical and richly annotated, the three volumes of Developmental Biology Protocols describe multiple experimental systems and details techniques adopted from the broadest array of biomedical disciplines.

This work is a brief review of the pre- and postnatal development in the North American opossum (Didelphis virginiana) presented in two volumes. Volume I summarizes gametes and fertilization, blastocyst formation and early organogenesis, fetal membranes and placentation, parturition and migration to the pouch, general postnatal growth and development, and histogenesis/organogenesis of the integument, musculoskeletal system, cardiovascular system, blood and blood forming organs, lymphatic organs, nervous system, eye, and ear. Volume II summarizes the histogenesis/organogenesis of the respiratory, digestive, urinary, male and female reproductive and classical endocrine systems.

Due to their pronounced intraspecific variability and to difficulties in defining their evolutionary trends in mammalian phylogenies, peripheral blood vessels have been neglected in comparative studies. Supported by the Sonderforschungsbereich 89 (Car- diology) of the Deutsche Forschungsgemeinschaft, we have reconstructed the ontoge- of the blood vessels of the tree shrew, Tupaia belangeri, on the netic morphogenesis basis of a series of developmental stages. The arteries of the lower extremity are described and discussed here. Besides describing the morphogenesis of the arteries in Tupaia, it is the aim of this study to explain the variability of the arteries of the pelvic extremity among mammals, and especially among primates including man, on the basis of a common developmen- tal pattern. This can be shown in the following example. In the popliteal region of most adult mammals the arteria poplitea profunda is situated under the musculus popliteus. In the adult Tupaia, as well as in primates, this artery is missing but, superficial to the musculus popliteus, an arteria poplitea super- ficialis exists. It seems difficult to explain such a case of "discontinuous evolution," because it is hard to imagine the position of the artery should have shifted through the muscle. The present investigation and the literature show that early in the embryonic development of a primate, man, and of Tupaia, both the arteria poplitea profunda and the arteria poplitea superficialis are present.

This work is a brief review of the pre- and postnatal development in the North American opossum (Didelphis virginiana) presented in two volumes. Volume I summarizes gametes and fertilization, blastocyst formationan and early organogenesis, fetal membranes and placentation, parturition and migration to the pouch, general postnatal growth and development, and histogenesis/organogenesis of the integument, musculoskeletal system, cardiovascular system, blood and blood forming organs, lymphatic organs, nervous system, eye, and ear. Volume II summarizes the histogenesis/organogenesis of the respiratory, digestive, urinary, male and female reproductive and classical endocrine systems.

Drawing on state-of-the-art cellular and molecular techniques as well as new and sophisticated imaging and information technologies, this comprehensive, three-volume collection of cutting-edge protocols provides readily reproducible methods for studying and analyzing the events of embryonic development. volume 1 (ISBN: 089603-574-3) contains techniques for establishing and characterizing several widely used experimental model systems, for the study of developmental patterns and morphogenesis, and for the examination of embryo structure and function. There are also step-by-step methods for the analaysis of cell lineage, the production and use of chimeras, and the experimental and molecular manipulation of embryos, including the application of viral vectors. volume 2 (ISBN: 0-89603-575-1) describes state-of-the-art methods for the study of organogenesis, the analysis of abnormal development and teratology, the screening and mapping of novel genes and mutations, and the application of transgenesis, including the production of transgenic animals and gene knockouts. No less innovative, volume 3 (ISBN: 0-89603-576-X) introduces powerful techniques for the manipulation of developmental gene expression and function, the analysis of gene expression, the characterization of tissue morphogenesis and development, the in vitro study of differentiation and development, and the genetic analysis of developmental models of diseases. Highly practical and richly annotated, the three volumes of Developmental Biology Protocols describe multiple experimental systems and details techniques adopted from the broadest array of biomedical disciplines.

Advances in our understanding of biological mechanisms have frequently been associated with the development of techniques. In situ hybridisation is a classic case of just such an advance. The technique effectively combines histochemistry with molecular biology and enables the rapid analysis of the distribution of RNA, or DNA, in the tissues. The information gained from this has caused something of a revolution in our understanding of developmental biology, since a fundamental aspect of development is the spatial and temporal expression of genes. In addition the technique has found application in the field of medicine, providing insights into the functioning of healthy tissues and the diagnosis and study of diseases. This book brings together contributions from leaders in the application of in situ hybridisation and guides the would-be exponent through the various options and variations of the technique.

This manual describes the methodology and applications of microinjection, a powerful technique for transposing material into living cells through needle injection. Information is presented on the techniques principles, the required equipment, preparation of receiving cells and injected material, and the analysis of results. Detailed protocols for a wide range of applications in different cellular systems are included. A large part of the book is also dedicated to the Xenopus laevis oocyte system.

During animal development the descendants of a single cell form many different tissues and organs in appropriate positions within an embryo. To do this they must recognise their position, and our knowledge of how this is done is examined in this book. It starts by considering how much spatial pattern is already laid down when the egg forms inside the mother, and ends just before the formation of visible organs. Within these limits it considers evidence obtained by a variety of techniques, both experimental and biochemical, and from the embryos of many different animal groups. This breadth of coverage and the amount of detail afforded, particularly to the experimental studies, distinguish it from competing works and will make it an interesting review. Moreover, in the final chapter the author analyzes this evidence in ways which will be new to most readers, and which call into question current ideas about spatial determination.

Morphogenesis, the set of processes that generate shape and form in the embryo, remains a central area in developmental biology. This book, first published in 1990, provides an overview of the events and mechanisms of morphogenesis, reviewing the major molecular and cellular mechanisms underlying morphogenetic change and describing how these processes are integrated during normal development. Most of the major embryological systems, both vertebrate and invertebrate, are discussed, with extensive coverage of the molecular mechanisms of morphogenesis involving the extracellular matrix, the membrane and the cytoskeleton. The major focus of the book, however, is on those properties of mesenchymal and epithelial cells responsible for organogenesis, while the extensive reference cover of the historical and contemporary literature (more than 500 titles) provides a useful research tool in this very wide field. This book is aimed at both scholars in the field of embryology, and postgraduate and final-year students in development and anatomy.

The phenomenon of sexual reproduction in eukaryotes poses a special problem: with each union of gametes, how does the species avoid a doubling of chromosome numbers? The solution that eukaryotes invented, early in their evolutionary history, is a unique form of nuclear division, meiosis. Meiosis serves to reduce chromosome numbers by a factor of two in the gamete or gamete-forming cells, with the result that each gamete (or gamete precursor) has a single copy of each chromosome, the haploid state; the union of gametes then restores the pre-gametic or diploid chromosome number. In this book, Bernard John presents a complete review of meiosis, describing its mechanics, position in the life cycle in different species, genetics and, finally, its significance in eukaryotic evolution. For students and researchers interested in eukaryotic cellular biology and genetics, this book may prove useful. Upper division students and research workers in genetics, cytology, and cell biology will also be able to refer to this book.

Patterns in Plant Development offers an introduction to the development of the whole plant. It is essentially a factual book that describes the complex phenomena of development in vascular plants. The point of view is structural, and emphasis is placed on the experimental approach to development. The book deals with lower vascular plants (e.g. ferns) as well as seed plants, so that the treatment of the plant, beginning with the embryo and continuing through the phase of secondary growth (the vascular cambium) is presented. The book is written so that anyone who has completed a basic first-year university course in biology or botany will be able to use it without difficulty. Sufficient background information is provided so that the reader is not required to have an extensive technical background.

Patterns in Plant Development offers an introduction to the development of the whole plant. It is essentially a factual book that describes the complex phenomena of development in vascular plants. The point of view is structural, and emphasis is placed on the experimental approach to development. The book deals with lower vascular plants (e.g. ferns) as well as seed plants, so that the treatment of the plant, beginning with the embryo and continuing through the phase of secondary growth (the vascular cambium) is presented. The book is written so that anyone who has completed a basic first-year university course in biology or botany will be able to use it without difficulty. Sufficient background information is provided so that the reader is not required to have an extensive technical background.