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Mechanisms of Morphogenesis, Third Edition offers a bottom-up discussion of mechanisms of cell and tissue morphogenesis in a diverse array of organisms, including prokaryotes, animals, plants and fungi. Across foundational, applied and methods-based chapters, this book examines molecular nano-machines cooperation, generate cell shape, direct cell migration, and shape, form and rates of growth of various tissues in the body. Each topic is illustrated with experimental data from real systems, with particular reference to gaps in current knowledge and likely future developments, along with strategies to apply basic morphogenesis science across ever evolving applications. Newly added chapters feature case-study-driven discussions of morphogenesis in natural embryos and organoids, and illustrate how pathological morphogenesis can generate variants of body form. This edition has also been updated with analysis of large-scale and scale-invariant mechanisms, for example, morphogenesis by differential growth in mechanically connected tissues. Includes over 200 full color figures and charts Offers an integrated view of theoretical developmental biology and computer modeling with laboratory-based discoveries Includes applied, case-study-driven discussion of experimental techniques Is organized around principles and mechanisms, using them to integrate discoveries from a range of organisms and systems across new applications Covers recent developments in morphogenesis research, including morphogenesis in organoids, other engineered tissues, and an analysis of large-scale and scale-invariant mechanisms

Resident Stem Cells and Regenerative Therapy: Sources and Clinical Applications, Second Edition presents the main findings to date and the important factors to be considered when contemplating resident stem cells in regenerative therapies. Chapters on cardiac, brain, neural, liver, kidney, skeletal muscle, bone, pancreatic, skin and lung resident stem cells will assist in defining the level of success that has been achieved and the direction for the road ahead. With contributions from leading laboratories, open questions related to resident stem cells and regenerative therapies will also be presented for debate. In the last several decades, stem cells have greatly impacted the scientific and lay communities, providing huge advances in the treatment of devastating human diseases, including myocardial infarction, diabetes, muscular dystrophy, cystic fibrosis, cirrhosis, and osteoporosis. Alongside debates of induced pluripotent stem cells and embryonic stem cells has been the discovery of adult stem cells in many different tissues. While these organ resident or progenitor stem cells offer prospects to contribute to tissue regeneration, they also present challenges because of the complexity of organ structures. Highlights basic research in tissue specific stem cells, experiments with animal models, and clinical trials that are transforming the field of regeneration Provides a clear understanding of endogenous stem cells, their role in current regenerative therapies, and prospects for future research Reports on the main-stream clinical approaches and in vivo experiments published in primary literature to help categorizes the advances in various aspects of regenerative therapy and illustrate opportunities for clinical applications

In the vasculature, the extracellular matrix (ECM) is involved in the regulation of angiogenesis, vascular mechanosensing, and blood vessel stability. This book aims to provide the reader with an overview of the various roles of the ECM during angiogenesis and covers its important role for the maintenance of vascular integrity, capillary and arterial morphogenesis, as well as lymphangiogenesis. Furthermore, aspects of regulation of endothelial cell and pericyte functions by the ECM under physiological and pathological conditions are discussed. In addition, the reader will learn more about different approaches to exploit ECM molecules for designing therapeutic approaches or as biomarkers to improve therapeutic decisions. Comprehensive and cutting-edge, Matrix Pathobiology and Angiogenesis is a valuable resource for experienced researchers and early career scientist alike, who are interested in in learning more about this exciting and developing field. The series Biology of Extracellular Matrix is published in collaboration with the American Society for Matrix Biology and the International Society for Matrix Biology.

Encyclopedia of Respiratory Medicine, Second Edition, Six Volume Set explores the key processes of lung diseases and their diagnosis and management. The book dissects the molecular and cellular biology, physiology and immunology that underpin normal lung function, along with the aberrations that occur in respiratory diseases, from common disorders such as asthma and COPD to rarer lung diseases such as cystic fibrosis, interstitial lung diseases and pulmonary hypertension. Written in at a time when the globe is in the grip of respiratory pandemic, lung disease has never been so prominent in the public and political conscious. This new edition will provide new researchers in respiratory medicine with a solid foundation in unfamiliar topics and will update more experienced researchers seeking to step outside their core areas of research to put their work into a broader context. Presents a ‘one-stop'resource covering the entire scope of modern respiratory medicine Brings together a truly global collaboration of some of the most authoritative voices in respiratory medicine Provides chapters that are concise and accessible, with an authoritative introduction for non-specialists, as well as up-to-date, foundational content for those familiar with the field Includes multimedia-rich content, including hundreds of clear and helpful illustrations that can be used as teaching aids

Much research has focused on the basic cellular and molecular biological aspects of stem cells. Much of this research has been fueled by their potential for use in regenerative medicine applications, which has in turn spurred growing numbers of translational and clinical studies. However, more work is needed if the potential is to be realized for improvement of the lives and well-being of patients with numerous diseases and conditions.This book series'Cell Biology and Translational Medicine (CBTMED)'as part of SpringerNature's longstanding and very successful Advances in Experimental Medicine and Biology book series, has the goal to accelerate advances by timely information exchange. Emerging areas of regenerative medicine and translational aspects of stem cells are covered in each volume. Outstanding researchers are recruited to highlight developments and remaining challenges in both the basic research and clinical arenas. This current book is the tenth volume of a continuing series.

This is a comprehensive guide to single-stranded RNA phages (family Leviviridae), first discovered in 1961. These phages played a unique role in early studies of molecular biology, the genetic code, translation, replication, suppression of mutations. Special attention is devoted to modern applications of the RNA phages and their products in nanotechnology, vaccinology, gene discovery, evolutionary and environmental studies. Included is an overview of the generation of novel vaccines, gene therapy vectors, drug delivery, and diagnostic tools exploring the role of RNA phage-derived products in the revolutionary progress of the protein tethering and bioimaging protocols.Key Features Presents the first full guide to single-stranded RNA phages Reviews the history of molecular biology summarizing the role RNA phages in the development of the life sciences Demonstrates how RNA phage-derived products have resulted in nanotechnological applications Presents an up-to-date account of the role played by RNA phages in evolutionary and environmental studies

This book presents a comprehensive discussion on the heterogeneity existing between different types of stem cells within the same tissue. As the functions of these stem cells vary, this is very important for the application of stem cells in cell therapy. This book describes the many recent developments that have revealed completely different roles of distinct stem cells within the same organ.Stem Cells Heterogeneity in Different Organs provides a timely update on the current information on stem cells heterogeneity in various tissues. It also provides a solid foundation of the history of stem cells from specific tissues and the current applications of this knowledge in regenerative medicine. Taken with its companion volumes, Stem Cells Heterogeneity: Novel Concepts and Stem Cells Heterogeneity in Cancer, this book is essential reading for advanced cell biology students as well as researchers and clinicians working with stem cells.

The present book is an attempt to describe the most recent developments in the area of pericyte biology which is one of the emergent hot topics in the field of molecular and cellular biology today. Here, we present a selected collection of thirteen detailed chapters on what we know so far about pericytes in distinct organs in physiological and pathological conditions. Further, it provides an update on the most novel functions attributed to these cells and will introduce a newer generation of researchers and scientists to the importance of these cells, ranging from their discovery in different organs through current state-of-the-science. It will be invaluable for both advanced cell biology students as well as researchers in cell biology, stem cells and vascular research. This volume explores pericytes'physiologic roles in different tissues, ranging from the pancreas, lungs and liver through skeletal muscle, gut, retina and more. Together with its companion volumes Pericyte Biology in Disease and Pericyte Biology – Novel Concepts, Pericyte Biology in Different Organs presents a comprehensive update on the latest information and most novel functions attributed to pericytes. To those researchers newer to this area, it will be useful to have the background information on these cells'unique history. It will be invaluable for both advanced cell biology students as well as researchers in cell biology, stem cells and researchers or clinicians involved with specific organs.

This book covers the identification and role of endogenous lung stem cells in health and disease, particularly the most recent advances. In addition, it discusses the rapidly growing field of stem cells and cell therapy as it relates to lung biology and disease as well as ex vivo lung bioengineering. Such approaches may provide novel therapeutic approaches for lung diseases. Human pluripotent stem cell differentiation to model the pulmonary epithelium and vasculature is also discussed.World-recognized scientists who specialize in studying both the lung epithelium and pulmonary vasculature contribute the chapters. Topics covered include: stem cell niches in the lung, the role of progenitor cells in fibrosis and asthma, iPSC in modeling lung disease, vascular repair by endothelial progenitor cells and circulating fibrocytes in pulmonary vascular remodeling. This volume of the Stem Cell Biology and Regenerative Medicine series is essential reading for researchers and clinicians interested in stem cells, lung biology and regenerative medicine. It is also an invaluable resource for advanced students studying cell biology, regenerative medicine and lung physiology.

Adult Stem Cells, second edition, takes a critical look at issues concerning the developmental or differentiation potential for a variety of tissue types and for specific adult stem cell types. Since the first edition appeared a decade ago, our understanding of adult stem cells, and more specifically tissue-specific adult stem cells, has advanced tremendously. And an increased interest in regenerative medicine and potential stem cell applications has driven a quest for better understanding of stem cell biology. In turn, this has spawned much activity on generation and utilization of more and better reagents to identify and isolate stem cells and stem cell-like subpopulations, and on assays elucidating their developmental or differentiation potential and functional integration with host tissues and organs. In this fully updated new edition, chapters cover topics ranging from signaling pathways maintaining stemness in hematopoietic cells to regeneration after injury and endocrine mechanisms underlying the stem cell theory of aging. Other chapters cover stem cells by organ or system including pituitary, cardiac, epithelial, teeth, lung, ovary, prostate, liver, and many more. Importantly, the authors of the chapters have not only summarized their successes, but have also summarized some of the difficulties that each particular field is still facing with respect to maximizing the utility of stem cells in clinical settings. Collectively, they impart both the excitement and challenges facing stem cell utilization for repair and regeneration making this book essential reading for those involved in stem cell research as well as those involved in clinical assays.

This first of two volumes provides a general overview of the genetics, structure, mechanism and regulation of the Ras superfamily proteins and describes in detail the signaling pathways and processes regulated by specific members of this family. The focus of this first volume is on the Rho and Ras subfamily of small G proteins.Renowned scientists provide insights into the biochemistry of the classical and non-classical small G-protein family members, their spatio-temporal regulation, their effectors and their roles in health and disease. Together with Volume 2, this book provides a comprehensive and state-of-the-art work on small G-proteins (GTPases). It is intended for graduates and professors in biochemistry and cell biology already working on small G-proteins (small GTPases), but also offers an extremely valuable resource for those readers who are new to the field.

The heart is invested with a complex, intertwining network of blood and lymphatic vessels which, respectively, provide the cardiac tissue with oxygen and nutrients and eliminate excess fluid from the interstitium. The coronary blood vessels have been the focus of much investigation in the past few decades. On the other hand, the literature regarding the cardiac lymphatic vessels remains sparse, despite their important role in maintaining normal heart function. With this in mind, a better understanding of the cardiac lymphatic network and its ability to regulate fluid homeostasis within the heart could give us insight into developing therapies for the alleviation of several cardiac pathological conditions.

In the last 3 decades, stem cells have greatly impacted the scientific and lay communities, providing huge advances in the treatment of devastating human diseases, including myocardial infarction, diabetes, muscular dystrophy, cystic fibrosis, cirrhosis, and osteoporosis. Alongside debates of induced pluripotent stem cells and embryonic stem cells has been the discovery of adult stem cells in many different tissues. While these organ resident or progenitor stem cells offer prospects to contribute to tissue regeneration, they also present challenges because of the complexity of organ structures. This book will present the main findings to date and the important factors to be considered when considering resident stem cells in regenerative therapies. Chapters on cardiac, brain, neural, liver, kidney, skeletal muscle, bone, pancreatic, skin, and lung resident stem cells will assist in defining the level of success that has been achieved and the direction for the road ahead. With contributions from leading laboratories, open questions related to resident stem cells and regenerative therapies will also be presented for debate. Highlights basic research in tissue specific stem cells, experiments with animal models and clinical trials that are transforming the field of regeneration Provides a clear understanding of endogenous stem cells, their role in current regenerative therapies, and prospects for future research Reports on the main-stream clinical approaches and in vivo experiments published in primary literature to help categorizes the advances in various aspects of regenerative therapy and illustrate opportunities for clinical applications

Morphogenesis is the set of processes that generate shape and form in the embryo--an important area within developmental biology. An exciting and up-to-the-minute account of the very latest research into the factors that create biological form, Mechanisms of Morphogenesis, second edition is a text reference on the mechanisms of cell and tissue morphogenesis in a diverse array of organisms, including prokaryotes, animals, plants and fungi. By combining hard data with computer modeling, Mechanisms of Morphogenesis, second edition equips readers with a much broader understanding of the scope of modern research than is otherwise available. The book focuses on the ways in which the genetic program is translated to generate cell shape, to direct cell migration, and to produce the shape, form and rates of growth of the various tissues. Each topic is illustrated with experimental data from real systems, with particular reference to gaps in current knowledge and pointers to future Includes over 200 four-color figures Offers an integrated view of theoretical developmental biology and computer modelling with laboratory-based discoveries Covers experimental techniques as a guide to the reader Organized around principles and mechanisms, using them to integrate discoveries from a range of organisms and systems

International Review of Cell and Molecular Biology presents current advances and comprehensive reviews in cell biology--both plant and animal. Articles address structure and control of gene expression, nucleocytoplasmic interactions, control of cell development and differentiation, and cell transformation and growth. Authored by some of the foremost scientists in the field Provides up-to-date information and directions for future research Valuable reference material for advanced undergraduates, graduate students and professional scientists

In recent years remarkable progress has been accomplished with respect to our knowledge about bacterial protein toxins. This refers especially to structural aspects of protein toxins but also holds true for genetics, molecular biology and biochemical mechanisms underlying the action of toxins. This volume covers the very current and exciting aspects of up-to-date bacterial toxicology and comprehensively reviews the most important bacterial protein toxins such as the intracellular acting toxins which exhibit enzyme activity, as well as those toxins that interact with cell plasma membranes by damaging the membranes (pore formation) or stimulating cell receptors (superantigens). This is the most current reference work on these important bacterial protein toxins, which are presented from the point of view of different disciplines such as pharmacology, microbiology, cell biology and protein chemistry.

Cells in the developing embryo depend on signals from the extracellular environment to help guide their differentiation. An important mediator in this process is the extracellular matrix – secreted macromolecules that interact to form large protein networks outside the cell. During development, the extracellular matrix serves to separate adjacent cell groups, participates in establishing morphogenic gradients, and, through its ability to interact directly will cell-surface receptors, provides developmental clocks and positional information. This volume discusses how the extracellular matrix influences fundamental developmental processes and how model systems can be used to elucidate ECM function. The topics addressed range from how ECM influences early development as well as repair processes in the adult that recapitulate developmental pathways.

Published since 1959, Advances in Applied Microbiology continues to be one of the most widely read and authoritative review sources in microbiology. The series contains comprehensive reviews of the most current research in applied microbiology. Recent areas covered include bacterial diversity in the human gut, protozoan grazing of freshwater biofilms, metals in yeast fermentation processes and the interpretation of host-pathogen dialogue through microarrays. Eclectic volumes are supplemented by thematic volumes on various topics, including Archaea and sick building syndrome. Impact factor for 2010: 3.913. Contributions from leading authorities Informs and updates on all the latest developments in the field

International Review of Cell and Molecular Biology presents current advances and comprehensive reviews in cell biology--both plant and animal. Articles address structure and control of gene expression, nucleocytoplasmic interactions, control of cell development and differentiation, and cell transformation and growth. Impact factor for 2009: 6.088. Authored by some of the foremost scientists in the field Provides up-to-date information and directions for future research Valuable reference material for advanced undergraduates, graduate students and professional scientists

Extensively revised and updated, the new edition of the highly regarded Handbook of Proteolytic Enzymes is an essential reference for biochemists, biotechnologists and molecular biologists. Edited by world-renowned experts in the field, this comprehensive work provides detailed information on all known proteolytic enzymes to date. This two-volume set unveils new developments on proteolytic enzymes which are being investigatedin pharmaceutical research for such diseases as HIV, Hepatitis C, and the common cold. Volume I covers aspartic and metallo petidases while Volume II examines peptidases of cysteine, serine, threonine and unknown catalytic type. A CD-ROM accompanies the book containing fully searchable text, specialised scissile bond searches, 3-D color structures and much more. The only comprehensive book on proteolytic enzymes Includes 671 chapters, each written by experts in their field, on proteolytic enzymes from all groups of living organisms and the viruses, including those that are currently major targets of pharmaceutical research Accompanying CD-ROM provides fully searchable text, 2D structures of peptidases in color and links directly to PubMed and MEROPS databases Each chapter describes in detail the enzyme name, its history, activity and specificity, structural chemistry, preparation, biological aspects and distinguishing features Over 1000 peptidases included

Knowledge of the extracellular matrix (ECM) is essential to understand cellular differentiation, tissue development, and tissue remodeling.This volume of the series “Biology of Extracellular Matrix” provides a timely overview of the structure, regulation, and function of the major macromolecules that make up the extracellular matrix. It covers topics such as collagen types and assembly of collagen-containing suprastructures, basement membrane, fibronectin and other cell-adhesive glycoproteins, proteoglycans, microfibrils, elastin, fibulins and matricellular proteins, such as thrombospondin. It also explores the concept that ECM components together with their cell surface receptors can be viewed as intricate nano-devices that allow cells to physically organize their 3-D-environment. Further, the role of the ECM in human disease and pathogenesis is discussed as well as the use of model organisms in elucidating ECM function.

The chick embryo chorioallantoic membrane (CAM) is an extraembryonic membrane which serves as a gas exchange surface and its function is supported by a dense capillary network. Because of its extensive vascularization and easy accessibility, the CAM has been broadly used to study the morpho-functional aspects of the angiogenesis process in vivo and to investigate the efficacy and mechanisms of action of pro-angiogenic and anti-angiogenic natural and synthetic molecules. The CAM is a suitable site for transplanting tissues, which can survive and develop in the CAM by peripheral anastomoses between graft and original CAM vasculature or by new angiogenic vessels grown from the CAM that invade the graft. While the formation of peripheral anastomoses between host and pre-existing donor vessels is the main, and the most common, mechanism involved in the revascularization of embryonic grafts, the growth of CAM-derived vessels into the graft is only stimulated in tumor grafts. The CAM has long been a favored system for the study of tumor angiogenesis and metastasis, because at this stage the chick immunocompetence system is not fully developed and the conditions for rejection have not been established. Tumors remain avascular for 72 h, after which they are penetrated by new blood vessels and begin a phase of rapid growth. Also, delivery of tumor cells onto the CAM allows the fine study of the effects of tumor derived angiogenic growth factors on blood vessel structure and functionality. The CAM may also used to verify the ability to inhibit the growth of capillaries by implanting tumors onto the CAM and by comparing tumor growth and vascularization with or without the administration of an anti-angiogenic molecule. Other studies using the tumor cells/CAM model have focused on the invasion of the chorionic epithelium and the blood vessels by tumor cells. The cells invade the epithelium and the mesenchymal connective tissue below, where they are found in the form of a densebed of blood vessels, which is a target for intravasation.

International Review of Cell & Molecular Biology presents current advances and comprehensive reviews in cell biology—both plant and animal. Articles address structure and control of gene expression, nucleocytoplasmic interactions, control of cell development and differentiation, and cell transformation and growth.• Authored by some of the foremost scientists in the field • Provides up-to-date information and directions for future research • Valuable reference material for advanced undergraduates, graduate students and professional scientists

Apoptosis, Cell Signaling, and Human Diseases: Molecular Mechanisms, Volumes 1 and 2, present a concise synthesis of recent developments in the understanding of both cell survival and apoptotic pathways. Particular attention is given to apoptosis in human diseases, such as different forms of cancer and neurodegenerative diseases. These comprehensive volumes integrate the most innovative and current findings from several related disciplines of scientific research, including pathology, genetics, virology, cell biology, immunology, and molecular biology. Volume 1 is divided into two sections: “Malignant Transformation and Metastasis” and “Molecular Basis of Disease Therapy.” Volume 2 follows a similar structure and is divided into sections entitled “Kinases and Phosphate” and “Molecular Basis of Cell Death.” All of the contributors are at the forefront of scientific discovery, and the reviews they present systemically examine the most exciting and innovative aspects of their particular areas of expertise. Researchers will find these volumes of major benefit as they search for novel and more effective treatments for human diseases.

Morphogenesis is the set of processes that generate shape and form in the embryo- an important area within developmental biology. An exciting and up to the minute account of the very latest research into the factors that create biological form, Mechanisms of Morphogenesis is a text reference on the mechanisms of cell and tissue morphogenesis in a diverse array of organisms including prokaryotes, animals, plants and fungi. By combining hard data with computer modelling, this book will equip readers with a much broader understanding of the scope of modern research than is otherwise available. The book focuses on the ways in which the genetic programme is translated to generate cell shape, to direct cell migration, and to produce the shape, form and rates of growth of the various tissues. Each topic is illustrated with experimental data from real systems, with particular reference to gaps in current knowledge and pointers to future research.• Includes over 200 four-color figures • Offers an integrated view of theoretical developmental biology and computer modelling with laboratory-based discoveries • Covers experimental techniques as a guide to the reader • Organized around principles and mechanisms, using them to integrate discoveries from a range of organisms and systems

International Review of Cytology presents current advances and comprehensive reviews in cell biology – both plant and animal. Authored by some of the foremost scientists in the field, each volume provides up-to-date information and directions for future research. Articles in this volume address the Keratins of the human hair follicle; calcium channels and Ca2+ fluctuations in sperm physiology; genomic imprinting: cis-acting sequences and regional control; insulin-like growth factor signaling in fishes; cell biology of cardiac cushion development.

Epithelial phenotype is a dynamic stage of differentiation that can be modulated during several physiological or pathological events. The rapid conversion to a mesenchymal-like phenotype is called an epithelial-mesenchymal transition (EMT). The Rise and Fall of Epithelial Phenotype is the first book to comprehensively introduce the concept of EMT. The first part of this volume describes main examples and models and explains their physiological relevance. These examples include hydra morphogenesis, gastrulation in mouse, drosophila and sea urchin, as well as neural crest cell migration and heart morphogenesis in vertebrates. Part two reviews in detail, specific EMT molecular pathways covering extracellular induction, transduction and transcription response and modulation of cell-cell adhesion structures. It emphasizes new specific pathways with potential medical applications. EMTs can also be linked to pathological events such as wound healing and cancer progression, as detailed in this section of the book.

Current Topics in Developmental Biology provides a comprehensive survey of the major topics in the field of developmental biology. The volumes are valuable to researchers in animal and plant development, as well as to students and professionals who want an introduction to cellular and molecular mechanisms of development. The series has recently passed its 30-year mark, making it the longest-running forum for contemporary issues in developmental biology. This volume contains ten important contributions from leading minds in developmental biology.• Series Editor Gerald Schatten is one of the leading minds in reproductive and developmental science • Presents major contemporary issues and astonishing discoveries at the forefront of modern developmental biology, stem cells and cloning, and regenerative medicine• The longest-running forum for current issues in developmental biology with over 30 years of coverage

International Review of Cytology presents current advances and comprehensive reviews in cell biology-both plant and animal. Articles address structure and control of gene expression, nucleocytoplasmic interactions, control of cell development and differentiation, and cell transformation and growth. Authored by some of the foremost scientists in the field, each volume provides up-to-date information and directions for future research.Key Features• Cellular and Molecular Biology of Capacitation and Acrosome Reaction in Spermatozoa• Growth Factors and Epithelial-Stromal Interactions in Prostate Cancer Development• PCR-Detected Genome Polymorphism in Malignant Cell Growth• Cellulose Microfibrils in Plants: Biosynthesis, Deposition, and Integration into the Cell Wall• Cell Biology of Peroxisomes and Their Characteristics in Aquatic Organisms• Cellular Responses to Vasectomy

One of the most intriguing discoveries in molecular biology in the last decade is the existence of an evolutionary conserved and essential system, consisting of molecular chaperones and folding catalysts, which promotes the folding of the proteins in the cell. This text summarizes our current knowledge of the cellular roles, the regulation and the

The present volume focuses on microbial invasion strategies of pathogen uptake. An accompanying volume (Vol. 5) in the series presents the phagocytic process from the viewpiont of the host cell. This field of study is growing rapidly after a somewhat slow start over recent decades. This collection of invited chapters attempts to reflect current research and brings together cell biologists, microbiologists, and immunologists wiht disthemes, hopefully like a symphony rather than a boring catalogue. It will be evident that editorial bias favors intracellular parasitism and medically important organisms. The neutrophil is far more than a supporting player to the macrophage and some attempt is made to remind the reader of some of its unique skills. To retain a manageable size, the emphasis is on relatively early events such as mutual recognition, cell entry, and response, rather than on longterm changes in gene expression by either host cell or pahtogen. Viruses are excluded not because of lack of importance but because of somewhat different research approaches, although it is becoming increasingly clear that large viruses (e.g. Vaccinia) and Listeria monocytogenes, share common strategies in invasion and intercellular spread.

The last decade has seen an explosion in our understanding of how bacterial pathogens trick, cajole, usurp and parasitize their various hosts. This renaissance is due to the convergence of molecular and cellular techniques with the power of microbial genetics. The purpose of this volume is to introduce recent advances in understanding selected systems chosen from both plant and animal hosts of bacterial pathogens. This somewhat nonobvious choice of topics was spurred by the recent findings, detailed by several conributors to this volume, of common systems used to secrete virulence factors from pathogens of both plants and animals. These serendipitous findings underscored the importance of basic research approaches to parallel problems in biology. More importantly, they brought together investigators who may not have otherwise become conversant with each other's experimental systems. I, for one, find the kinds of synergism reflected in a volume of this sort to be one of the most pleasant aspects of science and hope that the reader, whether a newcomer to the field or an expert, can find a new slant to old problems in the reviews contained h,E:lre. It was, however, necessary to limit volume length, and this has forced the exclusion of a number of fascinating bacterial pathosystems.