In ancient times foods fermented with lactic acid bacteria already constituted an important part of the human diet. From then on, lactic acid bacteria have played an essential role in the preservation of food raw materials and have contributed to the nutritional, organoleptic and health properties of human food products and animal feed. The important function that lactic acid bacteria still have in the production of foods all over the world has resulted in a growing scientific interest in these micro-organisms by academic research groups as well as by industry. During the last 15 years, this research has been stimulated by major internationally coordinated funding efforts that have resulted in a variety of important scientific breakthroughs and have led to new applications. Written by international experts in the field, this issue of Antonie van Leeuwenhoek documents these developments with respect to genetics, metabolism and the application of lactic acid bacteria for industrial and potential medical applications. In this book the first complete genome of a lactic acid bacterium is presented. The book will serve as a reference source and also as an indispensable source of information for further development and exploration of the field.

The Tohoku University Graduate School of Dentistry first introduced the concept of "Interface Oral Health Science", designed to establish and maintain healthy oral cavities, which are home to a number of mixed systems. Included in those systems are: (1) host tissues such as teeth, mucosa, muscle and bone, (2) parasites and microorganisms cohabiting the surfaces of the oral cavity and (3) biomaterials that are used for the rehabilitation of oral functions. In addition, (4) these systems are subject to severe and complex mechanical forces. Therefore, it is critical to promote dental studies that integrate a wide range of interdisciplinary research as medicine, agriculture, material science, engineering, and pharmacology. With this incentive, international symposiums for interface oral health science have been held several times in the past. The concept has since refined and expanded, the result being the "Biosis-Abiosis Intelligent Interface," and projects aiming at the creation of highly functional and autonomic intelligent interfaces are ongoing. This book brings together a number of studies on incentives and projects by leading authors. Topics include biosis-abiosis interface of dental implants, biomaterials in interface science, biomedical engineering interface and cell manipulation and tissue regeneration. Readers not only from the field of dentistry but also many related areas will find this book a valuable resource.

Marsh and Martins' Oral Microbiology continues to offer the essentials of oral microbiology in an easy-to-read, readily digestible format. Commencing with a description of the healthy mouth and the properties of the resident oral microbiota, the new edition of this popular textbook then explores the formation and consequences of plaque development, plaque-mediated disease, orofacial infection, antimicrobial agents and prophylaxis, orofacial fungal and viral infections, and the relationship between oral microbiota and systemic disease. The book is completed by a chapter on infection control. Each chapter is succinct and includes essential information in a concise format - thereby saving the reader valuable time. The book is presented with an abundance of tables, photographs and artworks to make the subject as engaging as possible - numerous 'Key Point' boxes aid retention. Marsh and Martins' Oral Microbiology is suitable for undergraduate and postgraduate dental students, research workers, and a wide range of clinical dental professionals. Successfully describes the complex relationship between the resident oral microbiota and the host in health and disease Retains a unique ecological approach to the subject which provides a clear set of principles to explain whether the microbiota will have a beneficial or an adverse relationship with the host at a particular site Exploration of the biological and clinical significance of the oral microbiota in the form of a biofilm on dental and mucosal surfaces Completely updated throughout by a new author team! Self-assessment questions in each chapter allow readers to monitor their progress Updated design with 'Key Points' throughout aids learning Reflects the impact that the genomic era has had on the field Expanded sections on infection control as well as therapeutic and prophylactic antibiotic use New sections on the benefits of the resident oral microbiota and on current concepts of factors driving dysbiosis in periodontal disease New chapter on the emerging role of oral microorganisms in systemic diseases

Epstein-Barr virus (EBV) is one of the most widespread human viruses, with over 80% of the general population exposed by young adulthood, as determined by antibody studies. Initial infection usu ally occurs during childhood or the teenage years. It is clear that, de pending on the age of the recipient, clinical manifestations of the primary infection can vary. It has been known for 20 years that EBV is the etiologic agent of acute infectious mononucleosis (IM) and is also closely associated with African Burkitt's lymphoma (BL) and naso it is a pharyngeal carcinoma (NPC). There is increasing evidence that factor in the etiology of B-celllymphomas, which arise at a high fre quency in immunodeficient populations. EBV may also contribute to the development of autoimmune disease. Thus, this virus continues to attract world-wide attention. The major target cell for EBV infection has now been conclusively identified as the complement receptor-type 2 (CR2), the Cd/Cdg 3 3 receptor on B lymphocyte. It is apparent, however, that other cells also can become infected by EBV, such as epithelial cells in the parotid gland and other epithelial cells in the upper respiratory tract. This might help account for the EBV-assodated carcinomas of the upper respiratory tract. The first in a series of international symposia on EBV -associated diseases focused primarily on Burkitt's-type lymphomas or on NPC (Kyoto 1977; Dusseldorf 1980; Kuala Lumpur 1982) and emphasized mainly the clinical elements of these diseases. Subsequent symposia (Loutraki, 1984; St."

Food Preservation and Safety of Natural Products addresses the most common causes of food spoilage that create significant loss to global food production while also discussing how food serves as a vehicle for the transmission of pathogenic microorganisms responsible for mild to debilitating health conditions in humans. The book provides essential information for food safety professionals on issues relating to foodborne diseases and offers potential solutions by presenting various methods of incorporating natural products in food production to prevent the spread of foodborne pathogenic organisms. The demand for green consumerism and consumers general distaste for synthetic food additives poses a serious challenge to food safety and preservation. Natural products are used as green and sustainable source of bioactive compounds that can be applied in various fields including food. The use of plant and other natural products in food preservation is on the rise, hence this book reviews microbial mediated food spoilage, foodborne pathogens and food contamination and offers applications of natural products in food preservation.

The Hippo signaling pathway is rapidly gaining recognition as an important player in organ size control and tumorigenesis, and many leading scientists are showing increased interest in this growing field and it's relation to cancer. The chapters in this volume cover virtually all aspects of tumor biology, because members of the Hippo Pathway have been associated with numerous well-established cell signaling pathways, just to name a few; Ras, Wnt, TGFbeta and p53. Moreover, Hippo signaling is not solely involved in regulating "classic" tumor characteristics such as cell proliferation, survival and growth, but is also diversely involved in cell-autonomous and non-cell-autonomous differentiation, migration and organ size control. The primary audience are researchers interested in basic science in the areas of tumor suppression, cell cycle and size regulation, development and differentiation.

Herpes Simplex Virus: Methods and Protocols provides a wide collection of protocols employed in various levels of herpes virus research, including basic protocols on growing viruses in cell culture and cloning, manipulating and preparing viral DNA. Other chapters describe approaches to design and apply HSV-1 vectors for vaccination, cancer and gene therapy or to study specific aspects of HSV-1 biology such as latency, intracellular transport and protein-protein interaction. Procedures for structural analyses, microscopy, proteomics and testing of antivirals are included as well. Written in the highly successful Methods in Molecular Biology series format, chapters include introductions to their respective topics, lists of the necessary materials and reagents, step-by-step, readily reproducible laboratory protocols and tips on troubleshooting and avoiding known pitfalls. Practical and authoritative, Herpes Simplex Virus: Methods and Protocols will aid new researchers in the field of herpes virology as well as those experienced investigators wishing to embark on new techniques.

Genetically Modified and Irradiated Food: Controversial Issues: Facts versus Perceptions explains the technologies used in these processes so they can be understood by those in general public health, scientific organizations, politicians and opinion makers/policymakers. The facts presented include a massive amount of scientific evidence that these technologies are safe and can be beneficial. Because the world is facing a future with an increasing number of people, new technologies are needed to ensure enough safe and healthy food, thus technologies that have the potential to dramatically increase the availability of safe and healthy food should be welcomed by everybody.

The microbiology of drinking water remains an important worldwide concern despite modem progress in science and engineering. Countries that are more technologically advanced have experienced a significant reduction in water borne morbidity within the last 100 years: This reduction has been achieved through the application of effective technologies for the treatment, disinfec tion, and distribution of potable water. However, morbidity resulting from the ingestion of contaminated water persists globally, and the available ep idemiological evidence (Waterborne Diseases in the United States, G. F. Craun, ed. , 1986, CRC Press) demonstrates a dramatic increase in the number of waterborne outbreaks and individual cases within the United States since the mid-1960s. In addition, it should also be noted that the incidence of water borne outbreaks of unknown etiology and those caused by "new" pathogens, such as Campylobaeter sp. , is also increasing in the United States. Although it might be debated whether these increases are real or an artifact resulting from more efficient reporting, it is clear that waterborne morbidity cannot be ignored in the industrialized world. More significantly, it represents one of the most important causes of illness within developing countries. Approxi mately one-half the world's population experiences diseases that are the direct consequence of drinking polluted water. Such illnesses are the primary cause of infant mortality in many Third World countries.

John Sinclair and a panel of expert investigators present a comprehensive collection of cellular and molecular techniques for the analysis of cytomegalovirus (CMV) biology and its pathogenetic mechanisms. The methods-all described in step-by-step detail with ready reproducibility in mind-range from basic virus culture to complex molecular analysis of CMV structure and function. Included are methods for CMV detection using both immunological and biological techniques, methods for analyzing fundamental aspects of the CMV infection cycle, and methods for analyzing T cell response to cytomegalovirus infection in the human host. Comprehensive and state-of-the-art, Cytomegalovirus Protocols provides investigators with a collection of the key methods that are illuminating not only the basic biology of this complex and intriguing human herpesvirus, but also its significant role in human infectious diseases and their emergent therapies.

The present volume of Epigenetics and Human Health is devoted to the patho-epigenetics of viral and microbial infections, an exiting new field of disease-related epigenetic research. As recognized during the past years, epigenetic reprogramming of pathogen and host genome functions - the latter frequently induced by pathogens - plays an important role in many infectious processes. Beyond their immediate relevance for pathogen proliferation and obligatorily associated symptoms, such alterations frequently contribute to severe additional complications, such as the development of immunodeficiency, cancer and various chronic disorders. This holds in particular for epigenetic dysregulation of host gene expression induced by latent infections. The present book summarizes current knowledge of the mechanisms underlying epigenetic changes caused by viral, bacterial, fungal and protozoan infections and their impact on human health.

Mycobacteria is divided into two volumes. The first volume deals with the basic biology of mycobacteria. With its emphasis on the state of the art outlook, this volume includes taxonomy and molecular biology of mycobacteria, modern approaches for detection of mycobacteria, and immunology and immunization against tuberculosis. The second volume covers drug trestments for mycobacteria anad tuberculosis. It outlines trends of discovery and development of chemotherapy, starting from the mid-50's to present day uses of chemotherapy in treating AIDS, drug-resistant tuberculosis, and other non-tuberculosis mycobacterial diseases.

In recent years there have been various discoveries connecting inflammation and lung cancer and clearly there is growing interest in this area of cancer research. The link between unresolved inflammation and cancer has been well established with estimates that 15% of cancer deaths are inflammation-related. Evidence for this link includes the following: a) some inflammatory diseases are associated with increased risk of cancer development; b) inflammatory mediators are present surrounding and within most tumors; c) overexpression of inflammatory cytokines increases cancer development and progression in murine studies; d) inhibition of inflammatory mediators decreases cancer development and progression; and e) the use of non-steroidal anti-inflammatory drugs (NSAIDs) has been found to decrease cancer incidence and delay progression. The volume will present aspects of the inflammatory tumor microenvironment (TME), its many roles in tumor progression and metastasis, including creation of a hypoxic environment, increased angiogenesis and invasion, changes in expression of micro-RNAs (miRNAs) and an increase in a stem cell phenotype. The book will also cover the mechanisms of inflammatory mediators. Chronic overexpression of inflammatory mediators in the TME, as seen in smokers and patients with non-small cell lung cancer (NSCLC), can also lead to increased tumor initiation, progression, invasion and metastasis. The volume will provide a comprehensive perspective of the latest findings and summaries of progress made regarding inflammation and its connection to lung cancer.

The genus Pseudomonas represents a large group of medically and envi ronmentally important bacteria. Interest in these bacteria is reflected in the extensive number of publications devoted to original research, re views, and books on this subject. In this volume selected areas of Pseu domonas research are presented in depth by persons who have been active in their fields over many years. The extensive reviews presented are an effort to provide a balanced perspective in a number of areas not readily available in the current literature. In the style of the previous Biotechnology Handbooks most of these topics have not been reviewed at all, and several are also presented from a new direction. For example, in addition to structural and compositional aspects, the chapter on lipids provides shifts in lipid parameters that result from environmental changes. This information will be invaluable to a cross section of Pseu domonas researchers in pathogenesis and bioremediation. The chapters presented include basic aspects of plasmid biology and carbohydrate metabolism and regulation. A major emphasis is placed on the Pseudomonas aeruginosa cell surface. Chapters cover lipo polysaccharide, capsular polysaccharide and alginate, the outer mem brane, transport systems, and the flagellum. Uptake of iron is also neces sarily an important portion of the chapter on iron metabolism."

To the uninitiated, the genus Clostridium is likely more to be associated with disease than biotechnology. In this volume, we have sought to remedy this misconception by compiling aseries of chapters which, together, provide a practically-oriented handbook of the biotechnologie potential of the genus. Clostridium is a broad grouping of organisms that together undertake a myriad of biocatalytic reactions. In the first two chapters, the reader is introduced to this diversity, both taxonomically and physiologically. In the following chapter, the current state of genetic analysis of members of the genus is reviewed. The remaining chapters concentrate on specific, exploit able aspects of individual Clostridium species-highlighting their range of unique capabilities (of potential or recognized industrial value), particu larly in the areas of biotransformation, enzymology, and the production of chemical fuels. Fittingly, the final chapter demonstrates that even the most toxic of the clostridia can be of therapeutic value. The contributors to this volume reflect the trans national interest in Clostridium, and we are indebted to each of them for making this volume possible. We particularly wish to acknowledge the contributions, both to this volume and to microbiology in general, of Dr. Elizabeth Cato, who, sadly, died shortly be fore publication ofthis volume. Finally, we would like to join the authors in recommending closer and wider consideration of the attributes and capabilities of this genus."

Recently, there has been an upsurge in microbial infections. Extensive and inappropriate usage of antimicrobial drugs in treating infections has led to the evolution of a resistant strain of microorganisms and irreversible immunosuppression in humans. Medical institutions and hospitals require solutions to combat these contagions in order to avoid future epidemics. Strategies to Overcome Superbug Invasions: Emerging Research and Opportunities highlights current research and potential strategies to prevent the emergence and re-emergence of drug-resistant pathogenic microbial strains. The content within this publication examines biosensing, global initiatives, nanomaterials, and alternative therapies. It is designed for microbiologists, biotechnologists, pharmacists, pharmacologists, virologists, formulation scientists, infectious disease specialists, government officials, policymakers, healthcare practitioners, doctors, nurses, hospital directors, researchers, surgeons, and academicians who are seeking research on innovative solutions for multi-drug-resistant infections.

2. The Translational Machinery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Translation Initiation in Prokaryotes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Translation Initiation in Eukaryotes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 14 Translation Elongation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Translation Termination in Prokaryotes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Translation Termination in Eukaryotes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Error Correction in Translation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 A Structural Basis of Error Correction in Translation . . . . . . . . . . . . . . . . . . . . . . . . . . 20 Ribosome Editing: A Failsafe Error Correction Mechanism . . . . . . . . . . . . . . . . 22 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 3. Errors During Elongation Can Cause Translational 29 Frameshifting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Spontaneous Frameshifting Versus Programmed Frameshifting . . . . . . . . . . 30 Spontaneous Frameshifts Can Be Induced at Specific Codons . . . . . . . . . . . . 31 4. Programmed +1 Frameshifting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 The pifE Gene of E. coli . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 Using the pifE System to Study General Frameshifting in E. coli . . . . . . . . 46 Ty Retrotransposons in Yeast . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 Frameshifting in Retrotransposon Ty1 Occurs by tRNA Slippage . . . . . . . 48 Frameshifting in Retrotransposon Ty3 Occurs by Out-of-Frame Binding of tRNA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 The Rat Ornithine Decarboxylase Antizyme Gene . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62 5. Programmed -1 Frameshifting in Eukaryotes . . . . . . . . . . . . . . . . . . . . . . . . . . . 69 Programmed -1 Frameshifting in Eukaryotes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69 -1 Frameshifting Occurs on a "Slippery Heptamer" . . . . . . . . . . . . . . . . . . . . . . . . . . . 71 The Simultaneous-Slippage Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72 of -1 Frameshifting by a Downstream Pseudoknot . . . . . . . . . . 77 Stimulation Does the Pseudoknot Only Block Passage of the Ribosome? . . . . . . . . . .

Virus Variability and Impact on Epidemiology and Control of Diseases E. Kurstak and A. Hossain I. INTRODUCTION An important number of virus infections and their epidemic developments demonstrate that ineffec tiveness of prevention measures is often due to the mutation rate and variability of viruses (Kurstak et al., 1984, 1987). The new human immunodeficiency retroviruses and old influenza viruses are only one among several examples of virus variation that prevent, or make very difficult. the production of reliable vaccines. It could be stated that the most important factor limiting the effectiveness of vaccines against virus infections is apparently virus variation. Not much is, how ever, known about the factors influencing and responsible for the dramatically diverse patterns of virus variability. II. MUTATION RATE AND VARIABILITY OF HUMAN AND ANIMAL VIRUSES Mutation is undoubtedly the primary source of variation, and several reports in the literature suggest that extreme variability of some viruses may be a consequence of an unusually high mutation rate (Holland et al., 1982; Domingo et al., 1985; Smith and Inglis, 1987). The mutation rate of a virus is defined as the probability that during a single replication of the virus genome a particular nucleotide position is altered through substitution, deletion, insertion. or recombination. Different techniques have been utilized to measure virus mutation rates, and these have been noted in the extent of application to different viruses."

This volume reviews the current state of research concerning bacterial virulence factors and the infection biology of Helicobacter pylori, which is the leading cause of peptic ulcers and gastric cancer worldwide. The chapters include cutting-edge findings on this fascinating microbe and discuss the general strategies of H. pylori infection and persistence, news on important H. pylori virulence factors, crosstalk with the microbiota, hot novel models and signaling mechanisms, risk factors of gastric disease and stomach cancer, and the impact of H. pylori infection on non-gastric diseases. Written by internationally respected scientists, this book will appeal to clinicians, researchers and advanced students alike.

Hantaviruses are found world-wide and are associated with two severe disease syndromes, hemorrhagic fever and hantavirus pulmonary syndrome. The recent studies in this volume provide a basis for understanding the high human pathogenicity of theses viruses and their continued maintenance and transmission within rodent populations.

-Integration of Systems Biology with Bioprocess Engineering: L-Threonine Production by Systems Metabolic Engineering of Escherichia Coli, By Sang Yup Lee and Jin Hwan Park; -Analysis and Engineering of Metabolic Pathway Fluxes in Corynebacterium glutamicum, By Christoph Wittmann; -Systems Biology of Industrial Microorganisms, Marta Papini, Margarita Salazar, and Jens Nielsen; -De Novo Metabolic Engineering and the Promise of Synthetic DNA, By Daniel Klein-Marcuschamer, Vikramaditya G. Yadav, Adel Ghaderi, and Gregory N. Stephanopoulos; -Systems Biology of Recombinant Protein Production in Bacillus megaterium, Rebekka Biedendieck, Boyke Bunk, Tobias Furich, Ezequiel Franco-Lara, Martina Jahn, and Dieter Jahn; -Extending Synthetic Routes for Oligosaccharides by Enzyme, Substrate and Reaction Engineering; By Jurgen Seibel, Hans-Joachim Jordening, and Klaus Buchholz; -Regeneration of Nicotinamide Coenzymes: Principles and Applications for the Synthesis of Chiral Compounds; By Andrea Weckbecker, Harald Groger, and Werner Hummel;

Biologically active compounds isolated from microorganisms continue to be vital to the development of new drugs and agricultural chemicals. This book was prepared by current and past members of the laboratory of Dr. Satoshi Omura of the Kitasato Institute in Japan. Dr. Omura and his colleagues have discovered and studied a number of important antibiotics, and in their work they have pioneered new methods for screening microbes for interesting and important compounds. This book presents strategies and methods for identifying novel molecules with several types of biological activity. In addition, the book discusses the identification of microbial compounds of agrochemical importance, presents information on chemical screening methods, and concludes with chapters on microbial strain selection, fermentation technology, and genetic engineering of antibiotic-producing microorganisms. This book will be of great interest to scientists working in the very active and competitive fields of antibiotic and agrochemical discovery.

Authoritative investigators active in the discovery, development, and application of biological anti-infective agents concisely review their use and potential in preventing and treating human disease. Focusing on biotherapeutic entities that have been tested in controlled studies, the prominent experts illuminate the scientific underpinnings of their therapeutic power, assess their possible risks in the treatment of infectious diseases, and outline the research needed to better define their effectiveness. In addition, they also consider how biotherapeutic agents may be genetically engineered for maximum intestinal and vaginal production of bioactive substances in vivo. Biotherapeutic Agents and Infectious Diseases brings together all the evidence needed to understand and capitalize on the considerable promise of this significant new class of biotherapeutic entities.

The ability to remember an antigenic encounter for several decades, even for a life time, is one of the fundamental properties of the immune system. This phenomenon known as "immunological memory," is the foundation upon which the concept if vaccination rests. Therefore, understanding the mechanisms by which immunological memory is regulated is of paramount importance. Recent advances in immunology, particularly in the field of innate immunity, suggest that the innate immune system plays fundamental roles in influencing immunological memory. Indeed, emerging evidence suggests that events that occur early, within hours if not minutes of pathogen or vaccine entry profoundly shape the quantity, quality and duration of immunological memory. The present volume assembles a collection of essays from leading experts that span the entire spectrum research from understanding the molecular mechanisms of innate immune recognition, to dendritic cell function, to the generation and maintenance of antigen-specific B and T-cell responses.

Years ago when we were asked to write a book on the present-day knowledge of the molecular biology of poliovirus, we did not expect that such an apparently simple task could involve so much time and effort. Our writing was hampered by the fact that both of us are full time "workers," so that this monograph is mainly a spare time expedience. The main attention of this book focuses on a detailed review of the molecular biology of poliovirus and especially on the advances of the last decade; medical and environmental aspects are only briefly mentioned. Observations from older studies are considered in view of more recent information. Some of the older ob servations provided fundamental insights and paved the way for present day research; too often such data has been neglected or independently rediscovered. Today, poliovirus research has again attracted considerable interest. High points gained within the last few years were the elucidation of the complete nucleotide sequences of the RNAs of the three poliovinls serotypes and the corresponding vaccine strains, the demonstration of genome evolution during transmission of poliovirus in an epidemic, further characterization of the antigenic sites on the virus particle and of the antigenic drift, characterization of alternate conforma tional states of the virion capsid, the development of monoclonal antibodies against some of the virus proteins, observations on the role of the plasma membrane, cytoskeleton, and cytoplasmic membranes as mediators in the virus induced redirection of the synthetic machinery of the host cell, and characteriza"