Principles Of Virology Molecular Biology Pathogenesis And Control

[Sean Vaidhyanathan]

Athorough introduction to principles of viral pathogenesis, a broad view of viral evolution, a discussion of how viruses were discovered, and how the discipline of virology came to be are also provided. A variety of special boxes highlight key experiments, background material, caveats, and much more.

The text focuses on concepts and principles and covers not only aspects of molecular biology, but also pathogenesis, evolution, emergence, and control, and will also be a valuable resource for practicing physicians and scientists.

"Thus, we cannot reject the assumption that the effect of the filtered lymph is not due to toxicity, but rather to the ability of the agent to replicate." This quotation from Friedrich Loeffler (1852-1915) opens the first chapter of a new edition of Flint et al.'s textbook Principles of Virology. Molecular Biology, Pathogenesis, and Control of Animal Viruses, a primer that defines and illustrates the basic principles of animal virus biology. Loeffler (1898) was referring to the then still unknown agent responsible for foot-and-mouth disease in cattle, whose etiology he searched for together with Paul Frosch (1860-1928). The choice of these words by Loeffler reflects the complicated history of the science of virology. Although the earliest human records evidence that ancient peoples were aware of the effects of virus infection, and even carried out research into the causes and prevention of viral diseases, viruses have been recognized as distinct biological entities for only a little more than a century. A hundred years of enormous research efforts involving numerous excellent investigators have led to the appreciation that the vast world of viruses encrypts an enormous biologic, genetic and genomic diversity.

A significant part of the virus world consists of animal viruses, an amazing group of infectious agents usually referred to by their ability to cause disease. However, viral pathogenesis is actually fairly rare; rather, the majority of virus infections are silent and do not result in outward signs of disease. Furthermore, viral infection is not a simple process that can be defined by its apparent effects in the host, but instead comprises a very complex, well-regulated and controlled interaction of highly evolved systems. The enormous biological diversity of animal viruses and their multifaceted relationships with their hosts have been finely and skillfully scrutinized in the 20 chapters comprising this book, which is organized into four specific sections: "The science of virology", "Molecular biology", "Pathogenesis", and "Control and evolution". All chapters are well and clearly structured in short subsections that are very readable and easy to follow. Each chapter ends with an updated and expanded list of relevant books, review articles, and selected research papers. Additional references are listed when a particular experiment is featured in a chapter, and colored text boxes highlight general background information, definitions of terms, and discussions of specific experiments. Furthermore, two handy appendices at the end of the book summarize a wealth of information in a condensed format. Appendix A provides a brief description of the reproductive cycles in single cells of viruses that are frequently mentioned in the main text. Appendix B summarizes the pathogenesis of common viruses that infect humans. It also provides a brief description of the major features of viruses and the diseases associated with them, their epidemiology and the disease mechanism for each virus or virus group.

In Part I, "The science of virology", Chapter 1 is a general introduction to the field and discusses how viruses are classified. It makes note of relevant historic events in the development of the field of virology. Chapter 2 is a practical description of general methods for studying animal viruses in the laboratory. Part II, "Molecular biology", reviews the molecular processes that take place within infected host cells. Chapter 3 discusses the Baltimore classification system in detail, which makes it easier to understand the genomic complexities when they are presented in the context of the seven major genome strategies. The other ten chapters of Part II describe the organization of viral genomes, provide an overview of viral strategies for genome replication and mRNA synthesis, discuss the main principles of viral architecture, taking into account that virus particles are vehicles for viral genomes, and describe the broad spectrum of molecular processes that integrate the reproductive cycle of viruses in a single cell. Part III, "Pathogenesis" (Chaps. 14-18), addresses issues related to the interplay between viruses and their host organisms. Chapter 14 constitutes a comprehensive study of viral pathogenesis, including the basic concepts of viral dissemination in the host, viral virulence and epidemiology. Viral infection of the host animal is met by a collection of immune responses that, in turn, induce a series of viral countermeasures to host defenses. In Chap. 15, this dynamic interplay is clearly explained using a combination of text and figures. Once viruses have established themselves in host cells, they can maintain different types of relationships with their hosts, as is described in Chap. 16. This chapter is dedicated to pathogenesis and is followed by two updated chapters dealing with extremely important issues in current virology: the AIDS virus (Chap. 17) and the no less intricate topic of the roles of viruses in both cell transformation and oncogenesis (Chap. 18). The last part, Part IV, "Control and Evolution", presents fundamental aspects in the relationship between humans and viruses. The treatment and control of viral infection are discussed in Chap. 19. Finally, Chap. 20 confronts the reader with two astonishing facts that define the future of virology and thus relevant public health concerns: (i) viruses are permanently evolving, and (ii) new viruses continuously emerge.

We are currently living in the so-called genomic era, a time in which the biology of organisms is evaluated through the prism of molecular biology, and the interactions between infectious agents and their hosts are seen as a dynamic interplay between their genomes. This perspective is thoroughly provided by Principles of Virology, which is highly recommended for students, microbiologists, molecular biologists and physicians interested in the basic principles governing viral biology, the modes of viral interaction with animals, and the ways in which animals respond to infecting viruses.

This is the first book to summarize current knowledge of the family of proteins called porins and consists of chapters authored by recognized researchers in this field. The volume is edited by Roland Benz, from the University of Wrzburg, Germany. Chapter 1, by D. Walthers et al., deals with the regulation of porin expression by the two-component regulatory system EnvZ/OmpR, which controls osmosensing in Escherichia coli. Chapter 2 (G. Schulz) provides an overview of the structure of bacterial porins, while in Chap. 3 J.M. Pags focuses on one of the most important consequences of porin modification in nature: the role of porins in determining antibiotic resistance in gram-negative bacteria. For example, in Pseudomonas aeruginosa, resistance to some antibiotics, including carbapenems, is due to the loss of certain porins, mainly the outer membrane porin OprD, which is the subject of Chap. 4, by R. Hancock and S. Tamber. Chapter 5 discusses the regulation of porin function, which has been studied using a variety of approaches, including molecular biology and electrophysiology, by the authors A. Basl and A. Delcour. In Chap. 6, M. Winterhalter and C. Danelon review the methods of reconstitution of general diffusion pores from the bacterial outer membrane. The following chapter, by E. Sugawara and H. Nikaido, provides experimental evidence concerning the channel-formation ability of OmpA/OprF slow porins. The role of channel-tunnel proteins in relation to drug efflux is the subject of Chap. 8, by C. Andersen. Particularly attention is paid to the channel-tunnel protein TolC, whose structure and function have been well studied by several investigators. Chapter 9, authored by T. Schirmer, provides an example of the role of porins in bacterial nutrition by discussing the structure-function relationships of sugar-specific porins, e.g. maltoporin. The editor, R. Benz, and his co-worker F. Orlik describe in Chap. 10 the functional reconstitution of specific porins (the current subject of research in Benz's laboratory). In Chapter 11, V. Braun and M. Braun review the energy-coupled transport of iron across the outer membrane. The remaining five chapters of the book are devoted to recent knowledge regarding the structure and function of eukaryotic porins, such as the vitamin B12 receptor BtuB (Chap. 12, R. Kadner et al.) and mitochondrial porins (Chap. 13, R. Benz), as well as to their functional roles in mice (Chap. 14, K. Anflous and W. Craigen), intracellular trafficking (Chap. 15, V. De Pinto and A. Messina) and intracellular signalling (Chap. 16, M. Vyssokikh and D. Brdiczka).

This excellent book should be present in all laboratories working in the fields of bacterial outer membranes, bacterial resistance to antibiotics, cell signalling, and intracellular trafficking. In addition, it is suitable for advanced students in microbiology and molecular biology. The information is extremely up-to-date and is supported by high-quality and highly original graphics.

By three billion years ago, life had changed the color of the inland seas; by two billion years ago, the gross composition of the atmosphere; and by one billion years ago, the weather and the climate. All these profound changes were brought about by microorganisms. In turn, the genes and genomes of extant organisms are the result of these ca. four billion years of evolution.

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