Fungal Morphogenesis

Fungal Morphogenesis brings together, for the first time, the full scope of fungal developmental biology.

Infectious fungal diseases continue to take their toll in terms of human suffering and enormous economic losses. Invasive infections by opportunistic fungal pathogens are a major cause of morbidity and mortality in immuno-compromised individuals. At the same time, plant pathogenic fungi have devastating effects on crop production and human health. New strategies for antifungal control are required to meet the challenges posed by these agents, and such approaches can only be developed through the identification of novel biochemical and molecular targets. However, in contrast to bacterial pathogens, fungi display a wealth of “lifestyles” and modes of infection. This diversity makes it extremely difficult to identify individual, evolutionarily conserved virulence determinants and represents a major stumbling block in the search for common antifungal targets. In order to activate the infection programme, all fungal pathogens must undergo appropriate developmental transitions that involve cellular differentiation and the introduction of a new morphogenetic programme. How growth, cell cycle progression and morphogenesis are co-ordinately regulated during development has been an active area of research in fungal model systems such as budding and fission yeast. By contrast, we have only limited knowledge of how these developmental processes shape fungal pathogenicity, or of the role of the cell cycle and morphogenesis regulators as true virulence factors. This book combines state-of-the-art expertise from diverse pathogen model systems to update our current understanding of the regulation of fungal morphogenesis as a key determinant of pathogenicity in fungi.

Infectious fungal diseases continue to take their toll in terms of human suffering and enormous economic losses. Invasive infections by opportunistic fungal pathogens are a major cause of morbidity and mortality in immuno-compromised individuals. At the same time, plant pathogenic fungi have devastating effects on crop production and human health. New strategies for antifungal control are required to meet the challenges posed by these agents, and such approaches can only be developed through the identification of novel biochemical and molecular targets. However, in contrast to bacterial pathogens, fungi display a wealth of “lifestyles” and modes of infection. This diversity makes it extremely difficult to identify individual, evolutionarily conserved virulence determinants and represents a major stumbling block in the search for common antifungal targets. In order to activate the infection programme, all fungal pathogens must undergo appropriate developmental transitions that involve cellular differentiation and the introduction of a new morphogenetic programme. How growth, cell cycle progression and morphogenesis are co-ordinately regulated during development has been an active area of research in fungal model systems such as budding and fission yeast. By contrast, we have only limited knowledge of how these developmental processes shape fungal pathogenicity, or of the role of the cell cycle and morphogenesis regulators as true virulence factors. This book combines state-of-the-art expertise from diverse pathogen model systems to update our current understanding of the regulation of fungal morphogenesis as a key determinant of pathogenicity in fungi.

Account of the developmental biology of fungi.

The tendency of fungi pathogenic for humans to have shapes in tissue distinct from their usual saprophytic morphologies has fascinated the pathologist and medical mycologist for almost a century. A primary rea son for this fascination is the possibility that fungal duality of form, or dimorphism, may be an important virulence factor that allows the zoo pathogenic fungus to survive host defenses. A second reason relates to the desire to gain basic insights into the regulation of cellular develop ment and morphogenesis among the etiological agents of human mycoses. Many excellent treatises have appeared within the recent past dealing with fungal dimorphism. However, it is becoming increasingly clear that it may be beyond the capability of one or a few authors to review this subject adequately. Instead, the ever-increasing volume ofliterature asso ciated with fungal dimorphism and the diversity offungi now recognized to exhibit a type of dimorphism suggest that a volume comprised of con tributions by numerous researchers may be more appropriate. This per ception provided me with the motivation to compile a multiauthor volume.

Fungal dimorphism is a topic that sounds inherently too rarified to attract more than a specialist audience. Yet some 230 individuals representing an eclectic mixture of interests, from basic science to medical practice, gathered in Churchill College, Cambridge in Semptember 1992 for a meeting devoted only to this subject. The symposium was the fourth in a series "Topics in Mycology" to be jointly organized by the Janssen Research Foundation and the International Society for Human and Animal Mycology. The participants enjoyed a rich and varied diet of oral presentations and poster displays in the field of fungal morphogenesis. This book sets down in print the material presented at the dimorphism symposium. We think that the high quality of these papers conveys very well the flavor of what was an excellent meeting. The selection of contributions in this volume covers very wide ground indeed. Chapters devoted to some non-pathogenic fungi are included, because the scientific basis of morphological development belongs to the fields of cellular and molecular biology: it does not recognize the boundary imposed by considerations of virulence of a fungus for a human host. Yet morphogenetic change in those fungi that do cause human disease frequently appears to be a component of the pathological process: many important pathogens change from a hyphal form in the external environment to a round form in infected tissues. This relationship between dimorphism and pathogenicity is the point of contact between pure biology and medicine.

It was not until recent years that the study of polyamines, their mechanisms of synthesis, and the roles they play in metabolism have flourished, becoming a fertile field of intense research. Polyamines in Fungi: Their Distribution, Metabolism, and Role in Cell Differentiation and Morphogenesis provides a complete overview of its topic. It is the first and only book to describe and analyze the roles of polyamines in fungi and compare them with the roles of polyamines in higher eukaryotes. The book contains data on the distribution of polyamines, their physiological functions, mechanism of synthesis and regulation, phylogenetic analyses of the enzymes involved in their synthesis, their use as possible targets for the control of fungal diseases, and possible biotechnological and medical applications. Based on work generated by the authors in their laboratory over many years, the book contains all the basic information to understand the similarities and differences of polyamine metabolism in eukaryotes. Additionally, it provides an up-to-date account of the contribution and potential use of fungi as models for the basic study of polyamines in comparison with other organisms.