Fungi

Biology and Applications

Kevin Kavanagh, Kevin Kavanagh

• Editorial: Wiley-Blackwell
• Año: 2017
• ISBN:
  9781119374275
• Edición: 3
• Categoría: Biological Sciences
• Categoría: Microbiology

This newly updated edition covers a wide range of topics relevant to fungal biology, appealing to academia and industry

Fungi are extremely important microorganisms in relation to human and animal wellbeing, the environment, and in industry. The latest edition of the highly successful Fungi: Biology and Applications teaches the basic information required to understand the place of fungi in the world while adding three new chapters that take the study of fungi to the next level. Due to the number of recent developments in fungal biology, expert author Kevin Kavanagh found it necessary to not only update the book as a whole, but to also provide new chapters covering Fungi as Food, Fungi and the Immune Response, and Fungi in the Environment.

Proteomics and genomics are revolutionizing our understanding of fungi and their interaction with the environment and/or the host. Antifungal drug resistance is emerging as a major problem in the treatment of fungal infections. New fungal pathogens of plants are emerging as problems in temperate parts of the world due to the effect of climate change. Fungi: Biology and Applications, Third Edition offers in-depth chapter coverage of these new developments and more—ultimately exposing readers to a wider range of topics than any other existing book on the subject.

• Includes three new chapters, which widen the scope of fungi biology for readers
• Takes account of recent developments in a wide range of areas including proteomics and genomics, antifungal drug resistance, medical mycology, physiology, genetics, and plant pathology
• Provides extra reading at the end of each chapter to facilitate the learning process

Fungi: Biology and Applications is designed for undergraduate students, researchers, and those working with fungi for the first time (postgraduates, industrial scientists).

1
Introduction to Fungal Physiology

Graeme M. Walker and Nia A. White

1.1 Introduction

Fungal physiology refers to the nutrition, metabolism, growth, reproduction, and death of fungal cells. It also generally relates to interaction of fungi with their biotic and abiotic surroundings, including cellular responses to environmental stress. The physiology of fungal cells impacts significantly on the environment, industrial processes, and human health. In relation to ecological aspects, the biogeochemical cycling of carbon in nature would not be possible without the participation of fungi acting as primary decomposers of organic material. Furthermore, in agricultural operations fungi play important roles as mutualistic symbionts, pathogens, and saprophytes, where they mobilize nutrients and affect the physicochemical environment, or can be exploited as agents of biocontrol or as biofertilizers. Fungal metabolism is also responsible for the detoxification of organic pollutants and for bioremediating heavy metals and other recalcitrant chemicals in the environment (including wastewaters and groundwaters). The production of many economically important industrial commodities relies on the exploitation of yeast and fungal metabolism and these include such diverse products as whole foods, food additives, fermented beverages, antibiotics, probiotics, pigments, pharmaceuticals, biofuels, enzymes, vitamins, organic and fatty acids, and sterols. More negatively, fungi can cause considerable disease, spoilage, and decay of important artefacts, commodities, and materials, buildings, and of course food supplies.

In terms of human health, some yeasts and fungi represent major opportunistic life‐threatening pathogens, while others are life‐savers as they provide antimicrobial and chemotherapeutic agents. In modern biotechnology, several yeast species are being exploited as hosts for the expression of human therapeutic proteins following recombinant DNA and gene editing technologies (see Chapter 9). Recently, the application of gene editing using CRISPR/Cas is leading to a revolution in fungal genetic engineering (see Chapter 2). Furthermore, an international synthetic biology research consortium, called Sc‐2.0, has embarked on the construction of a completely synthetic version of Saccharomyces cerevisiae. This would represent the world’s first fully synthetic eukaryotic genome! In addition to the direct industrial exploitation of yeasts and fungi, it is important to note that these organisms, most notably the yeast S. cerevisiae, play increasingly significant roles as model eukaryotic cells in furthering our fundamental knowledge of biological and biomedical science. This is especially the case now that numerous fungal genomes have been completely sequenced and the information gleaned from fungal genomics and proteomics is providing valuable insight into human genetics and heritable disorders. However, knowledge of cell physiology is essential if the functions of many of the currently unknown fungal genes, including “synthetic” ones, are to be fully elucidated.

It is apparent, therefore, that fungi are important organisms for human society, health, and well‐being, and that studies of fungal physiology are very pertinent to our understanding, control, and exploitation of this group of microorganisms. This chapter describes some basic aspects of fungal cell physiology, focusing primarily on nutrition, growth, and metabolism in unicellular yeasts and filamentous fungi.

1.2 Morphology of Yeasts and Fungi

There are a diversity of yeast and fungal cellular morphologies. Most higher fungi are filamentous, yeasts grow as unicells, and some primitive fungi such as the Chytridomycota grow as individual rounded cells or dichotomous branched chains of cells with root‐like rhizoids for attachment to a nutrient resource. Here we consider the most common growth forms, the filamentous fungi and unicellular yeasts.

1.2.1 Filamentous Fungi

The gross morphologies of macrofungi and microfungi are varied and often apparent throughout the environment (Plate 1.1). For example, we can easily recognize a variety of mushrooms and toadstools, the sexual fruiting bodies of certain macrofungi (the higher fungi Ascomycota and Basidiomycota and related forms), during a walk through pasture or woodland. Microfungi (the molds) are also diverse and are often observed on decaying foods and detritus, whereas many, including the colored rusts, smuts, and mildews, are common plant pathogens. Closer inspection of these visible structures, however, reveals that all are composed of aggregated long, branching threads termed hyphae (singular: hypha), organized to support spores for reproduction and dissemination. The hyphae of these aerial structures extend and branch within the supporting substratum as a network, termed a mycelium, from which the apically growing hyphae seek out, exploit, and translocate available nutrients. Apically growing hyphae usually have a relatively constant diameter ranging from 1 to 30 µm or more, depending on fungal species and growth conditions.

Filamentous fungi may be cultivated within the laboratory on a variety of different liquid...