Agaricales Research Papers - Academia.edu (original) (raw)

Mushrooms are rapidly becoming recognized as a promising source of novel proteins. Several proteins showing unique features have been isolated, including lectins, lignocellulolytic enzymes, protease inhibitors and hydrophobins. They can offer solutions to several medical and biotechnological problems such as microbial drug resistance, low crop yields, and demands for renewable energy. Large-scale production and industrial application of some fungal proteins proves their biotechnological potential and establishes higher fungi as a valuable, although relatively unexplored, source of unique proteins. This review provides the first comprehensive overview of known proteins from mushrooms, describes the process of acquiring a new bioactive protein, and provides an overview of current and anticipated applications of these proteins across biotechnology, medicine and agriculture. Bioactives from higher fungi (see Glossary) Fungi (yeasts, molds and mushrooms) have diverse morphological, physiological and ecological characteristics that support their diverse lifestyles that include parasites, saprotrophs that degrade dead organic matter mainly of plant origin, and symbionts that form lichens and mycorrhyzae. These specific interspecies interactions, as well as competition for resources and defense against pathogenic and predatory organisms in their environment, depend on the production of a wide range of bioactive substances. It is estimated that there are 140 000 fungal species (also called higher fungi), that form mushrooms and belong to phyla Ascomycetes and Basidiomycetes [1]. Of these, around 2000 species are edible, and about 200 have traditionally been gathered for food or for medicinal and other preparations. Only 10% of mushroom-forming species are known, making them an enormous untapped pool of potentially useful substances [2,3]. The resistance of microorganisms to existing drugs and a large number of untreatable diseases demands new approaches in human and veterinary medicine. More effective natural resource usage is needed, including higher crop yields, environmentally friendlier plant protection, and use of renewable energy resources. Fungi have already proven useful in many medical and biotechnological applications because of their unique metabolic activities, and as a source of degradative enzymes and secondary metabolites [4]. Review Glossary Ascomycetes: commonly known as the sac fungi, they include most yeasts and molds, as well as morels and truffles. They have many benefits for medicine (source of medicinal compounds such as antibiotics) and are extensively used in the food industry (cheese, bread, alcoholic beverages and fermented sauces). They are also plant and animal/human pathogens. Basidiomycetes: often referred to as higher fungi, they include most mushrooms including chanterelles, puffballs, boletes, bracket fungi, jelly fungi, stinkhorns, and others, as well as the plant pathogens smuts and rusts, and some yeasts, including the human pathogen yeast Cryptococcus. Biosensor: an analytical device incorporating a biological recognition element (e.g. enzyme, antibody, microorganism, tissue or lectin) that is intimately associated or integrated within a physicochemical transducer (e.g. optical, electrochemical, calorimetric, acoustic, piezoelectric, magnetic or micromechanical), which detects the change in recognition element upon sensing a signal. They offer a real-time, simple, fast and low-cost method for identification, detection and characterization of biological matter, therefore, biosensors are widely used in medical, industrial, environmental and food analysis. Biotin-binding protein: Biotin is a water-soluble B-complex vitamin essential in many biological processes. Proteins avidin (animal) and streptavidin (bacterial) bind biotin with high affinity; the highest known in nature between a ligand and a protein. This interaction is widely used in medical, biological, biochemical and biotechnological applications, as well as in chemistry and physics. Cellulose: the major constituent of plant biomass; a homopolysaccharide composed of b-D-glucopyranose units linked by b-1,4-glycosidic bonds and degraded by cellulases. Glycosidases: (glycoside hydrolases) catalyze hydrolysis of glycosidic bonds. They are classified according to substrate specificity and molecular mechanism by the IUBMB Enzyme Nomenclature system. The Carbohydrate-Active Enzymes database (CAZy) provides a classification based on sequence homology (http://www.cazy.org/Glycoside-Hydrolases.html). Hemicellulose: heterogeneous polymer composed of pentoses (D-xylose and Darabinose), hexoses (D-mannose, D-glucose and D-galactose) and sugar acids. The main carbohydrate is xylan. Hemicellulose is degraded by hemicellulases, named xylanases in the case of xylan. Higher fungi: (also macrofungi) are those species in the kingdom of fungi in which hyphae with two nuclei constitute a significant part of the life cycle and belong to subkingdom Dikarya. Higher fungi form mushrooms, the common name for sexual fruiting bodies termed basidiocarps for Basidiomycetes and ascocarps for Ascomycetes. Immunomodulatory: stimulate, suppress or modulate any of the components of the immune system including both the innate and adaptive immune response. Laccase: blue multi-copper oxidase that catalyzes the four-electron reduction of oxygen to water, coupled with the oxidation of small organic substrates (generally ortho-and para-diphenols and aromatic amines). Lectin: (previously also hemagglutinin) a protein that binds carbohydrates with high specificity without modifying them. Their physiological functions are many, with the common denominator that they act as recognition molecules in cell-molecule and cell-cell interactions. Lectin microarray: different lectins are immobilized on a single chip in an array format, which, after hybridization and analysis of the spot-binding pattern, provides information on the carbohydrate composition of the applied sample. Lignin: this most abundant form of aromatic carbon in the biosphere is a complex high molecular weight, heterogeneous, 3D polymer, which provides rigidity, support and protection to plants. Lignin cannot be cleaved by hydrolytic enzymes. Its degradation is nonspecific and requires oxidative enzymes and/or small mediators or factors such as radicals. Mushroom: a distinctive fruiting body of a macrofungus, (large enough to be seen by naked eye and be picked by hand) that can be either above ground (e.g. button mushrooms) or below ground (e.g. truffles).