Introduction to Mycology

What is Mycology?

• Mycology is the study of fungi, which are found nearly everywhere on earth, in the air, water, and soil.

Characteristics of Fungi

• Fungi are saprophytic or parasitic eukaryotic microorganisms, distinct from plants and animals.
• They are non-motile, non-photosynthetic, absorb nutrients from their environment, have cell walls, filamentous structures, and produce spores.

Features of Fungi

• Fungal cells are encased within a rigid cell wall, mostly composed of chitin and glucan.
• They are heterotrophic and cannot make their organic food through photosynthesis.
• They have a filamentous branching system of cells.
• Fungi have a life-cycle that begins with germination of spore or resting structure, followed by a period of growth and sporulation.

Importance of Fungi

• Fungi act as decomposers of complex organic materials in the environment.
• They are major causes of plant diseases and also cause diseases of animals and humans.
• Fungi, especially yeast, are essential to many industrial processes involving fermentation, e.g., bread, wine, and beer making.
• They are important in the manufacture of many antibiotics.
• Fungi are important research tools in the study of fundamental biological processes.

Cellular Characteristics of Fungi

• Fungal cells have a nucleus bound by a nuclear membrane.
• They have a cell membrane (plasma lemma) containing glycoproteins, lipids, and ergosterol.
• Fungal cells have a multi-layered rigid cell wall containing chitin (glucose and mannose).
• All fungi produce spores and some produce capsular polysaccharides.

Reproduction in Fungi

• Fungi reproduce asexually and some also sexually.
• The sexual state is called the teleomorph or perfect state, where mating types are (+) and (-) are formed.
• The asexual state is called the anamorph or imperfect state, characterized by conidia.
• Sexual reproduction involves the union of two compatible nuclei.

Other Characteristics of Fungi

• Fungi are not affected by antibiotics.
• Humans are usually accidentally infected by inhalation of spores or inoculation injuries.
• Some yeasts and molds have melanized cell walls, imparting a brown or black pigment.
• Vegetative body may be unicellular (yeast) or composed of multicellular threads called hyphae.