Fungi Overview and Classification

Characteristics of Fungi

• Contain nucleus, vacuoles, and mitochondria
• Spore-bearing and can reproduce sexually or asexually
• Cell walls are made of polysaccharides, cellulose, and/or chitin
• Saprophytic and play a crucial role in decomposition
• Over 100,000 known species, but only a few are clinically important

Classification of Fungi

• Divided into two groups: filamentous fungi (moulds) and yeast
• Filamentous fungi have hyphae that extend through transverse divisions, forming a mycelium
• Yeast are single-celled organisms that reproduce by division or budding

Filamentous Fungi

• Examples include Aspergillus, Penicillium, and Trichophyton
• Composed of surface mycelium, aerial hyphae, and cells with many nuclei
• Conidia (asexual spores) are found at the end of hyphal branches and are easily dispersed through the air
• Often contaminate laboratories and can cause allergies

Life Cycle of Filamentous Fungi

• Involves conidiophore, germination, conidia, aerial hyphae, subsurface, and hyphae

Characteristics of Colonies

• Appear dusty on agar plates
• Often brightly colored
• Some species produce sexual spores that are resistant to drying, heating, and freezing
• Can produce fruiting bodies and mushrooms that produce sexual spores

Yeast

• Examples include Candida, Saccharomyces, and Cryptococcus
• Unicellular and grow by budding or fission
• Some species, like Candida albicans, can form a filamentous phase involved in pathogenicity
• Dimorphic fungi can switch between mycelial and yeast forms depending on temperature

Importance of Fungi

Benefits

• Used in food production, nutrient cycles, antibiotic production, fermentation, pest control, and molecular biology

Hazards

• Can cause infections, produce toxins, spoil food, cause decay, and act as plant pathogens

Fungi in Food

• Mushrooms are a type of fruiting body produced by filamentous fungi
• Quorn is a fungal protein used as a vegetarian meat substitute
• Yeast tablets are a dietary supplement rich in protein and riboflavin
• Moulds are used to ripen cheeses

Antibiotic Production

• Most antibiotics are produced by filamentous fungi, especially Streptomyces spp.
• Species of Aspergillus and Penicillium are also used in antibiotic production
• Other antibiotics produced by fungi include fumigillin, griseofulvin, and cephalosporins

Fungi in Biotechnology

• Used to produce chemicals, pharmaceuticals, citric acid, kojic acid, itaconic acid, steroids, glycerol, ethanol, and enzymes like amylases and penicillin acylase

Learn about the characteristics and classification of fungi, including their cellular structure, reproduction methods, and types such as moulds and yeast.