Fungi Explained: Biology, Reproduction, Key Types, Food & Health Effects
Fungal Characteristics
Fungi are eukaryotic organisms classified within the Kingdom Fungi, encompassing yeasts, molds, and mushrooms. While once grouped with plants, fungi possess unique characteristics that led to their classification in a distinct kingdom. The primary distinctions from plants are their heterotrophic nature and cell walls not constructed from cellulose.
Fungal Reproduction
Sexual Reproduction in Fungi
Fungal sexual reproduction relies on the compatibility between hyphae, either from the same individual or a genetically compatible nearby individual of the same species. This compatibility, crucial for crossbreeding, is governed by genetic and chemical factors that influence the proximity to a suitable hypha.
Asexual Reproduction in Fungi
Asexual reproduction is also prevalent in fungi. Many species exhibit at least one vegetative or asexual reproductive event during their life cycle. The primary goal of asexual reproduction in fungi is to expand the fungal mycelium or colonize a specific site or substrate, utilizing existing genes for survival.
Major Fungal Divisions
Ascomycota: Sac Fungi
The Ascomycota phylum is the largest division within the Kingdom Fungi, encompassing a vast number of described species. It notably includes many pathogenic species affecting both animals and plants. This phylum includes yeasts and, due to its mycelial morphology, many species of filamentous fungi. Their hyphae often feature divisions (septa). Ascomycetes may or may not form fruiting bodies, and their characteristic spores, called ascospores, are typically flattened and grouped within sac-like structures known as asci.
Basidiomycota: Club Fungi
Basidiomycota is the second-largest fungal division, currently comprising approximately 32,000 described species. The morphology within this phylum is highly variable; many organisms initially classified elsewhere in the Kingdom Fungi have been reclassified here thanks to genomic studies. Characteristically, this group forms exospores within a fruiting body called a basidium, commonly known as a mushroom.
Fungi in Food: Beneficial or Harmful?
Are fungi in food beneficial or harmful? Generally, the impact depends on both the food item and the specific fungal species involved.
Some molds found in food can produce mycotoxins (poisonous fungal metabolites), which are primarily found in cereal crops and nuts.
Conversely, other fungi are intentionally used in food production, such as in certain types of cheese where they grow on the surface or internally. For example, in veined blue cheeses like Roquefort or Gorgonzola, specific fungal spores are introduced.
Mycotoxins: A Closer Look
Mycotoxins: These are toxic metabolites produced by molds in food. Ingesting contaminated food with sufficient quantities of these substances can cause intoxication in both humans and animals.
Fungal Diseases (Mycoses)
There are several types of skin mycoses, classified by the affected area and the causative fungus:
- Nail fungus
- Candidiasis
- Pityriasis versicolor
- Athlete’s foot
- Inguinal ringworm
- Tinea