Understanding Fungi: Structure, Function, and Infections

Posted on Nov 21, 2024 in Biology

Mushrooms

Characteristics

Fungi are eukaryotic cells without chlorophyll and chloroplasts. They are heterotrophic organisms, forming their own kingdom. Fungi can be microscopic or macroscopic and are found in various environments, including soil, water, plant and animal remains, and living organisms as parasites.

Structure

Fungi have two main structural types:

  • Levuriforme (Yeast): Unicellular.
  • Mycelial: Multicellular.

Yeast

Yeasts are unicellular organisms with typical eukaryotic organelles. They often have elongated cells, plasma membrane invaginations, and sometimes a cell wall.

Mushroom Spawn

Mushroom spawn consists of elongated filaments called hyphae. These structures have a cell wall, and some hyphae lack septa (non-septate hyphae).

Physiology

Nutrition

Fungi are heterotrophs, obtaining nutrients from organic matter in their environment or other living organisms. They can be saprophytes, feeding on decaying organic matter, or parasites, feeding on living organisms. Digestion varies:

  • Unicellular Fungi: Internal digestion through lysosomes.
  • Multicellular Fungi: External digestion by releasing enzymes and absorbing nutrients.

In the absence of oxygen, some fungi perform fermentation, producing alcohol from carbohydrates.

Reproduction

Fungi reproduce through spores, which can be sexual or asexual. Asexual reproduction occurs through mitotic divisions, producing identical offspring. Sexual reproduction involves meiosis, producing haploid spores that develop into gametes. These gametes fuse to form a diploid zygote.

Mycoses

Mycoses are infectious diseases caused by fungi, often affecting individuals with weakened immune systems.

Candidiasis

Candidiasis is caused by Candida species, affecting skin and mucous membranes. Candida albicans is a common species that can infect the oral cavity, digestive tract, and vagina.

Types of Candidiasis

  1. Thrush: White patches on the oral mucosa, common in infants and the elderly.
  2. Onychomycosis: Nail infection causing redness and pain.
  3. Vaginal Candidiasis: Itching and whitish discharge, common in pregnant women or those on antibiotics.
  4. Intertriginous Candidiasis: Affects skin folds.

Tinea

Tinea refers to dermatological fungal infections affecting keratin-rich tissues.

Types of Tinea

  1. Athlete’s Foot: Affects the spaces between toes, causing cracks and vesicles. Spread through contaminated water. Prevention includes using flip-flops.
  2. Nail Tinea: Thickening of the nail, often accompanying athlete’s foot.
  3. Scalp Tinea: Common in children, causing hair loss and skin peeling. Treated with antifungal creams.