Introduction to Mycology

Mycology

• Mycology is the study of fungi, including yeasts and molds.
• Fungi's genetic and biochemical properties are studied.
• Fungi's taxonomy and uses for humans (tinder, medicine, food like beer, wine, cheese, mushrooms, and entheogens) are examined.
• Fungi's dangers, like poisoning and infection, are important to understand.

Fungi and Their Roles

• Many fungi produce toxins, antibiotics, and other secondary metabolites (important for their metabolic processes but not essential to survival, e.g., antibiotics and pigments).
• Fungi are vital for life on Earth, serving as symbionts (e.g., mycorrhizae, insect symbionts, and lichens).
• Fungi break down complex organic biomolecules, notably lignin (a component of wood) and pollutants (like xenobiotics, petroleum, polycyclic aromatic hydrocarbons).
• Fungi play a key role in the global carbon cycle by decomposing these materials.

Traditional and Pathogenic Fungi

• Fungi and other organisms (oomycetes and myxomycetes - slime molds) are traditionally recognized as part of the fungi study.
• Fungi are economically and socially important for causing diseases in animals (e.g., histoplasmosis) and plants (e.g., Dutch elm disease, rice blast).
• Some fungi cause diseases in humans and other organisms.
• Medical mycology focuses on the study of pathogenic fungi.
• Actinomycetes, a large group of prokaryotic organisms, are similar to fungi morphologically but are bacteria.
  • Actinomycetes appear as branched or unbranched filaments of cells (hyphae, mycelia).
  • They are bacteria, not fungi.

Structure of Fungi

• The main body of most fungi is composed of branching, usually colorless threads called hyphae.
• Each fungus has a vast number of intertwining hyphae, forming a tangled web called the mycelium.

Fruiting Bodies

• Fruiting bodies (like mushrooms) are thick collections of hyphae.
• These bodies are various sizes, ranging from small to large and noticeable.
• They typically form at the surface of the food source to release spores via wind, water, or animals.

Pathogenic Fungi (Candida)

• Candida species are important human pathogens, known for opportunistic infections in immunocompromised hosts (e.g., transplant patients, AIDS sufferers, cancer patients).
• Candida infections can be challenging to treat and are often serious, sometimes leading to death (30-40% mortality rate for systemic infections).

Pathogenic Fungi (Aspergillus)

• Aspergillus spores are common in the environment, and humans are exposed regularly.
• Aspergillus fumigatus and Aspergillus flavus are common pathogenic species.
• Aspergillus flavus produces aflatoxin, a toxin and carcinogen that can contaminate foods like nuts.
• Aspergillus fumigatus and Aspergillus clavatus can cause allergic diseases.
• Aspergillus species cause disease on grains (especially maize) and produce mycotoxins (like aflatoxin).
• Aspergillosis is a group of diseases caused by Aspergillus.
• Symptoms include fever, cough, chest pain, or breathlessness.
  • Susceptibility to aspergillosis is mostly in patients with weakened immune systems and/or pre-existing lung conditions.

Pathogenic Fungi (Cryptococcus)

• Cryptococcus neoformans can cause severe meningitis and meningoencephalitis in HIV-positive patients and AIDS patients.
• Most Cryptococcus species live in soil and do not cause human disease.

Pathogenic Fungi (Histoplasma)

• Histoplasma capsulatum causes histoplasmosis, a disease primarily affecting the lungs in humans, dogs, and cats.
• Histoplasma is prevalent in the Americas, India, and Southeast Asia.
• Infection typically occurs via inhalation of contaminated air.

Pathogenic Fungi (Pneumocystis)

• Pneumocystis jirovecii (or Pneumocystis carinii) causes pneumonia in immunocompromised people (e.g., premature children, the elderly, and AIDS patients).

Explore the fascinating world of fungi in this quiz on mycology. Learn about their genetic, biochemical properties, and importance in various fields such as medicine and food production. Understand the symbiotic relationships they form and their crucial role in the carbon cycle.