Fungi

What is the study of fungi called?

Mycology.

What is a yeast?

A unicellular fungus that reproduces by budding or fission.

What are hyphae?

Thread-like filaments that make up filamentous fungi.

What is ergosterol?

A cholesterol-like molecule in fungal cell membranes, essential for survival.

What are the main components of the fungal cell wall?

Beta glucan, mannans, and chitin.

Why is ergosterol clinically important?

Antifungal drugs target ergosterol synthesis/function, harming fungi without affecting human cells.

What is the difference between yeast and filamentous fungi?

Yeast = unicellular, reproduces by budding/fission. Filamentous = multicellular, with hyphae forming a mycelium.

What is the optimal growth temperature for most fungi, and why is this significant?

20-25C; most live outside the body, but some adapt to 37°C, making them pathogenic.

Which diagnostic methods are used for yeasts vs filamentous fungi?

Yeasts = selective/enriched culture, biochemical tests, MALDI-TOF.

Filamentous = agar culture, microscopy (KOH stain), antigen/molecular tests.

How does the fungal cell wall differ from mammalian cells, and why is this useful clinically?

Fungal wall has B-glucan, mannans, and chitin; absent in humans. This makes it a drug target for antifungals.

Classify these infections:

• Oral thrush

• Nail infection

• Pulmonary aspergillosis

• Oral thrush = superficial; Nail infection = subcutaneous; Pulmonary aspergillosis
  = systemic.

Why are systemic fungal infections more common in immunocompromised patients?

Their weakened immune systems can't control fungi that normally wouldn't cause disease.