1. Fungi

2. Fungi
The Kingdom Fungi includes some of the most important organisms, both in terms of their ecological and economic roles
Eukaryotic- contain membrane bound cell
Are Heterotrophs- cannot manufacture their own food
Most are saprotrophic (decompose dead matter). By breaking down dead organic material, they continue the cycle of nutrients through ecosystems.
Many are parasitic (obtain nutrients from living organisms)
Like plants, fungi have rigid cell walls and are therefore non-motile, a feature which separates them from animals
Produce spores

3. Structures of Fungi Fungi occur in two basic growth forms Yeast
Unicellular fungi
Reproduce by budding
Mold (Filamentous fungi)
Multicellular filamentous, “fluffy” colonies consisting of branching tubular structures called hyphae
Collection of intertwined hyphae called mycelium
Vegetative hyphae act like roots, penetrating the supporting medium and absorbing nutrients
Aerial hyphae project above the surface of the mycelium and bear the reproductive structures of the mold (often spread through the air)

4. Draw and label these structures

5. Fungal Habitats
Fungi can be found in soil, on plants, trees, and other vegetation, and on our skin, mucous membranes, and intestinal tracts
Some have distinctive ecologic and geographical niches.

6. Classification of Fungi
A. Geographic grouping
Classification by geographic distribution. Certain fungal diseases are considered endemic to particular areas
Histoplasmosis - Central Mississippi Valley and Ohio Valley fever
Coccidioidomycosis - San Joaquin Valley fever
B. Epidemiologic grouping
Concerned with how fungal disease is transmitted.
Few are contagious - i.e. ringworm of the scalp. Some are inhaled, others must be directly introduced into deeper tissue such as by a puncture from a thorn.
Most mycoses are dependent on the susceptibility of the individual host.
C. Taxonomy grouping
Scientific grouping according to morphologic and cultural characteristics; varies somewhat, depending on author.

7. Fungal Diseases
Because fungi are more chemically and genetically similar to animals than other organisms, this makes fungal diseases very difficult to treat.
Are often caused by fungi that are common in the environment
Often difficult to diagnose because they may mimic bacterial infections.
Leads to inappropriate treatment with antibiotics, prolonged illness, and delays in diagnosis & initiation of appropriate therapy

8. Fungal Diseases In 1991, an estimated 1.5 million fungi on the Earth
More recent estimates (2011)based on high-throughput sequencing methods suggest that as many as 5.1 million fungal species exist
~300 are known to cause disease in humans
humans are relatively resistant
fungi are relatively nonpathogenic
fungi are the most common plant pathogens

9. Fungi as infectious agents
Mycosis- (Mycoses) disease process caused by fungi
spread generally from the environment to people (or animals) with limited person-to- person spread.
Skin and lungs are prominent entry site for many fungi
Patients with impaired cell-mediated immunity (e.g. AIDS, organ transplant) at heightened risk for severe disease.

10. Fungi as infectious agents
Types of fungal infections based on virulence and level of involvement of the disease
Superficial: Outer skin layer - no immune response
caused mostly by yeasts (Dandruff)
Cutenous: Epidermal layers - evoke immune response
Tinea (Ringworm, Athlete’s foot, jock itch) caused by Dermatophytes
Subcutenous: Chronic infection of subdermal tissues, may require surgical intervention

11. Fungi as infectious agents
Types of fungal infections based on virulence and level of involvement of the disease
Systemic: Mostly originating in the lung
Opportunistic: In immunocompromised conditions, (AIDS; altered mucosal flora due to antibiotics):
mostly Candidiasis and Aspergillosis (often cause of epidemic death in birds)

12. Fungi as infectious agents
Fungal pathogens can be classified in 2 categories
Primary (true) pathogens
Have virulence factors that allow them to invade & grow in a healthy host
Opportunistic pathogens
Weak virulence; causes disease in only weakened or compromised hosts