1. General Properties of Fungi Sevtap Arikan, MD

2. FUNGUS
Widely distributed in nature (air, water, soil, decaying organic debris)
~400,000 types
Eukaryotic, highly developed cellular structure
Facultatively anaerobic/strict aerobic
Chemotropic, nutrition: by absorption
Nonphotosynthetic

3. Terminology Mykos: Fungus Mycoses: A disease caused by a fungus
Mycology: Study of fungi

4. Major Developments in Mycology
Increase in number of immunocompromised patients
Newly developed antifungal drugs
Antifungal susceptibility testing
Resistance to antifungal drugs

5. Fungi- Morphological Classification
Yeast
Mould
Dimorphic

6. YEAST
Unicellular
Micr.: Oval to round (Dia: 3-15 µm) Reproduce by budding Bud=Blastospore
Pseudohyphae
Macr.: Pasty colonies (resemble bacteria)

7. MOULD Multicellular Micr.: Hypha(e) (dia: 2-10 µm) Spores
Macr.: Surface texture: Cottony/ wooly/ velvety/ granular...
Pigmentation: observed from the reverse

8. Mould-Definitions
Hypha
Mycelium: a. Vegetative
b. Aerial

9. Classification of Hyphae
BASED ON:
A. Existence of septa
Septate
Nonseptate
B. Shape and Morphology
Racquet Spiral
Nodular Root-like (rhizoid)
Pectinate Chandler

10. DIMORPHIC
Capable of growing in mould or yeast form under different environmental conditions (temperature, CO2, nutrients)
Thermal dimorphism (a group of pathogenic fungi)

11. Subcellular Structure of Fungi
Capsule (present only in some fungi)
Cell wall
Cell membrane
Cytoplasm
Nucleus, nuclear membrane, nucleolus, ER, mitochondria, vacuoles

12. CAPSULE Structure: Polysaccharide
Functions: -Antiphagocytic -Virulence factor
Exist only in some fungi
Cryptococcus neoformans (encapsulated yeast)

13. CELL WALL Antigenic in nature Structure: Multilayered
a. polysaccharides (~90%): hexose and hexosamine polymers
b. proteins and glycoproteins (~10%)
Functions:
Provides shape, rigidity, strength and protection from osmotic shock

14. Major polysaccharides of fungal cell wall
POLYMER MONOMER
Chitin N-acetyl glucosamine
Chitosan D-Glucosamine
Cellulose D-Glucose
-Glucan D-Glucose
-Glucan D-Glucose
Mannan D-Mannose
The type and amount of the polysaccharide vary from one fungal species to other.

15. CELLULAR MEMBRANE Structure: Bilayered Phospholipids
Sterols (ergosterol, zymosterol)
Functions:
a. Protects cytoplasm
b. regulates the intake and secretion of solutes
c. facilitates capsule and cell wall synthesis

16. FUNGAL SPORES Spores function in reproduction of fungi.
1. Sexual reproduction --Sexual spores
2. Asexual reproduction--Asexual spores
3. Parasexual reproduction--Genetic exchange

17. SEXUAL SPORES
1. Zygospore
2. Ascospore
3. Basidiospore
4. Oospore

18. ASEXUAL SPORES 1. Arthrospore 2. Blastospore 3. Chlamydospore
4. Macroconidium
5. Microconidium
6. Sporangiospore

19. Fungi-Taxonomic classification
Depends primarily on the type of sexual spore
Phylum -mycota
Class -mycetes
Order -ales
Family -ceae
Genus
Species

20. Fungi-Taxonomic classification
SEXUAL SPORE CLASS
Zygospore Zygomycetes
Basidiospore Basidiomycetes
Ascospore Ascomycetes
None/Unknown---- Deuteromycetes
(“Fungi Imperfecti”)

21. MYCOSES Superficial (Hair, skin, nail, cornea) Subcutaneous
True systemic (endemic)
Opportunistic

22. LABORATORY DIAGNOSIS OF MYCOSES
Direct microscopic examination
Gram, potassium hydroxide (KOH), calcofluor white, India ink
Culture
Sabouraud dextrose agar
Mycobiotic agar
Serology