Fungi are eukaryotic organisms that are divided into three main groups: yeasts, molds, and dimorphic fungi. Yeasts are unicellular, oval or rounded organisms that reproduce asexually by budding. Molds are filamentous fungi that form branching hyphae and reproduce sexually through spores. Dimorphic fungi can exist in both yeast and filamentous forms depending on temperature. Candida albicans is a common yeast pathogen of humans that appears gram-positive and oval under the microscope and forms creamy, pasty colonies on Sabouraud's dextrose agar. Aspergillus is a mold that has branching septate hyphae and conidiophores terminating

1. CHRISTINE EFAT TAWFEEK
Mycology Lab

2.  Fungi are a type of eukaryotic organism, and
divide morphologically into three major groups
that are:
1.Yeast: unicellular , oval or rounded.reproduce by a sexual budding, may
form pseudohyphae Ex. Candida spp.
2.Molds (filamentous fungi): branching hyphae ,reproduce by a sexual
sporing. Spores (conidia)may be unicellular or multicellular. Ex. Aspergillus
3. Dimorphic fungi : occurs in both forms. Yeast form in tissues at 37 and
filamentous form in the environment.

3. Yeasts
 Yeast is a single-cell organism, which needs food,
warmth, and moisture to thrive.
 Candida albicans is the commonest yeast causing
disease to humans ( UTI, moniliasis, onychomycosis,
vulvovaginitis, systemic mycosis)

4. Candida albicans
Under Microscope:
 Stained with Gram stain
 Gram positive ,large,oval
yeast cells with budding

6. Candida albicans
 Culture media:
1. Sabauroud ’s dextrose agar:
 is a selective medium primarily used for the isolation
of molds and yeasts .
Ingredients: Gms/Liter
 Peptone: 10.0
 Dextrose: 40.0
 Agar: 15.0

7. Candida albicans
 On Sabauroud’s dextrose agar(SDA):
• large , opaque ,Creamy, pasty colonies, smooth
after 24-48 hours at 25-37°C
•Yeast smell (odour)

8. Candida albicans
• 2-Blood Agar:
• White creamy colored
• Foot-like extensions from the margin

10. 2-Mold
 Branching filamentous hyphae.
 Septate or non septate

11. Aspergillus

12. Aspergillus
 Aspergillus species are medically relevant pathogens.
 For humans, a range of diseases such as infection to the external
ear, skin lesions, and ulcers.

13. Aspergillus
Diagnosis:
 Under microscope:
Stained with Lactophenol cotton blue.

14. Principle of Lactophenol cotton blue Staining
 Lactophenol cotton blue is used in medical mycology for the examination of fungal
cell structure, by preparing a wet mount.It is used for the preparation of
microscopic slides of fungi for examination. Fungal elements are stained
stained intensely blue
 It is composed of the following components :
 1-methyl blue(is a histological stain which stains collagen blue in tissue sections
sections & stains the chitin in the fungal cell walls)

 2-lactophenol (is a mixer of four components such as phenol, lactic acid, and
and glycerol in water. Where phenol helps to kill any microorganisms, lactic acid
preserves fungal structures & acts as a mountant.)
 3-glycerol inhibits the cellulolytic activity of the fungus

16. Aspergillus
1.Conidiophore: terminating in apical vesicle
and in the opposite end, a basal foot cell inserted
into the supporting hyphae.
2.Vesicle:covered partially or completely
by flask-shaped phiallides (uniseriate)
or an intervening cells called metula
3.Phiallides: columnar heads, produce
chains of round,Rough conidia (spores) about(2-5micrometer in diameter).
4-Conidia: Non motile
5- Hyphae: Septate
Vesicle+phiallides+metula(if present)+conidia
= conidial head

18. Aspergillus
 Culture:
On Sabauroud’s dextrose agar (SDA)