Structure and morphology
of fungi
Mrs. Dalia kamal Eldien
Msc in Microbiology
Lecture NO (1)
Objective
Definition of mycology
Beneficial Effects of Fungi
Harmful Effects of Fungi
General properties of fungi
Morphology of fungi
Introduction
 The term "mycology" is derived from Greek word "mykes"
meaning mushroom.
 The mycology is the study of fungi
 The medical mycology is a branches that deal with the
study of pathogenic fungi to man and animal, the fungal
infections now a day are in increasing rate
Beneficial Effects of Fungi
1-Decomposition :
lower fungi produce enzyme break down the organic dead materials
2-Biosynthetic factories:
The fermentation property is used for the industrial production of
alcohols, fats, citric and gluconic acids.
3-Important sources of antibiotics:
such as Penicillin(Penicillium chrysogenum).
Cephalosporin(Cephalosporium acremonium)
5- Model organisms for biochemical and genetic studies
e.g: Neurospora crassa, Saccharomyces cerviciae is extensively
used in recombinant DNA technology.
6-Some fungi are eatable e.g Mushrooms
7-Yeasts used in bakery, yogurt, cake……..
Mushrooms
Cake& cheese (yeast)
Harmful Effects of Fungi
1. Destruction of food, lumber, paper, and cloth.
2. Food poisoning, toxins produced by poisonous mushrooms
(Mycetism and Mycotoxicosis).
3. Plant diseases.
4. Damage of agriculture produce such as vegetables and cereals
in the godown.
5. Damage the products such as magnetic disks, glass lenses,
marble statues, bones and wax.
6. Animal and human diseases.
Wood decaying fungus
Destruction of food by fungi
General properties of fungi
 They are eukaryotic; cells contain membrane bound cell
organelles including nuclei, mitochondria, Golgi apparatus,
endoplasmic reticulum, lysosomes etc.
 They reproduce by mitosis.
 Have Ergosterols in their membranes(in contrast to
cholesterol found in mammalian cells) and possesses 80S
ribosome's.
 Have a rigid cell wall made of chitin and they are non-motile,
this feature that separates them from animals.
 Fungi are osmiotrophic; they obtain their nutrients by
absorption
 Are chemoheterotrophs (require organic compounds for both
carbon and energy sources) and fungi lack chlorophyll and
are therefore not autotrophic.
 All fungi require water and oxygen and there are no obligate
anaerobes.
 Typically reproduce asexually and/or sexually .
 Food storage is generally in the form of lipids and glycogen.
Eukaryotic cell
Reproduction in fungi
 Fungi reproduce asexually and sexually
 Asexual reproduction is the commonest mode in most fungi
 Asexual spores are produced following mitosis where as
sexual spores are produced following meiosis.
Morphology of fungi
Fungi exist in two fundamental forms;
 The filamentous (hyphae)
 Single celled budding forms (yeast).
Filamentous fungi
 The main structure element are cylindrical tube like
structures refer to as hypha(e)
 Amass of hyphae is known as mycelium.
 The hyphae may be branched or unbranched.
 They may be septate or aseptate (coenocytic), hyphae
usually have cross walls that divide them into numerous
cells, these cross walls, called septa have small pores
through which cytoplasm is continuous throughout the
hyphae.
Septate hyphae
Non-Septate Hyphae (Coenocytic)
Mycelium are divided in to 3 parts
1. Vegetative mycelium are those that penetrates the
surface of the medium or substrate and absorbs nutrients.
2. Aerial mycelium are those that grow above the agar
surface
3. Fertile mycelium are aerial hyphae that bear
reproductive structures
• Example : Moulds, Dermatophytes
Yeasts
 Yeasts are unicellular cells with different shape and size
round, oval or elongated.
 They reproduce by budding, which result in blastospore
 In some cases, as the cells buds the buds fail to detach and
elongate thus forming a chain of elongated hyphae like
filament called pseudohyphae, this property is seen in
Candia albicans.
 True yeasts such as Saccharomyces cerviciae don't produce
pseudohyphae.
 Some yeast are produce polysaccharide capsule
Budding in yeast
Yeast under light microscope
Dimorphic fungi
 Some species of fungi have the ability to shift from the
yeast form to the filamentous (mold) form and vice versa.
These fungi are dimorphic.
 They can exist in filamentous or yeast form depending on
the condition of growth, mainly the temperature
26 C = filamentous form
37 C= yeast form
 Example: Histoplasma Capsulatum