Mycology is the study of fungi, which is branch of biology. Approximately 80,000 species of fungi have been described. The main characteristics of fungi. They are an important component in the energy cycle. They are eukaryotic organisms that do not contain chlorophyll, with cell wall containing chitin .
absorb
Extra enzymeInsoluble polymer
Fungi
Soluble organic materials
They have no organic level differentiation. The cell membrane contains sterols. Moisture is necessary for the growth of molds and yeasts, they prefer moderate temp. All fungi need a protein source and carbohydrate source. Fungi are able to tolerate a wide rang of PH, many of them can grow in medium that have a PH 2-10, although they prefer a neutral PH.
They may be unicellular or multicellular. Yeasts are generally unicellular and produce circular restricted pasty or mucoid colonies. Molds are multicelled filamentous forms of fungi consisting of thread like filaments termed hyphae.
septate hyphae
hypha
aseptate
Many of the fungal pathogen are dimorphic or diphasic, with a yeast (Y) and a mycelial (M) phase.
11. Many fungi are responsible for much of the disintegration of organic matter and they affect us directly by destroying food, fabrics, leathers and other consumer. Other fungi are beneficial which are the basis of a number of industrial processes involving: Fermentation such as making of bread. alcoholic fermentation. preparation of certain cheeses. Production of many organic acids. Responsible for the manufacture of a number of antibiotic drugs as penicillin which is produced by penicillium
Some cause diseases in plants, animal and harm man more directly. There are four type of mycotic diseases: Hypersensitivity. Mycotoxicoses. Mycetismus. Infection: pathogenic fungi do not produce toxins but they show physiologic modifications during a parasitic infection
Classification of fungi: There are four (4) important classes of medically important fungi class Zygomycetes (lower fungi). class Ascomycetes Telomorphic or class Basidiomycetes perfect fungi. class Deutromycetes anamorphic or imperfect fungi Fungi in class Zygomycetes have wide mycelium.
Nuclei
Reproduction of fungi Fungi reproduce by spores either sexually or asexually. The spore is a resistant unit of fungi.
Sexual reproduction involve three (3) processes Plasmogamy i.e. fusion of protoplasm of (2) sex cells to form a pigmass. Karyogamy i.e. fusion of (2) nuclei to form one mass. Meosis i.e. reduction division.
Sexual reproduction in Zygomycetes Plasmogamy Karyogamy Meosis + - Exp: Rhizopus, Mucor 4 Zygospores.
Resting
Sexual reproduction in Ascomycetes
Resting
Plasmogamy Karyogamy Meosis
4 Ascospores mitosis 8 Ascospores (inside ascus)
Sexual reproduction in Basidiomycetes
resting
EX.P: Mushroom
Basidium
Basidiospores
plasmogamy Karyogamy Meosis
4 basidiospores (exogenous)
Deutromycetes have no sexual reproduction only asexual form Asexual spores The morphology, arrangement and mode of derivation of spores serve as important criteria by which genus and species identification can be made Sporangiospores:
Sporangiospores
Sporangium Sporangiophores
2. Arthrospores (arthroconidia): They formed due to fragmentation of the mycelium EX.P: Geotrichum, TrichosporonEX. P: Rhizopus
3. Blastospores (Blastoconidia): Produce by budding and separation from the parent cell
EX.P: Candida4. Chlamydospores (chlamydoconidia):
Terminal
Intercalary
+
5. Conidia: Usually produced terminally or laterally on hyphae or special structure, conidiophores, and are borne externally as a single cell. conidia either unicellular (microconidia) or multicellular (macroconidia) EX.P: penicillium, Dermatophytes.
unicellular
multicellular