SEMR421
Introduction to
Mycology
GLENNIE ROSE Y. BINONDO, RMT
Table of contents
01 02
GLOSARY OF GENERAL
TERMS CHARACTERISTICS
03 04
TAXONOMY CLINICAL
CLASSIFICATION OF
FUNGI
01 GLOSARY OF TERMS
A. Mycology
A specialized discipline in the field of biology concerned with the
study of fungi, including their taxonomy, environmental impact, and
genetic and biochemical properties.
B. Medical Mycology
The study of fungi that produce pathology or diseases in humans and
animals including their ecology and epidemiology.
C. Diagnostic Mycology
The study of the general characteristics, pathology, pathogenesis and
laboratory tests and methods of medically important fungi that aids in
their identification and treatment.
02
GENERAL
CHARACTERISTICS
GENERAL CHARACTERISTIC
• Stains gram positive in gram staining.
• Eukaryotic organisms
• Lacks chlorophyl absorbs nutrients
• Non-motile
• Complex and rigid cell wall (Contains lipids,
glycoprotein, polysaccharide and complex
CHO such as Chitin, Mannan, Glucan and
Chitosan)
GENERAL CHARACTERISTIC
Growth requirements:
1. Nutritional and Environmental Requirements
• Aerobes
• Heterotrophic: Utilized energy derived
from organic matter.
• Can be classified as:
-Saprophytes (lives on dead or decaying
organic matter)
-Parasites.
GENERAL CHARACTERISTIC
2. Temperature Requirements:
• Most fungi grow between 25-30C
• Dimorphic fungi: The yeast or tissue state is seen in vivo
or when the organism is grown at 37°C
with increased CO2.
The mold phase is seen when the
organism is grown at room temperature
(22° to 25°C) in ambient air conditions.
• Any fungus capable of growing at 37C should be considered
as pathogenic
GENERAL CHARACTERISTIC
2. Incubation Period:
• Cultures are generally maintained for 4 to 6 weeks and
should be examined twice weekly for growth.
• Some yeast grow overnight. (18-24C)
• Saprophyhtes are fast growers.
**Paracoccidioides brasiliensis:
**Histoplasma capsulatum:
Growth Phases:
Growth Phases:
Mold:
Most molds have a fuzzy or woolly
appearance because of the formation of
mycelia. The mycelia are made up of many
long strands of tube-like structures called
hyphae, which are either aerial or
vegetative (Thallus).
Growth Phases:
Yeast:
Reproduce asexually by blastoconidia
formation (budding) and sexually by the
production of ascospores or basidiospores.
Unicellular organisms that are round to oval
and range in size from 2 to 60 µm.
Basic Structures:
1. Hypha (Hyphae; singular
• Microscopic units of fungi which are tube-like filament.
Septate: Divided by cross-walls
Aseptate: Continuous without cross-walls (sparsely septate)
• Hyaline (moniliaceous) hyphae:
• Phaeoid (dematiaceous) hyphae:
Basic Structures:
Basic Structures:
2. Mycelia (Mycelium;singular)
• The mycelia are made up of many long strands of tube-
like structures called hyphae, which are either aerial or
vegetative.
• Thallus: vegetative portion that absorbs water and
nutrients. It grows in or on the substrate. (Culture Media)
• Aerial: extend above the surface of the colony and are
responsible for the fuzzy appearance. It support the
reproductive structures that produce conidia.
03
TAXONOMY
1.Phylum Glomeromycota, order Mucorales
• Lichtheimia (formerly Absidia), Mucor,
Rhizomucor, and Rhizopus.
• Mucorales generally produce profuse, gray
to white, aerial mycelium characterized by
the presence of hyaline, sparsely septate
hyphae.
• Asexual reproduction: sporangiophores.
• Sexual reproduction: zygospores
2. Ascomycota
• Representative organisms include
Microsporum spp., Trichophyton spp., and
Pseudallescheria boydii.
• Fungi associated with the class
Ascomycetes are characterized by the
production of sexual spores known as
ascospores
3. Basidiomycota
• Includes fungi that reproduce sexually
through the formation of basidiospores on a
specialized structure called the basidia.
• Plant pathogen or environmental organism,
includes smuts, rusts, mushrooms, and
Cryptococcus neoformans complex.
4. Fungi Imperfecti
• Phylum Deuteromycota.
• The form division Fungi Imperfecti contains
the largest number of organisms that are
causative agents of mycoses, including
cutaneous, subcutaneous, and systemic
disease.
• Organisms are placed within this group
when no mode of sexual reproduction has
been identified.
3. Basidiomycota
• Includes fungi that reproduce sexually
through the formation of basidiospores on a
specialized structure called the basidia.
• Plant pathogen or environmental organism,
includes smuts, rusts, mushrooms, and
Cryptococcus neoformans complex.
Sexual and Asexual Reproduction
1. Sexual spores: During sexual reproduction,
haploid cells of compatible strains mate
through a process of plasmogamy,
karyogamy, and meiosis.
• Sexual reproduction requires the joining of
two compatible nuclei, followed by meiosis .
A fungus that reproduces sexually is known
as a teleomorph.
Type of Sexual Spores:
1. Ascospores
In the Phylum Ascomycota, following
meiosis, four to eight meiospores form
within an ascus.
Type of Sexual Spores:
2. Basidiospores
In the Phylum Basidiomycota, following
meiosis, four meiospores usually form
on the surface of a specialized
structure, a club-shaped basidium
Type of Sexual Spores:
3. Zygospores
In the Order Mucorales, following
meiosis, a large, thick-walled
zygospore develops. Involves two
identical c cells arising from the same
hyphae,
Type of Sexual Spores:
4. Oospore
Involves fusion of cells from two
separate, non identical hyphae.
Sexual and Asexual Reproduction
2. Imperfect fungi: Fungi that lack sexual
reproduction; they are represented only by an
anamorph, the mitotic or asexual reproductive
state.
• Asexual reproduction is carried out by
specialized fruiting structures known as
conidiogenous cells.
• Types of Conidia formation:
Blastic Conidiogenesis: parent cell enlarges, a septum
forms, and the enlarged portion splits off to form a daughter
cell.
Thallic Conidiogenesis: the septum forms first, and new
growth beyond the Septum becomes the daughter cell
• Size of Conidia
Macroconidia:
-large, usually septate, and sometimes exhibits oval, club, or
spindle shaped appearance.
-may be THICK or THIN walled; and may have a SMOOTH or
SPINY (ECHINULATE) surface.
Microconidia:
-small & unicellular with round, elliptical, or piriform (pear) shape.
Two types are:
• Sessile Microconidia: borne directly on the hyphae
• Pedunculate Microconidia: borne on the end of a short
conidiophore
Type of Asexual Spores:
1. Blastoconidia (blastospores)
Conidial formation through a budding
process (eg, yeasts).
***Pseudohyphae
Type of Asexual Spores:
2. Chlamydospores (chlamydoconidia):
Large, thick-walled, usually spherical conidia
produced from terminal or intercalary hyphal
cells.
Three types of Chlamydoconidia:
• Terminal: forms at the hyphal tip
• Sessile: forms at the hyphal sides
• Intercalary: forms within the hyphal strand
Type of Asexual Spores:
3. Arthroconidia (arthrospores)
Conidia that result from the
fragmentation of hyphal cells.
Type of Asexual Spores:
4. Sporangiospores
Asexual structures characteristic of the
Order Mucorales; they are mitotic
spores produced within an enclosed
sporangium, often supported by one
sporangiophore
01
CLINICAL
CLASSIFICATION
OF MYCOSES
• SUPERFICIAL MYCOSES
• CUTANEOUS MYCOSES
• SUBCUTANEOUS MYCOSES
• OPPORTUNISTIC
• SYSTEMIC
Thanks!
Do you have any questions?
REFERENCES :
• Textbook of Diagnostic Microbiology, Mahon. (6th Edition)
• Bailey Scott's Diagnostic Microbiology. (14th Edition)
• Jawetz, Melnick, & Adelberg’s Medical Microbiology (28th Edition)
