Kingdom Fungi
1
Characteristics
2
The Characteristics of Fungi
Fungi are NOT
plants
 Nonphotosynthetic
 Eukaryotes
 Nonmotile
 Most are saprobes
(live on dead
organisms)

3
The Characteristics of Fungi
Absorptive heterotrophs
(digest food first & then
absorb it into their bodies
 Release digestive enzymes to
break down organic material
or their host
 Store food energy as
glycogen

BREAD MOLD
4
The Characteristics of Fungi
Important decomposers
& recyclers of nutrients
in the environment
 Most are multicellular,
except unicellular yeast
 Lack true roots, stems
or leaves

MULTICELLULAR
MUSHROOM
UNICELLULAR YEAST
5
The Characteristics of Fungi
Cell walls are made of chitin
(complex polysaccharide)
 Body is called the Thallus
 Grow as microscopic tubes
or filaments called hyphae

6
The Characteristics of Fungi
Some fungi are internal or
external parasites
 A few fungi act like predators &
capture prey like roundworms

Predaceous
Fungi feeding on
a Nematode
(roundworm)
7
The Characteristics of Fungi

Some are edible, while others
are poisonous
EDIBLE
POISONOUS
8
The Characteristics of Fungi
Produce both
sexual and
asexual spores
 Classified by
their sexual
reproductive
structures

Spores come
in various
shapes
9
The Characteristics of Fungi
Grow best in warm, moist
environments
 Mycology is the study of fungi
 Mycologists study fungi
 A fungicide is a chemical used to
kill fungi

Fungicide kills
leaf fungus
10
The Characteristics of Fungi
Fungi include
puffballs, yeasts,
mushrooms,
toadstools, rusts,
smuts, ringworm, and
molds
 The antibiotic
penicillin is made by
the Penicillium mold

Penicillium mold
Puffball
11
Vegetative Structures
NON-REPRODUCTIVE
12
Hyphae
Tubular shape
 ONE continuous
cell
 Filled with
cytoplasm & nuclei
 Multinucleate
 Hard cell wall of
chitin also in insect
exoskeletons

13
Hyphae


Stolons –
horizontal hyphae
that connect
groups of hyphae
to each other
Rhizoids – rootlike
parts of hyphae
that anchor the
fungus
STOLON
RHIZOIDS
14
Hyphae



Cross-walls called
SEPTA may form
compartments
Septa have pores
for movement of
cytoplasm
Form network called
mycelia that run
through the thallus
(body)
15
Absorptive Heterotroph




Fungi get carbon from organic sources
Tips of Hyphae release enzymes
Enzymatic breakdown of substrate
Products diffuse back into hyphae
Nucleus “directs” the digestive
process
Digested material is then used by the hypha
Modifications of hyphae

Fungi may be classified based on
cell division (with or without
cytokinesis)
 Aseptate or coenocytic (without
septa)
 Septate (with septa)
NO CROSS
WALLS
CROSS
WALLS
17
Modifications of hyphae
HAUSTORIA – parasitic hyphae
on plants & animals
Septate Hyphae Coenocytic Hyphae
18
Hyphal growth
Hyphae grow from their tips
 Mycelium is an extensive, feeding
web of hyphae
 Mycelia are the ecologically active
bodies of fungi

This wall is rigid
Only the tip wall is plastic and stretches
19
REPRODUCTIVE STRUCTURES
ASEXUAL & SEXUAL SPORES
20
REPRODUCTION
Most fungi reproduce Asexually
and Sexually by spores
 ASEXUAL reproduction is most
common method & produces
genetically identical organisms
 Fungi reproduce SEXUALLY when
conditions are poor & nutrients
scarce

21
Spores
Spores are an adaptation to life on
land
 Ensure that the species will
disperse to new locations
 Each spore contains a reproductive
cell that forms a new organism
 Nonmotile
 Dispersed by wind

22
Sexual Reproduction
23
SEXUAL REPRODUCTION



Used when environmental
conditions are poor (lack
of nutrients, space,
moisture…)
No male or female fungi
Some fungi show
dimorphism

May grow as
MYCELIA or a
YEAST –LIKE state
(Filament at 25oC &
Round at 37oC)
Dimorphic Fungi
24
SEXUAL REPRODUCTION



Haploid 1n hyphae from 2 mating types
(+ and -) FUSE (Fertilization)
Forms a hyphae with 2 nuclei that
becomes a ZYGOTE
The zygote divides to make a SPORE
+
SPORE FORMS
25
ASexual Reproduction
26
Three types of Asexual Reproduction



Fragmentation – part of the mycelium
becomes separated & begins a life of
its own
Budding – a small cell forms & gets
pinched off as it grows to full size
 Used by yeasts
Asexual spores – production of spores
by a single mycelium
27
Reproduce by spores

Spores may be Formed:
Directly on hyphae
 Inside sporangia
 On Fruiting bodies

Penicillium
hyphae
Amanita fruiting body
Pilobolus sporangia
ASEXUAL REPRODUCTION
Fruiting Bodies are modified hyphae
that make asexual spores
 An upright stalk called the
Sporangiosphore supports the spore
case or Sporangium

29
ASEXUAL REPRODUCTION

Types of
Fruiting Bodies:
 Basidia
 Sporangia
 Ascus
Sporangia
Basidia
30
Hyphal growth from spore
Germinating spore
mycelium


Mycelia have a huge surface area
More surface area aids digestion &
absorption of food
31
It’s All About the Spores!

Fungi are classified by their

The reproductive structures are:
REPRODUCTIVE STRUCTURES and
SPORES
BASIDIA - BASIDIOMYCOTA
 SPORANGIA - ZYGOSPORANGIA
 ASCUS - ASCOMYCOTA

32
It’s All About the Spores!

Spores are made of:



Dehydrated cytoplasm
Protective coat
Haploid cell
Wind, animals, water, & insects
spread spores
 Spores germinates when they land
on a moist surface (new hyphae
form)

33
asci
zygosporangia
motile spores
basidia
Classification
& Phylogeny
34
Major Groups of
Fungi
35
Major Groups of Fungi
Within the past
few years, several
groups have been
re-classified into
the protists
 Two of these
groups are the
slime molds and
water molds

Classification by Nutrition

Saprobes
Decomposers
 Molds, mushrooms, etc.


Parasites
Harm host
 Rusts and smuts (attack plants)


Mutualists
Both benefit
 Lichens
 Mycorrhizas

37
Major Groups of Fungi
Basidiomycota – Club Fungi
 Zygomycota – Bread Molds
 Chytridiomycota – Chytrids
 AM Fungi - Mycorrhizas
 Ascomycota – Sac Fungi
 Lichens – Symbiosis (algae & Fungi)

ZYGOmycota
39
Zygomycota






Called the sporangium
fungi
Commonly called molds
Also includes blights
Hyphae have no cross
walls (aseptate)
Grow rapidly
Includes bread mold
Rhizopus stolonifer
Rhizopus on strawberries
Tomato Blight
Zygomycota



Asexual reproductive structure called
sporangium atop sporangiospores make
spores
Rhizoids anchor the mold & release
digestive enzymes & absorb food
Stolons connect the fruiting bodies
Zygomycota



Sexual spores are produced by
conjugation when (+) hyphae and (-)
hyphae fuse
Sexual spores are called ZYGOSPORES
Zygospores can endure harsh
environments until conditions improve
zygospore
Basidiomycota
43
Basidiomycota


Called Club fungi
Includes:
 Mushrooms
 Toadstools
 Bracket & Shelf fungi
 Puffballs
 Stinkhorns
 Rusts and smuts
USES For Basidiomycota


Some are used as
food (mushrooms)
Others damage
crops (rusts &
smuts)
Corn Smut
Portobello Mushrooms
Soybean
Rust
Characteristics of Club Fungi






Seldom reproduce asexually
The visible mushroom is a fruiting body
Basidiocarp (fruiting body) is made of a
stalk called the stipe and a flattened
cap with gills called Basidia underneath
Basidiospores are found on basidia
Annulus is a skirt-like ring around some
stipes
Vegetative structures found below
ground
46
Ascomycota
47
Characteristics
Called Sac fungi
 Includes Cup fungi, morels, truffles,
yeasts, and mildew
 May be plant parasites (Dutch elm
disease and Chestnut blight)
 Reproduce sexually & asexually
 Ascus - sac that makes ascospores in
sexual reproduction
 Specialized hyphae known as Ascocarps
contain the asci

Characteristics
Yeasts reproduce
asexually by budding
(buds break off to
make more yeast
cells)
 Asexual spores called
conidia form on the
tips of special hyphae
called conidiophores

CONIDIA
Conidia Formation
50
Yeasts Budding
Saccharomyces
Uses of Ascomycetes
Truffles and morels are
good examples of edible
ascomycetes
 Penicillium mold makes
the antibiotic penicillin.
 Some ascomycetes also
gives flavor to certain
cheeses.
 Saccharomyces
cerevesiae (yeast) is used
to make bread rise and
to ferment beer & wine.

CHYTRIDIOMYCOTA
53
Chytridiomycota




Called chytrids
Produce motile
spores
Mostly saprobes
and parasites in
aquatic habitats
Biodegrade and
recycle nutrients
Chytrid that attacks Potatoes
MYCORRHIZA
55
Mycorrhizas
Fungus associated with plant roots
 Mutualism between:
 Fungus (nutrient & water uptake for
plant)
 Plant (carbohydrate for fungus)
 Several kinds:
 Zygomycota – hyphae invade root
cells
 Ascomycota & Basidiomycota –
hyphae invade root but don’t
56

Lichens
57
Lichens


Mutualism between:
 Fungus (structure)
 Algae or
cyanobacteria
(provides food)
Form a thallus (body)
 Foliose
 Fruticose
 Crustose
Lichen structure
59
Lichens as biomonitors




Thalli act like sponges
Some species more sensitive than
others to pollutants
Which species are present can
indicate air quality
Most resistant species can also be
analyzed for pollutants
60
Fungal Diseases



Mycosis- fungal infection
 < 100 cause human disease
 Not highly contagious
 Humans acquire from nature
Groups based on degree on tissue involvement
and mode of entry
Cutaneous mycoses-dermatophytes
 Epidermis, hair & nails
 Contagious-direct or indirect contact
 Secrete keratinase that degrades keratin
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4223 – The Fungi
Cutaneous Mycoses




Tinea( worm) capitis –blisters with scaly ring
Ringworm of the scalp
 Spreads circularly forming bald spots
 Spread by contact with fomites , cats and
dogs
Tinea cruris- ringworm of groin
Tinea pedis - athlete's foot
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Systemic Mycoses






Dimorphic fungi
 Yeast form is invasive
Can spread throughout body
Usually caused by fungi in soil
Inhalation of spores
Begins in lungs and spread to rest of
body
Not contagious person to person
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4223 – The Fungi
Introduction



Obligate Parasitic Fungi
(dermatophytes): evolved to attack the
outer surface of humans
Facultative soil fungi: thermal
dimorphic saprobes, adaptations to
human body
Opportunistic saprobes: attack people
with compromised immune systems
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4223 – The Fungi
Introduction
Fungal Infections
 Superficial infections: involve outermost
layers of skin and its appendages [ nails or
hair] ( Dermatophytosis)
 Cutaneous infections: involve deeper layers
of skin causing allergic or inflammatory
response
 Subcutaneous infections: fungi with low
virulence, localized infection, or spread by
mycelial growth
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4223 – The Fungi
Introduction

Systemic infections: caused by true
pathogenic fungi or opportunistic
saprobes
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4223 – The Fungi
Mycoses: diseases cause by
fungi



Superficial
Subcutaneous
Opportunistic
Cutaneous
Systemic
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4223 – The Fungi
The Situation
Frequency
- most common fungal pathogen worldwide
- 4th leading causes of nosocomial infections, 40% mortality
- significant mortality and morbidity in low birth-weight infants
- affects 75% women, 45% experience recurrence
> 10 million visits/year
- classified as a STD by CDC
Immunocompromised
- cancer and HIV-AIDs patientsC
- most commonly manifested in patients with leukemia
or HIV-AIDs infections. Oral candidiasis is often a
clue to acute primary infectionC
Public Concerns
- increasing resistance to drug therapies due to antibiotics and
antifungals
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4223 – The Fungi
FUNGAL DISEASES
Mycosis: Any fungal disease. Tend to be chronic because fungi
grow slowly.
Mycoses are classified into the following categories:
I. Systemic mycoses: Fungal infections deep within the body.
Can affect a number if tissues and organs.

Usually caused by fungi that live in the soil and are inhaled.
Not contagious.

Examples:

Histoplasmosis (Histoplasma capsulatum): Initial
infection in lungs. Later spreads through blood
to most organs.

Coccidiomycosis (Coccidioides immites):
Resembles tuberculosis.
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4223 – The Fungi
Systemic Mycosis: Histoplasmosis
Disseminated Histoplasma capsulatum, lung infection.
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4223 – The Fungi
FUNGAL DISEASES (Continued)
II. Cutaneous mycoses: Fungal infections of the skin, hair, and
nails.



Secrete keratinase, an enzyme that degrades keratin.
Infection is transmitted by direct contact or contact with
infected hair (hair salon) or cells (nail files, shower floors).
Examples:

Ringworm (Tinea capitis and T. corporis)

Athlete’s foot (Tinea pedis)

Jock itch (Tinea cruris)
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4223 – The Fungi
Opportunistic Infection by Candida
albicans in an AIDS Patient
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4223 – The Fungi
Severe nail infection with Trichophyton rubrum in
a 37-year-old male AIDS patient.
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4223 – The Fungi
Disseminated Histoplasma capsulatum, skin infection.
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4223 – The Fungi
Cutaneous Mycosis
Ringworm skin infection: Tinea corporis
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Cutaneous Mycosis
Candida albicans
infection
of the nails.
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4223 – The Fungi
FUNGAL DISEASES (Continued)
III. Subcutaneous mycoses: Fungal infections beneath the
skin.



Caused by saprophytic fungi that live in soil or on vegetation.
Infection occurs by implantation of spores or mycelial
fragments into a skin wound.
Can spread to lymph vessels.
IV. Superficial mycoses: Infections of hair shafts and
superficial epidermal cells. Prevalent in tropical climates.
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4223 – The Fungi
FUNGAL DISEASES (Continued)
Opportunistic mycoses: Caused by organisms that are
generally harmless unless individual has weakened defenses:




AIDS and cancer patients
Individuals treated with broad spectrum
antibiotics
Very old or very young individuals (newborns).
Examples:


Aspergillosis: Inhalation of Aspergillus spores.
Yeast Infections or Candidiasis: Caused mainly
by Candida albicans. Part of normal mouth,
esophagus, and vaginal flora.
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4223 – The Fungi
Cutaneous Infections
Dermatophytic hyphomycetes
 40 species
 Epidermophyton (2 species)
 Microsporum (17 species)
 Trichophyton (24 species)
 50% of dermatophytes human specific
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4223 – The Fungi
Cutaneous Infections
Cause common tinea (ringworm)
 Grow only on humans
 Reservoir not in soil or animals
 Reservoir in carpets and upholstery
for up to two years

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4223 – The Fungi
Cutaneous Infections


Trichophyton
rubrum
Chronic infections
of the toe nails
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Tinea corporis
Subcutaneous mycoses
Subcutaneous infections - over 35
species produce chronic inflammatory
disease of subcutaneous tissues and
lymphatics. e.g. sporotrichosis ulcerated lesions at site of inoculation
followed by multiple nodules - caused
by a dimorphic fungus: Sporotrix
schenckii.
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4223 – The Fungi
Cutaneous Infections

Microsporum canis
 Reservoir in cat
 May move to humans or dogs
 Dies out after one or two personperson transfers
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4223 – The Fungi
Cutaneous Infections

Disease process
 Fungus stimulates epithelial cells of
skin to divide more frequently
 Makes more keratin available to
fungus
 Some species race specific in humans
 Some species body location specific
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4223 – The Fungi
Cutaneous Infections

Candida albicans – candidiasis
 Normal component of gut mycota
 Excessive wetness  overgrowth on
skin
 Vaginal candidiasis common in
pregnant women
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4223 – The Fungi
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4223 – The Fungi
Biology of Candida albicans
Commensal
Pathogen
A thin-walled dimorphic fungus
Morphogenesis
Unicellular yeast (harmeless)
Filamentous (pathogenic)
Principal Cell Wall Polymers
Gluccan
Mannan
Figure 1. Yeast in Oral Scraping
A sample of an oral scraping contains yeast cells and
pseudohyphae
(www.doctorfungus.org)
Strict aerobe, favors moist surfaces
Commensally found in gut, genitals, and lungs
Body Temp 37º C, neutral pH
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Rapid Multiplication & Spread
Diseases by C. albicans
Thrush
Esophagitis
Cutaneous Candidiasis
Genital Yeast Infections
Deep Candidiasis
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Oropharyngeal Thrush
* Pseudomembranous
* Atrophic
* Angular chelitis
Figure 1. Angular chelitis
Symptoms
Risk Factors
HIV
Treatment: topical
antifungals
Figure 2. Oral Thrush, atrophic
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4223 – The Fungi
Figure 3. Oral Thrush, pseudomembranous
Genital Yeast Candidiasis
Symptoms
Risk Factors
- disruption of normal
microbiota
Figure 1. Vaginal Yeast Culture
Treatment
- direct genital administration
- tablets, suppositories, creams
Figure 2. Plasma cell balanitis. A
band-like infiltrate of plasma cells is in
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4223 – The Fungi
Deep Candidiasis
Figure 1. Four forms of invasive candidiasis
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4223 – The Fungi
Pathogenesis
Host Recognition
Adhesins
Enzymes
Hydrolases: Phosphoplipases, Lipases, Proteinases
Morphogenesis
Yeast form to Filamentous hyphae/pseudohyphae
Phenotypic Switching
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Virulence assay of different C. albicans strains using the skin equivalent (AST 2000)
Figure 1. skin equivalent before infection
Figure 2. Infection with pathogenic clinical isolate of C. albicans.
After 48 h the yeast penetrates the skin equivalent and destroys
the tissue
Figure 3. Infection with non-pathogenic C. albicans. This strain is not
able to penetrate into the tissue and thus behaves as avirulent as shown
in the mouse model of systemic infection.
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(Fraunhofer, 2002)
MORPHOGENESIS
Figure 1. Morphogenesis.
Morphogenesis in
C. albicans is a pivotal
virulence factor that allows
rapid multiplication and
subsequent dissemination
in host tissue.
(www.kent.ac.uk)
Figure 2. Morphogenic forms of Candida albicans
http://cbr-rbc.nrc-cnrc.gc.ca/thomaslab/candida/caindex.html
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Subcutaneous Infections
Fungal Activity
 Fungi normally saprobic
 Introduced through wounds
 Adapt to the human animal by changes in
 morphology
 physiology
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4223 – The Fungi
Subcutaneous Infections
Chromoblastosis
 Common among barefoot peoples of the
tropics
 Soil hyphomycete species
 Enters human by thorns or wood slivers
 Fungus grows  host cells respond by
rapid cell division  wart-like growths
on feet or legs
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4223 – The Fungi
Subcutaneous Infections
Mycotic Mycetoma
 Disease of barefoot tropical people
 Entry: wound on foot
 Attacks various tissues
 Stimulates formation of tumor
 Compact fungal colonies form within
tumor
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4223 – The Fungi
Subcutaneous Infections

Skin ruptures and
some colonies
extrude
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Systemic Mycoses
Introduction
 Caused by . . .
 Specialized pathogens
 Dimorphic
 One form outside the host
 Another form inside the host
 Opportunistic saprobes
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Systemic Mycoses
Dimorphic Pathogen Mycoses
 Histoplasmosis
 Histoplasma capsulatum
 Grows on bird droppings, chicken
manure, bat guano
 Conidia inhaled  primary lung
infection  almost always fatal until
recently
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Systemic Mycoses

Histoplasma
capsulatum
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Systemic Mycoses
Coddidioidomycosis
 Coccidioides immitis
 Dry, saline soils
 Endemic to SW deserts of North
America
 Valley fever
 Until recently – almost always fatal
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Systemic Mycoses


Infection, disease process, and clinical
symptoms similar to histoplasmosis
Can be effectively treated with
fluconazole
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Opportunistic Pathogens/Disease
General
 Pathogens all grow well at 37C
 None cause disease in well individuals
 Require breakdown in resistance system
 Complication of diabetes, AIDS,
advanced cancer, sequel to steroid or
antibiotic treatments
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Opportunistic Pathogens/Disease
Zygomycosis
 Species of Zygomycota
 Rhizopus, Mucor, Rhizomucor
 Rhinocerebral mycosis
 Spores enter through sinuses
 Grows rapidly outward to the eyes and
inward towards the brain
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Opportunistic Pathogens/Disease
Aspergillosis
 Aspergillus sp.
 Bronchiopulmonary aspergillosis
 Mucus within the bronchi  severe
allergic reaction
 Aspergilloma
 Forms a mycelia ball in lung cavity
formed from earlier TB
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Opportunistic Pathogens/Disease
Surgical intervention often required
Invasive aspergillosis
 Severely debilitated
 Immunosuppressed (AIDS)
Almost always fatal until recently



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AIDS and Mycoses





Aspergillosis
Candidiases (Candidiasis seen in 2/3 of
AIDS patients
Cryptococcosis
Zygomycosis
Esophogeal candidiasis and
cryptococcosis are strong indicators of
AIDS
Zarqa Private UniversityBiology
4223 – The Fungi
PRIMARY ANTI-FUNGAL
AGENTS
1.
2.
Polyene derivatives
 Amphotericin B
 Nystatin
Azoles
 Ketoconazole
 Fluconazole
 Itraconazole
 Voriconazole
Zarqa Private UniversityBiology
4223 – The Fungi
Zarqa Private UniversityBiology
4223 – The Fungi
Azoles
There are a few rare
serious side effects
from Itraconazole and
Fluconazole
Zarqa Private UniversityBiology
4223 – The Fungi
5-fluorocytosine
(5-FC)
Interferes With RNA
Synthesis
Zarqa Private UniversityBiology
4223 – The Fungi
MECHANISMS OF ACTION

Polyenes


Azoles


Griseofulvin


5 - FC

Ergosterol in cell
membrane
Interfere with
ergosterol synthesis
Forms a barrier to
fungal growth
Inhibits RNA
synthesis
Zarqa Private UniversityBiology
4223 – The Fungi