Transcript Microbiology - Imperial Valley College Faculty Websites

Chapter 12
The Eukaryotes:
Fungi, Algae,
Protozoa, and
Helminths
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Lectures prepared by Christine L. Case
Q&A
 During the Great Irish
Famine of the mid–
nineteenth century, well
over 1 million people died
or were displaced because
of the devastating effects
of Phytophthora infestans,
an alga that infects potato
crops. What damage is
Phytophthora causing in
other parts of the world
today?
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Fungi
Kingdom
Fungi
Nutritional Type
Chemoheterotroph
Multicellularity
All, except yeasts
Cellular Arrangement
Unicellular, filamentous,
fleshy
Food Acquisition Method
Absorptive
Characteristic Features
Sexual and asexual spores
Embryo Formation
None
Mycology is the study of fungi
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Table 12.2
Molds
 The fungal thallus consists of hyphae; a mass of
hyphae is a mycelium.
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Figure 12.2
Yeasts
 Unicellular fungi
 Fission yeasts divide symmetrically
 Budding yeasts divide asymmetrically
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Figure 12.3
Vegetative Growth
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Figure 12.1
Fungal Dimorphism
 Pathogenic dimorphic fungi are yeastlike at 37°C
and moldlike at 25°C
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Figure 12.4
Asexual Reproduction
 Conidia or conidiospores
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Figure 12.5a
Asexual Reproduction
 Arthroconidia
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Figure 12.5b
Asexual Reproduction
 Blastoconidia
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Figure 12.5c
Asexual Reproduction
 Chlamydoconidia
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Figure 12.5d
Asexual Reproduction
 Sporangiospores
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Figure 12.5e
Sexual Reproduction
 Three phases:
 Plasmogamy: Haploid donor cell nucleus (+) penetrates
cytoplasm of recipient cell (–)
 Karyogamy: + and – nuclei fuse
 Meiosis: Diploid nucleus produces haploid nuclei (sexual
spores)
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Sexual Spores
 Zygospore: Fusion of haploid cells produces one
zygospore
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Figure 12.6
Sexual Spores
 Ascospore: Formed in a sac (ascus).
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Figure 12.7
Sexual Spores
 Basidiospore: Formed externally on a pedestal
(basidium)
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Figure 12.8
Medically Important Phyla of Fungi




Zygomycota
Ascomycota
Anamorphs
Basidiomycota
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Zygomycota
 Conjugation fungi
 Coenocytic
 Produce sporangiospores and zygospores
 Rhizopus, Mucor (opportunistic, systemic mycoses)
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The Life Cycle of a Zygomycete
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Figure 12.6
Ascomycota
 Sac fungi
 Septate
 Teleomorphic fungi
 Produce sexual and asexual spores
 Ascospores and frequently conidiospores
 Aspergillus (opportunistic, systemic mycosis)
 Blastomyces dermatitidis, Histoplasma capsulatum
(systemic mycoses)
 Microsporum, Trichophyton (cutaneous mycoses)
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The Life Cycle of an Ascomycete
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Figure 12.7
Anamorphs
 Produce asexual spores only
 rRNA sequencing places most in Ascomycota; a few are
Basidiomycota
 Penicillium
 Sporothrix (subcutaneous mycosis)
 Stachybotrys, Coccidioides, Pneumocystis (systemic
mycoses)
 Candida albicans (cutaneous mycoses)
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Basidiomycota
 Club fungi
 Septate
 Produce basidiospores and sometimes
conidiospores
 Cryptococcus neoformans (systemic mycosis)
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The Life Cycle of a Basidiomycete
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Figure 12.8
Economic Effects of Fungi
 Saccharomyces cerevisiae: Bread, wine, HBV
vaccine
 Trichoderma: Cellulase
 Taxomyces: Taxol
 Entomophaga: Biocontrol
 Paecilomyces: Kills termites
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Fungal Diseases (Mycoses)

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Systemic mycoses: Deep within body
Subcutaneous mycoses: Beneath the skin
Cutaneous mycoses: Affect hair, skin, and nails
Superficial mycoses: Localized, e.g., hair shafts
Opportunistic mycoses: Caused by normal
microbiota or environmental fungi
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Lichens
 Mutualistic combination of an alga (or
cyanobacterium) and fungus
 Alga produces and secretes carbohydrates; fungus
provides holdfast
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Three Types of Lichens
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Figure 12.9a
Lichen Thallus
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Figure 12.9b
Economic Effects of Lichens
 Dyes
 Antimicrobial (Usnea)
 Litmus
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Algae
Kingdom
Protist
Nutritional Type
Photoautotroph
Multicellularity
Some
Cellular Arrangement
Unicellular, colonial,
filamentous, tissues
Food Acquisition Method
Diffusion
Characteristic Features
Pigments
Embryo Formation
None
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Algal Habitats
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Figure 12.10a
Brown Alga
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Figure 12.11b
Phaeophyta
 Brown algae (kelp)
 Cellulose and alginic
acid cell walls
 Multicellular
 Chlorophyll a and c,
xanthophylls
 Store carbohydrates
 Harvested for algin
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Figure 12.10b
Rhodophyta


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
Red algae
Cellulose cell walls
Most are multicellular
Chlorophyll a and d,
phycobiliproteins
 Store glucose
polymer
 Harvested for agar
and carrageenan
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Figure 12.10c
Chlorophyta
 Green algae
 Cellulose cell walls
 Unicellular or
multicellular
 Chlorophyll a and b
 Store glucose polymer
 Gave rise to plants
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Figure 12.11a
Diatoms
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Pectin and silica cell walls
Unicellular
Chlorophyll a and c, carotene, xanthophylls
Store oil
Fossilized diatoms formed oil
Produce domoic acid
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Diatoms
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Figure 12.12a
Asexual Reproduction of a Diatom
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Figure 12.12b
Dinoflagellates
 Cellulose in plasma
membrane
 Unicellular
 Chlorophyll a and c,
carotene, xanthins
 Store starch
 Some are symbionts in
marine animals
 Neurotoxins cause
paralytic shellfish
poisoning
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Figure 12.13
Oomycota

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Water molds
Cellulose cell walls
Multicellular
Chemoheterotrophic
Produce zoospores
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Figure 12.14
Oomycota
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Figure 12.14
Oomycota
 Decomposers and
plant parasites
 Phytophthora
infestans
responsible for Irish
potato blight
 P. cinnamoni infects
Eucalyptus
 P. ramorum causes
sudden oak death
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Figure 12.14
Protozoa
Kingdom
Protist
Nutritional Type
Chemoheterotroph
Multicellularity
None
Cellular Arrangement
Unicellular
Food Acquisition Method
Absorptive; ingestive
Characteristic Features
Motility; some form cysts
Embryo Formation
None
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Characteristics of Protozoa
 Vegetative form is a trophozoite
 Asexual reproduction is by fission, budding, or
schizogony
 Sexual reproduction by conjugation
 Some produce cysts
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Medically Important Phyla of Protozoa
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Archaezoa
Microspora
Amoebozoa
Apicomplexa
Ciliophora
Euglenozoa
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Archaezoa
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No mitochondria
Multiple flagella
Giardia lamblia
Trichomonas
vaginalis (no cyst
stage)
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Figure 12.16b
Archaezoa
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Figure 12.16c, d
Microspora


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No mitochondria
Nonmotile
Intracellular parasites
Nosema
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Amoebozoa
 Move by
pseudopods
 Entamoeba
 Acanthamoeba
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Figure 12.17a
Apicomplexa

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Nonmotile
Intracellular parasites
Complex life cycles
Plasmodium
Babesia
Cryptosporidium
Cyclospora
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The Life Cycle of Plasmodium vivax
2
3
8
7
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6
Figure 12.18
Cryptosporidium
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Clinical Focus, p. 355
Cryptosporidium
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Clinical Focus, p. 355
Ciliates
 Move by cilia
 Complex cells
 Balantidium coli
is the only
human parasite
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Figure 12.19
Euglenozoa
 Move by flagella
 Euglenoids
 Photoautotrophs
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Figure 12.20
Euglenozoa
 Move by flagella
 Hemoflagellates
 Trypanosoma spp.
 Sleeping
sickness
 Chagas’
disease
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Figure 23.22
The Life Cycle of a Cellular Slime Mold
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Figure 12.21
The Life Cycle of a Plasmodial Slime
Mold
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Figure 12.22
Helminths
Kingdom
Animalia
Nutritional Type
Chemoheterotroph
Multicellularity
All
Cellular Arrangement
Tissues and organs
Food Acquisition Method
Ingestive; absorptive
Characteristic Features
Elaborate life cycles
Embryo Formation
All
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Helminths (Parasitic Worms)
 Kingdom: Animalia
 Phylum: Platyhelminthes (flatworms)
 Class: Trematodes (flukes)
 Class: Cestodes (tapeworms)
 Phylum: Nematoda (roundworms)
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Characteristics of Helminths

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Reduced digestive system
Reduced nervous system
Reduced locomotion
Complex reproduction
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Life Cycle of Helminths
 Monoecious (hermaphroditic)
 Male and female reproductive systems in one animal
 Dioecious
 Separate male and female
 Egg  larva(e)  adult
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Trematodes, or Flukes
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Figure 12.24
The Life Cycle of Trematodes
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Figure 12.25
Cestodes, or Tapeworms
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Figure 12.26
Human as
Definitive Host
Taenia saginata
Cysticerci in beef
muscle
Intermediate
Host
Echinococcus
granulosus
Adult in dog
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Humans as Intermediate Host
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Figure 12.27
Nematodes
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Figure 12.28
The Heartworm Dirofilaria immitis
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Figure 12.29
Eggs Infective for Humans
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Figure 12.28
Larvae Infective for Humans
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Figure 25.23
Arthropods as Vectors
 May transmit diseases (vectors)
 Kingdom: Animalia
 Phylum: Arthropoda (exoskeleton, jointed legs)
 Class: Insecta (6 legs)
 Lice, fleas, mosquitoes
 Class: Arachnida (8 legs)
 Mites and ticks
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Arthropods as Vectors
 Mechanical
transmission
 Biological
transmission
 Microbe multiplies
in vector
 Definitive host
 Microbe’s sexual
reproduction in
vector
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Figure 12.30
Arthropods as Vectors
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Figure 12.31
Arthropods as Vectors
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Figure 12.32