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PowerPoint® Lecture Slide Presentation prepared by Christine L. Case

Microbiology

B.E Pruitt & Jane J. Stein

AN INTRODUCTION

EIGHTH EDITION

TORTORA • FUNKE • CASE

Chapter 12

The Eukaryotes: Fungi, Algae, Protozoa,
and Helminths

The Fungi

Eukaryotic
Aerobic or facultatively anaerobic
Chemoheterotrophic
Most are decomposers, but a few are parasites
Mycology is the study of fungi
Number of serious fungal infections is increasing

List the defining characteristics of fungi.
Differentiate between sexual and asexual reproduction, and describe each of these processes in fungi.

Fungi

Table 12.1

Mycology: The Study of Fungi

Table 12.2

Characteristics of fungal hyphae:

Separate hyphae have cross-walls or septa
Coenocytic hyphae lack septa
Hyphae grow by elongating at tips

Molds

Aerial (with reproductive spores) and vegetative hyphae
The fungal thallus consists of hyphae; a mass of hyphae is a mycelium.

Figure 12.2

Yeasts – various stages of budding

Unicellular fungi
Fission yeasts divide symmetrically
Budding yeasts divide asymmetrically

Figure 12.3

Fungal Dimorphism

Pathogenic dimorphic fungi are yeastlike at 37°C and moldlike at 25°C
On agar surface, Mucor rouxii exhibits yeastlike growth; in agar it is moldlike

Figure 12.4

Conidiospores: Representative asexual spores

Figure 12.5

Conidia arranged in chains on Aspergillus flavus

Fungi classified by type of sexual spore
Sexual spores usually produced in response to special changes in environment

Life cycle of Rhizopus, a zygomycete: produces asexually usually

Fungal Life Cycle

Figure 12.7

Life cycle of Talaromyces, an ascomycete: occasional sexual union of two strains

Fungal Diseases (mycoses)

Systemic mycoses Deep within body
Subcutaneous mycoses Beneath the skin
Cutaneous mycoses Affect hair, skin, nails
Superficial mycoses Localized, e.g., hair shafts
Opportunistic mycoses Caused by normal microbiota or fungi that are normally systemic, but can infect any tissue

Asexual spores

Sporangiosphore
Conidiospore
Arthrospore
Blastoconidium
Chlamydospore

Figure 12.1

Sexual reproduction

Plasmogamy Haploid donor cell nucleus (+) penetrates cytoplasm of
recipient cell (–)
Karyogamy + and – nuclei fuse
Meiosis Diploid nucleus produces
haploid nuclei (sexual spores)

Sexual spores

Zygospore Fusion of haploid cells produces
one zygospore

Figure 12.6

Sexual spores

Ascospore Formed in a sac (ascus)

Figure 12.7

Sexual spores

Basidiospore Formed externally on a pedestal
(basidium)

Figure 12.8

PowerPoint® Lecture Slide Presentation prepared by Christine L. Case

Microbiology

B.E Pruitt & Jane J. Stein

AN INTRODUCTION

EIGHTH EDITION

TORTORA • FUNKE • CASE

Chapter 12, part B

The Eukaryotes: Fungi, Algae, Protozoa, and Helminths

List the defining characteristics of the three phyla of fungi described in this chapter.

Zygomycota

Conjugation fungi. Coenocytic. Produce sporangiospores and zygospores.
Rhizopus, Mucor (Opportunistic, systemic mycoses)

Generalized life cycle of a basidiomycete

Zygomycete Life Cycle

Ascomycota

Sac fungi. Septate. Produce ascospores and frequently conidiospores.
Aspergillus (opportunistic, systemic mycosis)
Blastomyces dermatitidis, Histoplasma capsulatum (systemic mycoses)
Microsporum, Trichophyton (cutaneous mycoses)

Ascomycete Life Cycle

Figure 12.7

Basidiomycota

Club fungi. Septate. Produce basidiospores and sometimes conidiospores.
Cryptococcus neoformans (systematic mycosis)

Representative basidiomycetes: bird’s nest fungus on twig and mushroom-like form

Basidiomycete Life Cycle

Figure 12.8

Anamorphs

Teleomorphic fungi:
Produce sexual and asexual spores.
Anamorphic fungi:
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)

Identify two beneficial and two harmful effects of fungi.

Economic Effects of Fungi

Fungi	Positive Effects	Negative Effects
Saccharomyces	Bread, wine, beer	Food spoilage
Trichoderma	Cellulose used for juices and fabric	Cryphonectria parasitica (chestnut blight)
Taxomyces	Taxol production	Ceratocystis ulm (Dutch elm disease)
Entomorphaga	Gypsy moth control

Lichens

Mutualistic combination of an alga (or cyanobacterium) & fungus
Alga produces and secretes carbohydrates, fungus provides holdfast
Lichens colonize habitats unsuitable for alga or fungus alone
Lichens classified by morphology: crustose, foliose, or fruticose

Describe the roles of the fungus and the alga in a lichen.

Lichens

Figure 12.10

List the distinguishing characteristics of lichens, and describe their nutritional needs.

The Algae

Eukaryotic
Unicellular, filamentous, or multicellular (thallic)
Most are photoautotrophs and aquatic
Produce 30 – 50 % of world’s oxygen
Reproduce asexually by cell division and fragmentation
Classified according to structures and pigments
Primary producers in the aquatic food chain

List the defining characteristics of algae.
List the outstanding characteristics of the five divisions of algae discussed in this chapter.

Algae

Table 12.1

Algae and their habitats

Figure 12.11a

Green Algae

Figure 12.12b

Phaeophyta

Brown algae (kelp)
Cellulose + alginic acid cell walls
Multicellular
Chlorophyll a and c, xanthophylls
Store carbohydrates
Harvested for algin

Figure 12.11b

Rhodophyta

Red algae
Cellulose cell walls
Most multicellular
Chlorophyll a and d, phycobiliproteins
Store glucose polymer
Harvested for agar and carrageenan

Figure 12.11c

Chlorophyta

Green algae
Cellulose cell walls
Unicellular or multicellular
Chlorophyll a and b
Store glucose polymer
Gave rise to plants

Figure 12.12a

Bacillariophyta

Diatoms
Pectin and silica cell walls
Unicellular
Chlorophyll a and c, carotene, xanthophylls
Store oil
Fossilized diatoms formed oil
Produce domoic acid

Figure 12.13

Dinoflagellata

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

Figure 12.14

Oomycota

Water molds
Cellulose cell walls
Multicellular
Chemoheterotrophic
Produce zoospores
Decomposers and plant parasites
Phytophthora infestans responsible for Irish potato blight
P. cinnamomi infects Eucalyptus
P. ramorum causes sudden oak death

Figure 12.15

PowerPoint® Lecture Slide Presentation prepared by Christine L. Case

Microbiology

B.E Pruitt & Jane J. Stein

AN INTRODUCTION

EIGHTH EDITION

TORTORA • FUNKE • CASE

Chapter 12, part C

The Eukaryotes: Fungi, Algae, Protozoa, and Helminths

List the defining characteristics of protozoa.
Describe the outstanding characteristics of the seven phyla of protozoa discussed in this chapter,and give an example of each.

The Protozoa

Table 12.1

Protozoa: Conjugation in ciliate Paramecium

Eukaryotic – soil, water, microbiota in animals
Unicellular
Chemoheterotrophs
Vegetative form is a trophozoite
Asexual reproduction by fission, budding, or schizogony
Sexual reproduction by conjugation
Some produce cysts for survival

Figure 12.16

Archaezoa

No mitochondria
Multiple flagella
Giardia lamblia
Trichomonas vaginalis (no cyst stage)

Figure 12.17b-d

Microspora

No mitochondria or microtubules
Cause diarrhea in AIDS patients
Non-motile
Intracellular parasites
Nosema

Move by pseudopods
Entamoeba
Acanthamoeba

Rhizopoda (amoebas)

Entamoeba histolytica – ingested red blood cells diagnostic for this

Apicomplexa

Apical organelles for penetrating host tissue
Nonmotile
Intracellular parasites
Complex life cycles
Plasmodium (in two slides)
Babesia
Cryptosporidium (next slide)
Cyclospora

Cryptosporidium

Figure 25.19

Plasmodium

Figure 12.19

Infected mosquito bites human; sporozoites
migrate through
bloodstream to
liver of human

Sporozoites undergo schizogony in liver cell; merozoites are produced

Merozoites released into bloodsteam from liver may infect new red blood cells

Merozoites are released when red blood cell ruptures; some merozoites infect new red blood cells, and some develop into male and female gametocytes

Asexual
reproduction

Intermediate host

Merozoite develops into ring stage in red blood cell

Ring

stage

Merozoites

Another mosquito bites infected humnan and ingests gametocytes

Ring stage grows and divides, producing merozoites

Definitive host

In mosquito’s digestive tract, gametocytes unite to form zygote

Male
gametocyte

Female
gametocyte

Zygote

Sexual
reproduction

Resulting sporozoites migrate to salivary glands of mosquito

Sporozoites in salivary gland

Ciliophora (ciliates)

Move by cilia
Complex cells
Paramecium has specialized structures (mouth for ingestion, anal pore, contractile vacuoles)
Balantidium coli is the only human parasite
Vorticella attaches by base of its stalk

Figure 12.20

Euglenozoa

Move by flagella
Photoautotrophs
Euglenoids
Chemoheterotrophs
Naegleria
Flagellated and amoeboid forms, meningoencephalitis
Trypanosoma
Undulating membrane, transmitted by vectors
Leishmania
Flagellated form in sand fly vector, ovoid form in vertebrate host

Euglenozoa

Figure 12.21

Cellular Slime Molds

Cellular slime molds
Resemble amoebas, ingest bacteria by phagocytosis
Cells aggregate into stalked fruiting body.
Some cells become spores

Plasmodial slime molds
Multinucleated large cells
Cytoplasm separates into stalked sporangia
Nuclei undergo meiosis and form uninucleate haploid spores

Compare and contrast cellular slime molds and plasmodial slime molds.

Cellular Slime Mold

Figure 12.22

Plasmodial Slime Mold

Figure 12.23

The Helminths

List the distinguishing characteristics of parasitic helminths.

Table 12.1

List the distinguishing characteristics of parasitic helminths.

Infection by parasitic platyhelminth:

may be due to fertilizer runoff that increases algae

Helminths (parasitic worms)
Eukaryotic
Multicellular animals
Chemoheterotrophic
Kingdom: Animalia
Phylum: Platyhelminthes (flatworms)
Class: Trematodes (flukes)
Class: Cestodes (tapeworms)
Phylum: Nematodes (roundworms)
Adult stage parasitic helminth found in definitive host
Larval stage found in intermediate host

Provide a rationale for the elaborate life cycles of parasitic worms.

Trematodes: Flukes

Figure 12.25

Heavy infestations may block bile ducts from the liver

Describe a parasitic infection in which humans serve as a definitive host, as an intermediate host,and as both.

Humans as Definitive Host (Lung Fluke)

Figure 12.26

Differentiate between an intermediate host and a definitive host.

Humans as Intermediate Host

Figure 12.28

Tapeworm Echinococcus granulosus, in intestines of canines

Cestodes: Adult Tapeworm

Figure 12.27

Humans serve as definitive host for beef tapeworm, and cattle are the intermediate host

Humans serve a definitive host and can be intermediate host for pork tapeworm

Humans serve as intermediate host for Echinocossus granulosus, definitive hosts are canines spp.

Nematodes: Eggs Infective for Humans

Figure 12.29

Roundworms have a complete digestive system.
Pinworm Enterobius vermicularis, eggs deposited by female on perianal skin at night.

Hookworm

Necator americanus – free-living larvae inhabit soil and infect definitive human host by penetrating skin

List the characteristics of the three groups of parasitic helminths, and give an example of each.

Nematodes: Larvae Infective for Humans

Figure 25.26

Define arthropod vector.

Arthropods as Vectors

Kingdom: Animalia
Phylum: Arthropoda (exoskeleton, jointed legs)
Class: Insecta (6 legs)
Lice, fleas, mosquitoes
Class: Arachnida (8 legs)
Mites and ticks
May transmit diseases called vectors

Figure 12.31, 32

Differentiate between a tick and a mosquito, and name a disease transmitted by each.

Arthropods as Vectors

Figure 12.33