Fungi, Algae, Protozoa, and Helminths

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Fungi, Algae, Protozoa, and Helminths

• The Eukaryotes

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The Fungi

• Eukaryotic
• Aerobic or facultatively anaerobic
• Chemoheterotrophic
• Most are decomposers
• Mycology is the study of fungi

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Molds

• The fungal thallus consists of hyphae a mass of
  hyphae is a mycelium.

Figure 12.2
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Yeasts

• Unicellular fungi
• Fission yeasts divide symmetrically
• Budding yeasts divide asymmetrically

Figure 12.3
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Dimorphism

• Pathogenic dimorphic fungi are yeastlike at 37C
  and moldlike at 25C

Figure 12.4
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Fungal Life Cycle
Figure 12.7
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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

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Protozoa

• Eukaryotic
• Unicellular
• Chemoheterotrophs
• Vegetative form is a trophozoite
• Asexual reproduction by fission, budding, or
  schizogony
• Sexual reproduction by conjugation
• Some produce cysts

Figure 12.16
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Archaezoa

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

Figure 12.17b-d
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Apicomplexa

• Nonmotile
• Intracellular parasites
• Complex life cycles
• Plasmodium
• Babesia
• Cryptosporidium
• Cyclospora

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Plasmodium
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Sporozoites undergo schizogony in liver cell
merozoites are produced
Infected mosquito bites human sporozoites
migrate through bloodstream to liver of human
Sporozoites in salivary gland
Resulting sporozoites migrate to salivary glands
of mosquito
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Merozoites released into bloodsteam from liver
may infect new red blood cells
Sexualreproduction
Asexual reproduction
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In mosquitos digestive tract, gametocytes unite
to form zygote
Zygote
Intermediate host
Female gametocyte
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Merozoite develops into ring stage in red blood
cell
Male gametocyte
Ring stage
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Ring stage grows and divides, producing
merozoites
Definitive host
Another mosquito bites infected humnan and
ingests gametocytes
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Merozoites are released when red blood cell
ruptures some merozoites infect new red blood
cells, and some develop into male and female
gametocytes
Merozoites
Figure 12.19
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Cryptosporidium
Figure 25.19
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Ciliophora (ciliates)

• Move by cilia
• Complex cells
• Balantidium coli is the only human parasite

Figure 12.20
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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

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Euglenozoa
Figure 12.21
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Helminths

• Parasitic worms
• Eukaryotic
• Multicellular animals
• Chemoheterotrophic
• Kingdom Animalia
• Phylum Platyhelminthes (flatworms)
• Class Trematodes (flukes)
• Class Cestodes (tapeworms)
• Phylum Nematodes (roundworms)

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Trematodes
Figure 12.25
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Humans as Definitive Host
Figure 12.26
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Cestodes
Figure 12.27
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Humans as Intermediate Host
Figure 12.28
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Nematodes Eggs Infective for Humans
Figure 12.29
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Nematodes Larvae Infective for Humans
Figure 25.26
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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 (vectors)

Figure 12.31, 32
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Arthropods as Vectors
Figure 12.33
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Putting it Together