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The Eukaryotic Members
of the Microbial World
Chapter 12
12.1 Algae
Engage in photosynthesis
Fresh and salt water habitats
Phytoplankton
Structural composition
Cell wall
Nucleus
Chloroplast
Mitochondria
12.1 Algae (cont.)
Toxins
Algae do not infect animals
However, many produce toxins
Brevetoxin is associated with red tide
Various shellfish toxins
neurotoxins
saxitoxin (dizziness, diarrhea and vomiting,
disorientation, respiratory distress)
gonyautoxins (paralysis)
12.2 Protozoa
Free-living single-celled organisms
Highly motile
Nutritional acquisition
Decomposers
Predators
The largest genome belongs to a protozoan
Amoeba dubia - 6.7 x 1011 nucleotides
Highly motile
Cilia
Flagella
Pseudopodia
12.2 Protozoa (cont.)
Diseases caused by protozoa
Toxoplasmosis (Toxoplasma gondii)
Schizophrenia?
African sleeping sickness (Trypanosoma
sp.)
Malaria (Plasmodium sp.)
Amoebic dysentery
Giardiasis (Giardia sp.)
Leishmaniasis (Leishmania sp.)
Cryptosporidiosis (Cryptosporidium sp.)
12.3 Fungi
Yeasts, molds and mushrooms
Most are aerobes or facultative anaerobes
Nutritional acquisition is primarily through
absorption of dead organisms or organic
matter
Some exhibit dimorphism
Exist as single-celled yeast, or...
Multicellular organisms
Some are fermenters
12.3 Fungi (cont.)
Diseases
Fungal diseases are termed mycoses
Mycoses are rare in immunocompetent people
Topical
or
superficial
mycoses
are
usually
treatable
Visceral mycoses are serious, often fatal
Toxins
Aflatoxins
(Aspergillus
sp.)
are
hepatotoxic
(cancer)
Halucinogenic mushrooms
Amatoxin (mushrooms) inhibits RNA pol II
Antibiotics
Penicillin
Griseofulvin (for athlete’s foot)
12.5 Multicellular Parasites:
Arthropods and Helminths
Arthropods
Vectors for infectious diseases
Mosquitos
Ticks
Fleas
12.5 Multicellular Parasites: Arthropods
and Helminths (cont.)