Eukarya: Eukaryotic Microorganisms

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Eukarya Eukaryotic Microorganisms

• Algae Phototrophic eukaryotic microorganisms
• Fungi Nonphotosynthetic eukaryotic
  microorganisms that contain rigid cell walls
• Slime molds nonphototrophic eukaryotic
  microorganisms that lack cell walls and that
  aggregate to form fruiting structures (cellular
  slime molds) or masses of protoplasm (acellular
  slime molds)
• Protozoa unicellular eukaryotic microorganisms
  that lack cell walls

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Phylogenetic tree of Eukarya based on 18S
ribosomal RNA sequence comparisons.
Cells of microsporidia and diplomonads are
phylogenetically most ancient of known
Eukarya and contain a nucleus but
lack mitochondria
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Eukaryotic Microorganisms

• Algae
• Fungi
• Slime Molds
• Protozoa

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Algae
Most Algae are green in color
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Color of Algae
Most algae are green in color. A few algae appear
brown or red as other pigments including
carotenoids are present that mask green
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Classification of Algae

• Chlorophyll
• Carbon Reserve Polymers
• Cell Wall Structure
• Type of Motility

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Fungi Molds, Yeasts and Mushrooms

• Habitats diverse aquatic in fresh water or
  marine, terrestrial in soil or on dead plant, a
  few are human parasitic
• Have rigid cell walls (resemble plant cell walls
  architecturally, not chemically) containing
  chitin (some with mannans, galactosans, chitosans
  instead of chitin)
• Fungal cell walls are 80-90 polysaccharide, with
  proteins, lipids, polyphosphates and inorganic
  ions making up the wall-cementing matrix

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Classification of Fungi

• Based on
• morphological properties
• sexual life cycles

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Molds filamentous fungi

• Hypha (hyphae) a single filament
• Mycelium hyphae grow together formed tufts
• Conidia asexual spores, pigmented, resistant to
  drying

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Yeasts unicellular fungi (ascomycetes)

• Division budding
• Do not form filaments
• Some form filaments
• Some can mate.

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Mushroom filamentous fungi that typically form
large structures called fruiting bodies
Basidiospore released from basidia
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Slime molds phenotypically similar to both fungi
and protozoa
Cellular slime molds vegetative forms composed
of single amebalike cells. Acellular slime molds
vegetative forms composed of indefinite size and
shape
Acellular slime molds growing on an agar surface
Acellular slime molds growing on a decaying log
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Dictyostelium discoideum in various life stages
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Protozoa

• Colorless
• Motile
• distinguished from prokaryotes by their greater
  size and eukaryotic nature
• distinguished from algae by their greater lack of
  chlorophyll
• distinguished from yeasts and other fungi by
  their mobility and lack of cell wall
• distinguished from slime molds by their lack of
  fruiting body formation
• Many of them are parasitic in other animals and
  human

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Amoeba
Flagellate (Dunaliella)
Sporozoan (Plasmodium vivax)
Ciliate (Paramecium)
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Mastigophora the flagellates

• Motile by the action of flagella
• Many are free-living, some are parasitic, or
  pathogenic for animals, including human
• They are rather small, about 20 microns in length
• Trypanosoma gambiense is the species that cause
  the fatal and chronic African Sleeping Sickness

The most important pathogenic Mastigophora are
the trypanosomes, which causes African Sleeping
Sickness. It lives and grows in human
bloodstream, and transmitted from host to host
by the tsetse fly, Glossina sp., a bloodsucking
fly found over in certain parts o Africa.
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Sarcodina The Amebas

• Naked in the vegetative phase, the foraminefera
  (???)secretes a shell during vegetative growth
• Many amoebas are parasites of human and other
  vertebrates
• In some cases, they produce ulceration of the
  intestinal
• tract, which results in a diarrheal conditions
  called amebiasis

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Ciliophora the ciliates

• Possess cilia in some stage of their lief cycle
• Have two kinds of nuclei micronucleus for
  inheritance and sexual reproduction macronucleus
  for production of mRNA for various

Aspects of cell growth and function
The best known ciliate genus is Paramecium Many
ciliates obtain food by ingesting particular
materials through a distinct oral region or
mouth Many Paramecium species contain
endosymbioic bacteria that synthesize vitamins or
other growth factors.
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Sporozoa (???)

• Obligate parasites
• Lack of motile adult stages
• Absorb food in soluble form through outer wall
• Produce sporozoites for transmission to new host
• Most important coccidia, parasites of birds and
  plasmodia (malaria parasites)

Balantidium coli, a ciliated protozoan that
causes a dysentry-like disease in human, The
dark blue stained structure is the macronucleus