Eukarya: Eukaryotic Microorganisms Algae: Phototrophic eukaryotic microorganisms Fungi:...
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Transcript of Eukarya: Eukaryotic Microorganisms Algae: Phototrophic eukaryotic microorganisms Fungi:...
Eukarya: Eukaryotic Microorganisms• Algae: Phototrophic eukaryotic microorganisms• Fungi: Nonphotosynthetic eukaryotic microorga
nisms that contain rigid cell walls• Slime molds: nonphototrophic eukaryotic micro
organisms 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
Phylogenetic tree of Eukaryabased on 18S ribosomal RNAsequence comparisons.
Cells of microsporidia anddiplomonads are phylogeneticallymost ancient of known Eukaryaand contain a nucleus but lackmitochondria
Color of AlgaeMost algae are green in color. A few algae appear brown or red as other pigments including carotenoids are present that mask green
Classification of Algae
• Chlorophyll
• Carbon Reserve Polymers
• Cell Wall Structure
• Type of Motility
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
Molds: filamentous fungi• Hypha (hyphae): a single filament• Mycelium: hyphae grow together formed tufts• Conidia: asexual spores, pigmented, resistant to d
rying
Yeasts: unicellular fungi (ascomycetes)
• Division: budding• Do not form filaments• Some form filaments• Some can mate.
Mushroom: filamentous fungi that typically form large structures called fruiting bodies
Basidiosporereleased frombasidia
Slime molds: phenotypically similar t
o both fungi and protozoa
Acellular slime molds growing ona decaying log
Acellular slime molds growing onan agar surface
Cellular slime molds: vegetative forms composed of single amebalikecells. Acellular slime molds: vegetative forms composed of indefinitesize and shape
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
Mastigophora: the flagellates• Motile by the action of flagella• Many are free-living, some are parasitic, or pathog
enic 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 pathogenicMastigophora are the trypanosomes,which causes African Sleeping Sickness. It lives and grows in human bloodstream, and transmitted from hostto host by the tsetse fly, Glossina sp., abloodsucking fly found over in certainparts o Africa.
Sarcodina: The Amebas
• Naked in the vegetative phase, the foraminefera (带孔虫) 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
Ciliophora: the ciliates• Possess cilia in some stage of their lief cycle• Have two kinds of nuclei: micronucleus for inheritance and sexual re
production: macronucleus for production of mRNA for various
Aspects of cell growth andfunctionThe best known ciliate genus isParameciumMany ciliates obtain food by ingesting particular materialsthrough a distinct oral region or mouthMany Paramecium speciescontain endosymbioic bacteriathat synthesize vitamins or other growth factors.
Sporozoa (孢子虫)• 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 ciliatedprotozoan that causes a dysentry-like disease in human,The dark blue stained structureis the macronucleus
Subphylum Sarcodina肉足虫纲 : locomotion and food gathered by pseudopodia (f
alse foot)
- includes the Amoeba
Clockwise from top right: Flagellate, amoeba, and ciliate. (Photos: Rebecca Stott)