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
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
Eukaryotic Microorganisms • Algae • Fungi • Slime Molds • Protozoa
Algae Most Algae are green in color
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
Classification of Algae • Chlorophyll • Carbon Reserve Polymers • Cell Wall Structure • Type of Motility
绿藻 蜂窝藻 眼藻 金藻 暗藻 甲藻 红藻
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
Classification of Fungi • Based on • morphological properties • sexual life cycles
Molds: filamentous fungi • Hypha (hyphae): a single filament • Mycelium: hyphae grow together formed tufts • Conidia: asexual spores, pigmented, resistant to drying
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 Basidiospore released from basidia
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
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
Amoeba Flagellate （Dunaliella） Sporozoan (Plasmodium vivax) Ciliate （Paramecium）
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.
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 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.
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 ciliated protozoan that causes a dysentry-like disease in human, The dark blue stained structure is the macronucleus
Subphylum Sarcodina肉足虫纲:locomotion and food gathered by pseudopodia (false foot)- includes the Amoeba
Clockwise from top right: Flagellate, amoeba, and ciliate. (Photos: Rebecca Stott)