CSLO5. Describe evidence for the evolution of cells, organelles and major metabolic pathways from early prokaryotes and how phylogenetic trees reflect evolutionary relationships. CSLO6. Compare characteristics and replication of acellular infectious agents (viruses and prions) with characteristics and reproduction of cellular infectious agents (prokaryotes and eukaryotes). PowerPoint Lecture Presentations prepared by Mindy Miller-Kittrell, North Carolina State University C H A P T E R 12 Characterizing and Classifying Eukaryotes
Eukaryotic microorganisms Include both human pathogens and organisms vital for human life Protozoa Fungi Algae Water molds Slime molds
Reproduction of Eukaryotes CONCEPT 12.1 Some show asexual reproduction Many reproduce sexually by forming gametes and zygotes More complicated than that in prokaryotes because Eukaryotic DNA packaged as chromosomes in the nucleus so nuclear division needed (1) Mitosis (2) Meiosis
CONCEPT 12.2 FACT 12.1 Mitosis 1) Cell partitions replicated DNA equally between two nuclei 2) Maintains ploidy of parent nucleus diploid produces diploid 3) Four phases Prophase Metaphase Anaphase Telophase Cytokinesis (cytoplasmic division) 1 cell becomes 2 cells
CONCEPT 12.3 FACT 12.2 Meiosis 1) Cell partitions replicated DNA unequally between 4 nuclei 2) diploid nuclei produce haploid daughter nuclei 3) Two stages meiosis I and meiosis II Each stage has four phases Prophase Metaphase Anaphase Telophase Cytokinesis (cytoplasmic division) 1 cell becomes 4 cells
MEIOSIS I Figure 12.1b The two kinds of nuclear division: mitosis and meiosis (1 of 2). Meiosis CONCEPT 12.3 Diploid nucleus (2n) DNA replication 1 Prophase I FACT 12.2 Tetrad (two homologous chromosomes, four chromatids) 2 Late prophase I Crossing over 3 Metaphase I 4 Anaphase I Chromosome (two chromatids) 5 Telophase I
MEIOSIS II Figure 12.1b The two kinds of nuclear division: mitosis and meiosis (2 of 2). Meiosis Chromosome (two chromatids) 5 Telophase I CONCEPT 12.3 FACT 12.2 6 Prophase II 7 Metaphase II 8 Anaphase II 9 Telophase II Nuclear envelope Four haploid nuclei (1n)
Wall of parent cell Nuclei of daughter cells Vesicles forming cell plate Cleavage furrow plant cells = cell plate Bud Animal cells = cleavage furrow fungal cells = bud CONCEPT 12.4 Figure 12.2 Different types of cytoplasmic division. FACT 12.3
Schizogony Special type of division seen in some Cytokinesis is delayed multinucleated cells seen FACT 12.4 Merozoites Nucleus Schizont Multiple mitoses Cytokinesis
Protozoa CONCEPT 12.5 FACT 12.5 Diverse group defined by three characteristics 1) Eukaryotic 2) Unicellular 3) lack a cell wall So how do they survive in hypotonic environment? Some have contractile vacuoles that pump water out of cells For osmoregulation
FACT 1.3 Eukaryotic Microbes unicellular Protozoa (microanimals) Similar to animals in nutrient needs and cellular structure Live freely in water; some live in animal hosts Motile by means of cilia, flagella or pseudopodia Amoeba Pseudopods cell extensions that flow in direction of travel Blepharisma Cilia numerous short protrusions that propel organisms through its environment Peranema Flagella extensions of a cell that are fewer, longer, and more whiplike than cilia
Where do you find Protozoa moist environments (ponds, streams, lakes, and oceans) Very few are pathogens Morphology of Protozoa Great morphological diversity Some have two nuclei CONCEPT 12.6 Macronucleus (multiple copies of the genome) Micronucleus (single copy of the genome) Variety in number and kinds of mitochondria
Figure 12.6 Sexual reproduction via conjugation in ciliates. Diploid micronuclei Compatible mates 1 Mates couple. 2 Meiosis of micronuclei produces four haploid micronuclei in each. 3 Three micronuclei in each disintegrate; the remaining two replicate by mitosis. Haploid micronuclei 4 Mates each swap one micronucleus. Haploid micronucleus (1n) Macronucleus (50n) Diploid micronucleus (2n) 5 Partners separate. 9 Three cytokineses partition a macronucleus and a micronucleus into each of four daughter cells. 8 Original macronucleus disintegrates. Four micronuclei become macronuclei by replicating chromosomes numerous times; four micronuclei remain micronuclei. 7 Three mitoses without cytokinesis produce eight micronuclei. 6 The two different micronuclei fuse to form diploid micronucleus.
CONCEPT 12.7 The life cycle of Protozoa has different stages Motile feeding stage called a trophozoite Resting stage called a cyst
Classification of Protozoa Classification of protozoa has shifted over the years Revised and updated based on 18s rrna sequences One current scheme groups protozoa into six groups 1) Parabasala 2) Diplomonadida 3) Euglenozoa 4) Alveolates 5) Amoebozoa 6) Rhizaria
Classification of Protozoa 1) Parabasala FACT 12.6 Contain Golgi body like structure called a parabasal body Figure 12.7 Trichonympha acuta, a parabasalid with prodigious flagella. Important parabasalids Trichonympha Trichomonas Trichomonas vaginalis, which causes a sexually transmitted disease in humans Hydrogenosomes (like mitochondria) typical mitochondria Is absent
Classification of Protozoa 2) Diplomonadida (2 nuclei- double cells) FACT 12.7 Lack mitochondria modified mitochondria-like organelles called mitosomes in the cytoplasm Have two equal-sized nuclei and multiple flagella Giardia causes Giardiasis(beaver fever)
3) Euglenozoa Two groups 3a) Euglenids 3b) Kinetoplastids FACT 12.8 Mitochondria have disk-shaped cristae 3a) Euglenids Photoautotrophic Both animal and plant-like features Chloroplast Flagella, Eyespot
3) Euglenozoa FACT 12.9 3b) Kinetoplastids Have multiple copies of mitochondrial DNA called a kinetoplast Kinetoplast Some kinetoplastids are pathogenic Trypanosoma Trypanosomes infect a variety of hosts and cause various diseases, including the fatal human diseases sleeping sickness, caused by Trypanosoma brucei
sleeping sickness, caused by Trypanosoma brucei
4) Alveolates Have membrane-bound cavities called alveoli FACT 12.10 Divided into three subgroups 4a) Ciliates 4b) Apicomplexans 4c) Dinoflagellates
4a) Ciliates FACT 12.11 Use cilia to move themselves or water All are chemoheterotrophs and have two nuclei Balantidium is the only ciliate pathogenic to humans
4b) Apicomplexans Chemoheterotrophic pathogens of animals Obligate endoparasites FACT 12.12 Complex of organelles allow them to penetrate host cells apical complex burrow Plasmodium and Toxoplasma cause disease in humans
Plasmodium
4c) Dinoflagellates FACT 12.13 Unicellular microbes with photosynthetic pigments Historically classified as algae Motile dinoflagellates have two flagella
Dinoflagellates forms Large proportion of freshwater and marine plankton FACT 12.13 Planktons especially phytoplankton support foodchain and life
Many dinoflagellates are bioluminescent Abundance in marine water is one cause of red tides some red tides kill because dinoflagellates produce neurotoxins
5) Amoebozoa FACT 12.14 Amoebae with lobe-shaped pseudopods and no shells Includes some human pathogens Entamoeba Slime molds are now classified as amoebozoa 1) Plasmodial slime molds 2) Cellular slime molds
FACT 12.14 Plasmodial slime molds Cellular slime molds
6) Rhizaria - Amoebae with shells that move and feed with thread-like pseudopods FACT 12.15 Foraminifera Have ornate shells of calcium carbonate Both constitute the marine zooplankton Radiolaria Have ornate shells of silica
Fungi Chemoheterotrophic acquire nutrients by absorption Have cell walls typically composed of chitin Do not perform photosynthesis - Lack chlorophyll The Significance of Fungi Decomposers Decompose dead organisms and recycle their nutrients Most are saprobes (living on dead) CONCEPT 12.8 FACT 12.16
FACT 12.17 Help plants absorb water and minerals mycorrhizae
mycelium hyphae Fungus has 2 basic body shapes 1) Hyphae (moldlike shape) 2) Single celled (yeastlike shape) 3) Mixed (dimorphic or both)
The Significance of Fungi Mold (hyphae) Produce antibiotics and other drugs Penicillium
The Significance of Fungi Saccharomyces (Yeast) single celled Used for food and in manufacture of foods and beverages
30% of fungus cause diseases of plants, animals, and humans Can spoil fruit, pickles, jams, and jellies Candida albicans is an opportunistic pathogenic yeast that is a common member of the human gut flora and also causes yeast infection. Candida albicans (a type of Yeast) mixed
Fungi- Photosynthetic Partnership Lichens Partnerships between 1) Fungi - provides nutrients, water, and protection 2) Photosynthetic microbes - provides carbohydrates and oxygen Create soil from weathered rocks Eaten by many animals CONCEPT 12.9 Abundant throughout the world Grow in almost every habitat
Algae Simple, eukaryotic phototrophs CONCEPT 12.10 Carry out oxygenic photosynthesis using chlorophyll a Most are aquatic Can have different morphologies Unicellular Colonial Simple multicellular bodies called thalli
Classification of Algae CONCEPT 12.11 Classified based on different features Differences in photosynthetic pigments Storage products Cell wall composition Various groups Division Chlorophyta Kingdom Rhodophyta Phaeophyta Chrysophyta FACT 12.18
Division Chlorophyta (green algae) FACT 12.19 Most are unicellular and filamentous Spirogyra Cell wall - cellulose Kingdom Rhodophyta (red algae) Cell wall - Agar unicellular red algae Thermoacidophilic found in Yellowstone geysers
Phaeophyta (brown algae) FACT 12.20 Cell walls composed of cellulose and alginic acid Alginic acid is used medically and as a thickening agent
Chrysophyta (golden algae, yellow-green algae, and diatoms) FACT 12.21 Most are marine algae - phytoplankton Diatoms silica frustules Cell wall cellulose and silica
Water Molds CONCEPT 12.12 Differ from fungi in several ways Have tubular cristae in their mitochondria Cell walls are of cellulose instead of chitin Decompose dead animals and return nutrients to the environment Recyclers in Water FACT 12.22 Some species are pathogens of crops caused the Irish potato famine
Other Eukaryotes of Microbiological Interest: Parasitic Helminths Parasitic worms have microscopic infective and diagnostic stages
CONCEPT 12.13 FACT 12.23 Other Eukaryotes of Microbiological Interest: Vectors Arthropod vectors are animals that carry pathogens 1) Arachnids (Adult have four pairs of legs) Ticks are the most important arachnid vectors 2) Insects (Adult have three pairs of legs and three body regions) Include Fleas, Lice, Flies and Mosquitoes (most important)