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Eukaryotes and Viruses Chapters 12 and 13. Fungi Heterotrophic, Mainly Opportunistic Pathogens.

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Presentation on theme: "Eukaryotes and Viruses Chapters 12 and 13. Fungi Heterotrophic, Mainly Opportunistic Pathogens."— Presentation transcript:

1 Eukaryotes and Viruses Chapters 12 and 13

2 Fungi Heterotrophic, Mainly Opportunistic Pathogens

3 Distinguishing Characteristics of Fungi Chemoheterotrophic Cells walls composed of Chitin Diverse Metabolic Capabilities for Complex Carbohydrates Xerophilic Aerobic/Facultative Anaerobes Prefer Low pH

4 Vegetative Growth Filamentous Fungi Yeasts Dimorphic Fungi

5 Filamentous Fungi Hyphae (individual strands) –Septate –Coenocytic Mycelium (mass of hyphae) Aerial Hyphae Mass of Conidia

6 Yeast Bud Bud Scar Pseudohyphae

7 Dimorphic Fungi Medically very important Hyphae in the Environment, Yeast in the host Temperature and CO 2 are common triggers

8 Fungal Lifecycle Haplodiplontic Lifecycles Asexual Cycle Sexual Cycle

9 Haplodiplontic Life Cycle Gametophyte (n) Sporophyte (2n) Egg Sperm Zygote Embryo Sporangia Sporocyte Spores Haploid Diploid

10 Asexual Spores Genetically Identical to the parent Genetically Haploid Several Types –Conidia –Blastoconidia –Arthroconidia –Chlamydoconidia –Sporangiospores

11 Sexual Spores Haploid Spores Arising from a Diploid Cell Genetic Recombination of compatible mating types Fungi are classified on the basis of their sexual cycles.

12 Medically Important Phyla Zygomycota Ascomycota Basidiomycota Deuteromycota (Asexual Fungi)

13 Zygomycota Coenocytic Hyphae Not a phylogentically distinct group. Sporoangiospores and Zygospores Rhizopus is a common genus.

14 Ascomycota Septate Hyphae and Yeasts Largest group of classified fungi Most Deuteromycota are classified in this group by Genetics Ascospores (in an ascus) and Conidia

15 Basidiomycota Septate Hyphae Basidiospores produced on Basidium, some produce conidia (though this is crude terminology)

16 Deuteromycota Depreciated, though still used Taxon Holding Phyla with no observed sexual state Most have been reclassified as Ascomycota based on Genetics Leads to confusion over nomenclature –Telomorph : Sexual State (preferred name) –Anamorph : Asexual State (common name)

17 Fungal Disease Mycoses are not common but difficult to treat. Mycoses are defined by the depth of tissue affected. Most fungi are either superficial or opportunistic pathogens… though overt pathogens exist.

18 Examples of Fungal Disease

19 Protozoa Diverse Unicellular Eukarya Pathogens

20 Protozoans Phylogenetically, a diverse and ill-defined group. Medically we are worried about the heterotrophs, not the photosynthetic phyla Complex lifecycles with unique stages –Trophozoite –Schizogony –Cyst

21 Protists Are NOT Monophyletic

22 Archaezoa Lack Mitochondria, but possess relics called mitosomes. Move by means of Flagella Possess two nuclei. Giardia intestinalis

23 Microspora No mitochondria No microtubules Obligate intra- cellular pathogens Common in AIDS

24 Amoebozoa Phylogenetically these organisms are not linked to a definite clade. Movement through pseudopods

25 Apicomplexa Named for the Apical complex, an organelle used for cell penetration. Complex Lifecycles with both a definitive and intermediate host

26 Plasmodium species

27 Eugelnozoa Hemoflagellates, more appropriately called Kinetoplastids, are the pathogenic members. Possess unique single mitochondrion called kinetoplasts. Many are Parasitic

28 Helminths The Worms

29 Characteristics of Pathogens They may lack a digestive system They have a reduced nervous system Lacking or atrophied movement systems Complex reproductive systems May be dioecious or monoecious

30 Platyhelminthes Flatworms, so called for overall flat body plan. Actually the Subphylum Neodermata All have a Neodermis (also called a cuticle) to protect them from the host and lack adaptations such as eyepores (found in free-living flatworms)

31 Trematodes Flukes Ventral and Oral Sucker to attach to host tissue. Life Cycles involve more than a single host and mutiple developmental stages

32 Schistosoma Life Cycle

33 Cestodes Tapeworms Three body sections, scolex, neck and proglottids No digestive system Mature proglottids are released through feces of host.

34 Phylum Nematoda Roundworms, due to the circular body cross-section. Not to be confused with Phylum Annileda, the segmented worms (i.e. Earthworms) Complete digestive systems Sexually dimorphic Numerous through out the environment

35 Comparative Anatomy

36 Nematoda Diseases

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