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Eukaryotes and Viruses

Eukaryotes and Viruses. Chapters 12 and 13. Fungi. Heterotrophic, Mainly Opportunistic Pathogens. Distinguishing Characteristics of Fungi. Chemoheterotrophic Cells walls composed of Chitin Diverse Metabolic Capabilities for Complex Carbohydrates Xerophilic Aerobic/Facultative Anaerobes

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Eukaryotes and Viruses

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  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 CO2 are common triggers

  8. Fungal Lifecycle • Haplodiplontic Lifecycles • Asexual Cycle • Sexual Cycle

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