Asexual Spores Genetically Identical to the parent Genetically Haploid Several Types –Conidia –Blastoconidia –Arthroconidia –Chlamydoconidia –Sporangiospores
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.
Medically Important Phyla Zygomycota Ascomycota Basidiomycota Deuteromycota (Asexual Fungi)
Zygomycota Coenocytic Hyphae Not a phylogentically distinct group. Sporoangiospores and Zygospores Rhizopus is a common genus.
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
Basidiomycota Septate Hyphae Basidiospores produced on Basidium, some produce conidia (though this is crude terminology)
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)
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.
Examples of Fungal Disease
Protozoa Diverse Unicellular Eukarya Pathogens
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
Protists Are NOT Monophyletic
Archaezoa Lack Mitochondria, but possess relics called mitosomes. Move by means of Flagella Possess two nuclei. Giardia intestinalis
Microspora No mitochondria No microtubules Obligate intra- cellular pathogens Common in AIDS
Amoebozoa Phylogenetically these organisms are not linked to a definite clade. Movement through pseudopods
Apicomplexa Named for the Apical complex, an organelle used for cell penetration. Complex Lifecycles with both a definitive and intermediate host
Eugelnozoa Hemoflagellates, more appropriately called Kinetoplastids, are the pathogenic members. Possess unique single mitochondrion called kinetoplasts. Many are Parasitic
Helminths The Worms
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
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)
Trematodes Flukes Ventral and Oral Sucker to attach to host tissue. Life Cycles involve more than a single host and mutiple developmental stages
Schistosoma Life Cycle
Cestodes Tapeworms Three body sections, scolex, neck and proglottids No digestive system Mature proglottids are released through feces of host.
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