Classification of Microbes

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Classification of Microbes
2013-09-12 01:59:05
Biology 106

Biology 106
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  1. microbes in our lives
    bacteria, fungi, protozoa, microscopic algae, and viruses
  2. pathogenic
    disease causing
  3. Group of 3 domains
    • Bacteria: Prokaryotic cells; cell walls made of peptidoglycan
    • Archea: Prokaryotic cells; if cell wall, lack peptidoglycan
    • Eukarya: Eukaryotic cells; protists, fungi, plants, animals
  4. bacteria

    what kind of organism?
    Cell wall?
    • Simple, unicellular organisms
    • Prokaryotic: genetic material not surrounded by membrane
    • Cell wall: made up of pepetidoglycan
    • Nutrition: organic chemicals, inorganic Chemicals, or photosynthesis
    • Movement: "swim" using flagella
    • Reproduction: binary fission
  5. archae

    what kind of organism?
    Cell wall?
    • simple, unicellular organisms
    • Prokaryotic cells: genetic material not surrounded by membrane
    • Cell wall: may or may not have; if they do, no peptidoglycan
    • Nutrition: organic chemcials, inorganic chemicals, or photosynthesis
    • Movement: "swim" using flagella
    • Reproduction: binary fission
    • found in extreme envrionment (high salt, high temperature, etc) and not known to cause disease
  6. Viruses

    What kind of microscope can see viruses?
    • can only be seen with electron microscope
    • Acellular: not cellular (therefore no "cell" wall); very simple structure
    • Reproduction: only inside host cell
  7. Normal Microbiota
    • also known as flora, microbes on and in our bodies
    • 1. Don't usually cause harm; often beneficial
    • Prevent over-growth; produce vitamins
    • 2. Cause harm if they leave normal habitat.
    • 3. Our resistance (the ability to ward off diseases) determines if microbes is harmful
    • Skin, chemicals produced by normal flora, stomach acid, white blood cells, fever, etc
  8. Infectious Diseases
    • 1. Pathogen invades susceptible host,
    • 2. Spends part of its life cycle in the host,
    • 3. Disease results from the microbe or it's products
    • End of WWII, thought to be "under control".
  9. Emerging Infectious Diseases: (EIDs)
    • new or changing diseases
    • 1. Factors contributing to EIDs:
    • Evolutionary changes in existing organisms
    • Modern transport: spread known diseases to new regions/ populations
    • Increased human exposure to new agents due to human spread and activities
    • 2. Example of EID:
    • Avian influenza A (H5N1) virus:
    • 2003: millions of poultry & 24 people in 8 countries
    • Subtype of Influenza A foundi n many animals; usually species specific
    • Sometimes cross over and cause illness
    • As of 2008: 242 people; 50% mortality
  10. Chemotroph
    organic/ inorganic molecules as energy source
  11. Phototroph
    light as energy source
  12. Heterotroph
    organic molecules as carbon source
  13. Chemoheterotroph
    organic/ inorganic molecules as energy source; organic molecules as carbon source
  14. mycology
    study of fungi
  15. mycosis
    fungal infection
  16. unicellular
    yeasts (single cell, eukaryotes)
  17. multicellular
    filamentous (molds), or fleshy (mushrooms)
  18. thallus (body)
    consists of long filaments of cells joined together; these filaments are called hyphae.
  19. Vegetative hyphae
    portion that obtains nutrients
  20. Aerial hyphae
    portion used for reproduction
  21. Harmful effects of fungi
    • fungal infections increasing due to increase in patients with compromised immune systems
    • more than $1 billion/ year in crop damage
  22. Beneficial of fungi
    • recycle vital elements
    • Make: foods (bread); drugs (penicillin)
  23. General description of fungi

    Cell wall?
    • Cell wall: chitin
    • Eukaryotic cells (genetic material is surrounded by a membrane)
    • Nutrition: chemoheterotrophs; decompose and absorb nurtirnets from environment
    • Reproduction: sexual or asexual
  24. Dimorphic Fungi
    • Two forms of growth: mold-like or yeast-like
    • Pathogenic species: yeast-like at 37'C, mold-like at 25'C
  25. Background of Algae

    Cell wall?
    • Cell wall: cellulose
    • Uni- or multicellular Eukaryotes
    • Nutrition: photoautotrophs; lack tissues of plants
    • Reproduction: sexual (meiosis) or asexual (mitosis)
    • Do not cause infections
    • Diseases result from toxins produced by algae.
  26. Protozoal and Helminth Hosts:
    • Stage of parasite development determines the host type:
    • intermediate host: harbors larval or asexual stage of the parasite
    • definitive host: harbors adult, sexuallymature parasite
    • Eukaryotic cysts: protective capsule; survival when conditions are not optimal; transmission
  27. Background of Protozoa

    Eukaryotic cells?
    Cell wall?
    • General description:
    • Eukaryotic cells
    • Unicellular
    • No cell wall
    • Nutrition: hetertrophs; free-living or parasites that ingest, photosynthesize, or absorb nutrients
    • Movement: pseudopods, flagella, or cilia
    • Reproduction: sexual or asexual
    • Live in animals, water, or soil
  28. Medically Important Protozoa:
    Superkingdom Excavata: Archaezoa:

    9 points
    • multiple flagella
    • Mitosome instead of mitochondria
    • Found in animal digestive tracts
    • Ex 1: Giardia lamblia:
    • Glardiasis: amoebic dysentery
    • Excreted in feces as cyst; ingested by next host.
    • Ex 2: Trichomonas vaginalis:
    • Urinary tract infections
    • Transmitted: towels, toilets, sexual contact
  29. Medically Important Protozoa:
    Superkingdom Excavata: Euglenozoa:

    2 points and 2 examples
    • Euglenoids (photoautotrophs) and Hemoflagellates (blood parasites)
    • Hemoflagellates transmitted by bites of insects feeding on blood; found in circulatory system
    • Ex 1: Trypanosoma: Chagas disease; transmitted by the "kissing bug"
    • Ex 2: T.brucei: African sleeping sickness; transmitted by tsetse fly
  30. Medically Important Protozoa:

    4 points and 2 examples
    • move by pseudopods
    • Ex 1: Entamoeba histolytica:
    • Intestinal pathogen; cysts excreted in feces, ingested by next host
    • Ex 2: Acanthamoeba:
    • Grows in water
    • Infect cornea; can cause blindess
  31. Medically Important Protozoa:

    4 points and 1 example
    • Obligate intracellular parasites
    • Organelles at cell apexes; contain enzymes to penetrate host tissues
    • Have complex life cycles; several hosts
    • Ex 1: Plasmodium sp: malaria
    • Definitive host Mosquito (Sporozoite) --> Intermediate host Human (Merozoite)
  32. Medically Important Protozoa:

    4 points and 1 example
    • movement and bring food to mouth
    • complex cells
    • Ex 1: Balantidium coli:
    • Dysentery
    • Only human parasite in this group
  33. Helminths: Parasitic Worms

    • A. Background:
    • 1. Multicellular eukaryotic animals; most possess digestive, circulatory, nervous, etc. systems.
    • 2. Parasitic (medically important) or free-living.
    • 3. Complex life-cycles:
    • may invovle multiple intermediate hosts for development of each larval stage
    • definitely host for adult parasite
  34. Kingdom: Animalia

    3 points
    • Phylum: Platyhelminthes (faltworms)
    • Classes: Trematodes (flukes) & Cestodes (tapeworms)
    • Phylum: Nematodes (roundworms)
  35. Trematodes (flukes)

    4 points
    • 1. flat, leaf-shaped bodies, with suckers.
    • 2. absorb food through their surface (cuticle)
    • 3. named according to tissue adult lives in: liver fluke, lung fluke, etc.
    • 4. humans as a definitive host
    • adult fluke release eggs in human lung --> eggs excreted in feces --> eggs reach water --> larvae hatches in water, infects intermediate host --> intermediate host eaten by human --> develops into adult
  36. Cestodes (tapeworms): intestinal parasites

    4 points
    • 1. Scolex (head) has suckers or hooks for attachment
    • 2. Absorb nutrients through cuticle
    • 3. Proglottids: segements; have male and female reproductive organs; in feces they are diagnostic of a tapeworm infection
    • 4. Humans as an intermediate hosts
    • adults tapeworm release eggs in definitive host --> eggs excreted by definitive host --> intermediate host (human) eats egg --> definitive host eats intermediate host --> matures into adult worm
  37. Nematodes (roundworms)

    7 points and 2 examples
    • 1. Completes digestive system; most have separate male and female worms
    • 2. Free-living in soil and water or parasites of plants and animals
    • 3. Human infections divided into two categories:
    • Eggs infective for humans:
    • - Ex. Pinworms
    • Pinworm eggs in soil --> eaten by humans --> become adult pinworms in large intestine
    • can be transmitted human to human by clothing or bedding
    • Larvae Infective for humans:
    • Ex. trichinella spiralis
    • trichinella larvae cysts in undercooked pork --> human eats pork --> trichinellosis
  38. Arthropods as vectors:

    3 points
    • 1. Animals with segemented bodies, external skeletons, and jointed legs
    • spiders, mites, ticks, flies, lice, etc.
    • 2. Vector: organism that carry pathogenic microbes
    • 3. Infection trough: mechanical transport or feeding