Eukaryotic Microbial Diversity Overview of taxonomy - PowerPoint PPT Presentation

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Eukaryotic Microbial Diversity Overview of taxonomy

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Carl Woese's work on rRNA. Three Domains: Archaebacteria, Eubacteria, and Eukaryotes ... new schemes, Protista split into 7 kingdoms, they are that different from one ... – PowerPoint PPT presentation

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Title: Eukaryotic Microbial Diversity Overview of taxonomy


1
Eukaryotic Microbial DiversityOverview of
taxonomy
  • Early attempts at taxonomy all plants and
    animals
  • Some still refer to bacteria as flora
  • Whitaker scheme (late 20th century)
  • Five kingdoms Monera (bacteria) and 4 eukaryotic
    kingdoms
  • Carl Woeses work on rRNA
  • Three Domains Archaebacteria, Eubacteria, and
    Eukaryotes
  • The four eukaryotic kngdoms
  • Animals, plants, fungi, and protists
  • Grouped by similar structure, physiology, and
    behavior
  • The boundaries of these kingdoms now being
    altered by research in molecular biology.

2
Eukaryotes vs. prokaryotes
  • Eukaryotes are larger
  • Eukaryotes have membrane-bound organelles
  • Nucleus, mitochondria, membrane systems
  • Larger size requires functional compartments
  • Mitochondria once bacteria? So same size!

http//www.earthlife.net/images/eury-cell.gif
3
Microbial eukaryotes
  • Animals
  • Parasitic worms studied by Parasitologists
  • Fungi
  • Yeasts and molds, studied by Mycologists
  • Several types can cause human disease
  • Protists
  • Unicellular eukaryotes with many different
    characteristics. Also studied by Parasitologists.
  • Some cause human disease
  • Plants not of particular interest other than
    hosts

4
Protista the grab bag Kingdom
  • Protists are generally microscopic, unicellular,
    eukaryotes.
  • Historically, classified together because of
    their differences from other organisms
  • Always recognized as a highly diverse group
  • Since the application of molecular biology,
    taxonomy of all things constantly changing.
  • In new schemes, Protista split into 7 kingdoms,
    they are that different from one another and from
    other organisms

5
Kingdom Protista
  • Highly diverse group of organisms
  • Size range from 5 ┬Ám to 5 mm
  • Defined more by what they arent
  • Nutrient/energy acquisition ranges from
    photosynthesis to predatory to detrivores
  • Important in many food webs
  • Provide link between bacteria and larger
    organisms
  • Learn simple, unofficial taxonomy

library.thinkquest.org/ 12413/protist.html
6
Plant-like Protists
  • Contain chloroplasts
  • Representatives
  • Diatoms (right).
  • Diatomaceous earth fossilized diatoms
    abrasives and slug repellants.
  • Red, brown, yellow algae
  • Seaweed, source of agar
  • Dinoflagellates
  • Neurotoxins and red tide

http//www.bhikku.net/archives/03/img/diatoms.JPG
www.enviroliteracy.org/ article.php/534.html
7
Fungus-like
  • Water molds
  • Motile spores, unlike true fungi
  • Phytophora infestans caused the great Irish
    potato blight and extensive emigration.
  • Slime molds
  • Cellular slime mold, individual amoebas that
    aggregate to form fruiting body
  • Plasmodial slime mold the blob. Similar life
    cycle.

http//en.wikipedia.org/wiki/Slime_mold
8
The Protozoa
  • Most medically important protists are protozoa
  • Unicellular eukaryotes
  • Lack a cell wall
  • Require moist environments (water, damp soil,
    etc)
  • Mostly Animal-like
  • Great amounts of diversity
  • Locomotion float, cilia, flagella, pseudopodia
  • Nutrition chemoheterotrophs, photoautotrophs,
    either
  • Simple to complex life cycles, reproduction
  • Different cell organelles, some lack mitochondria

9
Animal-like protists
  • Most likely to cause human disease
  • Typically have a complex life cycle
  • Esp. sporozoans, involving several stages and
    multiple hosts
  • Classified mostly according to type of motility
  • Amoebas (cytoplasmic streaming)
  • Ciliates (cilia)
  • Flagellates (flagella)
  • Sporozoans (non-motile)

http//ar.geocities.com/seti_argentina/estamos_sol
os/ameba.jpg
10
Amoebae
  • Amoebae move and feed using pseudopodia
  • Cytoskeleton aids extension of cell membrane,
    cytoplasmic streaming.
  • Some have loose shells some form cysts.
  • Fossilized shells major component in some
    limestones.
  • Protists with the structure of ameobae are
    classified in more than one group.
  • Most live in the environment, eating bacteria
  • Entamoeba, Naegleria examples of
    disease-causing amoebae.

11
Other Protozoa
  • Ciliates
  • move by cilia, short flagella-like appendages
  • Includes disease-causing Balantidium
  • Flagellates
  • Move using flagella
  • Some disease-causing flagellates include
  • Giardia, forms cysts, causes diarrhea
  • Trichomonas, inhabits vagina, potential STD
  • Sporozoans Generally have complex life cycles
  • Include Plasmodium (malaria), Toxoplasma
    (toxoplasmosis)

12
Fungi
  • Mycology the study of fungi
  • Fungi are mostly saprophytes, all heterotrophs
  • Saprophytes decay non-living organic matter
  • Fungi are the kings of decomposition
  • Heterotrophs use pre-formed organic matter
  • Not autotrophs, not photosynthetic
  • Fungi grow into, through their food
  • Release extracellular enzymes, break down
    polymers into LMW compounds for transport

13
Fungi terminology and structure
  • Hypha (singular) hyphae (plural) thread
  • Hyphae may be partially separated into cells or
    not at all (ceonocytic).
  • Cytoplasm is continuous throughout hypha
  • Mycelium (plural mycelia) a mass of hyphae
  • Like a bacterial colony except really all one
    organism.
  • Some fungi are molds, some are yeasts
  • Yeasts are oval, unicellular
  • Dimorphic able to grow as either form.
  • Typical of some disease-causing fungi

14
Impacts of Fungi
  • Disease mycosis (plural mycoses)
  • Superficial (on hairs, nails)
  • Cutaneous (dermatophytes, in skin (athletes
    foot)
  • Subcutaneous (deeper into skin)
  • Systemic (in deeper tissues, usually via lungs)
  • Opportunists serious disease when immune system
    is depressed.
  • Antibiotic production
  • Penicillium, Cephalosporium
  • Decomposition Food industry (soy sauce)

15
Classification of fungi
  • By sexual reproductive structures
  • Fungi reproduce both asexually and sexually
  • Deuteromycota Fungi Imperfecti
  • No longer a valid classification
  • Contained fungi that couldnt be coaxed into
    having sex
  • Through morphological and molecular means (e.g.
    DNA analysis), being distributed into the other 3
    phyla of fungi.

16
Classification-2
  • Zygomycota produce zygospores
  • Example Rhizopus
  • Fusion of hyphae (haploid) of opposite mating
    types produces zygospore (diploid).
  • Zygospore produces a zygosporangium with haploid
    spores that are released.
  • Asexually, sporangium containing spores.

sporangia
Zygospore
botit.botany.wisc.edu/ images/332/Zygomycota/Z...
www.butte.cc.ca.us/.../ fungi.unks.html
17
Classification-3
  • Ascomycota the sac fungi
  • Sexual spores produced inside an ascus (sac)
  • Asexual spores are called conidiospores or
    conidia (singular conidium)
  • Many types of common molds are ascomycetes.

Ascus
conidia
fungus.org.uk/ nwfg/ascus.htm
inseto.rc.unesp.br/.../ fungos20e20micoses.htm
www.ent.iastate.edu/.../ aspergillus_ear_rot.html
18
Classification-3
  • Basidiomycota the club fungi or mushrooms
  • After extensive growth of hyphae, opposite mating
    types fuse and above ground mushroom is formed.
  • Sexual spores are called basidiospores asexual
    conidia can also be formed.

Close-up of gills
www.birdsasart.com/ bn106.htm
www.fishing-in-wales.com/. ../fungi/parasol.htm
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