Eukaryotic Microbes: Protists Flashcards
What is the main characteristic feature of Euglenozoans we examined and what are the two groups?
- they are flagellated (characteristic feature is a crystalline rod in flagellum- nobody knows why haha)
- Two major groups: Kinetoplastids and Euglenids
Euglenozoans:
- Describe Kinetoplastids?
- contain kinetoplasts ( mass of DNA in a single large mitochondrion)
- most important genus for humans is Trypanosoma
Euglenozoans:
- Describe Euglenids
- Facultatively phototrophic
- lose chloroplast and survive by heterotrophy in the dark
What are the shared characteristics of Diplomonads and Parabasalids?
- they probably have an early branching lineage
- flagellated and live in anaerobic environments
- Amitochondriate (lack mitochondria)
Describe the characteristics of Diplomonads
- two nuclei
- mitosomes (double membrane sacs without electron transport chain)
- most important for humans = Giardia intestinalis
Describe the characteristics of Parabasalids
- parabasal body(supports golgi) and hydrogenosomes
- live in body tracts ( GI and GU)
- most important for us is Trichomonas vaginalis
- sometimes the trichomonad is buried in cellular debris and only the violent motion of the flagella can be seen
Describe the main characteristic of Alveolates and what are the important groups.
- characterised by cortical alveoli -> f(x) is unknown: osmoregulation, secretion?
- Three groups: Ciliates, dinoflagellates and apicomplexans
Alveolates:
1. Ciliates
L> Describe this group
- all produce cilia, used for motility and often for feeding (ex Paramecium)
- have macro and micro nucleus
- anaerobic fermenters in the gut
Alveolates:
2. Dinoflagellates
L> Describe this group
- two flagella (obvious) which drive whirling motion
- aquatic and can be toxic (red tides) and bioluminescent
Alveolates:
3. Apicomplexans
L> Describe this group
- all are obligate animal parasites
- contain degenerate chloroplasts called APICOPLASTS - thought to originate from red alga
- include major human pathogens Plasmodium, Toxoplasma
Explain the main characteristic of the protist group Stramenopiles and what it’s major groups are.
- based on hairy flagella
- Groups=
1. Brown Algae (multicellular)
2. Golden Algae
3. Diatoms ( silica cell wall)
4. Oomycetes
Stramenopiles:
- Oomycetes
L> describe this group
*What causes potato blight?
- previously thought to be fungi (via filamentous growth, multinucleate hyphae)
- BUT BUT BUT
- cell wall is cellulose
- they are flagellated
- diploid phase is DOMINANT
- Phytophthora infestans causes potato blight
Describe the problems with eukaryotic phylogeny!
- rRNA sequencing gives ancient origin for simple eukaryotes (microsporidia, diplomonads etc)
- BUT these are secondairly simplified because of the loss of mitochondria
- THEREFORE the most likely scenario is an early diversification
- The final phylogeny is therefore unresolved - lol great
Describe Cercozoans and Radiolarians
- unifying feature??
- unifying feature is threadlike PSEUDOPODIAL movement (note that amoebozoa do this too)
- some are secondarily phototrophic (chlorarachniophytes)
- but most are heterotrophs that produce a shell called a TEST
Describe Amoebozoa
- use pseudopodial movement but via bigger (lobe like) protrusions
- diverse group, important (to us) for two reasons:
L> Pathogens (ex Entamoeba)
L> as cell biology models (Dictyostelium)
