Eukaryotic Microbes: Protists Flashcards Preview

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Flashcards in Eukaryotic Microbes: Protists Deck (16):
1

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

2

Euglenozoans:
- Describe Kinetoplastids?

- contain kinetoplasts ( mass of DNA in a single large mitochondrion)
- most important genus for humans is Trypanosoma

3

Euglenozoans:
- Describe Euglenids

- Facultatively phototrophic
- lose chloroplast and survive by heterotrophy in the dark

4

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)

5

Describe the characteristics of Diplomonads

- two nuclei
- mitosomes (double membrane sacs without electron transport chain)
- most important for humans = Giardia intestinalis

6

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

7

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

8

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

9

Alveolates:
2. Dinoflagellates
L> Describe this group

- two flagella (obvious) which drive whirling motion
- aquatic and can be toxic (red tides) and bioluminescent

10

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

11

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

12

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

13

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

14

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

15

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)

16

What are the five main protist phyla?

1. Cercozoans
2. Stramenopiles
3. Alveolates
4. Euglenozoa
5. Amoebozoa