Protozoa (Protists) & Pluricellular Myxozoa Flashcards

- Classification/systematics - terminology - key characteristics - reproduction - life cycles

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1
Q

Kingdom Protozoa/Protista

A
  • Phylum Mastigophora (flagellates)
  • Phylum Apicomplexa
  • Phylum Ciliophora (ciliates)
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2
Q

Kingdom Animalia

A
  • Phylum Cnidaria (Myxozoa)
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3
Q

Phylum Mastigophora

A

flagellates

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4
Q

Phylum Ciliophora

A

ciliates

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5
Q

Phylum Cnidaria

A

Myxozoa

  • parasitic jellyfish
  • obligate parasite
  • has 2 host life cycle that has 2 different spore forms produced
  • have polar capsules
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6
Q

Protozoa

A
  • classified by locomotion
  • unicellular
  • eukaryotic
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7
Q

Microspora

A
  • not protozoans!

- sister to fungi

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8
Q

What do Apicomplexa and Ciliophora have in common?

A

Both are Alveolates under Subkingdom Protozoa

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9
Q

Phylum Euglenozoa

A
  • Excavates
  • include diplomonads & kinetoplasts
  • unicellular organisms in domain Eukaryota
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10
Q

diplomonads

A
  • parasitic flagellates
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11
Q

Amoebozoa

A
  • protists with pseudopods
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12
Q

Stramenopiles

A
  • Heterokonts (algae)

- Oomycetes (water molds)

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13
Q

Unikonts

A
  • amoebozoa

- opisthokonts (fungi & animals)

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14
Q

Excavates

A
  • amitochondriate flagellates
  • amoeboflagellates
  • Euglenozoa
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15
Q

Alveolates

A
  • ciliates
  • apicomplexans
  • dinoflagellates
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16
Q

Cercozoa

A
  • amoeboids & flagellates

- feed by means of pilose pseudopods

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17
Q

Protozoa

A
  • single-celled eukaryotes
  • free-living or parasitic
  • “first and animal-like” implies kinship with animal (metazoans)
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18
Q

protist

A
  • eukaryotic organism that has cells with nuclei and is not animal, plant or fungi
  • includes algae, slime molds and dinoflagellates
  • high-level classification of eukaryotic microorganisms
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19
Q

Zoite

A
  • little creature

- prefixes added to spite to denote a portion of the life history

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20
Q

sporozoite

A

infective form

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21
Q

trophozoite

A

form which feeds and grows

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22
Q

tachyzoite

A

form which divides rapidly

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23
Q

bradyzoite

A

form which divides slowly

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24
Q

merozoite

A

many

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25
Q

protozoa (protists)

A
  • unicellular, eukaryotic ‘animals’
  • nucleus, ER, mitochondria, Golgi body, lysosomes
  • anaerobic or aerobic
  • absorbs nutrients or have a ‘pseudo-mouth’
  • feeds on bacteria, other protozoa, organic matter or tissues of host
26
Q

key characteristics of protozoa

A
  • many are part of normal microbiota
  • do not cause disease
  • locomotion via pseudopodia, flagella, gliding movements or cilia
  • asexual repro = large exposure = large damage
  • hosts
    • host specific or broad spectrum
    • zoonotic aka non-host specific
  • chronic infections; immunity
  • forms cysts
27
Q

Protozoa - Asexual Reproduction

A
  • binary fission, budding, schizogony/multiple fission (merogony)
  • asexual repro = short generation time & quick turn-around
28
Q

Schizogony (merogony)

A
  • exponential increase in numbers
  • destruction of host cells in proportion to infection
  • stops after a fixed number of repetitions
29
Q

Protozoa - Binary Fission

A
  • most common form of repro in prokaryotes
  • also occurs in some single-celled eukaryotes
    • e.g. ciliate Paramecium
30
Q

Protozoa - Schizogony (Merogony)

A
  • characterized by multiple divisions of nucleus and cell
  • common in many apicomplexans
    • e.g. Merocystis kathae In scallops (very pathogenic)
31
Q

Intermediate host

A
  • part of asexual reproduction life cycle
    • e.g. Merocystis kathae in scallops
  • scallops are intermediate hosts
32
Q

Protozoa - Sexual Reproduction

A
  • gametogeny or sporogony
  • merozoite becomes a macrogametoyte (macrogamont) and then a macrogamete or micro gametocyte (microgamont) and then several microgametes
  • microgamete fertilizes a macrogamete -> zygote
    • a wall forms around zygote -> becomes an oocyst
  • definitive host: Merocystis kathae in common whelk (sea snail) (not pathogenic)
33
Q

Definitive host

A
  • part of sexual reproduction life cycle
    • e.g. Merocystis kathae in common whelk (sea snail)
  • sea snails not harmed
  • not pathogenic
34
Q

Protozoa - flagellates

A
  • subphylum: Mastigophora
  • locomotion: by pseudopodia and/or flagella
  • order: Kinetoplastorida and Diplomonadorida/Trichomonadorida
35
Q

Kinetoplastorida

A
  • haemoflagellates
  • parasites of the blood
  • generally transmitted by biting insects
  • e.g. Trypanosoma cruzi
36
Q

Diplomonadorida/Trichomonadorida

A
  • flagellates
  • predominantly of the intestines
  • e.g. Giardia, Spironucleus, histomonas, tritrichomonas
37
Q

Protozoa - Ciliates

A
  • Phylum: Ciliophora
  • locomotion: by cilia
  • e.g. Balantidium sp. (pathogenic)
38
Q

Balantidium coli

A
  • parasitic species of ciliate (alveolate)
  • only member of ciliate phylum known to be pathogenic to humans
  • also found in pigs and other mammals aka zoonotic
    • asymptomatic in pigs
  • transmission: contaminated water
39
Q

Protozoa - Apicomplexa

A
  • Phylum: Apicomplexa
  • locomotion: gliding
  • life cycle: largely intracellular
  • sexual and asexual phases
  • Order: Eucoccidiorida, Piroplasmorida, Haemosporida
40
Q

Eucoccidiorida

A
  • parasite of epithelial cells
  • sexual and asexual repro occurs in epithelial cells
  • e.g. Eimeria/Goussia, Isospora, Cystoisospora, Hepatozoon, Sarcocystis, Cryptosporidium, Neospora, Toxoplasma
  • diagnostic stage for final host can be small
  • asexual stage causes damage
  • cyst stage (oocyst)
    • oocyst: ‘the diagnostic feature’
41
Q

Piroplasmorida

A
  • parasites of blood cells
  • vectors: ticks
  • sexual repro occurs in ticks
  • asexual repro in host animal
  • e.g. Babes, Theileria
42
Q

Haemosporida

A
  • parasites of blood cells
  • vectors: biting insects
  • sexual repro occurs in insects
  • e.g. Plasmodium (malaria)
43
Q

Goussia oocysts

A
  • 4 sporocysts each with 2 sporozoites

- release of sporozoites from sporocysts is via longitudinal suture

44
Q

Eimeria oocysts

A
  • 4 sporocysts each with 2 sporozoites

- release of sporozoites from sporocysts is via Stieda body at apex of sporocyst

45
Q

Epieimeria sp.

A
  • epicellular development
46
Q

Crystallospora sp.

A
  • sporocysts with a regular crystalline appearance
47
Q

Apicomplexa - one host

A
  • many Eimeria and Goussia spp. sporulate outside of host
48
Q

Apicomplexa - 2 hosts

A
  • e.g. Sarcocystis spp.
49
Q

Toxoplasma gondii

A
  • Apicomplexa
  • obligate intracellular, parasitic alveolate
  • causes toxoplasmosis
50
Q

cyst form

A
  • for survival
51
Q

Myxozoa

A
  • parasitic jellyfish (Cnidaria)

- have 2 host life cycle (obligate parasites)

52
Q

polar capsule/filaments

A
  • used in sporoplasm release

- evolved/derived nematocyst

53
Q

Myxozoan polar capsules are nematocyst-like structures -> shared ancestral feature. T/F?

A

True

54
Q

Myxobolus cerebralis

A
  • characteristic erratic tail chasing behavior (whirling disease)
  • blackened caudal area due to damage of CNS
55
Q

actinospore

A

?

56
Q

myxospore

A
  • defining diagnostic feature for myxosporea infections
57
Q

histozoic

A
  • develop inside muscle tissues (skeletal muscle) and other organs
  • pathogenic
58
Q

coelozoic

A
  • develop inside coelom-like spaces
    • e.g. the gallbladder
  • not pathogenic
59
Q

Why are we interested in the Myxozoa?

A
  • used to help monitor host populations

- serve as biological tags

60
Q

biological tags (BTs)

A
  • living biological markers, usually parasites, that can be used to indicate changes/movements in certain systems or populations.
61
Q

desirable properties of a parasite for use as a biological tag

A
  • easily detected and identified (microscopy & PCR)

- do not cause serious damage/pathology to host

62
Q

polar capsules

A
  • used to help infect a new host

- related to the stinging cells (nematocysts) in non-parasitic cnidaria