21 - intro to apicomplexans + plasmodium

phylum apicomplexa characteristics

1. obligate intracellular parasites

2. complex life cycles

3. apical complex

4. apicoplast

phylum apicomplexa

• apical complex

a. rhoptries + micronemes

• secretory organelles penetrating host cells

b. conoid + polar rings

• structural

phylum apicomplexa

• apicoplast

unique organelle

evolved from chloroplast

• function = fatty acid + AA synthesis

• exposure to disabling chem = killed or unable to penetrate host cell

• no equivalent in animal host cell

1° endosymbiosis

algal cell ancestor (euk) englufs cyanobacterium (prok) → algal cell w/ chloroplast (euk)

2° endosymbiosis

algal cell w/ chloroplast (euk) englufed by ancestral protist (prok)

→ apicomplexan w/ apicoplast

plasmodium characterisitics

malaria

swamps + fever

½ world pop @ risk

4 primary spp

plasmodium 4 primary spp

1. plasmodium vivax

2. p. ovale

3. p. malariae

4. p. falciparum

plasmodium life cycle steps 1-4

1. mosquito takes blood

2. infected liver cell

3. schizont

4. ruptured schizont

plasmodium steps 5-8

5. immature trophozoite

6. mature trophozoite

7. schizont

8. ruptured schizont

OR

5. immature

6. gametocytes

7. mosquito takes blood

plasmodium steps 9-12 from mosquito taking blood

9. microgamete enters macrogamete

10. ookinete

11. oocyst

12. ruptured oocyst

plasmodium vertebrae phase

• infected female Anopheles sp

mosquito takes blood

• probes skin for capillary

• injects salivary gland secretions (prevents clotting, sporozoites injected)

plasmodium vertebrae phase

• exoerythrocytic cycle steps

1. metamorpheses into trophozoite

2. schizogony (asexual repro) = cryptozoite makes multiple merozoites

3. merozoites burst out of hepatocytes

plasmodium vertebrae phase

• erytrhocytic cycle stages - 1. invasion of RBC

1. merozoite surface protein binds to protein on RBC surface

2. orients apical end to RBC

3. secretions from apical complex → activate invasion

4. parasitophorus vacuole

plasmodium vertebrae phase

• erythrocytic cycle - 4. schizogony

1. nuclear division → blood schizont

2. cytoplasmic division → merozoites develop

plasmodium vertebrae phase

• erythrocytic cycle - 5. mature merozoites

host cell ruptures → releases merozoites + metabolic wastes

invade other RBCs → several generations

plasmodium vertebrae phase

• erythrocytic cycle - synchrony = merozoites develop @ same time

synchronous release from host cells

• massive release of merozoites + toxic waste materials

  • host immune response

    • fever + chills

plasmodium vertebrae phase

• erythrocytic cycle - gametogony

some merozoites enter RBCs + develop into macrogametocytes or microgametocytes

plasmodium vertebrae phase

• erythrocytic cycle steps

1. invasion of RBC

2. transforms into trophozoite

3. trophozoite grows

4. schizogony

5. mature merozoites

6. synchrony

7. gametogony

plasmodium invertebrae phase steps

1. gametocytes released from RBC

2. microgamete fertilizes macro = sexual

3. ookinete

4. transforms into oocyst

5. sporozoites break out of oocyst

6. injected into next host during bloodmeal

plasmodium invertebrae phase steps

3. ookinete

mobile

penetrates stomach wall

attaches to hemocoel side

plasmodium invertebrae phase steps

5. sprozoites break out of oocyst

migrate → salivary gland

plasmodium invertebrae phase steps

6. injected into next host

increased change of transmission = PITT