Vl 8 - Parasite Organelles

Question 1

how does the number of micronemes and rhoptries differ in toxo and plasmodium stages?

Answer 1

• Toxo tachyzoites: 12 Rhoptries, abundant micronemes
• Plasmodium merozoite: 2 rhoptries, few micronemes
• Plasmodium ookinete: no rhoptry, abundant micronemes
• Plasmodium sporozoite: 2-4 rhoptries, abundant micronemes

Question 2

Which metabolite are synthesized in the apicoplast? how can they be inhibited?he

Answer 2

• Isoprenoid biosynthesis (Precursors of vitamins and membrane anchors ) ⇒ Fosmidomycin
• Fatty acid biosynthesis ⇒ Triclosan
• Shikimate biosynthesis (Precursors of aromatic amino acids) ⇒ Glyphosate

Question 3

How was the apicoplast aquired?

Answer 3

• secondary endocytosis of an algae (which already endocytosed an ancient cyanobacterium)
• endosymbiontic gene transfer ⇒ then loss of symbiont nucleus and mitochondria (and photosynthetic ability)

Question 4

Why is the digestive vacuole important for plasmodium and how can it be targeted?

Answer 4

• location of heme detoxification (by crystallizing it to hemozoin)
• Chloroquine inhibits heme detoxification

Question 5

Which biosynthetic pathways happen in plasmids?

Answer 5

• tetrapyrrole synthesis
• heme synthesis
• chlorphyll synthesis

Question 6

What are mitochondrium derived organelles (MDOs)?

Answer 6

• Organelles which derived from mitochondria that were capable of anaerobic ATP production

MDOs:

• Hydrogenosome (Trichomonas)
• Mitosome (Giardia)