Question

Systemic fungal infections (e.g. Candida and Cryptococcus) and tuberculosis (Mycobacterium) are on the rise. One of the reasons these organisms have high virulence is that they fare better following macrophage phagocytosis than other microorganisms. Phagocytosis activates the glyoxylate cycle in fungi and mycobacteria, allowing them to use two-carbon substrates to sustain growth in an otherwise nutrient-poor environment of the phagolysosome.
a) Suggest some likely molecules that could be processed through the glyoxylate cycle in this circumstance.

b) What enzymes are unique for this cycle?

c) Does the glyoxylate cycle exist in animals? Why?

Answer 1

Answer:

a) the molecules can be found in the picture below

b) (i) isocitrate lyase ( isocitrate to glyoxylate)

   (ii) malate synthase (glyoxylate to malate)

c)  Glyoxylate cycle do no exist in animals

Explanation:

b) in the glyoxylate cycle isocitrate lyase helps in conversion of  isocitrate to glyoxylate. Also, helps in conversion of glyoxylate to malate by using malate synthase.

c)   Glyoxylate cycle do no exist in animals, it only exist in plants and bacteria. This is because they can produce glucose from acetyl-CoA in required amounts.They have the ability to change acetyl-CoA from fat into glucose. But in animals, this mechanism is not possible.