Plasmodium falciparum...
the parasite that never gives up

 

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Eaten Alive!
Nutrition of a Parasite
As mentioned earlier, P. falciparum is a parasite that obtains the bulk of its nutrition from its host. During the assexual phase of reproduction, the host is always a human. During the sexual phase, a female Anopheles mosquito is the host. Once the species has found its host most of the hard work is done, and few things stand in its way.

Main consumption of nutrients begins when a single merozoite is enclosed in a vacuole of the host's red blood cell, separate from the cytoplasm.


From here, three visible stages occur.

Stage Time Frame What is occuring
Ring StageImage found at: http://www.dpd.cdc.gov/DPDx/HTML/ImageLibrary/Malaria_il.htm approx. 24 hours metabolically characterless
 

Tropozite Stage

Image found at: http://www.dpd.cdc.gov/dpdx/HTML/Malaria.asp?body=Frames/M-R/Malaria/falciparum/body_Malariadffalctrop.htm

 

 between 6-12 hours Very active - most of the red blood cell's cytoplasm is consumed during this period
 

Schizont Stage

Image found at: http://www.dpd.cdc.gov/dpdx/HTML/Malaria.asp?body=Frames/M-R/Malaria/falciparum/body_Malariadffalctrop.htm

 

 between 12-18 hours 4-5 rounds of binary fissions occur, the added merozoites that will later burst from the cell and start another round.

 Entire process takes about 48 hours and is closely linked to reproduction

P. falciparum contains a cytostome which is a large double membrane structure that connects the parasite and red blood cell's cytoplasm. When the cytostomes devour a red blood cell's cytoplasm another vesicle is formed by budding. The newly formed vacuole becomes the site of most hemoglobin digestion. Enzymes are present to aid in the digestion, and dense hemozoin crystals aid in differential centrifugation. Because of these enzymes and other processes occurring, the digestive vacuole must be maintained at a specific pH (around 5.0) and ionic strength (Francis) (Ralph).

P. falciparum uses glucose and glycerol as its major source of carbon (Gardner). The cytoplasm of the red blood cells contains 95% hemoglobin. The hemoglobin is then used to generate amino acids for the parasite. This is considered highly important because P. falciparum lacks the capability to synthesize many amino acids itself. Amino acids that are not present or present in small amounts in the cytoplasm (methionine, cysteine, glutamine, glutamate, and isoleucine) are found in the human cell medium. The hemoglobin and cytoplasm catabolism is then used for protein synthesis. A secretory pathway that aids in protein transport is available (Gardner).

Energy production is done through anaerobic glycolysis, where the parasite converts pyruvate to lactate (Gardner).

Much of how falciparum transports and metabolizes the food it ingests still questionable or more in-depth than what will be explored here. For closer look  CLICK HERE


One of the leading tools for understanding P. falciparum and how it maintains life is its gene sequence and family tree.