Table 1 Morphology of gametocytogenesis
From: Gametocytogenesis : the puberty of Plasmodium falciparum
| Â | Stage I | Stage II | Stage III | Stage IV | Stage V |
|---|---|---|---|---|---|
Shape (Light microscopy) [4,16, 18, 159] | IA: Indistinguishable from the small round trophozoite IB: Larger round shape, distinguished by granular distribution of pigment in food | IIA: elongates within the erythrocyte IIB: D shaped | D shaped, slightly distorted erythrocyte Pink/blue distinction of the male/female. | Elongated and thin parasite, distorted red cell Male: pigment tends to be scattered Female: pigment more dense | Sausage shaped parasite with rounded extremities Male: pigment scattered, pink Female: dense pigment, light violet (see Figure [1]) |
Ultrastructure [18] | -No visible alteration of the erythrocyte plasmalemma ("knobless"), opposite the knobbed asexual infected erythrocyte -Formation of a subpellicular membrane flattened vesicle and microtubule array -Sexual dimorphism in nuclear size | -Subpellicular membrane and microtubule complex in expansion (giving the D form) giving an asymmetrical cell -Nucleus in terminal site or elongated across the long axis of the cell; some spindle observed within it | -Further development of the subpellicular membrane complex distorts cell -Male nucleus is notably larger(also becoming lobbed) then that of the female, which contains slightly more ribosomes, ER and mitochondria then the male. | -Membrane and microtubule complex now surrounds the gametocyte completely (restoring symmetry) -Appearance of membrane bound osmophillic bodies -Obvious sexual dimorphism: mitochondria, ribosomes and osmophillic bodies more numerous in female, a transcription factory is observed; male nucleus is larger In male kinetochores of each chromosome are attached to an electron dense body, located over a nuclear pore, opposite of which there is a MTOC (cytoplasmic face of the pore) | -Loss of subpellicular microtubules by depolymerisation, the inner membrane remains -Microgametocyte (male) exhibit a dramatic reduction in ribosomal density, very few mitochondria, with a large nucleus with a kinetochore complex attached to the nuclear envelop -Numerous mitochondria, ribosomes and osmophillic bodies in the macrogametocyte (female); the nucleus is small with a transcription factory |
Time of appearance (days) [159] | 0–2 | 1–4 | 2–8 | 6–10 | 9–23 |
Point in the cell cycle [160] | G1 | G1 | G0 | G0 | G0 |