Karyolysus
Karyolysus | |
---|---|
Scientific classification | |
Domain: | Eukaryota |
Clade: | Diaphoretickes |
Clade: | SAR |
Clade: | Alveolata |
Phylum: | Apicomplexa |
Class: | Conoidasida |
Order: | Eucoccidiorida |
Family: | Karyolysidae |
Genus: | Karyolysus |
Species | |
Karyolysus lacazei |
Karyolysus is a genus of coccidia.
History
The genus was created by Labbe in 1894 for those species of sporozoans that fragmented the host nucleus. Reichenow in 1921 established that this property was of dubious taxonomic value. He proposed a different set of criteria for inclusion in this genus and these are the one currently in use.
The type species is Karyolysus lacertae[2] .
Characteristics of the genus
Differentiation from the genus Haemogregarina may be difficult as in both genera gametocytogenesis occurs in the erythrocytes and have similar morphology. They can be distinguished on the location of schizogony: In Karyolysus this occurs in the endothelial cells of the visera while in Haemogregarina schizogony occurs in the bone marrow.
Life cycle
Starting with infected
On entering the blood stream the merozoites penetrate other endothelial cells. There they grow and undergo schizogeny producing a number of small merozoites. These second generation schizonts are smaller than the first generation and lack a discernable nucleus. These are also eventually released into the blood stream, this occurs usually day 42 post infection.
These small merozoites are actually gametocytes. These penetrate erythrocytes and differentiate into macrogametoctyes and microgametocytes. Both types are surrounded by a thin membrane. The microgametocytes remain thin and do not develop a nucleus. The macrogametocytes in contrast enlarge and develop a visible nucleus at one end of the nucleus[clarification needed].
On ingestion by a female mite (male mites do not require blood) the gametocytes are released from the erythrocytes. Within the gut they associate in spindle like pairs and enter the epithelial cells of the gut. Within the epithelial cell the macrogametocyte increases in size while the microgametocyte shrinks. The microgametocyte divides in two and one of the motile gametes so formed fuses with the macrogametocyte to form a zygote.
The zygote (or
On release from the oocyst the sporokinetes migrate throughout the body of the mite. Some settle in the ovaries and enter the
Taxonomy
A study of the 18s rRNA suggests that this genus may overlap with Hepatozoon.[3]
Host records
K. sonomae - yellow legged frog (
Hosts known to be infected but parasite species not reported
Lizard (Lacerta raddei nairensis)