Search results
Results From The WOW.Com Content Network
The cyst wall of some ciliated protists is composed of four layers, ectocyst, mesocyst, endocyst, and the granular layer. The ectocyst is the outer layer and contains a plug-like structure through which the vegetative cell reemerges during excystation. Interior to the ectocyst, the thick mesocyst is compact yet stratified in density.
A sporozoite (ancient Greek sporos, seed + zōon, animal) is the cell form that infects new hosts.In Plasmodium, for instance, the sporozoites are cells that develop in the mosquito's salivary glands, leave the mosquito during a blood meal, and enter liver cells (hepatocytes), where they multiply.
Parasitology is the study of parasites, their hosts, and the relationship between them. As a biological discipline , the scope of parasitology is not determined by the organism or environment in question but by their way of life.
In all species, four or more sporozoites (depending on the species), equipped with an apical complex, escape from the oocysts in a process called excystation. They find their way to the appropriate body cavity, and penetrate host cells in their immediate environment.
Phoronts go through metamorphosis to prepare for excystation. Metamorphosis changes the body shape, organization, and physiology of the phoront to allow for rapid ingestion and storage of large amounts of food. Histotrophic phoronts metamorphose within a few hours of encysting on their hosts.
Once ingested, the cyst travels through the digestive system unaffected until it reaches the small intestine, where it encounters several triggers, that have been found to induce excystation. Such triggers include, low glucose, [ 10 ] osmotic shock, [ 1 ] and a combination of water, bicarbonate, and bile. [ 11 ]
A trophozoite (G. trope, nourishment + zoon, animal) is the activated, feeding stage in the life cycle of certain protozoa such as malaria-causing Plasmodium falciparum and those of the Giardia group. [1]
Entamoeba coli is a non-pathogenic species of Entamoeba that frequently exists as a commensal parasite in the human gastrointestinal tract. E. coli (not to be confused with the bacterium Escherichia coli) is important in medicine because it can be confused during microscopic examination of stained stool specimens with the pathogenic Entamoeba histolytica. [1]