The Aconoidasida are a
class
Class, Classes, or The Class may refer to:
Common uses not otherwise categorized
* Class (biology), a taxonomic rank
* Class (knowledge representation), a collection of individuals or objects
* Class (philosophy), an analytical concept used d ...
of
apicomplexa
The Apicomplexa (also called Apicomplexia; single: apicomplexan) are organisms of a large phylum of mainly parasitic alveolates. Most possess a unique form of organelle structure that comprises a type of non-photosynthetic plastid called an ap ...
n
parasites
Parasitism is a close relationship between species, where one organism, the parasite, lives (at least some of the time) on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The en ...
coined by Mehlhorn ''et al'' in 1980.
Description
Organisms in this class bear a tip at one end of their outer membrane. This apical complex includes vesicles called
rhoptries and
microneme
Micronemes are secretory organelles, possessed by parasitic apicomplexans. Micronemes are located on the apical third of the protozoan body. They are surrounded by a typical unit membrane. On electron microscopy they have an electron-dense ma ...
s, which open at the anterior of the cell. These secrete enzymes that allow the parasite to enter other cells. The tip is surrounded by a band of
microtubule
Microtubules are polymers of tubulin that form part of the cytoskeleton and provide structure and shape to eukaryotic cells. Microtubules can be as long as 50 micrometres, as wide as 23 to 27 nanometer, nm and have an inner diameter bet ...
s, called the polar ring.
As the name indicates, Aconoidasida (from
Greek
Greek may refer to:
Anything of, from, or related to Greece, a country in Southern Europe:
*Greeks, an ethnic group
*Greek language, a branch of the Indo-European language family
**Proto-Greek language, the assumed last common ancestor of all kno ...
: negative prefix ''a-'' = "lacking") lack a
conoid (they do have one only during the
ookinete stage) in contrast to the class
Conoidasida which have one throughout their life cycle.
See also
*
Haemosporidiasina
References
Apicomplexa classes
{{Apicomplexa-stub