The Aconoidasida are a
class
Class 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 differentl ...
of
apicomplexa
The Apicomplexa (also called Apicomplexia) are a large phylum of parasitic alveolates. Most of them possess a unique form of organelle that comprises a type of non-photosynthetic plastid called an apicoplast, and an apical complex structure. Th ...
n parasites created 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 matrix ...
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
microtubules, called the polar ring.
As the name indicates, Aconoidasida (from
Greek
Greek may refer to:
Greece
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 ...
: negative prefix ''a-'' = "lacking") lack a
conoid
In geometry a conoid () is a ruled surface, whose rulings (lines) fulfill the additional conditions:
:(1) All rulings are parallel to a plane, the '' directrix plane''.
:(2) All rulings intersect a fixed line, the ''axis''.
The conoid is a ri ...
(they do have one only during the
ookinete
Apicomplexans, a group of intracellular parasites, have life cycle stages that allow them to survive the wide variety of environments they are exposed to during their complex life cycle. Each stage in the life cycle of an apicomplexan organism i ...
stage) in contrast to the class
Conoidasida
Conoidasida is a class of parasitic alveolates in the phylum Apicomplexa. The class was defined in 1988 by Levine and contains two subclasses – the coccidia and the gregarines. All members of this class have a complete, hollow, truncat ...
which have one throughout their life cycle.
See also
*
Haemosporidiasina
Haemosporidiasina (Haemosporidia) is a subclass of apicomplexans described by Jacques Euzéby in 1988.Euzéby, J. (1988) Comparative Medical Protozoology, Vol. 3: Apicomplexa, 2: Haemosporidioses, Part 1: Plasmodiids, Haemoproteids, "Piroplasms" ...
References
Alveolata classes
{{Apicomplexa-stub