Acanthamoebidae is a family of single-celled

eukaryote The eukaryotes ( ) constitute the Domain (biology), domain of Eukaryota or Eukarya, organisms whose Cell (biology), cells have a membrane-bound cell nucleus, nucleus. All animals, plants, Fungus, fungi, seaweeds, and many unicellular organisms ...

s within the group

Amoebozoa Amoebozoa is a major Taxonomy (biology), taxonomic group containing about 2,400 described species of Amoeba, amoeboid protists, often possessing blunt, fingerlike, Pseudopod#Morphology, lobose pseudopods and tubular mitochondrial cristae. In trad ...

. It gets its name from '' Acanthamoeba'', its best-known member. However, it also includes other species, such as '' Comandonia operculata'' and '' Protacanthamoeba bohemica''. Many kinds of Acanthamoebidae are highly prevalent in the soil and water of a variety of environments. They are similar to Hartmannella, but have differently structured

pseudopodia A pseudopod or pseudopodium (: pseudopods or pseudopodia) is a temporary arm-like projection of a eukaryotic cell membrane that is emerged in the direction of movement. Filled with cytoplasm, pseudopodia primarily consist of actin filaments and ...

, in regard to the

actin Actin is a family of globular multi-functional proteins that form microfilaments in the cytoskeleton, and the thin filaments in muscle fibrils. It is found in essentially all eukaryotic cells, where it may be present at a concentration of ...

microfilaments Microfilaments, also called actin filaments, are protein filaments in the cytoplasm of eukaryotic cells that form part of the cytoskeleton. They are primarily composed of polymers of actin, but are modified by and interact with numerous other p ...

that comprise them. Its most prominent member, ''Acanthamoeba'', can be potentially pathogenic to humans and animals. It has been described as having a common origin with the Entamoebidae and Dictyosteliida.

Structure

Members of Acanthamoebidae have a specific form of pseudopodia, dubbed acanthopodia. These acanthopodia are continuously formed and reabsorbed, protrude from every area of the cell's surface, and are usually, short and fine. An exception would be ''A. astronyxis'' and ''A. comandoni'', in which the acanthopodia may be quite long. Sawyer and Griffin point out " ndles of actin microfilaments extend as rigid cores into acanthopodia". They are constantly formed and reabsorbed to induce locomotion, during which time the cell is typically triangular or cone-shaped. The advancing acanthopodia are "wide and tongue-shaped, with irregular margins and

filopodia Filopodia (: filopodium) are slender cytoplasmic projections that extend beyond the leading edge of lamellipodia in migrating cells. Within the lamellipodium, actin ribs are known as ''microspikes'', and when they extend beyond the lamellipod ...

." Sawyer and Griffin also note that the many acanthopodia contain axial bundles of the actin microfilaments, resulting in the irregular shape of the pseudopodia. In regards to the typical physical size of the family Acanthamoebidae, they rarely grow larger than 65 μm or are smaller than 30 μm.

Classification

The family Acanthamoebidae belongs to the order Centramoebida in the class Discosea, phylum

. Within the family Acanthamoebidae are the following genera: * '' Acanthamoeba'' – 33 species. * '' Comandonia'' – 1 species. * '' Dracoamoeba'' – 1 species. * '' Luapeleamoeba'' – 2 species. * '' Protacanthamoeba'' – 3 species. * '' Vacuolamoeba'' – 1 species.

Prevalence

Members of Acanthamoebidae are highly prevalent in a variety of environments. In

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, members (as well as Naegleria) were found in 68.7% of tapwater samples taken, despite purification. Acanthamoebidae were also found in the St. Martin River near

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, and are very common in the surface waters of many oceans.

Pathology

''Acanthamoeba'' spp. can be potentially pathogenic to humans and animals. Typically, a person or animal with a normally functioning immune system can avoid infection, but they "are known to be the opportunistic

pathogens In biology, a pathogen (, "suffering", "passion" and , "producer of"), in the oldest and broadest sense, is any organism or agent that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a germ. The term ...

in granulomatous amoebic encephalitis (GAE), a chronic disease of immunocompromised hosts such as

AIDS The HIV, human immunodeficiency virus (HIV) is a retrovirus that attacks the immune system. Without treatment, it can lead to a spectrum of conditions including acquired immunodeficiency syndrome (AIDS). It is a Preventive healthcare, pr ...

patients and transplants recipients." GAE is the result of microscopic cysts that form in the central nervous system. ''Acanthamoeba ''can also be the source of infections in the lungs, sinuses, skin, and eyes.

References

{{Authority control Amoebozoa families Discosea