Amoeboid

Amoeboids are single-celled life-forms characterized by an irregular shape.

"Amoeboid" and "amœba" are often used interchangeably even by biologists, and especially refer to a creature moving by using pseudopod

Pseudopod

Pseudopods or pseudopodia are temporary projections of eukaryotic cells. Cells that possess this faculty are generally referred to as amoeboids. Pseudopodia extend and contract by the reversible assembly of actin subunits into microfilaments...

ia. Most references to "amoebas" or "amoebae" are to amoeboids in general rather than to the specific genus Amoeba

Amoeba

Amoeba is a genus of Protozoa.History=The amoeba was first discovered by August Johann Rösel von Rosenhof in 1757. Early naturalists referred to Amoeba as the Proteus animalcule after the Greek god Proteus, who could change his shape...

. The genus Amoeba and amoeboids in general both derive their names from the ancient Greek word for change.

Structure

Amoeboids move using pseudopodia

Amoeboid movement

Amoeboid movement is a crawling-like type of movement accomplished by protrusion of cytoplasm of the cell involving the formation of pseudopodia. The cytoplasm slides and forms a pseudopodium in front to move the cell forward. This type of movement has been linked to changes in action potential;...

, which are bulges of cytoplasm

Cytoplasm

The cytoplasm is a small gel-like substance residing between the cell membrane holding all the cell's internal sub-structures , except for the nucleus. All the contents of the cells of prokaryote organisms are contained within the cytoplasm...

.

Amoebas breathe using their entire cell membrane

Cell membrane

The cell membrane or plasma membrane is a biological membrane that separates the interior of all cells from the outside environment. The cell membrane is selectively permeable to ions and organic molecules and controls the movement of substances in and out of cells. It basically protects the cell...

 that is constantly immersed in water. Excess water can cross into the cytosol

Cytosol

The cytosol or intracellular fluid is the liquid found inside cells, that is separated into compartments by membranes. For example, the mitochondrial matrix separates the mitochondrion into compartments....

. Amoebas have a contractile vacuole

Vacuole

A vacuole is a membrane-bound organelle which is present in all plant and fungal cells and some protist, animal and bacterial cells. Vacuoles are essentially enclosed compartments which are filled with water containing inorganic and organic molecules including enzymes in solution, though in certain...

 to expel excess water.

Food sources vary in amoeboids. They may consume bacteria

Bacteria

Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...

 or other protist

Protist

Protists are a diverse group of eukaryotic microorganisms. Historically, protists were treated as the kingdom Protista, which includes mostly unicellular organisms that do not fit into the other kingdoms, but this group is contested in modern taxonomy...

s. Some are detritivore

Detritivore

Detritivores, also known as detritophages or detritus feeders or detritus eaters or saprophages, are heterotrophs that obtain nutrients by consuming detritus . By doing so, they contribute to decomposition and the nutrient cycles...

s and eat dead organic material. They extend a pair of pseudopodia around food. They fuse to make a food vacuole which then fuses with a lysosome

Lysosome

thumb|350px|Schematic of typical animal cell, showing subcellular components. [[Organelle]]s: [[nucleoli]] [[cell nucleus|nucleus]] [[ribosomes]] [[vesicle |vesicle]] rough [[endoplasmic reticulum]]...

 to add digestive chemicals. Undigested food is expelled at the cell membrane.

Amoebas use pseudopodia to move and feed. They are powered by flexible microfilament

Microfilament

Microfilaments are the thinnest filaments of the cytoskeleton, a structure found in the cytoplasm of all eukaryotic cells. These linear polymers of actin subunits are flexible and relatively strong, resisting buckling by multi-piconewton compressive forces and filament fracture by nanonewton...

s near the membrane. Microfilaments are at least 50% of the cytoskeleton

Cytoskeleton

The cytoskeleton is a cellular "scaffolding" or "skeleton" contained within a cell's cytoplasm and is made out of protein. The cytoskeleton is present in all cells; it was once thought to be unique to eukaryotes, but recent research has identified the prokaryotic cytoskeleton...

. The other parts are more stiff and are composed of intermediate filament

Intermediate filament

Intermediate filaments are a family of related proteins that share common structural and sequence features. Intermediate filaments have an average diameter of 10 nanometers, which is between that of 7 nm actin , and that of 25 nm microtubules, although they were initially designated...

s and microtubule

Microtubule

Microtubules are a component of the cytoskeleton. These rope-like polymers of tubulin can grow as long as 25 micrometers and are highly dynamic. The outer diameter of microtubule is about 25 nm. Microtubules are important for maintaining cell structure, providing platforms for intracellular...

s. These are not used in amoeboid movement, but are stiff skeletons on which organelles are supported or can move on.

The shells of amoebas are often composed of calcium

Calcium

Calcium is the chemical element with the symbol Ca and atomic number 20. It has an atomic mass of 40.078 amu. Calcium is a soft gray alkaline earth metal, and is the fifth-most-abundant element by mass in the Earth's crust...

. The proteins or materials are synthesised in the cell and exported just outside the cell membrane.

Amoebas seem to have connections with two phyla composed of multicellular organism

Multicellular organism

Multicellular organisms are organisms that consist of more than one cell, in contrast to single-celled organisms. Most life that can be seen with the the naked eye is multicellular, as are all animals and land plants.-Evolutionary history:Multicellularity has evolved independently dozens of times...

s of the lineage of fungus-like protists. The two phyla are Myxomycota (plasmodial slime molds), and Acrasiomycota

Acrasiomycota

Acrasidae is a family of slime molds which belongs to the protist group Percolozoa. The name acrasio- comes from the Greek Akrasia, meaning "acting against one's judgement." This group consists of cellular slime molds....

 (cellular slime molds). These two phyla use amoeboid movement in their feeding stage. The former is basically a giant multinucleate amoeba, while the latter lives solitary until food runs out; in which a colony of these functions as a unit. Myxomycetes use amoeboid gametes, as well.

Diversity

They have appeared in a number of different groups. Some cells in multicellular animals may be amoeboid, for instance human white blood cell

White blood cell

White blood cells, or leukocytes , are cells of the immune system involved in defending the body against both infectious disease and foreign materials. Five different and diverse types of leukocytes exist, but they are all produced and derived from a multipotent cell in the bone marrow known as a...

s, which consume pathogens. Many protist

Protist

Protists are a diverse group of eukaryotic microorganisms. Historically, protists were treated as the kingdom Protista, which includes mostly unicellular organisms that do not fit into the other kingdoms, but this group is contested in modern taxonomy...

s also exist as individual amoeboid cells, or take such a form at some point in their life-cycle. The most famous such organism is Amoeba proteus

Amoeba

Amoeba is a genus of Protozoa.History=The amoeba was first discovered by August Johann Rösel von Rosenhof in 1757. Early naturalists referred to Amoeba as the Proteus animalcule after the Greek god Proteus, who could change his shape...

; the name amoeba is variously used to describe its close relatives, other organisms similar to it, or the amoeboids in general.

Classification

As amoebas themselves are polyphyletic and subject to some imprecision in definition, the term "amoeboid" does not provide identification of an organism, and is better understood as description of locomotion.

When used in the broader sense, the term can include many different groups. One source includes 97 different genera. Others include far fewer.

Older classification

In older classification systems, amoeboids, under the taxon name Sarcodina, had been divided into several morphological categories based on the form and structure of their pseudopod

Pseudopod

Pseudopods or pseudopodia are temporary projections of eukaryotic cells. Cells that possess this faculty are generally referred to as amoeboids. Pseudopodia extend and contract by the reversible assembly of actin subunits into microfilaments...

s.

Amoeboids with pseudopods supported by regular arrays of microtubule

Microtubule

Microtubules are a component of the cytoskeleton. These rope-like polymers of tubulin can grow as long as 25 micrometers and are highly dynamic. The outer diameter of microtubule is about 25 nm. Microtubules are important for maintaining cell structure, providing platforms for intracellular...

s were called actinopods, whereas those that weren't were called rhizopods, which were further subdivided into lobose, filose, and reticulose amoebae. In contrast to "rhizopods", where most of their morphologies can be mapped to modern classification systems, "actinopods" appear to be extensively polyphyletic. Actinopods are divided into radiolaria and heliozoa

Heliozoa

Heliozoa are phagotrophs. They are roughly spherical amoeboids with many stiff, microtubule-supported projections called axopods radiating outward from the cell surface. These give them the characteristic sun-like appearance for which they are named, and are variously used for capturing food,...

 (itself a polyphyletic grouping).

Finally, there was also a strange group of giant marine amoeboids, the xenophyophore

Xenophyophore

Xenophyophores are marine protozoa, giant single-celled organisms found throughout the world's oceans, at depths of up to 10,641 meters . Xenophyophores are found in the greatest numbers on the abyssal plains of the deep ocean. They were first described as sponges in 1889, then as testate...

s, that did not fall into any of these categories.

Modern classification

More modern classifications are based upon cladistics

Cladistics

Cladistics is a method of classifying species of organisms into groups called clades, which consist of an ancestor organism and all its descendants . For example, birds, dinosaurs, crocodiles, and all descendants of their most recent common ancestor form a clade...

. It has been stated that most amoeboid are now grouped in Amoebozoa

Amoebozoa

The Amoebozoa are a major group of amoeboid protozoa, including the majority that move by means ofinternal cytoplasmic flow. Their pseudopodia are characteristically blunt and finger-like,...

 or Rhizaria

Rhizaria

The Rhizaria are a species-rich supergroup of unicellular eukaryotes. This supergroup was proposed by Cavalier-Smith in 2002. They vary considerably in form, but for the most part they are amoeboids with filose, reticulose, or microtubule-supported pseudopods...

. However, in contexts where "amoeboid" is defined more loosely, there are many amoeboid species that are in the Excavata clade.

Phylogenetic analyses place these genera into the following groups (not all of these are considered amoeboid (or "amoebas") by all sources):

Grouping	Genera	Morphology
Amoebozoa Amoebozoa The Amoebozoa are a major group of amoeboid protozoa, including the majority that move by means ofinternal cytoplasmic flow. Their pseudopodia are characteristically blunt and finger-like,...	Lobosea Lobosea Lobosea is a group of Amoebozoa. An example is Arcellinida.Sensu strico, it can refer to Tubulinea. However, sensu lato, it can also refer more generally to a paraphyletic group of lobose Amoebozoa. Formal classification of lobose amoebae remains speculative, and the older, less specific terms... : Acanthamoeba Acanthamoeba Acanthamoeba is a genus of amoebae, one of the most common protozoa in soil, and also frequently found in fresh water and other habitats. The cells are small, usually 15 to 35 μm in length and oval to triangular in shape when moving. The pseudopods form a clear hemispherical lobe at the anterior,... , Amoeba, Balamuthia, Chaos Chaos (amoeba) Chaos is a genus of giant amoebae. The largest and best known species, Chaos carolinensis, can reach lengths of 5mm, although most specimens fall between 1 and 3 mm.... , Clydonella Clydonella Clydonella is a genus of Amoebozoa.... , Discamoeba Discamoeba Discamoeba is a genus of Amoebozoa.... , Echinamoeba, Filamoeba, Flabellula Flabellula Flabellula is a genus of Amoebozoa.It is sometimes spelled "Flabelulla".... , Gephyramoeba Gephyramoeba Gephyramoeba is a genus of heterotrophic amoebae, morphologically similar to genera Rhizamoeba and Leptomyxa, although it is not genetically related to either of these genera.... , Glaeseria Glaeseria Glaeseria is a genus of Amoebozoa, including the species Glaeseria mira and Glaeseria testudinis.... , Hartmannella Hartmannella Hartmannella is a genus of Amoebozoa, including the following species:*Hartmannella abertawensis*Hartmannella agricola*Hartmannella cantabrigiensis*Hartmannella crumpae*Hartmannella hibernica*Hartmannella hyalina... , Hydramoeba, Korotnevella Korotnevella Korotnevella is a genus of Amoebozoa.It includes the species Korotnevella hemistylolepis.... , Leptomyxa, Lingulamoeba Lingulamoeba Lingulamoeba is a genus of Amoebozoa.... , Mastigina, Mayorella Mayorella Mayorella is a genus of Amoebozoa.It includes:* Mayorella bigemma* Mayorella palestinensis* Mayorella yomomma... , Metachaos, Neoparamoeba Neoparamoeba Neoparamoeba is a genus of Amoebozoa.... , Paramoeba Paramoeba Paramoeba is a genus of parasites.It can cause infection in fish.... , Polychaos Polychaos Polychaos is an amoeboid genus in the Amoebozoa group. Several characters unite the species in this genus. The pseudopods meld at their bases when the organism is moving, and have dorsal, longitudinal ridges... , Phreatamoeba, Platyamoeba Platyamoeba Platyamoeba is a genus of Amoebozoa.... , Protoacanthamoeba Protoacanthamoeba Protoacanthamoeba is an amoeboid genus.... , Rhizamoeba Rhizamoeba Rhizamoeba is an Amoebozoa genus.... , Saccamoeba, Sappinia Sappinia Sappinia is a genus of Amoebozoa.It includes the species Sappinia diploidea and Sappinia pedata.... , Stereomyxa, Thecamoeba Thecamoeba Thecamoeba is a genus of Amoebozoa.It includes the species Thecamoeba hilla .... , Trichamoeba Trichamoeba Trichamoeba is a genus of Amoebozoa.It includes the species Trichamoeba villosa.... , Trichosphaerium, Unda Unda Unda is a genus of Amoebozoa.... , Vannella Vannella Vannella is a genus of Amoebozoa.It includes the following species:* Vannella aberdonica* Vannella anglica* Vannella arabica* Vannella devonica* Vannella ebro* Vannella epipetala* Vannella lata* Vannella miroides... , Vexillifera Vexillifera Vexillifera is a genus of Amoebozoa.It is possible for it to be present in swimming pools.... Conosa Conosa Conosa is a grouping of Amoebozoa. It is subdivided into two infraphyla – Mycetozoa and Archamoebae.Conosa includes the species Dictyostelium discoideum and Entamoeba histolytica, among others.... : Endamoeba Endamoeba Endamoeba is a genus of amoeboids in Amoebozoa. It includes the species Endamoeba blattae, Endamoeba lutea, and Endamoeba similans.... , Entamoeba Entamoeba Entamoeba is a genus of Amoebozoa found as internal parasites or commensals of animals.In 1875, Fedor Lösch described the first proven case of amoebic dysentery in St Petersburg, Russia. He referred to the amoeba he observed microscopically as 'Amoeba coli'; however it is not clear whether he was... , Hyperamoeba Hyperamoeba Hyperamoeba is a former genus of amoeboid protists, described in 1923. It has been shown to be polyphyletic, and the species formerly contained in it have been divided among the genera Physarum, Stemonitis and Didymium.... , Mastigamoeba Mastigamoeba Mastigamoeba is an amoeboid genus. The exact classification is subject to debate, including the assumption that it is synonymous with Phreatamoeba.It includes Mastigamoeba balamuthi.... , Mastigella Mastigella Mastigella is an amoeboid genus belonging to Amoebozoa.... , Pelomyxa Pelomyxa Pelomyxa are giant amoebae, usually 500-800 μm but occasionally up to 5 mm in length. One notable species is P. palustris; other described species may be synonyms, or have been moved to the unrelated genus Chaos...	Lobose pseudopods (Lobosea Lobosea Lobosea is a group of Amoebozoa. An example is Arcellinida.Sensu strico, it can refer to Tubulinea. However, sensu lato, it can also refer more generally to a paraphyletic group of lobose Amoebozoa. Formal classification of lobose amoebae remains speculative, and the older, less specific terms... ): Lobose pseudopods are blunt, and there may be one or several on a cell, which is usually divided into a layer of clear ectoplasm surrounding more granular endoplasm.
Rhizaria Rhizaria The Rhizaria are a species-rich supergroup of unicellular eukaryotes. This supergroup was proposed by Cavalier-Smith in 2002. They vary considerably in form, but for the most part they are amoeboids with filose, reticulose, or microtubule-supported pseudopods...	Cercozoa Cercozoa The Cercozoa are a group of protists. They are sometimes described as a kingdom.-Characteristics:The group includes most amoeboids and flagellates that feed by means of filose pseudopods. These may be restricted to part of the cell surface, but there is never a true cytostome or mouth as found in... : Filosa: Gyromitus Gyromitus Gyromitus is a rhizaria genus.It is a thaumatomonad.... , Paulinella Paulinella Paulinella is a genus of about nine species of freshwater amoeboids.Its most famous member is the photosynthetic P. chromatophora which has recently taken on a cyanobacterium as an endosymbiont... Endomyxa Endomyxa Endomyxa is a subphylum of Rhizaria.... : Vampyrella	Filose pseudopods (Filosa): Filose pseudopods are narrow and tapering. The vast majority of filose amoebae, including all those that produce shells, are placed within the Cercozoa Cercozoa The Cercozoa are a group of protists. They are sometimes described as a kingdom.-Characteristics:The group includes most amoeboids and flagellates that feed by means of filose pseudopods. These may be restricted to part of the cell surface, but there is never a true cytostome or mouth as found in...  together with various flagellates that tend to have amoeboid forms. The naked filose amoebae also includes vampyrellid Vampyrellid The Vampyrellidae are a group of cercozoans with filose pseudopods and lacking shells. Vampyrella is typical of the group, which also contains genera such as Platyreta and Arachnula.The term "Aconchulinida" is sometimes used for vampyrellid... s. Reticulose pseudopods (Endomyxa Endomyxa Endomyxa is a subphylum of Rhizaria.... ): Reticulose pseudopods are cytoplasmic strands that branch and merge to form a net. They are found most notably among the Foraminifera Foraminifera The Foraminifera , or forams for short, are a large group of amoeboid protists which are among the commonest plankton species. They have reticulating pseudopods, fine strands of cytoplasm that branch and merge to form a dynamic net... , a large group of marine protists that generally produce multi-chambered shells. There are only a few sorts of naked reticulose amoeboids, notably the gymnophryid Gymnophryid Gymnophryidae is a small family of amoeboids that lack shells and produce thin, reticulose pseudopods. These contain microtubules and have a granular appearance, owing to the presence of extrusomes, but are distinct from the pseudopods of Foraminifera... s, and their relationships are not certain. Radiolarians are a subgroup of actinopods that are now grouped with rhizarians.
Excavata Excavate The excavates are a major kingdom of unicellular eukaryotes, often known as Excavata. The phylogenetic category Excavata, proposed by Cavalier-Smith in 2002, contains a variety of free-living and symbiotic forms, and also includes some important parasites of humans.-Characteristics:Many excavates...	Heterolobosea: Vahlkampfiidae Vahlkampfiidae Vahlkampfiidae is a family of Heterolobosea.It includes the following genera:* Monopylocystis* Naegleria* Neovahlkampfia* Paravahlkampfia* Psalteriomonas* Sawyeria* Tetramitus* Vahlkampfia* Willaertia... : Monopylocystis Monopylocystis Monopylocystis visvesvarai is a species of amoebae, placed in the monotypic genus Monopylocystis, and belonging to the group Heterolobosea.... , Naegleria Naegleria Naegleria is a eukaryotic genus. The genus was named after French zoologist Mathieu Naegler.Species include:* Naegleria fowleri, which causes a rare and generally fatal disease in humans* Naegleria gruberi-External links:... , Neovahlkampfia Neovahlkampfia Neovahlkampfia is an genus of Amoebozoa.... , Paratetramitus, Paravahlkampfia Paravahlkampfia Paravahlkampfia is an genus of Amoebozoa.... , Psalteriomonas Psalteriomonas Psalteriomonas is a genus of amoebae in the group of Heterolobosea.... , Sawyeria Sawyeria Sawyeria marylandensis is a species of amoebae, placed in the monotypic genus Sawyeria, and belonging to the group Heterolobosea.... , Tetramitus Tetramitus Tetramitus is an genus of Amoebozoa.... , Vahlkampfia Vahlkampfia Vahlkampfia is an genus of amoeboids in Heterolobosea.... , Willaertia Willaertia Willaertia is an amoeboid genus of Heterolobosea.... Gruberellidae Gruberellidae Gruberellidae is a family of Heterolobosea.... : Stachyamoeba Parabasalidea: Dientamoeba, Histomonas Other: Rosculus, Acrasis, Heteramoeba, Learamoeba, Stygamoeba	The Heterolobosea, includes protists that can transform between amoeboid and flagellate Flagellate Flagellates are organisms with one or more whip-like organelles called flagella. Some cells in animals may be flagellate, for instance the spermatozoa of most phyla. Flowering plants do not produce flagellate cells, but ferns, mosses, green algae, some gymnosperms and other closely related plants...  forms.
Chromalveolate Chromalveolate Chromalveolata is a eukaryote supergroup first proposed by Thomas Cavalier-Smith as a refinement of his kingdom Chromista, which was first put forward in 1981. Chromalveolata was proposed to represent the result of a single secondary endosymbiosis between a line descending from a bikont and a red...	Heterokont Heterokont The heterokonts or stramenopiles are a major line of eukaryotes currently containing more than 100,000 known species. Most are algae, ranging from the giant multicellular kelp to the unicellular diatoms, which are a primary component of plankton... : Hyalodiscus Hyalodiscus Hyalodiscus is an extant genus of diatom known also from the fossil record.... , Labyrinthula Labyrinthula Labyrinthula is a genus of heterokont, comprising ten species.... Alveolata Alveolate The alveolates are a major line of protists.-Phyla:There are four phyla, which are very divergent in form, but are now known to be close relatives based on various ultrastructural and genetic similarities:... : Pfiesteria Pfiesteria Pfiesteria is a genus of heterotrophic dinoflagellates that has been associated with harmful algal blooms and fish kills. Pfiesteria complex organisms were claimed to be responsible for large fish kills in the 1980s and 1990s on the coast of North Carolina and in tributaries of the Chesapeake Bay...	Hyalodiscus Hyalodiscus Hyalodiscus is an extant genus of diatom known also from the fossil record.... and Pfiesteria Pfiesteria Pfiesteria is a genus of heterotrophic dinoflagellates that has been associated with harmful algal blooms and fish kills. Pfiesteria complex organisms were claimed to be responsible for large fish kills in the 1980s and 1990s on the coast of North Carolina and in tributaries of the Chesapeake Bay... are sometimes considered to have amoeboid characteristics.
Nucleariid Nucleariid The nucleariids are a group of amoebae with filose pseudopods, known mostly from soils and freshwater. They are distinguished from the similar vampyrellids mainly by having mitochondria with discoid cristae.-Classification:...	Micronuclearia Micronuclearia Micronuclearia is a Nucleariid genus.It includes the species Micronuclearia podoventralis.... , Nuclearia Nuclearia Nuclearia is a nucleariid genus.Species include:* Nuclearia delicatula* Nuclearia moebiusi* Nuclearia pattersoni Dyková, Veverková, Fiala, Macháčková & Pecková, 2003* Nuclearia simplex* Nuclearia thermophila...	Nucleariid Nucleariid The nucleariids are a group of amoebae with filose pseudopods, known mostly from soils and freshwater. They are distinguished from the similar vampyrellids mainly by having mitochondria with discoid cristae.-Classification:... s appear to be close relatives of animal Animal Animals are a major group of multicellular, eukaryotic organisms of the kingdom Animalia or Metazoa. Their body plan eventually becomes fixed as they develop, although some undergo a process of metamorphosis later on in their life. Most animals are motile, meaning they can move spontaneously and... s and fungi Fungus A fungus is a member of a large group of eukaryotic organisms that includes microorganisms such as yeasts and molds , as well as the more familiar mushrooms. These organisms are classified as a kingdom, Fungi, which is separate from plants, animals, and bacteria... .
Ungrouped/ unknown	Adelphamoeba, Astramoeba, Cashia, Dactylamoeba, Dinamoeba, Flagellipodium, Flamella, Gibbodiscus, Gocevia, Gruberella, Hollandella, Iodamoeba, Malamoeba, Nollandia, Oscillosignum, Paragocevia, Parvamoeba, Pernina, Pontifex, Protonaegleria, Pseudomastigamoeba, Plaesiobystra, Rugipes, Striamoeba, Striolatus, Subulamoeba, Theratromyxa, Trienamoeba, Trimastigamoeba, Vampyrellium

Pathogenic interactions with other organisms

Some amoeboids can infect other organisms pathogen

Pathogen

A pathogen gignomai "I give birth to") or infectious agent — colloquially, a germ — is a microbe or microorganism such as a virus, bacterium, prion, or fungus that causes disease in its animal or plant host...

ically (causing disease):

• Entamoeba histolytica
  Entamoeba histolytica
  Entamoeba histolytica is an anaerobic parasitic protozoan, part of the genus Entamoeba. Predominantly infecting humans and other primates, E. histolytica is estimated to infect about 50 million people worldwide...
  
  is the cause of amoebiasis
  Amoebiasis
  Entamebiasis is a term for the infection more commonly known as amoebiasis.It became the preferred term in MeSH in 1991, but the term amoebiasis is used by the World Health Organization and by those working in the field of amoebiasis research....
  
  , or amoebic dysentery.
• Naegleria fowleri
  Naegleria fowleri
  Naegleria fowleri is a free-living excavate form of protist typically found in warm bodies of fresh water, such as ponds, lakes, rivers, and hot springs. It is also found in soil, near warm-water discharges of industrial plants, and unchlorinated swimming pools in an amoeboid or temporary...
  
  (the "brain-eating amoeba") is a fresh-water-native species that can be fatal to humans if introduced through the nose.
• Acanthamoeba
  Acanthamoeba
  Acanthamoeba is a genus of amoebae, one of the most common protozoa in soil, and also frequently found in fresh water and other habitats. The cells are small, usually 15 to 35 μm in length and oval to triangular in shape when moving. The pseudopods form a clear hemispherical lobe at the anterior,...
  
  can cause amoebic keratitis
  Keratitis
  Keratitis is a condition in which the eye's cornea, the front part of the eye, becomes inflamed. The condition is often marked by moderate to intense pain and usually involves impaired eyesight.-Types:...
  
   and encephalitis
  Encephalitis
  Encephalitis is an acute inflammation of the brain. Encephalitis with meningitis is known as meningoencephalitis. Symptoms include headache, fever, confusion, drowsiness, and fatigue...
  
   in humans.
• Balamuthia mandrillaris
  Balamuthia mandrillaris
  Balamuthia mandrillaris is a free-living leptomyxid amoeba which is known to cause amoebiasis in humans, especially the deadly neurological condition known as granulomatous amoebic encephalitis . Balamuthia has not been definitively isolated in nature, but it is believed to be distributed...
  
  is the cause of (often fatal) granulomatous amoebic meningoencephalitis

External links

• The Amoebae website brings together information from published sources.
• Amoebas are more than just blobs
• Sun Animacules and Amoebas
• Molecular Expressions Digital Video Gallery: Pond Life - Amoeba (Protozoa) Some good, informative Amoeba videos.
• Amoebae: Protists Which Move and Feed Using Pseudopodia at the Tree of Life web project