Acanthamoeba
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''Acanthamoeba'' is a genus of
amoebae An amoeba (; less commonly spelled ameba or amœba; : amoebas (less commonly, amebas) or amoebae (amebae) ), often called an amoeboid, is a type of cell or unicellular organism with the ability to alter its shape, primarily by extending and r ...
that are commonly recovered from soil,
fresh water Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salt (chemistry), salts and other total dissolved solids. The term excludes seawater and brackish water, but it does include ...
, and other
habitats In ecology, habitat refers to the array of resources, biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species' habitat can be seen as the physical manifestation of its ...
. The genus ''Acanthamoeba'' has two stages in its life cycle, the metabolically active
trophozoite 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. The complementary form of the t ...
stage and a dormant, stress-resistant
cyst A cyst is a closed sac, having a distinct envelope and division compared with the nearby tissue. Hence, it is a cluster of cells that have grouped together to form a sac (like the manner in which water molecules group together to form a bubb ...
stage. In nature, ''Acanthamoeba'' species are generally free-living
bacterivore A bacterivore is an organism which obtains energy and nutrients primarily or entirely from the consumption of bacteria. The term is most commonly used to describe free-living, heterotrophic, microscopic organisms such as nematodes as well as many s ...
s. However, they are also opportunistic pathogens able to cause serious and potentially fatal infections in humans and other animals.


Distribution

''Acanthamoeba'' spp. are among the most prevalent protozoa found in the environment. They are distributed worldwide, and have been isolated from soil, air, sewage, seawater, chlorinated swimming pools, domestic tap water, bottled water, dental treatment units, hospitals, air-conditioning units, and contact lens cases. Additionally, they have been isolated from human skin, nasal cavities, throats, and intestines, as well as plants and other mammals.


Role in disease

Diseases caused by ''Acanthamoeba'' include
keratitis Keratitis is a condition in which the human eye, eye's cornea, the clear dome on the front surface of the eye, becomes inflammation, inflamed. The condition is often marked by moderate to intense pain and usually involves any of the following sy ...
and
granulomatous amoebic encephalitis Granulomatous amoebic encephalitis (GAE) is a rare, often fatal, subacute-to-chronic central nervous system disease caused by certain species of free-living amoebae of the genera ''Acanthamoeba'', ''Balamuthia mandrillaris, Balamuthia'' and ''Sa ...
(GAE). The latter is often but not always seen in immunosuppressed patients. GAE is caused by the amoebae entering the body through an open wound and then spreading to the brain. The combination of host immune responses and secreted amoebal
protease A protease (also called a peptidase, proteinase, or proteolytic enzyme) is an enzyme that catalysis, catalyzes proteolysis, breaking down proteins into smaller polypeptides or single amino acids, and spurring the formation of new protein products ...
s causes massive brain swelling resulting in death in about 95% of those infected.


Granulomatous amoebic encephalitis (GAE)

Granulomatous amoebic encephalitis (GAE) is caused by amoebic infection of the central nervous system (CNS). It is characterized by neurological symptoms including headache, seizures, and mental-status abnormalities. These worsen progressively over weeks to months, leading to death in most patients. Infection is generally associated with underlying conditions such as
immunodeficiency Immunodeficiency, also known as immunocompromise, is a state in which the immune system's ability to fight infectious diseases and cancer is compromised or entirely absent. Most cases are acquired ("secondary") due to extrinsic factors that aff ...
, diabetes, malignancies, malnutrition,
systemic lupus erythematosus Lupus, formally called systemic lupus erythematosus (SLE), is an autoimmune disease in which the body's immune system mistakenly attacks healthy tissue in many parts of the body. Symptoms vary among people and may be mild to severe. Common ...
, and alcoholism. The parasite enters the body through cuts in the skin or by being inhaled into the upper respiratory tract. The parasite then spreads through the blood into the CNS. ''Acanthamoeba'' crosses the
blood–brain barrier The blood–brain barrier (BBB) is a highly selective semipermeable membrane, semipermeable border of endothelium, endothelial cells that regulates the transfer of solutes and chemicals between the circulatory system and the central nervous system ...
by means that are not yet understood. Subsequent invasion of the connective tissue and induction of pro-inflammatory responses leads to neuronal damage that can be fatal within days. Pure granulomatous lesions are rare in patients with AIDS and other related immunodeficiency states, as the patients do not have adequate numbers of CD+ve T-cells to mount a granulomatous response to ''Acanthamoeba'' infection in CNS and other organs and tissues. A perivascular cuffing with amoebae in necrotic tissue is usual finding in the AIDS and related T-cell immunodeficiency conditions.
Brain biopsy Brain biopsy is the removal of a small piece of brain tissue for the diagnosis of abnormalities of the brain. It is used to diagnose tumors, infection, inflammation, and other brain disorders. By examining the tissue sample under a microscope, th ...
normally reveals severe
oedema Edema (American English), also spelled oedema (British English), and also known as fluid retention, swelling, dropsy and hydropsy, is the build-up of fluid in the body's tissue. Most commonly, the legs or arms are affected. Symptoms may inclu ...
and hemorrhagic
necrosis Necrosis () is a form of cell injury which results in the premature death of cells in living tissue by autolysis. The term "necrosis" came about in the mid-19th century and is commonly attributed to German pathologist Rudolf Virchow, who i ...
. A patient who has contracted this illness usually displays subacute symptoms, including altered mental status, headaches, fever, neck stiffness, seizures, and focal neurological signs (such as cranial nerve palsies and coma), all leading to death within one week to several months. Due to the rarity of this parasite and a lack of knowledge, no good diagnoses or treatments for ''Acanthamoeba'' infection are now known. ''Acanthamoeba'' keratitis cases in the past have resolved from a therapy consisting of atropine and some other drugs with no antimicrobial effects. Recent publications show
atropine Atropine is a tropane alkaloid and anticholinergic medication used to treat certain types of nerve agent and pesticide poisonings as well as some types of slow heart rate, and to decrease saliva production during surgery. It is typically give ...
to interfere with the protist's
CHRM1 The muscarinic acetylcholine receptor M1, also known as the cholinergic receptor, muscarinic 1, is a muscarinic receptor that in humans is encoded by the ''CHRM1'' gene. It is localized to 11q13. This receptor is found mediating slow EPSP at ...
receptor, causing cell death. Infection usually mimics that of bacterial leptomeningitis, tuberculous
meningitis Meningitis is acute or chronic inflammation of the protective membranes covering the brain and spinal cord, collectively called the meninges. The most common symptoms are fever, intense headache, vomiting and neck stiffness and occasion ...
, or viral encephalitis. The misdiagnosis often leads to erroneous, ineffective treatment. In the case that the ''Acanthamoeba'' is diagnosed correctly, the current treatments, such as
amphotericin B Amphotericin B is an antifungal medication used for serious fungal infections and leishmaniasis. The fungal infections it is used to treat include mucormycosis, aspergillosis, blastomycosis, candidiasis, coccidioidomycosis, and cryptococ ...
,
rifampicin Rifampicin, also known as rifampin, is an ansamycin antibiotic used to treat several types of bacterial infections, including tuberculosis (TB), ''Mycobacterium avium'' complex, leprosy, and Legionnaires' disease. It is almost always used tog ...
,
trimethoprim Trimethoprim (TMP) is an antibiotic used mainly in the treatment of bladder infections. Other uses include for middle ear infections and travelers' diarrhea. With sulfamethoxazole or dapsone it may be used for ''Pneumocystis'' pneumonia ...
-
sulfamethoxazole Sulfamethoxazole (SMZ or SMX) is an antibiotic. It is used for bacterial infections such as urinary tract infections, bronchitis, and prostatitis and is effective against both gram negative and positive bacteria such as ''Escherichia coli' ...
,
ketoconazole Ketoconazole, sold under the brand name Nizoral, among others, is an antiandrogen, antifungal drug, antifungal, and antiglucocorticoid medication used to treat a number of fungal infections. Applied to the skin it is used for fungal skin inf ...
,
fluconazole Fluconazole is an antifungal medication used for a number of fungal infections. These include candidiasis, blastomycosis, coccidioidomycosis, cryptococcosis, histoplasmosis, dermatophytosis, and tinea versicolor. It is also used to pr ...
,
sulfadiazine Sulfadiazine is an antibiotic. Used together with pyrimethamine, a dihydrofolate reductase inhibitor, it is the treatment of choice for toxoplasmosis, which is caused by a protozoan parasite. It is a second-line treatment for otitis media, pr ...
, or
albendazole Albendazole is a broad-spectrum antihelmintic and antiprotozoal agent of the benzimidazole type. It is used for the treatment of a variety of intestinal parasite infections, including ascariasis, pinworm infection, hookworm infection, trichuri ...
, are only tentatively successful. Correct and timely diagnosis, as well as improved treatment methods and an understanding of the parasite, are important factors in improving the outcome of infection by ''Acanthamoeba''. A paper published in 2013 has shown substantial effects of some FDA-approved drugs with an ''in vitro'' kill rate above 90%. These results were ''in vitro'' effects, but as the drugs are already approved, human infections can be targeted after dose calculations in clinical trials done with these diverse groups of drugs.


Acanthamoebic keratitis

When present in the eye, ''Acanthamoeba'' strains can cause acanthamoebic keratitis, which may lead to corneal ulcers or even blindness. This condition occurs most often among
contact lens Contact lenses, or simply contacts, are thin lenses placed directly on the surface of the eyes. Contact lenses are ocular prosthetic devices used by over 150 million people worldwide, and they can be worn to correct vision or for cosmetic ...
wearers who do not properly disinfect their lenses, exacerbated by a failure to wash hands prior to handling the lenses. Multipurpose contact lens solutions are largely ineffective against ''Acanthamoeba'', whereas hydrogen peroxide-based solutions have good disinfection characteristics. The first cure of a corneal infection was achieved in 1985 at
Moorfields Eye Hospital Moorfields Eye Hospital is a specialist National Health Service (NHS) eye hospital in Finsbury in the London Borough of Islington in London, England run by Moorfields Eye Hospital NHS Foundation Trust. Together with the UCL Institute of Ophthal ...
. In May 2007, Advanced Medical Optics, manufacturer of Complete Moisture Plus Contact Lens Solution products, issued a voluntary recall of their Complete Moisture Plus solutions. The fear was that contact lens wearers who used their solution were at higher risk of acanthamoebic keratitis than contact lens wearers who used other solutions. The manufacturer recalled the product after the
Centers for Disease Control The Centers for Disease Control and Prevention (CDC) is the national public health agency of the United States. It is a United States federal agency under the Department of Health and Human Services (HHS), and is headquartered in Atlanta, ...
in the United States found that 21 people had possibly received an ''Acanthamoeba'' infection after using Complete Moisture Plus in the month prior to diagnosis.


As a bacterial reservoir

Several species of bacteria that can cause human disease are also able to infect and replicate within ''Acanthamoeba'' species. These include ''
Legionella pneumophila ''Legionella pneumophila'', the primary causative agent for Legionnaires' disease, Legionnaire's disease, is an Aerobic organism, aerobic, pleomorphic, Flagellum, flagellated, non-spore-forming, Gram-negative bacteria, Gram-negative bacterium. ' ...
'', ''
Pseudomonas aeruginosa ''Pseudomonas aeruginosa'' is a common Bacterial capsule, encapsulated, Gram-negative bacteria, Gram-negative, Aerobic organism, aerobic–facultative anaerobe, facultatively anaerobic, Bacillus (shape), rod-shaped bacteria, bacterium that can c ...
'', and some strains of ''
Escherichia coli ''Escherichia coli'' ( )Wells, J. C. (2000) Longman Pronunciation Dictionary. Harlow ngland Pearson Education Ltd. is a gram-negative, facultative anaerobic, rod-shaped, coliform bacterium of the genus '' Escherichia'' that is commonly fo ...
'' and ''
Staphylococcus aureus ''Staphylococcus aureus'' is a Gram-positive spherically shaped bacterium, a member of the Bacillota, and is a usual member of the microbiota of the body, frequently found in the upper respiratory tract and on the skin. It is often posi ...
''. For some of these bacteria, replication inside ''Acanthamoeba'' has been associated with enhanced growth in
macrophage Macrophages (; abbreviated MPhi, φ, MΦ or MP) are a type of white blood cell of the innate immune system that engulf and digest pathogens, such as cancer cells, microbes, cellular debris and foreign substances, which do not have proteins that ...
s, and increased resistance to some antibiotics. Furthermore, due to the high prevalence of ''Acanthamoeba'' in the environment, these amoebae have been proposed to serve as an environmental reservoir for some human pathogens.


Ecology

''A. castellanii'' can be found at high densities in various soil ecosystems. It preys on bacteria, but also fungi and other protozoa. This species is able to lyse bacteria and produce a wide range of enzymes, such as cellulases or chitinases, and probably contributes to the breakdown of organic matter in soil, contributing to the
microbial loop The microbial loop describes a trophic pathway where, in aquatic systems, dissolved organic carbon (DOC) is returned to higher trophic levels via its incorporation into bacterial biomass, and then coupled with the classic food chain formed by ph ...
.


Physiology


Role as a model organism

Because ''Acanthamoeba'' does not differ greatly at the ultrastructural level from a mammalian cell, it is an attractive model for cell-biology studies; it is important in cellular microbiology, environmental biology, physiology, cellular interactions, molecular biology, biochemistry, and evolutionary studies, due to the organisms' versatile roles in the ecosystem and ability to capture prey by
phagocytosis Phagocytosis () is the process by which a cell (biology), cell uses its plasma membrane to engulf a large particle (≥ 0.5 μm), giving rise to an internal compartment called the phagosome. It is one type of endocytosis. A cell that performs ph ...
, act as vectors and reservoirs for microbial pathogens, and to produce serious human infections. In addition, ''Acanthamoeba'' has been used extensively to understand the molecular biology of
cell motility Motility is the ability of an organism to move independently using metabolism, metabolic energy. This biological concept encompasses movement at various levels, from whole organisms to cells and subcellular components. Motility is observed in ...
and cancer cell dormancy by in-depth exploration of the process of encystation. The recently available ''Acanthamoeba''
genome A genome is all the genetic information of an organism. It consists of nucleotide sequences of DNA (or RNA in RNA viruses). The nuclear genome includes protein-coding genes and non-coding genes, other functional regions of the genome such as ...
sequence revealed several
orthologs Sequence homology is the biological homology between DNA, RNA, or protein sequences, defined in terms of shared ancestry in the evolutionary history of life. Two segments of DNA can have shared ancestry because of three phenomena: either a spec ...
of genes employed in
meiosis Meiosis () is a special type of cell division of germ cells in sexually-reproducing organisms that produces the gametes, the sperm or egg cells. It involves two rounds of division that ultimately result in four cells, each with only one c ...
of sexual
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. These genes included ''
Spo11 Spo11 is a protein that in humans is encoded by the ''SPO11'' gene. Spo11, in a complex with mTopVIB, creates double strand breaks to initiate meiotic recombination. Its active site contains a tyrosine which ligates and dissociates with DNA to p ...
, Mre11,
Rad50 DNA repair protein RAD50, also known as RAD50, is a protein that in humans is encoded by the ''RAD50'' gene. Function The protein encoded by this gene is highly similar to ''Saccharomyces cerevisiae'' Rad50, a protein involved in DNA double- ...
,
Rad51 DNA repair protein RAD51 homolog 1 is a protein encoded by the gene ''RAD51''. The enzyme encoded by this gene is a member of the RAD51 protein family which assists in repair of DNA double strand breaks. RAD51 family members are homologous to t ...
, Rad52, Mnd1, Dmc1, Msh'', and '' Mlh''. This finding suggests that ''Acanthamoeba'' is capable of some form of meiosis and may be able to undergo sexual reproduction. Owing to its ease and economy of cultivation, the Neff strain of ''A. castellanii'', discovered in a pond in
Golden Gate Park Golden Gate Park is an urban park between the Richmond District, San Francisco, Richmond and Sunset District, San Francisco, Sunset districts on the West Side (San Francisco), West Side of San Francisco, California, United States. It is the Lis ...
in the 1960s, has been effectively used as a classic model organism in the field of cell biology. From just 30 L of simple medium inoculated with ''A. castellanii'', about 1 kg of cells can be obtained after several days of aerated culture at room temperature. Pioneered in the laboratory of Edward D. Korn at the
National Institutes of Health The National Institutes of Health (NIH) is the primary agency of the United States government responsible for biomedical and public health research. It was founded in 1887 and is part of the United States Department of Health and Human Service ...
(NIH), many important biological molecules have been discovered and their pathways elucidated using the ''Acanthamoeba'' model. Thomas Dean Pollard applied this model at the NIH,
Harvard Medical School Harvard Medical School (HMS) is the medical school of Harvard University and is located in the Longwood Medical and Academic Area, Longwood Medical Area in Boston, Massachusetts. Founded in 1782, HMS is the third oldest medical school in the Un ...
,
Johns Hopkins University School of Medicine The Johns Hopkins University School of Medicine (JHUSOM) is the medical school of Johns Hopkins University, a Private university, private research university in Baltimore, Maryland. Established in 1893 following the construction of the Johns Ho ...
, and the
Salk Institute for Biological Studies The Salk Institute for Biological Studies is a scientific research institute in the La Jolla community of San Diego, California. The independent, non-profit institute was founded in 1960 by Jonas Salk, the developer of the polio vaccine; among th ...
to discover and characterize many proteins that are essential for cell motility, not only in amoebae, but also in many other eukaryotic cells, especially those of the human nervous and immune systems, the developing embryo, and cancer cells. ''Acanthamoeba'' also has served as a model to study the evolution of certain
G-protein G proteins, also known as guanine nucleotide-binding proteins, are a family of proteins that act as molecular switches inside cells, and are involved in transmitting signals from a variety of stimuli outside a cell to its interior. Their ...
s. This unicellular eukaryote expresses few GPCRs over its cell membrane that serve vital role for the microorganism, structural homology bioinformatics tools have been used to show the presence of a homolog of human M1-muscarinic receptor in ''A. castellanii''. Blocking these muscarinic receptors in past studies has proven to be amoebicidal in Acanthamoeba spp. More recently,
voltage-gated calcium channel Voltage-gated calcium channels (VGCCs), also known as voltage-dependent calcium channels (VDCCs), are a group of voltage-gated ion channels found in the membrane of excitable cells (''e.g.'' muscle, glial cells, neurons) with a permeability to ...
s in ''Acanthamoeba'' spp. (CavAc) have been reported to have similarities with human voltage-gated calcium channels such as TPC-1 and
L-type calcium channel The L-type calcium channel (also known as the dihydropyridine channel, or DHP channel) is part of the high-voltage activated family of voltage-dependent calcium channel. "L" stands for long-lasting referring to the length of activation. This ...
s and respond to Ca-channel blockers such as loperamide. This model microbe has been studied to understand complex neurodegenerative states including Alzheimer's disease. Scientists have isolated a neurotransmitter
acetylcholine Acetylcholine (ACh) is an organic compound that functions in the brain and body of many types of animals (including humans) as a neurotransmitter. Its name is derived from its chemical structure: it is an ester of acetic acid and choline. Par ...
in ''Acanthamoeba'' and the enzymatic machinery needed for its synthesis.


Endosymbionts

''Acanthamoeba'' spp. contain diverse bacterial
endosymbiont An endosymbiont or endobiont is an organism that lives within the body or cells of another organism. Typically the two organisms are in a mutualism (biology), mutualistic relationship. Examples are nitrogen-fixing bacteria (called rhizobia), whi ...
s that are similar to human pathogens, so they are considered to be potential emerging human pathogens. The exact nature of these symbionts and the benefit they represent for the amoebic host still have to be clarified. These include ''
Legionella ''Legionella'' is a genus of gram-negative bacteria, gram-negative bacteria that can be seen using a silver stain or grown in a special media that contains cysteine, an amino acid. It is known to cause legionellosis (all illnesses caused by ''Legi ...
'' and ''Legionella''-like pathogens.


Giant viruses

The
giant viruses A giant virus, sometimes referred to as a girus, is a very large virus, some of which are larger than typical bacteria. All known giant viruses belong to the phylum '' Nucleocytoviricota''. Description While the exact criteria as defined in the s ...
''
Mimivirus ''Mimivirus'' is a genus of giant viruses, in the family ''Mimiviridae''. It is believed that Amoeba serve as their natural hosts. It also refers to a group of phylogenetically related large viruses. In colloquial speech, APMV is more commonly ...
,
Megavirus ''Megavirus'' is a viral genus, phylogenetically related to '' Acanthamoeba polyphaga mimivirus'' (APMV). In colloquial speech, ''Megavirus chilense'' is more commonly referred to as just "Megavirus". Until the discovery of pandoraviruses in 2 ...
'', and ''
Pandoravirus ''Pandoravirus'' is a proposed genus of giant virus, first discovered in 2013. It is the third largest in physical size of any known viral genus, behind Pithovirus and Megaklothovirus. Pandoraviruses have double stranded DNA genomes, with t ...
'' infect ''Acanthamoeba''. Members of the genus ''Acanthamoeba'' are unusual in serving as hosts for a variety of
giant viruses A giant virus, sometimes referred to as a girus, is a very large virus, some of which are larger than typical bacteria. All known giant viruses belong to the phylum '' Nucleocytoviricota''. Description While the exact criteria as defined in the s ...
(that have more than 1000 protein-coding genes; for instance, ''Pandoravirus'', which has about 2500 protein-coding genes in its genome).


Diversity

''Acanthamoeba'' can be distinguished from other genera of amoebae based on morphological characteristics. However, differentiating one species of ''Acanthamoeba'' from another by morphology has proven difficult. Based on
18S rDNA 18S ribosomal RNA (abbreviated 18S rRNA) is a part of the ribosomal RNA in eukaryotes. It is a component of the Eukaryotic small ribosomal subunit (40S) and the cytosolic homologue of both the 12S rRNA in mitochondria and the 16S rRNA in plastid ...
sequencing, known ''Acanthamoeba'' strains can be organized into 12 groups, denoted T1-T12. Most disease-causing isolates belong to type T4. Below is a list of described species of ''Acanthamoeba'', with sequence types noted where known. Species that have been identified in diseased patients are marked with *. *''A. astronyxis'' (Ray & Hayes 1954) Page 1967 * (T7) *''A. byersi'' Qvarnstrom, Nerad & Visvesvara 2013 * *''A. castellanii'' Volkonski 1931 * (T4) 'A. terricola'' Pussard 1964*''A. comandoni'' Pussard 1964 (T9) *''A. culbertsoni'' (Singh & Das 1970) Griffin 1972 * (T10) *''A. divionensis'' Pussard & Pons 1977 (T4) *''A. echinulata'' Pussard & Pons 1977 *''A. gigantea'' Schmöller 1964 *''A. glebae'' (Dobell 1914) *''A. gleichenii'' Volkonsky 1931 *''A. griffini'' Sawyer 1971 (T3) *''A. hatchetti'' Sawyer, Visvesvara & Harke 1977 * (T11) *''A. healyi'' Moura, Wallace & Visvesvara 1992 (T12) *''A. hyalina'' Dobel & O'connor 1921 *''A. jacobsi'' Sawyer, Nerad & Visvesvara 1992 *''A. keratitis'' * *''A. lenticulata'' Molet & Ermolieff-braun 1976 (T3) *''A. lugdunensis'' Pussard & Pons 1977 * (T4) *''A. mauritaniensis'' Pussard & Pons 1977 (T4) *''A. micheli'' Corsaro et al. 2015 *''A. palestinensis'' (Reich 1933) Page 1977 * (T1) *''A. paradivionensis'' Pussard & Pons 1977 (T4) *''A. pearcei'' Nerad et al. 1995 *'' A. polyphaga'' (Puschkarew 1913) Volkonsky 1931 * (T4) *''A. pustulosa'' Pussard & Pons 1977 (T2) *'' A. pyriformis'' (Olive & Stoianovitch 1969) Spiegel & Shadwick 2016 *''A. quina'' Pussard & Pons 1977 * *''A. rhysodes'' (Singh 1952) Griffin 1972 * (T4) *''A. royreba'' Willaert, Stevens & Tyndall 1978 *''A. sohi'' Kyung-il & Shin 2003 *''A. stevensoni'' Sawyer et al. 1993 (T11) *''A. triangularis'' Pussard & Pons 1977 (T4) *''A. tubiashi'' Lewis & Sawyer 1979 (T8)


Etymology

From the
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 ...
''akantha'' (spike/thorn), which was added before "amoeba" (change) to describe this organism as having a spine-like structure (acanthopodia). This organism is now well known as Acanthamoeba, an amphizoic, opportunistic, and nonopportunistic protozoan protist widely distributed in the environment.


See also

* ''Acanthamoeba'' infection * '' Balamuthia mandrillaris''


References


External links


''Acanthamoeba''
Centers for Disease Control and Prevention The Centers for Disease Control and Prevention (CDC) is the National public health institutes, national public health agency of the United States. It is a Federal agencies of the United States, United States federal agency under the United S ...

Video of Acanthamoeba from contact lens keratitis
*

on
Amoeba An amoeba (; less commonly spelled ameba or amœba; : amoebas (less commonly, amebas) or amoebae (amebae) ), often called an amoeboid, is a type of Cell (biology), cell or unicellular organism with the ability to alter its shape, primarily by ...

Eye health and AcanthamoebaAcanthamoeba pictures and illustrations
{{Authority control Amoebozoa genera Discosea Parasitic amoebozoa Taxa described in 1931