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The Journal of Protozoology Feb 1978A new species of Acanthamoeba was isolated from a culture of an established line of human choriocarcinoma cells. The identification of this strain, originally called the...
A new species of Acanthamoeba was isolated from a culture of an established line of human choriocarcinoma cells. The identification of this strain, originally called the Oak Ridge strain, and the establishment of a new species for it were based on morphologic, serologic, and immunochemical studies. In general, the structure of the trophozoite did not differ significantly from that of other species of Acanthamoeba, except that a body which more closely resembled a centriole than material described previously as centriolar satellites was observed in trophozoites examined with the electron microscope. The dimensions of the trophozoite were the smallest among the species of Acanthamoeba. The cyst was typical of the genus, but differed from those of other species by its smaller size and the presence of numerous ostioles. Studies of the Oak Ridge strain by immunofluorescence using antisera developed against the isolate and Acanthamoeba culbertsoni, A. castellanii, A. polyphaga, A. rhysodes, A. astronyxis, and A. palestinensis revealed the antigenic uniqueness of the Oak Ridge strain. It was demonstrated by immunoelectrophoretic analyses of the soluble proteins of the Oak Ridge strain that shared approximately 1/2 of its antigenic structure with A. castellanii and A. culbertsoni. The antigenic differences of the isolate from other species of Acanthamoeba were deduced from comparison of the antigenic constitution of these species and the Oak Ridge strain with A. culbertsoni and A. castellanii. Although the strain was initially recognized by its cytopathogenicity for cultures, it did not produce acute infections in mice after intranasal inoculation of 1 X 10(4) ameba/mouse. The foregoing results constituted the basis for the establishment of the Oak Ridge strain as a new species, A. royreba sp. n., in the genus Acanthamoeba.
Topics: Amoeba; Animals; Antigens; Cell Line; Choriocarcinoma; Female; Humans; Immunoelectrophoresis; Mice; Microscopy, Electron; Pregnancy
PubMed: 566323
DOI: 10.1111/j.1550-7408.1978.tb03854.x -
The Journal of Protozoology May 1980Defined media are described that support 14-20 h generation times for Acanthamoeba castellanii and A. rhysodes in monolayer cultures. The media differ in minor ways from...
Defined media are described that support 14-20 h generation times for Acanthamoeba castellanii and A. rhysodes in monolayer cultures. The media differ in minor ways from previously described media, but the growth rates are greatly improved over previously reported values. Maximum growth rates were observed for A. castellanii in a complex medium containing 21 amino acids, but near-maximum rates could be achieved in relatively simple media containing 9 amino acids. Growth occurred with 6 amino acids, as reported by others, but generation times exceeded 30 h. Amitosis was a common problem during early subcultures in defined media, defined media by glucose and acetate starvation. The rate of encystment varied with cell density at the time of starvation and was optimal at initial densities of 400-800 amebae/mm2.
Topics: Acetates; Amino Acids; Amoeba; Animals; Cell Division; Culture Media; Glucose; Kinetics
PubMed: 7400997
DOI: 10.1111/j.1550-7408.1980.tb04684.x -
The Journal of Eukaryotic Microbiology 1996Classification of Acanthamoeba at the subgenus level has been problematic, but increasing reports of Acanthamoeba as an opportunistic human pathogen have generated an...
Classification of Acanthamoeba at the subgenus level has been problematic, but increasing reports of Acanthamoeba as an opportunistic human pathogen have generated an interest in finding a more consistent basis for classification. Thus, we are developing a classification scheme based on RNA gene sequences. This first report is based on analysis of complete sequences of nuclear small ribosomal subunit RNA genes (Rns) from 18 strains. Sequence variation was localized in 12 highly variable regions. Four distinct sequence types were identified based on parsimony and distance analyses. Three were obtained from single strains: Type T1 from Acanthamoeba castellanii V006, T2 from Acanthamoeba palestinensis Reich, and T3 from Acanthamoeba griffini S-7. T4, the fourth sequence type, included 15 isolates classified as A. castellanii, Acanthamoeba polyphaga, Acanthamoeba rhysodes or Acanthamoeba sp., and included all 10 Acanthamoeba keratitis isolates. Interstrain sequence differences within T4 were 0%-4.3%, whereas differences among sequence types were 6%-12%. Branching orders obtained by parsimony and distance analyses were inconsistent with the current classification of T4 strains and provided further evidence of a need to reevaluate criteria for classification in this genus. Based on this report and others in preparation, we propose that Rns sequence types provide the consistent quantititive basis for classification that is needed.
Topics: Acanthamoeba; Animals; Base Sequence; DNA, Protozoan; DNA, Ribosomal; Genetic Heterogeneity; Humans; Molecular Sequence Data; Phylogeny; RNA, Ribosomal, 18S
PubMed: 8976608
DOI: 10.1111/j.1550-7408.1996.tb04510.x -
The Korean Journal of Parasitology Jun 1998Subgenus classification of Acanthamoeba remains uncertain. Twenty-three reference strains of Acanthamoeba including 18 (neo)type-strains were subjected for...
Subgenus classification of Acanthamoeba remains uncertain. Twenty-three reference strains of Acanthamoeba including 18 (neo)type-strains were subjected for classification at the subgenus level by riboprinting. PCR/RFLP analysis of 18S rRNA gene (rDNA). On the dendrogram reconstructed on the basis of riboprint analyses, two type-strains (A. astronyxis and A. tubiashi) of morphological group 1 diverged early from the other strains and were quite distinct from each other. Four type-strains of morphological group 3, A. culbertsoni, A. palestinensis, A. healyi were considered taxonomically valid, but A. pustulosa was regarded as an invalid synonym of A. palestinensis. Strains of morphological group 2 were classified into 6 subgroups. Among them, A. griffini which has an intron in its 18S rDNA was the most divergent from the remaining strains. Acanthamoeba castellanii Castellani, A. quina Vil3, A. lugdunensis L3a, A. polyphaga Jones, A. triangularis SH621, and A. castellanii Ma strains belonged to a subgroup, A. castellanii complex. However, A. quina and A. lugdunensis were regarded as synonyms of A. castellanii. The Chang strain could be regarded as A. hatchetti. Acanthamoeba mauritaniensis, A. divionensis, A. paradivionensis could be considered as synonyms of A. rhysodes. Neff strain was regarded as A. polyphaga rather than as A. castellanii. It is likely that riboprinting can be applied for rapid identification of Acanthamoeba isolated from the clinical specimens and environments.
Topics: Acanthamoeba; Animals; DNA, Protozoan; Polymerase Chain Reaction; Polymorphism, Restriction Fragment Length; RNA, Protozoan; RNA, Ribosomal, 18S
PubMed: 9637824
DOI: 10.3347/kjp.1998.36.2.69 -
Scientific Reports Jul 2020Multinuclearity is a widespread phenomenon across the living world, yet how it is achieved, and the potential related advantages, are not systematically understood. In...
Multinuclearity is a widespread phenomenon across the living world, yet how it is achieved, and the potential related advantages, are not systematically understood. In this study, we investigate multinuclearity in amoebae. We observe that non-adherent amoebae are giant multinucleate cells compared to adherent ones. The cells solve their multinuclearity by a stretchy cytokinesis process with cytosolic bridge formation when adherence resumes. After initial adhesion to a new substrate, the progeny of the multinucleate cells is more numerous than the sibling cells generated from uninucleate amoebae. Hence, multinucleate amoebae show an advantage for population growth when the number of cells is quantified over time. Multiple nuclei per cell are observed in different amoeba species, and the lack of adhesion induces multinuclearity in diverse protists such as Acanthamoeba castellanii, Vermamoeba vermiformis, Naegleria gruberi and Hartmannella rhysodes. In this study, we observe that agitation induces a cytokinesis delay, which promotes multinuclearity. Hence, we propose the hypothesis that multinuclearity represents a physiological adaptation under non-adherent conditions that can lead to biologically relevant advantages.
Topics: Acanthamoeba castellanii; Cell Culture Techniques; Cell Nucleus; Cytokinesis; Microscopy, Electron, Scanning
PubMed: 32694508
DOI: 10.1038/s41598-020-68694-9 -
Bio Systems 1985Isoenzyme electrophoresis of three different enzyme systems was used to compare 71 strains assigned to the 15 currently recognized species of Acanthamoeba. A... (Comparative Study)
Comparative Study
Isoenzyme electrophoresis of three different enzyme systems was used to compare 71 strains assigned to the 15 currently recognized species of Acanthamoeba. A phylogenetic (cladistic) analysis of the zymograms indicated an arrangement of strains in 15 distinguishable lineages, but not all corresponding to current taxonomic assignments. Five of the groups corresponded to the recognized species A. castellanii, A. culbertsoni, A. griffini, A. lenticulata and A. royreba. But none of these groups consisted of only strains which had been previously assigned to each respective species. The type-equivalent strains for two species, A. hatchetti and A. tubiashi, were not closely aligned to any other strain and thus are considered to be monotypic. Strains of A. triangularis, A. astronyxis and A. palestinensis occurred together in a single group suggesting possible synonymy; however, on morphologic criteria, the strains assigned to these species are readily distinguishable. Strains assigned to A. polyphaga and A. rhysodes were interspersed throughout the other species groups. The strains of these two species were either misidentified or the species could not be recognized. Two groups previously not recognized as unique formed distinctive clusters which could be considered as new species. The analysis also made it possible to place strains which had previously been identified only to genus into species complexes. These results therefore suggest that previous criteria which have been used to classify Acanthamoeba are not adequate for fully resolving taxa at the species level.
Topics: Amoeba; Animals; Electrophoresis; Isoenzymes; Phylogeny; Species Specificity
PubMed: 4084681
DOI: 10.1016/0303-2647(85)90039-5 -
International Journal of Medical... Aug 2005The virulence-associated SpvB protein of Salmonella enterica is a mono (ADP-ribosyl)transferase defined to target mammalian actin. Exposure of Acanthamoeba rhysodes cell...
The virulence-associated SpvB protein of Salmonella enterica is a mono (ADP-ribosyl)transferase defined to target mammalian actin. Exposure of Acanthamoeba rhysodes cell lysate with SpvB and [32P]nicotinamide adenine dinucleotide (NAD) was here observed to result in labeling of a protein of 43 kDa that subsequently was identified as actin by immunoprecipitation. In parallel, ADP-ribosylation promoted degradation of the protozoan actin. SpvB-mediated actin degradation occurred in the presence of the serine protease inhibitor phenylmethylsulfonylfluoride (PMSF), but was inhibited upon addition of novobiocin, an inhibitor of mono (ADP-ribosyl)transferase activity, or upon addition of EDTA. Infection of A. rhysodes with SpvB-proficient S. enterica serovariant Dublin resulted in cytotoxicity and in characteristic SpvB-mediated actin degradation. Cells infected with SpvB-deficient bacteria showed a decrease in cytotoxicity and lack of actin degradation. Combining these results show that SpvB formally can ADP-ribosylate A. rhysodes actin but that the protozoan cell has the capacity to subsequently degrade ADP-ribosyl-tagged actin. These observations illustrate a hitherto undefined consequence of actin modification, and define a new pathway in the cellular actin dynamics.
Topics: ADP Ribose Transferases; Actins; Adenosine Diphosphate Ribose; Amoeba; Animals; Salmonella enterica; Virulence Factors
PubMed: 16128395
DOI: 10.1016/j.ijmm.2005.04.008 -
Parasitology Research Mar 2009We present a novel and simple technique for storing live Acanthamoeba for long periods of time. The amoebae are maintained at refrigerator temperatures in a...
We present a novel and simple technique for storing live Acanthamoeba for long periods of time. The amoebae are maintained at refrigerator temperatures in a peptone-yeast extract-glucose (PYG) medium normally used for cultivation. Using this method, we obtained survival rates of at least 4 years for Acanthamoeba polyphaga and 3 years for Acanthamoeba castellanii and Acanthamoeba rhysodes. Advantages of this storage method are: (1) it is quick and simple, (2) inexpensive, (3) does not require encystment before storage, (4) resuscitation of cysts can be achieved within a week of culture in PYG medium at 27 degrees C, and does not require co-culture with bacteria or any special equipment.
Topics: Acanthamoeba; Acanthamoeba castellanii; Animals; Culture Media; Parasitology; Preservation, Biological; Refrigeration; Time Factors
PubMed: 19089450
DOI: 10.1007/s00436-008-1304-x -
International Journal For Parasitology Jun 2000Three stresses, viz heat, oxidative and pH shocks, were applied to cultures of three species of Acanthamoeba, free-living Acanthamoeba rhysodes and pathogenic...
Three stresses, viz heat, oxidative and pH shocks, were applied to cultures of three species of Acanthamoeba, free-living Acanthamoeba rhysodes and pathogenic Acanthamoeba castellanii and Acanthamoeba culbertsoni. The effect of each stressor on trophozoite integrity was evaluated by the amount of heat shock protein (HSP)60 and HSP70 produced and by exclusion of 0.2% Congo Red. HSP60 and HSP70 levels were estimated using Western blotting and subsequent densitometric analyses. Unstimulated trophozoites from A. rhysodes produced the lowest background levels of HSP60 and HSP70 and were the amoebae most affected by (mammalian-type) stresses as judged by their enhanced HSP production and decreased viability upon exposure to such conditions. In contrast, unstimulated Acanthamoeba of the pathogenic variety had relatively high background levels of test HSPs and seemed undisturbed by the types of stresses they must deal with when entering their hosts. These studies suggest that high HSP levels in amphizoic acanthamoebae may indicate their involvement in (i) tolerance induction to hosts' stressors and/or (ii) in species' virulence.
Topics: Acanthamoeba; Animals; Antibodies, Monoclonal; Blotting, Western; Chaperonin 60; Congo Red; Electrophoresis, Polyacrylamide Gel; HSP70 Heat-Shock Proteins; Hot Temperature; Hydrogen Peroxide; Hydrogen-Ion Concentration; Image Processing, Computer-Assisted; Oxidative Stress
PubMed: 10899527
DOI: 10.1016/s0020-7519(00)00060-6 -
The Journal of Histochemistry and... Sep 1978The DNA content of five species of Acanthamoeba was determined by flow microfluorometry. Acanthamoeba castellanii (AC-30), acanthamoeba polyphaga (APG and P-23),...
The DNA content of five species of Acanthamoeba was determined by flow microfluorometry. Acanthamoeba castellanii (AC-30), acanthamoeba polyphaga (APG and P-23), acanthamoeba rhysodes, acanthamoeba culbertsoni (A-1), and acanthamoeba royreba were grown in a casitone based medium 24-48 HR. The trophozoites were harvested, and evaluated for DNA-bound fluorescence. All species tested has DNA values between 2.0-5.0 pg/cell. These results placed DNA/cell values of Acanthamoeba slightly lower than DNA/cell values of other eucaryotic cells and much lower than Amoeba proteus values. These results indicate that FMF may be a useful adjunct in distinguishing Acanthamoeba cells from either eucaryotic cells or some other amoeba. However, differences in DNA/cell between species of Acanthamoeba are small and would not be useful in identification of species.
Topics: Amoeba; Animals; Anura; Chickens; Cytological Techniques; DNA; Erythrocytes; Fluorometry; HeLa Cells; Humans; Species Specificity; Urodela
PubMed: 361883
DOI: 10.1177/26.9.361883