• Parasites, Hosts and Diseases
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• v.34 no.1
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• pp.79-86
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• 1996

A strain, KA/S2, isolated from Korean soil and morphologically assigned to Acanthcmoebc cQsteLlcnii, was characterized by isoenzyme analysis , and total proteins profile, End mitochondrial (Mt) DNA restriction fragment length polymorphism (RFLP) , and compared with four reference strains assigned to the species (the authenitic Castellani, Neff, Ma, and Chang strains). It was found that four isoenzyme, total proteins, and Mt DNA RFLP patterns by eight restriction endonucleases of the strain KA/S2 were identical with those of the Neff strain, isolated from soil of California, USA. The Chang strain was unique in its morphology and total protein patterns. Interstrain polymorphisms of isoensyme profiles and Mt DNA RFLP patterns were observed among the Castellani, Neff, Ma, and Chang strains. Mt DNA RFLP was confirmed to be highly appropriate for the strain characterization and identification of Acnnthamoeba spry.

• Parasites, Hosts and Diseases
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• v.44 no.4 s.140
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• pp.321-330
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• 2006

The pathogenic mechanism of granulomatous amebic encephalitis (GAE) and amebic keratitis (AK) by Acanthamoeba has yet to be clarified. Pretense has been recognized to play an important role in the pathogenesis of GAE and AK. In the present study, we have compared specific activity and cytopathic effects (CPE) of purified 33 kDa serine proteinases from Acanthamoeba strains with different degree of virulence (A. healyi OC-3A, A. lugdunensis KA/E2, and A. castelianii Neff). Trophozoites of the 3 strains revealed different degrees of CPE on human corneal epithelial (HCE) cells. The effect was remarkably reduced by adding phenylmethylsulfonylfluoride (PMSF), a serine proteinase inhibitor. This result indicated that PMSF-susceptible proteinase is the main component causing cytopathy to HCE cells by Acanthamoeba. The purified 33 kDa serine proteinase showed strong activity toward HCE cells and extracellular matrix proteins. The purified proteinase from OC-3A, the most virulent strain, demonstrated the highest enzyme activity compared to KA/E2, an ocular isolate, and Neff, a soil isolate. Polyclonal antibodies against the purified 33 kDa serine proteinase inhibit almost completely the proteolytic activity of culture supernatant of Acanthamoeba. In line with these results, the 33 kDa serine proteinase is suggested to play an important role in pathogenesis and to be the main component of virulence factor of Acanthamoeba.

• Parasites, Hosts and Diseases
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• v.36 no.2
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• pp.69-80
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• 1998

Subgenus classification of Acanthcmoeba remains uncertain. Twenty-three reference strains of Acanthnmoeba including 18 (neo)type-strains were subjected for classification at the subgenus level by riboprinting, PCR/RFLP analysis of 185 rRNA gene (rDNA) . On the dendrogram reconstructed on the basis of riboprint analyses, two type- strains (A. astronwxis and A. tubinshi) 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. polestinensis, A. healyi were considered taxonomically valid, but A. pustulosn was regarded as an invalid synonym of A. pclestinensis. Strains of morphological group 2 were classified into 6 subgroups. Among them, A. giulni which has an intron in its 185 rDNA was the most divergent from the remaining strains. Acanthcmoebc ccstellanii Castellani, A. quinc Vil3, A. Iugdunensis L3a. A. poIyphage Jones, A. trinngularis SH621, and A. cqstellanii Ma strains belonged to a subgroup, A. castellanii complex. However, A. quinc and A. Lugnunensis were regarded as synonyms of A. ccstellanii. The Chang strain could be regarded as A. hatchetti. Acanthcmoebo nauritaniensis, A. niuionensis, A. paranivionensis could be considered as synonyms of A. rhwsodes. Neff strain was regarded as A. polyphage rather than as A. castellanii. It is likely that riboprinting can be applied for rapid identification of Acnnthcmoebc isolated from the clinical specimens and environments.

• Parasites, Hosts and Diseases
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• v.37 no.3
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• pp.181-188
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• 1999

We investigated the value of mitochondrial small subunit rRNA gene (mt SSU rDNA) PCR-RFLP as a taxonomic tool for Acanthamoeba isolates with close inter-relationships. Twenty-five isolates representing 20 species were included in the analysis. As in nuclear 18s rDNA analysis, two type strains (A. astronyxis and A. tubiashi) of morphological group 1 diverged earliest from the other strains, but the divergence between them was less than in 18s riboprinting. Acanthamoeba griffini of morhological group 2 branched between pathogenic (A. culbertsoni A-1 and A. healyi OC-3A) and nonpathogenic (A.palestinensis Reich, A. pustulosa GE-3a, A. royreba Oak Ridge, and A lenticulata PD2S) strains of morphological group 3. Among the remaining isolates of morphological group 2, the Chang strain had the identical mitochondrial riboprints as the type strain of A. hatchetti. AA2 and AA1, the type strains of A. divionensis and A. paradivionensis, respectively, had the identical riboprints as A. quina Vil3 and A. castellanii Ma. Although the branching orders of A. castellanii Neff, A. polyphaga P23, A. triangularis SH621, and A. lugdunensis L3a were different from those in 18S riboprinting analysis, the results obtained from this study generally coincided well with those from 18S riboprinting. Mitochondrial riboprinting may have an advantage over nuclear 18S rDNA riboprinting beacuse the mt SSU rDNAs do not seem to have introns that are found in the 18S genes of Acanthamoeba and that distort phylogenetic analyses.