• 대한의생명과학회지
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• 제17권1호
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• pp.7-12
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• 2011

Free-living amoebae ingest several kinds of bacteria. In other words, the bacteria can survive within free-living amoeba. To determine how Escherichia coli K1 isolate causing neonatal encephalitis and non-pathogenic K12 interact with free-living amoebae, e.g., Acanthamoeba castellanii (T1), A. astronyxis (T7), Naegleria fowleri, association, invasion and survival assays were performed. To understand pathogenicity of free-living amoebae, in vitro cytotoxicity assay were performed using murine macrophages. T1 destroyed macrophages about 64% but T7 did very few target cells. On the other hand, N. fowleri which needed other growth conditions rather than Acanthamoeba destroyed more than T1 as shown by lactate dehydrogenase (LDH) release assay. In association assays for E. coli binding to amoebae, the T7 exhibited significantly higher association with E. coli, compared with the T1 isolates (P<0.01). Interestingly, N. fowleri exhibited similar percentages of association as T1. Once E. coli bacteria attach or associate with free-living amoeba, they can penetrate into the amoebae. In invasion assays, the K1 (0.67%) within T1 was observed compared with K12 (0%). E. coli K1 and K12 exhibited high association with N. fowleri and bacterial CFU. To determine the fate of E. coli in long-term survival within free-living amoebae, intracellular survival assays were performed by incubating E. coli with free-living amoebae in PBS for 24 h. Intracellular E. coli K1 within T1 (2.5%) and T7 (1.8%) were recovered and grown, while K12 were not found. N. fowleri was not invaded and here it was not recovered.

• Parasites, Hosts and Diseases
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• 제37권3호
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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.

• Parasites, Hosts and Diseases
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• 제34권2호
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• pp.127-134
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• 1996

형태학적으로 카스텔라니가시아메바 혹은 대식가시아메바로 동정된 12 분리주들과 쿨버트손가시 아메바. 힐리가시아메바(Aconthomoeba hedwi) 팔레스타인가시아메바(A. plestinenis) 별가시아메바의 small subunitribosomal RNA유전자(ssu rDNA) 중 conserved region을 PCRR 증폭하여 제한효노절단부위를 비교하떴다. 별가시아메바의 PCR증폭 산물의 크기는 1.170 bp였고 나머지 분기주들의 것은 910-930 bp 사이였다 카스텔라너가시아메바로 분류건 여섯 주간의 추정 염기치찬율의 평근은 9.BPg였고. 대식가시아떼바로 분류된 분리주간의 그 평근은 9 6U였다. 카스텔 라니가시아메바로 분류된 여섯 분리주들 사이의 최대 염기치환율은 Chang주와 Ma주 사이의 (7 3%)였고 대식가시아메바로 분류된 여섯 분리주간의 최대 염기치환율은 1A/S3주와 KA/S7주 사이의 (16.1%)였다. 이들 종내 최대 염기치환율은 Castellani주 혹은 CCAP 1501/12g주와 KA/S3 주 사이에거 나타난 카스텔라니가시아메바와 대식가시아떼바간의 종간 최소 염기치환율(2.6%)보 다 횔씬 컸나. 쿨버트손가시아메바. 힐리가시아메바 팔레스타인가시아메바 및 별가시아메바의 PCR-RFLP 양상은 카스텔라니가시아메바 또는 대식가시아메바로 동정된 분리주들의 것들과 그리 고 강호간에서도 높은 염기치환율(평균 23 6%)을 보였다. 이상의 성적으로 미루어 보아 가시아메바속의 분류는 재평가 해 보아야 할 건으로 생각된다 A. healyi와 A. palestinensis의 우리말 이름을 각각 힐리가시아메바와 팔레스타인가시아메바로 제안한다.