Molecular characterization of bacterial endosymbionts of Acanthamoeba isolates from infected corneas of Korean patients.
The endosymbionts of 4 strains of Acanthamoeba (KA/E9, KA/E21, KA/E22, and KA/E23) isolated from the infected corneas of Korean patients were characterized via orcein stain, transmission electron microscopic examination, and 16S rDNA sequence analysis. Double membrane-bound, rod-shaped endosymbionts were distributed randomly throughout both the trophozoites and cysts of each of Acanthamoeba isolates. The endosymbionts of KA/E9, KA/E22, and KA/E23 were surrounded by electron-translucent areas. No lacunae-like structures were observed in the endosymbionts of KA/E21, the bacterial cell walls of which were studded with host ribosomes. Comparative analyses of the 16S rDNA sequences showed that the endosymbionts of KA/E9, KA/E22 and KA/E23 were closely related to Caedibacter caryophilus, whereas the KA/E21 endosymbiont was assigned to the Cytophaga-Flavobacterium-Bacteroides (CFB) phylum. In the 4 strains of Acanthamoeba, the hosts of the endosymbionts were identified as belonging to the Acanthamoeba castellanii complex, which corresponds to the T4 genotype. Acanthamoeba KA/E21 evidenced characteristics almost identical to those of KA/E6, with the exception of the existence of endosymbionts. The discovery of these endosymbionts from Acanthamoeba may prove essential to future studies focusing on interactions between the endosymbionts and the amoebic hosts.
Xuan
Ying-Hua
YH
Department of Parasitology, Kyungpook National University School of Medicine, Taegu 700-422, Korea.
Yu
Hak Sun
HS
Jeong
Hae Jin
HJ
Seol
Sung-Yong
SY
Chung
Dong-Il
DI
Kong
Hyun-Hee
HH
D000048:Acanthamoeba / Q000235:genetics / Q000302:isolation & purification / Q000382:microbiology*; D015823:Acanthamoeba Keratitis / Q000382:microbiology* / Q000469:parasitology*; D000818:Animals; D001419:Bacteria / Q000235:genetics* / Q000302:isolation & purification; D001483:Base Sequence; D003315:Cornea / Q000382:microbiology / Q000469:parasitology*; D004272:DNA, Mitochondrial / Q000235:genetics; D006801:Humans; D007723:Korea; D046529:Microscopy, Electron, Transmission / Q000379:methods; D010078:Oxazines / Q000378:metabolism; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012337:RNA, Ribosomal, 18S / Q000235:genetics; D013559:Symbiosis
D004272:DNA, Mitochondrial; D010078:Oxazines; D012336:RNA, Ribosomal, 16S; D012337:RNA, Ribosomal, 18S; C002313:PAcein