Isolation and identification of Acanthamoeba strains from soil and tap water in Yanji, China.

BACKGROUND: Members of the genus Acanthamoeba are widely distributed throughout the world, and some of them are considered pathogenic, as they are capable of causing corneal and central nervous system diseases. In this study, we isolated Acanthamoeba strains from soil and tap water in Yanji, China. METHODS: We identified four strains of Acanthamoeba (CJY/S1, CJY/S2, CJY/S3, and CJY/W1) using mitochondrial DNA restriction fragment length polymorphism (mtDNA RFLP) analysis. Nuclear 18S rDNA sequences were used for phylogenetic analysis and species identification. RESULTS: Genotypic characterization of the isolates showed that they belonged to genotypes T4 (CJY/S1 and CJY/S2), T5 (CJY/S3), and T16 (CJY/W1). Sequence differences between CJY/S1 and Acanthamoeba castellanii Neff, CJY/S2 and Acanthamoeba KA/E7, and CJY/S3 and Acanthamoeba lenticulata 68-2 were 0.31, 0.2, and 0.26%, respectively. 18S ribosomal deoxyribonucleic acid (rDNA) of CJY/W1 had 99% sequence identity to that of Acanthamoeba sp. U/H-C1. Strains CJY/S1 and CJY/S2, isolated from soil, had similar mtDNA RFLP patterns, whereas strain CJY/W1, isolated from tap water, displayed a different pattern. CONCLUSIONS: To the best of our knowledge, this is the first report on the identification of genotypes T4, T5, and T16 from environmental sources in Yanji, China.

[Progress on classification and identification of Acanthamoeba].

As a pathogenic free-living amoeba, Acanthamoeba is easy to be recognized at the genus level, but difficult to identify at species level on the morphological basis. This review summarizes the methods for Acanthamoeba species classification and identification.

[Sequence analysis of 16S rDNA gene of endosymbiont of Acanthamoeba sp. CB/S1 isolated from soil].

The endosymbiont of Acanthamoeba sp. CB/SI was identified by orcein-carmine staining and 16S rDNA sequence analysis. The endosymbiont bacteria were rod-shaped and darkly stained, and irregularly localized within the cytoplasm. The length of the 16S rDNA was 1534 bp and its DNA sequence was closely related to those of Candidatus Amoebophilus asiaticus and Acanthamoeba sp. KA/E21 with 98% homology. Phylogenetic analysis showed that the endosymbiont of CB/SI, the endosymbiont of KA/E21, Candidatus Amoebophilus asiaticus, the endosymbiont of Ixodes scapularis, and the endosymbiont of Encarsia pergandiella constitute a monophyletic lineage in phylogenetic tree.

[In vitro effect of allitridium on the ultrastructure of Acanthamoeba castellanii].

Acanthamoeba castellanii (T4) was cultured with different concentrations of allitridium for 24 hours, and examined by transmission electron microscope. The results showed that the ultrastructure of Acanthamoeba trophozoites was destroyed gently at concentration of 50 microg/ml allitridium and seriously destroyed under the concentration of 500 microg/ml, indicating that allitridium is effective in destroying Acanthamoeba.

Tissue parasitic helminthiases are prevalent at Cheongjin, North Korea.

We investigated a small-scale serological survey to screen tissue-parasitic helminthiases of North Koreans as one of research programs for re-unification of Korea. Soil-transmitted helminthiases were found highly prevalent among North Korean residents at the border with China. ELISA using 4 tissue-parasitic helminth antigens was applied to 137 residents living in Cheongjin-shi, Hamgyeongbuk-do, North Korea and 133 female refugees in South Korea in 2004-2005. Among a total of 270 samples, 31 (11.5%), 25 (9.3%), and 11 (4.1%) were positive for specific IgG antibodies to antigens of Clonorchis sinensis, Taenia solium metacestode, and sparganum, respectively. The overall positive rate was 21.5%; 38.2% in males and 15.8% in females. The present finding suggests that tissue parasites, such as C. sinensis, T. solium metacestode and sparganum are highly prevalent in some limited areas of North Korea. These foodborne tissue-parasitic helminthiases should be considered for future control measures of parasitic diseases in North Korea.

[Genetic identification of Acanthamoeba sp. CJY/S1 and CJY/S2 isolated from soil].

Two isolates of Acanthamoeba sp. CJY/SI and CJY/S2 were received from soil in Yanji of Jilin Province. Full 18S rDNA gene was amplified using PCR, cloned and sequenced. The results were analyzed by software Clustal X. The full length of CJY/S1 and CJY/S2 is 2255 bp and 2252 bp respectively, both belong to T4 genotype.