Molecular Phylogeny of Acanthamoeba

Abstract

After morphological grouping of Acanthamoeba by Pussard and Pons, phylogeny of the genus has been always a big topic to the researchers. Because of the variability of morphological characteristics, unchangeable and stable characters have been investigated for phylogenic criteria. Isoenzyme and mitochondrial DNA RFLP (Mt DNA RFLP) analyses revealed different patterns among strains assigned to a same species. Therefore, these characteristics would be considered as tools for strain discrimination than species identification. The most recently developed and the most promising method is the sequence analysis of 18s ribosomal RNA coding DNA (18s rDNA). The phylogenic tree based on comparison of 18s rDNA sequences distinguished the 3 morphological groups of Acanthamoeba and divided them into 12 unique sequence types (T1-T12 genotypes). Most clinical and environmental isolates belonged to the morphological group II and the genotype T4. In the Republic of Korea, 2 strains of Acanthamoeba, YM-2 and YM-3, were first isolated from the environment in 1974. However, phylogenic identification of Korean Acanthamoeba isolates from human infections or the environment were tried from the late 1990s. By RFLP analysis or total sequence analysis of 18s rDNA revealed that almost all clinical isolates including the one from a suspicious granulomatous amebic encephalitis patient belonged to the genotype T4. A large number of environmental isolates from contact lens storage cases, tapped water, and ocean sediments also belonged to the genotype T4. Almost identical strain characteristics, such as Mt DNA RFLP pattern of environmental isolates, with the clinical isolates could make a simple conclusion that most environmental isolates might be a potential keratopathogen.

Molecular detection of free-living amoebae from Namhangang (southern Han River) in Korea

“…In Korea, Acanthamoeba spp. has been detected in amoeba-contaminated tap water in damaged water pipes and in several AK patients 43,44 .…”

Isolates from ancient permafrost help to elucidate species boundaries in Acanthamoeba castellanii complex (Amoebozoa: Discosea)

“…The distinctiveness of different clades inside type T4 has begun to manifest itself since the first works on Acanthamoeba rDNA diversity (Gast et al , 1996;Stothard et al , 1998;Chung et al , 1998;Booton et al , 2002;Kong, 2009;Fuerst et al , 2015;Martín-Pérez et al , 2017). Subtypes T4 C , T4 D , T4 E , T4 F , and T4 Neff , when represented by several sequences, were usually well-supported, while T4 B was sometimes mixed with T4 A , and the latter mostly paraphyletic.…”

“…T4 D sequences formed a clade sister to mixed T4 A/B clade. Kong (2009) using a smaller dataset identified five 16S clades, namely the deepest branching T4 C , the next branching T4 D , then T4 Neff , and the last branching T4 A/B , which in turn consisted of two clusters: the one containing, among others, Ma and Castellani strains and another one containing A. lugdunensis L3a. Finally, Rahman et al (2013) adding 13 T4 rns sequences obtained generally the same nine clades as Ledee et al (2003) inside T4 subtype.…”

“…Here belong the type strains of most of the species described on the basis of morphology, including the generic type, Acanthamoeba castellanii (Douglas, 1930) and thoroughly redescribed by Page (1967) Acanthamoeba polyphaga (Puschkarew, 1913). Due to the plastic nature of characters by which T4 species are differentiated and unclear synonymy, some authors prefer to designate this type " A. castellanii species complex" (Kong, 2009;Corsaro et al , 2017). Therefore, reconciling molecular with morphological data inside T4 is essential for the system of the genus as a whole, which means establishing a genus-specific species concept integrating phenotypic and genotypic taxonomic markers (Boenigk et al , 2012).…”

Estudio del papel de las amebas de vida libre como reservorio de Helicobacter pylori y otras bacterias patógenas en aguas y alimentos mediante técnicas moleculares

“…Su tamaño varía entre 13-20 µm y cambia entre especies. (Kong, 2009) En el caso de B. mandrillaris, el trofozoito se mueve lentamente comparado con otras FLA, con una velocidad estimada de 0,15 µm/s (Schuster et al, 2003). (Visvesvara et al, 2007).…”