Full-text resources of PSJD and other databases are now available in the new Library of Science.
Visit https://bibliotekanauki.pl
Preferences help
enabled [disable] Abstract
Number of results

Results found: 4

Number of results on page
first rewind previous Page / 1 next fast forward last

Search results

help Sort By:

help Limit search:
first rewind previous Page / 1 next fast forward last
PL
Strains of the genus Acanthamoeba are usually assigned to sequence types or genotypes according to pair-wise similarity values of the nuclear gene for the small subunit of ribosomal RNA. This classification system was established by comparing full or nearly full gene sequences, > 2000 bp. For practical reasons, diagnostic fragments of smaller lengths have been identified and used for rapid and economic identification of large number of strains. While the use of these small fragments in diagnostics applications remains valid when and only if the reference full sequence-type is available, we contest their use to identify and describe new genotypes. We report herein the case of a new genotype described on the basis of solely a small partial sequence and discuss the poor reliability of this fragment to correctly infer phylogenetic relationships, and its limits in the description of new genotypes of Acanthamoeba.
PL
Some amoebae were recovered from freshwater samples on agar plates. Due to a fungal contamination tightly associated with these amoebae, it was impossible to correctly characterize them on a morphological base, but sequences of the small subunit ribosomal RNA gene (SSU rDNA) were successfully obtained from three strains. Phylogenetic analysis performed on these SSU rDNA allowed to identify these amoebae as members of a new lineage, related to the Dermamoebida, which includes also several other environmental SSU sequences.
PL
The genus Sappinia belongs to the family Thecamoebidae within the Discosea (Amoebozoa). For long time the genus comprised only two species, S. pedata and S. diploidea, based on morphological investigations. However, recent molecular studies on gene sequences of the small subunit ribosomal RNA (SSU rRNA) gene revealed a high genetic diversity within the genus Sappinia. This indicated a larger species richness than previously assumed and the establishment of new species was predicted. Here, Sappinia platani sp. nov. (strain PL-247) is described and ultrastructurally investigated. This strain was isolated from the bark of a sycamore tree (Koblenz, Germany) like the re-described neotype of S. diploidea. The new species shows the typical characteristics of the genus such as flattened and binucleate trophozoites with a differentiation of anterior hyaloplasm and without discrete pseudopodia as well as bicellular cysts. Additionally, the new species possesses numerous endocytobionts and dictyosomes. The latter could not be found in previous EM studies of the genus Sappinia. Standing forms, a character of the species S. pedata, could be formed on older cultures of the new species but appeared extremely seldom. A loose layer of irregular, bent hair-like structures cover the plasma membrane dissimilar to the glycocalyx types as formerly detected in other Sappinia strains.
PL
A thermophilic strain of Naegleria clarki, isolated from a pond, has previously been investigated for its peculiarity to host a cytoplasmic symbiont, which causes a loss of the ability to form cysts. This endosymbiont, called Pcb, was itself infected by a phage, and exhibited chlamydia-like features resembling to another symbiont of Naegleria previously described as Protochlamydia naegleriophila. We report in this study, the results of amoeba host range and 16S rDNA molecular phylogeny of this strain, showing that Pcb is a new strain of the Naegleria endosymbiont chlamydial species Protochlamydia naegleriophila (Chlamydiae: Parachlamydiaceae).
first rewind previous Page / 1 next fast forward last
JavaScript is turned off in your web browser. Turn it on to take full advantage of this site, then refresh the page.