Biology subjects

Rueckert, S.

Publications and source records attributed to Rueckert, S..

3 recordsLinked to original sources

bioRxiv2026

The Leray-XT COI primer pair is not suitable for observing ciliates and radiolarians

The Leray-XT primer pair has been widely used to amplify the mitochondrial cytochrome c oxidase subunit I (COI) gene from animals. In some marine metabarcoding studies, protists have also been amplified and sequenced using these primers. Here, we ask if the Leray-XT COI primer pair is suitable for observing ciliates and radiolarians, which are numerically and ecologically important components of marine protistan communities. We show that while there are sufficient COI reference sequences for ciliates in NCBI for taxonomic assignments, there are currently only two COI reference sequences for radiolarians. Using in-silico analyses, we additionally show that while the reverse primer Leray-XT primer can bind and potentially amplify both ciliates and radiolarians, the forward primer cannot bind to either taxon. These results show that the Leray-XT primer pair is not suitable for observing ciliates and radiolarians, although it may be useful for observing other marine protistan taxa.

microbiology↗

bioRxiv2024

Genetic and morphological characterization of Metacollinia emscheri n. sp., a novel sanguicolous apostome ciliate of the freshwater amphipods Gammarus pulex and G. fossarum

We describe a novel sanguicolous parasitic ciliate, Metacollinia emscheri n. sp., found in the freshwater amphipods Gammarus pulex and G. fossarum. This ciliate infected up to 20% of the amphipods collected in a German stream catchment, the Boye, a tributary of the river Emscher. The ciliate showed morphological characteristics fitting the genus Metacollinia. Different life stages of variable size occurred simultaneously in the hemocoel throughout the hosts body. The tomont had 40-47 slightly spiraled kineties, a non-ciliated cortical band, a large macronucleus, and contractile vacuoles arranged in rows or scattered throughout the cytoplasm. The protomites/tomites with nine somatic kineties presented evidence of the buccal kineties x, y, and z reminiscent of those of the order Foettingeriida. Phylogenetic analyses of the 18S rRNA and COI regions confirm the ciliate placement in the Collinidae and a close relatedness to the type species of the genus Metacollinia, Metacollinia lucensis. Hence, we formally describe this parasite as Metacollinia emscheri n. sp. The systemic infections observed in histological preparations and the pathogenicity of Metacollinia emscheri n. sp. suggest that this parasite might influence host population dynamics. Given the ecological importance of amphipods as keystone species in freshwater ecosystems, an outbreak of this parasite might indirectly impact ecosystem functioning.

ecology↗

bioRxiv2017

Persistent patterns of high alpha and low beta diversity in tropical parasitic and free-living protists

Animal and plant communities in tropical rainforests are known to have high alpha diversity within forests, but low beta diversity between forests. By contrast, it is unknown if the microbial protists inhabiting the same ecosystems exhibit similar biogeographic patterns. To evaluate the biogeographies of soil protists in three lowland Neotropical rainforests using metabarcoding data, we estimated taxa-area and distance-decay relationships for three large protist taxa and their subtaxa, at both the OTU and phylogenetic levels, with presence-absence and abundance based measures, and compared the estimates to null models. High local alpha and low regional beta diversity patterns were persistently found for both the parasitic Apicomplexa and the free-living Cercozoa and Ciliophora, even though they have different ecological functions and different dispersal modes. In comparison to the null models, both OTU and phylogenetic diversities showed spatial structures between forests, but only phylogenetic diversity showed spatial patterns within forests. These results suggest that the biogeographies of macro-and micro-organismal eukaryotes in lowland Neotropical rainforests are partially structured by the same general processes. As with arthropods, the protists high alpha diversity within forests presents problems for estimating their local diversity, and shows that regional diversity cannot be easily estimated because of low turnover between forests.

ecology↗