Publications by authors named "Sebastian Dirren"

Historical specimens from museum collections provide a valuable source of material also from remote areas or regions of conflict that are not easily accessible to scientists today. With this study, we are providing a taxon-complete phylogeny of snowfinches using historical DNA from whole skins of an endemic species from Afghanistan, the Afghan snowfinch, Pyrgilauda theresae. To resolve the strong conflict between previous phylogenetic hypotheses, we generated novel mitogenome sequences for selected taxa and genome-wide SNP data using ddRAD sequencing for all extant snowfinch species endemic to the Qinghai-Tibet Plateau (QTP) and for an extended intraspecific sampling of the sole Central and Western Palearctic snowfinch species (Montifringilla nivalis).

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During the last decades, the planktonic cyanobacterium Planktothrix rubescens became a dominant primary producer in many deep pre-alpine lakes. While altered physiochemical conditions due to lake warming seem to favour this cyanobacterial species, its dominance is partly attributed to factors conferring grazing resistance. The rigid structure of the cyanobacterial filaments and toxic secondary metabolites (e.

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The genus Tetrahymena (Ciliophora, Oligohymenophorea) probably represents the best studied ciliate genus. At present, more than forty species have been described. All are colorless, i.

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We isolated 17 strains of the amoeboid genus Nuclearia (Opisthokonta) from five Swiss lakes. Eight of these nucleariid isolates were associated with bacterial endosymbionts and/or ectosymbionts. Amoebae were characterized morphologically and by their 18S rRNA genes.

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We present a fascinating triad relationship between a eukaryotic amoeba and its two bacterial symbionts. The morphological characteristics of the amoeba allowed for a confident assignment to the genus Nuclearia (Opisthokonta, Nucleariidae), but species identification resulted in an ambiguous result. Sequence analysis indicated an affiliation to the species N.

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