Sort by: Order: Results:

Now showing items 1-4 of 4
  • Puente-Sánchez, Fernando; Díaz, Silvia; Penacho, Vanessa; Aguilera, Angeles; Olsson, Sanna (2018)
    To better understand heavy metal tolerance in Chlamydomonas acidophila, an extremophilic green alga, we assembled its transcriptome and measured transcriptomic expression before and after Cd exposure in this and the neutrophilic model microalga Chlamydomonas reinhardtii. Genes possibly related to heavy metal tolerance and detoxification were identified and analyzed as potential key innovations that enable this species to live in an extremely acid habitat with high levels of heavy metals. In addition we provide a data set of single orthologous genes from eight green algal species as a valuable resource for comparative studies including eukaryotic extremophiles. Our results based on differential gene expression, detection of unique genes and analyses of codon usage all indicate that there are important genetic differences in C. acidophila compared to C. reinhardtii. Several efflux family proteins were identified as candidate key genes for adaptation to acid environments. This study suggests for the first time that exposure to cadmium strongly increases transposon expression in green algae, and that oil biosynthesis genes are induced in Chlamydomonas under heavy metal stress. Finally, the comparison of the transcriptomes of several acidophilic and non-acidophilic algae showed that the Chlamydomonas genus is polyphyletic and that acidophilic algae have distinctive aminoacid usage patterns.
  • Schneider, Julia; Hoffmann, Bernd; Fevola, Cristina; Schmidt, Marie Luisa; Imholt, Christian; Fischer, Stefan; Ecke, Frauke; Hoernfeldt, Birger; Magnusson, Magnus; Olsson, Gert E.; Rizzoli, Annapaola; Tagliapietra, Valentina; Chiari, Mario; Reusken, Chantal; Buzan, Elena; Kazimirova, Maria; Stanko, Michal; White, Thomas A.; Reil, Daniela; Obiegala, Anna; Meredith, Anna; Drexler, Jan Felix; Essbauer, Sandra; Henttonen, Heikki; Jacob, Jens; Hauffe, Heidi C.; Beer, Martin; Heckel, Gerald; Ulrich, Rainer G. (2021)
    The development of new diagnostic methods resulted in the discovery of novel hepaciviruses in wild populations of the bank vole (Myodes glareolus, syn. Clethrionomys glareolus). The naturally infected voles demonstrate signs of hepatitis similar to those induced by hepatitis C virus (HCV) in humans. The aim of the present research was to investigate the geographical distribution of bank vole-associated hepaciviruses (BvHVs) and their genetic diversity in Europe. Real-time reverse transcription polymerase chain reaction (RT-qPCR) screening revealed BvHV RNA in 442 out of 1838 (24.0%) bank voles from nine European countries and in one of seven northern red-backed voles (Myodes rutilus, syn. Clethrionomys rutilus). BvHV RNA was not found in any other small mammal species (n = 23) tested here. Phylogenetic and isolation-by-distance analyses confirmed the occurrence of both BvHV species (Hepacivirus F and Hepacivirus J) and their sympatric occurrence at several trapping sites in two countries. The broad geographical distribution of BvHVs across Europe was associated with their presence in bank voles of different evolutionary lineages. The extensive geographical distribution and high levels of genetic diversity of BvHVs, as well as the high population fluctuations of bank voles and occasional commensalism in some parts of Europe warrant future studies on the zoonotic potential of BvHVs.
  • Wayland, Matthew T.; Vainio, Jouni K.; Gibson, David I.; Herniou, Elisabeth A.; Littlewood, D. Timothy J.; Väinölä, Risto (2015)
    The acanthocephalan genus Echinorhynchus Zoega in Müller, 1776 (sensu Yamaguti 1963) is a large and widespread group of parasites of teleost fish and malacostracan crustaceans, distributed from the Arctic to the Antarctic in habitats ranging from freshwaters to the deep-sea. A total of 52 species are currently recognised based on the conventional morphological species concept; however, the true diversity in the genus is masked by cryptic speciation. The considerable diversity within Echinorhynchus is an argument for subdividing the genus if monophyletic groups with supporting morphological characters can be identified. With this objective in mind, partial sequences of two genes with different rates of evolution and patterns of inheritance (nuclear 28S rRNA and mitochondrial cytochrome c oxidase subunit I) were used to infer the phylogenetic relationships among eight taxa of Echinorhynchus. These included representatives of each of three genus group taxa proposed in a controversial revision of the genus based on cement gland pattern, namely Echinorhynchus (sensu stricto), Metechinorhynchus Petrochenko, 1956 and Pseudoechinorhynchus Petrochenko, 1956. These groupings have previously been rejected by some authorities, because the diagnostic character is poorly defined; this study shows that Echinorhynchus (sensu stricto) and Metechinorhynchus are not natural, monophyletic groups. A revision of Echinorhynchus will require tandem molecular phylogenetic and morphological analyses of a larger sample of taxa, but this study has identified two morhological characters that might potentially be used to define new genera. The estimated phylogeny also provides insight into the zoogeographical history of Echinorhynchus spp. We postulate that the ancestral Echinorhynchus had a freshwater origin and the genus subsequently invaded the sea, probably several times. The freshwater taxa of the E. bothniensis Zdzitowiecki & Valtonen, 1987 clade may represent a reinvasion of freshwater by one or more ancestral marine species.
  • Kistenich, Sonja; Rikkinen, Jouko K.; Thüs, Holger; Vairappan, Charles S.; Wolseley, Patricia A.; Timdal, Einar (2018)
    Krogia borneensis Kistenich & Timdal, K. isidiata Kistenich & Timdal and K. macrophylla Kistenich & Timdal are described as new species, the first from Borneo and the two latter from New Caledonia. The new species are supported by morphology, secondary chemistry and DNA sequence data. Krogia borneensis and K. isidiata contain sekikaic and homosekikaic acid, both compounds reported here for the first time from the genus. Krogia macrophylla contains an unknown compound apparently related to boninic acid as the major compound. DNA sequences (mtSSU and nrITS) are provided for the first time for Krogia and a phylogeny of the genus based on 15 accessions of five of the six accepted species is presented. Krogia antillarum is reported as new to Brazil, Guatemala and Mexico.