184 research outputs found

    Neckera, Forsstroemia and Alleniella (Neckeraceae, Bryophyta) redefined based on phylogenetic analyses

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    Phylogenetic relationships of species within the pleurocarpous moss genus Neckera s.l. (Neckeraceae) are reconstructed based on three genomic regions: the plastid rps4-trnT-trnL-trnF cluster and the rpl16 group II intron, as well as the internal transcribed spacer region of the nuclear ribosomal DNA (ITS1-5.8S-ITS2). The phylogenetic reconstruction suggests numerous taxonomic changes within the Neckeraceae. Two unispecific Asian genera are described as new: Taiwanobryopsis to accommodate Neckera warburgii, and Indoneckera to accommodate Neckera himalayana. Seven of the other "Neckera" species, all distributed in Asia, are transferred to Forsstroemia, and a further four Asian species to Taiwanobryum. Six Southern Hemisphere or tropical species (one from New Zealand, one from Africa, four from South America) are transferred to Alleniella. After these adjustments, Neckera becomes a northern hemisphere, mainly temperate, genus of c. 10 species that are absent from the tropics. It is in this context morphologically characterized by lack of paraphyllia (except N. californica) and an absent or weak costa. Alleniella has two species-the first diverging lineages-in the northern hemisphere, but the rest of the currently 15 species are distributed in the southern hemisphere and most of the species occur in mountain habitats in the tropics; it is however absent from tropical Asia and very scarce in Asia in general. Twelve of the 15 species have paraphyllia, which is the clearest morphological distinction from Neckera. Forsstroemia with 19 species, heavily concentrated in Asia, is the largest genus in the Neckeraceae. Clearly longer and more distinct costa distinguishes the genus from Neckera and Alleniella. Taiwanobryum is a morphologically heterogeneous Asian genus of nine species. Neckera decurrens Broth. is synonymized with Forsstroemia fauriei and Neckera valentiniana Besch. with Alleniella ehrenbergii.Peer reviewe

    Women's Struggle in Finding Truth - A comparative study of the South African TRC and Rwandan Gacacas

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    The role of women in post-conflict countries in Africa has always been less prioritised when working for reconciliation. Our aim in this thesis is to compare how the gacacas in Rwanda and TRC´s in South Africa treated the suffering of, and justice for women and what healing processes were put in place to help them. Truth Commissions are a form of reconciliation theory which will be further analysed in this thesis in order to investigate the participation and treatment of women in these two countries. When comparing them we have found that the truth commissions are in fact gender-biased. South African and Rwandan women were less prioritised than men in the treatment during truth commissions to find justice for their suffering

    Phylogenetic analyses reveal high levels of polyphyly among pleurocarpous lineages as well as novel clades

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    Phylogenetic analyses of the Hypnales usually show the same picture of poorly resolved trees with a large number of polyphyletic taxa and low support for the few reconstructed clades. One odd clade, however, consisting of three genera that are currently treated either within the Leskeaceae (Miyabea) or Neckeraceae (Homaliadelphus and Bissetia), was retrieved in a previously published phylogeny based on chloroplast rbcL. In order to elucidate the reliability of the observed Homaliadelphus - Miyabea - Bissetia - clade (HMB-clade) and to reveal its phylogenetic relationships a molecular study based on a representative set of hypnalean taxa was performed. Sequence data from all three genomes, namely the ITS1 and 2 (nuclear), the trnS-rps4-trnT-trnL-trnF cluster (plastid), the nad5 intron (mitochondrial), were analyzed. Although the phylogenetic reconstruction of the combined data set was not fully resolved regarding the backbone it clearly indicated the polyphyletic nature of various hypnalean families, such as the Leskeaceae, Hypnaceae, Hylocomiaceae, Neckeraceae, Leptodontaceae and Anomodontaceae with respect to the included taxa. In addition the results favor the inclusion of the Leptodontaceae and Thamnobryaceae in the Neckeraceae. The maximally supported HMB-clade consisting of the three genera Homaliadelphus (2-3 species), Miyabea (3 species) and Bissetia (1 species) is resolved sister to a so far unnamed clade comprising Taxiphyllum aomoriense, Glossadelphus ogatae and Leptopterigynandrum. The well-resolved and supported HMB-clade, here formally described as the Miyabeaceae, fam. nov. is additionally supported by morphological characters such as strongly incrassate, porose leaf cells, a relatively weak and diffuse costa and the presence of dwarf males. The latter are absent in the Neckeraceae and the Leskeaceae. It is essentially an East Asian family, with one species occurring in North America.Phylogenetic analyses of the Hypnales usually show the same picture of poorly resolved trees with a large number of polyphyletic taxa and low support for the few reconstructed clades. One odd clade, however, consisting of three genera that are currently treated either within the Leskeaceae (Miyabea) or Neckeraceae (Homaliadelphus and Bissetia), was retrieved in a previously published phylogeny based on chloroplast rbcL. In order to elucidate the reliability of the observed Homaliadelphus - Miyabea - Bissetia - clade (HMB-clade) and to reveal its phylogenetic relationships a molecular study based on a representative set of hypnalean taxa was performed. Sequence data from all three genomes, namely the ITS1 and 2 (nuclear), the trnS-rps4-trnT-trnL-trnF cluster (plastid), the nad5 intron (mitochondrial), were analyzed. Although the phylogenetic reconstruction of the combined data set was not fully resolved regarding the backbone it clearly indicated the polyphyletic nature of various hypnalean families, such as the Leskeaceae, Hypnaceae, Hylocomiaceae, Neckeraceae, Leptodontaceae and Anomodontaceae with respect to the included taxa. In addition the results favor the inclusion of the Leptodontaceae and Thamnobryaceae in the Neckeraceae. The maximally supported HMB-clade consisting of the three genera Homaliadelphus (2-3 species), Miyabea (3 species) and Bissetia (1 species) is resolved sister to a so far unnamed clade comprising Taxiphyllum aomoriense, Glossadelphus ogatae and Leptopterigynandrum. The well-resolved and supported HMB-clade, here formally described as the Miyabeaceae, fam. nov. is additionally supported by morphological characters such as strongly incrassate, porose leaf cells, a relatively weak and diffuse costa and the presence of dwarf males. The latter are absent in the Neckeraceae and the Leskeaceae. It is essentially an East Asian family, with one species occurring in North America.Phylogenetic analyses of the Hypnales usually show the same picture of poorly resolved trees with a large number of polyphyletic taxa and low support for the few reconstructed clades. One odd clade, however, consisting of three genera that are currently treated either within the Leskeaceae (Miyabea) or Neckeraceae (Homaliadelphus and Bissetia), was retrieved in a previously published phylogeny based on chloroplast rbcL. In order to elucidate the reliability of the observed Homaliadelphus - Miyabea - Bissetia - clade (HMB-clade) and to reveal its phylogenetic relationships a molecular study based on a representative set of hypnalean taxa was performed. Sequence data from all three genomes, namely the ITS1 and 2 (nuclear), the trnS-rps4-trnT-trnL-trnF cluster (plastid), the nad5 intron (mitochondrial), were analyzed. Although the phylogenetic reconstruction of the combined data set was not fully resolved regarding the backbone it clearly indicated the polyphyletic nature of various hypnalean families, such as the Leskeaceae, Hypnaceae, Hylocomiaceae, Neckeraceae, Leptodontaceae and Anomodontaceae with respect to the included taxa. In addition the results favor the inclusion of the Leptodontaceae and Thamnobryaceae in the Neckeraceae. The maximally supported HMB-clade consisting of the three genera Homaliadelphus (2-3 species), Miyabea (3 species) and Bissetia (1 species) is resolved sister to a so far unnamed clade comprising Taxiphyllum aomoriense, Glossadelphus ogatae and Leptopterigynandrum. The well-resolved and supported HMB-clade, here formally described as the Miyabeaceae, fam. nov. is additionally supported by morphological characters such as strongly incrassate, porose leaf cells, a relatively weak and diffuse costa and the presence of dwarf males. The latter are absent in the Neckeraceae and the Leskeaceae. It is essentially an East Asian family, with one species occurring in North America.Peer reviewe

    Phylogeny-Based Comparative Methods Question the Adaptive Nature of Sporophytic Specializations in Mosses

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    Adaptive evolution has often been proposed to explain correlations between habitats and certain phenotypes. In mosses, a high frequency of species with specialized sporophytic traits in exposed or epiphytic habitats was, already 100 years ago, suggested as due to adaptation. We tested this hypothesis by contrasting phylogenetic and morphological data from two moss families, Neckeraceae and Lembophyllaceae, both of which show parallel shifts to a specialized morphology and to exposed epiphytic or epilithic habitats. Phylogeny-based tests for correlated evolution revealed that evolution of four sporophytic traits is correlated with a habitat shift. For three of them, evolutionary rates of dual character-state changes suggest that habitat shifts appear prior to changes in morphology. This suggests that they could have evolved as adaptations to new habitats. Regarding the fourth correlated trait the specialized morphology had already evolved before the habitat shift. In addition, several other specialized “epiphytic” traits show no correlation with a habitat shift. Besides adaptive diversification, other processes thus also affect the match between phenotype and environment. Several potential factors such as complex genetic and developmental pathways yielding the same phenotypes, differences in strength of selection, or constraints in phenotypic evolution may lead to an inability of phylogeny-based comparative methods to detect potential adaptations.Peer reviewe

    A century later – Pinnatella gollanii is still alive!

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    Pinnatella gollanii Broth., previously known only from north Indian collections dating back to 1903, was rediscovered in Nepal in 2001.Peer reviewe

    Phylogeny of Neckeropsis and Himantocladium (Neckeraceae, Bryophytina)

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    Two closely related tropical genera from the pleurocarpous moss family Neckeraceae are revised: the second largest genus in the family, Neckeropsis, currently with 29 species, and Himantocladium, comprising six species. Twenty-one species of Neckeropsis and five of Himantocladium were included in this study, which is based on phylogenetic analyses using sequence level data from the plastid (rps4)-trnT-trnL-trnF cluster and rpl16 as well as nuclear ITS1 & 2. Neckeropsis appeared as polyphyletic. Neckeropsis s. str. comprises 12 species and a further four species, not included in the analysis, are tentatively retained in the genus based on morphology. Four new genera are segregated from Neckeropsis: Pengchengwua (with one sp.), Planicladium (two spp.), Pseudoparaphysanthus (five spp.), and Neckeromnion (five spp.). Neckeropsis gracilis is synonymized with Neckeromnion urocladum and reported for the first time from Laos. Four molecular analyzed species are resolved in the Himantocladium s. str. clade, with a fifth species being added solely on morphological basis. Himantocladium formosicum is transferred to Neckeropsis. Leaf-like paraphyses (ramenta), unique in Neckeropsis s. str., have evolved two times. In addition, the rare Noguchiodendron sphaerocarpum from the Himalayan region, the single species in its genus, was included in a phylogenetic analysis for the first time and it was found to be closely related to the Asian genus Taiwanobryum.Peer reviewe

    Evolution of the tRNALeu (UAA) intron and congruence of genetic markers in lichen-symbiotic Nostoc

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    The group I intron interrupting the tRNALeu UAA gene (trnL) is present in most cyanobacterial genomes as well as in the plastids of many eukaryotic algae and all green plants. In lichen symbiotic Nostoc, the P6b stem-loop of trnL intron always involves one of two different repeat motifs, either Class I or Class II, both with unresolved evolutionary histories. Here we attempt to resolve the complex evolution of the two different trnL P6b region types. Our analysis indicates that the Class II repeat motif most likely appeared first and that independent and unidirectional shifts to the Class I motif have since taken place repeatedly. In addition, we compare our results with those obtained with other genetic markers and find strong evidence of recombination in the 16S rRNA gene, a marker widely used in phylogenetic studies on Bacteria. The congruence of the different genetic markers is successfully evaluated with the recently published software Saguaro, which has not previously been utilized in comparable studies.Peer reviewe

    Heterologous Expression of the Phytochelatin Synthase CaPCS2 from Chlamydomonas acidophila and Its Effect on Different Stress Factors in Escherichia coli

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    Phytochelatins (PCs) are cysteine-rich small peptides, enzymatically synthesized from reduced glutathione (GSH) by cytosolic enzyme phytochelatin synthase (PCS). The open reading frame (ORF) of the phytochelatin synthase CaPCS2 gene from the microalgae Chlamydomonas acidophila was heterologously expressed in Escherichia coli strain DH5 alpha, to analyze its role in protection against various abiotic agents that cause cellular stress. The transformed E. coli strain showed increased tolerance to exposure to different heavy metals (HMs) and arsenic (As), as well as to acidic pH and exposure to UVB, salt, or perchlorate. In addition to metal detoxification activity, new functions have also been reported for PCS and PCs. According to the results obtained in this work, the heterologous expression of CaPCS2 in E. coli provides protection against oxidative stress produced by metals and exposure to different ROS-inducing agents. However, the function of this PCS is not related to HM bioaccumulation
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