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  • 1
    Language: English
    In: Proceedings of the National Academy of Sciences of the United States of America, 12 June 2018, Vol.115(24), pp.6309-6314
    Description: Sec1/Munc18 (SM) proteins contribute to membrane fusion by interacting with Qa-SNAREs or nascent -SNARE complexes. Gymnosperms and the basal angiosperm have only a single gene related to the gene in However, the genomes of most angiosperms including encode three SEC1-related SM proteins of which only KEULE has been functionally characterized as interacting with the cytokinesis-specific Qa-SNARE KNOLLE during cell-plate formation. Here we analyze the closest paralog of KEULE named SEC1B. In contrast to the cytokinesis defects of mutants, mutants are homozygous viable. However, the double mutant was nearly gametophytically lethal, displaying collapsed pollen grains, which suggests substantial overlap between SEC1B and KEULE functions in secretion-dependent growth. SEC1B had a strong preference for interaction with the evolutionarily ancient Qa-SNARE SYP132 involved in secretion and cytokinesis, whereas KEULE interacted with both KNOLLE and SYP132. This differential interaction with...
    Subject(s): Qa-Snares ; Sec1/Munc18 ; Cell-Plate Formation ; Membrane Traffic ; Secretion ; Arabidopsis -- Metabolism ; Arabidopsis Proteins -- Metabolism ; Cytokinesis -- Physiology ; Membrane Fusion -- Physiology ; Protein Transport -- Physiology
    ISSN: 0027-8424
    E-ISSN: 1091-6490
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  • 2
    In: Nature, 2013, Vol.497(7451), p.611
    Description: Apes and Old World monkeys are prominent components of modern African and Asian ecosystems, yet the earliest phases of their evolutionary history have remained largely undocumented. The absence of crown catarrhine fossils older than ∼20 million years (Myr) has stood in stark contrast to molecular divergence estimates of ∼25-30 Myr for the split between Cercopithecoidea (Old World monkeys) and Hominoidea (apes), implying long ghost lineages for both clades. Here we describe the oldest known fossil 'ape', represented by a partial mandible preserving dental features that place it with 'nyanzapithecine' stem hominoids. Additionally, we report the oldest stem member of the Old World monkey clade, represented by a lower third molar. Both specimens were recovered from a precisely dated 25.2-Myr-old stratum in the Rukwa Rift, a segment of the western branch of the East African Rift in Tanzania. These finds extend the fossil record of apes and Old World monkeys well into the Oligocene epoch of Africa, suggesting a possible link between diversification of crown catarrhines and changes in the African landscape brought about by previously unrecognized tectonic activity in the East African rift system.
    Subject(s): Sciences (General) ; Physics;
    ISSN: 0028-0836
    E-ISSN: 14764687
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  • 3
    Article
    Article
    2013
    ISSN: 00121207  ISSN: 18660452 
    In: Deutsches Arzteblatt International, 8 February 2013, Vol.110(6), pp.218-220
    ISSN: 00121207
    ISSN: 18660452
    E-ISSN: 01722107
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  • 4
    Language: English
    In: The Journal of experimental biology, 15 April 2013, Vol.216(Pt 8), pp.1448-57
    Description: Arboreal substrates differ not only in diameter, but also in continuity and orientation. To gain more insight into the dynamics of small-branch locomotion in tetrapods we studied the veiled chameleon walking on inclined and declined perches of up to 60 deg slope. We found that forelimbs and hindlimbs contribute equally to the body's progression along inclines and declines. The higher-positioned limb's vertical impulses decreased with slope. And although vertical impulses in the lower-positioned limb increased with substrate slope, peak vertical forces decreased. The decrease in peak vertical forces in the lower-positioned limb can be explained by a considerable increase of tensile forces in the higher-positioned limb as the slope increases. In addition, limbs were more crouched on slopes whereas no changes in forward and backward reach were observed. Mediolateral impulses were the smallest amongst the force components, and lateral impulses (medially directed limb forces) exceeded medial...
    Subject(s): Walking ; Forelimb -- Physiology ; Hindlimb -- Physiology ; Lizards -- Physiology
    ISSN: 0022-0949
    E-ISSN: 1477-9145
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  • 5
    Language: English
    In: PloS one, 2011, Vol.6(2), p.e16793
    Description: Inconspicuous basidiomycetes from the order Sebacinales are known to be involved in a puzzling variety of mutualistic plant-fungal symbioses (mycorrhizae), which presumably involve transport of mineral nutrients. Recently a few members of this fungal order not fitting this definition and commonly referred to as ‘endophytes’ have raised considerable interest by their ability to enhance plant growth and to increase resistance of their host plants against abiotic stress factors and fungal pathogens. Using DNA-based detection and electron microscopy, we show that Sebacinales are not only extremely versatile in their mycorrhizal associations, but are also almost universally present as symptomless endophytes. They occurred in field specimens of bryophytes, pteridophytes and all families of herbaceous angiosperms we investigated, including liverworts, wheat, maize, and the non-mycorrhizal model plant Arabidopsis thaliana. They were present in all habitats we studied on four continents....
    Subject(s): Life Sciences ; Cellular Biology ; Sebacinales ; Endophyte ; Relation Hote-Parasite ; Relation Plante-Microorganisme ; Sciences (General)
    ISSN: 1932-6203
    E-ISSN: 1932-6203
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  • 6
    In: Global Change Biology, November 2016, Vol.22(11), pp.3804-3813
    Description: The interaction between xylem phenology and climate assesses forest growth and productivity and carbon storage across biomes under changing environmental conditions. We tested the hypothesis that patterns of wood formation are maintained unaltered despite the temperature changes across cold ecosystems. Wood microcores were collected weekly or biweekly throughout the growing season for periods varying between 1 and 13 years during 1998–2014 and cut in transverse sections for assessing the onset and ending of the phases of xylem differentiation. The data set represented 1321 trees belonging to 10 conifer species from 39 sites in the Northern Hemisphere and covering an interval of mean annual temperature exceeding 14 K. The phenological events and mean annual temperature of the sites were related linearly, with spring and autumnal events being separated by constant intervals across the range of temperature analysed. At increasing temperature, first enlarging, wall‐thickening and mature tracheids appeared earlier, and last enlarging and wall‐thickening tracheids occurred later. Overall, the period of wood formation lengthened linearly with the mean annual temperature, from 83.7 days at −2 °C to 178.1 days at 12 °C, at a rate of 6.5 days °C. April–May temperatures produced the best models predicting the dates of wood formation. Our findings demonstrated the uniformity of the process of wood formation and the importance of the environmental conditions occurring at the time of growth resumption. Under warming scenarios, the period of wood formation might lengthen synchronously in the cold biomes of the Northern Hemisphere.
    Subject(s): Cambium ; Cell Differentiation ; Cell Production ; Climate Change ; Conifers ; Growth ; Meristem ; Secondary Wall Formation
    ISSN: 1354-1013
    E-ISSN: 1365-2486
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  • 7
    Language: English
    In: Annals of Forest Science, 2011, Vol.68(6), pp.1115-1125
    Description: Commercial thinning (CT) could contribute to increase short-term tree growth and be beneficial in a cold climate, as in boreal regions. Thus, growth rate, ring density and flexural modulus of elasticity (MOE) of trees may change after CT. Moreover, mechanical wood properties vary with position in the tree, and there is a need to develop optimal log allocation strategies in order to allocate logs to their best use.The objectives of the study were to evaluate the impact of commercial thinning on the lumber quality of nine thinned stands compared with unthinned stands and to determine whether this impact varies longitudinally along the first 4 m of the stem.Despite a significant increase in ring width following thinning (p = 0.0003), annual variations in ring density were subtle. No significant variation in average ring density due to CT was observed (p = 0.5122) after thinning, which may be explained by between-stand variability. Thinning showed no significant effect on flexural MOE over a 10-year period. Moreover, variability in average ring density along the stem with tree height was greater than that induced by thinning. A significant decrease in ring density was observed up the stem (from 490 to 463 kg m−3 up to the fourth metre, p 〈 0.0001).Because it induced increased growth without negative effects on wood mechanical properties, thinning is advisable for slow growth naturally regenerated black spruce stands in the northern boreal region.
    Subject(s): Black spruce ; Modulus of elasticity ; Ring density ; Wood quality ; Commercial thinning
    ISSN: 1286-4560
    E-ISSN: 1297-966X
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  • 8
    Language: English
    In: Tree physiology, 01 November 2017, Vol.37(11), pp.1554-1563
    Description: The reduction of competition through thinning increases radial growth in the stem and roots of many conifer species. However, not much is known about the effect of thinning on the dynamics of wood formation and intra-annual development of the growth ring, especially in the roots, which are an essential part of the tree for stability and resource acquisition. The aim of this study was to evaluate the effect of an experimental thinning on the dynamics and phenology of xylogenesis in the stem and roots of black spruce and balsam fir. Experimental and control trees were selected in two mature even-aged stands, one black spruce (Picea mariana (Mill.) BSP) and one balsam fir (Abies balsamea (L.) Mill.). Wood microcores were collected weekly in the stem and roots from May to October for a period of 4 years. The onset and ending of each cell differentiation phase were computed, as well as growth rate and total cell production. Results show that thinning increased the cell production rate of stem...
    Subject(s): Abies Balsamea ; Picea Mariana ; Boreal Forest ; Cell Differentiation ; Growth ; Intra-Annual Ring Development ; Phenology ; Abies -- Growth & Development ; Picea -- Growth & Development ; Xylem -- Growth & Development
    ISSN: 0829-318X
    E-ISSN: 1758-4469
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  • 9
    Language: English
    In: Annals of Forest Science, 2015, Vol.72(1), pp.77-87
    Description: • CONTEXT : The Canadian forest industry is turning its attention towards the unmanaged areas at higher latitudes, where the forest resource is still poorly understood because of lack of accessibility. Despite a lower productivity in terms of volume, northern stands are expected to produce wood of higher quality, which may make these areas attractive for management and production. • AIMS : This study aims to test the hypothesis that trees at high latitudes produce wood with better basic properties than trees at lower latitudes. • METHODS : Growth and wood characteristics were assessed according to cambial age in 25 black spruce (Picea mariana) trees from five sites located along an alti-latitudinal gradient in Quebec. • RESULTS : Sites at higher latitudes and altitudes exhibited slower growth rates and lower stem volume. Wood density and mechanical properties were higher in the sites located at lower latitudes or altitudes. Fiber size had higher values in southern sites, but only at younger ages. Principal component analysis confirmed these results, with the northernmost site being the one where growth, density and mechanical properties were generally lowest. • CONCLUSION : The reduction in growth was not compensated by increases in the basic properties of wood. More extensive samplings are needed to validate the results at larger scale. ; p. 77-87.
    Subject(s): Boreal forest ; Cambial age ; Fibre length ; Modulus of elasticity ; Modulus of rupture ; Wood density
    ISSN: 1286-4560
    E-ISSN: 1297-966X
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  • 10
    Language: English
    In: Alpine Botany, 4/2017, Vol.127(1), pp.85-95
    Description: Extinction of biodiversity due to human activities is a severe global problem. In Europe, however, only a few plant species died out so far. We investigated a dubious, disregarded taxon—Saxifraga oppositifolia subsp. amphibia—which became extinct in the 1960s. It exclusively occurred in a specific niche, namely in seasonally flooded waterside bank vegetation around Lake Constance in Germany and Switzerland. It has either been interpreted as a glacial relict or as a recent dealpine taxon. Using herbarium material, we conducted phylogenetic analyses based on ITS and cpDNA sequence variation. The taxon shared a chloroplast haplotype of S. oppositifolia, which is mainly distributed in the Alps, favouring the dealpine hypothesis. Nuclear data revealed several paralogous copies nested inside S. oppositifolia, most of which, however, differed from other S. oppositifolia accessions including those from the vicinity of Lake Constance. The oldest mean stem node ages of these ITS copies date between 0.91 and 0.28 my. Contradicting cpDNA, this may indicate that this saxifrage was a distinct taxon and possibly a relict originating in Middle Pleistocene glaciations. If so, the present study exemplifies that arctic-alpine plants survived in specific niches at low altitudes during interglacials and that corresponding taxa with a limited distribution are especially prone to extinction.
    Subject(s): Life Sciences ; Plant Sciences ; Plant Ecology ; Ecology ; Life Sciences, General ; Forestry ; Arctic-Alpine Plants ; Extinction ; Its ; Neotypification ; Plastid Sequences ; Quaternary Glaciation ; Saxifragaceae ; Forestry ; Botany ; Ecology;
    ISSN: 1664-2201
    E-ISSN: 1664-221X
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