113 research outputs found
Consequence of habitat specificity: a rising risk of habitat loss for endemic and sub-endemic woody species under climate change in the Hyrcanian ecoregion
Endemic species are more impacted by climate change than other taxa. However, assessing the vulnerability of endemics to these changes in some regions, such as the Hyrcanian forest, is limited, despite its importance for biodiversity and ecosystem function. To address the question of expected habitat shifts under climate change across the Hyrcanian ecoregion, we built an ensemble of species distribution models (SDM) under two emission scenarios (RCP 4.5 and RCP 8.5) for 15 endemic woody taxa. To identify the potential priority conservation areas, we also applied a spatial prioritization approach. Overall, our results suggest that the impacts of climate change are more severe on the eastern parts of the region (Golestan) and the Talysh Mountains (north-western Hyrcanian ecoregion) with over 85% and 34% loss of suitable habitats over the next 80 years. The central part of the Alborz Mountains (Mazandaran) and some areas in the Talysh Mountains could be potential climatic refugia under the future conditions for endemic taxa. The most prominent changes are expected for Ruscus hyrcanus, Gleditsia capsica, Acer velutinum, Frangula grandifolia, and Buxus hyrcana. The worrying predicted loss of suitable habitats for most studied taxa would dramatically affect the stability and resilience of forests, threatening thus biodiversity of the Hyrcanian ecoregion. We present the first estimation of the potential risks involved and provide useful support for regional climate-adaptation strategy, indicating potential conservation priority areas for maintaining and preserving its resources. Notably, only 13.4% of areas designated for conservation and management under climate change will be located within the current Hyrcanian protected areas, yet the majority of these areas are classified as low priority
Room-Temperature Distance Measurements of Immobilized Spin-Labeled Protein by DEER/PELDOR
Nitroxide spin labels are used for double electron-electron
resonance (DEER) measurements of distances between sites in
biomolecules. Rotation of gem-dimethyls in commonly used
nitroxides causes spin echo dephasing times (Tm) to be too
short to perform DEER measurements at temperatures between
∼80 and 295 K, even in immobilized samples. A spirocyclohexyl
spin label has been prepared that has longer Tm between 80
and 295 K in immobilized samples than conventional labels. Two
of the spirocyclohexyl labels were attached to sites on T4 lysozyme introduced by site-directed spin labeling. Interspin
distances up to ∼4 nm were measured by DEER at
temperatures up to 160 K in water/glycerol glasses. In a glassy
trehalose matrix the Tm for the doubly labeled T4 lysozyme was
long enough to measure an interspin distance of 3.2 nm at 295
K, which could not be measured for the same protein labeled
with the conventional 1-oxyl-2,2,5,5-tetramethyl-3-pyrroline-3-
(methyl)methanethio-sulfonate label
Room-Temperature Distance Measurements of Immobilized Spin-Labeled Protein by DEER/PELDOR
Nitroxide spin labels are used for double electron-electron
resonance (DEER) measurements of distances between sites in
biomolecules. Rotation of gem-dimethyls in commonly used
nitroxides causes spin echo dephasing times (Tm) to be too
short to perform DEER measurements at temperatures between
∼80 and 295 K, even in immobilized samples. A spirocyclohexyl
spin label has been prepared that has longer Tm between 80
and 295 K in immobilized samples than conventional labels. Two
of the spirocyclohexyl labels were attached to sites on T4 lysozyme introduced by site-directed spin labeling. Interspin
distances up to ∼4 nm were measured by DEER at
temperatures up to 160 K in water/glycerol glasses. In a glassy
trehalose matrix the Tm for the doubly labeled T4 lysozyme was
long enough to measure an interspin distance of 3.2 nm at 295
K, which could not be measured for the same protein labeled
with the conventional 1-oxyl-2,2,5,5-tetramethyl-3-pyrroline-3-
(methyl)methanethio-sulfonate label
Rapid-Scan EPR of Immobilized Nitroxides
X-band electron paramagnetic resonance spectra of immobilized nitroxides were obtained by rapid scan at 293 K. Scan widths were 155 G with 13.4 kHz scan frequency for 14N-perdeuterated tempone and for T4 lysozyme doubly spin labeled with an iodoacetamide spirocyclohexyl nitroxide and 100 G with 20.9 kHz scan frequency for 15N-perdeuterated tempone. These wide scans were made possible by modifications to our rapid-scan driver, scan coils made of Litz wire, and the placement of highly conducting aluminum plates on the poles of a Bruker 10 magnet to reduce resistive losses in the magnet pole faces. For the same data acquisition time, the signal-to-noise for the rapid-scan absorption spectra was about an order of magnitude higher than for continuous wave first-derivative spectra recorded with modulation amplitudes that do not broaden the lineshapes
Rapid-Scan EPR of Immobilized Nitroxides
X-band electron paramagnetic resonance spectra of immobilized nitroxides were obtained by rapid scan at 293 K. Scan widths were 155 G with 13.4 kHz scan frequency for 14N-perdeuterated tempone and for T4 lysozyme doubly spin labeled with an iodoacetamide spirocyclohexyl nitroxide and 100 G with 20.9 kHz scan frequency for 15N-perdeuterated tempone. These wide scans were made possible by modifications to our rapid-scan driver, scan coils made of Litz wire, and the placement of highly conducting aluminum plates on the poles of a Bruker 10 magnet to reduce resistive losses in the magnet pole faces. For the same data acquisition time, the signal-to-noise for the rapid-scan absorption spectra was about an order of magnitude higher than for continuous wave first-derivative spectra recorded with modulation amplitudes that do not broaden the lineshapes
Splitting or lumping? A conservation dilemma exemplified by the critically endangered Dama Gazelle (Nanger dama)
Managers of threatened species often face the dilemma of whether to keep populations separate to conserve local adaptations and minimize the risk of outbreeding, or whether to manage populations jointly to reduce loss of genetic diversity and minimise inbreeding. In this study we examine genetic relatedness and diversity in three of the five last remaining wild populations of dama gazelle and a number of captive populations, using mtDNA control region and cytochrome b data. Despite the sampled populations belonging to the three putative subspecies, which are delineated according to phenotypes and geographical location, we find limited evidence for phylogeographical structure within the data and no genetic support for the putative subspecies. In the light of these data we discuss the relevance of inbreeding depression, outbreeding depression, adaptive variation, genetic drift, and phenotypic variation to the conservation of the dama gazelle and make some recommendations for its future conservation management. The genetic data suggest that the best conservation approach is to view the dama gazelle as a single species without subspecific divisions
Morphological differentiation supports the genetic pattern of the geographic structure of Juniperus thurifera (Cupressaceae)
Relationships among Cedrus libani, C. brevifolia and C. atlantica as revealed by the morphological and anatomical needle characters
The section Atlanticae of the genus <i>Luzula</i> (Juncaceae)
The section <i>Atlanticae</i> of the genus <i>Luzula</i> (Juncaceae).- <i> Luzula atlantica</i> Braun-Blanq. and <i>Luzula tibestica (Quézel) Zarhan ex Romo & Boratyński are the only representatives of the section <i> Atlanticae Kirschner of the genus <i>Luzula</i>. <i>Luzula atlantica</i> is an endemic plant from the High Atlas Mountains and <i>Luzula tibestica</i> is endemic to the Tibesti massif. Both taxa are studied from a nomenclatural, morphological, chorological and biogeographical point of view. These taxa, owing to their low dispersion capacity, have probably diversified in situ.<br><br>La sección Atlanticae del género <i>Luzula</i> (Juncaceae).- <i>Luzula atlantica</i> Braun-Blanq. y <i>Luzula tibestica (Quézel) Zarhan ex Romo & Boratynski son los únicos representantes de la sección Atlanticae Kirschner del género <i>Luzula</i>. <i>Luzula atlantica</i> es un endemismo del Alto Atlas y <i>Luzula tibestica</i> es una planta endémica del macizo de Tibesti. Ambos taxones son estudiados desde el punto de vista morfológico, nomenclatural, corológico y biogeográfico. Estos taxones, por su baja tasa de dispersión, se han diversificado probablemente in situ
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