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We report the first simultaneous measurements of ?15N and ?13C of DNA extracted from surface soils. The isotopic composition of DNA differed significantly among nine different soils. The ?13C and ?15N of DNA was correlated with ?13C and ?15N of soil, respectively, suggesting that the isotopic composition of DNA is strongly influenced by the isotopic composition of soil organic matter. However, in all samples DNA was enriched in 13C relative to soil, indicating microorganisms fractionated C during assimilation or preferentially used 13C enriched substrates. Enrichment of DNA in 15N relative to soil was not consistently observed, but there were significant differences between ?15N of DNA and ?15N of soil for three...
We report the first simultaneous measurements of ?15N and ?13C of DNA extracted from surface soils. The isotopic composition of DNA differed significantly among nine different soils. The ?13C and ?15N of DNA was correlated with ?13C and ?15N of soil, respectively, suggesting that the isotopic composition of DNA is strongly influenced by the isotopic composition of soil organic matter. However, in all samples DNA was enriched in 13C relative to soil, indicating microorganisms fractionated C during assimilation or preferentially used 13C enriched substrates. Enrichment of DNA in 15N relative to soil was not consistently observed, but there were significant differences between ?15N of DNA and ?15N of soil for three...
We characterized, at millimeter resolution, bacterial biomass, diversity, and vertical stratification of biological soil crusts in arid lands from the Colorado Plateau. Microscopic counts, extractable DNA, and plate counts of viable aerobic copiotrophs (VAC) revealed that the top centimeter of crusted soils contained atypically large bacterial populations, tenfold larger than those in uncrusted, deeper soils. The plate counts were not always consistent with more direct estimates of microbial biomass. Bacterial populations peaked at the immediate subsurface (1-2 mm) in light-appearing, young crusts, and at the surface (0-1 mm) in well-developed, dark crusts, which corresponds to the location of cyanobacterial populations....
The Utah sucker (Catostomus ardens) is endemic to the Bonneville Basin and the upper Snake River drainage in western North America, and is thought to hybridize with the federally endangered June sucker (Chasmistes liorus mictus) in Utah Lake (Bonneville Basin). Here we describe the discovery of a major subdivision in Utah suckers (4.5% mitochondrial sequence divergence) between the ancient Snake River drainage and the Bonneville Basin. This boundary has not previously been recognized in Utah suckers based on morphologic variation, but has been recently described in two endemic cyprinids in the region. Populations in valleys east of the Wasatch Mountains in Utah clustered with the Snake River populations, suggesting...
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Conclusions: Grizzly bear population fragmentation corresponded to the presence of settled mountain valleys and major highways. In these disturbed areas, the inter-area movements of female bears was affected more than for male bears. Without female connectivity, small subpopulations of grizzly bears are not viable over the long term. Thresholds/Learnings: Females grizzlies reduced their movement rates drastically when settlement increased to >20% of a given area. In highly settled areas (>50% settlement), both sexes demonstrated similar reductions in movement. Synopsis: Researchers studied the current state and potential causes of population fragmentation in grizzly bears over western Canada, the Greater Yellowstone...
Categories: Publication; Types: Citation, Map Service, OGC WFS Layer, OGC WMS Layer, OGC WMS Service; Tags: Alberta, British Columbia, Canadian Rockies, Chilcotin Ranges and Fraser Plateau, Clear Hills and Western Alberta Upland, All tags...
Although cyclosporine has high specificity for the immune system, immunosuppressive therapy with CsA is often complicated by nephrotoxicity. The main morphologic targets of CsA nephrotoxicity include the tubular epithelial and endothelial cells. These cells were investigated in vitro. CsA caused a dose- and time-dependent inhibition of cell growth, vacuolization and fatty change in adherent cells, detachment, and cell death. Inhibition of 3H-TdR incorporation in cells of both tubular epithelial and endothelial origin occurred between 3 microM and 10 microM. Electron microscopy studies revealed cellular swelling, dilatation of the endoplasmic reticulum, and the presence of lipid droplets and giant mitochondria. The...
Understanding climate change and its potential impact on species, populations and communities is one of the most pressing questions of twenty-first-century conservation planning. Palaeobiogeographers working on Cenozoic fossil records and other lines of evidence are producing important insights into the dynamic nature of climate and the equally dynamic response of species, populations and communities. Climatic variations ranging in length from multimillennia to decades run throughout the palaeo-records of the Quaternary and earlier Cenozoic and have been shown to have had impacts ranging from changes in the genetic structure and morphology of individual species, population sizes and distributions, community composition...
Freshwater mussels (unionids) are increasingly recognized as important providers of ecosystem services, yet are among the most endangered fauna in the world. Because unionids are generally sessile and require specific fish hosts for development and dispersal, they are particularly vulnerable to habitat degradation. Surprisingly, little is known about the distribution of genetic diversity in freshwater mussels and this gap has a negative impact on taxonomy, monitoring, conservation and ecological research in these species. Here, we focus on western North American Anodonta, one of only three genera known to exist in this broad landscape and which contains three highly divergent lineages. We describe phylogeographical...
We report the first simultaneous measurements of δ15N and δ13C of DNA extracted from surface soils. The isotopic composition of DNA differed significantly among nine different soils. The δ13C and δ15N of DNA was correlated with δ13C and δ15N of soil, respectively, suggesting that the isotopic composition of DNA is strongly influenced by the isotopic composition of soil organic matter. However, in all samples DNA was enriched in 13C relative to soil, indicating microorganisms fractionated C during assimilation or preferentially used 13C enriched substrates. Enrichment of DNA in 15N relative to soil was not consistently observed, but there were significant differences between δ15N of DNA and δ15N of soil for...
    map background search result map search result map Population fragmentation and inter-ecosystem movements of grizzly bears in western Canada and the northern United States. Population fragmentation and inter-ecosystem movements of grizzly bears in western Canada and the northern United States.