Population differentiation and genetic variation inform translocation decisions for Liatris scariosa var. novae-angliae, a rare New England grassland perennial     

Kelly Gravuer  Eric von Wettberg  Johanna Schmitt 《Biological conservation》2005,124(2):155-167

Augmentation of small rare species populations is sometimes suggested on genetic grounds. However, outbreeding depression via dilution of local adaptation or break-up of genomic coadaptation may occur. These effects depend on the causes of population divergence. Here, we compare genetic measures of population divergence in Liatris scariosa var. novae-angliae, a rare New England perennial. We measured G_ST, neutral marker subdivision, and Q_ST, quantitative subdivision of propagule and juvenile plant traits. G_ST was relatively high. Q_ST for leaf shape exceeded G_ST, indicating local adaptation, while Q_ST for other traits fell within or below the G_ST range. Local adaptation appears low for juvenile traits, although the high G_ST cautions against translocation because of potential coadaptation. If translocation is still required, however, donor populations should contain high quantitative genetic diversity. We assess population size and allozyme diversity as predictors of quantitative genetic variation, but find these poor proxies for direct measurement.  相似文献   

Copper Accumulation in a Reservoir Ecosystem Following Copper Sulfate Treatment (St. Germain Les Belles, France)     

Eric van Hullebusch  Philippe Chatenet  Véronique Deluchat  Philippe M. Chazal  Didier Froissard  Michel Botineau  Axel Ghestem  Michel Baudu 《Water, air, and soil pollution》2003,150(1-4):3-22

Copper sulfate (CuSO₄) addition to freshwater for phytoplankton control has been practiced for decades, and remains the most effective algicidal treatment for numerous managed water bodies. A reservoir in the centre of France was the site for an investigation of copper distribution in aquatic systems after a copper sulfate treatment. Results of monitoring showed a rapid conversion of dissolved Cu to particulate forms, with significant accumulation in the sediments. Total sediment Cu content increased from approximately 37.7 to 45.4 μg g^-1 dry weight after the first treatment. Sequential extraction suggested that a significant portion of the sediment-borne Cu was associated with the organic fraction which may release Cu to the water column, although significant release would occur only under extreme changes in water chemistry. Based upon measured Cu concentrations, flows at the down-stream water, and known mass applied during treatment, mass balance calculations indicated that approximately 17% of the Cu was exported from the reservoir over a 70 day period following a 196 μg L^-1 Cu²⁺ (as CuSO₄·5H₂O) treatment.Copper bioaccumulation by a moss, Fontinalis antipyretica in the down-stream water showed that it was possible to distinguish between a treated and an untreated area. The impact of copper treatmentin the down-stream reservoir could be followed using mosses. There is a distance effect which could be exploited to determine potential copper impact for example. The largest amount of copper was probably adsorbed on downstream sediment or lost in running water. Thirty days after copper sulfate addition, Fontinalis still indicatedcopper exposure.  相似文献   

Assessment of genetic diversity among African cassava Manihot esculenta Grantz accessions resistant to the cassava mosaic virus disease using SSR markers   总被引：1，自引：0，他引：1  

Yvonne Lokko  Alfred Dixon  Sam Offei  Eric Danquah  Martin Fregene 《Genetic Resources and Crop Evolution》2006,53(7):1441-1453

A study was conducted to determine the extent of genetic diversity among African cassava (Manihot esculenta Crantz) accessions resistant to the cassava mosaic virus disease (CMD), using simple sequence repeat (SSR) markers. The accessions included a breeding stock (clone 58308), five improved lines, 62 CMD resistant and 10 CMD susceptible landraces. Genetic diversity was assessed among accessions in five cluster groups derived from UPGMA analysis on data from 18 SSR primer pairs. Average gene diversity, He, was high in all cluster groups, with an average heterozygosity of 0.591 ± 0.061. The estimator of inbreeding Fis revealed a low level of inbreeding within groups and averaged −0.262 ± 0.142. Gene diversity among all accessions was 51.4% and gene diversity within cluster groups was 46.6%, while 4.8% was due to diversity between the different cluster groups. The amount of genetic differentiation measured by Gst and Fst were 9.6% and 12.1% respectively, indicating a weak genetic structure.  相似文献   

Determination of the conjugated linoleic acids in cow's milk fat by Fourier transform Raman spectroscopy   总被引：1，自引：0，他引：1  

Meurens M  Baeten V  Yan SH  Mignolet E  Larondelle Y 《Journal of agricultural and food chemistry》2005,53(15):5831-5835

The collective term "conjugated linoleic acid" or "CLA" generally refers to a mixture of conjugated positional and geometric isomers of linoleic (cis-9,cis-12-octodecadienoic) acid. In nature, these isomers are mainly formed in the rumen by biohydrogenation of polyunsaturated fatty acids. This study concerns a first trial of CLA determination in cow's milk fat by Raman spectroscopy. The spectra of pure cis-9-oleic, cis-9,cis-12-linoleic, cis-9,trans-11-linoleic, and trans-10,cis-12-linoleic acids have been examined in comparison with the spectra of selected milk-fat samples containing between 0 and 3% of CLA. The trial of CLA determination by Raman spectroscopy on cow milk fat has reached its objective with the two following results. First, the examination of the Raman spectra allows to identify three specific Raman signals of the chemical bonds associated to the cis,trans conjugated C=C in the rumenic and trans-10,cis-12-octodecadienoic acids at 1652, 1438, and 3006 cm(-1). Second, the calibration of Raman spectrometer for the CLA determination has indicated that these three specific signals suit very well for the accurate and reliable measurement of CLA concentration in milk fat. To our knowledge, the present study is the first successful attempt to determine the CLA content of milk fat by a spectrophotometric method.  相似文献   

Assessment of shoreline vegetation in relation to use by molting black brant Branta bernicla nigricans on the Alaska coastal plain     

Milton W. Weller  K.C. Jensen  Eric J. Taylor  Mark W. Miller  Karen S. Bollinger  Dirk V. Derksen  Daniel Esler  Carl Markon 《Biological conservation》1994,70(3):219-225

To evaluate the importance of large thaw lakes on the Alaska Coastal Plain for molting Pacific black brant Branta bernicla nigricans, distribution and life form of shoreline vegetation were assessed using several scales: satellite imagery, point-intercept transects, cover quadrats, and a parameter for water regime. Brant population and distribution estimates from aerial surveys were used to classify large lakes into high, moderate, and low use. Correlations between brant and abundance of their preferred feeding site — moss flats — were best demostrated by satellite imagery. Intercepts and cover ratings were not correlated, presumably because these techniques were less efficient at assessing area. General observations suggested that the presence of islands, large ice floes, and possibly other physical attributes of the habitat, influenced brant distribution. This area is unique because of low-lying, drained-lake basins that have ideal combinations of moss flats and large water areas where brant seek protection disturbance is vital to the success of this declining species because alternate habitats may not be available elsewhere on the Coastal Plain. in water or on ice floes. Protection of the area from  相似文献   

Genetic mapping in Lilium: mapping of major genes and quantitative trait loci for several ornamental traits and disease resistances     

Arwa Shahin  Paul Arens  Adriaan W. Van Heusden  Gerard Van Der Linden  Martijn Van Kaauwen  Nadeem Khan  Henk J. Schouten  W. Eric Van De Weg  Richard G. F. Visser  Jaap M. Van Tuyl 《Plant Breeding》2011,130(3):372-382

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Cattle, ethanol, and biogas: Does closing the loop make economic sense?   总被引：1，自引：0，他引：1  

Eric A. DeVuyst  Scott W. PryorGreg Lardy  Wallace EideRon Wiederholt 《Agricultural Systems》2011,104(8):609-614

The recent surge in US ethanol production has led to an increase in the amount of byproduct feed available to cattle producers. The impetus behind the increase in ethanol production is US policy to increase the production and use of renewable fuels. Manure from cattle production can also be used to produce a renewable fuel: methane. By co-locating a cattle feedlot with an existing ethanol plant, there may be synergies between ethanol, methane and cattle production. Byproduct from the ethanol plant can be fed to feeder cattle, manure from the cattle used in methane production, and the methane used as an energy source in the ethanol plant. Alternatively, methane can be used to generate electricity. We investigate the economic advisability of these systems. Using cost estimates for construction and operating a feedlot and anaerobic digester for methane production, we project revenues and costs over a 20-year time period. Our findings are consistent with studies that have considered just cattle production and methane production. The investment required to build a slatted-floor feedlot and concrete anaerobic digester cannot be justified under existing economic conditions. An increase in renewable fuel/electricity subsidies of at least $0.053 per kW h or $72 per 1000 m³ of methane are required to just break even when methane is used to produce electricity or is burned for thermal energy, respectively.  相似文献   

Genome-sequencing anniversary. First steps on a long road     

Schadt E 《Science (New York, N.Y.)》2011,331(6018):691

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Virology. Rafting with Ebola     

Freed EO 《Science (New York, N.Y.)》2002,296(5566):279

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Conservation policy. House revises Endangered Species Act     

Stokstad E 《Science (New York, N.Y.)》2005,310(5745):32

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