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111.
Alex Beharav Roi Ben-David Janusz Malarz Anna Stojakowska Klaudia Michalska Ivana Doležalová Aleš Lebeda Wanda Kisiel 《Biochemical Systematics and Ecology》2010
A comparative phytochemical study of seven sesquiterpene lactones in natural populations of the wild lettuce Lactuca aculeata Boiss. (Asteraceae) was performed, based on 23 accessions derived from eight, two, and single localities from Israel, Jordan, and Turkey, respectively. The compounds were profiled and quantified in leaves and roots of the plants, grown from achenes (cypselas) in a greenhouse under controlled conditions, using reverse phase HPLC with on-line photodiode array detector. In the present study, L. aculeata was confirmed as a taxon strongly characterized by four dominant sesquiterpene lactones: 8-deoxylactucin, jacquinelin, crepidiaside B and lactuside A. An analysis of quantitative results of these four constituents led to the following conclusions: (i) the sesquiterpene lactone contents varied significantly, mainly within the populations; however, for two variables (crepidiaside B and lactuside A in root samples) the contents varied mostly between populations, (ii) these differences are likely to be genetically controlled since all accessions were grown under standardized glasshouse conditions. Accessions containing high levels of some sesquiterpene lactones were found in several populations. These traits should be conserved in situ and ex situ and utilized in further research and lettuce improvement. 相似文献
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Friend virus-induced erythroleukemia and the multistage nature of cancer 总被引:43,自引:0,他引:43
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Deborah A. Rocque Merav Ben-David Ronald P. Barry Kevin Winker 《Journal of Ornithology》2006,147(2):395-404
Geographic origins of populations and migration patterns of several vertebrate and invertebrate species have been inferred
from geographically distinct isotopes
in their tissues. To test the hypothesis that feathers grown on different continents would reflect continental differences
of δD in precipitation and have significantly different stable isotope ratios, we analyzed stable isotopes in two generations
of feathers from three bird species (American and Pacific golden-plovers, Pluvialis dominica and P. fulva, and northern wheatears
Oenanthe
oenanthe) that breed in North America and winter in South America, the South Pacific and Asia, and Africa. We found significant differences
in stable isotope signatures between summer- and winter-grown feathers in the plovers, and our use of two generations of feathers
provided similar variation to that reported in studies using larger sample sizes. In
contrast to plovers, no differences were detected in isotope values between summer- and winter-grown feathers in wheatears.
Discriminant analyses separated 80% of summer- and winter-grown feathers for each plover species. Nonetheless, an “assignment
with exclusion” method adapted from population genetics to impart a measure of confidence in assigning individuals to groups
of origin resulted in an overall accuracy among plovers of only 41%, compared with a 63% assignment accuracy when the exclusion
criterion was removed. Thus, we were unable to accurately assign feathers to origin of growth on the continental scale. Moreover,
using δD expectations for North America, we were unable to assign summer-grown plover feathers to within better than several
thousand kilometers of their true origins. We urge researchers to carefully consider the ecology and physiology of their study
organisms, statistical methodology, and the interpretation of results when using stable isotopes to infer the geographic origins
of feather growth. 相似文献
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Fecal genotyping reveals demographic variation in river otters inhabiting a contaminated environment
Daniel A. Guertin Merav Ben-David Alton S. Harestad John E. Elliott 《The Journal of wildlife management》2012,76(8):1540-1550
The deposition and accumulation of persistent contaminants into coastal systems can have lingering negative consequences for wildlife populations and their habitats. Using multi-locus genotyping of non-invasively collected feces, we assessed the effects of such pollution on reproduction, survival, genetic variability, and abundance of river otters (Lontra canadensis) along a gradient of urban–industrial development on southern Vancouver Island, British Columbia, Canada. Genetic analyses indicated a pattern consistent with small-scale structuring, with individuals partitioned into 2 local subpopulations—those identified in the contaminated harbors of southern Vancouver Island and points west (Colwood/Harbors), and those inhabiting uncontaminated habitat east of the harbors (Oak Bay). Genetic and demographic analyses for the 2 clusters provide strong support for the conclusion that, despite contamination concerns, Colwood/Harbors river otters exhibited acceptable levels of survival and successfully reproduced (i.e., high levels of relatedness, high self-recruitment, and high emigration). However, our data indicate that the Colwood/Harbors area constitutes lower quality habitat supporting lower densities of otters, especially during winter, and excess individuals produced in that region emigrate to other areas. Immigration into Colwood/Harbors, however, seems limited, possibly because of behavioral aversion of non-habituated otters to anthropogenic disturbance associated with the harbors and limited optimal otter habitat. Our findings suggest that the effects of chronic contaminant exposure at the population level may be inadvertently mitigated through the behavioral decisions of individuals to avoid poor quality habitats. We conclude that populations of river otters can persist in and around locally contaminated sites if relatively less disturbed and contaminated habitats remain in the vicinity of the affected areas. © 2012 The Wildlife Society. 相似文献