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991.
992.
Understanding the ecological process of population differentiation and identifying the molecular changes that contribute to adaptation is a central aspect of evolutionary biology. In this study we analyzed the geographic variation in allozyme allele frequencies (based on 15 enzyme systems representing 18 loci) across 18 populations of the butterfly Lycaena tityrus from different altitudes. Population genetic analyses showed that within population genetic diversity (e.g. mean number of alleles per loci: 1.8; expected heterozygosity: 12%) was within the typical value range for the Lepidoptera. The populations of L. tityrus investigated showed a remarkable genetic differentiation (FST : 0.065), being clearly divided into an alpine (high-altitude) and a non-alpine (low-altitude) cluster. This differentiation was almost entirely caused by variation at a single enzyme locus, PGI. Although the involvement of historical events cannot be ruled out, several lines of evidence suggest that the specific pattern of allozyme (and in this case particularly PGI) variation found is caused by thermal selection. For example, genetic variation was highly locus-specific rather than relatively uniform, as should be expected for effects of natural selection. Further, the PGI 2–2 genotype dominating in alpine (in contrast to low-altitude) populations is known to exhibit increased cold stress resistance and relatively long development times typical of alpine populations. Thus, PGI (or possibly a closely linked gene) is an obvious target for thermal selection in L. tityrus . This study exemplifies how allozyme analyses can be used to detect candidate loci likely to be under selection. 相似文献
993.
994.
Adam Felton Joern Fischer David B. Lindenmayer Rebecca Montague-Drake Arianne R. Lowe Debbie Saunders Annika M. Felton Will Steffen Nicola T. Munro Kara Youngentob Jake Gillen Phil Gibbons Judsen E. Bruzgul Ioan Fazey Suzi J. Bond Carole P. Elliott Ben C. T. Macdonald Luciana L. Porfirio Martin Westgate Martin Worthy 《Biodiversity and Conservation》2009,18(8):2243-2253
Recent reviews of the conservation literature indicate that significant biases exist in the published literature regarding
the regions, ecosystems and species that have been examined by researchers. Despite the global threat of climatic change,
similar biases may be occurring within the sub-discipline of climate-change ecology. Here we hope to foster critical thought
and discussion by considering the directions taken by conservation researchers when addressing climate change. To form a quantitative
basis for our perspective, we assessed 248 papers from the climate change literature that considered the conservation management
of biodiversity and ecosystems. We found that roughly half of the studies considered climate change in isolation from other
threatening processes. We also found that the majority of surveyed scientific publications were conducted in the temperate
forests of Europe and North America. Regions such as Latin America that are rich in biodiversity but may have low adaptive
capacity to climate change were not well represented. We caution that such biases in research effort may be distracting our
attention away from vulnerable regions, ecosystems and species. Specifically we suggest that the under-representation of research
from regions low in adaptive capacity and rich in biodiversity requires international collaboration by those experienced in
climate-change research, with researchers from less wealthy nations who are familiar with local issues, ecosystems and species.
Furthermore, we caution that the propensity of ecologists to work in essentially unmodified ecosystems may fundamentally hamper
our ability to make useful recommendations in a world that is experiencing significant global change. 相似文献
995.
Dmitri Demidov Susann Hesse Annegret Tewes Twan Rutten Jörg Fuchs Raheleh Karimi Ashtiyani Sandro Lein reas Fischer Gunter Reuter Andreas Houben 《The Plant journal : for cell and molecular biology》2009,59(2):221-230
The enzymological properties of AtAurora1, a kinase responsible for the cell cycle-dependent phosphorylation of histone H3 at S10, and its cross-talk with other post-translational histone modifications, were determined. In vitro phosphorylation of H3S10 by AtAurora1 is strongly increased by K9 acetylation, and decreased by K14 acetylation and T11 phosphorylation. However, S10 phosphorylation activity is unaltered by mono-, di- or trimethylation of K9. An interference of H3K9 dimethylation by SUVR4 occurs by a pre-existing phosphorylation at S10. Hence, cross-talk in plants exists between phosphorylation of H3S10 and methylation, acetylation or phosphorylation of neighbouring amino acid residues. AtAurora1 undergoes autophosphorylation in vivo regardless of the presence of substrate, and forms dimers in planta . Of the three ATP-competitive Aurora inhibitors tested, Hesperadin was most effective in reducing the in vivo kinase activity of AtAurora1. Hesperadin consistently inhibited histone H3S10 phosphorylation during mitosis in Arabidopsis cells, but did not affect other H3 post-translational modifications, suggesting a specific inhibition of AtAurora in vivo . Inactivation of AtAurora also caused lagging chromosomes in a number of anaphase cells, but, unlike the situation in mammalian cells, Hesperadin did not influence the microtubule dynamics in dividing cells. 相似文献
996.
Guido Achermann Theresa M. Ballard Francesca Blasco Pierre-Emmanuel Broutin Bernd Büttelmann Holger Fischer Martin Graf Maria-Clemencia Hernandez Peter Hilty Frédéric Knoflach Andreas Koblet Henner Knust Anke Kurt James R. Martin Raffaello Masciadri Richard H.P. Porter Heinz Stadler Andrew W. Thomas Gerhard Trube Jürgen Wichmann 《Bioorganic & medicinal chemistry letters》2009,19(19):5746-5752
Through iterative design cycles we have discovered a number of novel new classes where the imidazo[1,5-a][1,2,4]-triazolo[1,5-d][1,4]benzodiazepine was deemed the most promising GABAA α5 inverse agonist class with potential for cognitive enhancement. This class combines a modest subtype binding selectivity with inverse agonism and has the most favourable molecular properties for further lead optimisation towards a central nervous system (CNS) acting medicine. 相似文献
997.
998.
Joseph K. Bailey Jennifer A. Schweitzer Francisco úbeda Julia Koricheva Carri J. LeRoy Michael D. Madritch Brian J. Rehill Randy K. Bangert Dylan G. Fischer Gerard J. Allan Thomas G. Whitham 《Philosophical transactions of the Royal Society of London. Series B, Biological sciences》2009,364(1523):1607-1616
Using two genetic approaches and seven different plant systems, we present findings from a meta-analysis examining the strength of the effects of plant genetic introgression and genotypic diversity across individual, community and ecosystem levels with the goal of synthesizing the patterns to date. We found that (i) the strength of plant genetic effects can be quite high; however, the overall strength of genetic effects on most response variables declined as the levels of organization increased. (ii) Plant genetic effects varied such that introgression had a greater impact on individual phenotypes than extended effects on arthropods or microbes/fungi. By contrast, the greatest effects of genotypic diversity were on arthropods. (iii) Plant genetic effects were greater on above-ground versus below-ground processes, but there was no difference between terrestrial and aquatic environments. (iv) The strength of the effects of intraspecific genotypic diversity tended to be weaker than interspecific genetic introgression. (v) Although genetic effects generally decline across levels of organization, in some cases they do not, suggesting that specific organisms and/or processes may respond more than others to underlying genetic variation. Because patterns in the overall impacts of introgression and genotypic diversity were generally consistent across diverse study systems and consistent with theoretical expectations, these results provide generality for understanding the extended consequences of plant genetic variation across levels of organization, with evolutionary implications. 相似文献
999.
Kiranmai Durvasula Kaemwich Jantama Kyle Fischer Adrian Vega Ben Koopman Spyros A. Svoronos 《Biotechnology progress》2009,25(4):973-979
Paracoccus pantotrophus expresses two nitrate reductases—membrane bound nitrate reductase (Nar) and periplasmic nitrate reductase (Nap). In growth experiments with two denitrifying species (Paracoccus pantotrophus and Alcaligenes eutrophus) that have both Nap and Nar and two species (Pseudomonas denitrificans and Pseudomonas fluorescens) with Nar only, it was found that diauxic lag is shorter for bacteria that express Nap. In P. pantotrophus, napEDABC encodes the periplasmic nitrate reductase. To analyze the effect of Nap on diauxic lag, the nap operon was deleted from P. pantotrophus. The growth experiments with nap? mutant resulted in increased diauxic lag when switched from aerobic to anoxic respiration, suggesting Nap is responsible for shorter lags and helps in adaptation to anoxic metabolism after transition from aerobic conditions. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009 相似文献
1000.
Eva Große Maestrup Christian Wiese Dirk Schepmann Achim Hiller Steffen Fischer Matthias Scheunemann Peter Brust Bernhard Wünsch 《Bioorganic & medicinal chemistry》2009,17(10):3630-3641
Several 3H-spiro[[2]benzofuran-1,4′-piperidines] bearing a p-fluorobenzyl residue at the N-atom and various substituents in position 3 of the benzofuran system were synthesized. The crucial reaction steps are the addition of a lithiated benzaldehyde derivative to the p-fluorobenzylpiperidone 5 and the BF3·OEt2 catalyzed substitution of the methoxy group of 2a by various nucleophiles. Structure–affinity relationship studies revealed that compounds with two protons (2d), a methoxy group (2a), and a cyano group (2e) in position 3 possess subnanomolar σ1 affinity (Ki = 0.18 nM, 0.79 nM, 0.86 nM) and high selectivity against the σ2 subtype. The metabolites of 2a, 2d, and 2e, which were formed upon incubation with rat liver microsomes, were identified. Additionally, the rate of metabolic degradation of 2a, 2d, and 2e was determined and compared with the degradation rate of the non-fluorinated spirocyclic compound 1. For the synthesis of the potential PET tracers [18F]2a and [18F]2e two different radiosynthetic approaches were followed. 相似文献