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991.
There is growing support for the general notion that the drivers of invasion success often shift from biotic to abiotic factors
with increasing spatial scale. Most of this research, however, has been conducted on a single trophic level; i.e. it has primarily
looked at how the diversity of native competitors may influence invasion success. Less attention has been paid to understanding
how native prey diversity may influence the invasion success of exotic predators and whether such biotic factors are scale-dependent.
We used a hierarchical spatial survey of 17 stream communities to test whether native prey diversity, along with native prey
biomass, algal resource abundance and annual stream discharge, influenced the abundance of an exotic crayfish predator, and
whether the importance of these factors were scale-dependent. We used a hierarchical generalized linear model to evaluate
the influence of these community and stream characteristics on exotic crayfish abundance at both the transect scale (1 m2) and the stream scale (400 m2). Our results indicated that at the stream scale, high stream discharge significantly limited invader abundance. However,
at the smaller transect scale, native prey biomass was a significant driver of invasion success and positively correlated
with invader abundance. We suggest that our results add to the emerging pattern that abiotic processes are stronger determinants
of invasion success at large spatial scales, whereas biotic processes become more important with decreasing spatial scale.
However, for predator invasions, prey biomass, not prey diversity may be a more important for driver of invasion success at
small spatial scales. 相似文献
992.
Halil Erhan Eroğlu Ahmet Aksoy Ergin Hamzaoğlu Ümit Budak Sevil Albayrak 《Cytotechnology》2009,59(1):65-72
Helichrysum Mill. (Asteraceae) species have been used in folk medicine for thousands of years in the world. The in vitro cytogenetic
effects in human lymphocytes of nine Helichrysum taxa used in Turkey folk medicine were investigated. Blood samples were obtained from healthy donors, non-smoking volunteers,
which were incubated and exposed to increasing concentrations of methanol extracts of Helichrysum taxa (0.01, 0.05, 0.1, 0.5 and 1 mg/mL). The inhibitory effects of H. stoechas (L.) Moench subsp. barrelieri (Ten.) Nyman, H. armenium DC. subsp. armenium, H. armenium DC. subsp. araxinum (Kirp.) Takht., H. plicatum DC. subsp. plicatum, H. compactum Boiss. and H. artvinense P.H.Davis & Kupicha on the mitotic index and replication index indicate that these taxa can have genotoxic and mutagenic
effects. They should therefore not be used freely in alternative medicine although their antiproliferative activity may suggest
anticarcinogenic properties. Increase effects of H. stoechas subsp. barrelieri, H. armenium subsp. armenium, H. armenium subsp. araxinum, H. chasmolycicum P.H.Davis, H. plicatum subsp. plicatum, H. compactum and H. artvinense on the micronucleus rates showed that these taxa can have genotoxic and carcinogenic effects. 相似文献
993.
994.
PiggyBac system has been shown to have a high efficiency to mediate gene transfer. However, there are no reports on its efficiency to mediate multiplex transgenes in mouse embryonic stem cells. Here we first established an immortalized feeder cell line by introducing four antibiotic resistance genes simultaneously into the original SNL 76/7 feeder cell line utilizing the PiggyBac system. This is the feeder cell line with the most diverse types of antibiotic resistance genes reported so far, which will enable researchers to perform simultaneous multiplex gene transfer or gene targeting experiments in ES cells. With such feeder cell line, we were able to quantitatively characterize the transposition efficiency of PiggyBac system in mouse ES cells using five transposons carrying different inducible fluorescence proteins and antibiotic resistance genes, and the efficiency ranged from about 2% for one transposon to 0.5% for five transposons. The highly efficient multiplex gene transfer mediated by PiggyBac will no doubt provide researchers with more choices in biomedical research and development. 相似文献
995.
Identification,Design and Bio-Evaluation of Novel Hsp90 Inhibitors by Ligand-Based Virtual Screening
JianMin Jia XiaoLi Xu Fang Liu XiaoKe Guo MingYe Zhang MengChen Lu LiLi Xu JinLian Wei Jia Zhu ShengLie Zhang ShengMiao Zhang HaoPeng Sun QiDong You 《PloS one》2013,8(4)
Heat shock protein 90 (Hsp90), whose inhibitors have shown promising activity in clinical trials, is an attractive anticancer target. In this work, we first explored the significant pharmacophore features needed for Hsp90 inhibitors by generating a 3D-QSAR pharmacophore model. It was then used to virtually screen the SPECS databases, identifying 17 hits. Compound S1 and S13 exhibited the most potent inhibitory activity against Hsp90, with IC50 value 1.61±0.28 μM and 2.83±0.67 μM, respectively. Binding patterns analysis of the two compounds with Hsp90 revealed reasonable interaction modes. Further evaluation showed that the compounds exhibited good anti-proliferative effects against a series of cancer cell lines with high expression level of Hsp90. Meanwhile, S13 induced cell apoptosis in a dose-dependent manner in different cell lines. Based on the consideration of binding affinities, physicochemical properties and toxicities, 24 derivatives of S13 were designed, leading to the more promising compound S40, which deserves further optimization. 相似文献
996.
Torben Greve 《Acta veterinaria Scandinavica》2004,45(Z1):S13
Xenotransplantation of organs from the large domestic species will only be successful if the donor animals have been genetically modified, in particular regarding the α-Gal epitope, certain human complements (CD55 and CD59) and/or H-transferase. This requires, among other things, major embryo-technological efforts, and the rate of success is still far from an acceptable level in the domestic species. It is currently poor, but the progress is very good. In this brief review certain embryo-technological problems will be addressed with the focus on the pig as potential organ donor. In addition, certain views of the Danish ad hoc Committee on Gene Technology on xenotransplantation will be presented in this context as they are supposed to mirror the concern and the views of the issues important for the public and each individual. 相似文献
997.
Molecular tools were used to evaluate the hybrid status of a specimen with intermediate colour pattern between Halichoeres bivittatus and Halichoeres garnoti from Belize. Phylogenetic analyses of the two species, eight Halichoeres species from new and old world lineages and two outgroups showed that the study species are closely related and that H. garnoti is the maternal contributor to the putative hybrid specimen, based on partial mitochondrial COI data. Direct sequencing of
Intron 1 of the nuclear ribosomal protein S7 identified H. bivittatus as sister to H. garnoti with the putative hybrid specimen in an intermediate position, due to heterozygosity at nucleotides alternatively fixed in
the two putative parent species. This is consistent with the hybrid status of the specimen, with parental contributions from
both H. garnoti and H. bivittatus. These results, combined with no evidence of introgression between the two parent species (based on the mtDNA and the single
investigated nuclear marker) and the biogeography and ecology of these species suggests that this is a rare event with minimal
evolutionary implications. 相似文献
998.
999.
Gerald Busch 《Bioenergy Research》2012,5(3):584-605
Based on regional stakeholder preferences and planning guidelines as allocation criteria for SRC, this study aims at providing
a transparent approach to evaluate multiple environmental effects and the regional significance of SRC systems. Using the
example of two poplar SRC-systems (4-year rotation, 9-year rotation) the potential effects on ground water supply, wind erosion,
and biodiversity aspects are evaluated in comparison to arable land for two selected municipalities in the district of Uelzen,
Germany. Building on fuzzy membership functions and simple fuzzy-logic rules, the qualitative multi-criteria assessment is
transparent and easily to adapt. This approach is transferable to other regions and spatial levels, since it derives from
commonly available data and scientific evidence. Results show that implementation of SRC could provide multiple beneficial
environmental effects, especially in areas with low landscape heterogeneity. The tools provided allow for a multi-criteria
evaluation of environmental effects, and reveal the sensitivity to distinct allocation patterns. Physiographical conditions
of the study area implicate a preference for mini-SRC systems. This is supported by smaller decline of annual deep percolation
water compared to maxi-SRC. On average, decline in groundwater recharge of mini-SRC (92mm a−1) is comparable to irrigated arable land (80mm a−1), which is common practice in the study area. Currently, the utilization of beneficial environmental SRC effects is quite
limited, since only 3 % of arable land is suitable for SRC implementation regarding farmers’ preferences for SRC allocation.
Allocation preferences could however change substantially with increasing incentives for SRC, e.g., due to regional bioenergy
schemes or “Greening” initiatives within the European Common Agricultural Policy, which is to be reformed by 2013. 相似文献
1000.
Paul Bangirana Peter Allebeck Michael J Boivin Chandy C John Connie Page Anna Ehnvall Seggane Musisi 《BMC neurology》2011,11(1):96