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排序方式: 共有130条查询结果,搜索用时 203 毫秒
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Summary Foliar pubescence in the mexican madrone (Arbutus xalapensis H.B.K.) is an extremely variable character. Leaf specimens of pilose and glabrous madrones showed a similar composition of major secondary compounds. On the other hand, sympatric pilose and glabrous individuals were found to support significantly different insect guilds. Insect preference was strongly associated to mouthpart anatomy. Chewing and gall-forming insects were significantly more abundant on glabrous trees while sucking insects were more common on pilose trees. Additionally, parasitation of sucking insects was lower on pilose trees, possibly because the plant trichomes provide protection against parasitoids. 相似文献
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N. Belén Rumie Vittar María Julia Lamberti María Florencia Pansa Renzo E. Vera M. Exequiel RodriguezI. Sol Cogno Laura N. Milla SanabriaViviana A. Rivarola 《生物化学与生物物理学报:癌评论》2013
As with natural ecosystems, species within the tumor microenvironment are connected by pairwise interactions (e.g. mutualism, predation) leading to a strong interdependence of different populations on each other. In this review we have identified the ecological roles played by each non-neoplastic population (macrophages, endothelial cells, fibroblasts) and other abiotic components (oxygen, extracellular matrix) directly involved with neoplastic development. A way to alter an ecosystem is to affect other species within the environment that are supporting the growth and survival of the species of interest, here the tumor cells; thus, some features of ecological systems could be exploited for cancer therapy. We propose a well-known antitumor therapy called photodynamic therapy (PDT) as a novel modulator of ecological interactions. We refer to this as “ecological photodynamic therapy.” The main goal of this new strategy is the improvement of therapeutic efficiency through the disruption of ecological networks with the aim of destroying the tumor ecosystem. It is therefore necessary to identify those interactions from which tumor cells get benefit and those by which it is impaired, and then design multitargeted combined photodynamic regimes in order to orchestrate non-neoplastic populations against their neoplastic counterpart. Thus, conceiving the tumor as an ecological system opens avenues for novel approaches on treatment strategies. 相似文献
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Hyalella faxoni Stebbing, 1903 from Costa Rica is redescribed. The species was previously in the synonymy of Hyalella azteca (Saussure, 1858). The morphological differences between these two species are discussed. 相似文献
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Kim HU Cotter R Johnson S Senda M Dodds P Kulikauska R Tang W Ezcura I Herzmark P McCormick S 《Plant molecular biology》2002,50(1):1-16
We previously characterized LePRK1 and LePRK2, pollen-specific receptor kinases from tomato (Muschietti et al., 1998). Here we identify a similar receptor kinase from maize, ZmPRK1, that is also specifically expressed late in pollen development, and a third pollen receptor kinase from tomato, LePRK3. LePRK3 is less similar to LePRK1 and LePRK2 than either is to each other. We used immunolocalization to show that all three LePRKs localize to the pollen tube wall, in partially overlapping but distinct patterns. We used RT-PCR and degenerate primers to clone homologues of the tomato kinases from other Solanaceae. We deduced features diagnostic of pollen receptor kinases and used these criteria to identify family members in the Arabidopsis database. RT-PCR confirmed pollen expression for five of these Arabidopsis candidates; two of these are clearly homologues of LePRK3. Our results reveal the existence of a distinct pollen-specific receptor kinase gene family whose members are likely to be involved in perceiving extracellular cues during pollen tube growth. 相似文献
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Holmgren M Scheffer M Ezcurra E Gutiérrez JR Mohren GM 《Trends in ecology & evolution》2001,16(2):89-94
New studies are showing that the El Ni?o Southern Oscillation (ENSO) has major implications for the functioning of different ecosystems, ranging from deserts to tropical rain forests. ENSO-induced pulses of enhanced plant productivity can cascade upward through the food web invoking unforeseen feedbacks, and can cause open dryland ecosystems to shift to permanent woodlands. These insights suggest that the predicted change in extreme climatic events resulting from global warming could profoundly alter biodiversity and ecosystem functioning in many regions of the world. Our increasing ability to predict El Ni?o effects can be used to enhance management strategies for the restoration of degraded ecosystems. 相似文献
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Cecilia Ezcurra 《Brittonia》1998,50(3):339-342
A new species,Ruellia woolstonii C. Ezcurra from eastern Paraguay, is described, illustrated, and compared to related species.
Resumen Una nueva especie,Ruellia woolstonii C. Ezcurra de Paraguay oriental, se describe, ilustra, y compara con especies relacionadas.相似文献