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排序方式: 共有107条查询结果,搜索用时 46 毫秒
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Epigenetics refers to heritable changes in gene expression that are independent of alterations in DNA sequence. It is now accepted that disruption of epigenetic mechanisms plays a key role in the pathogenesis of cancer: culminating in altered gene function and malignant cellular transformation. DNA methylation and histone modifications are the most widely studied changes but non-coding RNAs such as miRNAs are also considered part of the epigenetic machinery. The insulin-like growth factor (IGF) axis is composed of two ligands, IGF-I and –II, their receptors and six high affinity IGF binding proteins (IGFBPs). The IGF axis plays a key role in cancer development and progression. As IGFBP genes have consistently been identified among the most common to be aberrantly altered in tumours, this review will focus on epigenetic regulation of IGFBP-3 in cancer for which the majority of evidence has been obtained. 相似文献
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Andrey Zuev Kerstin Heidemann Vladislav Leonov Ina Schaefer Stefan Scheu Andrei Tanasevitch Alexei Tiunov Sergey Tsurikov Anton Potapov 《Ecological Entomology》2020,45(6):1346-1356
- Generalistic interactions between predator and prey may vary with ecosystem type, predator traits, and prey traits, but the interplay of these factors has not been assessed in ground food webs.
- We investigated trophic interactions of ground-dwelling spiders across eight forests in European Russia associated with body size, hunting strategy, microhabitat specialization, potential prey type, potential prey population density, and forest type (coniferous vs. broadleaved). We analyzed 128 individual spiders, including juveniles, all identified to the family level with two complementary methods: molecular gut content analysis, and stable isotope analysis of carbon and nitrogen.
- The results suggest that feeding frequency of spiders is affected by predator body size and by selection of certain prey type. Stable isotope analysis showed similar trophic niches among spider families, varying moderately with forest type. Larger spiders had higher Δ13C values than smaller ones, but similar Δ15N values, suggesting that different size classes of spiders belong to different food chains. Results based on stable isotope and molecular gut content analyses were weakly linked, indicating them targeting different trophic niche dimensions.
- At least for the group-level interactions, family identity and hunting strategy of predator has little predictive power while predator body size and prey traits affected trophic niche dimensions calling for future studies in this direction. Large spiders feed more and rely on different basal resources than small spiders, suggesting that including small species and juveniles provides a more comprehensive picture of food web organization.
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Zueva A. I. Kachalkin A. V. Maksimova I. A. Van Thinh Nguyen Tiunov A. V. 《Microbiology》2021,90(4):489-499
Microbiology - Yeast populations were investigated for the following substrates associated with termitaria of five termite species occurring in the Cat Tien National Park (south Vietnam): nest... 相似文献
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Alexei V. Tiunov Cindy M. Hale Andrew R. Holdsworth Tamara S. Vsevolodova-Perel 《Biological invasions》2006,8(6):1223-1234
We examine the patterns of expansion of exotic European earthworms in northeastern Europe and the western Great Lakes region of North America. These areas share many ecological, climatic and historical characteristics and are devoid of indigenous earthworm fauna due to Quaternary glaciations. These regions are being colonized by a similar suite of exotic lumbricid species and it is unlikely that this is the result of chance, but rather indicates that these species have particular characteristics making them successful invaders. The present macro-scale distributions of earthworm species in northern Russia show little connection to the pattern of the last glaciation. Rather, the primary factors that determine the current distributions of earthworm species include climatic conditions, the life history traits of different earthworm species, the suitability of habitat and intensity and patterns of human activity. In the western Great Lakes region of North America, there are three primary factors affecting current distributions of exotic earthworm species including the patterns of human activity and land use practices, the composition of particular source populations of earthworms associated with different vectors of transport and the soil and litter properties of habitats across the region. Disturbance of a habitat does not appear to be a prerequisite to the invasion and establishment of exotic earthworms. Analysis of the macro-scale distributions of Lumbricidae species in northeastern Europe may provide important insights into the potential of invasive European earthworm species to spread in North America, and identify potentially invasive species. 相似文献
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Anton M. Potapov Eugenia E. Semenina Alexander V. Kurakov Alexei V. Tiunov 《Ecological Research》2013,28(6):1069-1079
Correctly estimating the trophic fractionation factors (Δ15N and Δ13C) in controlled laboratory conditions is essential for the application of stable isotope analysis in studies on the trophic structure of soil communities. Laboratory experiments usually suggest large 15N/14N and small 13C/12C trophic fractionation, but in field studies litter-dwelling microarthropods and other invertebrates are consistently enriched in 13C relative to plant litter. In the present study, we report data from two laboratory experiments investigating both fungi–collembolans and litter–fungi–collembolans systems. In the fungi–collembolans system, Δ15N and Δ13C averaged 1.4 ± 0.1 and 1.0 ± 0.2 ‰, respectively. In microcosms with fungi-inoculated litter, the difference in δ15N between collembolans and plant litter averaged 1.5 ± 0.2 ‰, confirming the relatively small 15N/14N trophic fractionation at the basal level of detrital foodwebs reported in numerous field studies. In full agreement with field observations, the difference in δ13C between bulk litter and collembolans in laboratory microcosms averaged 3.6 ± 0.1 ‰ and only little depended on collembolan species identities or the presence of water-soluble compounds in the litter. We conclude that increased δ13C values typical of litter-dwelling decomposers are largely determined by an increased 13C content in saprotrophic microorganisms. 相似文献
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MP Lisovoi NM Lesovoy GI Vasechko 《Archives Of Phytopathology And Plant Protection》2013,46(2):123-127
A new method of selection of the winter wheat varieties has been tested for resistance to the pest insects' complex by the traits of plants that are the markers of plant resistance. It makes it possible to use this method from year to year independently of the pests' density. 相似文献
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