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991.
Mutolo MJ Morris KJ Leir SH Caffrey TC Lewandowska MA Hollingsworth MA Harris A 《Matrix biology》2012,31(5):285-289
Non-fibrillar collagen XV is a chondroitin sulfate modified glycoprotein that is associated with the basement membrane zone in many tissues. Its precise functions remain to be fully elucidated though it clearly plays a critical role in the structural integrity of the extracellular matrix. Loss of collagen XV from the basement membrane zone precedes invasion of a number of tumor types and we previously showed that collagen XV functions as a dose-dependent suppressor of tumorigenicity in cervical carcinoma cells. The carboxyl terminus of another non-fibrillar collagen (XVIII) is cleaved to produce endostatin, which has anti-angiogenic effects and thus may act as a tumor suppressor in vivo. Since collagen XV has structural similarity with collagen XVIII, its C-terminal restin domain could confer tumor suppressive functions on the molecule, though our previous data did not support this. We now show that expression of collagen XV enhances the adhesion of cervical carcinoma cells to collagen I in vitro as does the N-terminus and collagenous regions of collagen XV, but not the restin domain. Destruction of a cysteine residue in the collagenous region that is critical for intermolecular interactions of collagen XV abolished the enhanced adhesion to collagen I. Finally, we demonstrate that unlike full length collagen XV, expression of the restin domain alone does not suppress tumorigenicity of cervical carcinoma cells in vivo; hence, this process is dependent on functions and interactions of other parts of the protein. 相似文献
992.
993.
Magdalena Bohutínsk Vinzenz Handrick Levi Yant Roswitha Schmickl Filip Kol Kirsten Bomblies Pirita Paajanen 《Molecular biology and evolution》2021,38(5):1980
A sudden shift in environment or cellular context necessitates rapid adaptation. A dramatic example is genome duplication, which leads to polyploidy. In such situations, the waiting time for new mutations might be prohibitive; theoretical and empirical studies suggest that rapid adaptation will largely rely on standing variation already present in source populations. Here, we investigate the evolution of meiosis proteins in Arabidopsis arenosa, some of which were previously implicated in adaptation to polyploidy, and in a diploid, habitat. A striking and unexplained feature of prior results was the large number of amino acid changes in multiple interacting proteins, especially in the relatively young tetraploid. Here, we investigate whether selection on meiosis genes is found in other lineages, how the polyploid may have accumulated so many differences, and whether derived variants were selected from standing variation. We use a range-wide sample of 145 resequenced genomes of diploid and tetraploid A. arenosa, with new genome assemblies. We confirmed signals of positive selection in the polyploid and diploid lineages they were previously reported in and find additional meiosis genes with evidence of selection. We show that the polyploid lineage stands out both qualitatively and quantitatively. Compared with diploids, meiosis proteins in the polyploid have more amino acid changes and a higher proportion affecting more strongly conserved sites. We find evidence that in tetraploids, positive selection may have commonly acted on de novo mutations. Several tests provide hints that coevolution, and in some cases, multinucleotide mutations, might contribute to rapid accumulation of changes in meiotic proteins. 相似文献
994.
995.
Kirsten Hastrup 《Ethnos》2013,78(3-4):313-324
996.
Kirsten Hastrup 《Ethnos》2013,78(3-4):287-300
The article concerns the continuity between anthropology and the reality it studies. Discovery and definition merge. This is substantiated by a discussion of ‘events’ and ‘worlds’. While the anthropologist becomes her own informant in the field, in the sense that her experience informs her ethnography, anthropology simultaneously shapes her discoveries. This simultaneity ultimately dissolves the distinction between subject and object, and from this point anthropology may recondition the conditions of science. 相似文献
997.
998.
Radiotherapy is the primary treatment for patients with head and neck cancer, which account for roughly 500,000 annual cases worldwide. Dysfunction of the salivary glands and associated conditions like xerostomia and dysphagia are often developed by these patients, greatly diminishing their life quality. Current preventative and palliative care fail to deliver an improvement in the quality of life, thus accentuating the need for regenerative therapies. In this study, a model of label retaining cells (LRCs) in murine salivary glands was developed, in which LRCs demonstrated proliferative potential and possessed markers of putative salivary progenitors. Mice were labeled with 5-Ethynyl-2′-deoxyuridine (EdU) at postnatal day 10 and chased for 8 weeks. Tissue sections from salivary glands obtained at the end of chase demonstrated co-localization between LRCs and the salivary progenitor markers keratin 5 and keratin 14, as well as kit mRNA, indicating that LRCs encompass a heterogeneous population of salivary progenitors. Proliferative potential of LRCs was demonstrated by a sphere assay, in which LRCs were found in primary and secondary spheres and they co-localized with the proliferation marker Ki67 throughout sphere formation. Surprisingly, LRCs were shown to be radio-resistant and evade apoptosis following radiation treatment. The clinical significance of these findings lie in the potential of this model to study the mechanisms that prevent salivary progenitors from maintaining homeostasis upon exposure to radiation, which will in turn facilitate the development of regenerative therapies for salivary gland dysfunction. 相似文献
999.
1000.
Katarzyna Ewa Lewińska Anthony R. Ives Clay J. Morrow Natalia Rogova He Yin Paul R. Elsen Kirsten de Beurs Patrick Hostert Volker C. Radeloff 《Global Change Biology》2023,29(16):4620-4637
Grassland ecosystems cover up to 40% of the global land area and provide many ecosystem services directly supporting the livelihoods of over 1 billion people. Monitoring long-term changes in grasslands is crucial for food security, biodiversity conservation, achieving Land Degradation Neutrality goals, and modeling the global carbon budget. Although long-term grassland monitoring using remote sensing is extensive, it is typically based on a single vegetation index and does not account for temporal and spatial autocorrelation, which means that some trends are falsely identified while others are missed. Our goal was to analyze trends in grasslands in Eurasia, the largest continuous grassland ecosystems on Earth. To do so, we calculated Cumulative Endmember Fractions (annual sums of monthly ground cover fractions) derived from MODIS 2002–2020 time series, and applied a new statistical approach PARTS that explicitly accounts for temporal and spatial autocorrelation in trends. We examined trends in green vegetation, non-photosynthetic vegetation, and soil ground cover fractions considering their independent change trajectories and relations among fractions over time. We derived temporally uncorrelated pixel-based trend maps and statistically tested whether observed trends could be explained by elevation, land cover, SPEI3, climate, country, and their combinations, all while accounting for spatial autocorrelation. We found no statistical evidence for a decrease in vegetation cover in grasslands in Eurasia. Instead, there was a significant map-level increase in non-photosynthetic vegetation across the region and local increases in green vegetation with a concomitant decrease in soil fraction. Independent environmental variables affected trends significantly, but effects varied by region. Overall, our analyses show in a statistically robust manner that Eurasian grasslands have changed considerably over the past two decades. Our approach enhances remote sensing-based monitoring of trends in grasslands so that underlying processes can be discerned. 相似文献