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41.
Capsule Skylarks breeding in Ireland prefer extensive grassland habitats and almost completely avoid tillage habitats.Aims To describe the distribution and habitat use of breeding Skylarks in Ireland, particularly in lowland agricultural habitats, and to use this information to inform conservation measures for this species.Methods Countryside Bird Survey (CBS) and Farmland Bird Project (FBP) data were examined to determine large-scale (national) distribution and habitat selection, in addition to smaller-scale (farm- and field-level) habitat use. The CBS is a national breeding bird monitoring scheme involving 397 1-km squares. The FBP collected detailed bird and habitat data from 122 farms.Results CBS and FBP data both showed significant regional differences in breeding Skylark densities, with the highest relative abundances in the northwest and west. Dry grassland/grass moor habitats supported the highest densities of breeding Skylarks in the CBS, which were significantly higher than in improved grassland or tillage. At the farm-level, Skylark numbers were positively related to wetland habitats but negatively associated with trees in field boundaries, dense ground vegetation and overall density of farm boundaries. At the field-scale, larger fields and unimproved grasslands were preferred.Conclusion Agri-environment measures tailored to region-specific requirements and to the relatively local habitat preferences of target species are required if population declines of species of conservation concern, including Skylarks, are to be reversed. 相似文献
42.
Andrew J. Muinonen-Martin Olivia Susanto Qifeng Zhang Elizabeth Smethurst William J. Faller Douwe M. Veltman Gabriela Kalna Colin Lindsay Dorothy C. Bennett Owen J. Sansom Robert Herd Robert Jones Laura M. Machesky Michael J. O. Wakelam David A. Knecht Robert H. Insall 《PLoS biology》2014,12(10)
The high mortality of melanoma is caused by rapid spread of cancer cells, which occurs unusually early in tumour evolution. Unlike most solid tumours, thickness rather than cytological markers or differentiation is the best guide to metastatic potential. Multiple stimuli that drive melanoma cell migration have been described, but it is not clear which are responsible for invasion, nor if chemotactic gradients exist in real tumours. In a chamber-based assay for melanoma dispersal, we find that cells migrate efficiently away from one another, even in initially homogeneous medium. This dispersal is driven by positive chemotaxis rather than chemorepulsion or contact inhibition. The principal chemoattractant, unexpectedly active across all tumour stages, is the lipid agonist lysophosphatidic acid (LPA) acting through the LPA receptor LPAR1. LPA induces chemotaxis of remarkable accuracy, and is both necessary and sufficient for chemotaxis and invasion in 2-D and 3-D assays. Growth factors, often described as tumour attractants, cause negligible chemotaxis themselves, but potentiate chemotaxis to LPA. Cells rapidly break down LPA present at substantial levels in culture medium and normal skin to generate outward-facing gradients. We measure LPA gradients across the margins of melanomas in vivo, confirming the physiological importance of our results. We conclude that LPA chemotaxis provides a strong drive for melanoma cells to invade outwards. Cells create their own gradients by acting as a sink, breaking down locally present LPA, and thus forming a gradient that is low in the tumour and high in the surrounding areas. The key step is not acquisition of sensitivity to the chemoattractant, but rather the tumour growing to break down enough LPA to form a gradient. Thus the stimulus that drives cell dispersal is not the presence of LPA itself, but the self-generated, outward-directed gradient. 相似文献
43.
Rojas-Aguirre Y Yépez-Mulia L Castillo I López-Vallejo F Soria-Arteche O Hernández-Campos A Castillo R Hernández-Luis F 《Bioorganic & medicinal chemistry》2011,19(2):789-797
The purpose of this work is to study the molecular association that occurs between 2-hydroxypropyl-β-cyclodextrin (HPβCD) and 6-chloro-5-(1-naphthyloxy)-2-(trifluoromethyl)-1H-benzimidazole (RCB20), an antiparasitic compound recently found by our research group, with poor aqueous solubility. The complex stability constant and stoichiometric ratio determined by phase-solubility diagram and Job's plot provided evidence that HPβCD enhanced water solubility of RCB20 through inclusion complex formation. Two-dimensional 1H NMR spectroscopy is used to study the molecular arrangement of inclusion complex in solution. These results are further supported using molecular modeling studies. In the solid state, the complexation is confirmed by differential scanning calorimetry, powder X-ray diffraction, and scanning electron microscopy. Finally, RCB20/HPβCD complex has better activity than RCB20 against the adult and muscle larvae phase of Trichinella spiralis. 相似文献
44.
Fischer JJ Dalhoff C Schrey AK Graebner OY Michaelis S Andrich K Glinski M Kroll F Sefkow M Dreger M Koester H 《Journal of Proteomics》2011,75(1):160-168
Capture Compound Mass Spectrometry (CCMS) is a platform technology for the functional isolation of subproteomes. Here we report the synthesis of two new kinase Capture Compounds (CCs) based on the tyrosine-kinase specific inhibitors dasatinib and imatinib and compare their interaction profiles to that of our previously reported staurosporine-CCs. CCs are tri-functional molecules: they comprise a sorting function (e.g. the small molecule or drug of interest) which interacts with target proteins, a photo-activatable reactivity function to covalently trap the interacting proteins, and a sorting function to isolate the CC-protein conjugates from complex biological samples for protein identification by liquid chromatography/mass spectrometry (LC-MS/MS). We present data of CCMS experiments from human HepG2 cells and compare the profiles of the kinases isolated with dasatinib, imatinib and staurosporine CC, respectively. Dasatinib and imatinib have a more selective kinase binding profile than staurosporine. Moreover, the new CCs allow isolation and identification of additional kinases, complementing the staurosporine CC. The family of kinase CCs will be a valuable tool for the proteomic profiling of this important protein class. Besides sets of expected kinases we identified additional specific interactors; these off-targets may be of relevance in the view of the pharmacological profile of dasatinib and imatinib. 相似文献
45.
Prokaryotes in the WAIS Divide ice core reflect source and transport changes between Last Glacial Maximum and the early Holocene 下载免费PDF全文
Pamela A. Santibáñez Olivia J. Maselli Mark C. Greenwood Mackenzie M. Grieman Eric S. Saltzman Joseph R. McConnell John C. Priscu 《Global Change Biology》2018,24(5):2182-2197
We present the first long‐term, highly resolved prokaryotic cell concentration record obtained from a polar ice core. This record, obtained from the West Antarctic Ice Sheet (WAIS) Divide (WD) ice core, spanned from the Last Glacial Maximum (LGM) to the early Holocene (EH) and showed distinct fluctuations in prokaryotic cell concentration coincident with major climatic states. The time series also revealed a ~1,500‐year periodicity with greater amplitude during the Last Deglaciation (LDG). Higher prokaryotic cell concentration and lower variability occurred during the LGM and EH than during the LDG. A sevenfold decrease in prokaryotic cell concentration coincided with the LGM/LDG transition and the global 19 ka meltwater pulse. Statistical models revealed significant relationships between the prokaryotic cell record and tracers of both marine (sea‐salt sodium [ssNa]) and burning emissions (black carbon [BC]). Collectively, these models, together with visual observations and methanosulfidic acid (MSA) measurements, indicated that the temporal variability in concentration of airborne prokaryotic cells reflected changes in marine/sea‐ice regional environments of the WAIS. Our data revealed that variations in source and transport were the most likely processes producing the significant temporal variations in WD prokaryotic cell concentrations. This record provided strong evidence that airborne prokaryotic cell deposition differed during the LGM, LDG, and EH, and that these changes in cell densities could be explained by different environmental conditions during each of these climatic periods. Our observations provide the first ice‐core time series evidence for a prokaryotic response to long‐term climatic and environmental processes. 相似文献
46.
Jiang W Allan G Chen X Fiordeliso JJ Linton O Tannenbaum P Xu J Zhu P Gunnet J Demarest K Lundeen S Sui Z 《Steroids》2006,71(11-12):949-954
A novel series of steroidal compounds were designed and synthesized with various phosphorus-containing groups on the 17beta-side chain as progesterone receptor antagonists. The structure-activity relationships of these compounds are discussed. Selected compounds were tested in an rat progesterone-sensitive assay. Some of these compounds are more potent than mifepristone, with a better selectivity profile in differentiating progesterone receptor from glucocorticoid receptor. 相似文献
47.
Isabella V. Miller Graca Raposo Ulrich Welsch Olivia Prazeres da Costa Uwe Thiel Maria Lebar Martina Maurer Hans‐Ulrich Bender Irene von Luettichau Günther H. S. Richter Stefan Burdach Thomas G. P. Grunewald 《Biology of the cell / under the auspices of the European Cell Biology Organization》2013,105(7):289-303
48.
49.
High variability in the MHC class II DA beta chain of the brushtail possum (<Emphasis Type="Italic">Trichosurus vulpecula</Emphasis>) 总被引:1,自引:0,他引:1
The diversity of class II major histocompatibility complex (MHC) loci was investigated in the brushtail possum, an important
marsupial pest species in New Zealand. Immunocontraception, a form of fertility control that generates an autoimmune response,
is being developed as a population control method for the possum. Because the immune response is partly under genetic control,
an understanding of immunogenetics in possum will be crucial to the development of immunocontraceptive vaccines. MHC molecules
are critical in the vertebrate immune response. Class II MHC molecules bind and present exogenously derived peptides to T
lymphocytes and may be important in the presentation of immunocontraceptives. We used polymerase chain reaction primers designed
to amplify the peptide binding region of possum class II MHC genes to isolate sequences from 49 animals. We have previously
described 19 novel alleles from the DAB locus in the possum (Holland et al., Immunogenetics 60:449–460, 2008). Here, we report on another 11 novel alleles isolated from possum DAB, making this the most diverse marsupial locus described so far. This high level of diversity indicates that DAB is an important MHC locus in the possum and will need to be taken into account in the design of immunocontraceptive vaccines. 相似文献
50.
Bhandari V Kulshrestha A Deep DK Stark O Prajapati VK Ramesh V Sundar S Schonian G Dujardin JC Salotra P 《PLoS neglected tropical diseases》2012,6(5):e1657