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991.
992.
Jana Vokurková Tereza Petrusková Radka Reifová Alexandra Kozman Libor Mo?kovsky Silke Kipper Michael Weiss Ji?í Reif Pawe? T. Dolata Adam Petrusek 《PloS one》2013,8(4)
Bird song plays an important role in the establishment and maintenance of prezygotic reproductive barriers. When two closely related species come into secondary contact, song convergence caused by acquisition of heterospecific songs into the birds’ repertoires is often observed. The proximate mechanisms responsible for such mixed singing, and its effect on the speciation process, are poorly understood. We used a combination of genetic and bioacoustic analyses to test whether mixed singing observed in the secondary contact zone of two passerine birds, the Thrush Nightingale (Luscinia luscinia) and the Common Nightingale (L. megarhynchos), is caused by introgressive hybridization. We analysed song recordings of both species from allopatric and sympatric populations together with genotype data from one mitochondrial and seven nuclear loci. Semi-automated comparisons of our recordings with an extensive catalogue of Common Nightingale song types confirmed that most of the analysed sympatric Thrush Nightingale males were ‘mixed singers’ that use heterospecific song types in their repertoires. None of these ‘mixed singers’ possessed any alleles introgressed from the Common Nightingale, suggesting that they were not backcross hybrids. We also analysed songs of five individuals with intermediate phenotype, which were identified as F1 hybrids between the Thrush Nightingale female and the Common Nightingale male by genetic analysis. Songs of three of these hybrids corresponded to the paternal species (Common Nightingale) but the remaining two sung a mixed song. Our results suggest that although hybridization might increase the tendency for learning songs from both parental species, interspecific cultural transmission is the major proximate mechanism explaining the occurrence of mixed singers among the sympatric Thrush Nightingales. We also provide evidence that mixed singing does not substantially increase the rate of interspecific hybridization and discuss the possible adaptive value of this phenomenon in nightingales. 相似文献
993.
Br. Błocki 《Plant Systematics and Evolution》1884,34(7):249-251
Ohne Zusammenfassung 相似文献
994.
Pawe
K. Kunicki 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2001,755(1-2)
A HPLC–UV determination of loratadine in human plasma is presented. After simple liquid–liquid extraction with 2-methylbutane–hexane (2:1) and evaporation of organic phase the compounds were re-dissolved in 0.01 M HCl, evaporated again and finally separated on a Supelcosil LC-18-DB column. The analyses were done at ambient temperature under isocratic conditions using the mobile phase: CH3CN–water–0.5 M KH2PO4–H3PO4 (440:480:80:1, v/v). UV detection was performed at 200 nm with a limit of quantification of 0.5 ng/ml. The precision was found to be satisfactory over the whole range tested (0.5–50 ng/ml) with relative standard deviations of 2.3–6.3 and 5.2–14.1% for intra- and inter-assays, respectively. 相似文献
995.
Mikołaj Świerczyński Agata Szymaszkiewicz Jakub Fichna Marta Zielińska 《生物化学与生物物理学报:癌评论》2021,1875(1):188460
Colorectal cancer (CRC) is one of the most common cause of death among neoplasms around the world. The environmental factors, like diet and obesity, are crucial in CRC pathogenesis by creating cancer-favorable microenvironment and hormonal changes. Adiponectin, the adipose tissue-specific hormone, is generally considered to negatively correlate with CRC development. The interleukin 6 (IL-6) is one of the most important pro-inflammatory cytokine connected with CRC, which is strongly inflammation-associated. The opioids are variable group substantially correlated with cancers - the endogenous opioids affect immune system and cell cycle including proliferation and cell death whereas exogenous opioids are leading clinically used analgesics in terminal cancer patients. In this review we discuss the involvement of adiponectin, IL-6 and opioids in CRC pathogenesis, their link with obesity, possible cross-talk and potential novel therapeutic approach in CRC treatment. 相似文献
996.
Przemys?aw Karpowicz Pawe? A. Osmulski Julia Witkowska Emilia Sikorska Ma?gorzata Gi?yńska Agnieszka Belczyk-Ciesielska Maria E. Gaczynska El?bieta Jankowska 《PloS one》2015,10(11)
The proteasome is a giant protease responsible for degradation of the majority of cytosolic proteins. Competitive inhibitors of the proteasome are used against aggressive blood cancers. However, broadening the use of proteasome-targeting drugs requires new mechanistic approaches to the enzyme’s inhibition. In our previous studies we described Tat1 peptide, an allosteric inhibitor of the proteasome derived from a fragment of the basic domain of HIV-Tat1 protein. Here, we attempted to dissect the structural determinants of the proteasome inhibition by Tat1. Single- and multiple- alanine walking scans were performed. Tat1 analogs with stabilized beta-turn conformation at positions 4–5 and 8–9, pointed out by the molecular dynamics modeling and the alanine scan, were synthesized. Structure of Tat1 analogs were analyzed by circular dichroism, Fourier transform infrared and nuclear magnetic resonance spectroscopy studies, supplemented by molecular dynamics simulations. Biological activity tests and structural studies revealed that high flexibility and exposed positive charge are hallmarks of Tat1 peptide. Interestingly, stabilization of a beta-turn at the 8–9 position was necessary to significantly improve the inhibitory potency. 相似文献
997.
998.
Joanna Papierska Bartłomiej S. Witkowski Anastasiya Derkachova Krzysztof P. Korona Johannes Binder Krzysztof Gałkowski Łukasz Wachnicki Marek Godlewski Tomasz Dietl Jan Suffczyński 《Plasmonics (Norwell, Mass.)》2013,8(2):913-919
A simple fabrication method of silver (Ag) nanoislands on ZnO films is presented. Continuous wave and time-resolved photoluminescence and transmission are employed to investigate modifications of visible and UV emissions of ZnO brought about by coupling to localized surface plasmons residing on Ag nanoislands. The size of the nanoislands, determining their absorption and scattering efficiencies, is found to be an important factor governing plasmonic modification of optical response of ZnO films. The presence of the Ag nanoislands of appropriate dimensions causes a strong (threefold) increase in emission intensity and up to 1.5 times faster recombination. The experimental results are successfully described by model calculations within the Mie theory. 相似文献
999.
Katarzyna Szczepańska Tadeusz Karcz Magdalena Kotańska Agata Siwek Kamil J. Kuder Gniewomir Latacz Szczepan Mogilski Stefanie Hagenow Annamaria Lubelska Michał Sobolewski Holger Stark Katarzyna Kieć-Kononowicz 《Bioorganic & medicinal chemistry》2018,26(23-24):6056-6066
As a continuation of our search for novel histamine H3 receptor ligands, a series of new acetyl and propionyl phenoxyalkylamine derivatives (2–25) was synthesized. Compounds with three to four carbon atoms alkyl chain spacer, composed of six various 4N-substituted piperazine moieties were evaluated for their binding properties at human histamine H3 receptors (hH3R). In vitro test results proved the 4-pyridylpiperazine moiety as crucial element for high hH3R affinity (hH3R Ki?=?5.2–115?nM). Moreover introduction of carbonyl group containing residues in the lipophilic part of molecules instead of branched alkyl substituents resulted in increased affinity in correlation to previously described series, whereas propionyl derivatives showed slightly higher affinities than those of acetyl (16 and 22vs.4 and 10; hH3R Ki?=?5.2 and 15.4?nM vs. 10.2 and 115?nM, respectively). These findings were confirmed by molecular modelling studies, demonstrating multiple ligand-receptor interactions. Furthermore, pharmacological in vivo test results of compound 4 clearly indicate that it may affect the amount of calories consumed, thus act as an anorectic compound. Likewise, its protective action against hyperglycemia and the development of overweight has been shown. In order to estimate drug-likeness of compound 4, in silico and experimental evaluation of metabolic stability in human liver microsomes was performed. 相似文献
1000.
Agnieszka Boś-Liedke Magdalena Walawender Anna Woźniak Dorota Flak Jacek Gapiński Stefan Jurga Małgorzata Kucińska Adam Plewiński Marek Murias Marwa Elewa Lisa Lampp Peter Imming Krzysztof Tadyszak 《Cell biochemistry and biophysics》2018,76(1-2):19-28
Oxygenation is one of the most important physiological parameters of biological systems. Low oxygen concentration (hypoxia) is associated with various pathophysiological processes in different organs. Hypoxia is of special importance in tumor therapy, causing poor response to treatment. Triaryl methyl (TAM) derivative radicals are commonly used in electron paramagnetic resonance (EPR) as sensors for quantitative spatial tissue oxygen mapping. They are also known as magnetic resonance imaging (MRI) contrast agents and fluorescence imaging compounds. We report the properties of the TAM radical tris(2,3,5,6-tetrachloro-4-carboxy-phenyl)methyl, (PTMTC), a potential multimodal (EPR/fluorescence) marker. PTMTC was spectrally analyzed using EPR and characterized by estimation of its sensitivity to the oxygen in liquid environment suitable for intravenous injection (1?mM PBS, pH?=?7.4). Further, fluorescent emission of the radical was measured using the same solvent and its quantum yield was estimated. An in vitro cytotoxicity examination was conducted in two cancer cell lines, HT-29 (colorectal adenocarcinoma) and FaDu (squamous cell carcinoma) and followed by uptake studies. The stability of the radical in different solutions (PBS pH?=?7.4, cell media used for HT-29 and FaDu cells culturing and cytotoxicity procedure, full rat blood and blood plasma) was determined. Finally, a primary toxicity test of PTMTC was carried out in mice. Results of spectral studies confirmed the multimodal properties of PTMTC. PTMTC was demonstrated to be not absorbed by cancer cells and did not interfere with luciferin-luciferase based assays. Also in vitro and in vivo tests showed that it was non-toxic and can be freely administrated till doses of 250?mg/kg BW via both i.v. and i.p. injections. This work illustrated that PTMTC is a perfect candidate for multimodal (EPR/fluorescence) contrast agent in preclinical studies. 相似文献