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21.
Like other species of the genus Taxus, European yew trees contain taxanes, including paclitaxel (T) and its precursor 10-deacetylbaccatin III (10-DAB). Taxanes are one of the most effective anticancer drugs. This study was undertaken to describe the levels and patterns of taxane variation in the Sudetian region (SW Poland). Paclitaxel (T) and 10-deacetylbaccatin III (10-DAB) concentrations were analysed in five populations. Needles and twigs were analysed from 60 individuals (30 males and 30 females) in each population. In addition, morphometric measurements were taken in the populations to obtain light intensity coefficients (specific leaf area, SLA). High variability in the taxane contents at both intra and interpopulational levels was found. Nevertheless, females had a significantly higher taxane content compared to males. Because taxanes are carbon-based secondary metabolites, females have higher rate of gas exchange of females compared to males. This was probably an adaptation to greater reproductive effort incurred by females. In this regard, female individuals seem to be better for selecting elite cultivars with a higher taxane production. The relationship between light intensity and taxane content was not significant. Shading, important for optimizing crop production, should not reduce the concentration of taxanes. 相似文献
22.
Cette publication présente les résultats d’une étude de 6.263 spécimens de Xylocopinae récoltés en France métropolitaine (France continentale et Corse) et en Belgique et qui proviennent de récoltes personnelles et de 63 institutions et collections privées. Les Xylocopinae de France sont représentées par 11 espèces du genre Ceratina et 4 espèces du genre Xylocopa. Seules deux de ces espèces sont présentes en Belgique : Xylocopa violacea (L.) et Ceratina cyanea (Kirby). Un nouveau sous-genre pour le genre Ceratina est décrit : Dalyatina n. subg. Il comporte l’espèce méditerranéenne Ceratina parvula Smith présente en France, ainsi que six autres espèces d’Afrique subsaharienne. Pour chaque genre, sous-genre et espèce, les auteurs fournissent une diagnose, une diagnose différentielle, la liste des fleurs visitées, la liste des sites de nidification, la carte de distribution en France métropolitaine, un diagramme phénologique et une clé d’identifi cation des genres, sous-genres et espèces. La systématique, la biogéographie, l’écologie et le sexe ratio des espèces sont présentés et discutés. Les Xylocopinae apparaissent comme très largement polylectiques mais montrent une très nette affinité envers les Lamiaceae, les Asteraceae Cardueae et, pour le genre Xylocopa, envers les Fabaceae. Toutes les espèces présentent une phénologie estivale qui s’étend d’avril à septembre. Le sexe-ratio de la plupart des espèces est biaisé vers les femelles. Aucun mâle de C. parvula, pour 120 femelles, n’a été observé ce qui suggère que, en France du moins, l’espèce pourrait se reproduire par parthénogenèse thélytoque comme c’est le cas de C. dallatorreana Friese. La publication comprend 62 dessins au trait, 18 photos au microscope électronique à balayage, 17 cartes, 14 graphiques de phénologie, une liste de 232 espèces de fleurs visitées par les Xylocopinae, dont 176 observations originales, et 171 références. 相似文献
23.
Sławomir Wąsik Michał Arabski Zuzanna Drulis-Kawa Jerzy Gubernator 《European biophysics journal : EBJ》2013,42(7):549-558
The paper presents experimental investigations of diffusion of antibiotics (ciprofloxacin or ampicillin) into the water phase from mixtures of neutral or negatively charged liposomes, and antibiotic–liposome interactions. Using the laser interferometry technique, the amounts and fluxes of released antibiotics, concentration field evolution, and the velocity of the concentration boundary layer’s “growth” were determined. To avoid the limitations of membranes, a measurement system without the artificial boundary of phases with a free water–solution interface has been proposed. It was found that the diffusion of anionic and neutral liposomes into the water phase was insignificant and mainly the diffusion of antibiotics was measured. Differences in the diffusion kinetics of ciprofloxacin and ampicillin from liposomal solutions to the water phase were observed. Ampicillin diffused more efficiently than ciprofloxacin regardless of the liposomal solution type. Moreover, the amount of ampicillin and ciprofloxacin released from the anionic liposomal phase was higher than that from the neutral one. Our results confirm that ciprofloxacin at neutral pH shows little tendency to bind neutral liposomes. Additionally, it was also observed that ciprofloxacin disrupts negatively charged liposomes as a final effect of antibiotic–lipid interactions. 相似文献
24.
Patrycja M. Dubielecka Anna Trusz Witold Diakowski Michał Grzybek Anna Chorzalska Bozena Jaźwiec 《Molecular membrane biology》2013,30(3):235-243
Understanding drug-membrane and drug-membrane protein interactions would be a crucial step towards understanding the action and biological properties of anthracyclines, as the cell membrane with its integral and peripheral proteins is the first barrier encountered by these drugs. In this paper, we briefly describe mitoxantrone-monolayer and mitoxantrone-bilayer interactions, focusing on the effect of mitoxantrone on the interactions between erythroid or nonerythroid spectrin with phosphatidylethanolamine-enriched mono- and bilayers. We found that mitoxantrone markedly modifies the interaction of erythroid and nonerythroid spectrins with phosphatidylethanolamine/phosphatitydcholine (PE/PC) monolayers. The change in Δπ induced by spectrins is several-fold larger in the presence of 72?nM mitoxantrone than in its absence: spectrin/mitoxantrone complexes induced a strong compression of the monolayer. Spin-labelling experiments showed that spectrin/mitoxantrone complexes caused significant changes in the order parameter measured using a 5′-doxyl stearate probe in the bilayer, but they practically did not affect the mobility of 16′-doxyl stearate. These results indicate close-to-surface interactions/penetrations without significant effect on the mid-region of the hydrophobic core of the bilayer. The obtained apparent equilibrium dissociation constants indicated relatively similar mitoxantrone-phospholipid and mitoxantrone-spectrin (erythroid and nonerythroid) binding affinities. These results might in part, explain the effect of mitoxantrone on spectrin distribution in the living cells. 相似文献
25.
Hugues?GentillonEmail author Ludomir?Stefańczyk Micha??Strzelecki Maria?Respondek-Liberska 《BMC research notes》2016,9(1):496
Background
Magnetic resonance data were collected from a diverse population of gravid women to objectively compare the quality of 1.5-tesla (1.5 T) versus 3-T magnetic resonance imaging of the developing human brain. MaZda and B11 computational-visual cognition tools were used to process 2D images. We proposed a wavelet-based parameter and two novel histogram-based parameters for Fisher texture analysis in three-dimensional space.Results
Wavenhl, focus index, and dispersion index revealed better quality for 3 T. Though both 1.5 and 3 T images were 16-bit DICOM encoded, nearly 16 and 12 usable bits were measured in 3 and 1.5 T images, respectively. The four-bit padding observed in 1.5 T K-space encoding mimics noise by adding illusionistic details, which are not really part of the image. In contrast, zero-bit padding in 3 T provides space for storing more details and increases the likelihood of noise but as well as edges, which in turn are very crucial for differentiation of closely related anatomical structures.Conclusions
Both encoding modes are possible with both units, but higher 3 T resolution is the main difference. It contributes to higher perceived and available dynamic range. Apart from surprisingly larger Fisher coefficient, no significant difference was observed when testing was conducted with down-converted 8-bit BMP images.26.
Negative effects of density on space use of small mammals differ with the phase of the masting‐induced population cycle 下载免费PDF全文
Michał Bogdziewicz Rafał Zwolak Lauren Redosh Leszek Rychlik Elizabeth E. Crone 《Ecology and evolution》2016,6(23):8423-8430
Home range size generally decreases with increasing population density, but testing how this relationship is influenced by other factors (e.g., food availability, kin structure) is a difficult task. We used spatially explicit capture–recapture models to examine how home range size varies with population density in the yellow‐necked mouse (Apodemus flavicollis). The relationship between population density and home range size was studied at two distinct phases of population fluctuations induced by beech (Fagus sylvatica) masting: post‐mast peak in abundance (first summer after mast, n = 2) and subsequent crash (second summer after mast, n = 2). We live‐trapped mice from June to September to avoid the confounding effects of autumn seedfall on home range size. In accordance with general predictions, we found that home range size was negatively associated with population density. However, after controlling for the effect of density, home ranges of mice were larger in post‐mast years than during the crash phase. This indicates a higher spatial overlap among neighbors in post‐mast years. We suggest that the increased spatial overlap is caused by negative density‐dependent dispersal that leads to high relatedness of individuals within population in the peak phase of the cycle. 相似文献
27.
Tadeusz Osadnik Joanna Katarzyna Strzelczyk Rafa? Regu?a Kamil Bujak Martyna Fronczek Ma?gorzata Gonera Marcin Gawlita Jaros?aw Wasilewski Andrzej Lekston Anna Kurek Marek Gierlotka Przemys?aw Trzeciak Micha? Hawranek Zofia Ostrowska Andrzej Wiczkowski Lech Poloński Mariusz G?sior 《PloS one》2016,11(3)
Background
Neointima forming after stent implantation consists of vascular smooth muscle cells (VSMCs) in 90%. Growth factors TGF-β1, PDGFB, EGF, bFGF and VEGF-A play an important role in VSMC proliferation and migration to the tunica intima after arterial wall injury. The aim of this paper was an analysis of functional polymorphisms in genes encoding TGF-β1, PDGFB, EGF, bFGF and VEGF-A in relation to in-stent restenosis (ISR).Materials and Methods
265 patients with a stable coronary artery disease (SCAD) hospitalized in our center in the years 2007–2011 were included in the study. All patients underwent stent implantation at admission to the hospital and had another coronary angiography performed due to recurrence of the ailments or a positive result of the test assessing the coronary flow reserve. Angiographically significant ISR was defined as stenosis >50% in the stented coronary artery segment. The patients were divided into two groups–with angiographically significant ISR (n = 53) and without significant ISR (n = 212). Additionally, the assessment of late lumen loss (LLL) in vessel was performed. EGF rs4444903 polymorphism was genotyped using the PCR-RFLP method whilst rs1800470 (TGFB1), rs2285094 (PDGFB) rs308395 (bFGF) and rs699947 (VEGF-A) were determined using the TaqMan method.Results
Angiographically significant ISR was significantly less frequently observed in the group of patients with the A/A genotype of rs1800470 polymorphism (TGFB1) versus patients with A/G and G/G genotypes. In the multivariable analysis, LLL was significantly lower in patients with the A/A genotype of rs1800470 (TGFB1) versus those with the A/G and G/G genotypes and higher in patients with the A/A genotype of the VEGF-A polymorphism versus the A/C and C/C genotypes. The C/C genotype of rs2285094 (PDGFB) was associated with greater LLL compared to C/T heterozygotes and T/T homozygotes.Conclusions
The polymorphisms rs1800470, rs2285094 and rs6999447 of the TGFB1, PDGFB and VEGF-A genes, respectively, are associated with LLL in patients with SCAD treated by PCI with a metal stent implantation. 相似文献28.
29.
Ancient animal migration: a case study of eyeless,dimorphic Devonian trilobites from Poland 下载免费PDF全文
We report evidence of one of the oldest known animal migratory episodes in the form of queues of the eyeless trilobite Trimerocephalus chopini Kin & B?a?ejowski, from the Late Devonian (Famennian) of central Poland. In addition, there is evidence for two morphs in this population, one with nine segments and the other with ten. We infer that these queues represent mass migratory chains coordinated by chemotaxis, comparable to those observed in modern crustaceans such as spiny lobsters, and further suggest that the two forms, which occur in an approximately 1:1 ratio, may be dimorphs. These ancient arthropods may have migrated periodically to shallow marine areas for mass mating and spawning. The sudden death of the trilobites in the queues may have been caused by excess carbon dioxide and hydrogen sulphide introduced into the bottom water by distal storm disturbance of anoxic sediments. This study demonstrates the potential for further research on the evolution and ecology of aggregative behaviour in marine arthropods. 相似文献
30.
HD2C histone deacetylase and a SWI/SNF chromatin remodelling complex interact and both are involved in mediating the heat stress response in Arabidopsis 下载免费PDF全文