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Justus E Awad D Hohnholt M Schaffran T Edwards K Karlsson G Damian L Gabel D 《Bioconjugate chemistry》2007,18(4):1287-1293
A new class of lipids, containing the closo-dodecaborate cluster, has been synthesized. Two lipids, S-(N, N-(2-dimyristoyloxyethyl)acetamido)thioundecahydro-closo-dodecaborate (2-) (B-6-14) and S-(N, N-(2-dipalmitoyloxyethyl)acetamido)thioundecahydro-closo-dodecaborate (2-) (B-6-16) are described. Both of them have a double-tailed lipophilic part and a headgroup carrying two negative charges. Differential scanning calorimetry shows that B-6-14 and B-6-16 bilayers have main phase transition temperatures of 18.8 and 37.9 degrees C, respectively. Above the transition temperature of 18.8 degrees C, B-6-14 can form liposomal vesicles, representing the first boron-containing lipid with this capability. Upon cooling below the transition temperature, stiff bilayers are formed. When incorporated into liposomal formulations with equimolar amounts of distearoyl phosphatidylcholine (DSPC) and cholesterol, stable liposomes are obtained. The zeta-potential measurements indicate that both B-6-14- and B-6-16-containing vesicles are negatively charged, with the most negative potential described of any liposome so far. The liposomes are of high potential value as transporters of boron to tumor cells in treatments based on boron neutron capture therapy (BNCT). Liposomes prepared from B-6-14 were slightly less toxic in V79 Chinese hamster cells (IC50 5.6 mM) than unformulated Na2B12H11SH (IC50 3.9 mM), while liposomes prepared from B-6-16 were not toxic even at 30 mM. 相似文献
43.
Klemen Novak Martin de Luís José Raventós Katarina Čufar 《Trees - Structure and Function》2013,27(4):927-936
Tree-ring widths (RW), earlywood (EW) and latewood (LW) widths, the transition from early to latewood (T) and the occurrence of intra-annual density fluctuations in EW (E-ring) and in LW (L-ring), as well as the presence of resin canals in EW and LW, were analyzed in Aleppo pine (Pinus halepensis Mill.) from three sites in Spain and one in Slovenia to find out if the anatomical characteristics can provide additional seasonal climate–growth information from contrasted environmental conditions. Principal component analysis was applied to elucidate the relationship between the measured parameters and climate. Principal component factor PC1 proved to be related to parameters of EW and the climatic variables of winter-spring; PC2 to parameters of LW and climatic variables of summer–autumn; PC3 to conditions during transitions from humid to dry periods. The three PCs vary between sites and are determined by the climatic conditions during their formation. The study demonstrates that wood anatomical features may provide complementary information to that contained in tree-ring widths. Since such results are obtained on contrasting sites, it is likely that it may be generalized over the wide range of P. halepensis distribution representing a useful proxy for studies on a regional scale. 相似文献
44.
Properties of the P-Type ATPases Encoded by the copAP Operons of Helicobacter pylori and Helicobacter felis 下载免费PDF全文
Denis Bayle Sabine Wngler Thomas Weitzenegger Wolfram Steinhilber Jürgen Volz Michael Przybylski Klaus P. Schfer George Sachs Klaus Melchers 《Journal of bacteriology》1998,180(2):317-329
The cop operons of Helicobacter pylori and Helicobacter felis were cloned by gene library screening. Both operons contain open reading frames for a P-type ion pump (CopA) with homology to Cd2+ and Cu2+ ATPases and a putative ion binding protein (CopP), the latter representing a CopZ homolog of the copYZAB operon of Enterococcus hirae. The predicted CopA ATPases contained an N-terminal GMXCXXC ion binding motif and a membrane-associated CPC sequence. A synthetic N-terminal peptide of the H. pylori CopA ATPase bound to Cu2+ specifically, and gene disruption mutagenesis of CopA resulted in an enhanced growth sensitivity of H. pylori to Cu2+ but not to other divalent cations. As determined experimentally, H. pylori CopA contains four pairs of transmembrane segments (H1 to H8), with the ATP binding and phosphorylation domains lying between H6 and H7, as found for another putative transition metal pump of H. pylori (K. Melchers, T. Weitzenegger, A. Buhmann, W. Steinhilber, G. Sachs, and K. P. Schäfer, J. Biol. Chem. 271:446–457, 1996). The corresponding transmembrane segments of the H. felis CopA pump were identified by hydrophobicity analysis and via sequence similarity. To define functional domains, similarly oriented regions of the two enzymes were examined for sequence identity. Regions with high degrees of identity included the N-terminal Cu2+ binding domain, the regions of ATP binding and phosphorylation in the energy transduction domain, and a transport domain consisting of the last six transmembrane segments with conserved cysteines in H4, H6, and H7. The data suggest that H. pylori and H. felis employ conserved mechanisms of ATPase-dependent copper resistance. 相似文献
45.
Virus-induced gene silencing-based functional characterization of genes associated with powdery mildew resistance in barley 总被引:18,自引:3,他引:18 下载免费PDF全文
46.
Iva Bozic Katarina Tesovic Danijela Laketa Marija Adzic Marija Jakovljevic Ivana Bjelobaba Danijela Savic Nadezda Nedeljkovic Sanja Pekovic Irena Lavrnja 《Neurochemical research》2018,43(5):1020-1034
Kv1.3 is a voltage gated potassium channel that has been implicated in pathophysiology of multiple sclerosis (MS). In the present study we investigated temporal and cellular expression pattern of this channel in the lumbar part of spinal cords of animals with experimental autoimmune encephalomyelitis (EAE), animal model of MS. EAE was actively induced in female Dark Agouti rats. Expression of Kv1.3 was analyzed at different time points of disease progression, at the onset, peak and end of EAE. We here show that Kv1.3 increased by several folds at the peak of EAE at both gene and protein level. Double immunofluorescence analyses demonstrated localization of Kv1.3 on activated microglia, macrophages, and reactive astrocytes around inflammatory lesions. In vitro experiments showed that pharmacological block of Kv1.3 in activated astrocytes suppresses the expression of proinflammatory mediators, suggesting a role of this channel in inflammation. Our results support the hypothesis that Kv1.3 may be a therapeutic target of interest for MS and add astrocytes to the list of cells whose activation would be suppressed by inhibiting Kv1.3 in inflammatory conditions. 相似文献
47.
Damjanovic Katarina Blackall Linda L. Menéndez Patricia van Oppen Madeleine J. H. 《Coral reefs (Online)》2020,39(1):189-202
Coral Reefs - Corals live in a symbiotic relationship with various microorganisms including bacteria, some of which are essential for host health and survival. Bacterial assemblages are typically... 相似文献
48.
Vrazić H Sikić J Lucijanić T Milosević M Borić K Udovicić M Cmrecnjak J Heim I Gostović MJ Bergovec M 《Collegium antropologicum》2012,36(Z1):229-233
The aim of this paper was to investigate the prevalence of smoking using selected anthropometric variables in a sample of hospitalized coronary heart disease (CHD) patients in Croatia (N = 1,298). A total of 444 subjects (34.6%) were non-smokers, 548 (42.6%) were smokers and 293 (22.8%) were ex-smokers. Men, on average, smoked more cigarettes per day than women (22.62 vs. 19.84 cigarettes, p < 0.001) and they also had bigger index "pack-years" than women (36.96 vs. 33.91, p = 0.024). Men were more often smokers and ex-smokers than women (47.4% vs. 30.8% for smokers and 25.0% vs. 22.8% for ex-smokers, p < 0.001). In this study a high prevalence of smoking was found among CHD patients in Croatia. Unless it is decreased, it can be expected that CHD patients in Croatia will continue to experience adverse effects more often than other CHD patients in the rest of Europe. 相似文献
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