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151.
Chia YC Chen KS Chang YL Teng CM Wu YC 《Bioorganic & medicinal chemistry letters》1999,9(23):3295-3300
Seventeen aporphines were tested for antiplatelet activity. L-(+)-hemovine HCl and 7-hydroxydehydrothalicsimidine strongly inhibited platelet aggregation induced by adenosine 5'-diphosphate (ADP), arachidonic acid (AA), collagen, and platelet-activating factor (PAF). The latter showed the strongest antiplatelet activity with an IC50 of 70.4 microM against AA-induced platelet aggregation. 相似文献
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153.
Chia TW Nguyen VT McMeekin T Fegan N Dykes GA 《Applied and environmental microbiology》2011,77(11):3757-3764
Bacterial attachment onto materials has been suggested to be stochastic by some authors but nonstochastic and based on surface properties by others. We investigated this by attaching pairwise combinations of two Salmonella enterica serovar Sofia (S. Sofia) strains (with different physicochemical and attachment properties) with one strain each of S. enterica serovar Typhimurium, S. enterica serovar Infantis, or S. enterica serovar Virchow (all with similar physicochemical and attachment abilities) in ratios of 0.428, 1, and 2.333 onto glass, stainless steel, Teflon, and polysulfone. Attached bacterial cells were recovered and counted. If the ratio of attached cells of each Salmonella serovar pair recovered was the same as the initial inoculum ratio, the attachment process was deemed stochastic. Experimental outcomes from the study were compared to those predicted by the extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory. Significant differences (P < 0.05) between the initial and the attached ratios for serovar pairs containing S. Sofia S1296a for all different ratios were apparent for all materials. For S. Sofia S1635-containing pairs, 7 out of 12 combinations of serovar pairs and materials had attachment ratios not significantly different (P > 0.05) from the initial ratio of 0.428. Five out of 12 and 10 out of 12 samples had attachment ratios not significantly different (P > 0.05) from the initial ratios of 1 and 2.333, respectively. These results demonstrate that bacterial attachment to different materials is likely to be nonstochastic only when the key physicochemical properties of the bacteria were significantly different (P < 0.05) from each other. XDLVO theory could successfully predict the attachment of some individual isolates to particular materials but could not be used to predict the likelihood of stochasticity in pairwise attachment experiments. 相似文献
154.
Lipocalin 2 (LCN2) is produced by mammalian hosts to bind bacterial siderophore and sequester free iron as part of an innate immune response, and could also play a role in tissue iron homeostasis, but thus far, little is known about its expression in the CNS. The present study was carried out to study the expression of the lipocalin in the normal rat brain and after neuronal injury induced by kainate (KA). Low levels of LCN2 mRNA and protein expression were detected in most regions of the normal brain except the olfactory bulb, brainstem and cerebellum. KA lesions resulted in damage to the hippocampus, leading to an early increase at three days and a sustained elevation in LCN2 mRNA level of 16-fold, and protein expression at 80-fold in the lesioned tissue compared to controls at 2 weeks post-KA injection. The sustained elevation in mRNA expression was not detected among other lipocalins surveyed using real-time RT-PCR - apoD, PGDS, Rbp4 and LCN5. Single and double immunostaining confirmed that LCN2 is present in astrocytes in the olfactory bulb, brainstem and cerebellum of the normal brain, and reactive astrocytes in the KA-lesioned hippocampus. In conclusion, the present study showed LCN2 to be present in select brain regions, and is upregulated in astrocytes after neuronal injury induced by kainate. We postulate that, as in the periphery, LCN2 may have a role in iron transport or trafficking in the CNS. 相似文献
155.
Aims: To investigate the relative role of the red dry and rough (rdar) and brown dry and rough (bdar) morphotypes on hydrophobicity and ability to attach to abiotic surfaces of poultry‐associated Salmonella strains with a focus on S. Sofia. Methods and Results: Cellulose synthase gene null mutants were constructed in five Salmonella strains converting them from rdar to bdar morphotypes. One S. Sofia null mutant displayed reduced hydrophobicity and attachment to Teflon® relative to its parent strain. The S. Virchow and S. Infantis null mutants attached less well to glass relative to their parent strains. Conclusions: The rdar or bdar morphotype may influence S. Sofia persistence but did not explain why bdar strains predominate in this serotype. Significance and Impact of the Study: This work provides some insight into why some Salmonella strains survive in poultry environments and may ultimately contribute to their control. 相似文献
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157.
Brown CJ Lim JJ Leonard T Lim HC Chia CS Verma CS Lane DP 《Journal of molecular biology》2011,405(3):736-753
Eukaryotic initiation factor (eIF)4E is overexpressed in many types of cancer such as breast, head and neck, and lung. A consequence of increased levels of eIF4E is the preferential translation of pro-tumorigenic proteins such as c-Myc, cyclin D1, and vascular endothelial growth factor. Inhibition of eIF4E is therefore a potential therapeutic target for human cancers. A novel peptide based on the eIF4E-binding peptide eIF4G1, where the α-helix was stabilized by the inclusion of α-helix inducers as shown by CD measurements, was synthesized. The helically stabilized peptide binds with an apparent Kd of 9.43 ± 2.57 nM, which is ∼ 15.7-fold more potent than the template peptide from which it is designed. The helically stabilized peptide showed significant biological activity at a concentration of 400 μM, unlike the naturally occurring eIFG1 peptide when measured in cell-based cap-dependent translational reporter and WST-1 (4-[3-(4-iodophenyl)-2-(4-nitrophenyl)-2H-5-tetrazolio]-1,3-benzene disulfonate) assays. Fusion of the template peptide and the stabilized peptide to the cell-penetrating peptide TAT produced more active but equally potent inhibitors of cap-dependent translation in cell lines. They also equally disrupted cell metabolism as measured in a WST-1 assay. Propidium iodide staining revealed that the TAT-fused, helically stabilized peptide caused more cell death than the TAT-fused eIF4G1 template peptide with substantial decreases in the G1 and G2 cell populations. Annexin-staining experiments also indicated that the TAT-fused eIF4G1 derivative peptides caused cell death by apoptosis. The results presented should offer further insight into peptidomimetics development for eIF4E. 相似文献
158.
Impact of the functional status of saeRS on in vivo phenotypes of Staphylococcus aureus sarA mutants
Agnieszka K. Zielinska Danielle N. Atwood Allister J. Loughran Linda M. Griffin K. Alice Matthews Allison M. Anthony Horace J. Spencer Robert A. Skinner Ginell R. Post Chia Y. Lee Mark S. Smeltzer 《Molecular microbiology》2014,92(6):1299-1312
We investigated the in vivo relevance of the impact of sarA and saeRS on protease production using derivatives of the USA300 strain LAC. The results confirmed that mutation of saeRS or sarA reduces virulence in a bacteremia model to a comparable degree. However, while eliminating protease production restored virulence in the sarA mutant, it had little impact in the saeRS mutant. Additionally, constitutive activation of saeRS (saeRSC) enhanced the virulence of LAC and largely restored virulence in the isogenic sarA mutant. Based on these results, together with our analysis of the representative virulence factors alpha toxin, protein A (Spa), and extracellular nucleases, we propose a model in which the attenuation of saeRS mutants is defined primarily by decreased production of such factors, while constitutive activation of saeRS increases virulence, and reverses the attenuation of sarA mutants, because it results in both increased production and decreased protease‐mediated degradation of these same factors. This regulatory balance was also apparent in a murine model of catheter‐associated infection, with the results suggesting that the impact of saeRS on nuclease production plays an important role during the early stages of these infections that is partially offset by increased protease production in sarA mutants. 相似文献
159.
Benign Solutions and Innovative Sequential Annealing Processes for High Performance Cu2ZnSn(Se,S)4 Photovoltaics 下载免费PDF全文
Solution‐based earth‐abundant Cu2ZnSn(Se,S)4 (CZTSSe) is proven to be a promising tool for thin‐film photovoltaic fabrication. Combining fully dissolved copper (Cu) and zinc/tin (Zn/Sn) hydrazinium constituents in an ethanolamine (EA) and dimethylsulfoxide (DMSO) solution mixture forms the CZTS precursor. All solutes in the precursor solution are intermixed on the molecular scale with excellent homogeneity. Sequential annealing steps under chalcogen vapor allow for enhanced grain growth while preventing the back contact from forming an excessively thick Mo(S,Se)2 layer. The resulting devices achieve power conversion efficiencies of 7.5% under 1 sun conditions. 相似文献
160.