3T3 and VH10 cells were subjected to oxidative damage by hydroxyl radicals generated from Cu(II) ions and ascorbate. The presence of reactive oxygen and nitrogen species in cells was determined using fluorescent dyes. MitoQ—a mitochondrially targeted antioxidant—was examined to prevent cell death and was compared with trolox as a reference standard serving as an antioxidant. MitoQ at lower concentrations (up to 500 nM) prevented damage of mitochondria and thereby increased viability of cells. However, at higher concentrations (over 500 nM) MitoQ decreased the viability of both strains of cells. The last observation indicates that the application of MitoQ should be evaluated also from the point of its cell-destructive potential. 相似文献
Liquid-crystalline perylene-3,4,9,10-tetra-(n-hexylester) forms characteristic dendritic or flower-like structures at room temperature when it is deposited on a hydrophilic glass substrate using the zone-casting technique. It was found that such unique structures were not possible to be created simply by recrystallisation of this dye from a liquid-crystalline columnar phase. On the basis of the observations using a confocal microscope and the study of wide angle X-ray scattering (WAXS) as well as the analysis of the absorption and fluorescence spectra, some conclusions, concerning the molecular organisation in the dendritic structure, are drawn. Based on the research, one can assume that the dendrites are formed by columnar molecular aggregates with the column axes parallel to the substrate. Such an organisation of the molecules can be interesting from the point of view of organic electronics. 相似文献
A spacer-equipped tetrasaccharide, p-aminocyclohexylethyl alpha-l-Colp-(1-->2)-beta-d-Galp-(1-->3)-[alpha-l-Colp-(1-->4)]-beta-D-GlcpNAc, containing a 4,6-cyclic phosphate in the galactose residue, has been synthesised. The structure corresponds to a part of the repeating unit of the capsular (and lipo-) polysaccharide of the endemic bacteria Vibrio cholerae type O139 synonym Bengal. The synthetic strategy allows continuous syntheses of the complete O139 hexasaccharide repeating unit as well as of the structurally related repeating unit of serotype O22. Starting from ethyl 2-azido-4,6-O-benzylidene-2-deoxy-1-thio-beta-D-glucopyranoside, a thioglycoside tetrasaccharide donor block was constructed through two orthogonal glycosylations with glycosyl bromide donors. First, a properly protected galactose moiety was introduced using silver triflate as promoter and subsequently the two colitose residues, carrying electron-withdrawing protecting groups for stability reasons, under halide-assisted conditions. The tetrasaccharide block was then linked to the spacer in a NIS-TMSOTf-promoted coupling. Transformation of the azido group into an acetamido group using H2S followed by removal of temporary protecting acetyl groups gave a 4',6'-diol, which was next phosphorylated with methyl dichlorophosphate and deprotected to yield the 4,6-cyclic phosphate tetrasaccharide target structure. 相似文献
For the design of a biohybrid structure as a ligand‐tailored drug delivery system (DDS), it is highly sophisticated to fabricate a DDS based on smoothly controllable conjugation steps. This article reports on the synthesis and the characterization of biohybrid conjugates based on noncovalent conjugation between a multivalent biotinylated and PEGylated poly(amido amine) (PAMAM) dendrimer and a tetrameric streptavidin‐small protein binding scaffold. This protein binding scaffold (SA‐ABDwt) possesses nM affinity toward human serum albumin (HSA). Thus, well‐defined biohybrid structures, finalized by binding of one or two HSA molecules, are available at each conjugation step in a controlled molar ratio. Overall, these biohybrid assemblies can be used for (i) a controlled modification of dendrimers with the HSA molecules to increase their blood‐circulation half‐life and passive accumulation in tumor; (ii) rendering dendrimers a specific affinity to various ligands based on mutated ABD domain, thus replacing tedious dendrimer–antibody covalent coupling and purification procedures.
The stable isotopic analyses of molecular oxygen dissolved in water (delta18O(DO)) and dissolved inorganic carbon (delta13C(DIC)), supplemented with basic chemical measurements, have been carried out on a diurnal basis to better understand the dynamics of photosynthesis and respiration in freshwater systems. Our observations have been carried out in a lowland dam reservoir, the Sulejow Lake (central Poland), during the summer cyanobacterial bloom. All data obtained, isotopic, hydrochemical, and biological, show a high mutual consistency. Namely, the lowest delta18O(DO) values, obtained at 10:00 and 14:00 (16.0 and 15.5 per thousand, respectively), correspond to the highest amount of cyanobacterial cells observed (66 and 63 mg dm(-3), respectively), whereas the minimum delta13C(DIC) (-10.6 per thousand) obtained at 22:00 corresponds to the maximum content of organic matter (110 mg dm(-3)). This evidence suggests that isotopic assays of delta18O(DO) and delta13C(DIC) are a reliable tool for the quantitative study of biochemical processes in freshwater systems. 相似文献
One of the effective treatments for diabetes is to reduce and delay the absorption of glucose by inhibition of α-amylase and α-glucosidase in the digestive tract. Currently, there is a great interest in natural inhibitors from various part of plants. In the present study, the phenolic compounds composition of V. opulus bark and flower, and their inhibitory effects on in vitro potato starch digestion as well as on α-amylase and α-glucosidase, have been studied. Bark and flower phenolic extracts reduced the amount of glucose released from potato starch during tree-stage simulated digestion, with IC50 value equal to 87.77 µg/mL and 148.87 µg/mL, respectively. Phenolic bark extract showed 34.9% and 38.4% more potent inhibitory activity against α-amylase and α-glucosidase, respectively, but the activity of plant extracts was lower than that of acarbose. Chlorogenic acid (27.26% of total phenolics) and (+)-catechin (30.48% of total phenolics) were the most prominent phenolics in the flower and bark extracts, respectively. Procyanidins may be responsible for the strongest V. opulus bark inhibitory activity against α-amylase, while (+)-catechin relative to α-glucosidase. This preliminary study provides the basis of further examination of the suitability of V. opulus bark compounds as components of nutraceuticals and functional foods with antidiabetic activity. 相似文献
Despite the fact that phytochemicals of Cornaceae species have long been discussed as possible auxiliary agents in contemporary treatment, the insights on their properties remain relatively scarce. This study focuses on Cornus mas L. (Cornelian cherry), the extracts of which are reported to exert a pleiotropic effect shown in both in vivo and in vitro studies. This study aimed to explore the cytotoxic effect of extracts from fruits of red (Cornus mas L. ‘Podolski’) and yellow (Cornus mas L. ‘Yantarnyi’ and ‘Flava’) Cornelian cherries on two melanoma cell lines (A375 and MeWo). The extracts were characterized in the context of the concentration of bioactive compounds of antioxidative properties. Cytotoxicity was investigated with the use of the following two assays: SRB and MTT. An additional, alternative protocol for the SRB assay was used in this study so as to account for possible bias. Cytotoxicity was assessed as a difference in the whole time series of cell viability, instead of analyzing differences in raw values (often found in the literature). Both extracts from Cornus mas L. induced cytotoxicity in both A375 and MeWo cell lines, although the response of these cells was different. Moreover, based on this study, there is no evidence for claiming a different magnitude of cytotoxicity between these two extracts. 相似文献
