泥鳅多糖清除活性氧和保护DNA链的作用

采用化学发光法和分光光度法在多种化学模拟体系中研究了泥鳅多糖清除活性氧的作用 ,并用化学发光法观察了泥鳅多糖对·OH导致DNA链损伤的抑制作用。结果表明 ,泥鳅多糖能够有效地清除O·-2 、·OH、H2 O2 等活性氧 ,对DNA链具有良好的保护作用     

Determination of phenolic compounds and diterpenes in roots of Salvia miltiorrhiza and Salvia przewalskii by two LC–MS tools: Multi-stage and high resolution tandem mass spectrometry with assessment of antioxidant capacity

Comparative phytochemical analyses of hydroalcoholic (50% EtOH) extracts from roots of S. miltiorrhiza (SM) and S. przewalskii (SP) were performed using two complementary LC–MS systems: the first system HPLC-DAD-MSⁿ an ion trap mass spectrometer and the second system consisted high resolution MS/MS Orbitrap mass spectrometer. The individual compounds were identified using a previously published approach via comparison of the exact molecular masses, mass spectra and retention times to those of standard compounds, online available databases and literature data. Moreover, the determination of antioxidative activities of extracts by DPPH and FRAP methods was carried out. Analysis allowed to identify 39 chemical compounds in extracts from both species. Extract from root of SP differs from SM in the presence of several metabolites such as: przewalskinic acid and their derivatives, przewaquinone C, przewaquinonate A, glycosides of rosmarinic acid, methyltanshinonate, whereas tanshinones, salvianolic acids and lithospermic acids occurred in both species. Moreover, it was shown that hydroalcoholic extract from roots of SM exerted stronger antioxidant properties in a FRAP test (max. 323.92 μM Fe²⁺/L) and in DPPH test (max. 78.64 nM TE) in comparison with SP extract.     

Analysis of Abscisic Acid in the Brains of Rodents and Ruminants

The surface tension (σ) of batter prepared with one or two of the major ingredients of wheat flour, egg and sucrose was measured by the maximum bubble pressure method. The surface tension of the soft- and hard-wheat flour suspension decreased as the solid content of wheat flour was increased, finally reaching 48.2 and 52.7 dyn/cm, respectively. The surface tension of the wheat flour suspension was lower than that of its supernatant, which suggests that the precipitate reduced the surface tension. Gelatinization of the wheat flour suspension lowered its surface tension. The surface tension of the whole egg dispersion decreased markedly to about 53 dyn/cm as the solid concentration was increased from 0 to 1%, and remained almost constant as the concentration was increased further. This tendency was almost the same as that of the egg yolk dispersion. The surface tension of mixtures of two ingredients such as egg and wheat flour, and egg and sucrose was almost equal to that of the ingredient with the lower surface tension at the same concentration as in the mixture.     

Urban bird trends in a rapidly growing tropical city

Long-term studies of urban birds are relatively scarce, especially in Africa. We analysed trends in species richness and bird species occurrence over a 32-year period in Kampala, Uganda, in order to assess changes in the bird community in a period that has shown rapid expansion of the city's human population. Given that species may respond to urbanisation according to their diet, we also analysed bird community trends of species groups defined according to predominant diet. There was an overall decline in species richness that was largely driven by declines in insectivores and granivores. General declines were evident also when the trends in the most common individual species in these two groups were considered. The occurrence of the commonest predator and scavenger species tended to increase over the period considered. Insectivorous species are likely to be especially affected by increasing urbanisation due to air pollution. Predators and scavengers are likely to have benefitted from the inability of municipal waste management to keep pace with growth in the human population, hence providing more potential food resources. Both insectivores and predators/scavengers are therefore good candidates for the development of urban indicators.     

Natural products as modulators of the nuclear receptors and metabolic sensors LXR,FXR and RXR

Nuclear receptors (NRs) represent attractive targets for the treatment of metabolic syndrome-related diseases. In addition, natural products are an interesting pool of potential ligands since they have been refined under evolutionary pressure to interact with proteins or other biological targets.This review aims to briefly summarize current basic knowledge regarding the liver X (LXR) and farnesoid X receptors (FXR) that form permissive heterodimers with retinoid X receptors (RXR). Natural product-based ligands for these receptors are summarized and the potential of LXR, FXR and RXR as targets in precision medicine is discussed.     

Nitric Oxide Production and Perivascular Tyrosine Nitration Following Focal Ischemia in Neonatal Rat

Abstract: Oxygen free radicals and nitric oxide (NO^•) have been proposed to be involved in acute CNS injury produced by cerebral ischemia; however, controversy remains regarding how they cause injury. Because superoxide generation is triggered during reperfusion, the cytotoxic oxidant peroxynitrite could be formed, but it is not known if this occurs. Dot blot and immunohistochemistry studies were performed on the magnitude and time course of tyrosine nitration and inducible NO synthase (NOS2) in the postischemic rat pup brain. Neonatal ischemia was induced by permanent left middle cerebral artery occlusion in association with 1-h occlusion of the left common carotid artery in 7-day-old Wistar pups. Nitrotyrosine (NT) immunoreactivity was evident in the blood vessels close to the cortical infarct at 48–72 h of recovery, and T lymphocytes were involved with this production. NOS2 immunoreactivity was seen in neutrophils in the same vessels and in the parenchyma at 72 h of recirculation. Whereas NT staining decreased with time, NOS2-positive neutrophils could be still detected in arachnoid vessels at 14 days of recirculation. We conclude that perivascular reactions mediated by peroxynitrite are important in the cascade of events that lead to brain oxidative stress in neonatal ischemia. Moreover, NO-related species may serve as a signaling function instead of directly mediating toxicity.     

Taxonomic review of Agraphydrus from Japan (Coleoptera: Hydrophilidae: Acidocerinae)

The Japanese species of the genus Agraphydrus are revised. Five species are recognized, including Agraphydrus ogatai sp. nov. from Honshu, Shikoku and Kyushu. The new species can be distinguished by the coarse ground punctures on the pronotum and elytra, and by the shape of parameres. All species except A. luteilateralis are redescribed. All species are diagnosed, relevant morphological characters are illustrated, distributional records are summarized and an updated key is provided.     

Peroxynitrite Induces Tyrosine Nitration and Modulates Tyrosine Phosphorylation of Synaptic Proteins

Peroxynitrite, the product of the radical-radical reaction between nitric oxide and superoxide anion, is a potent oxidant involved in tissue damage in neurodegenerative disorders. We investigated the modifications induced by peroxynitrite in tyrosine residues of proteins from synaptosomes. Peroxynitrite treatment (> or =50 microM) induced tyrosine nitration and increased tyrosine phosphorylation. Synaptophysin was identified as one of the major nitrated proteins and pp60src kinase as one of the major phosphorylated substrates. Further fractionation of synaptosomes revealed nitrated synaptophysin in the synaptic vesicles, whereas phosphorylated pp60src was enriched in the postsynaptic density fraction. Tyrosine phosphorylation was increased by treatment with 50-500 microM peroxynitrite and decreased by higher concentrations, suggesting a possible activation/inactivation of kinases. Immunocomplex kinase assay proved that peroxynitrite treatment of synaptosomes modulated the pp60src autophosphorylation activity. The addition of bicarbonate (CO2 1.3 mM) produced a moderate enhancing effect on some nitrated proteins but significantly protected the activity of pp60src against peroxynitrite-mediated inhibition so that at 1 mM peroxynitrite, the kinase was still more active than in untreated synaptosomes. The phosphotyrosine phosphatase activity of synaptosomes was inhibited by peroxynitrite (> or =50 microM) but significantly protected by CO2. Thus, the increase of phosphorylation cannot be attributed to peroxynitrite-mediated inhibition of phosphatases. We suggest that peroxynitrite may regulate the posttranslational modification of tyrosine residues in pre- and postsynaptic proteins. Identification of the major protein targets gives insight into the pathways possibly involved in neuronal degeneration associated with peroxynitrite overproduction.