112 research outputs found

    The chemical composition of egg plugs deposited by Sitophilus granarius L. females on grain

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    Over 20,000 egg plugs collected from infested wheat grain were subjected to chemical analysis.Elemental analysis showed a relatively high content of nitrogen (about 9%). It suggested that the predominant constituent of egg plugs is a protein. Spectrum obtained in ESI-MS analysis showed a series of peaks characteristic corresponding to protein of molecular weight 30073 Da. The appearance of other peaks in this spectrum suggests that studied protein is not homogenous. A sample of egg plugs incubated with pepsin yielded a complex mixture of peptides. The most abundant peak in the ESI-MS spectrum of zymatic hydrolysis products corresponds to peptide Mw 4560.76 Da. Chemical analysis indicated that the main component of egg plugs is protein. Keywords: egg plugs, chemical composition, Sitophilus granariu

    The Hydrogen–Deuterium Exchange at α-Carbon Atom in N,N,N-Trialkylglycine Residue: ESI-MS Studies

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    Derivatization of peptides as quaternary ammonium salts (QAS) is a known method for sensitive detection by electrospray ionization tandem mass spectrometry. Hydrogens at α-carbon atom in N,N,N-trialkylglycine residue can be easily exchanged by deuterons. The exchange reaction is base-catalyzed and is dramatically slow at lower pH. Introduced deuterons are stable in acidic aqueous solution and are not back-exchanged during LC-MS analysis. Increased ionization efficiency, provided by the fixed positive charge on QAS group, as well as the deuterium labeling, enables the analysis of trace amounts of peptides

    Hydroxypyridinones with enhanced iron chelating properties. Synthesis, characterization and in vivo tests of 5-hydroxy-2-(hydroxymethyl)pyridine-4(1H)-one

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    The synthesis of 5-hydroxy-2-(hydroxymethyl)pyridin-4(1H)-one (P1) is presented, together with the evaluation of its coordination ability towards Fe3+, studied by a combination of chemical, computational, and animal approaches. The use of complementary analytical techniques has allowed us to give evidence of the tautomeric changes of P1 as a function of pH, and to determine their influence on the coordinating ability of P1 towards Fe3+. The pFe3+ value 22.0 of P1–iron complexes is noticeably higher than that of deferiprone (20.6), one of the three clinical chelating agents in therapeutic use for iron overload diseases. This is due on one side to the tautomeric change to the catechol form, and on the other to the lower protonation constant of the OH group. Bio-distribution studies on mice allowed us to confirm in vivo the efficacy of P1. Furthermore the coordinating ability toward Al3+, Cu2+ and Zn2+ has been studied to evalu- ate the possible use of P1 against a second toxic metal ion (Al3+), and to envisage its potential influence on the homeostatic equilibria of essential metal ions. The chelating ability of P1 toward these ions, not higher than that of the corresponding deferiprone, contributes to render P1 a more selective iron chelato

    Caveolin-1 enhances resveratrol-mediated cytotoxicity and transport in a hepatocellular carcinoma model

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    <p>Abstract</p> <p>Background</p> <p>Resveratrol (RES), an estrogen analog, is considered as a potential cancer chemo-preventive agent. However, it remains unclear how RES is transported into cells. In this study, we observed that Caveolin-1(CAV1) expression can increase the cytotoxic and pro-apoptotic activity of RES in a dose- and time-dependent manner both <it>in vitro </it>and <it>in vivo </it>in a Hepatocellular Carcinoma animal model.</p> <p>Methods</p> <p>High performance liquid chromatography (HPLC) demonstrated that RES intra-cellular concentration is increased about 2-fold in cells stably expressing CAV1 or CAVM1 (a scaffolding domain (81-101AA)-defective CAV1 mutant) compared to the untransduced human Hepatoblastoma cell line (HepG2) or after transduction with the green fluorescent protein (GFP) control vector. The increased intra-cellular transport of RES was abolished in cells stably expressing CAVM2 (a cholesterol shuttle domain (143-156AA)-defective CAV1 mutant) or CAVRNAi. In order to further characterize CAV1-dependent RES transport, we synthesized RES-dansyl chloride derivatives as fluorescent probes to visualize the transport process, which demonstrated a distribution consistent with that of CAV1 in HepG2 cells.</p> <p>Results</p> <p>In addition, RES endocytosis was not mediated by estrogen receptor (ER) α and β, as suggested by lack of competitive inhibition by estrogen or Tamoxifen. Pathway analysis showed that RES can up-regulate the expression of endogenous CAV1; this activates further the MAPK pathway and caspase-3 expression.</p> <p>Discussion</p> <p>This study provides novel insights about the role played by CAV1 in modulating cellular sensitivity to RES through enhancement of its internalization and trafficking.</p

    Resveratrol Enhances Antitumor Activity of TRAIL in Prostate Cancer Xenografts through Activation of FOXO Transcription Factor

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    Resveratrol (3, 4', 5 tri-hydroxystilbene), a naturally occurring polyphenol, exhibits anti-inflammatory, antioxidant, cardioprotective and antitumor activities. We have recently shown that resveratrol can enhance the apoptosis-inducing potential of TRAIL in prostate cancer cells through multiple mechanisms in vitro. Therefore, the present study was designed to validate whether resveratrol can enhance the apoptosis-inducing potential of TRAIL in a xenograft model of prostate cancer.Resveratrol and TRAIL alone inhibited growth of PC-3 xenografts in nude mice by inhibiting tumor cell proliferation (PCNA and Ki67 staining) and inducing apoptosis (TUNEL staining). The combination of resveratrol and TRAIL was more effective in inhibiting tumor growth than single agent alone. In xenografted tumors, resveratrol upregulated the expressions of TRAIL-R1/DR4, TRAIL-R2/DR5, Bax and p27(/KIP1), and inhibited the expression of Bcl-2 and cyclin D1. Treatment of mice with resveratrol and TRAIL alone inhibited angiogenesis (as demonstrated by reduced number of blood vessels, and VEGF and VEGFR2 positive cells) and markers of metastasis (MMP-2 and MMP-9). The combination of resveratrol with TRAIL further inhibited number of blood vessels in tumors, and circulating endothelial growth factor receptor 2-positive endothelial cells than single agent alone. Furthermore, resveratrol inhibited the cytoplasmic phosphorylation of FKHRL1 resulting in its enhanced activation as demonstrated by increased DNA binding activity.These data suggest that resveratrol can enhance the apoptosis-inducing potential of TRAIL by activating FKHRL1 and its target genes. The ability of resveratrol to inhibit tumor growth, metastasis and angiogenesis, and enhance the therapeutic potential of TRAIL suggests that resveratrol alone or in combination with TRAIL can be used for the management of prostate cancer

    Epigenetic assays for chemical biology and drug discovery

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    Comparison of nest site selection in Mute Swan Cygnus olor and the expanding Whooper Swan Cygnus cygnus

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    The warming climate is giving migratory birds new opportunities to extend their breeding ranges. These expansions may have a significant impact on other local bird communities. Here, we investigate the nest site selection of Mute Swan Cygnus olor, and the expanding Whooper Swan Cygnus cygnus. The study aims to assess the differences in habitat use by these two swan species in a lowland anthropogenic landscape. It examines the number of breeding pairs and the surface areas of nesting zones in different habitat types. The field procedures involved the use of unmanned aerial vehicles (UAVs) to survey and locate nests, with geotagged photographs taken to map nest locations. Our results show that Mute Swans primarily occupy oxbows, while Whooper Swans predominantly nest in pond complexes. Moreover, GLM models indicate that Mute Swans tend to choose open areas within a radius of 200 m around the nests, whereas Whooper Swans avoid built-up areas, often choosing forested sites within a radius of 500 m of their nests. These findings suggest that the expansion of the Whooper Swan population has led to changes in the breeding behaviour and habitat use of sympatric Mute Swan populations. The territorial behaviour and aggression of Whooper Swan may be driving Mute Swan away from fishpond habitats. We conclude that interactions between the two swan species are dynamic and have not yet stabilized, so this is an issue that needs to be closely monitored. Understanding these dynamics is essential for the effective conservation and management of wetland habitats in the face of ongoing climate change and shifting breeding ranges of birds

    Information Exchange Automation in Maritime Transport

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    To ensure the safety of maritime transport the access to information must be provided through a commonly used services. However, an equally important task is to determine or agree on interpretation of incoming data and assessment of a current and predicted navigational situation and, in further step, intentions of the participants in the transport process. Thanks to the standardization of information format, automatic information exchange gets increasingly wider. Another step ahead is automatic interpretation of information and automation of negotiation processes - intelligent communication. Rapid development of IT and ICT technologies creates such opportunities. This article presents the results of research on a system of automatic communication and co-operation in maritime transport
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