Search results for "Heterocyclic Compounds"
showing 10 items of 374 documents
Towards the synthesis of substituted porphyrins by a pyridyl group bearing a reactive functionality
2010
Pyridyl-substituted porphyrins bearing a reactive functionality were prepared via Suzuki cross-coupling reactions and resulted in very good yields. These compounds are precursors of new porphyrin architectures able to coordinate two metals: one in the porphyrin core and the second around the pyridyl moiety. During the coupling reactions, a higher reactivity of a chloro picolyl group was evidenced compared to a bromo function on the same reacting molecule.
Self-assembled Pt2L2 boxes strongly bind G-quadruplex DNA and influence gene expression in cancer cells
2017
Supramolecular Pt(ii) quadrangular boxes bind native and G-quadruplex DNA motifs in a size-dependent fashion. Three Pt molecular squares of distinct size show biological activity against cancer cells and heavily influence the expression of genes known to form G-quadruplexes in their promoter regions. The smallest Pt-box displays less activity but more selectivity for a quadruplex formed in the c-Kit gene.
Activation of the plant plasma membrane H+ -ATPase. Is there a direct interaction between lysophosphatidylcholine and the C-terminal part of the enzy…
1996
The antagonistic effects of the fungal toxin beticolin-1 and of L-alpha-lysophosphatidylcholine (lysoPC) were investigated on the plasma membrane H+-ATPase of the plant Arabidopsis thaliana (isoform 2) expressed in yeast, using both wild-type enzyme (AHA2) and C-terminal truncated enzyme (aha2delta92). Phosphohydrolytic activities of both enzymes were inhibited by beticolin-1, with very similar 50% inhibitory concentrations, indicating that the toxin action does not involve the C-terminal located autoinhibitory domain of the proton pump. Egg lysoPC, a compound that activates the H+-ATPase by a mechanism involving the C-terminal part of the protein, was found to be able to reverse the inhibi…
Magnesium ions promote assembly of channel-like structures from beticolin 0, a non-peptide fungal toxin purified from Cercospora beticola.
1998
Beticolins are toxins produced by the fungus Cercospora beticola. Using beticolin 0 (B0), we have produced a strong and Mg(2+)-dependent increase in the membrane conductance of Arabidopsis protoplasts and Xenopus oocytes. In protein-free artificial bilayers, discrete deflexions of current were observed (12 pS unitary conductance in symmetrical 100 mM KCl) in the presence of B0 (approximately 10 microM) and in the presence of nominal Mg2+. Addition of 50 microM Mg2+ induced a macroscopic current which could be reversed to single channel current by chelating Mg2+ with EDTA. Both unitary and macroscopic currents were ohmic. The increase in conductance of biological membranes triggered by B0 is…
ABP1 Mediates Auxin Inhibition of Clathrin-Dependent Endocytosis in Arabidopsis
2010
SummarySpatial distribution of the plant hormone auxin regulates multiple aspects of plant development. These self-regulating auxin gradients are established by the action of PIN auxin transporters, whose activity is regulated by their constitutive cycling between the plasma membrane and endosomes. Here, we show that auxin signaling by the auxin receptor AUXIN-BINDING PROTEIN 1 (ABP1) inhibits the clathrin-mediated internalization of PIN proteins. ABP1 acts as a positive factor in clathrin recruitment to the plasma membrane, thereby promoting endocytosis. Auxin binding to ABP1 interferes with this action and leads to the inhibition of clathrin-mediated endocytosis. Our study demonstrates th…
Systematic analysis of specific and nonspecific auxin effects on endocytosis and trafficking.
2021
Abstract The phytohormone auxin and its directional transport through tissues are intensively studied. However, a mechanistic understanding of auxin-mediated feedback on endocytosis and polar distribution of PIN auxin transporters remains limited due to contradictory observations and interpretations. Here, we used state-of-the-art methods to reexamine the auxin effects on PIN endocytic trafficking. We used high auxin concentrations or longer treatments versus lower concentrations and shorter treatments of natural indole-3-acetic acid (IAA) and synthetic naphthalene acetic acid (NAA) auxins to distinguish between specific and nonspecific effects. Longer treatments of both auxins interfere wi…
Green Tea Catechins Induce Inhibition of PTP1B Phosphatase in Breast Cancer Cells with Potent Anti-Cancer Properties: In Vitro Assay, Molecular Docki…
2020
The catechins derived from green tea possess antioxidant activity and may have a potentially anticancer effect. PTP1B is tyrosine phosphatase that is oxidative stress regulated and is involved with prooncogenic pathways leading to the formation of a.o. breast cancer. Here, we present the effect of selected green tea catechins on enzymatic activity of PTP1B phosphatase and viability of MCF-7 breast cancer cells. We showed also the computational analysis of the most effective catechin binding with a PTP1B molecule. We observed that epigallocatechin, epigallocatechin gallate, epicatechin, and epicatechin gallate may decrease enzymatic activity of PTP1B phosphatase and viability of MCF-7 cells.…
AMD3100: A Versatile Platform for CXCR4 Targeting 68 Ga-Based Radiopharmaceuticals
2016
International audience; CXCR4 is a G protein-coupled receptor (GPCR), which is overexpressed in numerous diseases, particularly in multiple cancers. Therefore, this receptor represents a valuable target for imaging and therapeutic purposes. Among the different approaches, which were developed for CXCR4 imaging, a CXCR4 antagonist biscyclam system (AMD3100, also called Mozobil), currently used in the clinic for the mobilization of hematopoietic stem cells, was radiolabeled with different radiometals such as 62Zn, 64Cu, 67Ga, or 99mTc. However, cyclam is not an ideal chelator for most of these radiometals, and could lead to the release of the radionuclide in vivo. In the current study, a new …
Recent discoveries of anticancer flavonoids.
2017
Abstract In this review we report the recent advances in anticancer activity of the family of natural occurring flavonoids, covering the time span of the last five years. The bibliographic data will be grouped, on the basis of biological information, in two great categories: reports in which the extract plants bioactivity is reported and the identification of each flavonoid is present or not, and reports in which the anticancer activity is attributable to purified and identified flavonoids from plants. Wherever possible, the targets and mechanisms of action as well as the structure-activity relationships of the molecules will be reported. Also, in the review it was thoroughly investigated t…
On the Use of Binary Trees for DNA Hydroxymethylation Analysis
2017
DNA methylation (mC) and hydroxymethylation (hmC) can have a significant effect on normal human development, health and disease status. Hydroxymethylation studies require specific treatment of DNA, as well as software tools for their analysis. In this paper, we propose a parallel software tool for analyzing the DNA hydroxymethylation data obtained by TAB-seq. The software is based on the use of binary trees for searching the different occurrences of methylation and hydroxymethylation in DNA samples. The binary trees allow to efficiently store and access the information about the methylation of each methylated/hydroxymethylated cytosines in the samples. Evaluation results shows that the perf…