Cells in action

This thesis documents a research program in which Australian grown Danshen extracts and related bioactive compounds have been demonstrated to be effective in scavenging free radicals, namely ROS generation, in a cell free system and NADPH oxidase derived superoxide (O2-) generation in vascular tissue (rat aorta). Danshen extracts, both aqueous and ethanol, and their active compounds (Tanshinone IIA, Salvianolic Acid B and Danshensu) demonstrated anti-oxidant activity however findings exhibited stronger activity in a cell free system than in the aortic vascular tissue.

138p runthenight07 01-03-2023 10 3   Download

Regulator of G-protein signaling (RGS) proteins were originally identified as negative regulators of G-protein-coupled receptor (GPCR) signaling via their GTPase-accelerating protein (GAP) activity. All RGS proteins contain evolutionarily conserved RGS domain; however, they differ in their size and regulatory domains. RGS1 and RGS10 are smaller than other RGS proteins, and their functions involve various inflammatory responses including autoimmune responses in both the periphery and the central nervous system (CNS). Neuroinflammation is the chronic inflammatory response in the CNS.

5p caothientrangnguyen 09-05-2020 28 2   Download

Agrobacterium tumefaciens is a Gram-negative, phytopathogenic bacterium and is characterized by an unique mode of action on dicotyledonous plants: it is able to genetically modify the host, and because of this feature, it is used as a tool for transgenic plants. Many experiments have demonstrated that lipopolysaccharides (LPSs) play an important role for the disease development, as they are involved in the adhesion process of the bacterium on the plant cell wall.

4p system191 01-06-2013 32 4   Download

Biozentrum-Pharmazie, Universitat Halle, Halle/Saale, Germany; 2Lehrstuhl fur Organische Chemie und Biochemie, Technische ¨ ¨ ¨ ¨ ¨ Universitat Munchen, Garching, Germany; 3Laboratorium fur Organische Chemie, Eidgenossische Technische Hochschule Honggerberg, ¨ Zurich, Switzerland 2C-Methyl-D -erythritol 2,4-cyclodiphosphate was recently shown to be formed from 2C-methyl-D -erythritol 4-phosphate by the consecutive action of IspD, IspE, and IspF proteins in the nonmevalonate pathway of terpenoid biosynthesis. ...

9p system191 01-06-2013 40 4   Download

We have analyzed several mathematical models that describe inhibition of the factor VIIa–tissue factor complex (VIIa–TF) by tissue factor pathway inhibitor (TFPI). At the core of these models is a common mechanism of TFPI action suggesting that only the Xa–TFPI complex is the inhibitor of the extrinsic tenase activity. However, the model based on this hypothesis could not explain well all the available experimental data. Here, we show that a good quantitative description of all experimental data could be achieved in a model that contains two more assumptions....

16p research12 01-06-2013 37 6   Download

Duodenase is a 29-kDa serine endopeptidase that displays selective trypsin- and chymotrypsin-like substrate specificity. This enzyme has been localized to epitheliocytes of Brunner’s glands, and as described here, to mast cells within the intestinal mucosa and lungworm-infected lung, implying an important additional role in inflammation and tissue remodelling. In primary cultures of pulmonary artery fibroblasts, duodenase induced a concentration-dependent increase in [3H]thymidine incorporation with a maximal effect observed at 30 nM.

10p research12 01-06-2013 53 3   Download

Insulin is the principal regulatory hormone involved in the tight regulation of fuel metabolism. In response to blood glucose levels, it is secreted by the b cells of the pancreas and exerts its effects by binding to cell surface receptors that are present on virtually all cell types and tissues. In humans, perturbations in insulin function and/or secretion lead to diabetes mellitus, a severe disorder primarily characterized by an inability to maintain blood glucose homeostasis. Furthermore, it is estimated that 90–95% of diabetic patients exhibit resistance to insulin action....

10p research12 01-06-2013 34 4   Download

We have previously demonstrated that the steroid hormone 1a,25(OH)2-vitamin D3 [1a,25(OH)2D3] stimulates the production ofinositol trisphosphate (InsP3), the breakdown product ofphosphatidylinositol 4,5-biphosphate (PtdInsP2) by phospholipase C (PtdIns-PLC), and activates the cyto-solic tyrosine kinase c-Src in skeletal muscle cells. In the present study we examined whether 1a,25(OH)2D3induces the phosphorylation and membrane translocation ofPLCc and the mechanism involved in this isozyme activation. ...

10p research12 29-04-2013 44 4   Download

Hexadecylphosphocholine (HePC) is a synthetic lipid rep-resentative of a new group of antiproliferative agents, alkylphosphocholines (APC), which are promising candi-dates in anticancer therapy. Thus we have studied the action of HePC on the human hepatoblastoma cell line HepG2, which is frequently used as a model for studies into hepatic lipid metabolism.

7p research12 23-04-2013 42 1   Download

ThenblAfamily of genes encodes for small proteins neces-sary for the ordered degradation of phycobilisomes under certain stress conditions, a process known as chlorosis. Genes homologous tonblAseem to occur in all phycobili-some-containingorganisms.However, todate, nomolecular mechanism is known for the action of NblA, nor have the gene products been characterized to understand the physical properties of the molecule and thus help elucidate the mechanism on a structural basis.

8p research12 23-04-2013 45 4   Download

The cAMP-dependent protein kinase (PKA) signaling pathway plays a major role in a number of pathophysio-logical conditions. However, there have been conflicting evidences regarding the action of cAMP/PKA on nuclear factor-jB(NF-jB). Inthis study,wehaveexplored the effect of cAMP/PKA on NF-jBactivity and determined its molecular mechanism. PKA activating agents or expression of thecatalyticsubunitofPKA(PKAc) inhibitedtheNF-jB-dependent reporter gene expression induced by tumor nec-rosis factora(TNFa). ...

7p research12 23-04-2013 33 4   Download

Microcin J25 (MccJ25) is the single macrocyclic antimicro-bial peptidebelonging to the ribosomally synthesizedclass of microcins that are secreted byEnterobacteriaceae.Itshowed potent antibacterial activity against severalSalmonellaand Escherichiastrains and exhibited a compact three-dimen-sional structure [Blondet al. (2001) Eur. J. Biochem., 268, 2124–2133]. The molecular mechanisms involved in the biosynthesis, folding andmode of action of MccJ25 are still unknown.

11p tumor12 22-04-2013 44 2   Download

Liver microsomal preparations are routinely used to predict drug interactions that can occurin vivo as a result of inhi-bition of cytochrome P450 (CYP)-mediated metabolism. However, the concentration of free drug (substrate and inhibitor)at its intrahepatic site of action, a variable that cannot be directly measured, may be significantly different from that in microsomal incubation systems.

10p tumor12 20-04-2013 47 4   Download

The dimeric structure of seminal ribonuclease (BS-RNase) is maintained by noncovalent interactions and by two intersubunit disulfide bridges.Another unusual feature of this enzyme is its antitumour action, consisting in a cyto-toxic activity selective for malignant cells.This cytotoxic action is exerted when the protein reaches the cytosol of the affected cells, where it degrades ribosomal RNA, thus blocking protein synthesis and leading cells to death.

8p fptmusic 16-04-2013 37 2   Download

Post ischaemic cell calcium invasion has been described as one of the main causes of graft failure. Protective effects of calcium antagonists have been investigated but are not con-vincing and their mechanisms of action remain unclear. In this work we tested the protective effect of a new calcium inhibitor described to block a calcium current insensitive to all known calcium blockers. Specific mapacalcine receptors were first characterized on rat hepatocytesmembranes using the 125 I-labeledmapacalcine....

6p fptmusic 16-04-2013 35 3   Download

The two-hybrid method detects the interaction of two proteins by their ability to reconstitute the activity of a split transcription factor, thus allow-ing the use of a simple growth selection in yeast to identify new inter-actions. Since its introduction about 15 years ago, the assay largely has been applied to single proteins, successfully uncovering thousands of novel protein partners.

9p fptmusic 12-04-2013 32 2   Download

Members of atRNA Gly 1 multigene family from the silkwormBombyx mori have been classified based on their transcriptions in homologous nuclear extracts, into three groups of highly, moderately and poorly transcribed genes. Because all these gene copies have identical coding sequences and consequently identical promoter elements (the A and B boxes), the flanking sequences modulate their expression levels. Here we demonstrate the inter-action of transcription factor TFIIIB with these genes and its role in regu-lating differential transcriptions....

15p fptmusic 12-04-2013 37 2   Download

Photodynamic treatment (PDT) is an emerging therapeutic procedure for the management of cancer, based on the use of photosensitizers, compounds that generate highly reactive oxygen species (ROS) on irradiation with visible light. The ROS generated may oxidize a variety of bio-molecules within the cell, loaded with a photosensitizer. The high reactivity of these ROS restricts their radius of action to 5–20 nm from the site of their generation.

7p fptmusic 12-04-2013 44 3   Download

Diacylglycerol (DAG) andproteinkinase C(PKC) isoforms have been implicated in insulin signalling in muscle and fat cells.We evaluated the involvement ofDAGandPKCin the action of insulin in adult rat hepatocytes culturedwith dexa-methasone, but in the absence of serum, for 48 h. Our results show that although insulin stimulated glycolysis and glycogen synthesis, it had no effect on DAG mass or molecular species composition.

12p fptmusic 12-04-2013 41 3   Download

Nicotinic acid adenine dinucleotide phosphate (NAADP) is a recently described Ca 2+ mobilizing messenger, and probably the most potent. We briefly review its unique properties as a Ca 2+ mobilizing agent. We present arguments for its action in targeting acidic calcium stores rather than the endoplasmic reticulum. Finally, we discuss possible biosynthetic pathways for NAADP in cells and candidates for its target Ca 2+ release channel, which has eluded identification so far.

9p fptmusic 11-04-2013 44 2   Download