Search results for "adenosine triphosphate"

ATP and endogenous agonists inhibit evoked [3H]-noradrenaline release in rat iris via A1 and P2y-like purinoceptors.

1993

Effects of ATP, adenosine and purinoceptor antagonists on field stimulation-evoked (3 Hz, 2 min) [3H]-noradrenaline overflow were investigated in the rat isolated iris. ATP and adenosine inhibited the evoked overflow of [3H]-noradrenaline. 1,3-Dipropyl-8-cyclopentylxanthine (DPCPX) shifted the concentration-response curve of ATP to the right in a concentration-dependent manner, but with a potency (-log KB = 7.88) much lower than expected for an A1 adenosine receptor. In the continuous presence of DPCPX, the ATP-induced prejunctional inhibition was unaffected by suramin (100 mumol/l) and DIDS (4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid, 50 mumol/l) but was antagonized by the P2Y-rece…

Evidence for the presence of P2y and P2x receptors with different functions in mouse stomach.

2005

To clarify the function of P2 receptor subtypes in mouse stomach, the motor responses to ATP, alpha,beta-methyleneATP (alpha,beta-MeATP), P2X receptor agonist, 2-methylthioATP (2-MeSATP), P2Y receptor agonist, and the effects of the desensitisation of P2X receptors with alpha,beta-MeATP and of P2Y receptors with ADPbetaS were analysed recording the endoluminal pressure from whole-organ. ATP-induced relaxation was antagonised by suramin, non-selective P2 receptor antagonist, by desensitisation of P2Y receptors with ADPbetaS, and increased by desensitisation of P2X receptors with alpha,beta-MeATP. alpha,beta-MeATP produced biphasic responses: relaxation, reduced by P2X- or P2Y desensitisation…

Mitochondrial glutathione depletion by glutamine in growing tumor cells.

2000

The effect of L-glutamine (Gln) on mitochondrial glutathione (mtGSH) levels in tumor cells was studied in vivo in Ehrlich ascites tumor (EAT)-bearing mice. Tumor growth was similar in mice fed a Gln-enriched diet (GED; where 30% of the total dietary nitrogen was from Gln) or a nutritionally complete elemental diet (SD). As compared with non-tumor-bearing mice, tumor growth caused a decrease of blood Gln levels in mice fed an SD but not in those fed a GED. Tumor cells in mice fed a GED showed higher glutaminase and lower Gln synthetase activities than did cells isolated from mice fed an SD. Cytosolic glutamate concentration was 2-fold higher in tumor cells from mice fed a GED ( approximately…

The New Microtubule-Targeting Agent SIX2G Induces Immunogenic Cell Death in Multiple Myeloma

2022

Microtubule-targeting agents (MTAs) are effective drugs for cancer treatment. A novel diaryl [1,2]oxazole class of compounds binding the colchicine site was synthesized as cis-restricted-combretastatin-A-4-analogue and then chemically modified to have improved solubility and a wider therapeutic index as compared to vinca alkaloids and taxanes. On these bases, a new class of tricyclic compounds, containing the [1,2]oxazole ring and an isoindole moiety, has been synthetized, among which SIX2G emerged as improved MTA. Several findings highlighted the ability of some chemotherapeutics to induce immunogenic cell death (ICD), which is defined by the cell surface translocation of Calreticulin (CAL…

Alteration of the Mitochondrial Effects of Ceria Nanoparticles by Gold: An Approach for the Mitochondrial Modulation of Cells Based on Nanomedicine

2020

Ceria nanoparticles are cell compatible antioxidants whose activity can be enhanced by gold deposition and by surface functionalization with positive triphenylphosphonium units to selectively target the mitochondria. The antioxidant properties of these nanoparticles can serve as the basis of a new strategy for the treatment of several disorders exhibiting oxidative stress, such as cancer, diabetes or Alzheimer&rsquo

Energetic coupling between plastids and mitochondria drives CO2 assimilation in diatoms.

2015

International audience; Diatoms are one of the most ecologically successful classes of photosynthetic marine eukaryotes in the contemporary oceans. Over the past 30 million years, they have helped to moderate Earth's climate by absorbing carbon dioxide from the atmosphere, sequestering it via the biological carbon pump and ultimately burying organic carbon in the lithosphere. The proportion of planetary primary production by diatoms in the modern oceans is roughly equivalent to that of terrestrial rainforests. In photosynthesis, the efficient conversion of carbon dioxide into organic matter requires a tight control of the ATP/NADPH ratio which, in other photosynthetic organisms, relies prin…

The inhibition of Ca2+-ATPases of human erythrocyte membranes by covalent binding of ATP derivatives.

1982

UV-induced cross-linking of Tet repressor to DNA containing tet operator sequences and 8-azidoadenines.

1990

The synthesis of 8-azido-2'-deoxyadenosine-5'-triphosphate is described. The photoreactive dATP analog was characterized by thin layer chromatography, proton resonance spectroscopy, infrared spectroscopy and UV spectroscopy. Its photolysis upon UV irradiation was studied. After incorporation of this dATP analog into DNA containing the tet operator sequence the investigation of the interactions between tet operator DNA and Tet repressor protein by UV photocross-linking becomes possible. Photocross-linking of protein to DNA was demonstrated by the reduced migration of the DNA in SDS polyacrylamide gel electrophoresis. Addition of the inducer tetracycline prior to UV irradiation significantly …

The Low-Affinity ATP Binding Site of the Escherichia coli SecA Dimer Is Localized at the Subunit Interface

1997

The homodimeric SecA protein is the ATP-dependent force generator in the Escherichia coli precursor protein translocation cascade. SecA contains two essential nucleotide binding sites (NBSs), i.e., NBS1 and NBS2 that hind ATP with high and low affinity, respectively. The photoactivatable bifunctional cross-linking agent 3'-arylazido-8-azidoadenosine 5'-triphosphate (diN(3)ATP) was used to investigate the spatial arrangement of the nucleotide binding sites of SecA, DiN(3)ATP is an authentic ATP analogue as it supports SecA-dependent precursor protein translocation and translocation ATPase, UV-induced photo-cross-linking of the diN(3)ATP-bound SecA results in the formation of stable dimeric s…

Low light level in vitro monitoring of cellular and antigen-antibody reactions using a photon detection camera system — New perspectives for clinical…

1990

This article briefly describes the use of a photon counting system (ARGUS-100) in the detection of low levels of light. The ARGUS-100 was used in determining ATP in cell sections from tumor tissues and in measuring a luminescence-enhanced immunoluminometric assay, using ferritin as the analyte, based on the luminol-peroxide-4-iodophenol reaction with peroxidase as the enzyme. The aim is not so much the presentation of data, but rather to show the potentials of the photon counting camera in increasing our knowledge of the cellular and subcellular levels, as well as lowering the detection limits in already sensitive systems, such as immunoassays.