Inositol phosphates induce DAPI fluorescence shift

2014 ◽  
Vol 460 (3) ◽  
pp. 377-385 ◽  
Author(s):  
Bernadett Kolozsvari ◽  
Federica Parisi ◽  
Adolfo Saiardi
Keyword(s):  
Inositol Phosphates ◽  
Fluorescence Properties ◽  
Enzymatic Conversion ◽  
Dapi Fluorescence

The inositol phosphates IP5 and IP6 induce a specific DAPI fluorescence, whereas lower phosphorylated forms do not. The fluorescence properties of DAPI–IP5 and DAPI–IP6 complexes allow the easy assessment of the amounts and enzymatic conversion of these two important cellular messengers.

A cautionary (spectral) tail: red-shifted fluorescence by DAPI–DAPI interactions

2016 ◽  
Vol 44 (1) ◽  
pp. 46-49 ◽  
Author(s):  
Sidney Omelon ◽  
John Georgiou ◽  
Wouter Habraken
Keyword(s):  
Calcium Phosphate ◽  
Amorphous Calcium Phosphate ◽  
Electrostatic Interactions ◽  
Negative Charge ◽  
Inositol Phosphates ◽  
Fluorescence Emission ◽  
Spectral Shift ◽  
Polyadenylic Acid ◽  
Negative Charge Density ◽  
Dapi Fluorescence

The fluorescent dye DAPI is useful for its association with and consequent amplification of an ∼460 nm emission maximum upon binding to dsDNA. Labelling with higher DAPI concentrations is a technique used to reveal Pi polymers [polyphosphate (polyP)], with a red-shift to ∼520–550 nm fluorescence emission. DAPI–polyP emissions of ∼580 nm are also generated upon 415 nm excitation. Red-shifted DAPI emission has been associated with polyP and RNA and has more recently been reported with polyadenylic acid (polyA), specific inositol phosphates (IPs) and heparin. We find that amorphous calcium phosphate (ACP) also demonstrates red-shifted DAPI emission at high DAPI concentrations. This DAPI spectral shift has been attributed to DAPI–DAPI electrostatic interactions enabled by molecules with high negative charge density that increase the local DAPI concentration and favour DAPI molecular proximity, as observed by increasing the dye/phosphate ratio. Excitation of dry DAPI (∼360 nm) confirmed a red-shifted DAPI emission. Whereas enzymatic approaches to modify substrates can help define the nature of DAPI fluorescence signals, multiple approaches beyond red-shifted DAPI excitation/emission are advised before conclusions are drawn about DAPI substrate identification.

Fluorescence properties and stimulated emission in substituted europium chelates

1967 ◽  
Vol 64 ◽  
pp. 173-182 ◽  
Author(s):  
Erhard J. Schimitschek ◽  
Richard B. Nehrich Jr ◽  
John A. Trias
Keyword(s):  
Stimulated Emission ◽  
Fluorescence Properties ◽  
Europium Chelates

Eicosapentaenoic Acid Interferes with U46619-Stimulated Formation of Inositol Phosphates in Washed Rabbit Platelets

1989 ◽  
Vol 62 (04) ◽  
pp. 1116-1120 ◽  
Author(s):  
N Chetty ◽  
J D Vickers ◽  
R L Kinlough-Rathbone ◽  
M A Packham ◽  
J F Mustard
Keyword(s):  
Signal Transduction ◽  
Fatty Acid Composition ◽  
Eicosapentaenoic Acid ◽  
Inositol Phosphates ◽  
Inositol Phosphate ◽  
Dense Granule ◽  
Detectable Change ◽  
Membrane Phospholipids ◽  
Rabbit Platelets ◽  
Stimulation Of

SummaryEicosapentaenoic acid (EPA) inhibits platelet responsiveness to aggregating agents. To investigate the reactions that are affected by EPA, we examined the effect of preincubating aspirintreated rabbit platelets with EPA on stimulation of inositol phosphate formation in response to the TXA2 analogue U46619. Stimulation of platelets with U46619 (0.5 μM) caused aggregation and slight release of dense granule contents; aggregation and release were inhibited by preincubation of the platelets with EPA (50 μM) for 1 h followed by washing to remove unincorporated EPA. Incubation with EPA (50 μM) for 1 h did not cause a detectable increase in the amount of EPA in the platelet phospholipids. When platelets were prelabelled with [3H]inositol stimulation with U46619 of control platelets that had not been incubated with EPA significantly increased the labelling of mos1tol phosphates. The increases in inositol phosphate labelling due to U46619 at 10 and 60 s were partially inhibited by premcubat10n of the platelets with 50 μM EPA. Since the activity of cyclo-oxygenase was blocked with aspirin, inhibition of inositol phosphate labelling in response to U46619 indicates either that there may be inhibition of signal transduction without a detectable change in the amount of EPA in platelet phospholipids, that changes in signal transduction require only minute changes in the fatty acid composition of membrane phospholipids, or that after a 1 h incubation with EPA, activation of phospholipase C is affected by a mechanism that is not directly related to incorporation of EPA.

Fluorescence Properties of Pyrylretinol

2000 ◽  
Vol 72 (3) ◽  
pp. 415 ◽  
Author(s):  
Joydip Das ◽  
Rosalie K. Crouch ◽  
Parkson Lee-Gau Chong
Keyword(s):  
Fluorescence Properties

First Fluorescent Acetylspermidine Deacetylation Assay for HDAC10 Identifies Inhibitors of Neuroblastoma Cell Colony Growth That Increase Lysosome Accumulation

2020 ◽  
Author(s):  
Daniel Herp ◽  
Johannes Ridinger ◽  
Dina Robaa ◽  
Stephen A. Shinsky ◽  
Karin Schmidtkunz ◽  
...  
Keyword(s):  
Histone Deacetylases ◽  
High Throughput Screening ◽  
Neuroblastoma Cell ◽  
Hdac Inhibitors ◽  
Anticancer Therapy ◽  
Colony Growth ◽  
Autophagic Flux ◽  
Enzymatic Conversion ◽  
Lysine Deacetylase

Histone deacetylases (HDACs) are important epigenetic regulators involved in many diseases, esp. cancer. First HDAC inhibitors have been approved for anticancer therapy and many are in clinical trials. Among the 11 zinc-dependent HDACs, HDAC10 has received relatively little attention by drug discovery campaigns, despite its involvement e.g. in the pathogenesis of neuroblastoma. This is due in part to a lack of robust enzymatic conversion assays. In contrast to the protein lysine deacetylase and deacylase activity of the other HDAC subtypes, it has recently been shown that HDAC10 has strong preferences for deacetylation of oligoamine substrates like spermine or spermidine. Hence, it also termed a polyamine deacetylase (PDAC). Here, we present the first fluorescent enzymatic conversion assay for HDAC10 using an aminocoumarin labelled acetyl spermidine derivative to measure its PDAC activity, which is suitable for high-throughput screening. Using this assay, we identified potent inhibitors of HDAC10 mediated spermidine deacetylation in-vitro. Among those are potent inhibitors of neuroblastoma colony growth in culture that show accumulation of lysosomes, implicating disturbance of autophagic flux.

Enzyme-Instructed Self-assembly in Biological Milieu for Theranostics Purpose

2019 ◽  
Vol 26 (8) ◽  
pp. 1351-1365 ◽  
Author(s):  
Zhentao Huang ◽  
Qingxin Yao ◽  
Simin Wei ◽  
Jiali Chen ◽  
Yuan Gao
Keyword(s):  
Small Molecules ◽  
Precision Medicine ◽  
Self Assembly ◽  
Public Healthcare ◽  
Enzymatic Conversion ◽  
Vaccine Adjuvants ◽  
New Paradigm ◽  
Cancer Treatments ◽  
The Past ◽  
Biological Milieu

Precision medicine is in an urgent need for public healthcare. Among the past several decades, the flourishing development in nanotechnology significantly advances the realization of precision nanomedicine. Comparing to well-documented nanoparticlebased strategy, in this review, we focus on the strategy using enzyme instructed selfassembly (EISA) in biological milieu for theranostics purpose. In principle, the design of small molecules for EISA requires two aspects: (1) the substrate of enzyme of interest; and (2) self-assembly potency after enzymatic conversion. This strategy has shown its irreplaceable advantages in nanomedicne, specifically for cancer treatments and Vaccine Adjuvants. Interestingly, all the reported examples rely on only one kind of enzymehydrolase. Therefore, we envision that the application of EISA strategy just begins and will lead to a new paradigm in nanomedicine.

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