Acma Quenching Assay
Acma Quenching Assay - Related Videos
10:57
Quenching and Boiling
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2023
Source: Alexander S Rattner, Sanjay Adhikari, and Mahdi Nabil; Department of Mechanical and Nuclear Engineering, The Pennsylvania State University, University Park, PA Controlled heating followed by rapid cooling is an important element of many materials processing applications. This heat-treating procedure can increase material hardness, which is important for cutting tools or surfaces in high wear environments. The rapid cooling stage is called quenching, and is often performed by immersing...
07:47
Anti-virulent Disruption of Pathogenic Biofilms using Engineered Quorum-quenching Lactonases
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Cited by 7 •
2016
Quorum-quenching enzymes are anti-virulent and anti-bacterial options that can mitigate pathogenesis without risk of incurring resistance, by preventing the expression of virulence factors and genes associated with antibiotic resistance and biofilm formation. In this study, we report a method that demonstrates the efficacy of quorum-quenching enzymes in bacterial biofilm disruption.
08:58
Cerebral Blood Oxygenation Measurement Based on Oxygen-dependent Quenching of Phosphorescence
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Cited by 28 •
2011
We present an experimental procedure for measuring the partial pressure of oxygen (pO2) in cerebral vasculature based on oxygen-dependent quenching of phosphorescence. Animal preparation and imaging procedures were outlined for both large field of view CCD-based imaging of pO2 in rats and 2-photon excitation based imaging of pO2 in mice.
08:07
Sample Preparation for Single Cell Mass Spectrometry Metabolomics Studies: Combined Cell Washing, Quenching, Drying, and Storage
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Cited by 1 •
2025
This protocol aims to preserve cell metabolites for single-cell mass spectrometry (SCMS) by combining volatile salt solution washing, rapid liquid nitrogen quenching, freeze-drying, and −8 °C storage. It demonstrates that liquid nitrogen quenching is essential for maintaining metabolite profiles, while prolonged cold storage should be minimized to prevent metabolic alterations.
10:55
Fluorescence-quenching of a Liposomal-encapsulated Near-infrared Fluorophore as a Tool for In Vivo Optical Imaging
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Cited by 15 •
2015
The use of fluorophores for in vivo imaging can be greatly limited by opsonization, rapid clearance, low detection sensitivity and cytotoxic effects on the host. Encapsulation of fluorophores in liposomes by film hydration and extrusion leads to fluorescence quenching and protection which enables in vivo imaging with high detection sensitivity.
FAQs
As proton movement increases the acidity of an ACMA-containing compartment, the dye accumulates there and its fluorescence decreases through concentration-dependent quenching. The extent and progression of this signal change reflect formation or strengthening of the internal pH gradient. Monitoring fluorescence therefore provides a dynamic readout of proton transport rather than merely indicating whether a membrane is present.
A proton ionophore dissipates the pH gradient by allowing protons to move across the membrane, which reduces ACMA concentration in the acidic compartment and restores fluorescence. This recovery confirms that the preceding quench was linked to a proton gradient. Comparing quenching with ionophore-induced recovery helps separate proton-dependent transport signals from unrelated fluorescence changes.
Active proton pumping produces a progressive fluorescence quench as transport generates or reinforces an internal pH gradient. If the membrane is leaky, proton equilibration can weaken that gradient and limit sustained quenching. A subsequent fluorescence recovery after ionophore addition provides an additional test that the observed signal reflects proton-gradient behavior rather than nonspecific loss of fluorescence.
The assay depends on retaining a proton gradient within a biological or model membrane compartment. Excessive leakage can dissipate that gradient, reduce the magnitude or duration of fluorescence quenching, and obscure transporter activity. Consequently, quenching patterns must be interpreted together with the recovery response and the behavior of the membrane system being examined.
A typical workflow places ACMA with the biological or model membrane system, monitors fluorescence as proton transport proceeds, and then introduces a proton ionophore to collapse the gradient. The fluorescence trajectory before and after ionophore addition is compared. This sequence links signal loss to proton accumulation and signal recovery to gradient dissipation.
The assay can be applied to proton-translocating proteins, reconstituted membrane vesicles, and enzyme-driven transport systems. In each case, fluorescence changes provide information about whether the system can generate or alter a proton gradient across a membrane. This makes ACMA quenching useful for characterizing membrane energetics and comparing transporter activity in defined biochemical preparations.