Probe-based Assays
Probe-based Assays - Related Videos
04:02
An Assay to Measure the Accumulation of a Fluorescent Antibiotic Probe in Bacterial Cells
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2025
This video demonstrates an assay to measure the accumulation of a fluorescent antibiotic probe in bacterial cells. Exposure to an efflux pump inhibitor disrupts the transmembrane proton gradient in bacterial cells, upon which a fluorophore-conjugated antibiotic is added. Inhibition of efflux pumps due to the disrupted proton gradient causes accumulation of the antibiotic inside the bacteria. Bacterial cells are lysed, and the fluorescence intensity is measured to confirm antibiotic accumulation.
06:31
Probe-based Confocal Laser Endomicroscopy of the Urinary Tract: The Technique
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Cited by 25 •
2013
Probe-based confocal laser endomicroscopy enables real-time microscopy of the human urinary tract during cystoscopy, providing dynamic, intravital imaging of pathological states such as bladder cancer with cellular resolution. Endomicroscopy may augment the diagnostic accuracy of standard white light endoscopy and provide intraoperative image guidance to improve surgical resection.
11:01
Preparation and In Vivo Use of an Activity-based Probe for N-acylethanolamine Acid Amidase
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Cited by 3 •
2016
Here, we describe the preparation and use of an activity-based probe (ARN14686, undec-10-ynyl-N-[(3S)-2-oxoazetidin-3-yl]carbamate) that allows for the detection and quantification of the active form of the proinflammatory enzyme N-acylethanolamine acid amidase (NAAA), both in vitro and ex vivo.
02:38
Local Heat Probe Assay: A Method to Assess Nociception of High Temperatures in Drosophila Larvae
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2023
Drosophila larvae have dedicated sensory neurons–nociceptors–whose response to potentially harmful thermal stimuli triggers aversive–or so-called "nocifensive"–behaviors in the animal. This video describes a method to assess thermal nociception by recording larval behavior in response to local application of a heat probe onto the cuticle. This method is, therefore, called the local heat probe assay.
10:28
Probe-based Real-time PCR Approaches for Quantitative Measurement of microRNAs
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Cited by 33 •
2015
Circulating microRNAs have recently emerged as promising and novel biomarkers for various cancers and other diseases. The goal of this article is to discuss three different probe-based real-time PCR platforms and methods that are available to quantify and determine the abundance of circulating microRNAs.
FAQs
Probe recognition depends on matching the probe to a complementary nucleic acid sequence or another defined target molecule. This molecular fit helps distinguish the intended target from other substances in a sample, allowing the assay to focus on a particular microbial group, pathogen, genetic marker, or contaminant. Selective recognition is especially valuable when environmental samples contain many different molecules.
A label attached to the probe or associated with the detection system produces a measurable response after target recognition. Depending on the assay design, that response may be fluorescent, colorimetric, or electrochemical. The presence of a signal supports target detection, while signal intensity can provide an indication of relative target abundance when interpreted within the assay’s measurement framework.
Environmental samples from water, soil, and sediment contain mixtures of organisms, molecules, and other material that can complicate detection. Probe selectivity helps focus measurement on the chosen target rather than treating the entire sample as a single undifferentiated signal. This supports more informative assessments of microbial communities, pathogens, genetic markers, and contamination.
The target depends on the probe design. Some probes recognize complementary nucleic acid sequences, while others are directed toward different target molecules. This flexibility allows an assay to address biological and environmental questions involving microbial communities, pathogens, genetic markers, or contamination. Selecting the target determines which environmental condition or organism the resulting signal represents.
The process begins by selecting or designing a probe for the target of interest, applying it to an environmental sample, and allowing target recognition to occur. A label then generates a fluorescent, colorimetric, or electrochemical response that can be measured. The resulting signal is interpreted for target presence or, where appropriate, relative abundance.
Probe-based assays can be applied to water, soil, and sediment samples. Researchers may use them to monitor microbial communities, detect pathogens, identify genetic markers, or investigate contamination. Because the same general strategy can address different targets and sample types, it supports environmental studies ranging from biological community assessment to tracking changes in environmental conditions.
Measurements from these assays can help researchers assess ecosystem health, follow environmental change, and identify contamination-related patterns. Detection of a target or changes in its signal may provide evidence about the presence or relative abundance of organisms, markers, or contaminants. Such information can support contamination management by linking analytical observations with conditions in the sampled environment.