RF nonlinear interactions in living cells-II: Detection methods for spectral signatures

2003 ◽  
Vol 24 (7) ◽  
pp. 483-488 ◽  
Author(s):  
Quirino Balzano
Keyword(s):  
Living Cells ◽  
Detection Methods ◽  
Nonlinear Interactions ◽  
Spectral Signatures

Algoritmo de Descomposición Ciega Basado en el Modelo de Mezcla Multi-Lineal

2021 ◽  
Author(s):  
◽  
J. N. Mendoza Chavarría
Keyword(s):  
State Of The Art ◽  
Hyperspectral Data ◽  
Spectral Unmixing ◽  
Mixing Models ◽  
Nonlinear Interactions ◽  
Estimation Errors ◽  
Spectral Signatures ◽  
Scattering Effects ◽  
Linear Unmixing ◽  
Multiple Light Scattering

Spectral unmixing has proven to be a great tool for the analysis of hyperspectral data, with linear mixing models (LMMs) being the most used in the literature. Nevertheless, due to the limitations of the LMMs to accurately describe the multiple light scattering effects in multi and hyperspectral imaging, new mixing models have emerged to describe nonlinear interactions. In this paper, we propose a new nonlinear unmixing algorithm based on a multilinear mixture model called Non-linear Extended Blind Endmember and Abundance Extraction (NEBEAE), which is based on a linear unmixing method established in the literature. The results of this study show that proposed method decreases the estimation errors of the spectral signatures and abundance maps, as well as the execution time with respect the state of the art methods.

A near-infrared fluorescence turn-on probe based on Michael addition-intramolecular cyclization for specific detection of cysteine and its applications in environment water, milk and living cells

2021 ◽  
Author(s):  
Zhigang Gao ◽  
Ling Zhang ◽  
Minchuan Yan ◽  
Haibo Liu ◽  
Shaohui Lu ◽  
...  
Keyword(s):  
Intramolecular Cyclization ◽  
Michael Addition ◽  
Near Infrared ◽  
Living Cells ◽  
Detection Methods ◽  
Biological Functions ◽  
Specific Detection ◽  
Near Infrared Fluorescence ◽  
Turn On ◽  
Fluorescence Turn On

Owing to its important biological functions in many physiological and pathological processes, it is necessary to develop efficient and appropriate detection methods for monitoring the levels of Cys in biological...

scholarly journals High-Throughput Spectral and Lifetime-Based FRET Screening in Living Cells to Identify Small-Molecule Effectors of SERCA

2016 ◽  
Vol 22 (3) ◽  
pp. 262-273 ◽  
Author(s):  
Tory M. Schaaf ◽  
Kurt C. Peterson ◽  
Benjamin D. Grant ◽  
Prachi Bawaskar ◽  
Samantha Yuen ◽  
...  
Keyword(s):  
High Precision ◽  
Small Molecule ◽  
High Throughput ◽  
High Throughput Screening ◽  
Fluorescent Protein ◽  
Resonance Energy ◽  
Living Cells ◽  
Spectral Unmixing ◽  
Detection Methods ◽  
Response Curves

A robust high-throughput screening (HTS) strategy has been developed to discover small-molecule effectors targeting the sarco/endoplasmic reticulum calcium ATPase (SERCA), based on a fluorescence microplate reader that records both the nanosecond decay waveform (lifetime mode) and the complete emission spectrum (spectral mode), with high precision and speed. This spectral unmixing plate reader (SUPR) was used to screen libraries of small molecules with a fluorescence resonance energy transfer (FRET) biosensor expressed in living cells. Ligand binding was detected by FRET associated with structural rearrangements of green fluorescent protein (GFP, donor) and red fluorescent protein (RFP, acceptor) fused to the cardiac-specific SERCA2a isoform. The results demonstrate accurate quantitation of FRET along with high precision of hit identification. Fluorescence lifetime analysis resolved SERCA’s distinct structural states, providing a method to classify small-molecule chemotypes on the basis of their structural effect on the target. The spectral analysis was also applied to flag interference by fluorescent compounds. FRET hits were further evaluated for functional effects on SERCA’s ATPase activity via both a coupled-enzyme assay and a FRET-based calcium sensor. Concentration-response curves indicated excellent correlation between FRET and function. These complementary spectral and lifetime FRET detection methods offer an attractive combination of precision, speed, and resolution for HTS.

scholarly journals Exosomes as Powerful Engines in Cancer: Isolation, Characterization and Detection Techniques

Biosensors ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 518
Author(s):  
Marwa Gamal Saad ◽  
Haluk Beyenal ◽  
Wen-Ji Dong
Keyword(s):  
Drug Delivery ◽  
Cancer Metastasis ◽  
Living Cells ◽  
Detection Methods ◽  
Target Cells ◽  
Detection Techniques ◽  
Protective Environment ◽  
Physiological Pathways ◽  
Almost All ◽  
Novel Drug

Exosomes, powerful extracellular nanovesicles released from almost all types of living cells, are considered the communication engines (messengers) that control and reprogram physiological pathways inside target cells within a community or between different communities. The cell-like structure of these extracellular vesicles provides a protective environment for their proteins and DNA/RNA cargos, which serve as biomarkers for many malicious diseases, including infectious diseases and cancers. Cancer-derived exosomes control cancer metastasis, prognosis, and development. In addition to the unique structure of exosomes, their nanometer size and tendency of interacting with cells makes them a viable novel drug delivery solution. In recent years, numerous research efforts have been made to quantify and characterize disease-derived exosomes for diagnosis, monitoring, and therapeutic purposes. This review aims to (1) relate exosome biomarkers to their origins, (2) focus on current isolation and detection methods, (3) discuss and evaluate the proposed technologies deriving from exosome research for cancer treatment, and (4) form a conclusion about the prospects of the current exosome research.

scholarly journals Detection of Genomic Uracil Patterns

2021 ◽  
Vol 22 (8) ◽  
pp. 3902
Author(s):  
Angéla Békési ◽  
Eszter Holub ◽  
Hajnalka Laura Pálinkás ◽  
Beáta G. Vértessy
Keyword(s):  
Chemical Reactivity ◽  
Living Cells ◽  
Critical Assessment ◽  
Detection Methods ◽  
Special Focus ◽  
Cytosine Deamination ◽  
Genome Wide ◽  
Recent Developments ◽  
In Situ Detection

The appearance of uracil in the deoxyuridine moiety of DNA is among the most frequently occurring genomic modifications. Three different routes can result in genomic uracil, two of which do not require specific enzymes: spontaneous cytosine deamination due to the inherent chemical reactivity of living cells, and thymine-replacing incorporation upon nucleotide pool imbalances. There is also an enzymatic pathway of cytosine deamination with multiple DNA (cytosine) deaminases involved in this process. In order to describe potential roles of genomic uracil, it is of key importance to utilize efficient uracil-DNA detection methods. In this review, we provide a comprehensive and critical assessment of currently available uracil detection methods with special focus on genome-wide mapping solutions. Recent developments in PCR-based and in situ detection as well as the quantitation of genomic uracil are also discussed.

Nucleic Acid-Driven Aggregation-Induced Emission of Au Nanoclusters for Visualizing Telomerase Activity in Living Cells and In Vivo

2021 ◽  
Author(s):  
Xiang Ran ◽  
Zhenzhen Wang ◽  
Fang Pu ◽  
Enguo Ju ◽  
Jinsong Ren ◽  
...  
Keyword(s):  
Nucleic Acid ◽  
Cancer Cells ◽  
Clinical Diagnosis ◽  
Telomerase Activity ◽  
Living Cells ◽  
Detection Methods ◽  
Au Nanoclusters ◽  
Visual Monitoring

Visual monitoring of telomerase activity in living cancer cells and in vivo is essential for clinical diagnosis and treatment. However, most detection methods were performed in vitro due to the...

Fluorescence ratio imaging of dynamic intracellular ionic signals

1988 ◽  
Vol 46 ◽  
pp. 42-43
Author(s):  
R. Y. Tsien ◽  
A. Minta ◽  
M. Poenie ◽  
J.P.Y. Kao ◽  
A. Harootunian
Keyword(s):  
Binding Sites ◽  
Living Cells ◽  
Molecular Engineering ◽  
Ph Indicators ◽  
Highly Sensitive ◽  
Fluorescence Ratio Imaging ◽  
Ratio Imaging ◽  
Technical Advances ◽  
Indicator Dyes ◽  
Fluorescein Dyes

Recent technical advances now enable the continuous imaging of important ionic signals inside individual living cells with micron spatial resolution and subsecond time resolution. This methodology relies on the molecular engineering of indicator dyes whose fluorescence is strong and highly sensitive to ions such as Ca2+, H+, or Na+, or Mg2+. The Ca2+ indicators, exemplified by fura-2 and indo-1, derive their high affinity (Kd near 200 nM) and selectivity for Ca2+ to a versatile tetracarboxylate binding site3 modeled on and isosteric with the well known chelator EGTA. The most commonly used pH indicators are fluorescein dyes (such as BCECF) modified to adjust their pKa's and improve their retention inside cells. Na+ indicators are crown ethers with cavity sizes chosen to select Na+ over K+: Mg2+ indicators use tricarboxylate binding sites truncated from those of the Ca2+ chelators, resulting in a more compact arrangement of carboxylates to suit the smaller ion.

Application of FRAP and digitized fluorescence microscopy to problems in cell membrane dynamics

1988 ◽  
Vol 46 ◽  
pp. 118-119
Author(s):  
K. Jacobson ◽  
A. Ishihara ◽  
B. Holifield ◽  
F. Zhang
Keyword(s):  
Fluorescence Microscopy ◽  
Cell Biology ◽  
Extended Period ◽  
Dynamic Structure ◽  
Living Cells ◽  
Membrane Dynamics ◽  
Molecular Cell Biology ◽  
Image Averaging ◽  
Single Living Cells ◽  
Single Living

Our laboratory is concerned with understanding the dynamic structure of the plasma membrane with particular reference to the movement of membrane constituents during cell locomotion. In addition to the standard tools of molecular cell biology, we employ both fluorescence recovery after photo- bleaching (FRAP) and digitized fluorescence microscopy (DFM) to investigate individual cells. FRAP allows the measurement of translational mobility of membrane and cytoplasmic molecules in small regions of single, living cells. DFM is really a new form of light microscopy in that the distribution of individual classes of ions, molecules, and macromolecules can be followed in single, living cells. By employing fluorescent antibodies to defined antigens or fluorescent analogs of cellular constituents as well as ultrasensitive, electronic image detectors and video image averaging to improve signal to noise, fluorescent images of living cells can be acquired over an extended period without significant fading and loss of cell viability.

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