CHA-based DNA stochastic walker that traverses on cell membranes

Nanoscale ◽  
2021 ◽  
Author(s):  
Yanlei Hu ◽  
Xia Chu
Keyword(s):  
Nucleic Acid ◽  
Cell Membranes ◽  
Dna Walker ◽  
Protein Motors

DNA walker, imitating protein motors, is a class of nucleic acid nanodevices and can move along a precisely defined “track”. With promising future in materials and biotechnology, DNA walker has...

A novel fluorescent assay for the ultrasensitive detection of miRNA-21 with the use of G-quadruplex structures as an immobilization material for a signal indicator

2019 ◽  
Vol 55 (45) ◽  
pp. 6453-6456 ◽  
Author(s):  
Ze-Zhou Yang ◽  
Zhi-Bin Wen ◽  
Xin Peng ◽  
Ya-Qin Chai ◽  
Wen-Bin Liang ◽  
...  
Keyword(s):  
Nucleic Acid ◽  
Three Dimensional ◽  
Nucleic Acid Amplification ◽  
Ultrasensitive Detection ◽  
Fluorescent Assay ◽  
Target Recycling ◽  
Dna Walker ◽  
G Quadruplex

A fluorescent assay for the ultrasensitive detection of miRNA-21 is based on immobilization of PPIX as signal indicators in massive G-quadruplex structures obtained by target recycling, three-dimensional DNA walker and RCA coupled cascade nucleic acid amplification.

Novel Reagents for the Addition of Viability Measurements to Immunostaining Using Flow Cytometry.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 3879-3879
Author(s):  
Gayle M. Buller ◽  
Jolene A. Bradford ◽  
Jixiang Liu ◽  
William L. Godfrey
Keyword(s):  
Flow Cytometry ◽  
Nucleic Acid ◽  
Propidium Iodide ◽  
Cell Membranes ◽  
Fluorescent Dyes ◽  
Jurkat Cells ◽  
Dead Cell ◽  
Acetoxymethyl Ester ◽  
Alexa Fluor ◽  
Red Dye

Abstract With polychromatic flow cytometry becoming more prevalent, there is increasing interest in excluding dead cells from analyses without sacrificing the fluorophores already in use. We report several novel organic dyes that can identify stressed or dead cells in stained populations without compromising channels used for common fluorophores such as Alexa Fluor® 488, R-phycoerythrin (R-PE) and R-PE tandem dyes. Fixable violet and fixable aqua dead cell stains been developed that have peak emissions around 450 and 515 nm, respectively, and which can withstand aldehyde fixation, allowing their use with surface and intracellular labeling protocols. These amine reactive fluorescent dyes covalently label dead cells more brightly than live cells because the dye stains the cytoplasm of cells that have lost membrane integrity. (Figure 1A) These dyes stain equivalent dead cell populations versus ethidium monoazide bromide (EMA), but they do not require the additional photolysis step to cross-link EMA to the DNA of dead cells. SYTOX® red dead cell stain is a high-affinity nucleic acid stain that penetrates cells with damaged cell membranes, but will not cross uncompromised cell membranes. Cells stained with SYTOX red dye fluoresce bright red when excited with a red diode laser (Figure 1B), and can be used with fluorophores such as Alexa Fluor 488 dye and R-PE with little need for spectral correction. These properties, combined with a greater than 500-fold increase in fluorescence upon nucleic acid binding, make SYTOX red an optimal dead cell stain for use in flow cytometers equipped with red lasers. For measures of vitality, CellTrace™ calcein violet,AM dye is a metabolic probe that indicates intracellular esterase activity through the enzymatic conversion of the nonfluorescent, cell-permeant acetoxymethyl ester (AM) to a fluorescent violet-excited dye that is retained in the cell and emits fluorescence around 440 nm. Calcein violet,AM shows similar performance to calcein, AM, a common vitality reagent in flow cytometry and microscopy, and can be used in combination with impermeant DNA dyes such as SYTOX red dye or propidium iodide to identify live, injured and dead cells. (Figure 1C) For a violet-excited live/dead assay, the fixable aqua dead cell stain, with peak emission around 515 nm, can be combined with calcein violet,AM. Calcein violet,AM also can be used with Alexa Fluor 488 annexin V and propidium iodide to add a measure of enzymatic activity to the study of apoptosis. Together, these reagents provide multiple methods to add viability and vitality discrimination into standard immunostaining panels. Figure 1. Mixed live and heat-killed Jurkat cells stained with (A) fixable violet dead cell stain, (B) SYTOX red stain, and (C) a mixture of calcein violet,AM and SYTOX red dye. Figure 1. Mixed live and heat-killed Jurkat cells stained with (A) fixable violet dead cell stain, (B) SYTOX red stain, and (C) a mixture of calcein violet,AM and SYTOX red dye.

Deoxyribonucleic Nucleic Acid Anchored on Cell Membranes for Biomedical Applications

2021 ◽  
Author(s):  
Qunye He ◽  
Yanfei Liu ◽  
Ke Li ◽  
Yuwei Wu ◽  
Ting Wang ◽  
...  
Keyword(s):  
Nucleic Acid ◽  
Biomedical Applications ◽  
Cell Membranes ◽  
Cellular Membrane ◽  
Molecular Tool ◽  
Cellular Behaviors

Engineering cellular membrane with functional molecules provides an attractive strategy to manipulate cellular behaviors and functionalities. Currently, synthetic deoxyribonucleic nucleic acid (DNA) has been emerged as a promising molecular tool...

scholarly journals A smart fluorescent biosensor for the highly sensitive detection of BRCA1 based on a 3D DNA walker and ESDR cascade amplification

RSC Advances ◽  
2019 ◽  
Vol 9 (34) ◽  
pp. 19347-19353 ◽  
Author(s):  
Hongmin Ma ◽  
Bin Guo ◽  
Xiaoyu Yan ◽  
Tong Wang ◽  
Haiying Que ◽  
...  
Keyword(s):  
Nucleic Acid ◽  
Sensitive Detection ◽  
Fluorescent Biosensor ◽  
Dna Walker ◽  
Highly Sensitive ◽  
Nucleic Acid Analysis ◽  
Highly Sensitive Detection ◽  
Cascade Amplification ◽  
Diagnosis Of Diseases

Nucleic acid analysis plays an important role in the diagnosis of diseases.

DNA-fueled target recycling-induced two-leg DNA walker for amplified electrochemical detection of nucleic acid

Talanta ◽  
2018 ◽  
Vol 188 ◽  
pp. 685-690 ◽  
Author(s):  
Kun Wang ◽  
Min Feng ◽  
Meng-Qi He ◽  
Fu-Heng Zhai ◽  
Yu Dai ◽  
...  
Keyword(s):  
Nucleic Acid ◽  
Electrochemical Detection ◽  
Target Recycling ◽  
Dna Walker

An anchored monopodial DNA walker triggered by proximity hybridization for amplified amperometric biosensing of nucleic acid and protein

2020 ◽  
Vol 1107 ◽  
pp. 48-54
Author(s):  
Yi Man ◽  
Jinbo Liu ◽  
Jie Wu ◽  
Li Yin ◽  
Hua Pei ◽  
...  
Keyword(s):  
Nucleic Acid ◽  
Dna Walker

Photoreceptor disk membrane substructures by means of the complementary freeze-fracture-replica methods

1978 ◽  
Vol 36 (2) ◽  
pp. 156-157
Author(s):  
A. Tonosaki ◽  
M. Yamasaki ◽  
H. Washioka ◽  
J. Mizoguchi
Keyword(s):  
Cell Membranes ◽  
Freeze Fracture ◽  
Purple Membrane ◽  
Remarkable Case ◽  
Single Face ◽  
Disk Membrane ◽  
Associated Proteins ◽  
Photoreceptor Membranes

A vertebrate disk membrane is composed of 40 % lipids and 60 % proteins. Its fracture faces have been classed into the plasmic (PF) and exoplasmic faces (EF), complementary with each other, like those of most other types of cell membranes. The hypothesis assuming the PF particles as representing membrane-associated proteins has been challenged by serious questions if they in fact emerge from the crystalline formation or decoration effects during freezing and shadowing processes. This problem seems to be yet unanswered, despite the remarkable case of the purple membrane of Halobacterium, partly because most observations have been made on the replicas from a single face of specimen, and partly because, in the case of photoreceptor membranes, the conformation of a rhodopsin and its relatives remains yet uncertain. The former defect seems to be partially fulfilled with complementary replica methods.

Introduction

1978 ◽  
Vol 36 (3) ◽  
pp. 543-544
Author(s):  
W. Bernard
Keyword(s):  
Molecular Weight ◽  
Electron Microscope ◽  
Nucleic Acid ◽  
Gene Mapping ◽  
Molecular Genetics ◽  
Cell Biology ◽  
Gene Activity ◽  
Close Connection ◽  
Basic Information ◽  
Simple Systems

In comparison to many other fields of ultrastructural research in Cell Biology, the successful exploration of genes and gene activity with the electron microscope in higher organisms is a late conquest. Nucleic acid molecules of Prokaryotes could be successfully visualized already since the early sixties, thanks to the Kleinschmidt spreading technique - and much basic information was obtained concerning the shape, length, molecular weight of viral, mitochondrial and chloroplast nucleic acid. Later, additonal methods revealed denaturation profiles, distinction between single and double strandedness and the use of heteroduplexes-led to gene mapping of relatively simple systems carried out in close connection with other methods of molecular genetics.

Introduction to Cell Membranes at Molecular Resolution

1978 ◽  
Vol 36 (3) ◽  
pp. 497-502
Author(s):  
R.J. Barrnett
Keyword(s):  
Cell Membranes ◽  
International Federation ◽  
Mountain Range ◽  
Cellular Membranes ◽  
Short History ◽  
Biological Organization ◽  
Macromolecular Assemblies ◽  
The Past

This subject, is like observing the panorama of a mountain range, magnificent towering peaks, but it doesn't take much duration of observation to recognize that they are still in the process of formation. The mountains consist of approaches, materials and methods and the rocky substance of information has accumulated to such a degree that I find myself concentrating on the foothills in the foreground in order to keep up with the advance; the edifices behind form a wonderous, substantive background. It's a short history for such an accumulation and much of it has been moved by the members of the societies that make up this International Federation. My panel of speakers are here to provide what we hope is an interesting scientific fare, based on the fact that there is a continuum of biological organization from biochemical molecules through macromolecular assemblies and cellular membranes to the cell itself. Indeed, this fact explains the whole range of towering peaks that have emerged progressively during the past 25 years.

Characterization of microtubules by dark-field STEM and replication

1991 ◽  
Vol 49 ◽  
pp. 152-153
Author(s):  
S.B. Andrews ◽  
R.D. Leapman ◽  
P.E. Gallant ◽  
T.S. Reese
Keyword(s):  
Protein Interactions ◽  
Low Dose ◽  
Unit Length ◽  
Dark Field ◽  
Carbon Films ◽  
Microtubule Associated Proteins ◽  
Molecular Weights ◽  
Freeze Dried ◽  
Protein Motors ◽  
Associated Proteins

As part of a study on protein interactions involved in microtubule (MT)-based transport, we used the VG HB501 field-emission STEM to obtain low-dose dark-field mass maps of isolated, taxol-stabilized MTs and correlated these micrographs with detailed stereo images from replicas of the same MTs. This approach promises to be useful for determining how protein motors interact with MTs. MTs prepared from bovine and squid brain tubulin were purified and free from microtubule-associated proteins (MAPs). These MTs (0.1-1 mg/ml tubulin) were adsorbed to 3-nm evaporated carbon films supported over Formvar nets on 600-m copper grids. Following adsorption, the grids were washed twice in buffer and then in either distilled water or in isotonic or hypotonic ammonium acetate, blotted, and plunge-frozen in ethane/propane cryogen (ca. -185 C). After cryotransfer into the STEM, specimens were freeze-dried and recooled to ca.-160 C for low-dose (<3000 e/nm2) dark-field mapping. The molecular weights per unit length of MT were determined relative to tobacco mosaic virus standards from elastic scattering intensities. Parallel grids were freeze-dried and rotary shadowed with Pt/C at 14°.

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