Influence of Nanochannel Inlet Structure Upon DNA Capture Ratio

2011 ◽  
Author(s):  
Jiahao Wu ◽  
Hong Wang ◽  
Jinsoo Kim ◽  
Freddy Murphy ◽  
Steven A. Soper ◽  
...  
Keyword(s):  
Real Time ◽  
Persistence Length ◽  
Contour Length ◽  
Dna Molecules ◽  
Channel Diameter ◽  
Dna Molecule ◽  
Capture Ratio ◽  
Sequence Variations ◽  
Dna Capture ◽  
Dna Chain

DNA molecule will be stretched to its near full contour length inside a nanochannel when the channel diameter is less than the DNA persistence length.1–3 It provides the possibility of real time lab-free-analysis of analysis, such as screening of sequence variations of DNA molecules.3 The key process for this nanochannel-based analysis is to drive DNA molecule electrophoretically through the nanochannel and read out the information of the DNA chain while it is passing the channel.2, 3

scholarly journals Nanochannel-Confined TAMRA-Polypyrrole Stained DNA Stretching by Varying the Ionic Strength from Micromolar to Millimolar Concentrations

Polymers ◽  
2018 ◽  
Vol 11 (1) ◽  
pp. 15 ◽  
Author(s):  
Seonghyun Lee ◽  
Yelin Lee ◽  
Yongkyun Kim ◽  
Cong Wang ◽  
Jungyul Park ◽  
...  
Keyword(s):  
Ionic Strength ◽  
Double Helix ◽  
Persistence Length ◽  
Polymer Physics ◽  
Structural Deformation ◽  
Contour Length ◽  
Dna Molecules ◽  
Dna Stretching ◽  
Single Dna Molecules ◽  
Length Changes

Large DNA molecules have been utilized as a model system to investigate polymer physics. However, DNA visualization via intercalating dyes has generated equivocal results due to dye-induced structural deformation, particularly unwanted unwinding of the double helix. Thus, the contour length increases and the persistence length changes so unpredictably that there has been a controversy. In this paper, we used TAMRA-polypyrrole to stain single DNA molecules. Since this staining did not change the contour length of B-form DNA, we utilized TAMRA-polypyrrole stained DNA as a tool to measure the persistence length by changing the ionic strength. Then, we investigated DNA stretching in nanochannels by varying the ionic strength from 0.06 mM to 47 mM to evaluate several polymer physics theories proposed by Odijk, de Gennes and recent papers to deal with these regimes.

scholarly journals Revealing in real-time a multistep assembly mechanism for SV40 virus-like particles

2020 ◽  
Vol 6 (16) ◽  
pp. eaaz1639 ◽  
Author(s):  
Mariska G. M. van Rosmalen ◽  
Douwe Kamsma ◽  
Andreas S. Biebricher ◽  
Chenglei Li ◽  
Adam Zlotnick ◽  
...  
Keyword(s):  
Real Time ◽  
Optical Tweezers ◽  
Self Assembly ◽  
Persistence Length ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
Contour Length ◽  
Sv40 Virus ◽  
Virus Like Particles ◽  
Assembly Mechanism

Many viruses use their genome as template for self-assembly into an infectious particle. However, this reaction remains elusive because of the transient nature of intermediate structures. To elucidate this process, optical tweezers and acoustic force spectroscopy are used to follow viral assembly in real time. Using Simian virus 40 (SV40) virus-like particles as model system, we reveal a multistep assembly mechanism. Initially, binding of VP1 pentamers to DNA leads to a significantly decreased persistence length. Moreover, the pentamers seem able to stabilize DNA loops. Next, formation of interpentamer interactions results in intermediate structures with reduced contour length. These structures stabilize into objects that permanently decrease the contour length to a degree consistent with DNA compaction in wild-type SV40. These data indicate that a multistep mechanism leads to fully assembled cross-linked SV40 particles. SV40 is studied as drug delivery system. Our insights can help optimize packaging of therapeutic agents in these particles.

Existence of DNA in yeast microbodies

1978 ◽  
Vol 36 (2) ◽  
pp. 232-233
Author(s):  
Masako Osumi ◽  
Misuzu Nagano ◽  
Hiroko Kazama
Keyword(s):  
Catalase Activity ◽  
Buoyant Density ◽  
Model System ◽  
Contour Length ◽  
Native State ◽  
Normal Alkane ◽  
Remarkable Increase ◽  
Dna Molecule ◽  
Mitochondrial Dnas

We have found that microbodies appeared profusely together with a remarkable increase in catalase activity in normal alkane-grown cells of hydrocarbon-utilizing Candida yeasts, and that the microbodies multiplied by division in these cells. These features of Candida yeasts seem to provide a useful model system for studies on the biogenesis of the microbody. Subsequently, we have succeeded in isolation of Candida microbodies in an apparently native state, as judged biochemically and morphologically. The presence of DNA in the purified microbody fraction thus obtained was proved by the diphenylamine method. DNA molecule of about 15 urn in contour length was released from an isolated microbody. The physicochemical analyses of the microbody DNA revealed that its buoyant density differed from nuclear and mitochondrial DNAs. All these results lead us to the possibility that there is a novel type of DNA in microbodies.

scholarly journals Species identification of Anguilla japonica by real-time PCR based on a sequence detection system: a practical application to eggs and larvae

2009 ◽  
Vol 66 (9) ◽  
pp. 1915-1918 ◽  
Author(s):  
Yuki Minegishi ◽  
Tatsuki Yoshinaga ◽  
Jun Aoyama ◽  
Katsumi Tsukamoto
Keyword(s):  
Real Time ◽  
Species Identification ◽  
Developmental Stages ◽  
Detection System ◽  
Anguilla Japonica ◽  
Sequence Detection ◽  
Target Region ◽  
System A ◽  
Sequence Variations ◽  
Eggs And Larvae

Abstract Minegishi, Y., Yoshinaga, T., Aoyama, J., and Tsukamoto, K. 2009. Species identification of Anguilla japonica by real-time PCR based on a sequence detection system: a practical application to eggs and larvae. – ICES Journal of Marine Science, 66: 1915–1918. To develop a practical method for identifying Japanese eel Anguilla japonica eggs and larvae to species by a sequence detection system using a real-time polymerase chain reaction (PCR), we examined (i) the sensitivity of the system using samples at various developmental stages, and (ii) influences of intra- and interspecific DNA sequence variations in the PCR target region. PCR amplifications with extracted DNA solution at 7.0 ng µl−1 or lower were efficient at distinguishing A. japonica from other anguillids. A single egg at the gastrula or later developmental stages could also be identified. Two sequence variations in the PCR target region were observed in 2 out of 35 A. japonica collected from three localities, and from four year classes at a single locality. These mutations, however, did not affect the result of species identification achieved by A. japonica-specific PCR primers and probe. The accuracy of this PCR-based method of species identification will help in field surveys of the species.

scholarly journals Replication forms of the gene-sized DNA molecules of hypotrichous ciliates.

1983 ◽  
Vol 3 (9) ◽  
pp. 1562-1566 ◽  
Author(s):  
K G Murti ◽  
D M Prescott
Keyword(s):  
Electron Microscopy ◽  
S Phase ◽  
Origin Of Replication ◽  
Dna Molecules ◽  
Linear Dna ◽  
Dna Molecule ◽  
Independent Unit

Using a method for obtaining DNA from 10 to 40 macronuclei for electron microscopy, we analyzed the structure of gene-sized, linear DNA molecules from S-phase macronuclei of two hypotrichous ciliates, Euplotes eurystomus and Styx sp. Three types of putative replicating intermediates were observed: (i) molecules with a bubble close to one end, (ii) molecules with single forks, and (iii) molecules with two forks. We conclude that: (i) each macronuclear DNA molecule replicates as an independent unit, (ii) the molecules contain an origin of replication close to one or both ends, and (iii) the mode of replication is bidirectional.

scholarly journals Assembly, translocation, and activation of XerCD-difrecombination by FtsK translocase analyzed in real-time by FRET and two-color tethered fluorophore motion

2015 ◽  
Vol 112 (37) ◽  
pp. E5133-E5141 ◽  
Author(s):  
Peter F. J. May ◽  
Pawel Zawadzki ◽  
David J. Sherratt ◽  
Achillefs N. Kapanidis ◽  
Lidia K. Arciszewska
Keyword(s):  
Real Time ◽  
Bacterial Chromosome ◽  
Dna Loops ◽  
Synaptic Complex ◽  
Dna Molecule ◽  
Subsequent Activation ◽  
Replication Terminus

The FtsK dsDNA translocase functions in bacterial chromosome unlinking by activating XerCD-difrecombination in the replication terminus region. To analyze FtsK assembly and translocation, and the subsequent activation of XerCD-difrecombination, we extended the tethered fluorophore motion technique, using two spectrally distinct fluorophores to monitor two effective lengths along the same tethered DNA molecule. We observed that FtsK assembled stepwise on DNA into a single hexamer, and began translocation rapidly (∼0.25 s). Without extruding DNA loops, single FtsK hexamers approached XerCD-difand resided there for ∼0.5 s irrespective of whether XerCD-difwas synapsed or unsynapsed. FtsK then dissociated, rather than reversing. Infrequently, FtsK activated XerCD-difrecombination when it encountered a preformed synaptic complex, and dissociated before the completion of recombination, consistent with each FtsK–XerCD-difencounter activating only one round of recombination.

scholarly journals Real-time imaging of single DNA molecules with fluorescence microscopy

1989 ◽  
Vol 56 (3) ◽  
pp. 507-516 ◽  
Author(s):  
T.W. Houseal ◽  
C. Bustamante ◽  
R.F. Stump ◽  
M.F. Maestre
Keyword(s):  
Fluorescence Microscopy ◽  
Real Time ◽  
Dna Molecules ◽  
Real Time Imaging ◽  
Single Dna Molecules

DNA Base Identification by Electron Microscopy

2012 ◽  
Vol 18 (5) ◽  
pp. 1049-1053 ◽  
Author(s):  
David C. Bell ◽  
W. Kelley Thomas ◽  
Katelyn M. Murtagh ◽  
Cheryl A. Dionne ◽  
Adam C. Graham ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Base Pair ◽  
Heavy Atom ◽  
Genomic Research ◽  
Biological Research ◽  
Template Molecule ◽  
Dna Molecules ◽  
Base Pairs ◽  
Dna Molecule ◽  
Dna Base

AbstractAdvances in DNA sequencing, based on fluorescent microscopy, have transformed many areas of biological research. However, only relatively short molecules can be sequenced by these technologies. Dramatic improvements in genomic research will require accurate sequencing of long (>10,000 base-pairs), intact DNA molecules. Our approach directly visualizes the sequence of DNA molecules using electron microscopy. This report represents the first identification of DNA base pairs within intact DNA molecules by electron microscopy. By enzymatically incorporating modified bases, which contain atoms of increased atomic number, direct visualization and identification of individually labeled bases within a synthetic 3,272 base-pair DNA molecule and a 7,249 base-pair viral genome have been accomplished. This proof of principle is made possible by the use of a dUTP nucleotide, substituted with a single mercury atom attached to the nitrogenous base. One of these contrast-enhanced, heavy-atom-labeled bases is paired with each adenosine base in the template molecule and then built into a double-stranded DNA molecule by a template-directed DNA polymerase enzyme. This modification is small enough to allow very long molecules with labels at each A-U position. Image contrast is further enhanced by using annular dark-field scanning transmission electron microscopy (ADF-STEM). Further refinements to identify additional base types and more precisely determine the location of identified bases would allow full sequencing of long, intact DNA molecules, significantly improving the pace of complex genomic discoveries.

Persistence length of DNA molecules confined in nanochannels

2010 ◽  
Vol 12 (31) ◽  
pp. 8934 ◽  
Author(s):  
Peter Cifra ◽  
Zuzana Benková ◽  
Tomáš Bleha
Keyword(s):  
Persistence Length ◽  
Dna Molecules
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