Label-Free Fluorescent Determination of Simian Virus 40 Using Triplex DNA and G-Quadruplex/N-Methyl Mesoporphyrin IX

We have developed a method which allows determination of the direction in which replication forks move through segments of chromosomal DNA for which cloned probes are available. The method is based on the facts that DNA restriction fragments containing replication forks migrate more slowly through agarose gels than do non-fork-containing fragments and that the extent of retardation of the fork-containing fragments is a function of the extent of replication. The procedure allows the identification of DNA replication origins as sites from which replication forks diverge. In this paper we demonstrate the feasibility of this procedure, with simian virus 40 DNA as a model, and we discuss its applicability to other systems.

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Correction: Determination of the Number of Superhelical Turns in Simian Virus 40 DNA by Gel Electrophoresis

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.73.7.2527-e ◽

1976 ◽

Vol 73 (7) ◽

pp. 2527-2527

Keyword(s):

Gel Electrophoresis ◽

Simian Virus 40 ◽

Simian Virus

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DNA sequence of the leftward junction in the adenovirus-simian virus 40 hybrid Ad2+D2 and determination of the structure of the D2-T antigen.

Journal of Virology ◽

10.1128/jvi.54.3.882-885.1985 ◽

1985 ◽

Vol 54 (3) ◽

pp. 882-885 ◽

Cited By ~ 5

Author(s):

E A Baumann ◽

C P Baur ◽

M Baack ◽

S Beck

Keyword(s):

Dna Sequence ◽

Simian Virus 40 ◽

Simian Virus ◽

T Antigen

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An Enzyme- and Label-Free Fluorescence Aptasensor for Detection of Thrombin Based on Graphene Oxide and G-Quadruplex

Sensors ◽

10.3390/s19204424 ◽

2019 ◽

Vol 19 (20) ◽

pp. 4424 ◽

Cited By ~ 2

Author(s):

Yani Wei ◽

Luhui Wang ◽

Yingying Zhang ◽

Yafei Dong

Keyword(s):

Graphene Oxide ◽

Cost Effective ◽

Target Pair ◽

Label Free ◽

Detection Scheme ◽

G Quadruplex ◽

Universal Detection ◽

Dna Strand ◽

Aptamer Sequence

An enzyme- and label-free aptamer-based assay is described for the determination of thrombin. A DNA strand (S) consisting of two parts was designed, where the first (Sa) is the thrombin-binding aptamer and the second (Se) is a G-quadruplex. In the absence of thrombin, Sa is readily adsorbed by graphene oxide (GO), which has a preference for ss-DNA rather than for ds-DNA. Upon the addition of the N-methyl-mesoporphyrin IX (NMM), its fluorescence (with excitation/emission at 399/610 nm) is quenched by GO. In contrast, in the presence of thrombin, the aptamer will bind thrombin, and thus, be separated from GO. As a result, fluorescence will be enhanced. The increase is linear in the 0.37 µM to 50 µM thrombin concentration range, and the detection limit is 0.37 nM. The method is highly selective over other proteins, cost-effective, and simple. In our perception, it represents a universal detection scheme that may be applied to other targets according to the proper choice of the aptamer sequence and formation of a suitable aptamer-target pair.

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