The Experts below are selected from a list of 4314 Experts worldwide ranked by ideXlab platform
Lianhui Wang - One of the best experts on this subject based on the ideXlab platform.
-
Ultrasensitive SERS determination of avian influenza A H7N9 virus via Exonuclease III-assisted cycling amplification.
Talanta, 2019Co-Authors: Chunyuan Song, Liu Yang, Xinyu Jiang, Jingjing Zhang, Chen Dong, Lianhui WangAbstract:Abstract The avian influenza A H7N9 virus is known as one of the newly discovered highly pathogenic avian influenzas with serious threat to public health and the poultry industry. In this work, an ultrasensitive surface-enhanced Raman scattering (SERS) determination of H7N9 virus via Exonuclease III-assisted cycling amplification was proposed to meet the needs of rapid, sensitive and accurate detection of H7N9-related genes. The SERS strategy aims to simultaneously determine the characteristic gene fragments of H7 and N9 by specially designing Capture, Replace, and Probe single-strand DNAs to realize Exonuclease III-assisted cycling amplifications, and then integrating the cyclic amplification with SERS-active Ag nanorods array substrate to achieve an ultrasensitive SERS determination of H7N9. After characterizing the effectiveness of the sensing mechanism and further investigating the surface blocking and the dosage of Exonuclease III, the optimal surface blocking was achieved by using 10 μM and 100 μM mercaptohexanol for H7 and N9 detection respectively, and the optimal Exo III concentrations for sensing H7 and N9 were 0.10 U μL−1 and 0.30 U μL−1 respectively. Under the optimal conditions, dual and specific detections of H7 and N9 gene fragments were obtained with detection linear interval from 1 fM to 100 pM and limit of detections low to 31 aM of H7 and 44 aM of N9, as well as recovery in the range of 93.8–106.2% with relative standard deviation less than 6.12%. The proposed ultrasensitive SERS strategy can provide a powerful tool for determining H7N9 virus and other avian influenza viruses.
-
an Exonuclease III powered on particle stochastic dna walker
Angewandte Chemie, 2017Co-Authors: Xiaolei Zuo, Dan Zhu, Guangbao Yao, Jie Chao, Huajie Liu, Lihua Wang, Jiye Shi, Lianhui WangAbstract:DNA-based machines have attracted rapidly growing interest owing to their potential in drug delivery, biocomputing, and diagnostic applications. Herein, we report a type of Exonuclease III (Exo III)-powered stochastic DNA walker that can autonomously move on a spherical nucleic acid (SNA)-based 3D track. The motion is propelled by unidirectional Exo III digestion of hybridized DNA tracks in a burnt-bridge mechanism. The operation of this Exo III-propelled DNA walker was monitored in real time and at the single-particle resolution using total internal reflection fluorescence microscopy (TIRF). We further interrogated the morphological effect of the 3D track on the nuclease activity, which suggested that the performance of the DNA walker was critically dependent upon the DNA density and the track conformation. Finally, we demonstrated potential bioanalytical applications of this SNA-based stochastic DNA walker by exploiting movement-triggered cascade signal amplification.
-
An Exonuclease III‐Powered, On‐Particle Stochastic DNA Walker
Angewandte Chemie (International ed. in English), 2017Co-Authors: Dan Zhu, Xiaolei Zuo, Guangbao Yao, Jie Chao, Huajie Liu, Lihua Wang, Jiye Shi, Lianhui WangAbstract:DNA-based machines have attracted rapidly growing interest owing to their potential in drug delivery, biocomputing, and diagnostic applications. Herein, we report a type of Exonuclease III (Exo III)-powered stochastic DNA walker that can autonomously move on a spherical nucleic acid (SNA)-based 3D track. The motion is propelled by unidirectional Exo III digestion of hybridized DNA tracks in a burnt-bridge mechanism. The operation of this Exo III-propelled DNA walker was monitored in real time and at the single-particle resolution using total internal reflection fluorescence microscopy (TIRF). We further interrogated the morphological effect of the 3D track on the nuclease activity, which suggested that the performance of the DNA walker was critically dependent upon the DNA density and the track conformation. Finally, we demonstrated potential bioanalytical applications of this SNA-based stochastic DNA walker by exploiting movement-triggered cascade signal amplification.
Carlos Frederico Martins Menck - One of the best experts on this subject based on the ideXlab platform.
-
Mutation spectrum induced by singlet oxygen in Escherichia coli deficient in Exonuclease III.
Photochemistry and photobiology, 1999Co-Authors: Lucymara Fassarella Agnez-lima, Paolo Di Mascio, Rita L. Napolitano, Robert P. P. Fuchs, Carlos Frederico Martins MenckAbstract:The repair of singlet oxygen (1O2)-induced DNA lesions requires several enzymes of the nucleotide and base excision repair pathways, including Exonuclease III and endonuclease IV that are known apurinic/apyrimidinic-endonucleases in Escherichia coli. In order to better understand the relevance of Exonuclease III on the repair of these lesions, we investigated the mutagenic events that result from the replication of a 1O2-damaged plasmid in an Exonuclease-deficient host (xth). The mutation spectrum in the tRNA supF gene target indicated that the absence of Exonuclease III does not change the types of mutations induced by 1O2 (mostly of G:C-->T:A and G:C-->C:G transversions). However, the spectrum shows that the mutations are scattered in the supF gene, which is significatively different from the one obtained in wild-type bacteria. Thus, Exonuclease III may act on the repair of 1O2-induced lesions altering the DNA repair sequence specificity.
-
Involvement of Escherichia coli Exonuclease III and endonuclease IV in the repair of singlet oxygen-induced DNA damage
Carcinogenesis, 1996Co-Authors: Lucymara F. Agnez, Paolo Di Mascio, Regina Costa De Oliveira, Carlos Frederico Martins MenckAbstract:Singlet molecular oxygen ( 1 O 2 ) has been implicated in several biological processes that may lead to genetic damage. The relevance of various repair pathways in plasmid inactivation mediated by 1 O 2 was investigated. Plasmid treated with 1 O 2 , chemically generated, was transfected into Escherichia coli strains deficient in genes implicated in the DNA repair of oxidative damage. The ability to transform bacteria is significantly reduced in the double mutant xth,nfo, deficient in both Exonuclease III and endonuclease IV, although it was similar to wild-type cells in single mutants. The products of these two genes are able to cleave DNA damaged by 1 O 2 and to remove DNA polymerization blocks from 3'-termini generated either directly by 1 O 2 treatment or after the action of the formamidopyrimidine-DNA-N-glycosylase (Fpg protein). The results indicate that the Exonuclease III and endonuclease IV participate in the excision of lethal lesions induced in DNA by 1 O 2 .
Ian D. Hickson - One of the best experts on this subject based on the ideXlab platform.
-
Isolation of cDNA clones encoding a human apurinic/apyrimidinic endonuclease that corrects DNA repair and mutagenesis defects in E. coli xth (Exonuclease III) mutants.
Nucleic acids research, 1991Co-Authors: Craig N. Robson, Ian D. HicksonAbstract:Apurinic/apyrimidinic (AP) sites in cellular DNA are considered to be both cytotoxic and mutagenic, and can arise spontaneously or following exposure to DNA damaging agents. We have isolated cDNA clones which encode an endonuclease, designated HAP1 (human AP endonuclease 1), that catalyses the initial step in AP site repair in human cells. The predicted HAP1 protein has an Mr of 35,500 and shows striking sequence similarity (93% identity) to BAP 1, a bovine AP endonuclease enzyme. Significant sequence homology to two bacterial DNA repair enzymes, E. coli Exonuclease III and S. pneumoniae ExoA proteins, and to Drosophila Rrp1 protein is also apparent. We have expressed the HAP1 cDNA in E. coli mutants lacking Exonuclease III (xth), endonuclease IV (nfo), or both AP endonucleases. The HAP1 protein can substitute for Exonuclease III, but not for endonuclease IV, in respect of some, but not all, DNA repair and mutagenesis functions. Moreover, a dut xth (ts) double mutant, which is nonviable at 42 degrees C due to an accumulation of unrepaired AP sites following excision of uracil from DNA, was rescued by expression of the HAP1 cDNA. These results indicate that AP endonucleases show remarkable conservation of both primary sequence and function. We would predict that the HAP1 protein is important in human cells for protection against the toxic and mutagenic effects of DNA damaging agents.
-
isolation of cdna clones encoding a human apurinic apyrimidinic endonuclease that corrects dna repair and mutagenesis defects in e coli xth Exonuclease III mutants
Nucleic Acids Research, 1991Co-Authors: Craig N. Robson, Ian D. HicksonAbstract:Apurinic/apyrimidinic (AP) sites in cellular DNA are considered to be both cytotoxic and mutagenic, and can arise spontaneously or following exposure to DNA damaging agents. We have isolated cDNA clones which encode an endonuclease, designated HAP1 (human AP endonuclease 1), that catalyses the initial step in AP site repair in human cells. The predicted HAP1 protein has an Mr of 35,500 and shows striking sequence similarity (93% identity) to BAP 1, a bovine AP endonuclease enzyme. Significant sequence homology to two bacterial DNA repair enzymes, E. coli Exonuclease III and S. pneumoniae ExoA proteins, and to Drosophila Rrp1 protein is also apparent. We have expressed the HAP1 cDNA in E. coli mutants lacking Exonuclease III (xth), endonuclease IV (nfo), or both AP endonucleases. The HAP1 protein can substitute for Exonuclease III, but not for endonuclease IV, in respect of some, but not all, DNA repair and mutagenesis functions. Moreover, a dut xth (ts) double mutant, which is nonviable at 42 degrees C due to an accumulation of unrepaired AP sites following excision of uracil from DNA, was rescued by expression of the HAP1 cDNA. These results indicate that AP endonucleases show remarkable conservation of both primary sequence and function. We would predict that the HAP1 protein is important in human cells for protection against the toxic and mutagenic effects of DNA damaging agents.
Dan Zhu - One of the best experts on this subject based on the ideXlab platform.
-
an Exonuclease III powered on particle stochastic dna walker
Angewandte Chemie, 2017Co-Authors: Xiaolei Zuo, Dan Zhu, Guangbao Yao, Jie Chao, Huajie Liu, Lihua Wang, Jiye Shi, Lianhui WangAbstract:DNA-based machines have attracted rapidly growing interest owing to their potential in drug delivery, biocomputing, and diagnostic applications. Herein, we report a type of Exonuclease III (Exo III)-powered stochastic DNA walker that can autonomously move on a spherical nucleic acid (SNA)-based 3D track. The motion is propelled by unidirectional Exo III digestion of hybridized DNA tracks in a burnt-bridge mechanism. The operation of this Exo III-propelled DNA walker was monitored in real time and at the single-particle resolution using total internal reflection fluorescence microscopy (TIRF). We further interrogated the morphological effect of the 3D track on the nuclease activity, which suggested that the performance of the DNA walker was critically dependent upon the DNA density and the track conformation. Finally, we demonstrated potential bioanalytical applications of this SNA-based stochastic DNA walker by exploiting movement-triggered cascade signal amplification.
-
An Exonuclease III‐Powered, On‐Particle Stochastic DNA Walker
Angewandte Chemie (International ed. in English), 2017Co-Authors: Dan Zhu, Xiaolei Zuo, Guangbao Yao, Jie Chao, Huajie Liu, Lihua Wang, Jiye Shi, Lianhui WangAbstract:DNA-based machines have attracted rapidly growing interest owing to their potential in drug delivery, biocomputing, and diagnostic applications. Herein, we report a type of Exonuclease III (Exo III)-powered stochastic DNA walker that can autonomously move on a spherical nucleic acid (SNA)-based 3D track. The motion is propelled by unidirectional Exo III digestion of hybridized DNA tracks in a burnt-bridge mechanism. The operation of this Exo III-propelled DNA walker was monitored in real time and at the single-particle resolution using total internal reflection fluorescence microscopy (TIRF). We further interrogated the morphological effect of the 3D track on the nuclease activity, which suggested that the performance of the DNA walker was critically dependent upon the DNA density and the track conformation. Finally, we demonstrated potential bioanalytical applications of this SNA-based stochastic DNA walker by exploiting movement-triggered cascade signal amplification.
Zeng-ping Chen - One of the best experts on this subject based on the ideXlab platform.
-
Detection of microRNAs by the combination of Exonuclease-III assisted target recycling amplification and repeated-fishing strategy.
Analytica chimica acta, 2020Co-Authors: Xiao-mei Yan, Yin-qi Wang, Yao Chen, Zeng-ping ChenAbstract:Abstract A simple but effective method for the detection of miRNAs was proposed by integrating Exonuclease-III assisted target recycling amplification and repeated-fishing strategy. In the proposed method, Exonuclease-III assisted target recycling amplification reaction is adopted to produce a large amount of DNA fragments with fluorescence group at its 5′ end in the presence of the target miRNA, which are then repeatedly fished out from the reaction mixture by a gold foil modified with a capture probe and transferred into a so-called ‘product tube’. The amount of the target miRNA can then be determined from the fluorescence measurement of the solution in the ‘product tube’. Application to the detection of miRNA-155 in samples of KH-2 and BRSA-2B cells revealed that the proposed method could achieve sensitive and accurate quantification of the target miRNA with a limit of detection of 36 fM and recovery rates in the range from 96.2% to 105%. Its simplicity, sensitivity and resistance to possible fluorescence interferences in complex biological samples make the proposed method a potentially competitive alternative for miRNAs detection in complex biological samples.
-
An advanced model for the detection of short DNA sequences by mass spectrometry based on Exonuclease III assisted recycling amplification
Chemometrics and Intelligent Laboratory Systems, 2018Co-Authors: Cai-xia Shi, Qing Liu, Zeng-ping ChenAbstract:Abstract Exonuclease III assisted target recycling amplification strategy can be used to enhance the sensitivity of mass spectrometry for the detection of short DNA sequences. However, the distribution pattern of DNA fragments produced by Exonuclease III assisted target recycling amplification is generally different for samples with different concentrations of the target DNA sequence, which hinders the extraction of both qualitative and quantitative information of the target DNA from mass spectral measurements using traditional univariate or multivariate models. In this contribution, an advanced model was derived based on a reasonable assumption for the qualitative and quantitative analysis of the mass spectral measurements of DNA fragments produced by Exonuclease III-assisted target recycling amplification. Experimental results demonstrated that the integration of Exonuclease III assisted target recycling amplification, mass spectrometry and the advanced model could achieve sensitive and accurate quantitative results for a target short DNA sequence in complex biological medium with a detection limit of 50 pM and a mean recovery rate within the range of 89.5%–106.7%. More interestingly, the proposed model could unambiguously identify single nucleotide polymorphisms based on the distribution patterns of residual DNA fragments. Therefore, with the aid of the proposed model, mass spectrometry based on Exonuclease III assisted recycling amplification has great potential for the reliable, sensitive, selective, and relatively low-cost detection and quantification of short DNA sequences in clinical diagnosis and biomedical research.