Aptamers are specific nucleic acid sequences that can bind to a wide range of nucleic acid and non-nucleic acid targets with high affinity and specificity. Nucleic acid aptamers are selected in vitro from single stran...Aptamers are specific nucleic acid sequences that can bind to a wide range of nucleic acid and non-nucleic acid targets with high affinity and specificity. Nucleic acid aptamers are selected in vitro from single stranded DNA or RNA ligands containing random sequences of up to a few hundred nucleotides. Systematic evolution of ligands by exponential enrichment （SELEX） was used to select and PCR amplify DNA sequences （aptamers） capable of binding to and detecting Listeria monocytogenes, one of the major food-borne pathogens. A simplified affinity separation approach was employed, in which L. monocytogenes in exponential （log） phase of growth was used as the separation target. A fluorescently-labeled aptamer assay scheme was devised for detecting L. monoeytogenes. This report described a novel approach to the detection of L. monocytogenes using DNA aptamers. Aptamers were developed by nine rounds of SELEX. A high affinity aptamer was successfully selected from the initial random DNA pool, and its secondary structure was also investigated. One of aptamers named e01 with the highest affinity was further tested in aptamer-peroxidase and aptamer-fluorescence staining protocols. This study has proved the principle that the whole-cell SELEX could be a promising technique to design aptamer-based molecular probes for dectection of pathogenic microorganisms without tedious isolation and purification of complex markers or targets.展开更多
Aptamers are a class of single oligonucleotide molecules(DNA or RNA)that are screened from random DNA or RNA oligonucleotide chain libraries by the systemic evolution of ligands by exponential enrichment technology.Th...Aptamers are a class of single oligonucleotide molecules(DNA or RNA)that are screened from random DNA or RNA oligonucleotide chain libraries by the systemic evolution of ligands by exponential enrichment technology.The selected aptamers are capable of specifically binding to different targeting molecules,which is achieved by the three-dimensional structure of aptamers.Aptamers are similar in function to monoclonal antibodies,and therefore,they are also referred to as"chemical antibodies".Due to their high affinity and specificity and low immunogenicity,aptamers are topics of intense interest in today's biological targeting research especially in tumor research.They not only have high potential for clinical advances in tumor targeting detection but also are highly promising as targeted tumor drug carriers for use in tumor therapy.Various experimental studies have shown that aptamer-based diagnostic and therapeutic methods for liver cancer have great potential for application.This paper summarizes the structure,characteristics,and screening methods of aptamers and reviews the recent research progress on nucleic acid aptamers in the targeted diagnosis and treatment of liver cancer.展开更多
DNA核酶是通过指数富集配体的系统进化技术(Systematic Evolution of Ligands by Exponential Enrichment,SELEX)筛选出来的具有催化活性的DNA分子。本文重点综述了DNA核酶的分类、筛选及主要应用。根据其催化作用方式,可将DNA核酶分为...DNA核酶是通过指数富集配体的系统进化技术(Systematic Evolution of Ligands by Exponential Enrichment,SELEX)筛选出来的具有催化活性的DNA分子。本文重点综述了DNA核酶的分类、筛选及主要应用。根据其催化作用方式,可将DNA核酶分为切割类、连接类、磷酸化类和其他类,其中切割类和连接类占的比例较大。目前DNA核酶的底物主要还是以核酸居多。DNA核酶的筛选主要是采用生物素-链霉亲和素法和聚丙烯酰胺凝胶电泳法来分离有催化活性的DNA分子。目前DNA核酶在金属离子检测、基因治疗和DNA分子加密系统中都呈现出较好的应用前景。展开更多
文摘Aptamers are specific nucleic acid sequences that can bind to a wide range of nucleic acid and non-nucleic acid targets with high affinity and specificity. Nucleic acid aptamers are selected in vitro from single stranded DNA or RNA ligands containing random sequences of up to a few hundred nucleotides. Systematic evolution of ligands by exponential enrichment （SELEX） was used to select and PCR amplify DNA sequences （aptamers） capable of binding to and detecting Listeria monocytogenes, one of the major food-borne pathogens. A simplified affinity separation approach was employed, in which L. monocytogenes in exponential （log） phase of growth was used as the separation target. A fluorescently-labeled aptamer assay scheme was devised for detecting L. monoeytogenes. This report described a novel approach to the detection of L. monocytogenes using DNA aptamers. Aptamers were developed by nine rounds of SELEX. A high affinity aptamer was successfully selected from the initial random DNA pool, and its secondary structure was also investigated. One of aptamers named e01 with the highest affinity was further tested in aptamer-peroxidase and aptamer-fluorescence staining protocols. This study has proved the principle that the whole-cell SELEX could be a promising technique to design aptamer-based molecular probes for dectection of pathogenic microorganisms without tedious isolation and purification of complex markers or targets.
文摘Aptamers are a class of single oligonucleotide molecules(DNA or RNA)that are screened from random DNA or RNA oligonucleotide chain libraries by the systemic evolution of ligands by exponential enrichment technology.The selected aptamers are capable of specifically binding to different targeting molecules,which is achieved by the three-dimensional structure of aptamers.Aptamers are similar in function to monoclonal antibodies,and therefore,they are also referred to as"chemical antibodies".Due to their high affinity and specificity and low immunogenicity,aptamers are topics of intense interest in today's biological targeting research especially in tumor research.They not only have high potential for clinical advances in tumor targeting detection but also are highly promising as targeted tumor drug carriers for use in tumor therapy.Various experimental studies have shown that aptamer-based diagnostic and therapeutic methods for liver cancer have great potential for application.This paper summarizes the structure,characteristics,and screening methods of aptamers and reviews the recent research progress on nucleic acid aptamers in the targeted diagnosis and treatment of liver cancer.
基金National Mega Research Program of China(2008ZX10002-011)National Natural Science Foundation of China(30700701)National High Tech-nology Research and Development program of China(2006AA02Z128)
文摘DNA核酶是通过指数富集配体的系统进化技术(Systematic Evolution of Ligands by Exponential Enrichment,SELEX)筛选出来的具有催化活性的DNA分子。本文重点综述了DNA核酶的分类、筛选及主要应用。根据其催化作用方式,可将DNA核酶分为切割类、连接类、磷酸化类和其他类,其中切割类和连接类占的比例较大。目前DNA核酶的底物主要还是以核酸居多。DNA核酶的筛选主要是采用生物素-链霉亲和素法和聚丙烯酰胺凝胶电泳法来分离有催化活性的DNA分子。目前DNA核酶在金属离子检测、基因治疗和DNA分子加密系统中都呈现出较好的应用前景。
