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
Metallothioneins(MTs) are normally considered to be sensitive indicators of heavy metal pollution, but it is less clear whether the MT gene can actively respond to other environmental stresses. In this study, an MT m ...Metallothioneins(MTs) are normally considered to be sensitive indicators of heavy metal pollution, but it is less clear whether the MT gene can actively respond to other environmental stresses. In this study, an MT m RNA molecular sequence of 471 bp(full length) was identified in marine cultured black porgy(Acanthopagrus schlegelii), encoding 60 amino acids containing 20 cysteine residues. The MT sequence was highly homologous to that of other fish belonging to the MT superfamily type 1 family. The three dimensional structure of the deduced MT peptide was composed of two metal-binding domains capable of ligating divalent heavy metals. The MT m RNA transcripts were detected in the 11 tested tissues and the highest quantity was present in the liver. Stresses by two factors, benzo[a]pyrene(B[a]p) exposure and bacterial challenge, were evaluated on MT gene expression. The level of MT gene transcripts in the liver significantly declined 24 h post B[a]p exposure and the quantity was significantly correlated with the exposure time during a 24 h period. In contrast, MT gene expression in the liver was significantly increased 48 h post bacterial infection and the quantity was significantly correlated with the infection time during this period of 48 h. Our results indicated that MT gene expression in black porgy liver was sensitive to environmental stresses other than just the heavy metal pollution reported, suggesting that the development of a reliable biomarker for heavy metal pollution will be more complex than expected.展开更多
Since China’s Reform and Opening-up,the innovation and development of refractories for ironmaking industry in Sinosteel Luonai were narrated,including silica materials,Al_(2)O_(3)-SiO_(2) refractories and non-oxide c...Since China’s Reform and Opening-up,the innovation and development of refractories for ironmaking industry in Sinosteel Luonai were narrated,including silica materials,Al_(2)O_(3)-SiO_(2) refractories and non-oxide composites;and the development direction of refractories for ironmaking industry was prospected.展开更多
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。
基金sponsored by the National Natural Science Foundation of China (grant No.31100376)the Shanghai Municipal Education Commission (grant No.14YZ001)the MEL Visiting Fellowship Program
文摘Metallothioneins(MTs) are normally considered to be sensitive indicators of heavy metal pollution, but it is less clear whether the MT gene can actively respond to other environmental stresses. In this study, an MT m RNA molecular sequence of 471 bp(full length) was identified in marine cultured black porgy(Acanthopagrus schlegelii), encoding 60 amino acids containing 20 cysteine residues. The MT sequence was highly homologous to that of other fish belonging to the MT superfamily type 1 family. The three dimensional structure of the deduced MT peptide was composed of two metal-binding domains capable of ligating divalent heavy metals. The MT m RNA transcripts were detected in the 11 tested tissues and the highest quantity was present in the liver. Stresses by two factors, benzo[a]pyrene(B[a]p) exposure and bacterial challenge, were evaluated on MT gene expression. The level of MT gene transcripts in the liver significantly declined 24 h post B[a]p exposure and the quantity was significantly correlated with the exposure time during a 24 h period. In contrast, MT gene expression in the liver was significantly increased 48 h post bacterial infection and the quantity was significantly correlated with the infection time during this period of 48 h. Our results indicated that MT gene expression in black porgy liver was sensitive to environmental stresses other than just the heavy metal pollution reported, suggesting that the development of a reliable biomarker for heavy metal pollution will be more complex than expected.
文摘Since China’s Reform and Opening-up,the innovation and development of refractories for ironmaking industry in Sinosteel Luonai were narrated,including silica materials,Al_(2)O_(3)-SiO_(2) refractories and non-oxide composites;and the development direction of refractories for ironmaking industry was prospected.
