Ever since the low energy N + ion beam has been accepted, the mutations of ionizing radiation are attributable mainly to avoidance of DNA damages repair. Evidences based on in vivo proof results are limited. Using the...Ever since the low energy N + ion beam has been accepted, the mutations of ionizing radiation are attributable mainly to avoidance of DNA damages repair. Evidences based on in vivo proof results are limited. Using the E.coli wild type and mutator strains, the mutant frequencies suggest that base substitutions in rpoB gene are induced by the N + implantation. A highly conserved region is selected to get the direct evidence for base substitutions by sequence of the high fidelity PCR amplification products in mutants. Most of the mutants (90.9%, 40/44) have at least one base substitution in the amplification region. The evidences for CG to TA (55%, 22/40), AT to GC (20%, 8/40) and TA to CG (5%, 2/40) transitions are identified. The transversions are AT to TA (15%, 6/40) and GC to CG (5%, 2/40). It is suggested that DNA cytosine methylase might play an important role in mismatch repair of DNA damage induced by N + implantation by analysis of the mutant frequencies of mutator strains.展开更多
为了进一步理解低能N+注入在沙漠寡营养细菌(DOB)系统发育与进化中的作用,本研究基于DOB基因组De novo测序数据,应用生物信息学方法对3株离子束重组菌株DOB073、DOB113和DOB981的16S r RNA基因的突变与进化进行了分析。分析表明,3株离...为了进一步理解低能N+注入在沙漠寡营养细菌(DOB)系统发育与进化中的作用,本研究基于DOB基因组De novo测序数据,应用生物信息学方法对3株离子束重组菌株DOB073、DOB113和DOB981的16S r RNA基因的突变与进化进行了分析。分析表明,3株离子束重组DOB的16S r RNA基因拷贝数均比原始菌株增加了5个,并分别在C1区、V1区、V2区、V4区、V6区、V7区和V9区发生了碱基突变。进化分析显示DOB981的进化速度快于DOB073和DOB113。16S r RNA的保守二级结构预测表明,9个保守二级结构所处碱基位置分别为:80~120、120~240、240~360、360~480、400~520、640~760、760~880、800~920和1 420~1 540。本研究为低能离子注入介导的原核微生物进化提供了直接的分子证据。展开更多
文摘Ever since the low energy N + ion beam has been accepted, the mutations of ionizing radiation are attributable mainly to avoidance of DNA damages repair. Evidences based on in vivo proof results are limited. Using the E.coli wild type and mutator strains, the mutant frequencies suggest that base substitutions in rpoB gene are induced by the N + implantation. A highly conserved region is selected to get the direct evidence for base substitutions by sequence of the high fidelity PCR amplification products in mutants. Most of the mutants (90.9%, 40/44) have at least one base substitution in the amplification region. The evidences for CG to TA (55%, 22/40), AT to GC (20%, 8/40) and TA to CG (5%, 2/40) transitions are identified. The transversions are AT to TA (15%, 6/40) and GC to CG (5%, 2/40). It is suggested that DNA cytosine methylase might play an important role in mismatch repair of DNA damage induced by N + implantation by analysis of the mutant frequencies of mutator strains.
文摘为了进一步理解低能N+注入在沙漠寡营养细菌(DOB)系统发育与进化中的作用,本研究基于DOB基因组De novo测序数据,应用生物信息学方法对3株离子束重组菌株DOB073、DOB113和DOB981的16S r RNA基因的突变与进化进行了分析。分析表明,3株离子束重组DOB的16S r RNA基因拷贝数均比原始菌株增加了5个,并分别在C1区、V1区、V2区、V4区、V6区、V7区和V9区发生了碱基突变。进化分析显示DOB981的进化速度快于DOB073和DOB113。16S r RNA的保守二级结构预测表明,9个保守二级结构所处碱基位置分别为:80~120、120~240、240~360、360~480、400~520、640~760、760~880、800~920和1 420~1 540。本研究为低能离子注入介导的原核微生物进化提供了直接的分子证据。
