【目的】分析油麦吊云杉cpDNA的特征和密码子偏好性,为云杉属植物叶绿体基因组学提供研究依据。【方法】通过Ilumina HiSeq测序平台对油麦吊云杉cpDNA进行测序,并利用Codon W 1.4.2和CUSP软件对其密码子偏性进行分析。【结果】油麦吊云...【目的】分析油麦吊云杉cpDNA的特征和密码子偏好性,为云杉属植物叶绿体基因组学提供研究依据。【方法】通过Ilumina HiSeq测序平台对油麦吊云杉cpDNA进行测序,并利用Codon W 1.4.2和CUSP软件对其密码子偏性进行分析。【结果】油麦吊云杉cpDNA是一个全长为124161 bp的环状DNA分子,与典型的具有保守的四分体cpDNA结构不同,油麦吊云杉cpDNA中存在反向重复区域的丢失,其cpDNA的GC含量为38.7%。油麦吊云杉cpDNA包含113个基因,其中蛋白质编码基因76个,核糖体RNA基因4个,转运RNA基因33个,系统发育分析显示,油麦吊云杉和西加云杉聚为一个独特的分支,油麦吊云杉cpDNA密码子不同位置上的GC含量从低到高依次是GC_(3)(49.39%)45的占86%,表明其密码子的偏性较弱;GC_(12)和GC_(3)的相关性不显著(r=0.1664,b=-0.1577);ENC频数比值分布在-0.05~0.05的基因频率占比57%,说明油麦吊云杉叶绿体基因组CUB受选择影响的同时也受到其他因素影响;油麦吊云杉cpDNA中大部分基因分布在PR2平面图的右下方,即T>A、G>C,说明在油麦吊云杉绿体基因组密码子的偏好性受选择、突变等因素的影响。最终UCU、AAA、GGU、GCA、GUU、UGU、UCC、CAU、GCU、CGU、GAA和AUU等12个密码子被确定为油麦吊云杉绿体基因组的最优密码子。【结论】油麦吊云杉cpDNA密码子偏好使用A或U结尾的密码子,选择和突变是其CUB的主要影响因素。展开更多
The film cooling performance of chevron holes with different inclination angles and exit lateral diffusion angles has been studied experimentally and numerically. The inclination angles include 35° and 55°. ...The film cooling performance of chevron holes with different inclination angles and exit lateral diffusion angles has been studied experimentally and numerically. The inclination angles include 35° and 55°. The exit lateral diffusion angles include 20° and 25°. The film cooling effectiveness, heat transfer coefficient and discharge coefficient were measured on a flat plate model by transient liquid crystal measurement technique under four blowing ratios. The results show that the large inclination angle reduces the film cooling effectiveness. The influence of diffusion angle has two aspects: the large diffusion angle leads to mainstream ingestion and decreases film cooling effectiveness at M=1.0 and 1.5; however, the large diffusion angle increases the film cooling effectiveness at high blowing ratio of 2.0, because the larger hole exit area decreases the normal momentum component of the film jet. The large inclination angle decreases the heat transfer coefficient in the right downstream region at M=0.5 and 1.0. The large diffusion angle enhances the heat transfer in the right downstream of the holes in M=0.5～1.5 conditions. The chevron hole with large inclination angle generally has the highest discharge coefficient.展开更多
文摘【目的】分析油麦吊云杉cpDNA的特征和密码子偏好性,为云杉属植物叶绿体基因组学提供研究依据。【方法】通过Ilumina HiSeq测序平台对油麦吊云杉cpDNA进行测序,并利用Codon W 1.4.2和CUSP软件对其密码子偏性进行分析。【结果】油麦吊云杉cpDNA是一个全长为124161 bp的环状DNA分子,与典型的具有保守的四分体cpDNA结构不同,油麦吊云杉cpDNA中存在反向重复区域的丢失,其cpDNA的GC含量为38.7%。油麦吊云杉cpDNA包含113个基因,其中蛋白质编码基因76个,核糖体RNA基因4个,转运RNA基因33个,系统发育分析显示,油麦吊云杉和西加云杉聚为一个独特的分支,油麦吊云杉cpDNA密码子不同位置上的GC含量从低到高依次是GC_(3)(49.39%)45的占86%,表明其密码子的偏性较弱;GC_(12)和GC_(3)的相关性不显著(r=0.1664,b=-0.1577);ENC频数比值分布在-0.05~0.05的基因频率占比57%,说明油麦吊云杉叶绿体基因组CUB受选择影响的同时也受到其他因素影响;油麦吊云杉cpDNA中大部分基因分布在PR2平面图的右下方,即T>A、G>C,说明在油麦吊云杉绿体基因组密码子的偏好性受选择、突变等因素的影响。最终UCU、AAA、GGU、GCA、GUU、UGU、UCC、CAU、GCU、CGU、GAA和AUU等12个密码子被确定为油麦吊云杉绿体基因组的最优密码子。【结论】油麦吊云杉cpDNA密码子偏好使用A或U结尾的密码子,选择和突变是其CUB的主要影响因素。
基金Financial support from the National Basic Research Program of China "973" (Grant No. 2013CB035702)
文摘The film cooling performance of chevron holes with different inclination angles and exit lateral diffusion angles has been studied experimentally and numerically. The inclination angles include 35° and 55°. The exit lateral diffusion angles include 20° and 25°. The film cooling effectiveness, heat transfer coefficient and discharge coefficient were measured on a flat plate model by transient liquid crystal measurement technique under four blowing ratios. The results show that the large inclination angle reduces the film cooling effectiveness. The influence of diffusion angle has two aspects: the large diffusion angle leads to mainstream ingestion and decreases film cooling effectiveness at M=1.0 and 1.5; however, the large diffusion angle increases the film cooling effectiveness at high blowing ratio of 2.0, because the larger hole exit area decreases the normal momentum component of the film jet. The large inclination angle decreases the heat transfer coefficient in the right downstream region at M=0.5 and 1.0. The large diffusion angle enhances the heat transfer in the right downstream of the holes in M=0.5～1.5 conditions. The chevron hole with large inclination angle generally has the highest discharge coefficient.
