Transcriptomic response of the polycyclic aromatic hydrocarbon-degrading Sphingomonas sp. LH128 upon short-term starvation stress

This study examines genome-wide expression of the phenanthrene-degrading Sphingomonas sp. LH128 as a response to short-term starvation stress. For this purpose, the strain was subjected to complete nutrient starvation for 4h after growth on a rich medium. Survival was monitored by plating and transcriptomic response was determined by whole-genome microarray analysis. The data showed no major differences were obsrved in gene expression and the viability of the cells were not affected during short-term incubation time Transcriptomic response of phenanthrene degrading Sphingomonas sp. LH128 starved for 4h in isotonic solution of 0.01 mM MgS04 was studied using genome-wide gene expression analysis. For this purpose, the strain was pregrown in minimal medium to an OD600 of 0.5, washed twice with 0.01 mM MgS04 and resuspended in the same solution to an OD of 0.5. RNA was extracted both from starved cells and from the initial culture (non-starved cells) and cDNA was synthesized and labeled with Cy3. Transcriptomic response of three replicates were analyzed and compared with the initial inoculum

本研究以降解菲（phenanthrene）的鞘氨醇单胞菌属（Sphingomonas）菌株LH128为研究对象，探究其响应短期饥饿胁迫的全基因组表达特征。实验中，菌株先于丰富培养基中培养，随后置于完全营养饥饿环境中孵育4小时。通过平板涂布计数法监测细胞存活率，采用全基因组微阵列分析（whole-genome microarray analysis）测定转录组响应。数据显示，短期孵育期间，细胞的基因表达与细胞活力均未出现显著差异。

本研究同时针对在0.01 mM硫酸镁（MgSO4）等渗溶液中饥饿4小时的降解菲鞘氨醇单胞菌属菌株LH128，通过全基因组基因表达分析解析其转录组响应。具体实验流程如下：将菌株在基本培养基（minimal medium）中预培养至600纳米光密度值（OD600）为0.5，随后用0.01 mM硫酸镁溶液洗涤两次，并重悬于相同溶液中，使OD600达到0.5。分别从饥饿处理后的细胞与初始培养物（未饥饿处理的细胞）中提取核糖核酸（RNA），并合成互补脱氧核糖核酸（cDNA），以氰基3（Cy3）荧光基团进行标记。对三次生物学重复（replicates）的转录组响应进行分析，并与初始接种菌液进行比对。