Carbon Source Induced Gene Expression

Investigation of whole genome gene expression level changes in Streptomyces sp. SirexAA-E (ActE) when grown on different carbon sources. The results of this study demonstrate that ActE upregulates a small number of genes specific for the utilization of the avaliable carbon source. Cellulolytic Streptomyces sp. SirexAA-E (ActE), isolated from the pinewood-boring wasp Sirex noctilio, has a genome enriched for biomass utilization. The secreted proteomes obtained from growth on pure polysaccharides catalyzed hydrolysis of cellulose, mannan, and xylan with specific activities comparable to Spezyme CP, a commercial cellulase preparation. During reaction of an ActE secretome with cellulose, reducing sugar release was markedly stimulated in the presence of O2. ActE also expresses and secretes an expanded repertoire of enzymes during growth on natural and pre-treated biomass. These results indicate a new microbial contribution to biomass utilization that is widely distributed in natural environments by insects Streptomyces sp. ActE was grown in minimal medium supplimented with 0.5% carbon source (glucose, sigmacell-20, xylan, chitin, cellobiose, or AFEX). Cells were grown for 7 days and total RNA was extracted from the cell pellet. At least 3 biological replicates were performed for each carbon source (glucose, 3; sigmacell, 3; xylan, 5; chitin, 3; cellobiose 3; AFEX 3). Each biological replicate contained 3 technical replicates. The complete dataset were RMA Background Corrected, quantile normalized, the RMA algorithm was utilized by DNAStar ArrayStar.本研究针对以不同碳源培养的链霉菌属SirexAA-E（Streptomyces sp. SirexAA-E，下称ActE）的全基因组基因表达水平变化展开调查。研究结果显示，ActE会上调少量与对应可利用碳源代谢特异性相关的基因。从蛀木胡蜂（Sirex noctilio）体内分离得到的解纤维素链霉菌属SirexAA-E（ActE），其基因组富含生物质代谢相关基因。以纯多糖为碳源培养得到的ActE分泌蛋白质组，可催化纤维素、甘露聚糖与木聚糖的水解，其比活与商业纤维素酶制剂Spezyme CP相当。在ActE分泌蛋白质组与纤维素的反应体系中，氧气（O₂）的存在可显著促进还原糖的释放。在天然生物质与预处理生物质上培养时，ActE还可表达并分泌更为丰富的酶系。上述结果表明，一类与昆虫共生、广泛分布于自然环境的新型微生物可参与生物质代谢，本研究中的ActE便属于此类微生物。本研究将ActE接种于添加0.5%碳源（葡萄糖、Sigmacell-20、木聚糖、几丁质、纤维二糖或氨纤维爆破预处理（AFEX））的基础培养基中培养。所有菌株均培养7天后，收集菌体沉淀并提取总RNA。每种碳源均设置至少3次生物学重复：葡萄糖3次、Sigmacell-20 3次、木聚糖5次、几丁质3次、纤维二糖3次、AFEX预处理生物质3次。每个生物学重复均包含3次技术重复。完整数据集经RMA背景校正与分位数归一化处理，分析过程采用DNAStar ArrayStar软件的RMA算法完成。