2026-11-092026-11-09https://scholars.csmu.edu.tw/handle/123456789/38793Klebsiella pneumoniae adapts itself to various environments and is capable of causing a wild range of infections. How K. pneumoniae can switch physiological programs to ensure its survival in a specific ecological niche is still a mystery. Recently, it has become clear that small non-coding RNAs are crucial regulators that modulate diverse cellular processes to enable prokaryotic cells to adjust physiological fitness to environmental changes. Most small regulatory RNAs (srRNAs) exert their function in the post-transcriptional level via the binding of Hfq. The RNA chaperone Hfq contributes to the fitness and virulence of several pathogens. A number of Hfq-dependent srRNAs are proved to be important components of many regulatory circuits. Interestingly, in our previous study, several mutant phenotypes due to the deletion of K. pneumoniae hfq were drastically different from that demonstrated in other pathogens analyzed. In this project, we propose to elucidate the roles of Hfq-srRNAs in the modulation of K. pneumoniae cellular processes. To verify the pleiotropic effects of Hfq, gene-specific knockout mutant will be generated in a K1-serotype K. pneumoniae and the physiological characteristics and virulence potential of the hfq deletion mutants will be characterized. The Hfq-dependent srRNAs players which have their positive or negative regulatory roles in the control of existing regulatory circuits, such as CPS biosynthesis or envelop stress response, will be identified by means of the functional screen with a genetic approach. The subset of K. pneumoniae specific srRNAs that have no significant sequence homology with their counterparts in E. coli will be identified by means of the genomic SELEX (Systematic Evolution of Ligands by Exponential Enrichment) approach. A picture of how small regulatory RNAs modulate K. pneumoniae cellular functions, probably via a species-specific manner, is expected by the completion of this project.克雷白氏肺炎桿菌(Klebsiella pneumoniae) 可適應多變的環境並且具有造成多樣 化臨床感染的能力。究竟K. pneumoniae 如何轉換生理機制以允許其在特殊環境中生存 仍然是個謎團。近來許多研究證實Small non-coding RNAs 可調節多種細胞過程使得原 核細胞可以適應多種環境的變化。大部分的small regulatory RNAs (srRNAs) 藉由Hfq 的結合在後轉錄的層次上執行他們基因調控的功能。RNA-chaperone Hfq 被發現在數 個致病菌的生理適應與毒性表現具有重要的貢獻。許多Hfq-dependent srRNAs 被證實 是多種基因表現調節迴路中的重要分子。在我們先前的研究發現K. pneumoniae 的hfq 基因缺失造成多種不同於其他致病菌的生理特性，因此在本計畫中，我們將針對 Hfq-dependent srRNAs 調結K. pneumoniae 細胞反應的分子機制進行探討。為了進一步 釐清Hfq 對K. pneumoniae 的影響，基因缺失的突變菌株將被建構在K1 血清型的菌株 內，我們將針對該突變菌株的生理特性與毒性表現進行比較分析。此外針對可能調節 已知基因表現調控路徑的Hfq-dependent srRNAs ，我們將運用遺傳功能的策略進行搜 尋。至於在序列上缺乏與大腸桿菌的srRNAs 相似度的K. pneumoniae specific srRNAs，我們將運用genomic SELEX 的方法進行搜尋。藉由本計畫的完成，我們預 期將會對srRNAs 如何調節K. pneumoniae 的生理適應與毒性表現有更清楚的了解。Project