State Key Laboratory of Veterinary Biotechnology, Division of Bacterial Diseases, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, People's Republic of China.
PLoS One. 2013;8(1):e53600. doi: 10.1371/journal.pone.0053600. Epub 2013 Jan 11.
In the respiratory tract and lung tissue, a balanced physiological response is essential for Actinobacillus pleuropneumoniae to survive various types of challenges. ClpP, the catalytic core of the Clp proteolytic complex, is involved in various stresses response and regulation of biofilm formation in many pathogenic bacteria. To investigate the role of ClpP in the virulence of A. pleuropneumoniae, the clpP gene was deleted by homologous recombination, resulting in the mutant strain S8ΔclpP. The reduced growth of S8ΔclpP mutant at high temperatures and under several other stress conditions suggests that the ClpP protein is required for the stress tolerance of A. pleuropneumoniae. Interestingly, we observed that the S8ΔclpP mutant exhibited an increased ability to take up iron in vitro compared to the wild-type strain. We also found that the cells without ClpP displayed rough and irregular surfaces and increased cell volume relative to the wild-type strain using scanning electron microscopy (SEM). Confocal laser scanning microscopy (CLSM) revealed that the S8ΔclpP mutant showed decreased biofilm formation compared to the wild-type strain. We examined the transcriptional profiles of the wild type S8 and the S8ΔclpP mutant strains of A. pleuropneumoniae using RNA sequencing. Our analysis revealed that the expression of 16 genes was changed by the deletion of the clpP gene. The data presented in this study illustrate the important role of ClpP protease in the stress response, iron acquisition, cell morphology and biofilm formation related to A. pleuropneumoniae and further suggest a putative role of ClpP protease in virulence regulation.
在呼吸道和肺部组织中，平衡的生理反应对于肺炎链球菌生存各种类型的挑战至关重要。ClpP 是 Clp 蛋白酶复合物的催化核心，参与许多病原菌的各种应激反应和生物膜形成的调节。为了研究 ClpP 在肺炎链球菌毒力中的作用，通过同源重组缺失了 clpP 基因，导致突变株 S8ΔclpP。S8ΔclpP 突变株在高温和其他几种应激条件下的生长减少表明，ClpP 蛋白是肺炎链球菌应激耐受所必需的。有趣的是，我们观察到 S8ΔclpP 突变株在体外摄取铁的能力比野生型菌株增加。我们还发现，与野生型菌株相比，没有 ClpP 的细胞使用扫描电子显微镜 (SEM) 显示出粗糙和不规则的表面以及增加的细胞体积。共聚焦激光扫描显微镜 (CLSM) 显示，与野生型菌株相比，S8ΔclpP 突变株的生物膜形成减少。我们使用 RNA 测序检查了肺炎链球菌野生型 S8 和 S8ΔclpP 突变株的转录谱。我们的分析表明，clpP 基因缺失导致 16 个基因的表达发生变化。本研究的数据表明 ClpP 蛋白酶在应激反应、铁摄取、细胞形态和生物膜形成方面对肺炎链球菌的重要作用，并进一步表明 ClpP 蛋白酶在毒力调节中的潜在作用。
