Fu Xiaohong, Zhang Xuemei, Jing Chunmei, Liu Lan, Yin Yibing, Jiang Junru
Chongqing International Science and Technology Cooperation, Chongqing, China.
Nan Fang Yi Ke Da Xue Xue Bao. 2013 Jan;33(1):18-21.
To investigate the effect of Pseudomonas quinolone signal (PQS) on the virulence of Pseudomonas aeruginosa.
Pseudomonas aeruginosa strain PAO1 was treated with PQS alone, PQS plus farnesol, or farnesol alone. The transcriptional levels of the regulator gene ExsA and virulence protein gene ExoS of type III secretion system were examined using quantitative real-time PCR, and spectrophotometry was employed to detect pyocyanin production in the bacteria. The adhesion and invasiveness of the treated PAO1 in cultured alveolar epithelial cells A549 were assessed on plate count agar, and their effects on the survival of a mouse model of peritonitis was compared.
The increase or decrease of PQS did not affect the growth of PAO1. Compared with the untreated bacteria, PQS-treated PAO1 showed obviously increased transcription levels of ExsA and ExoS (P<0.01) and pyocyanin production, which was significantly lowered by farnesol (P<0.01). In A549 cell cultures, farnesol-treated PAO1 exhibited significantly lowered adhesion and invasiveness, while PQS-treated PAO1 caused a significantly decreased survival time of mice with peritonitis (P<0.01). Farnesol treatment did not obviously affected ExsA transcription (P>0.05) but caused a significant reduction in the transcriptional level of Exos (P<0.05) in PAO1. PQS showed no significant effect on the adhesion and invasiveness of PAO1 (P<0.05).
PQS can maintain the adhesion and invasiveness of Pseudomonas aeruginosa, and in the hosts of the bacteria, PQS concentration is positively correlated with pyocyanin production and hence negatively with the survival time of the hosts.
研究喹诺酮信号（PQS）对铜绿假单胞菌毒力的影响。
用PQS单独处理、PQS加法尼醇或法尼醇单独处理铜绿假单胞菌PAO1菌株。采用定量实时PCR检测III型分泌系统调节基因ExsA和毒力蛋白基因ExoS的转录水平，并用分光光度法检测细菌中绿脓菌素的产生。在平板计数琼脂上评估处理后的PAO1在培养的肺泡上皮细胞A549中的黏附性和侵袭性，并比较它们对腹膜炎小鼠模型存活情况的影响。
PQS的增加或减少不影响PAO1的生长。与未处理的细菌相比，PQS处理的PAO1的ExsA和ExoS转录水平明显升高（P<0.01），绿脓菌素产生增加，而法尼醇可显著降低其水平（P<0.01）。在A549细胞培养物中，法尼醇处理的PAO1的黏附性和侵袭性显著降低，而PQS处理的PAO1导致腹膜炎小鼠的存活时间显著缩短（P<0.01）。法尼醇处理对PAO1中ExsA转录无明显影响（P>0.05），但导致Exos转录水平显著降低（P<0.05）。PQS对PAO1的黏附性和侵袭性无显著影响（P<0.05）。
PQS可维持铜绿假单胞菌的黏附性和侵袭性，在该细菌的宿主中，PQS浓度与绿脓菌素产生呈正相关，因此与宿主存活时间呈负相关。
