Studies on High Salinity Affecting Biofilm Formation and Expression of pel Operon Genes in Pseudomonas aeruginosa

• Main Authors: Chuan-Ru Wang, 王傳儒
• Other Authors: Huang Shiao-ping
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/10697960143327529980

碩士 === 輔英科技大學 === 醫學檢驗生物技術系碩士班 === 102 === Pseudomonas aeruginosa are Gram-negative opportunistic pathogens and can be found in the environments including soil, freshwater, and seawater. Multiple antibiotic resistance and biofilm formation are major problems in the treatment of Pseudomonas aeruginosa infection. Pseudomonas aeruginosa produces extracellular polysaccharides for biofilm development including alginate, Pel, and Psl. Pel play an important role in pellicle formation at the air-liquid interface and providing a structural scaffold for biofilm formation at early stages. The genes associated with Pel formation are pel operon including pelA-G. Since the high salt environment would inhibit the biofilm formation of Pseudomonas aeruginosa and the effect on extracellular polysaccharide in biofilm matrix is unclear, this study investigated the effects of salinity on bacterial growth, biofilm formation, pellicle formation, and mRNA expression of relevant genes in Pseudomonas aeruginosa. The obtained results were analyzed. First, the Pseudomonas aeruginosa grew well in medium either with or without supplemented NaCl. However, the growth curve showed a log-phase-delay in medium with supplemented NaCl. Second, the results of the biofilm formation indicated that the decreases of biofilm were proportional to the concentrations of supplemented NaCl including 17% in 300 mM NaCl, 40% in 500 mM NaCl, and 54% in 700 mM NaCl, respectively. Third, the results of the pellicle formation showed that the thickness in pellicle were decreased by the supplemented with NaCl including 18% in 300mM NaCl, 50% in 500mM NaCl, and 56% in 700mM NaCl, respectively. Fourth, the mRNA expression of pel operon was measured and the results showed that the low mRNA expression of pel operon in medium with supplemented NaCl. In conclusion, this study revealed that the supplemented NaCl in medium may cause the physiological changes in Pseudomonas aeruginosa including gene expression of pel operon, and biofilm formation.