Proteomic analysis reveals stress-responsive proteins of Photobacterium damselae under different salt concentrations and during invasion of fish kidney cells

• Main Authors: Min-Yuan Chuang, 莊閔元
• Other Authors: Wei-Jung Chen
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/60106678775713123468

碩士 === 國立宜蘭大學 === 生物技術研究所碩士班 === 97 === Being an island surrounded by sea, Taiwan’s fisheries are well developed and net-cage fish farming becomes a promising economic sector. However, an outbreak of fish photobacteriosis is recognized as one of the most threatening bacterial diseases in aquaculture worldwide due to its wide host range and massive mortality. Photobacterium damselae subsp. piscicida is the causative agent of this serious fish disease. The astonishing flexibility and adaptability of the bacterial cell has enabled many marine pathogenic species to freely transition between dramatically different environmental conditions, especially osmotic pressure. In the current study, 0.85% and 3.5% NaCl concentrations were used to mimic the osmotic conditions in host and marine water bodies, respectively. Proteomic approaches were applied to investigate the expression pattern of the sub-proteomes of P. damselae subsp. piscicida in different salinities. Proteins significantly altered were analyzed by 2-DE and LC-ESI-Q-TOF MS/MS, thus resulted in 16 outer membrane proteins (OMPs), 12 inner membrane proteins (IMPs), and 20 cytoplasmic proteins (CPs), respectively. COG analysis revealed that when shifting from 3.5% to 0.85% salinity, the majority of the up-regulated proteins were involved in posttranslational modification, protein turnover, and chaperones, while the down-regulated proteins were related to energy production and conversion. Quantitative real-time PCR was performed to confirm the proteomic results. Furthermore, The protein profile changes that underlie this ability can determine the success of the pathogen in the host. An investigation of the differential protein expression of this pathogen during invasion was undertaken utilizing fish kidney cell line. However, it is apparent that 39 identified proteins are not directly involved in damaging or injuring host cells. Rather, these proteins seem to be primarily involved in the metabolism and utilization of nutrients in the host environments. These results will be helpful for expanding our knowledge on the mechanism of survival between a host and seawater for P. damselae subsp. piscicida and open very promising prospects towards the development of an effective anti-photobacteriosis vaccine.