Comparative proteome analysis reveals proteins involved in salt adaptation in Photobacterium damselae subsp. piscicida

Abstract

Proteomic approaches were applied to investigate whether Photobacterium damselae subsp. piscicida (Phdp) can directly sense and respond to growth conditions under different salinities, 0.85% and 3.5% NaCl concentrations, mimicking the osmotic conditions in host and marine water bodies, respectively. Proteins significantly altered were analyzed by two-dimensional gel electrophoresis (2-DE), liquid chromatography-electrospray ionization-quadrupole-time-of-flight tandem mass spectrometry (LC-ESI-Q-TOF MS/MS) and bioinformatics analysis, thus resulting in 16 outer membrane proteins (OMPs), 12 inner membrane proteins (IMPs), and 20 cytoplasmic proteins (CPs). Quantitative real-time PCR was also applied to monitor the mRNA expression level of these target proteins. Cluster of orthologous groups of protein (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 mainly related to energy production and conversion, compatible solutes (carbohydrates, amino acids and their derivatives) biogenesis and transport. Differentially expressed proteins identified in the current study could be used to elucidate the salt adaptation mechanisms of Phdp during their transition between host cells and the marine habitats.

Low salinity activates a virulence program in the generalist marine pathogen Photobacterium damselae subsp. damselae

“…The enhanced expression of these gene categories was also observed in P. damselae subsp. piscicida when shifting from low to high salt ( 61 ) and in E. coli in response to growth in seawater ( 55 ).…”

Salinity fluctuation influencing biological adaptation: growth dynamics and Na+/K+-ATPase activity in a euryhaline bacterium

“…DYB exposed to hyperhaline versus hypohaline fluctuation, probably due to differences in the regulation mechanism. It has previously been shown that microorganisms have developed a range of strategies for acclimation to both low and high salt concentrations . It was also reported that the copepod Eurytemora affinis exhibits lower survival and longer development times when reared at low salinity compared to individuals reared at higher salinities .…”