Conclusions
This study presents a novel experimental design for assessment of stress
combined with an innovative approach for systems-level analyses of
molecular phenotypes (DIA-LCMS2). Specific organismal phenotypes (blood
osmolality, body condition, feeding rate) were found to indicate extreme
salinity stress in O. mossambicus . The rate-independent salinity
maximum and critical threshold salinity were determined using a
comprehensive set of acclimations and a generalized protocol that is
applicable to other species. The DIA-LCMS2 approach was shown to reveal
comprehensive molecular phenotypes in ecologically relevant samples. The
data generated in this study were used to produce protein networks which
elucidate major mechanisms of ionic and mitochondrial protein regulation
in response to hypersalinity in general and with respect to the critical
threshold. These networks help explain how fish modulate energy
metabolism, cell adhesion, and cell structure when experiencing salinity
stress below and above the critical limit.