Freshwater microalga Haematococcus lacustris rich in astaxanthin, as a supplemental live diet can directly supply natural astaxanthin to the aquaculture organisms, except marine aquaculture organisms, since H. lacustris cannot tolerate seawater salinity. The objective of the present study is to provide a salinity acclimation method that allows H. lacustris to survive and accumulate astaxanthin with the aim of developing a novel supplemental live diet for marine aquaculture organisms. H. lacustris cultured in freshwater was subjected to different stepwise salinity acclimation processes (two-, three-, and four-shift). As the controls, H. lacustris was exposed to five constant salinities conditions (0, 0.05, 0.075, 0.3, and 0.6 M NaCl, respectively). Among the controls, almost all cells in the 0.3 M and 0.6 M NaCl conditions died immediately. In contrast, H. lacustris in the stepwise salinity acclimation processes survived in 0.6 M NaCl (equivalent to seawater salinity of 35 psu), showing the highest living-cell proportion (50.0%) and astaxanthin yield (0.72 mg·L-1) in the four-shift. The present study first demonstrated that H. lacustris tolerated seawater salinity through a stepwise acclimation process, proving a new strategy to supply live microalgal diets rich in natural astaxanthin for marine aquaculture.
Cu/Zn superoxide dismutase (Cu/Zn-SOD) is a key antioxidant enzyme that catalyzes superoxide radical dismutation. Here, an integrated computational-assisted, structure-guided engineering strategy was applied to improve Cu/Zn-SOD catalytic performance. Gln22 and Glu134 were identified as promising engineering sites, and saturation mutagenesis yielded Q22I and E134 M as the most beneficial single substitutions, with specific activities 1.55- and 2.39-fold higher than wild type (WT), respectively. Combining both substitutions generated M2 (Q22I/E134M), which showed the highest specific activity of 7121.0 U mg-1, corresponding to a 3.43-fold increase over WT. The optimal temperature of Q22I and M2 increased from 40 to 50 °C, and M2 also exhibited enhanced thermostability. Kinetic analysis showed that M2 had a 41.18% lower Km and a 2.95-fold higher Vmax than WT. Molecular docking suggested complementary effects of Q22I and E134 M on structural stability and active-site optimization, supporting improved catalytic performance. These findings provide a basis for engineering efficient, thermostable SODs.
Cardiogenic shock (CS) remains a major clinical challenge, with persistently high short-term mortality despite advances in reperfusion therapy, pharmacological support, and mechanical circulatory support. This review reassesses the conceptual evolution of CS and examines why hemodynamic-centric diagnostic and therapeutic strategies have failed to yield meaningful improvements in outcomes. Historically, CS has been defined by cardiac-oriented macrocirculatory compromise, and contemporary definitions and staging systems have improved risk stratification but remain largely hemodynamics-focused and primarily validated in intensive care settings. Increasing evidence indicates that inflammatory activation, microcirculatory dysfunction, endothelial injury, and metabolic derangements are central determinants of shock progression and organ failure. Integrating multimodal diagnostic approaches-including bedside assessment of microcirculation and inflammation, omics-based phenotyping, advanced echocardiographic techniques, and artificial intelligence-assisted risk stratification-may enable earlier recognition, more precise classification, and improved risk stratification across the continuum of care. Reframing cardiogenic shock as a dynamic, multisystem disorder supports a shift from hemodynamic-centric paradigms toward multimodal precision care, with important implications for clinical management and future trial design.