Construction of highly active and stable recombinant nattokinase by engineered bacteria and computational design.

Nattokinase (NK) is an enzyme that has been recognized as a new potential thrombolytic drug due to its strong thrombolytic activity. However, it is difficult to maintain the enzyme activity of NK during high temperature environment of industrial production. In this study, we constructed six NK mutants with potential for higher thermostability using a rational protein engineering strategy integrating free energy-based methods and molecular dynamics (MD) simulation. Then, wild-type NK and NK mutants were expressed in Escherichia coli (E. coli), and their thermostability and thrombolytic activity were tested. The results showed that, compared with wild-type NK, the mutants Y256P, Q206L and E156F all had improved thermostability. The optimal mutant Y256P showed a higher melting temperature (Tm) of 77.4 °C, an increase of 4 °C in maximum heat-resistant temperature and an increase of 51.8 % in activity at 37 °C compared with wild-type NK. Moreover, we also explored the mechanism of the increased thermostability of these mutants by analysing the MD trajectories under different simulation temperatures.

Anthraquinone/activated carbon electrochemical sensor and its application in acetaminophen analysis.

Acetaminophen (AC) can inhibit the synthesis of prostaglandins in the body, and has antipyretic and analgesic effects. In this paper, a two-step microwave impregnation method was used to prepare anthraquinone (AQ)-doped carbon composite, which were applied to the surface modification of glassy carbon electrodes (GCE) for the determination of acetaminophen (AC) using differential pulse voltammetry (DPV). The composites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman and Fourier infrared spectroscopy (FT-IR). The results showed that anthraquinone was successfully modified on the surface of activated carbon. The peak current of AC increased with its concentration in the range of 0.1 µM to 700 µM (R2 = 0.998) and a detection limit of 0.05 µM was obtained with 20%AQ doped carbon electrochemical sensor (20%AQ-C/GCE). Electrochemical Impedance Spectroscopy (EIS) test results indicated that the charge transfer resistance (Rct) of 20%AQ-C/GCE is only the one-fourth of that of bare GCE. The proposed 20%AQ-C/GCE sensor has good stability, reproducibility and selectivity for the detection of AC. The sensor is also suitable for the detection of real samples, indicating its good practicality.

Effects of rehabilitation nursing care on deep vein thrombosis of the lower limbs following spinal fractures.

OBJECTIVE: To explore the preventive effect of rehabilitation nursing care for deep vein thrombosis (DVT) of the lower limbs following spinal fractures, and to analyze its influence on the hemorheology of patients. METHODS: A total of 99 patients with spinal fractures were allocated into a study group (n=50) and control group (n=49), and they were treated with internal fixation plus vertebroplasty. Afterwards, patients in the control group were given routine care and postoperative rehabilitation, and those in the study group received rehabilitation nursing care on the day after surgery, including posture guidance, massage of both lower limbs, and functional training. The functional training was consecutively performed until free movement of the legs was possible. All patients were reexamined after three months. The incidence of low-limb DVT, pain, and swelling, as well as the degree of swelling, hemorheology, quality of life, and patient satisfaction were compared between the two groups. RESULTS: The study group had less frequent low-limb DVT, pain and swelling than the control group (all P<0.05). In the study group, the degree of swelling was significantly reduced, with earlier return to normal activity and shorter hospital stay (all P<0.05). After intervention, plasma viscosity, whole blood low/high shear viscosity and erythrocyte aggregation (EA) decreased in both groups, especially in the study group (all P<0.05). Although GQOL-74 scores increased in both groups, there was a more significant increase that occurred in study group (all P<0.001). Patients in the study group were more satisfied with nursing services than those in the control group (P<0.05). CONCLUSION: Rehabilitation nursing care contributes to the improvement of hypercoagulable states and the prevention of lower-limb DVT for surgically treated patients with spinal fractures, and it is effective in relieving pain and swelling of the lower limbs, thereby enhancing quality of life and patient satisfaction.

Fabrication of an N-doped mesoporous bio-carbon electrocatalyst efficient in Zn-air batteries by an in situ gas-foaming strategy.

A nitrogen doped bio-carbon catalyst with high specific surface area and a hierarchical interconnected porous structure was fabricated by an in situ gas-foaming strategy from sodium alginate and ammonium chloride. The optimized catalyst displays a fabulous ORR activity, providing a facile approach for the mass production of metal-free bio-carbon catalysts in fuel cells and metal-air batteries.

The immunoglobulin-like cell adhesion molecule hepaCAM modulates cell adhesion and motility through direct interaction with the actin cytoskeleton.

Previously, we reported the identification of a novel immunoglobulin-like cell adhesion molecule hepaCAM that promotes cell-extracellular matrix (ECM) interactions including cell adhesion and motility. Cell-ECM interactions are known to be directed by the actin cytoskeleton. In this study, we examined the association of hepaCAM with the actin cytoskeleton. We found that hepaCAM was partially insoluble in Triton X-100 and colocalized with the actin cytoskeleton on the plasma membrane. Disruption of F-actin decreased the detergent insolubility and disturbed the subcellular localization of hepaCAM. Coimmunoprecipitation and F-actin cosedimentation assays revealed that hepaCAM directly bound to F-actin. In addition, we constructed three N- and C-terminal domain-deleted mutants of hepaCAM to determine the actin-binding region as well as to evaluate the effect of the domains on the biological function of hepaCAM. Detergent solubility assays showed that the cytoplasmic domain of hepaCAM might be required for actin association. However, deletion of either the extracellular or the cytoplasmic domain of hepaCAM abolished actin coprecipitation as well as delayed cell-ECM adhesion and cell motility. The data suggest that an intact hepaCAM protein is critical for establishing a stable physical association with the actin cytoskeleton; and such association is important for modulating hepaCAM-mediated cell adhesion and motility.