Fermentation optimization of maltose-binding protein fused to neutrophil-activating protein from Escherichia coli TB1

Background The fermentation conditions of recombinant maltose-binding protein fused to neutrophil-activating protein (rMBP-NAP) of Helicobacter pylori were optimized from Escherichia coli TB1 with varying medium, inoculum age and size, time, inducer, pH and temperature in batch fermentation. Results It was revealed that the optimal conditions for the production of rMBP-NAP in shake flask were as follows: M9 medium (with 3% yeast extract powder added), inoculum age of 19 h, inoculum size of 6%, initial pH of 6.6, temperature of 37°C, and 0.7 mmoL/L IPTG inducted 21 h in a 50 mL/250 mL shake flask. The recombinant protein yield was increased from 59 to 592 mg/L after optimization. Fermentation process conducted in a 10 L fermenter with similar conditions could get 30 g/L wet cell and 1.738 g/L soluble protein with the rMBP-NAP expression level of 11.9%. Conclusion The results improve the expression level of rMBP-NAP, and it is expected that these optimized conditions can be well applied for large scale production of rMBP-NAP.

The effect of underwater partial body-weight-supported treadmill training on hindlimb locomotor function recovery and on the expression of brain-derived neurotrophic factor and neurotrophin-3 in rats after spinal cord injury / 中华物理医学与康复杂志

Objective To observe the efficacy of underwater partial body-weight-supported treadmill training in repairing spinal cord injury (SCI) and its relationship with spinal nerve plasticity. Methods A total of 40 Sprague-Dawley rats were randomly divided into five groups: a sham model group, a model control group, an underwater training group, a partial body-weight-supported treadmill training (PBWSTT) group and an underwater PBWSTT group. A rat model of SCI was induced by contusion of the T10 segment with a Multicenter Animal Spinal Cord Injury Study (MASCIS) impactor. One week post-operation, different rehabilitation strategies, such as free exercise in water, BWSTT and underwater PBWSTT, were administered to the rats in the underwater training groups for 8 weeks.Those in the sham model group and model control group were given no training. The Basso, Beattie and Bresnahan (BBB) locomotor rating scale and a climbing test were used to evaluate the recovery of hindlimb locomotor function.The expression of brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (NT-3) in the spinal cords was detected with immunohistochemical methods. Results Nine weeks post-operation, hindlimb locomotor function had improved significantly more in the underwater PBWSTT group than in underwater training group or the BWSTT group.The expression of BDNF in the 3 training groups was significantly higher than in the model control group, though there was no significant difference among the 3 training groups. The expression of NT-3 in the underwater PBWSTT group increased more significantly than in the BWSTT group, however there was no significant difference between the underwater PBWSTT group and the underwater training group. Conclusion Underwater PBWSTT can promote the recovery of hindlimb locomotor function in rats after SCI, probably through increasing the expression of BDNF and NT-3 and thus promoting neural plasticity in the spinal cord.