Objective To investigate the effect of early closed reduction and percutaneous Kirschner wire pinning for Gartland type Ⅱ and Ⅲ pediatric supracondylar humerus fractures.Methods Clinical data of 123 children with Gartland type Ⅱ and Ⅲsupracondylar humerus fractures admitted to our hospital from January 2021 to December 2022 were retrospectively analyzed.According to the time from injury to operation,they were divided into early group(≤ 24 h)and delayed group(＞24 h).The perioperative conditions,postoperative complications,fracture healing,and elbow joint functional recovery were compared between the two groups.Results Compared to the delayed group,the early group had less operation time[(22.9±11.3)min vs.(40.3±17.5)min,t=-6.116,P=0.000],less number of intraoperative fluoroscopy[(10.6±4.5)times vs.(17.4±5.5)times,t=-7.471,P=0.000],shorter hospital stay[(3.3±1.0)d vs.(4.2±1.3)d,t=-3.866,P=0.000],and less hospitalization cost[(10 555.0±971.2)yuan vs.(10 972.4±938.9)yuan,t=-2.345,P=0.021].The rate of anatomical reduction in the early group was higher than that in the delayed group[79.0％(60/76)vs.59.6％(28/47),x2=5.354,P=0.021].No serious complications such as vascular and nerve injury,compartment syndrome,ischemic myosclerosis,myositis ossificans,or cubitus varus and valgus occurred in both group after surgery.The incidences of tension blisters[6.6％(5/76)vs.23.4％(11/47),x2=7.265,P=0.007],plaster loosening[22.4％(17/76)vs.40.4％(19/47),x2=4.574,P=0.032],and pin tract infection[2.6％(2/76)vs.14.9％(7/47),x2=4.757,P=0.029]in the early group were lower than those in the delayed group.The fracture union time,and the time to start active and full weight-bearing activities in the early group were earlier than those in the delayed group(P＜0.05).The Flynn elbow joint scores at 3 and 6 months after surgery in the early group were better than those in the delayed group(Z=-3.469,P=0.001;Z=-2.961,P=0.003).Conclusion Early closed reduction and percutaneous Kirschner wire pinning is effective in the treatment of pediatric supracondylar humerus fractures,which can shorten the operation time and hospital stay,reduce the hospitalization cost,lower the incidence of complications,and restore elbow joint function in early stage.

Objective To investigate the effect of early closed reduction and percutaneous Kirschner wire pinning for Gartland type Ⅱ and Ⅲ pediatric supracondylar humerus fractures.Methods Clinical data of 123 children with Gartland type Ⅱ and Ⅲsupracondylar humerus fractures admitted to our hospital from January 2021 to December 2022 were retrospectively analyzed.According to the time from injury to operation,they were divided into early group(≤ 24 h)and delayed group(＞24 h).The perioperative conditions,postoperative complications,fracture healing,and elbow joint functional recovery were compared between the two groups.Results Compared to the delayed group,the early group had less operation time[(22.9±11.3)min vs.(40.3±17.5)min,t=-6.116,P=0.000],less number of intraoperative fluoroscopy[(10.6±4.5)times vs.(17.4±5.5)times,t=-7.471,P=0.000],shorter hospital stay[(3.3±1.0)d vs.(4.2±1.3)d,t=-3.866,P=0.000],and less hospitalization cost[(10 555.0±971.2)yuan vs.(10 972.4±938.9)yuan,t=-2.345,P=0.021].The rate of anatomical reduction in the early group was higher than that in the delayed group[79.0％(60/76)vs.59.6％(28/47),x2=5.354,P=0.021].No serious complications such as vascular and nerve injury,compartment syndrome,ischemic myosclerosis,myositis ossificans,or cubitus varus and valgus occurred in both group after surgery.The incidences of tension blisters[6.6％(5/76)vs.23.4％(11/47),x2=7.265,P=0.007],plaster loosening[22.4％(17/76)vs.40.4％(19/47),x2=4.574,P=0.032],and pin tract infection[2.6％(2/76)vs.14.9％(7/47),x2=4.757,P=0.029]in the early group were lower than those in the delayed group.The fracture union time,and the time to start active and full weight-bearing activities in the early group were earlier than those in the delayed group(P＜0.05).The Flynn elbow joint scores at 3 and 6 months after surgery in the early group were better than those in the delayed group(Z=-3.469,P=0.001;Z=-2.961,P=0.003).Conclusion Early closed reduction and percutaneous Kirschner wire pinning is effective in the treatment of pediatric supracondylar humerus fractures,which can shorten the operation time and hospital stay,reduce the hospitalization cost,lower the incidence of complications,and restore elbow joint function in early stage.

As self-subunit swapping chaperones or metallochaperones, the activators assist nitrile hydratases to take up metal ions and they are essential for active expression of nitrile hydratases. Compared with nitrile hydratases, the activators have a low sequence identity. Study of the activation characteristics and the relationships between structures and functions of the activators is of great significance for understanding the maturation mechanism of nitrile hydratase. We co-expressed low-molecular-mass nitrile hydratase (L-NHase) from Rhodococcus rhodochrous J1 with four heterologous activators respectively and determined their activation abilities. Then we made sequence analysis and structure modelling, and studied the functions of the important domains of the activators. Results showed that all four heterologous activators could activate L-NHase, however, the specific activities of L-NHases were different after activation. L-NHase showed the highest specific activity after being activated by activator A, which was 97.79% of that of the original enzyme, but the specific activity of L-NHase after being activated by activator G was only 23.94% of that of the original enzyme. Activator E and activator G had conserved domains (TIGR03889), and deletion of their partial sequences resulted in a substantial loss of activation abilities for both activators. Replacing the N-terminal sequence of activator G with the N-terminal sequence of activator E, and adding the C-terminal sequence of activator E to the C-terminus of activator G could increase the specific activity of L-NHase by 178.40%. The activation by nitrile hydratase activators was universal and specific, and the conserved domains of activators were critical for activation, while the N-terminal domain and C-terminal domain also had important effects on activation.

Bacillus subtilis can be widely used as an important microorganism for metabolic engineering and recombinant proteins expression in industrial biotechnology and synthetic biology. However, it is difficult to make accurate regulation of exogenous gene by biological tools in B. subtilis, which limits the application of B. subtilis in synthetic biology. The purpose of this study is to develop regulatory tools for precise control of gene expression by using non-coding RNAs, by which the activation of heterologous gene could be achieved without the auxiliary protein factors. We constructed the synthetic riboswitch E and aptazyme AZ using the theophylline aptamer. Six different native promoters from B. subtilis were functionally adapted with the E and AZ to fabricate an array of novel regulatory elements activated by theophylline. Then, we determined the performance of these elements using green fluorescence protein as reporter, and then further verified using red fluorescence protein and pullulanase as cargo proteins. Results showed that the same kind of RNA elements with different promoters showed different levels of efficiency. Promoter PsigW and E combination (sigWE) had the highest induction rate in B. subtilis. Compared with the control group, it can produce the induction rate of 16.8. Promoter PrpoB and AZ combination (rpoBAZ) showed the highest induction rate of 6.2. SigWE mediated mCherry induction rate was 9.2, and P43E mediated pullulanase induction rate was 32.8, in which enzyme activity reached 81 U/mL. This study confirmed that GFP, mCherry and pullulan can all be regulated by riboswitch and aptazyme, but there were differences between different combinations of promoters with RNA regulators.
Bacillus subtilis ; Promoter Regions, Genetic ; RNA ; Recombinant Proteins ; Theophylline

Enzymatic synthesis is an important way to produce β-alanine, but the biological method is expensive generally because of the high price of substrate. In this paper, a two-step enzymatic cascade system was developed, combining L-aspartase from Escherichia coli DH5α and L-aspartate α-decarboxylase from Corynebacterium glutamicum. This system catalyzes Fumarate and ammonia to β-alanine. The optimal ratio of AspA and PanD was 1:80 (W/W), and the concentration of AspA was 10 μg/mL, at 37 ℃ and pH 7.0. When the concentration of Fumarate was 100 mmol/L, the reaction reached its equilibrium after 8 h, and the yield of β-alanine was 90 mmol/L (7 g/L). The yield of β-alanine can reach 126 mmol/L (9.8 g/L) when the concentration of Fumarate increased to 200 mmol/L. Extending reaction time, the conversion rate did not change obviously. Using this two-step enzymatic cascade system, β-alanine from cheaper substrate Fumarate can be obtained.

In proteins of thermophilic bacteria, Gly is tend to be replaced by Ala and Lys is tend to be replaced by Arg to adapt the high temperature. In order to improve the thermal stability of phenylalanine hydroxylase (PAH) from Chromobacterium violaceum, all the Gly on PAH were mutated to Ala and Lys to Arg. Positive mutant enzymes with improved thermal stability were selected, followed by combined mutation and characterization. The results revealed that half-lives of K94R and G221A mutants at 50 °C were 26.2 min and 16.8 min, which were increased by 1.9-times and 0.9-times than the parent enzyme (9.0 min). The residual activity of K94R/G221A mutant was improved to 65.6% after keeping at 50 °C for 1 h, which was 6.6 time higher than the parent enzyme (8.6%). Circular dichroism (CD) spectroscopy revealed that Tm values of the parent enzyme, K94R, G221A and K94R/G221A were 51.5 ℃, 53.8 ℃, 53.1 ℃ and 54.8 ℃, respectively. According to the protein structure simulation, the two mutations were located on flexible loop. In the K94R mutant, the mutated Arg94 on the surface of the enzyme formed an extra hydrogen bond with Ile95, which stabilized the located loop. In the G221A mutant, the mutated Ala221 formed hydrophobic interaction with Leu281, which could stabilize both the loop and flexible area of the C-terminus of G221A. The results not only provided a reference for protein modification on thermal stability, but also laid the foundation for application of phenylalanine hydroxylase in the field of functional foods.
Bacterial Proteins ; biosynthesis ; genetics ; Chromobacterium ; enzymology ; Enzyme Stability ; Hot Temperature ; Kinetics ; Mutagenesis, Site-Directed ; Mutation ; Phenylalanine Hydroxylase ; biosynthesis ; genetics ; Protein Engineering

Microbial nitrilases have attracted increasing attention in nitrile hydrolysis for carboxylic acid production in recent years. A bacterium with nitrilase activity was isolated and identified as Pseudomonas putida CGMCC3830 based on its morphology, physiological and biochemical characteristics, as well as 16S rRNA gene sequence. The nitrilase production was optimized by varying culture conditions using the one-factor-at-a-time method and response surface methodology. Glycerol 13.54 g/L, tryptone 11.59 g/L, yeast extract 5.21 g/L, KH2PO4 1 g/L, NaCl 1 g/L, urea 1 g/L, initial pH 6.0 and culture temperature 30 degrees C were proved to be the optimal culture conditions. It resulted in the maximal nitrilase production of 36.12 U/mL from 2.02 U/mL. Investigations on substrate specificity demonstrate P. putida nitrilase preferentially hydrolyze aromatic nitriles. When applied in nicotinic acid synthesis, 2 mg/mL P. putida cells completely hydrolyzed 20.8 g/L 3-cyanopyridine into nicotinic acid in 90 min. The results indicated P. putida CGMCC3830 displayed potential for industrial production of nicotinic acid.
Aminohydrolases ; biosynthesis ; Culture Media ; Hydrolysis ; Niacin ; biosynthesis ; Nitriles ; metabolism ; Pseudomonas putida ; enzymology ; Pyridines ; metabolism ; RNA, Ribosomal, 16S ; genetics ; Substrate Specificity ; Temperature