Engineering of Halide Methyltransferase BxHMT through Dynamic Cross-Correlation Network Analysis.

Halide methyltransferases (HMTs) provide an effective way to regenerate S-adenosyl methionine (SAM) from S-adenosyl homocysteine and reactive electrophiles, such as methyl iodide (MeI) and methyl toluene sulfonate (MeOTs). As compared with MeI, the cost-effective unnatural substrate MeOTs can be accessed directly from cheap and abundant alcohols, but shows only limited reactivity in SAM production. In this study, we developed a dynamic cross-correlation network analysis (DCCNA) strategy for quickly identifying hot spots influencing the catalytic efficiency of the enzyme, and applied it to the evolution of HMT from Paraburkholderia xenovorans. Finally, the optimal mutant, M4 (V55T/C125S/L127T/L129P), exhibited remarkable improvement, with a specific activity of 4.08 U/mg towards MeOTs, representing an 82-fold increase as compared to the wild-type (WT) enzyme. Notably, M4 also demonstrated a positive impact on the catalytic ability with other methyl donors. The structural mechanism behind the enhanced enzyme activity was uncovered by molecular dynamics simulations. Our work not only contributes a promising biocatalyst for the regeneration of SAM, but also offers a strategy for efficient enzyme engineering.

[Functional peptidomics analysis of Saccharomyces pastorianus protein hydrolysates based on different enzyme treatments].

The aim of this study is to explore differences in the peptidomics of Saccharomyces pastorianus protein hydrolysates treated with different enzymes. Briefly, differences in the peptide fingerprints and active peptides of neutral protease/papain-hydrolyzed S. pastorianus were analyzed using ultra-high performance liquid chromatography-high resolution mass spectrometry (UHPLC-HRMS) combined with PEAKS Online 1.7 analysis software, Peptide Ranker, and the BIOPEP database. Compared to traditional databases, the PEAKS Online uses de novo sequencing for analysis to obtain oligopeptides smaller than pentapeptides. It provides more comprehensive data of the peptide sample. In this study, enzymatic hydrolysates of S. pastorianus protein were prepared under the optimum conditions of neutral protease and papain respectively. In total, 7221 and 7062 polypeptides were identified in the hydrolysates of neutral protease and papain, respectively; among these polypeptides, 980 were common to the two enzymes. The 6241 and 6082 unique peptides found in the hydrolysates of neutral protease and papain, respectively, indicated that the peptide fingerprints of the two hydrolysates are quite different. Peptide Ranker predicted that 3013 (41.73%) and 3095 (43.83%) peptides were potentially bioactive in the hydrolysates of neutral protease and papain, respectively. According to the BIOPEP database, neutral protease and papain contained 295 and 357 active peptides, respectively; these peptides were mainly composed of angiotensin converting enzyme (ACE) inhibitors and dipeptidyl peptidase IV inhibitors and antioxidant peptides. The number of active peptides in the hydrolysate of papain was higher than that in the hydrolysate of neutral protease, but the total ion intensity of active peptides in the former was lower than that in the latter. This study revealed the influence of protease type on the composition of enzymatic hydrolysates from S. pastorianus protein. The above results provide a reference for the development of functional products of S. pastorianus protein peptides and the high-value utilization of yeast resources.

[Treatment of lateral ankle joint ligament sprain by shaking and poking manipulation based on finite element method].

OBJECTIVE: To conduct a preliminary study on joint injuries of anterior and calcaneal fibular ligaments of the lateral ankle joint, and to analyze mechanism of action of shaking and poking in treating ankle joint and biomechanical properties of ankle during the recovery of joint injuries. METHODS: CT scan was performed on a male volunteer with right ankle sprain. Mimics 10.0, Solidworks 2016, Hypermesh 12.0 and Abaqus 6.13 software were used to establish 3D nonlinear finite element analysis model of foot and ankle, and the validity of model was verified. Combined with clinical study, the finite element simulation analysis was carried out on the toe flexion, dorsiflexion, varus and valgus of ankle joint under different treatment periods by adjusting elastic modulus of ligament to simulate ligament injury. RESULTS: With the treatment of shake and prick and recovery of ligament injury, the maximum stress and area with large stress on tibial pitch and fibular joint surface gradually increased under the four working conditions, and the stress value of the maximum stress ligament gradually increased, and the stress of the anterior and calcaneal fibular ligament dispersed and transferred, and the axial force gradually decreased. CONCLUSION: The finite element method was used to simulate the mechanical condition of the shaking and stamping technique, and the changes of the forces of the ligament and articular surface before and after treatment of anterior and calcaneal ligament combined injury of ankle talus were intuitively observed. The treatment effect was quantified, and could provid objective and scientific basis for clinical promotion and application of this technique.

[Clinical observation of chiropractic manipulation in the treatment of degenerative scoliosis].

OBJECTIVE: To observe clinical efficacy of chiropractic manipulation in the treatment of degenerative scoliosis (DS). METHODS: From June 2017 to September 2019, 120 patients with degenerative scoliosis were randomly divided into treatment group (60 cases) and control group(60 cases). The patients in treatment group were treated with chiropractic manipulation once every other day for 4 weeks. The patients in control group were treated with eperisone hydrochloride tablets combined with thoracolumbar orthopedic(TSLO)brace, oral eperisone hydrochloride tablets 50 mg three times a day, wearing TSLO brace for not less than 8 hours a day. The course of treatment was 4 weeks. After the patients were selected into the group, visual analogue scale (VAS) and Oswestry Disability Index (ODI) were recorded before treatment, 1, 2, 3, 4 weeks after treatment and 1 month after treatment. The full length X-ray of the spine was taken before and 4 weeks after treatment, and the scoliosis Cobb angle, sagittal vertical axis (SVA) and lumbar lordosis (LL) were measured and compared. The adverse reactions during the treatment were recorded. RESULTS: There were significant differences in VAS and ODI between two groups at each time point after treatment (P<0.001), VAS and ODI at 2 weeks after treatment (PVAS=0.025, PODI=0.032) and 3 weeks after treatment(PVAS=0.040, PODI=0.044) in treatment group were significantly different from those in control group, but there was no significant difference in VAS and ODI at other time points between treatment group and control group (P>0.05). There was significant difference in Cobb angle between treatment group(P=0.010) and control group(P=0.017) after treatment, but there was no significant difference in LL and SVA between treatment group and control group. There was no significant difference in Cobb angle, LL and SVA between two groups before and after treatment. During the treatment, there were 4 mild adverse reactions in the control group and no adverse reactions in the treatment group. CONCLUSION: Chiropractic manipulation can effectively relieve pain and improve lumbar function in patients with degenerative scoliosis. The onset of action is faster than that oral eperisone hydrochloride tablets combined with TSLO brace, and it has better safety and can improve Cobb angle of patients with degenerative scoliosis.

[Influence of degenerative scoliosis on the treatment of lumbar spinal stenosis by MIS-TLIF].

OBJECTIVE: To evaluate the effect of degenerative scoliosis on the difficulty and efficacy of minimally invasive transforaminal lumbar interbody fusion(MIS-TLIF) in the treatment of lumbar spinal stenosis. METHODS: From September 2016 to September 2019, 52 patients with lumbar spinal stenosis treated by MIS-TLIF were retrospectively analyzed, including 16 males and 36 females, aged from 42 to 71(63.44±5.96) years old, the course of disease from 1.5 to 6.5 years, with an average of (3.69±1.10) years. All patients had lower extremity root pain or numbness, 41 patients had intermittent claudication. There were 31 cases of L4, 5 and 21 cases of L5S1. There were 18 cases in scoliosis group, lumbar spinal stenosis combined withdegenerative scoliosis, and 34 cases in stenosis group, lumbar spinal stenosis alone. The perioperative data and postoperative complications were recorded, the postoperative interbody fusion was evaluated by CT, and the clinical outcomes were evaluated by VAS score, Oswestry Disability Index (ODI). RESULTS: All patients were followed up for 12 to 36 months, with an average of (19.58±5.33) months. The operation time and intraoperative bleeding in stenosis group were better than those in scoliosis group (P<0.05). There were no significant differences in postoperative drainage volume, postoperative Hb, CRP, postoperative landing time, discharge time, VAS score at discharge and follow-up, ODI score at 3 months and follow up, postoperative complications and interbody fusion rate between two groups (P>0.05). CONCLUSION: For patients with lumbar spinal stenosis undergoing MIS-TLIF, degenerative scoliosis can lead to prolonged operation time and increased bleeding. However, it has no significant effect on therelief of postoperative symptoms, postoperative complications and the recovery of lumbar function.

Multifunctional modified polyvinyl alcohol: A powerful biomaterial for enhancing bioreactor performance in nitrate, Mn(II) and Cd(II) removal.

The co-existence of multiple pollutants in wastewater such as nitrate and heavy metal, is of high concern due to the potential environmental impact. In this study, a novel biomaterial PPy@Fe3O4/PVA was synthesized as a multifunctional bacteria immobilized carrier, to enhance simultaneous denitrification, Cd(II) and Mn(II) removal efficiency in bioreactor environments. The morphology and main components of the PPy@Fe3O4/PVA material were characterized by SEM and XRD. Using PPy@Fe3O4/PVA as a carrier, the maximum removal efficiencies for nitrate (0.207 mg L-1·h-1), Mn(II) (90.98%) and Cd(II) (98.78%) were increased by 27.05%, 30.27%, and 16.48%, respectively, compared to in the absence of PPy@Fe3O4/PVA. Regeneration experiments were performed, demonstrating the excellent stability and reusability of the PPy@Fe3O4/PVA material. Furthermore, effects of key factors were investigated on the performance of the PPy@Fe3O4/PVA bioreactor in simultaneous denitrification, Mn(II) and Cd(II) removal. Experimental results indicate that the highest nitrate, Mn(II) and Cd(II) removal efficiencies were obtained under the conditions of HRT of 10 h, initial Mn(II) concentration of 40 mg/L and initial Cd(II) concentration of 10 mg/L. Gas chromatography analysis indicated that N2 was the mainly final gaseous product. Moreover, the bioreactor community diversity was markedly influenced by the initial concentration of Cd(II) and Pseudomonas sp. H117 played a primary role in the process of simultaneous denitrification, Mn(II) and Cd(II) removal.

[Kinematic parameters and related influencing factors of sitting lumbar spine manipulation with motion capture].

OBJECTIVE: To explore the influence of individual characteristics of patients on the kinematics parameters of sitting lumbar spine manipulation. METHODS: From January 2016 to December 2016, 30 patients with degenerative lumbar spondylolisthesis were treatede, including 18 males and 12 females, aged from 45 to 61(52.33±2.34) years old, with a course of 2 to 72(29.13±3.23) months. Motion capture technique was used to measure the kinematics parameters of the same manipulator in sitting lumbar spine manipulation for 30 patients, including rotation time, maximum speed and maximum acceleration. The parameters of the left and right hands of the operator were different. The effects of individual characteristics on the kinematics parameters of sitting lumbar spine manipulation were analyzed. RESULTS: The kinematic and mechanical parameters of manipulation were as follows:spin time, maximum speed, maximum acceleration, the manipulation done by right or left hand showed the similar parameters(P>0.05). According to multivariate linear regression, there was a significant correlation between the age of the patient and the rotation time of the operator(P<0.01); the height of patient had a significant correlation with the maximum speed and maximum acceleration of the operator(P<0.01). CONCLUSIONS: There is no difference between the manipulation of left and right hand in clinical application. Age and height are important influencing factors of sitting lumbar rotation manipulation.

Performance and microbial community of simultaneous removal of NO3--N, Cd2+ and Ca2+ in MBBR.

A moving-bed biofilm reactor (MBBR) containing immobilized Acinetobacter sp.CN86 was operated to investigate the simultaneous denitrification, bio-mineralization and cadmium removal performance. Effects of hydraulic residence time (HRT) (4 h, 6 h and 8 h), pH (6.0, 7.0 and 8.0) and influent Cd2+ concentrations (10 mg/L, 30 mg/L and 50 mg/L) were assessed on the simultaneous removal of nitrate, Cd2+ and Ca2+. Results indicate that the highest pollutant removal efficiency (98.33% (1.866 mg/L·h) for NO3--N; 99.36% (1.242 mg/L·h) for Cd2+; 68.80% (15.480 mg/L·h) for Ca2+) was achieved under the conditions of a hydraulic residence time of 8 h, pH of 7.0 and initial Cd2+ concentration of 10 mg/L. Analyses of microbial distribution and community structures showed that Acinetobacter sp.CN86 was the main contributor (occupy 15.3% at the species level) to the effective removal of multiple pollutants in the MBBR. In addition, the main gas and precipitation components in the biofilm reactor were identified by gas chromatography, scanning electron microscope, and X-ray diffraction analyses.

Characterization of the Cd(II) and nitrate removal by bacterium Acinetobacter sp. SZ28 under different electron donor conditions.

In this study, zero-valent iron (ZVI), nanoscale zero-valent iron (nZVI), Fe(II), and Mn(II) were investigated for their effects on mixotrophic denitrification coupled with cadmium (Cd(II)) adsorption process by Acinetobacter sp. SZ28. The removal rates of nitrate were 0.228 mg L-1 h-1 (ZVI), 0.133 mg L-1 h-1 (nZVI), 0.309 mg L-1 h-1 (Fe(II)) and 0.234 mg L-1 h-1 (Mn(II)), respectively. The Cd(II) removal efficiencies were 97.23% (ZVI), 95.79% (nZVI), 80.63% (Fe(II)), and 84.58% (Mn(II)), respectively. Meteorological chromatography analysis indicated that the characteristics of gas composition were different under different electron donor conditions. Moreover, characterization of bacterial metabolites produced by strain SZ28 under different conditions was analyzed. Sequence amplification identified the presence of the nitrate reductase gene (napA) and Mn(II)-oxide gene (cumA) in strain SZ28. The results of XRD and SEM indicated that ZVI, nZVI, Fe(II), and Mn(II) were oxidized into corresponding oxides. XPS spectra indicated that the Cd(II) was adsorbed onto biogenic precipitation.

Analysis of the antimicrobial mechanism of porcine beta defensin 2 against E. coli by electron microscopy and differentially expressed genes.

Porcine beta defensin 2 (pBD2) is a cationic antimicrobial peptide with broad spectrum antibacterial activity, which makes it a potential alternative to antibiotics to prevent and cure diseases of pigs. However, development of pBD2 as an effective antibiotic agent requires molecular understanding of its functional mechanism against pathogens. In this study, we investigated the functional mechanism of pBD2 antibacterial activity. Escherichia coli was incubated with different pBD2 concentrations for different times. Electron microscopy was used to analyze the locations of pBD2 and its induced morphological changes in E. coli. Gene expression analysis was also performed to further understand the molecular changes of E. coli in response to pBD2 incubation. The results demonstrated that E. coli membranes were broken, holed, and wrinkled after treatment with pBD2, and pBD2 was located on the cell membranes and manly in the cytoplasm. Furthermore, 38 differentially expressed genes (DEGs) were detected, successfully sequenced and confirmed by quantitative real-time PCR (qRT-PCR). Most of the known functional DEGs were associated with DNA transcription and translation and located in the cytoplasm. Collectively, the results suggest that pBD2 could have multiple modes of action and the main mechanism for killing E. coli might be influence on DNA transcription and translation by targeting intracellular molecules after membrane damage, although transport and metabolism proteins were also affected.

[Analysis of X-ray signs of cervical spondylosis between vertebral artery type and radiculopathy].

OBJECTIVE: To improve the X-ray diagnosis of cervical spondylosis of vertebral artery type (VCS). METHODS: A blinded design research. The X-ray signs both 60 patients with VCS and 60 patients with cervical spondylotic radiculopathy were collected from January 2011 to November 2012. There were 36 males and 84 females, aged from 25 to 65 years old with an average of (48.4 ± 12.3) years old. Cervical curvature, atlanto-occipital joint angle, atlanto-axial joint angle, C2/C3 joint angle and lower cervical instability condition and segmental distribution were measured and recorded by X-rays. These data were analyzed and compared between the two groups after unblended. Combined with clinical manifestations,the X-ray imaging features of VCS were further analyzed. RESULTS: There was significant difference in cervical curvature between two groups in anteflexion X-ray films (P < 0.05). There was significant difference in extension degree of atlanto-occipital joint angle between two groups (P < 0.01). There was significant difference in atlanto-axial joint angle between two groups in lateral X-ray films (P< 0.05). There was significant.difference in anteflexion degree of atlanto-axial joint angle between two groups (P < 0.05). There was no significant difference in C2/C3 joint angle between two groups. There was no significant difference in the lower cervical instability condition and segmental distribution between two groups. In VCS group, the mild and moderate dizziness was main symptom, flexion and extension activities of neck was most common cause in the dizziness; and always accompanied with headache; tenderness mostly concentrated in the upper cervical area. CONCLUSION: Both X-ray signs and clinical manifestations can prompt the abnormalities of the upper cervical structure or function in patients with VCS. Anteflexion activities of neck observed by functional position of X-ray films should be emphasized in diagnosis of VCS.

Antimicrobial characterization of site-directed mutagenesis of porcine beta defensin 2.

Porcine ß defensin 2 (pBD2) is a small, cationic and amphiphilic antimicrobial peptide. It has broad antimicrobial activities against bacteria and plays an important role in host defense. In order to enhance its antimicrobial activity and better understand the effect of positively charged residues on its activity, we substituted eight amino acid residues with arginine or lysine respectively. All mutants were cloned and expressed in BL21 (DE3) plysS and the mutant proteins were then purified. These mutant versions had higher positive charges but similar structural configurations compared to the wild-type pBD2. Moreover, these mutant proteins showed different antimicrobial activities against E. coli and S. aureus. The mutant I4R of pBD2 had the highest antimicrobial activity. In addition, all the mutants showed low hemolytic activities. Our results indicated that the positively charged residues were not the only factor that influenced antimicrobial activity, but other factors such as distribution of these residues on the surface of defensins might also contribute to their antimicrobial potency.

[Study on meteorological factors-based neural network model of malaria].

OBJECTIVE: In order to provide reliable data for strategies development on prevention, a meteorological factors-based predicating model for malaria forecast was studied. METHODS: Data on malaria occurrence and climate changes from 1994 to 1999 in counties in Yunnan province was collected and analyzed with software packages of FoxPro 6.0 and Excel 5.0. The forecasting model for malaria occurrence was established, using the Neural Network Toolbox of Matlab 6.1 software package. In the studies of forecasting model, data of malaria and meteorological factors from 1994 to 1999 in Honghe state in Yunnan province was chosen. The meteorological factors included average monthly pressure, air temperature, relative humidity, monthly maximum air temperature, minimum air temperature, rainfall, rainday, evaporation and sunshine hours in the study. The established forecasting model was also tested and verified. RESULTS: The BP network model was established according to data of diseases and meteorological factors from Honghe state in Yunnan province. After training the neural network for 100 times, the error of performance decreased from 3.23608 to 0.035862. Verified by fact data of malaria, the efficiency of malaria forecasting was 84.85%. CONCLUSION: Neural network model was effective for forecasting malaria. It showed advantages as: strong ability for analysis, lower claim for data, convenient and easy to apply etc. Neural network model might be used as a new method for malaria forecasting.