Efficient molasses utilization for low-molecular-weight poly-γ-glutamic acid production using a novel Bacillus subtilis stain.

BACKGROUND: Poly-γ-glutamic acid (γ-PGA) is a biopolymer and has various applications based on its biocompatibility, non-toxicity, and edibility. Low-molecular-weight (Mw)-γ-PGA has promising applications in agriculture and pharmaceuticals. It is traditionally produced by enzymatic hydrolysis. Cost-effective bioproduction of low-Mw-γ-PGA is essential for commercial application of γ-PGA. RESULTS: Bacillus subtilis 242 is a newly isolated low-Mw-γ-PGA-producing strain. To develop cost-effective production of γ-PGA using this newly isolated strain, cane molasses and corn steep liquor were used to produce γ-PGA. The concentration of cane molasses was optimized and 100 g/L cane molasses resulted in high γ-PGA production. The effects of yeast extract and corn steep liquor on γ-PGA yield were investigated. High concentration of γ-PGA was obtained in the medium with corn steep liquor. A concentration of 32.14 g/L γ-PGA was achieved in fed-batch fermentation, with a productivity of 0.67 g/L/h and a percentage yield (gγ-PGA/gglutamate) of 106.39%. The Mw of γ-PGA was 27.99 kDa. CONCLUSION: This study demonstrated the potential application of B. subtilis 242 for cost-effective production of low-Mw-γ-PGA from cane molasses.

Development of a Conjugation-Based Genome Editing System in an Undomesticated Bacillus subtilis Strain for Poly-γ-glutamic Acid Production with Diverse Molecular Masses.

Poly-γ-glutamic acid (γ-PGA) is a biodegradable polymer produced by microorganisms. Biosynthesizing γ-PGA with diverse molecular masses (Mw) is an urgent industrial technical problem to be solved. Bacillus subtilis KH2, a high-Mw γ-PGA producer, is an ideal candidate for de novo production of γ-PGA with diverse Mw values. However, the inability to transfer DNA to this strain has limited its industrial use. In this study, a conjugation-based genetic operating system was developed in strain KH2. This system enabled us to modify the promoter of γ-PGA hydrolase PgdS in strain KH2 chromosome to de novo biosynthesize γ-PGA with diverse Mws. The conjugation efficiency was improved to 1.23 × 10-4 by establishing a plasmid replicon sharing strategy. A further increase to 3.15 × 10-3 was achieved after knocking out two restriction endonucleases. To demonstrate the potential of our newly established system, the pgdS promoter was replaced by different phase-dependent promoters. A series of strains producing γ-PGA with specific Mws of 411.73, 1356.80, 2233.30, and 2411.87 kDa, respectively, were obtained. The maximum yield of γ-PGA was 23.28 g/L. Therefore, we have successfully constructed ideal candidate strains for efficient γ-PGA production with a specific Mw value, which provides an important research basis for sustainable production of desirable γ-PGA.

Cost and Effectiveness of Percutaneous Endoscopic Interlaminar Discectomy versus Microscope-Assisted Tubular Discectomy for L5-S1 Lumbar Disc Herniation.

OBJECTIVE: To assess the cost and effectiveness of percutaneous endoscopic interlaminar discectomy (PEID) and microscope-assisted tubular discectomy (MATD) for patients with L5/S1 lumbar disc herniation (LDH). METHODS: The medical and financial records of patients diagnosed with L5/S1 LDH and who underwent either PEID or MATD from April 2021 to April 2022 were retrospectively collected. Demographic and baseline information, perioperative observational index, clinical outcomes, and inpatient costs were analyzed. RESULTS: Sixty patients were included, with 30 patients in the PEID group and 30 patients in the MATD group. No significant difference was found in demographic and baseline information between the 2 groups (P > 0.05). The PEID group showed significantly shorter incision length, less intraoperative blood loss, shorter hospital stays, and higher intraoperative fluoroscopy frequency compared with the MATD group (P < 0.05). There were no significant differences in visual analog scale back/leg score, Oswestry Disability Index, and 36-Item Short-Form Survey score between PEID and MATD groups before the surgery and at any follow-up time points (P > 0.05). The total cost, surgery cost, and surgical instruments/materials cost were significantly higher in the PEID group compared with the MATD group (P < 0.05). In contrast, the drug and nursing costs were significantly higher in the MATD group than in the PEID group (P < 0.05). CONCLUSIONS: PEID and MATD provide equivalent clinical efficacy and safety in treating LDH at L5/S1 segment within a 1-year follow-up. However, PEID is less invasive and MATD is less costly. No one surgical technique is superior in all aspects and patients should make decisions according to their top concern.

Rapid adaptive evolution of Bacillus coagulans to undetoxified corncob hydrolysates for lactic acid production and new insights into its high phenolic degradation.

Here, an adapted Bacillus coagulans (Weizmannia coagulans) strain CC17B-1 was developed for lignocellulosic lactic acid production through a short and rapid adaptive laboratory evolution technique. Without any detoxification, two actual corn cob hydrolysates from the factory were effectively fermented to lactic acid within 60 h. Strain CC17B-1 is capable of degrading all nine determined phenolic compounds in the hydrolysate, with the only exception being vanillic acid. Notably, its tolerances for ferulic acid and p-coumaric acid are the highest doses reported in anaerobic microbes. A proposed degradation pathway showed that strain CC17B-1 could convert phenolic aldehydes to phenolic alcohol and then further degrade them completely. This work provides new ideas for the microbe phenolic degradation pathway and paves the way for industrial lactic acid production from lignocellulosic biomass.

An injectable pH neutral bioactive glass-based bone cement with suitable bone regeneration ability.

Background: As a class of promising bone augmentation materials, bone cements have attracted particular attention. Due to various limitations, the current bone cements are still imperfect. In this study, an injectable pH neutral bioactive bone cement (PSC/CSC) was developed by mixing phosphosilicate bioactive glass (PSC) and α-calcium sulfate hemihydrate (CSH), with the goal of optimizing bone defects repairs. Methods: A range of compositions (PSC/CSC: 10P/90C, 30P/70C, 50P/50C) were developed and their physicochemical properties evaluated. Their bone regeneration ability was compared to those of two widely used bone cements as controls (calcium phosphate cement (CPC) and Genex®) in rabbit femoral condyle bone defect models for 4, 8 and 12 weeks. Based on physicochemical properties and in vivo bone regeneration ability, the PSC/CSC exhibited the best outcomes was selected. Then, in vitro, the effects of selected PSC/CSC, CPC and Genex® extracts on MC3T3-E1 cell proliferation, migration and osteogenesis as well as angiogenesis of HUVECs were examined. Results: Based on physicochemical properties, the 30P/70C formula exhibited suitable operability and compressive strength (3.5 ±â€¯0.3 MPa), which fulfilled the requirements for cancellous bone substitutes. In vivo, findings from micro-CT and histological analyses showed that the 30P/70C formula better promoted bone regeneration, compared to 10P/90C, 50P/50C, CPC and Genex®. Hence, 30P/70C was selected as the ideal PSC-based cement. In vitro, the 30P/70C extracts showed better promotion of cell viability, alkaline phosphatase (ALP) activity, calcium mineral deposition, mRNA and protein expression levels of osteogenesis in MC3T3-E1 cells, further supporting its superiority. Meanwhile, the 30P/70C extracts also showed better stimulation of HUVECs proliferation and angiogenesis. Conclusion: The new composite cement, 30P/70C, is a favorable bioactive glass-based bone cement with suitable operability, compressive strength and bone regeneration ability. The translational potential of this article: Clinically, treatment of large bone defects is still a major challenge for orthopaedic trauma. We showed that 30P/70C has the potential to be clinically used as an injectable cement for rapid bone repairs and reconstruction of critical sized bone defects.

mTORC1 coordinates NF-κB signaling pathway to promote chondrogenic differentiation of tendon cells in heterotopic ossification.

Heterotopic ossification (HO) is a pathological bone formation based on endochondral ossification distinguished by ossification within muscles, tendons, or other soft tissues. There has been growing studies focusing on the treatment with rapamycin to inhibit HO, but the mechanism of mTORC1 on HO remains unclear. Tendon cells (TDs) are the first cells to form during tendon heterotopic ossification. Here, we used an in vivo model of HO and an in vitro model of chondrogenesis induction to elucidate the effect and underlying mechanism of mTORC1 in HO. The current study highlights the effect of rapamycin on murine Achilles tenotomy-induced HO and the role of mTORC1 signaling pathway on TDs. Our result showed that mTORC1 was activation in the early stage of HO, whereas the mTORC1 maintained low expression in the mature ectopic cartilage tissue and the ectopic bone formation sites. The use of mTORC1-specific inhibitor (rapamycin) immediately after Achilles tendon injury could suppress the formation of HO; once ectopic cartilage and bone had formed, treatment with rapamycin could not significantly inhibit the progression of HO. Mechanistically, mTORC1 stimulation by silencing of TSC1 promoted the expression of the chondrogenic markers in TDs. In TDs, treated with mTORC1 stimulation by silencing of TSC1, mTORC1 increased the activation of the NF-κB signaling pathway. NF-κB selective inhibitor BAY11-7082 significantly suppressed the chondrogenesis of TDs that treated with mTORC1 stimulation by silencing of TSC1. Together, our findings demonstrated that mTORC1 promoted HO by regulating TDs chondrogenesis partly through the NF-κB signaling pathway; and rapamycin could be a viable HO therapeutic regimen.

The efficacy and safety of Xuebijing injection for corona virus disease 2019: A protocol for a systematic review and meta-analysis.

BACKGROUND: Corona virus disease 2019 (COVID-19) is an epidemic respiratory infectious disease caused by Severe Acute Respiratory Syndrome Coronavirus 2 infection. Now it is popular all over the world on a large scale. COVID-19 has the characteristics of rapid transmission, atypical clinical symptoms, easy missed diagnosis and misdiagnosis, and so on. which has seriously affected social and economic development and people's health. Severe acute respiratory syndrome corona virus type 2 infection may lead to systemic cytokine storm, which leads to a sharp deterioration of the condition of ordinary patients. At present, no specific drug has been found in the clinical treatment of covid-19, while Xuebijing injection has been widely used in severe patients in China as a traditional Chinese medicine. The aim of this study is to assess the effificacy and safety of Xuebijing injection for COVID-19. METHODS: Before the research, we conducted a comprehensive search on relevant websites. Two professional researchers will gradually screen, read the title, abstract and full text if necessary, and independently select qualified documents according to the inclusion and exclusion criteria. We will conduct a meta-analysis of the results related to COVID-19 to assess the risks of bias and data extraction. The heterogeneity of data will be studied by Cochrane X and I tests. The evaluation of publication bias will be carried out by funnel chart analysis and Eger test. RESULTS: This review will be disseminated in print by peer-review. CONCLUSION: Our research is to scientifically analyze the clinical evidence of Xuebijing injection in treating severe COVID-19 patients.

[Comparison Test Between On-line Monitoring of Water-soluble Ions and Filter-based Manual Methods for PM2.5].

Concentrations of water-soluble ions were measured in Beijing during 2014 for comparison of URG online monitoring systems and filter-based manual methods. The differences of four main ions components in spring, summer, autumn and winter were compared. The total concentrations of eight ions measured by URG online were higher than those of filter-based manual method. There was no significant differences among the annual concentrations of Cl-,NO3-,Mg2+ and Ca2+ obtained by the two methods, while the concentrations of SO42-,NH4+,Na+,K+ from online were higher than those from filter. NO3-,SO42-,Cl- had good correlations in autumn and winter, and NH4+ only had better fitting performance in winter.

[Characteristics of Ozone Background Concentration in Beijing from 2004 to 2015].

Based on the hourly O3 monitoring data from 2004 to 2015 of Beijing, a comprehensive discussion on the characteristics of O3 concentration at a background station Dingling in Beijing was conducted. The results showed that the annual concentration of O31h was increasing with a growth rate of 4.40 µg·m-3 while the annual concentration of O38h was decreasing with annual average rates of -1.0 µg·m-3 and -1.5 µg·m-3 from May to October in 2004 and 2015. Over the past 3 years, number of O38h severe pollution days increased significantly and the situation of O3 pollution in Beijing became more serious. O3 concentration reached its peak in June in a year and its diurnal peak concentration occurred at about 15:00-18:00 at Dingling station which was 101-1.56 times larger than that in the urban center of Beijing. In different years, the ozone peak concentration at Dingling Station was 1h later than that in the urban center from May to October in diurnal variation and the difference of peak concentration was significantly reduced in recent years, which on the one hand may be related to regional ozone pollution, on the other hand may be related to the expansion of Beijing's urbanization.

[Characterization of Water-soluble Ions in PM2.5 of Beijing During 2014 APEC].

The mass concentration of PM2.5 associated with its online and off-line water-soluble ions were obtained during 2014- 10- 2014-11. Secondary inorganic species NO3⁻, SO4²â» and NH4⁺ were the major components of PM2.5 during different observation periods. The total concentration of NO3⁻, SO4²â» and NH4⁺ was (26.8 ± 22.5) µg · m⁻³, which contributed (41.7 ± 8.5)% to PM2.5. The concentration of NO3⁻ was higher than those of others and contributed most to PM2.5. The ions of NO3⁻, SO4²â» NH4⁺ and Cl⁻ all showed three different periods during 2014 Beijing APEC, besides the different meteorological condition, the cumulative effect caused by local emissions and regional pollution could also not be ignored. Although the characteristics of water-soluble ions was different during different observation periods, there was no obvious acidification of PM2.5 in Beijing at the end of autumn and beginning of winter.