Highly efficient bio-production of putrescine from L-arginine with arginase and L-ornithine decarboxylase in engineered Escherichia coli.

To achieve industrial-scale putrescine production, a high efficient bio-synthesis of putrescine involving arginase (ARG, EC 3.5.3.1) and L-ornithine decarboxylase was evaluated here. Among the four arginases tested, ARGBT from Bos Taurus showed the highest activity (1966 U/mg). Compared to the L-arginine decarboxylase (ADC) pathway, the strain expressing ARGBT and L-ornithine decarboxylase (SpeC) produced 28.7 g/L putrescine, a 38.6 % increase. Two pyridoxal phosphate (PLP) salvage pathways were evaluated, and the strain BL-PTac-PdxK co-expressed pyridoxal kinase (PdxK) performed better. D-Glucose was used as the co-substrate to improve the putrescine titer further. Under optimal conditions, 43.6 g/L putrescine was produced from 87.1 g/L L-arginine, and 76 g/L putrescine was synthesized on a 0.5 L scale. Using L-arginine fermentation broth (60 g/L) as the substrate, a titer of 30 g/L putrescine was achieved. This efficient biotransformation process presented here enables feasible industrial-scale putrescine production.

Efficacy and safety of brivudine for the treatment of herpes zoster: a systematic review and meta-analysis.

BACKGROUND AND OBJECTIVE: Brivudine has been used in herpes zoster (HZ) treatment for years, but the safety and efficacy of brivudine are inconclusive. Here we perform a meta-analysis to assess the efficacy, safety, incidence of postherpetic neuralgia of brivudine. METHODS: Data of randomized controlled Trials (RCTS) were obtained from the databases of both English (PubMed, Embase, and Cochrane Library) and Chinese (China National Knowledge Infrastructure, China Science Journal Database, and WanFang Database) literatures from inception to 12 September 2022. Meta-analyses of efficacy and safety of Brivudine for the treatment of herpes zoster for RCTS were conducted. RESULTS: The analyses included seven RCTS (2095 patients in experimental group and 2076 patients in control group) in the treatment of HZ with brivudine. It suggested that the brivudine group was superior to the control group in terms of efficacy (p = .0002) and incidence of postherpetic neuralgia (p = .04). But the incidence of adverse reactions has no significant difference between the brivudine and the control groups (p = .22). In addition, subgroup analysis of adverse events also showed that brivudine was about the same safety as other modalities in the treatment of HZ (p > .05). CONCLUSIONS: Brivudine is effective for HZ. However, the evidence on the safety of brivudine is insufficient.

Application of a modified tetra-primer ARMS-PCR assay for rapid Panax species identity authentication in ginseng products.

Panax ginseng products can be adulterated with materials from other Panax species. The purpose of this study is to provide a rapid P. ginseng authentication method for simultaneous identification of P. ginseng and detection of adulteration in ginseng products at different processing stages. First, a tetra-primer ARMS-PCR assay was designed based on a single-nucleotide polymorphism (SNP) within the trnL-trnF region and was tested at 28 PCR cycles with DNA extracted from Botanical Reference Materials (BRMs). Next, 5' end random nucleotide and 3' terminus phosphorothioates linkage modifications were incorporated into the inner primers to improve sensitivity and specificity at 40 PCR cycles. Finally, the modified assay was validated using characterized market ginseng materials and the detection limit was determined. The modified tetra-primer ARMS-PCR assay can achieve the desired sensitivity and specificity using one set of reaction conditions in ginseng materials at different stages. In validation, it was able to correctly identify target species P. ginseng and differentiate it from closely related species. This study suggests that the modified tetra-primer ARMS-PCR assay can be used for the rapid, species identity authentication of P. ginseng material in ginseng products. This assay can be used to complement chemical analytical methods in quality control, so both species identity and processing attributes of ginseng products can be efficiently addressed.

The roles of the Hippo-YAP signalling pathway in Cartilage and Osteoarthritis.

Osteoarthritis (OA) is an age-related disease, characterized by cartilage degeneration. The pathogenesis of OA is complicated and the current therapeutic approaches for OA are limited. Cartilage, an integral part of the skeletal system composed of chondrocytes, is essential for skeletal development, tissue patterning, and maintaining the normal activity of joints. The development, homeostasis and degeneration of cartilage are tightly associated with OA. Over the past decade, accumulating evidence indicates that Hippo/YAP is a vital biochemical signalling pathway that strictly governs tissue development and homeostasis. The joint tissues, especially for cartilage, are sensitive to changes of Hippo/YAP signalling. In this review, we summarize the role of Hippo/YAP signalling in cartilage and discuss its involvement in OA progression from points of cartilage degradation, subchondral bone remodeling, and synovial alteration. We also highlight the potential therapeutic implications of Hippo/YAP signalling and further discuss current limitations and controversy on Hippo/YAP-based application for OA treatment.

High-Coverage Reconstruction of XCO2 Using Multisource Satellite Remote Sensing Data in Beijing-Tianjin-Hebei Region.

The extreme climate caused by global warming has had a great impact on the earth's ecology. As the main greenhouse gas, atmospheric CO2 concentration change and its spatial distribution are among the main uncertain factors in climate change assessment. Remote sensing satellites can obtain changes in CO2 concentration in the global atmosphere. However, some problems (e.g., low time resolution and incomplete coverage) caused by the satellite observation mode and clouds/aerosols still exist. By analyzing sources of atmospheric CO2 and various factors affecting the spatial distribution of CO2, this study used multisource satellite-based data and a random forest model to reconstruct the daily CO2 column concentration (XCO2) with full spatial coverage in the Beijing-Tianjin-Hebei region. Based on a matched data set from 1 January 2015, to 31 December 2019, the performance of the model is demonstrated by the determination coefficient (R2) = 0.96, root mean square error (RMSE) = 1.09 ppm, and mean absolute error (MAE) = 0.56 ppm. Meanwhile, the tenfold cross-validation (10-CV) results based on samples show R2 = 0.91, RMSE = 1.68 ppm, and MAE = 0.88 ppm, and the 10-CV results based on spatial location show R2 = 0.91, RMSE = 1.68 ppm, and MAE = 0.88 ppm. Finally, the spatially seamless mapping of daily XCO2 concentrations from 2015 to 2019 in the Beijing-Tianjin-Hebei region was conducted using the established model. The study of the spatial distribution of XCO2 concentration in the Beijing-Tianjin-Hebei region shows its spatial differentiation and seasonal variation characteristics. Moreover, daily XCO2 map has the potential to monitor regional carbon emissions and evaluate emission reduction.

Effect of Hydrophobic Groups on Antimicrobial and Hemolytic Activity: Developing a Predictive Tool for Ternary Antimicrobial Polymers.

Antimicrobial polymers have emerged as a potential solution to the growing problem of antimicrobial resistance. Although several studies have examined the effects of various parameters on the antimicrobial and hemolytic activity of statistical copolymers, there are still numerous parameters to be explored. Therefore, in this study, we developed a library of 36 statistical amphiphilic ternary copolymers prepared via photoinduced electron transfer-reversible addition-fragmentation chain transfer polymerization to systematically evaluate the influence of hydrophobic groups [number of carbons (5, 7, and 9)] and chain type of the hydrophobic monomer (cyclic, aromatic, linear, or branched), monomer ratio, and degree of polymerization (DPn) on antimicrobial and hemolytic activity. To guide our synthetic strategy, we developed a pre-experimental screening approach using C log P values of oligomer models, which correspond to the logarithm of the partition coefficient of compounds between n-octanol and water. This method enabled correlation of polymer hydrophobicity with antimicrobial and hemolytic activity. In addition, this study revealed that minimizing hydrophobicity and hydrophobic content were key factors in controlling hemolysis, whereas optimizing antimicrobial activity was more complex. High antimicrobial activity required hydrophobicity (i.e., C log P, hydrophobicity index) that was neither too high nor too low, an appropriate cationic/hydrophobic balance, and structural compatibility between the chosen monomers. Furthermore, these findings could guide the design of future antimicrobial ternary copolymers and suggest that C log P values between 0 and 2 have the best balance of high antimicrobial activity and low hemolytic activity.