A novel O-methyltransferase with substrate promiscuity from Ardisia japonica / 药学学报

italic>O-methyltransferases (OMTs) are one of the key tailoring enzymes in the biosynthesis of many natural products, O-methylation can not only reduce the reactivity of natural products, but also alter their solubility, stability and biological activities. Based on the transcriptome data of Ardisia japonica, a full-length cDNA sequence of candidate OMT (termed as AjOMT1) was cloned by reverse transcription-polymerase chain reaction (RT-PCR) and expressed in Escherichia coli (E. coli) for the first time. In vitro enzyme catalytic activity assay showed that the recombinant AjOMT1 could effectively catalyze quercetin to form O-methylated products. Most importantly, AjOMT1 showed unprecedented substrate promiscuity towards structurally various compounds including flavonoids, stilbenes, coumarins, alkaloids and phenylpropanoids, especially preferring to the compounds with adjacent phenolic hydroxyl groups, and showed regio-selectivity. These results suggested that AjOMT1 could be used as the tool enzyme to conduct O-methylation of different types of compounds to produce diverse active methylated products, and provide a new method for drug discovery, even universal part for synthetic biology of natural products.

Construction and application of recombinant human UDP-glucuronosyltransferases expression systems / 药学学报

In the research and development of new drugs, it is very important to investigate the in vitro metabolism of candidate drugs. Traditional models such as liver microsomes have many limitations, while the in vitro model of recombinant human drug metabolizing enzymes is considered as an important and useful approach because of its convenient access, stable activity and low cost. In this study, six major human UDP-glucuronosyltransferases (UGTs) genes (UGT1A1, 1A3, 1A4, 1A6, 1A9 and 2B7) were cloned from human liver cDNA and heterologously expressed in Saccharomyces cerevisiae and baculovirus-infected insect cell. UGT1A1, 1A3, 1A6 and 1A9 were successfully expressed in yeast and showed glucuronidation activity against a variety of different structural types of substrates, but their activities were low. All six UGTs were successfully expressed and exhibited significantly improved glucuronidation activity when Trichopolusia ni cells BTI-TN5B1-4 (High Five) were used as the host. The recombinant human UGTs expressed in insect cells can catalyze the glucuronidation of their specific substrates, and the glucuronidation products were synthesized at milligram-scale with yields of 13%-66% for the first time, of which the structures were identified via MS, 1H NMR, and 13C NMR spectroscopic analysis. Above all, the recombinant human UGTs yeast and insect cell expression systems constructed in this study can be used for in vitro metabolism evaluation in the early stage of new drugs research and development, and also provide a new tool for the synthesis of glucuronide metabolites.

Closed manipulative reduction and external fixation with cardboard splint for the treatment of Monteggia fracture / 中国骨伤

OBJECTIVE@#To explore clinical efficicacy of closed manipulative reduction and external fixation with cardboard splint in treating Monteggia fracture.@*METHODS@#Fifty-eight children with Monteggia fracture were underwent closed manipulative reduction and external fixation with cardboard splint from January 2010 to Junuary 2018. Among them, including 37 males and 21 females, aged from 3.5 to 12 years old with an average of (8.48±2.29) years old;the courses of disease ranged from 0.5 hours to 9 days with an average of (4.21±1.46) days. Broberg and Morrey scores before treatment, 1, 3 and 6 months after treatment were used to evaluate clinical effects.@*RESULTS@#All children were followed up from 1 to 6 months with an average of (3.35±2.12) months. Broberg and Morrey score (7.24±2.81) before treatment, (32.06 ±8.33) at 1 month after treatment, (73.18±5.56) at 3 months after treatment and (95.87±6.75) at 6 months after treatment; there were statistical differences at each time points after treatment with before treatment (@*CONCLUSION@#Treatment of Monteggia fractures with closed manipulative reduction and external fixation with cardboard splint could reach integration of motion and quietness, also could remove external fixation at early stage, and get obvious short-term and medium-term therapeutic results.

Enzymatic glycosylation of 4'-demethylepipodophyllotoxin / 中国中药杂志

The glycosides of 4'-demethylepipodophyllotoxin (DMEP) possess various pharmacological activities; however, the chemical synthesis of these glycosides faces challenges in regioselectivity, stereoselectivity, and the protection and de-protection of functional groups. In this work, a novel glycosyltransferase (GT) gene AbGT5 from Aloe barbadensis was successfully cloned, heterogeneously expressed and purified. Recombinant AbGT5 was able to catalyze the glycosylation of DMEP and the glycosylated product, which was separated from the preparative scale reaction, was characterized as DMEP 4'-O-β-D-glucoside via MS, 1H-NMR, 13C-NMR, HSQC and HMBC. According to the investigations of enzyme properties, AbGT5 show the highest activity around 20 ℃ in the buffer of pH 9.0, and it was independent of divalent metal ions. Under the optimum conditions, the conversion rate of DMEP can reach 80%. Above all, in this work the enzymatic glycosylation of DMEP was achieved with high efficiency by the novel GT AbGT5.

Cloning,expression and functional identification of secoisolariciresinol dehydrogenase gene from Dysosma versipellis callus / 中国中药杂志

Secoisolariciresinol dehydrogenase (SDH) is a key enzyme involved in the biosynthetic pathway of podophyllotoxin.In this study, two SDH candidate genes,SO282 and SO1223, were cloned from callus of Dysosma versipellis by homology-based PCR and rapid amplification of cDNA end (RACE).The SDH candidate genes were expressed in Escherichia coli and the subsequent enzyme assay in vitro showed that recombinant SO282 had the SDH activity. These results pave the way to the follow-up investigation of the biosynthetic of podophyllotoxin.

Manipulative reduction and external fixation with cardboard splint for the treatment of calcaneal fractures: a 60-case report / 中国骨伤

<p><b>OBJECTIVE</b>To investigate the therapeutic effects of manipulative reduction for calcaneal fractures.</p><p><b>METHODS</b>From January 2009 to June 2012, 53 cases (60 affected feet) of Sanders type I-IV calcaneal fractures were treated by manipulative reduction and external fixation with cardboard splint,including 45 males and 8 females with an average age of (33.5 +/- 1.54) years old ranging from 18 to 65. The course of disease ranged 0.5 h to 7 d. Before treatment the feet were swelling, ache and activity limitation in evidence, some feet were wide flat deformity, the cortical bone was broken in the imaging examination. All selected cases were evaluated using Creighton-Nebraska health foundation assessment scale for fractures of calcaneus.</p><p><b>RESULTS</b>All cases were followed up at 12 months after treatment, 13 feet got excellent curative effect, 34 good, 11 moderate and 2 poor.</p><p><b>CONCLUSION</b>Manipulative reduction for Sanders type I-IV calcaneal fractures could get excellent curative effect. Manipulative reduction for calcaneal fractures could avoid surgical trauma while assure high curative effects. Manipulative reduction is not only economical and easy therapy, but also can restore maximum function of the calcaneus with few complications and facilitate early rehabilitation of ankle and joint function.</p>

Manipulative reduction with minimally invasive percutaneous plate osteosynthesis for 60 patients with distal tibiofibular fractures / 中国骨伤

<p><b>OBJECTIVE</b>To explore clinical effects of manipulative reduction with minimally invasive percutaneous plate osteosynthesis in treating distal tibiofibular fractures.</p><p><b>METHODS</b>From 2009 to 2011, 60 patients with distal tibiofibular fractures were treated by manipulative reduction with minimally invasive percutaneous plate osteosynthesis. Among them, there were 32 males and 28 females aged from 14 to 70 years old with an average of 41.22 +/- 2.06. According to AO classification of fractures,5 cases were type A1, 22 cases were type A2,21 cases were type A3 and 12 cases were type C1. Operation time, blood loss,time of callus and fracture healing were observed, Mazur scoring of ankle joint were used to evaluate therapeutic.</p><p><b>RESULTS</b>Fifty-eight incisions were healed at stage I ,and 2 cases were infected at distal tibial. Operation time was with an average of (62.34 +/- 5.66) min ranged 45 to 90 min;blood loss was 30 to 150 ml with an average of (80.57 +/- 5.59) ml;formation of callus appeared from 4 to 12 weeks,with an average of (8.24 +/- 2.06) weeks, and fracture healing time was from 3 to 6 months, with an average of (4.50 +/- 1.13) months. According to Mazur scoring of ankle joint 40 cases got excellent results, 18 good, and 2 fair.</p><p><b>CONCLUSION</b>Manipulative reduction with minimally invasive percutaneous plate osteosynthesis can obtain reliable fixation. It is a good choice of treating distal tibiofibular fractures by protecting blood supply of fractures.</p>

Sulfation of naringenin by Mucor sp / 中国中药杂志

Naringenin (1) was transformed to three metabolites (2-4) by Mucor sp. Based on LCMS(n)-IT-TOF and NMR spectroscopic data, 2-4 were identified as naringenin-7-O-sulphate, naringenin-4'-O-sulphate, and naringenin-5-O-sulphate, respectively. These results might provide hints to the mammalian/human metabolism of naringenin.