Modification of C20 oxidase in tanshinone biosynthesis pathway / 中国中药杂志

Tanshinones are one of the main effective components of Salvia miltiorrhiza, which play important roles in the treatment of cardiovascular diseases. Microbial heterogony production of tanshinones can provide a large number of raw materials for the production of traditional Chinese medicine(TCM) preparations containing S. miltiorrhiza, reduce the extraction cost, and relieve the pressure of clinical medication. The biosynthetic pathway of tanshinones contains multiple P450 enzymes, and the catalytic element with high efficiency is the basis of microbial production of tanshinones. In this study, the protein modification of CYP76AK1, a key P450-C20 hydroxylase in tanshinone pathway, was researched. The protein modeling methods SWISS-MODEL, Robetta, and AlphaFold2 were used, and the protein model was analyzed to obtain the reliable protein structure. The semi-rational design of mutant protein was carried out by molecular docking and homologous alignment. The key amino acid sites affecting the oxidation activity of CYP76AK1 were identified by molecular docking. The function of the obtained mutations was studied with yeast expression system, and the CYP76AK1 mutations with continuous oxidation function to 11-hydroxysugiol were obtained. Four key amino acid sites that affected the oxidation acti-vity were analyzed, and the reliability of three protein modeling methods was analyzed according to the mutation results. The effective protein modification sites of CYP76AK1 were reported for the first time in this study, which provides a catalytic element for different oxidation activities at C20 site for the study of the synthetic biology of tanshinones and lays a foundation for the analysis of the conti-nuous oxidation mechanism of P450-C20 modification.

Cloning and functional characterization of isopentenyl diphosphate isomerase genes from Panax vietnamensis var. fuscidiscus / 药学学报

Isopentenyl diphosphate isomerase (IDI) is a key enzyme in the regulation of triterpenes biosynthesis and plays an important role in ginsenoside biosynthesis. In this study, two IDI genes, PvfIDI1 (GenBank No. MZ736417) and PvfIDI2 (GenBank No. MZ736418) were cloned from Panax vietnamensis var. fuscidiscus. The open reading frame of both PvfIDI1 and PvfIDI2 was 924 bp encoding 307 amino acids. The molecular weights of PvfIDI1 and PvfIDI2 were 34.84 kDa and 34.66 kDa, respectively, with theoretical pIs of 6.01 and 5.66. Bioinformatic analysis indicated that PvfIDI1 and PvfIDI2 contained two conserved sequences: TNTCCSHPL and WGEHELDY. Phylogenetic analysis showed that PvfIDI1 and PvfIDI2 were closely related to Panax notoginseng IDI. Expression analysis showed that both PvfIDI1 and PvfIDI2 genes are expressed in root, rhizome, stem and leaf of P. vietnamensis var. fuscidiscus. However, PvfIDI1 is highly expressed in the rhizome and PvfIDI2 is highly expressed in the stem. PvfIDI1 and PvfIDI2 recombinant proteins were expressed in E. coli; a functional coloration experiment showed that PvfIDI1 and PvfIDI2 could promote the accumulation of lycopene, indicating that both PvfIDI1 and PvfIDI2 encode functional IDI enzymes. The cloning and functional studies on PvfIDI1 and PvfIDI2 provide a foundation for the further study of IDI and the regulation of ginsenoside biosynthesis in P. vietnamensis var. fuscidiscus.

Selection of optimal qRT-PCR reference genes for Aconitum vilmorinianum / 中国中药杂志

Screening suitable reference genes is the premise of quantitative Real-time PCR(qRT-PCR)for gene expression analysis. To provide stable reference genes for expression analysis of genes in Aconitum vilmorinianum, this study selected 19 candidate re-ference genes(ACT1, ACT2, ACT3, aTUB1, aTUB2, bTUB, 18S rRNA, UBQ, eIF2, eIF3, eIF4, eIF5, CYP, GAPDH1, GAPDH2, PP2A1, PP2A2, ACP, and EF1α) based on the transcriptome data of A. vilmorinianum. qRT-PCR was conducted to profile the expression of these genes in the root, stem, leaf, and flower of A. vilmorinianum. The Ct values showed that 18S rRNA with high expression level and GAPDH2 with large expression difference among organs were not suitable as the reference genes. NormFinder and geNorm showed similar results of the expression stability of the other candidate reference genes and demonstrated PP2A1, EF1α, and CYP as the highly stable ones. However, BestKeeper suggested EF1α, ACT3, and PP2A1 as the top stable genes. In view of the different results from different softwares, the geometric mean method was employed to analyze the expression stability of the candidate re-ference genes, the results of which indicated that PP2A1, EF1α, and ACT3 were the most stable. Based on the comprehensive analysis results of geNorm, NormFinder, BestKeeper, and geometric mean method, PP2A1 and EF1α presented the most stable expression in different organs of A. vilmorinianum. PP2A1 and EF1α were the superior reference genes for gene expression profiling in different organs of A. vilmorinianum.

CT axial imaging of the iliolumbar ligament and its significance on locating lumbosacral vertebral segments / 中国骨伤

<p><b>OBJECTIVE</b>To study the CT axial manifestations of iliolumbar ligament(ILL) and discusses its clinical effects on locating lumbosacral vertebral segments.</p><p><b>METHODS</b>From May 2008 to March 2010, 706 adult patients diagnosed lumbar disc disease were performed with axial scans by single slice helical CT. Among the patients, 436 patients were male and 270 patients were female, ranging in age from 25 to 82 years, the median age was 44 years, 78 cases with lumbosacral transitional vertebrae (LSTV) were verified by X-radiography or fluoroscopy. The morphology, origin and insertion, courses of ILL and the relationship of ligament and spinal segments on axial plane images were used to study. The location method of spinal segments by ILL was compared with the other four location methods on CT.</p><p><b>RESULTS</b>Of the 628 cases with normal lumbosacral segmentations sides of ligament, the main part of ILL originated from L5 transverse processes and terminated at the iliac crest, the morphological characters were divided into two types: double band (71.8%, 451/628) and single band (28.2%, 177/628). The tiny branches from posterior and outside edge of L4, lumbar disc were seen simultaneity in 3 cases. The ILL of 78 cases with LSTV all also originated from L5 transverse processes. Using ILL as a marker of the L5 vertebral level, 78 cases with LSTV were correctly numbered, the accuracy rate was higher than the other location methods, there was statistical significance between the location method by ILL and the location method by iliac crest (P < 0.05).</p><p><b>CONCLUSION</b>The main part of ILL originates from L5 transverse processes, the anatomic location is relatively steady and can be clearly displayed on axial CT, which can be used as a measure in the idenlification of LSTV in clinical practice, it is worthy to be applied widely in basic-level hospitals.</p>