Hepatic pathological characteristics and factors influencing alanine transaminase value below twice the upper limit of normal in patients with chronic hepatitis B / 中华肝脏病杂志

Objective: To analyze the hepatic pathological characteristics and factors influencing an alanine transaminase value below twice the upper limit of normal in patients with chronic hepatitis B (CHB) and further explore the optimal ALT threshold strategy for initiating antiviral therapy. Methods: Clinical data of treatment-naïve CHB patients who underwent liver biopsies from January 2010 to December 2019 were retrospectively collected. Multiple regression models were used to explore the ALT levels and significant risk of hepatic histological changes (≥G2/S2). Receiver operating characteristic curve was used to evaluate the value of different models in diagnosing liver tissue inflammation≥G2 or fibrosis ≥ S2. Results: A total of 447 eligible CHB patients, with a median age of 38.0 years and 72.9% males, were included. During ALT normalization, there was significant liver inflammation (≥G2) and fibrosis (≥S2) in 66.9% and 53.0% of patients, respectively. With an ALT rise of 1-2×ULN, the proportions of liver inflammation≥G2 and fibrosis≥S2 were 81.2% and 60.0%, respectively. After adjusting for confounding factors, higher ALT levels (> 29 U/L) were found to be associated with significant liver inflammation (OR: 2.30, 95% CI: 1.11 ~ 4.77) and fibrosis (OR: 1.84, 95% CI: 1.10 ~ 3.09). After the measurement of glutamyltransferase-platelet ratio (GPR), the proportion of CHB patients with≥G2/S2 was significantly reduced under different treatment thresholds of ALT standards, and in particular, the erroneous evaluation of liver fibrosis≥S2 was significantly improved (33.5% to 57.5%). Conclusion: More than half of CHB patients have a normal ALT or one within 2 × ULN, regardless of whether or not there is apparent inflammation and fibrosis. GPR can significantly improve the precise assessment of different conditions of treatment thresholds for the ALT value in CHB patients.

Prokaryotic expression, function verification and immunoassay activity of farnesyl pyrophosphate synthase of Alisma orientale (Sam.) Juzep / 药学学报

Farnesyl pyrophosphate synthase of Alisma orientale (Sam.) Juzep. (AoFPPS) is considered as one of the important rate-limiting enzymes in the biosynthetic pathway of protostane triterpenes. In order to investigate the expression and function of AoFPPS, the gene (accession No. HQ724508) was cloned into a bacterial expression vector pCzn1, then the combined plasmid pCzn1-AoFPPS was transformed into Escherichia coli BL21, and a fusion protein was obtained after induction. The fusion protein was purified by Ni resin, and the function was verified through in vitro enzymatic reaction. High performance liquid chromatography (HPLC) analysis revealed that the products were able to catalyze the synthesis of farnesyl pyrophosphate (FPP). High purity recombinant protein was used to immunize New Zealand rabbits to generate a polyclonal antibody. The titer of the antibody was determined by enzyme linked immunosorbent assay (ELISA), and Western blot results demonstrated that the antibody could specifically recognize the AoFPPS protein in A. orientale (Sam.) Juzep. So,the method of rapid immunoassay to detect AoFPPS was established. This study lays the foundation for further study of the AoFPPS gene expression, regulation and mechanism of action in A. orientale (Sam.) Juzep., and it also provides a scientific basis on improving the quality of Alismatis Rhizoma using the plant genetic engineering.

Cloning and expression analysis in resurrection process of trehalose-6-phosphate synthase gene from Selaginella tamariscina / 中国中药杂志

Selaginella tamariscina is a typical resuscitation medicinal plant with extreme drought tolerance. Trehalose plays an important role in the resurrection process, and the trehalose-6-phosphate synthase(TPS) is the key enzyme to synthesize trehalose in plants. In this study, the sequence of TPS was obtained by splicing from the transcriptome data of S. tamariscina. After the synthesis of cDNA based on the template of total RNA, the sequence was cloned by RT-PCR for verification and then analyzed by bioinformatics methods. The results indicated that the full-length coding sequence of StTPS was 2 799 bp (GenBank accession no. MH155231), and the encoded protein contained 932 amino acids. StTPS could be located in the chloroplastid according to subcellular localization prediction. There were two conserved domains belonging to glycogen phosphorylase glycosyltransferase (GPGTF) family but no signal peptide or transmembrane domain in StTPS. The expression of StTPS was determined by qRT-PCR and the variation of trehalose content was measured by HPLC-ELSD during the resurrection process of S. tamariscina. Meanwhile, the correlation between them was analyzed. The results showed that both the expression level of StTPS and the trehalose content increased associated with the extension of dehydration time, and declined associated with the extension of rehydration time which proved a significant positive correlation between the StTPS expression level and the trehalose content. The results suggested that the StTPS probably plays a central role in recovery process in S. tamariscina.

Prokaryotic expression, functional identification of squalene synthase in Alisma orientale and its immunoassay study / 中国中药杂志

Squalene synthase of Alisma orientale catalyzes farnesyl diphosphate (FPP) to form squalene, which is the key regulatory enzyme of the carbon source flow to protostane triterpenes biosynthesis. For further research on the function and expression of AoSS gene, the open reading frame (ORF) of squalene synthase gene (accession no. JX866770) from A. orientale was subcloned into a prokaryotic expression vector pCzn1 and induced the expression of AoSS gene in Escherichia coli BL21(Roseta). The fusion protein was mainly in the form of inclusion bodies and purified to obtain high purity protein. By verifying its functionality through vitro enzymatic reaction, the results showed that the catalytic protein had the catalytic activity of FPP into squalene. In order to research the expression of AoSS in A. orientale, the purified protein was used to immunized rabbits to prepare polyclonal antibody which was then purified, the titer of the antibody was greater than 1∶51 200 by ELISA detection, and displayed good specificity by Western blotting. The prepared antibody was used for immunoassay of AoSS in different organs of A. orientale, and the results showed that the AoSS expression level was the highest in tubers, followed by leaves, and lowest in root. Successful construction of prokaryotic expression vector, validation of gene functions and establishment of rapid immunoassay lay the foundation for further researches on the function and regulation of AoSS gene, and also provide scientific basis on the application of the protostane triterpenes of A. orientale in the field of synthetic biology.