Transcriptome analysis revealed enrichment pathways and regulation of gene expression associated with somatic embryogenesis in Camellia sinensis.

The high frequency, stable somatic embryo system of tea has still not been established due to the limitations of its own characteristics and therefore severely restricts the genetic research and breeding process of tea plants. In this study, the transcriptome was used to illustrate the mechanisms of gene expression regulation in the somatic embryogenesis of tea plants. The number of DEGs for the (IS intermediate stage)_PS (preliminary stage), ES (embryoid stage)_IS and ES_PS stages were 109, 2848 and 1697, respectively. The enrichment analysis showed that carbohydrate metabolic processes were considerably enriched at the ES_IS stage and performed a key role in somatic embryogenesis, while enhanced light capture in photosystem I could provide the material basis for carbohydrates. The pathway analysis showed that the enriched pathways in IS_PS process were far less than those in ES_IS or ES_PS, and the photosynthesis and photosynthetic antenna protein pathway of DEGs in ES_IS or ES_PS stage were notably enriched and up-regulated. The key photosynthesis and photosynthesis antenna protein pathways and the Lhcb1 gene were discovered in tea plants somatic embryogenesis. These results were of great significance to clarify the mechanism of somatic embryogenesis and the breeding research of tea plants.

Four new cytotoxic xanthones from Garcinia nujiangensis.

Bioassay-guided fractionation of the acetone extract of the twigs of Garcinia nujiangensis resulted in the isolation of four new prenylated xanthones, nujiangexanthones C-F (1-4), and ten known related analogues. The structures of compounds 1-4 were elucidated by interpretation of their spectroscopic data. The compounds isolated were evaluated for their cytotoxic effects against three cancer cell lines, the test substances demonstrated selectivity toward the cancer cells.

Degradation of pentachlorophenol by potato polyphenol oxidase.

In this study, polyphenol oxidase (PPO) was extracted from commercial potatoes. Degradation of pentachlorophenol by potato PPO was investigated. The experimental results show that potato PPO is more active in weak acid than in basic condition and that the optimum pH for the reaction is 5.0. The degradation of pentachlorophenol by potato PPO reaches a maximum at 298 K. After reaction for 1 h, the removal of both pentachlorophenol and total organic carbon is >70% with 6.0 units/mL potato PPO at pH 5.0 and 298 K. Pentachlorophenol can be degraded through dechlorination and ring-opening by potato PPO. The work demonstrates that pentachlorophenol can be effectively eliminated by crude potato PPO.

Double-antigen sandwich time-resolved immunofluorometric assay for the detection of anti-hepatitis C virus total antibodies with improved specificity and sensitivity.

Current anti-hepatitis C virus (HCV) antibody screening immunoassays are routinely based on an indirect format. Although their use for anti-HCV antibody detection has achieved a very high specificity and sensitivity, false-positive results are still a problem especially among populations with a low prevalence of HCV infection. One strategy to obviate this problem is to adapt the assay from an indirect format to a double-antigen sandwich one to further improve its specificity. In this study, a double-antigen sandwich time-resolved immunofluorometric assay (DAS-TRIFMA) has been developed to detect total anti-HCV antibodies based on biotin-streptavidin interaction. For comparison, 1025 samples were analysed by the DAS-TRIFMA and three indirect anti-HCV antibody detection methods. For samples with discordant results, PCR-ELISA and Inno-LIA were employed as supplementary assays to analyse the presence of HCV antibodies. With regard to the 1025 clinical samples, the overall concordance between the DAS-TRIFMA and the three indirect methods was 99.41, 98.93 and 98.93 % for Ortho ELISA 3.0, WAT ELISA and I-TRIFMA, respectively. The specificity/sensitivity of the DAS-TRIFMA, Ortho HCV ELISA 3.0, WAT HCV ELISA and I-TRIFMA were 100/99.09, 99.34/98.18, 99.23/97.27 and 99.01 %/98.18 %, respectively. The DAS-TRIFMA was able to detect HCV antibodies at a concentration about 1/10 of that detectable by indirect methods. From the obtained results and their comparison, it is concluded that the DAS-TRIFMA is a more specific and reliable method for screening anti-HCV antibodies, and weakly positive S/Co values by the DAS-TRIFMA were more predictive of HCV infection than those by indirect methods.

Synergistic effect of triptolide combined with 5-fluorouracil on colon carcinoma.

AIM: To investigate the inhibitive effects of triptolide (TPL) combined with 5-fluorouracil (5-FU) on colon carcinoma HT-29 cells in vitro and in vivo and their side effects. METHODS: HT-29 cells were cultured with RPMI 1640 medium. The single or combined effects of TPL and 5-FU on HT-29 cells were examined by MTT assay, flow cytometry. The combined effects were evaluated by the median-effect principle. The model of tumour xenografts was established in nude mice. TPL 0.25 mg/kg/day and 5-FU 12 mg/kg/day, either in combination or on their own, were injected into mice and the inhibitive effects and side effects were observed. RESULTS: TPL and 5-FU either combined or alone inhibited significantly the proliferation of HT-29 cells and induced obvious apoptosis. Mean (SD) growth inhibition rate reached 94.92 (2.76)% and the apoptic rate at 48 h reached 41.71 (1.38)%. The combined effects were synergistic (CI<1) at lower concentrations. TPL or 5-FU alone inhibited significantly the growth of tumour xenografts and the inhibition rates were 78.53% and 84.16%; the drugs combined had more significant effect, the tumour inhibition rate reaching 96.78%. During the course of chemotherapy, no obvious side effect was observed. CONCLUSION: The combined effects of TPL and 5-FU on the growth of colon carcinoma in vitro and in vivo were superior to the effects when the agents were used individually. TPL combined with 5-FU had synergistic effects at lower concentrations and promoted apoptosis, but did not increase the side effects of chemotherapy.