Screening of Endophytic Fungi in Locoweed Induced by Heavy-Ion Irradiation and Study on Swainsonine Biosynthesis Pathway.

Swainsonine (SW) is a substance with both animal neurotoxicity and natural anticancer activity produced by the metabolism of endophytic fungus Alternaria section Undifilum oxytropis of locoweed. This paper produced SW by fermentation of the endophytic fungus A. oxytropis of locoweed and obtained the optimal ultrasonic-assisted extraction process of SW by the response surface methodology. Meanwhile, four mutant strains with significant and stable SW-producing properties were screened out after the mutagenesis of A. oxytropis by heavy-ion irradiation. Of these, three were high-yielding stains and one was a low-yielding strain. In addition, through the analysis of metabolomics studies, it was speculated that the different SW production performance of the mutant might be related to the biosynthesis and utilization of L-lysine, L-2-aminoadipate-6-semialdehyde, etc. These results laid the foundation for the expansion of SW production, artificial construction of low-toxic locoweed and clarification of the SW biosynthesis pathway in A. oxytropis.

Antioxidant Activity and the Potential Mechanism of the Fruit From Ailanthus altissima Swingle.

The fruits of Ailanthus altissima Swingle (AS) possess a variety of pharmacological activities. Its antioxidant activity and the potential mode of action have not yet been investigated. In in vitro studies, AS revealed the strong reducing power and DPPH scavenging effect, but hydroxyl radical scavenging activity and ferrous ions-chelating ability were not strong. Meanwhile, the oxidative stress RAW264.7 cell injury model was established, the low and medium-doses of AS showed significant protective effects on the viability of H2O2-treated cells by CCK-8 method. Besides, three doses of AS all increased the activities of SOD, CAT, and GSH-Px and decreased the MDA level compared with the H2O2 group, suggesting it significantly relieved oxidative stress of cells. The active ingredients and related targets of AS were collected by HERB and Swiss Target Prediction database, the common targets of drugs and diseases database were conducted by GeneCards database platform and the Venny platform. We screened the core targets of AS like threonine kinase1 (AKT1), mitogen-activated protein kinase 1 (MAPK1), sirtuin-1 (SIRT1), mechanistic target of rapamycin kinase (MTOR) by STRING database, and the key pathways involved PI3K-AKT and FoxO signaling pathway by KEGG pathway enrichment analysis. Besides, qRT-PCR revealed AS preconditioning significantly up-regulated the expression level of AKT1, SIRT1, MAPK1, and MTOR in model cells, and the effect was related to the regulation of FoxO and PI3K/AKT signaling pathway. In summary, AS showed significant antioxidant activity and its potential mechanism was regulating FoxO and PI3K/AKT signaling pathway.

Integration of metabolomics and transcriptomics indicates changes in MRSA exposed to terpinen-4-ol.

BACKGROUND: This study investigated the effects of terpinen-4-ol on methicillin-resistant Staphylococcus aureus (MRSA) and its biofilm, and the possible mechanisms governing this effect. RESULTS: We observed that terpinen-4-ol has good antibacterial activity and inhibits the formation of MRSA biofilm. The MIC and MBC values for terpinen-4-ol against S. aureus were 0.08% ~ 0.32%. And terpinen-4-ol at 0.32% could kill all bacteria and clear all biofilms. Untargeted metabolomic and transcriptomic analyses showed that terpinen-4-ol strongly inhibited DNA and RNA biosynthesis in MRSA at 2 h after treatment by affecting genes and metabolites related to purine and pyrimidine metabolic pathways. Some differential genes which play important roles in DNA synthesis and the production of eDNA from biofilm exposed to terpinen-4-ol was also significantly decreased compared with that of the control. CONCLUSIONS: Terpinen-4-ol has good antibacterial activity and significantly inhibits the formation of MRSA biofilm by inhibiting purine and pyrimidine metabolism.

Antioxidant Effects and Potential Molecular Mechanism of Action of Limonium aureum Extract Based on Systematic Network Pharmacology.

Oxidative stress is the redox imbalance state of organisms that involves in a variety of biological processes of diseases. Limonium aureum (L.) Hill. is an excellent wild plant resource in northern China, which has potential application value for treating oxidative stress. However, there are few studies that focused on the antioxidant effect and related mechanism of L. aureum. Thus, the present study combining systematic network pharmacology and molecular biology aimed to investigate the antioxidant effects of L. aureum and explore its underlying anti-oxidation mechanisms. First, the antioxidant activity of L. aureum extracts was confirmed by in vitro and intracellular antioxidant assays. Then, a total of 11 bioactive compounds, 102 predicted targets, and 70 antioxidant-related targets were obtained from open source databases. For elucidating the molecular mechanisms of L. aureum, the PPI network and integrated visualization network based on bioinformatics assays were constructed to preliminarily understand the active compounds and related targets. The subsequent enrichment analysis results showed that L. aureum mainly affect the biological processes involving oxidation-reduction process, response to drug, etc., and the interference with these biological processes might be due to the simultaneous influence on multiple signaling pathways, including the HIF-1 and ERBB signaling pathways. Moreover, the mRNA levels of predicted hub genes were measured by qRT-PCR to verify the regulatory effect of L. aureum on them. Collectively, this finding lays a foundation for further elucidating the anti-oxidative damage mechanism of L. aureum and promotes the development of therapeutic drugs for oxidative stress.

In vitro biocompatibility of a platinum-electrode embedded photosensitive polyimide (Durimide) retinal prosthesis.

PURPOSE: The photosensitive polyimide film, Durimide, is a common component of retinal prostheses; however, retinal cell response to Durimide has not been effectively studied This work assessed the in vitro biocompatibility of a retinal prosthesis containing platinum-electrode embedded Durimide film. MATERIALS AND METHODS: Biocompatibility evaluation assessed cytotoxicity, attachment, and proliferation of two cell lines: a human retinal pigmented epithelium cell line (CRL) and a rhesus monkey choroid- retinal endothelial cell line (RF/6A). Cells were cultured with the platinum-electrode embedded Durimide film, with tissue-culture treated polystyrene plates (TCPS) used as a control substrate for cell growth. The effect of a Durimide-exposed medium on cell apoptosis and life cycle was assessed using flow cytometry (FCM). RESULTS: The indirect cytotoxicity evaluation revealed no toxic effect of the prosthesis on cells. The attachment and proliferation of CRL and RF/6A cells cultured with the Durimide prostheses showed no significant differences to the control. The FCM experiments demonstrated a liquid medium exposed to the prosthesis had no effects on apoptosis or cell life cycle in comparison with the control (p > 0.05). CONCLUSIONS: The results demonstrate that Durimide has good biocompatibility with retinal cell lines CRL and RF/6A. In conclusion, while further in vitro and in vivo studies are required to clarify long-term effects, Durimide is indicated as a promising material with suitable biocompatibility for retinal implants.