ABSTRACT
Thought-out utilization of entire lignocellulose is of great importance to achieving sustainable and cost-effective biorefineries. However, there is a trade-off between efficient carbohydrate utilization and lignin-to-chemical conversion yield. Here, we fractionate corn stover into a carbohydrate fraction with high enzymatic digestibility and reactive lignin with satisfactory catalytic depolymerization activity using a mild high-solid process with aqueous diethylamine (DEA). During the fractionation, in situ amination of lignin achieves extensive delignification, effective lignin stabilization, and dramatically reduced nonproductive adsorption of cellulase on the substrate. Furthermore, by designing a tandem fractionation-hydrogenolysis strategy, the dissolved lignin is depolymerized and aminated simultaneously to co-produce monophenolics and pyridine bases. The process represents the viable scheme of transforming real lignin into pyridine bases in high yield, resulting from the reactions between cleaved lignin side chains and amines. This work opens a promising approach to the efficient valorization of lignocellulose.
ABSTRACT
Background: The global coronavirus disease 2019 (COVID-19) pandemic has caused immeasurable losses to society. An important part of disease prevention and control is to diagnose infected patients as soon as possible, and nucleic acid detection plays an important role in diagnosing diseases such as COVID-19. Reverse transcription-polymerase chain reaction (RT-PCR) is a common method for the diagnosis of COVID-19 infection, but the false negative rate of covid nucleic acid is currently very high. Methods: In this paper, HEK293T cells and lentivirus were used to verify the effect of virus preservation solution, fluorescence method was used to verify the inactivation effect of virus preservation solution, real-time fluorescence PCR experiment was used to verify that the genetic material in virus particles was not destroyed, and protein gel electrophoresis was used to verify the integrity of virus particles in the preservation solution. Results: In this study, we developed a new virus preservation solution using homogeneous reaction technology that can immediately inactivate the virus within 5 minutes at room temperature and maintain the stability of viral nucleic acid for at least 7 days. Importantly, we found that while our solution differed from existing commercial preservatives that contain guanidinium, analyzing the cycle threshold (Ct) showed that it still maintained virion integrity. Conclusions: These advantages could reduce false negatives and the risk of laboratory exposure to infection. In addition, our solution achieved room temperature preservation, which could aid in the transportation of samples. Therefore, this new sample preservation solution could provide significant benefits to the clinical detection of viruses such as COVID-19.
ABSTRACT
BACKGROUND: Breast cancer is one of the most prevalent gynecologic malignancies worldwide. Despite the high sensitivity in response to chemotherapy, drug resistance occurred frequently in clinical treatment. Cryptotanshinone (CTS) is a herbal medicine and has been identified as an anti-inflammatory and anti-oxidative drug. METHODS: In vitro assays, including the cell proliferation assay, colony formation assay, Western blot analysis, transwell migration/invasion assays, and cell scratch assay were used to explore the biological activities and working mechanism of CTS. Breast cancer cells were also transfected with PKM2 expressing vectors to define the molecular mechanisms involved in CTS-mediated anti-tumor activity. RESULTS: We found that CTS shows anti-proliferative effects and decreases the clonogenic ability of breast cancer cells. We also found that CTS inhibited the migration and invasion activity of MCF-7 and MDA-MB-231 cells by different analyzed methods. CTS also downregulated the levels of glycolysis-related proteins, such as PKM2, LDHA, and HK2. In addition, overexpression of PKM2 recovered CTS-mediated suppression of cell proliferation, colony formation, and cell mobility of breast cancer cells. We also found PKM2 was significantly overexpressed in tumor tissues and invasive ductal breast carcinoma compared to normal tissues and patients with high PKM2 expression had worse overall survival and metastasis-free survival outcomes. CONCLUSION: CTS inhibited the proliferation, migration, and invasion of breast cancer cells. The involved mechanism may refer to the downregulation of the PKM2/ß-catenin axis.
