Role of Lipid Composition in the Antimicrobial Peptide Double Cooperative Effect.

The antimicrobial peptide double cooperative effect, where the mixture of two major antimicrobial peptides LL-37 and HNP1 kills bacteria more efficiently while minimizing the host damage by suppressing mammalian cell membrane lysis, has garnered attention due to its potential applications toward efficient and safe antibiotics. However, its mechanism is completely unknown. In this work, we report that the double cooperative effect can be partially recapitulated in synthetic lipid systems just by varying the lipid composition between eukaryotic and Escherichia coli membranes. Although real cell membranes are so much more complex than just lipids, including, e.g., membrane proteins and polysaccharides, our data implicates that one of the main driving forces of the double cooperative effect is a simple lipid-peptide interaction.

Colorimetric response in polydiacetylene at the single domain level using hyperspectral microscopy.

The structural variance of polydiacetylene (PDA) at the nanoscale level, even under the same fabrication conditions, is one of the origins of its poor reproducibility in chemo/biosensing. In this work, we present a spatial map of such structural distributions within a single crystal by taking advantage of the recent development of hyperspectral microscopy at visible wavelengths. Hyperspectral microscopy provides the distribution of absorption spectra at the spatial resolution of standard optical microscopy. By tracking the blue-to-red transition via this technique, we found that heat or pH stimulation leaves a unique pattern in the transition pathways.

Synthesis of sheet-like polypyrrole nanowires for the microextraction of trace residues of pyrethroid pesticides in human plasma and molecular dynamics-aided study of adsorption mechanism.

The synthesized sheet-like polypyrrole (ppy) nanowires were used as solid phase extraction materials, followed by gas chromatography-mass spectrometry (GC-MS) for the detection of traces residues of pyrethroid pesticides in human plasma. A multiresidue method was developed and verified for the determination of trace pyrethroid residues (transfluthrin, allethrin, resmethrin, fenpropathrin, etofenprox, fenvalerate) in human plasma. In this study, using the cationic surfactant cetyltrimethylammonium bromide (CTAB) as a soft template, ppy nanowires with regular morphology were prepared by oxidative polymerization. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction analysis (XRD), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA) and other techniques were employed for characterization. Molecular dynamics analyses were used to simulate the adsorption mechanism of each pyrethroid and ppy nanowires. Based on density analysis, molecular recognition analysis, and binding energy, the van der Waals force was considered as an important driving force for the adsorption of pyrethroids and ppy nanowires. The limits of detection (LOD) of six pyrethroids were 0.008-0051 ng mL-1, and the limits of quantification (LOQ) were 0.028-0.162 ng mL-1. The relative standard deviations of ppy nanowires were 2.12-5.09%, and the recoveries of six pyrethroids ranged from 76.9 to 110.4%. The enrichment factors were within the range of 47.09-51.30. The experimental results showed that the method could be an efficient detection method for trace residue analysis of pyrethroid pesticides in complex biological samples. It would be advantageous for clinical monitoring and toxicological studies of pyrethroids.

One-step ionic liquid-based ultrasound-assisted dispersive liquid-liquid microextraction coupled with high-performance liquid chromatography for the determination of pyrethroids in traditional Chinese medicine oral liquid preparations.

In this study, a simple one-step ionic liquid-based ultrasound-assisted dispersive liquid-liquid microextraction technique was coupled with high-performance liquid chromatography for the analysis of four pyrethroids in three kinds of traditional Chinese medicine oral liquid preparations: simotang oral liquid, kangbingdu oral liquid, and huaji oral liquid. The extraction parameters were examined to improve extraction efficiency. The optimum extraction conditions were 50 µL of 1-octyl-3-methylimidazolium hexafluorophosphate utilized as the extraction solvent and 800 µL of acetonitrile applied as the dispersive solvent. The extraction was assisted by ultrasonication for 8 min. The limits of detection for the four pyrethroids were within 0.007-0.024 mg L-1, and the limits of quantitation ranged between 0.023 and 0.080 mg L-1. The accuracy of the pyrethroid determination ranged from 80.1 to 106.4%. It was indicated that the proposed ionic liquid-based ultrasound-assisted dispersive liquid-liquid microextraction method had an easy operation and was accurate and environmentally friendly. This approach has potential for the analysis of pyrethroids in traditional Chinese medicine oral liquid preparations.

A Modified QuEChERS Method for Determination of Pyrethroid Residues in Traditional Chinese Medicine Oral Liquids by High-Performance Liquid Chromatography.

Pyrethroid residues in traditional Chinese medicines have been a serious threat to the health and treatment of patients. However, because of the matrix complexity of traditional Chinese medicine, the detection of pyrethroid residues remains a challenge. Therefore, we developed a QuEChERS method coupled with high-performance liquid chromatography and ultraviolet detection (HPLC-UV) for the determination of pyrethroid pesticides in three kinds of traditional Chinese medicine oral liquid preparations, and we investigated and optimized the extraction conditions. The matrix effect was estimated in the organic solvent and the actual samples by comparing the slopes of calibration curves, and the results showed that the matrix effect is not significant when using the modified QuEChERS method. The pyrethroid pesticides could be completely separated in 30 min. The linear correlation coefficients were more than 0.999, and the recoveries of all the pyrethroid pesticides ranged from 87.2% to 104.8%. The intra-day precisions (n = 5) were 2.44-4.62%, and the inter-day precisions (n = 5) were 1.06-3.02%. Moreover, the limits of detection were in the range of 0.007-0.018 ng mL-1, while the limits of quantitation were in the range of 0.022-0.057 ng mL-1. This simple, low-cost, and highly sensitive analytical method can be a potential tool for the analysis of pyrethroid residues in traditional Chinese medicine oral liquid preparations.

LncRNA DBH-AS1 facilitates the tumorigenesis of hepatocellular carcinoma by targeting miR-138 via FAK/Src/ERK pathway.

BACKGROUND: It has been reported that dysregulated lncRNAs are associated with the pathogenesis of human tumors including hepatocellular carcinoma (HCC). LncRNA DBH-AS1 was reported to be an oncogene in HCC. However, the molecular mechanisms of DBH-AS1 in HCC progression are largely undefined. METHODS: The expressions of DBH-AS1 and miR-138 in HCC tissues and cells were examined by qRT-PCR. The effects of DBH-AS1 and miR-138 on cell viability, colony formation, apoptosis, and FAK/Src/ERK signaling pathway were determined by CCK-8, colony formation, flow cytometry, and western blot analyses, respectively. Luciferase reporter assay and RNA immunoprecipitation (RIP) assay were used to explore the interaction between miR-138 and DBH-AS1. Tumor xenograft assay was performed to confirm the function and mechanism of DBH-AS1 in the progression of HCC in vivo. RESULTS: DBH-AS1 expression was upregulated and miR-138 expression was downregulated in HCC tissues and cells. DBH-AS1 silencing and miR-138 overexpression reduced cell viability, inhibited colony formation, and induced apoptosis. Moreover, DBH-AS1 acted as a molecular sponge of miR-138 to downregulate miR-138 expression. Also, DBH-AS1 overexpression attenuated miR-138-mediated anti-proliferation and pro-apoptosis effects. Additionally, miR-138 overexpression gave rise to a blockage on FAK/Src/ERK pathway, while this effect was undermined by increased DBH-AS1. Furthermore, DBH-AS1 promoted tumor growth and induced the activation of FAK/Src/ERK pathway by targeting miR-138 in vivo. CONCLUSION: DBH-AS1 facilitated the development of HCC via miR-138/FAK/Src/ERK pathway, establishing the molecular basis of DBH-AS1 in clinical application for HCC.