CRISPR-Cas12a Coupled with DNA Nanosheet-Amplified Fluorescence Anisotropy for Sensitive Detection of Biomolecules.

DNA nanosheets (DNSs) have been utilized effectively as a fluorescence anisotropy (FA) amplifier for biosensing. But, their sensitivity needs to be further improved. Herein, CRISPR-Cas12a with strong trans-cleavage activity was utilized to enhance the FA amplification ability of DNSs for the sensitive detection of miRNA-155 (miR-155) as a proof-of-principle target. In this method, the hybrid of the recognition probe of miR-155 (T1) and a blocker sequence (T2) was immobilized on the surface of magnetic beads (MBs). In the presence of miR-155, T2 was released by a strand displacement reaction, which activated the trans-cleavage activity of CRISPR-Cas12a. The single-stranded DNA (ssDNA) probe modified with a carboxytetramethylrhodamine (TAMRA) fluorophore was cleaved in large quantities and could not bind to the handle chain on DNSs, inducing a low FA value. In contrast, in the absence of miR-155, T2 could not be released and the trans-cleavage activity of CRISPR-Cas12a could not be activated. The TAMRA-modified ssDNA probe remained intact and was complementary to the handle chain on the DNSs, and a high FA value was obtained. Thus, miR-155 was detected through the obviously decreased FA value with a low limit of detection (LOD) of 40 pM. Impressively, the sensitivity of this method was greatly improved about 322 times by CRISPR-Cas12a, confirming the amazing signal amplification ability of CRISPR-Cas12a. At the same time, the SARS-CoV-2 nucleocapsid protein was detected by the strategy successfully, indicating that this method was general. Moreover, this method has been applied in the analysis of miR-155 in human serum and the lysates of cells, which provides a new avenue for the sensitive determination of biomarkers in biochemical research and disease diagnosis.

[Qualitative and quantitative study of constituents in Lysionoti Herba based on UHPLC-Q-Exactive Orbitrap HRMS and HPLC-UV].

Ultra-high performance liquid chromatography-quadrupole-Exactive Orbitrap high resolution mass spectrometry(UHPLC-Q-Exactive Orbitrap HRMS) was employed to systematically analyze the chemical constituents in Lysionoti Herba, and high perfor-mance liquid chromatography-ultraviolet(HPLC-UV) to determine the content of main compounds. A Synergi~(TM) Hydro-RP 100 Å colu-mn(2 mm×100 mm, 2.5 µm) was used for gradient elution with acetonitrile-0.1% aqueous formic acid as the mobile phase at a flow rate of 0.2 mL·min~(-1) and a column temperature of 40 ℃. MS and MS/MS were conducted with electrospray ionization(ESI) in both positive and negative modes. The chemical components in Lysionoti Herba were identified by comparison with the retention time and mass spectra of reference compounds and the relevant mass spectral data reported in MS databases and relevant literature. Furthermore, the content of five constituents(neochlorogenic acid, chlorogenic acid, forsythoside B, acteoside, and nevadensin) in different Lysiono-ti Herba samples was simultaneously determined by HPLC-UV at the wavelength of 330 nm. A total of 84 compounds were identified in Lysionoti Herba, including 27 flavonoids, 20 phenylethanoid glycosides, 5 amino acids, 18 organic acids, 1 alkaloid, 6 nucleosides, and 7 others. The content of neochlorogenic acid, chlorogenic acid, forsythoside B, acteoside, and nevadensin showed good linear relationship(r>0.999) with the peak area within certain concentration ranges, which were 3.22-102.90, 12.84-410.82, 31.63-1 012.01, 25.00-800.11, and 4.08-130.51 µg·mL~(-1), respectively. The instrument precision, method repeatability, and solution stability all met requirement, and the average recovery rate was 97.31%-100.2%, with RSD ranging from 0.95% to 2.4%. The content of the five components varied among different Lysionoti Herba samples collected from different regions of Guizhou, and the average content of forsythoside B was the highest. The established qualitative method can rapidly and efficiently identify the chemical components of Lysionoti Herba, and the developed HPLC-UV method can simultaneously determine the content of five components in a simple, ra-pid, and accurate manner, providing a scientific basis for the quality evaluation of Lysionoti Herba.

Early-life gut microbial colonization shapes Th1/Th2 balance in asthma model in BALB/c mice.

BACKGROUND: We aimed to investigate the effect of early-life diverse microbial exposures on gut microbial colonization in an OVA-induced asthma model in BALB/c mice. METHODS: BALB/c mice were divided into 4 groups: A, offsprings were kept in a SPF environment during fetal, lactation, and childhood periods; B, offsprings were kept in the SPF environment during fetal and lactation periods, and kept in the general environment during childhood; C, offsprings were kept in the SPF environment only during fetal period, and then kept in the general environment; and D, offsprings were kept in the general environment during whole periods. The diversity of intestinal flora was analyzed using denaturing gradient gel electrophoresis. Mice were sensitized with OVA to establish an animal model of asthma. Then asthma-related inflammatory cytokines and histological analysis were performed. RESULTS: The diversity of intestinal microflora in group D was significantly higher than groups A, B and C at three days and three weeks after birth, and the diversity of intestinal microflora in groups C and D were significantly higher than groups A and B at five weeks after birth. The pathologic scores of OVA-induced asthmatic mice in group D were significantly lower than group A, and serum IFN-γ levels and the IFN-γ/IL-4 ratio in group D were significantly higher than group A. CONCLUSIONS: Exposure to diverse microbial environments in early life affects gut microbial colonization in BALB/c mice. The diversity of the intestinal flora in early life may prevent airway inflammation in asthma via regulating the Th1/Th2 balance.

[Influence of Ammonium Sulfate and Ammonium Nitrate on the Properties of Ambient PM2.5 in Zhenjiang].

Recently, the contribution of inorganic salts (nitrates in particular) to the mass concentration of particulate matter with an aerodynamic diameter of less than 2.5 µm (PM2.5) has been increasing across China. However, it is urgent to understand how the increased inorganic salts affect the crucial properties of PM2.5. Here, we conducted continuous field observations at Zhenjiang Ecology and Environment Protection Bureau from January 1 to December 31, 2021. The mass concentrations of ammonium sulfate[(NH4)2SO4] and ammonium nitrate (NH4NO3) were calculated using different methods. The contributions of (NH4)2SO4 and NH4NO3 to the extinction coefficient, hygroscopic growth, and acidity of PM2.5 were discussed in detail. Our results demonstrated that the mean mass concentrations of (NH4)2SO4 and NH4NO3 during the study period were (6.5±4.5) and (15.0±13.3) µg·m-3, which contributed (20.5±18.2)% and (34.5±18.4)% to the mass concentration of PM2.5, respectively. The total extinction coefficient of PM2.5 was (224.5±194.2) Mm-1, in which NH4NO3 was the largest contributor[(40.1±20.9)%] followed by (NH4)2SO4[(19.1±10.8)%]. (NH4)2SO4 and NH4NO3 were also the dominant contributors to the hygroscopic growth of PM2.5. In particular, NH4NO3contributed from (53.8±13.4)% to (61.6±14.6)% to the aerosol water content of PM2.5 under pollution conditions. Thus, NH4NO3 was a key air pollutant to be targeted for further improving the visibility and air quality in Zhenjiang in the future. However, the reduction in the precursors of NH4NO3 would lead to an increase in aerosol acidity, particularly in the spring and winter seasons. Our results help us understand the evolution of air quality and the related impacts and also provide important information on air quality improvement in Zhenjiang in the future.

miR-29a-3p promotes the regulatory role of eicosapentaenoic acid in the NLRP3 inflammasome and autophagy in microglial cells.

Eicosapentaenoic acid (EPA) has been reported to play an anti-inflammatory and antioxidative stress role in a series of human diseases, including major depressive disorder. However, its exact mechanism is still largely unknown. Mouse BV-2 cells were treated with lipopolysaccharide (LPS) to induce an in vitro inflammatory cell model of depression. Cytotoxic effects were assessed with MTT and lactate dehydrigebase release assays. Cytokine mediators were elevated by western blot and enzyme-linked immunosorbent assays. Autophagy-relators were determined by immunofluorescence and western blot analyses. Interaction relationships among molecules were evaluated utilizing chromatin immunoprecipitation and dual luciferase assays. Methylated miR-29a-3p was detected via methylation-specific polymerase chain reaction. EPA treatment at 60 µM had no cytotoxic effects on BV2 cells and significantly inhibited the LPS-induced inflammatory response and NLRP3 inflammasome but activated autophagy, while all these effects were reversed by the autophagy inhibitor 3-MA. Importantly, miR-29a-3p exhibited a role similar to that of EPA in LPS-treated BV2 cells. Mechanistically, EPA treatment elevated miR-29a-3p by repressing its promoter methylation. MAPK8 was a direct target of miR-29a-3p. Inhibition of miR-29a-3p greatly diminished the regulatory roles mediated by EPA in LPS-treated BV2 cells, while these roles were further impeded after MAPK8 silencing. To conclude, our data demonstrated that EPA treatment alleviated LPS-induced NLRP3 inflammasomes by activating autophagy via regulation of miR-29a-3p/MAPK8 signaling, which further elucidates the potential antidepressant mechanism of EPA.

Bis[µ(2)-bis-(diphenyl-phosphan-yl)methane-κP:P']bis-(µ(4)-diphenyl-phosphinato-κO:O:O':O')bis-[µ(2)-trifluoro-methane-sulfonato-(0.546/0.454)]-κO:O';κO:O-tetra-silver(I) acetonitrile disolvate.

In the centrosymmetric tetra-nuclear title compound, [Ag(4)(C(12)H(10)O(2)P)(2)(CF(3)O(3)S)(2)(C(25)H(22)P(2))(2)]·2CH(3)CN, the Ag(I) atom is coordinated by one P atom from a bis-(diphenyl-phosphan-yl)methane (dppm) ligand, two O atoms from two diphenyl-phosphinate (dpp) ligands and one O atom from a trifluoro-methane-sulfonate (OTf) anion in a highly distorted tetra-hedral geometry. Four Ag(I) atoms are bridged by two dppm ligands, two dpp ligands and two OTf anions, forming a tetra-nuclear complex. An weak intra-molecular Ag⋯Ag [3.2692 (14) Å] inter-action is observed. The OTf anion and one of the phenyl groups in the dppm ligand are disordered over two sets of positions in a 0.546 (4):0.454 (4) ratio. The 0.546-occupied OTf is bonded to two Ag atoms in a µ-(κ(2)O:O') mode, while the 0.454-occupied OTf is bonded in a µ-(κ(2)O:O) mode. The methyl group of the acetonitrile solvent mol-ecule is also disordered over two positions with equal occupancy factors.

A novel drug delivery system of mixed micelles based on poly(ethylene glycol)-poly(lactide) and poly(ethylene glycol)-poly(ɛ-caprolactone) for gambogenic acid.

In this study, a novel mixed polymeric micelles formed from biocompatible polymers, poly(ethylene glycol)-poly(lactide) (mPEG-PLA) and poly(ethylene glycol)-poly(ɛ-caprolactone) (mPEG-PCL), used as a novel nanocarrier to encapsulate gambogenic acid (GNA). GNA-loaded mixed polymeric micelles (GNA-MMs) was prepared by cosolvent evaporation method. The mean average size of GNA-MMs was (83.23 ± 1.06) nm (n = 3) and entrapment efficiency (EE%) of GNA-MMs was (90.18 ± 2.59) % (n = 3) as well as (12.36 ± 0.64) % (n = 3) for drug loading (DL%). Transmission electron microscopy revealed that the GNA-MMs were spherical with "core-shell" structures. Compared with free GNA solution, in vitro release of GNA from GNA-MMs showed a two-phase sustained release profile: an initial relatively fast phase and followed by a slower release phase. Pharmacokinetic results also indicated that the GNA-MMs have longer systemic circulation time and slower plasma elimination rate than free GNA solution. Moreover, the in vitro cytotoxicity assay showed that the IC50 values on HepG2 cells for GNA-MMs and free GNA were (5.67 ± 0.02) µM and (9.02 ± 0.03) µM, respectively. In addition, GNA-MMs significantly increased the HepG2 cellular apoptosis in a concentration-dependent manner. In conclusion, the results showed that mPEG-PLA/mPEG-PCL mixed micelles may serve as an ideal drug delivery system for GNA to prolong drug circulation time in body, enhance bioavailability and retained its potent antitumor effect.