Ionizable copolymer functionalized magnetic nanocomposite as an adsorbent for boosting the extraction selectivity of aristolochic acids.

Aristolochic acid nephropathy (AAN) has drawn increasing public attention. Organic anion transporters (OATs) are considered to be responsible for mediating nephrotoxicity of aristolochic acids (AAs), as AAs are typical OAT1 substrates that exhibit anionic properties and contain one hydrophobic domain. Inspired by the OAT1 three-dimensional structure or substrate/protein interactions involved in transport, we designed a magnetic polymeric hybrid, mimicking the effect of basic and aromatic residues of OAT1, for efficient enriching aristolochic acid I (AA I) and aristolochic acid II (AA II) in Traditional Chinese patent medicines (TCPM). N, N-dimethylaminopropyl acrylamide (DMAPAm) was used as a cationic monomer and copolymerized with divinylbenzene (DVB) onto the surface of monodisperse magnetic nanoparticles (denoted as MNs@SiO2T-DvbDam). The magnetic polymer hybrid demonstrated high selectivity and capacity for AAs, which was mainly attributed to (1) electrostatic interactions from the cationic or basic moiety of DMAPAm and (2) the hydrophobic and π-π stacking interactions from the aromatic ring of DVB. Additionally, the surface of the hybrid exhibited amphiphilic property according to the ionization of DMAPAm, thus improving the compatibility of the adsorbent with the aqueous sample matrix. This strategy was proven to be robust in the analysis of real drug samples, which was characterized by a good linearity, high recovery and satisfactory reusability. This work confirmed that the proposed tool could be a promising candidate for enhancing the extraction selectivity of AAs in Traditional Chinese medicines (TCM).

Induction of autophagy and endoplasmic reticulum autophagy caused by cadmium telluride quantum dots are protective mechanisms of yeast cell.

Quantum dots (QDs), with unique and tunable optical properties, have been widely used in many fields closely related to our daily lives, such as biomedical application and electronic products. Therefore, the potential toxicity of QDs on the human health should be understood. Autophagy plays an important role in cell survival and death. Endoplasmic reticulum autophagy (ER-phagy), a selective autophagy that degrades ER, responds to the accumulation of misfolded proteins and ER stress. Although many reports have revealed that autophagy can be disturbed by cadmium telluride (CdTe)-QDs and other nanomaterials, there are still lack more detailed researches to illustrate the function of autophagy in CdTe-QDs-treated cells, and the function of ER-phagy in CdTe-QDs-treated cells remains to be illustrated. On the basis of transcriptome analysis, we explored the effect of CdTe-QDs on Saccharomyces cerevisiae and first illustrated that both of autophagy and ER-phagy were protective mechanisms in CdTe-QDs-treated cells. It was found that CdTe-QDs inhibited the proliferation of yeast cells, disrupted homeostasis of cells, membrane integrity, and metabolism process. All of these can be reasons of the reduction of cell viability. The abolishment of autophagy and ER-phagy reduce the cell survival, indicating both of them are cell protective mechanisms against CdTe-QDs toxicity in yeast cells. Therefore, our data are significant for the application of CdTe-QDs and provide precious information for understanding of nanomaterials-related ER-phagy.

A universal array platform for ultrasensitive, high-throughput and microvolume detection of heavy metal, nucleic acid and bacteria based on photonic crystals combined with DNA nanomachine.

The development of a universal, sensitive, and rapid assay platform to achieve detections of heavy metal, nucleic acid and bacteria is of great significance but it also faces a thorny challenge. Herein, a novel and universal array platform was developed by combining photonic crystals (PCs) and DNA nanomachine. The developed array platform integrated the physical and biological signal amplification ability of PCs and DNA nanomachine, resulting in ultrasensitive detections of Hg2+, DNA, and Shigella sonnei with limits of detection (LODs) of 22.1 ppt, 31.6 fM, and 9 CFU/mL, respectively. More importantly, by utilizing a microplate reader as signal output device, the array achieved high-throughput scanning (96 samples/3 min) with only 2 µL loading sample, which is advantageous for the detection of infectious dangerous targets. In addition, the PCs array could be obtained easily and rapidly based on self-assembly of colloidal nanospheres, and the DNA nanomachine was operated with enzyme-free and time-saving features. Benefiting from these merits, the proposed PCs array offered a powerful universal platform for large-scale detection of various analytes in the fields of pollution monitoring, epidemic control, and public health.

The M6A methyltransferase METTL3 regulates proliferation in esophageal squamous cell carcinoma.

Esophageal squamous cell carcinoma (ESCC) is one of the most lethal human cancers with a lower 5-year survival rate. N6-methyladenosine (m6A) methylation, an important epigenetic modification, has been reported to associate with physiological and pathological processes of cancers. However, its role in ESCC remains unclear. In this work, we found that the m6A levels were elevated in ESCC cancer tissues and ESCC cells. The PPI network demonstrated that METTL3, METTL14, WTAP, RBM15, and KIAA1429 were all significantly associated with each other. Moreover, we found a significant upregulation of METTL3 mRNA and protein amounts in ESCC tissues. The METTL3 mRNA expression level of tissues had associations with ESCC differentiation extent and sex (p < 0.05). The METTL3 mRNA expression level of tissues, sensitivity for diagnosing ESCC was 75.00%, specificity was 72.06% and area under the ROC curve was 0.8030. Depletion of METTL3 markedly diminished m6A levels in human ESCC cell lines and METTL3 overexpression restored the reduction in m6A levels. These results suggested that METTL3 is the primary enzyme that modulates m6A methylation and a critical regulatory factor in ESCC. Additionally, METTL3 knockdown significantly suppressed the ESCC cell proliferation, while METTL3 overexpression markedly promoted ESCC cell proliferation both in cell and animal models. These results demonstrated that METTL3 promotes ESCC development. Furthermore, METTL3 may modulate the cell cycle of ESCC cells through a p21-dependent pattern. METTL3-guided m6A modification may contribute to the progression of ESCC via the p21-axis. Our study is the first investigation to report that METTL3-mediated m6A methylation plays a crucial role in ESCC oncogenesis and highlights that METTL3 might be a potential biomarker and therapeutic target for ESCC patients.

An enzyme-mediated universal fluorescent biosensor template for pathogen detection based on a three-dimensional DNA walker and catalyzed hairpin assembly.

An enzyme-mediated universal fluorescent biosensor template for rapid detection of pathogens was developed based on the strategy of a three-dimensional (3D) DNA walker and catalyzed hairpin assembly (CHA) reaction. In the bacterial recognition step, a strand displacement reaction between bacteria and the double-stranded complex caused the release of the walker strand. The walker strand triggered the DNA walker to produce an enzyme fragment, and the DNA walker used gold nanoparticles (AuNPs) as the track to provide an excellent DNA ligand anchoring area. In the CHA step, the enzyme fragment induced the CHA cycle to yield fluorescence signals, which greatly enhanced the conversion ratio of trigger DNA and the sensitivity of the fluorescent biosensor. The effect of the distance and density of the DNA ligand was studied by adjusting the length of poly-adenine (PolyA), and was further explored by its reaction kinetics. By comparing the maximum reaction rate (Vmax), Michaelis constant (Km) and turnover number (Kcat), the optimized PolyA probe was assessed and identified. In this work, the optimized PolyA-DNA probe exhibited an outstanding sensitivity in Salmonella typhimurium (S. ty) detection, which is 11.9 times and 4.6 times higher than those of the SH-DNA and the MCH treated SH-DNA. Meanwhile, a detection limit of 28.1 CFU mL-1 was achieved in Escherichia coli (E. coli) detection. Furthermore, the biosensor achieved good selectivity and high repeatability with recoveries of 91%-115% for real sample detection. Considering these advantages, this template has great potential as a routine tool for pathogen detection and has wide applications in the field of global public health and food safety.

A novel surface-enhanced Raman scattering (SERS) strategy for ultrasensitive detection of bacteria based on three-dimensional (3D) DNA walker.

Bacteria seriously endanger human life and health, and the detection of bacteria is vital for the prevention and treatment of related diseases. Surface-enhanced Raman scattering (SERS) is considered as a powerful technique for bacterial detection due to the inherent richness of spectral data. In this work, a novel SERS strategy based on three-dimensional (3D) DNA walker was developed for quantitative analysis of Salmonella typhimurium (S. ty). The complimentary DNA of S.ty-recognizing aptamer (cApt) was replaced from the double-stranded DNA (dsDNA) of Apt@cApt in the presence of S.ty, which can trigger the endonuclease mediated "DNA walker" on the surface of gold modified magnetic nanoparticles (AuMNPs). The DNA residues on the surface of AuMNPs can bind to SERS tag through base complementary pairing, and the complex of "AuMNPs@SERS tag" can be separated from the fluid by an external magnetic field for SERS analysis. It was found that the SERS intensity showed a good linear relationship with both lower (10-104 CFU/mL) and higher (104-106 CFU/mL) S.ty concentration. A superior limit of detection (LOD) as low as 4 CFU/mL was achieved due to the signal amplification effect of "DNA walker", and the preeminent selectivity of the proposed method was determined by the selectivity of the aptamer sequence. This strategy of separating the SERS tag from the biological matrix enables high stability and good repeatability of the SERS spectra, which presents a new method for SERS detection of biomaterials that can benefit various application scenarios.

Toehold-mediated strand displacement reaction formation of three-way junction DNA structure combined with nicking enzyme signal amplification for highly sensitive colorimetric detection of Salmonella Typhimurium.

The detection of Salmonella Typhimurium (S.typhimurium) is of great importance in food safety field. Colorimetric strategy is particularly appealing for S. typhimurium identification because of its user-friendliness and instrument-free. However, the existing colorimetric strategies still meet the challenges of low sensitivity, tedious nucleic acid extraction and expensive labeling processes. Herein, a high sensitivity and label-free colorimetric sensing strategy for S. typhimurium detection without nucleic acid extraction is constructed. Specifically, the proposed strategy is based on three-way junction (3WJ) DNA branched structure combined with nicking enzyme signal amplification (NESA). In the presence of target, cascaded signal amplification is initiated through a series of toehold-mediated strand displacement reactions (TSDRs) to recycle the trigger DNA causing formation of the numerous 3WJ DNA branched structures (3WJ-TSDRs). Then, the branches of 3WJ-TSDRs are fully utilized to hybridize with the DNAzyme signal probes to initiate NESA in the presence of Nt. BbvCI, which making every branch has a function of signal amplification. Finally, DNAzyme signal probes (green) were completely split into two fragments (colorless). The application of NESA in the branches of 3WJ-TSDRs offers a highly sensitive detection of S. typhimurium with a low limit of detection of 42 CFU mL-1. Besides, the colorimetric sensing strategy also shows strong anti-interference. The capability of the colorimetric sensing strategy in spiked samples was also investigated, showing a more intuitive results and fast detection in compare with the traditional plate counting method. With these characteristics, the proposed sensing strategy based on 3WJ-TSDRs and NESA is a promising tool for new point-of-care (POC) applications in food safety.

Effect of Winning Experience on Aggression Involving Dangerous Fighting Behavior in Anastatus disparis (Hymenoptera: Eupelmidae).

Aggressive behavior is widely observed in animal species for acquiring important resources and usually includes both dangerous and nondangerous fighting patterns. Only a few species show dangerous fighting patterns that are defined by fights ending with contestants being severely injured or killed. Prior experience, an important factor in many species, has been demonstrated to affect a contestant's subsequent fighting behavior. Few studies have focused on the effect of experience on aggression involving dangerous fighting patterns. Here, an egg parasitoid wasp, Anastatus disparis, which shows extreme and dangerous fighting behavior to acquire mating opportunities, was used as an experimental model. Our results showed that the fighting intensity of the winning males significantly decreased subsequent fighting behavior, which was inconsistent with general predictions. Transcriptomic analyses showed that many genes related to energy metabolism were downregulated in winners, and winners increased their fighting intensity after dietary supplementation. Our study suggested that fighting in A. disparis is a tremendous drain on energy. Thus, although males won at combat, significant reductions in available energy constrained the intensity of subsequent fights and influenced strategic decisions. In addition, winners might improve their fighting skills and abilities from previous contests, and their fighting intensity after dietary supplementation was significantly higher than that of males without any fighting experience. Generally, in A. disparis, although winners increased their fighting ability with previous experience, the available energy in winners was likely to be a crucial factor affecting the intensity and strategic decisions in subsequent fights.

Fabrication of functionalized magnetic microspheres based on monodispersed polystyrene for quantitation of allyl-benzodioxoles coupled with gas chromatography and mass spectrometry.

Monodispersed magnetic microspheres were synthesized by the magnetization of the aminized polystyrene cores and the subsequent polymerization of allyl glycidyl ether, divinylbenzene and N-vinyl-2-pyrrolidone, which exhibited excellent monodispersity in aqueous solution and high efficiency for allyl-benzodioxoles extraction. Various techniques, including scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FT-IR) and vibrating sample magnetometry (VSM) were employed to characterize the composites. Coupled with gas chromatography-mass spectrometry (GC-MS), a sensitive and simple magnetic solid phase extraction (MSPE) procedure based on the prepared microspheres was established for determination of allyl-benzodioxoles in cola-flavoured drinks. The factors affecting the extraction procedure, such as pH value, adsorbent amount, adsorption time, desorption solution and desorption time were optimized. The developed method was characterized by a high recovery (spiked at 5 µg L-1, 25 µg L-1 and 250 µg L-1), a low detection limit (0.05 µg L-1 for safrole and 0.08 µg L-1 for myristicin), a good linearity (correlation coefficients higher than 0.9990 for both) and a satisfactory repeatability (relative standard deviation below 3.7% for both, n = 3). The approach proposed here was confirmed to be fast and reliable for quantitative analysis of allyl-benzodioxoles in cola samples, especially at a trace level.