An electrochemiluminescence resonance energy transfer biosensor based on CDs/PAMAM/rGO nanocomposites and Au@Ag2S nanoparticles for PML/RARα fusion gene detection.

In recent years, electrochemiluminescence resonance energy transfer (ECL-RET) with low background signal and high specificity has attracted much attention among researchers. Herein, we established a novel ECL-RET biosensor for PML/RARα fusion gene detection. In this ECL-RET system, carbon dots (CDs) with low toxicity and prominent electrochemical activity were used as donor and Au@Ag2S core-shell nanoparticles (Au@Ag2S NPs) were employed as ECL acceptor. The Au@Ag2S NPs possessed a wide ultraviolet-visible (UV-vis) absorption spectrum between 500 nm and 700 nm, which completely overlapped with the ECL spectrum of CDs. Furthermore, the CDs-decorated poly-amidoamine/reduced graphene oxide (CDs/PAMAM/rGO) nanocomposites were prepared to improve the ECL signals and served as a substrate to stably load capture probe deoxyribonucleic acid (DNA). Based on the ECL-RET biosensing strategy, the Au@Ag2S NPs-labeled assistant probes and target DNA could pair with capture probes to form the sandwich-type DNA structure and the distance between donor and accepter was closed, leading to quenching of the ECL signal of CDs. The ECL-RET biosensor represented eminent analytical performance for PML/RARα fusion gene detection with a wide linear relationship from 5 fM to 500 pM and a low detection limit of 0.72 fM, which provided a novel technical means and theoretical basis for detection and diagnosis of acute promyelocytic leukemia.

A Y-shape-structured electrochemiluminescence biosensor based on carbon quantum dots and locked nucleic acid probe for microRNA determination with single-base resolution.

Since microRNAs (miRNAs) are predictors of tumorigenesis, accurate identification and quantification of miRNAs with highly similar sequences are expected to reflect tumor diagnosis and treatment. In this study, a highly selective and sensitive electrochemiluminescence (ECL) biosensor was constructed for miRNAs determination based on Y-shaped junction structure equipped with locked nucleic acids (LNA), graphene oxide-based nanocomposite to enrich luminophores, and conductive matrix. Specifically, two LNA-modified probes were designed for specific miRNA recognition, that is, a dual-amine functionalized hairpin capture probe and a signal probe. A Y-shaped DNA junction structure was generated on the electrode surface upon miRNA hybridizing across the two branches, so as to enhance the selectivity. Carbon quantum dots-polyethylene imine-graphene oxide (CQDs-PEI-GO) nanocomposites were developed to enrich luminophores CQDs, and thus enhancing the ECL intensity. For indirect signal amplification, an electrochemically activated poly(2-aminoterephthalic acid) (ATA) film decorated with gold nanoparticles was prepared on electrode as an effective matrix to accelerate the electron transfer. The fabricated ECL biosensor achieved sensitive determination of miRNA-222 with a limit-of-detection (LOD) as low as 1.95 fM (S/N = 3). Notably, Y-shaped junction structures equipped with LNA probes endowed ECL biosensor with salient single-base discrimination ability and anti-interference capacity. Overall, the proposed Y-shaped ECL biosensor has considerable promise for clinical biomarker determination.

TRIM11 protects against tauopathies and is down-regulated in Alzheimer's disease.

Aggregation of tau into filamentous inclusions underlies Alzheimer's disease (AD) and numerous other neurodegenerative tauopathies. The pathogenesis of tauopathies remains unclear, which impedes the development of disease-modifying treatments. Here, by systematically analyzing human tripartite motif (TRIM) proteins, we identified a few TRIMs that could potently inhibit tau aggregation. Among them, TRIM11 was markedly down-regulated in AD brains. TRIM11 promoted the proteasomal degradation of mutant tau as well as superfluous normal tau. It also enhanced tau solubility by acting as both a molecular chaperone to prevent tau misfolding and a disaggregase to dissolve preformed tau fibrils. TRIM11 maintained the connectivity and viability of neurons. Intracranial delivery of TRIM11 through adeno-associated viruses ameliorated pathology, neuroinflammation, and cognitive impairments in multiple animal models of tauopathies. These results suggest that TRIM11 down-regulation contributes to the pathogenesis of tauopathies and that restoring TRIM11 expression may represent an effective therapeutic strategy.

Flower-like molybdenum disulfide/cobalt ferrite composite for the extraction of benzotriazole UV stabilizers in environmental samples.

Benzotriazole UV stabilizers (BUVSs) are a class of emerging contaminants of concern; the development of rapid and convenient monitoring method for these trace-level pollutants in waters is of crucial significance in environmental science. Here, a novel magnetic flower-like molybdenum disulfide/cobalt ferrite nanocomposite (MoS2/CoFe2O4) was synthesized by hydrothermal reaction. Compared with the conventional Fe3O4-based magnetic composites, the proposed material just required a minimum consumption of Co/Fe towards the equivalent of MoS2 while providing superior magnetization performance. Taking advantages of high adsorption capacity, extraordinary stability, and repeatability in construction, MoS2/CoFe2O4 was applied to the extraction to BUVSs. The enrichment factors of three BUVSs were in the range 164-193 when 20 mL of environmental water sample was loaded on 40 mg of the adsorbent. MoS2/CoFe2O4 could be regenerated and recycled at least 10 cycles of adsorption/desorption with recoveries of 80.1-111%. The method of MoS2/CoFe2O4-based extraction coupled with high-performance liquid chromatography-variable wavelength detector was applied to the monitoring of BUVSs in seawater, lake water, and wastewater, which gave detection limits (S/N = 3) of 0.023-0.030 ng·mL-1 and recoveries of 80.1-110%. The intra-day and inter-day precisions (relative standard deviation, RSDs, n = 3) were in the range 1.6-7.5% and 3.2-11.5%, respectively. The approach is an alternative for efficient and sensitive extraction and determination of trace-level environmental pollutants in waters.

Efficient Determination of PML/RARα Fusion Gene by the Electrochemical DNA Biosensor Based on Carbon Dots/Graphene Oxide Nanocomposites.

PURPOSE: The PML/RARα fusion gene as a leukemogenesis plays a significant role in clinical diagnosis of the early stage of acute promyelocytic leukemia (APL). Here, we present an electrochemical biosensor for PML/RARα fusion gene detection using carbon dots functionalized graphene oxide (CDs/GO) nanocomposites modified glassy carbon electrode (CDs/GO/GCE). MATERIALS AND METHODS: In this work, the CDs/GO nanocomposites are produced through π-π stacking interaction and could be prepared in large quantities by a facile and economical way. The CDs/GO nanocomposites were decorated onto electrode surface to improve the electrochemical activity and as a bio-platform attracted the target deoxyribonucleic acid (DNA) probe simultaneously. RESULTS: The CDs/GO/GCE was fabricated successfully and exhibits high electrochemical activity, good biocompatibility, and strong bioaffinity toward the target DNA sequences, compared with only the pristine CDs on GCE or GO on GCE. The DNA biosensor displays excellent sensing performance for detecting the relevant pathogenic DNA of APL with a detection limit of 83 pM (S/N = 3). CONCLUSION: According to the several experimental results, we believe that the simple and economical DNA biosensor has the potential to be an effective and powerful tool for detection of pathogenic genes in the clinical diagnosis.

In-situ fabrication of zeolite imidazole framework@hydroxyapatite composite for dispersive solid-phase extraction of benzodiazepines and their determination with high-performance liquid chromatography-VWD detection.

A novel zeolite imidazole framework@hydroxyapatite composite (ZIF-8@HAP) was constructed via in-situ growth and developed for efficient dispersive solid-phase extraction (DSPE) of three benzodiazepines from urine samples. The prepared composite was characterized by scanning electron microscopy, energy-dispersive spectrometer, Fourier-transform infrared spectrometry, X-ray diffractometry, zeta potential analyzer, and nitrogen adsorption-desorption experiment. Characterization results showed typical dodecahedron ZIF-8 crystals that were uniformly located on the surface of rod-like HAP. The combination of ZIF-8 and HAP made the surface area significantly enhanced from 4.68 to 205.44 m2 g-1. Compared with a commercial C18 adsorbent, ZIF-8@HAP exhibited superior removal performance for interfering components from urine and offered better extraction properties for the analytes. The prepared ZIF-8@HAP was applied as an adsorbent in DSPE, and the main experimental parameters, including pH and ionic strength of solution, adsorbent amount, adsorption time, elution solvent, and volume, were investigated. Under optimal conditions, the adsorption for 250 ng mL-1 of each analyte in 4 mL of urine was accomplished within 2 min using 60 mg of adsorbent. The method of ZIF-8@HAP-based DSPE followed by high-performance liquid chromatography gave enhancement factors of 13.3-15.3, linear ranges of 2.5-500 ng mL-1, and limits of detection (S/N = 3) of 0.7-1.4 ng mL-1. The relative recoveries at three spiked levels ranged from 88.7 - 102% with intra-day and inter-day precisions from 3.0 - 10.3% and 2.3 - 12.3%, respectively. These results indicated that the proposed strategy had promising applicability for convenient, rapid, and efficient determination of benzodiazepines in urine samples.Graphical abstract In-situ fabrication of ZIF-8@HAP composite for dispersive solid-phase extraction of benzodiazepines in urine samples.

Ubiquitination and functional modification of GluN2B subunit-containing NMDA receptors by Cbl-b in the spinal cord dorsal horn.

N-methyl-d-aspartate (NMDA) glutamate receptors (NMDARs) containing GluN2B subunits are prevalent early after birth in most brain regions in rodents. Upon synapse maturation, GluN2B is progressively removed from synapses, which affects NMDAR function and synaptic plasticity. Aberrant recruitment of GluN2B into mature synapses has been implicated in several neuropathologies that afflict adults. We found that the E3 ubiquitin ligase Cbl-b was enriched in the spinal cord dorsal horn neurons of mice and rats and suppressed GluN2B abundance during development and inflammatory pain. Cbl-b abundance increased from postnatal day 1 (P1) to P14, a critical time period for synapse maturation. Through its N-terminal tyrosine kinase binding domain, Cbl-b interacted with GluN2B. Ubiquitination of GluN2B by Cbl-b decreased the synaptic transmission mediated by GluN2B-containing NMDARs. Knocking down Cbl-b in vivo during P1 to P14 led to sustained retention of GluN2B at dorsal horn synapses, suggesting that Cbl-b limits the synaptic abundance of GluN2B in adult mice. However, peripheral inflammation induced by intraplantar injection of complete Freund's adjuvant resulted in the dephosphorylation of Cbl-b at Tyr363, which impaired its binding to and ubiquitylation of GluN2B, enabling the reappearance of GluN2B-containing NMDARs at synapses. Expression of a phosphomimic Cbl-b mutant in the dorsal horn suppressed both GluN2B-mediated synaptic currents and manifestations of pain induced by inflammation. The findings indicate a ubiquitin-mediated developmental switch in NMDAR subunit composition that is dysregulated by inflammation, which can enhance nociception.

Ubiquitination and inhibition of glycine receptor by HUWE1 in spinal cord dorsal horn.

Glycine receptors (GlyRs) are pentameric proteins that consist of α (α1-α4) subunits and/or ß subunit. In the spinal cord of adult animals, the majority of inhibitory glycinergic neurotransmission is mediated by α1 subunit-containing GlyRs. The reduced glycinergic inhibition (disinhibition) is proposed to increase the excitabilities and spontaneous activities of spinal nociceptive neurons during pathological pain. However, the molecular mechanisms by which peripheral lesions impair GlyRs-α1-mediated synaptic inhibition remain largely unknown. Here we found that activity-dependent ubiquitination of GlyRs-α1 subunit might contribute to glycinergic disinhibition after peripheral inflammation. Our data showed that HUWE1 (HECT, UBA, WWE domain containing 1), an E3 ubiquitin ligase, located at spinal synapses and specifically interacted with GlyRs-α1 subunit. By ubiquitinating GlyRs-α1, HUWE1 reduced the surface expression of GlyRs-α1 through endocytic pathway. In the dorsal horn of Complete Freund's Adjuvant-injected mice, shRNA-mediated knockdown of HUWE1 blunted GlyRs-α1 ubiquitination, potentiated glycinergic synaptic transmission and attenuated inflammatory pain. These data implicated that ubiquitin modification of GlyRs-α1 represented an important way for peripheral inflammation to reduce spinal glycinergic inhibition and that interference with HUWE1 activity generated analgesic action by resuming GlyRs-α1-mediated synaptic transmission.

[Particle Size Distribution and Human Health Risk Assessment of Heavy Metals in Atmospheric Particles from Beijing and Xinxiang During Summer].

Under a condition of good air quality (AQI:55-90, PM10:37-97 µg·m-3, PM2.5:17-76 µg·m-3), six groups of 54 samples were collected using an Andersen cascade impactor from both the indoor and outdoor stations in Beijing and Xinxiang from June to August in 2016. The samples were digested by microwave digestion, and nine heavy metal elements (Pb, Cr, Ni, Cu, Zn, As, Cd, Mn, and Co) in the atmospheric particles were determined with an inductively coupled plasma source mass spectrometer (ICP-MS). The results showed that the enrichment index (0-3) of most elements were low in both cities except for Cd[15.0 (Beijing) and 8.47 (Xinxiang)]. Cr, Co, Cu, and Mn in the atmospheric particles from Beijing park, Cd, Pb, and Mn in the atmospheric particles from the Beijing office, Cr, Co, Ni, and As in the atmospheric particles from Xinxiang park, and all nine heavy metal elements in the atmospheric particles from roads in both cities were found to be more concentrated in the coarse fractions; however, Pb, Zn, Cd, Ni, and As in the atmospheric particles from Beijing park, Co, Zn, Ni, Cr, As, and Cu in the atmospheric particles from the Beijing office, Pb, Zn, Cd, Cu, and Mn in the atmospheric particles from Xinxiang park, and all nine metal elements in the atmospheric particles from the Beijing office showed the opposite pattern. The result of a human health risk assessment indicated that the carcinogenic risk of the five carcinogenic elements were all less than 10-4, but a lower potential cancer risk would also occur under long term exposure. For the four non-carcinogenic elements (Pb, Zn, Mn, and Cu), the non-carcinogenic health risk values of Pb, Zn, Mn, and Cu in the atmospheric particulates in Beijing were all far less than 1, which means the corresponding non-carcinogenic risk was negligible; and, except for Mn, there was no obvious non-carcinogenic risk from Pb, Zn, and Cu in the atmospheric particles of Xinxiang.

Disruption of SHP1/NMDA receptor signaling in spinal cord dorsal horn alleviated inflammatory pain.

Src-homology 2 domain-containing protein tyrosine phosphatase-1 (SHP1) is one of the non-receptor-like phosphatases that are highly enriched in hematopoietic cells. Although accumulating evidence has implicated the protein tyrosine phosphatases in the regulation of nociceptive transmission and plasticity, it is largely unknown whether SHP1 was expressed in pain-related spinal cord dorsal horn and engaged in the synaptic modification of nociceptive signals. Here we found that SHP1 was present in spinal neurons of rats and functionally coupled to GluN2A subunit-containing N-methyl-d-aspartate subtype of glutamate receptors, one of the key players in central sensitization of nociceptive behaviors. SHP1 interacted with a membrane-proximal region within the cytoplasmic tail of GluN2A. This interaction was necessary to stimulate SHP1 activity and more importantly, restrict SHP1 signaling to specifically enhance the tyrosine phosphorylation of GluN2A during inflammatory pain. Electrophysiological and behavioral studies showed that SHP1 binding potentiated GluN2A currents and evoked GluN2A-dependent pain hypersensitivity. The siRNA-mediated knockdown of SHP1 or interference with SHP1/GluN2A interaction by a synthetic peptide alleviated inflammatory pain induced by either Complete Freund's Adjuvant or formalin. Our data implicated that SHP1 was a specific enhancer of GluN2A-mediated nociceptive synaptic transmission in spinal cord dorsal horn, and manipulation of SHP1 activity may serve as an effective strategy for the treatment of inflammatory pain.

[Evaluation of an indirect immunofluorescence assay kit for the detection of anti-Toxoplasma gondii IgG].

OBJECTIVE: To develop an indirect immunofluorescence assay (IFA) kit for detecting anti-Toxoplasma gondii IgG. METHODS: Based on the established IFA method, we established an IFA kit for the detection of human T. gondii infection. The optimal working concentrations of T. gondii IgG-positive human serum and FITC-labeled goat anti-human IgG antibody were determined. Sensitivity, specificity, reproducibility, and storage period of this kit were studied, and compared with an imported kit. RESULTS: The optimal working concentration of T. gondii IgG-positive human serum and FITC-labeled goat anti-human IgG antibody was 1:40 and 1:100, respectively. The maximum dilution of T. gondii IgG-positive human serum that the kit can detect was 1:640. No cross reaction was observed with sera from patients with vivax malaria, falciparum malaria, schistosomiasis, echinococcosis, or cysticercosis. Cross reaction was observed to the rheumatoid factor positive sera. The sensitivity, specificity, positive predictive value, negative predictive value, concordance, Youden index of this kit was 90.9%, 100%, 100%, 96.2%, 97.2%, and 0.91, respectively; and that of the imported kit was 100%, 98%, 95.7%, 100%, 98.6%, and 0.98, respectively. There was no significant difference in sensitivity and specificity between the two kits (P > 0.05). CONCLUSION: The IFA kit shows adequate sensitivity and specificity for detection of anti-T. gondii IgG.