A dual-signal ratiometric electrochemical aptasensor based on Thi/Au/ZIF-8 and catalytic hairpin assembly for ultra-sensitive detection of aflatoxin B1.

A dual-signal ratiometric electrochemical aptasensor has been developed  for AFB1 detection using thionine/Au/zeolitic imidazolate framework-8 (Thi/Au/ZIF-8) nanomaterials and catalytic hairpin assembly (CHA) reaction. Thi/Au/ZIF-8 combined with DNA hairpin 2 (H2) was used as a signal probe. [Fe(CN)6]3-/4- was served as another signal probe, and the IThi/Au/ZIF-8/I[Fe(CN)6]3-/4- ratio was for the first time utilized to quantify AFB1. AFB1-induced CHA was used to expand the ratio of electrical signals. In the presence of AFB1, H2/Thi/Au/ZIF-8 bound to the electrode via CHA, enhanced  the current signal of Thi/Au/ZIF-8. H2 contained the DNA phosphate backbone hindered [Fe(CN)6]3-/4- redox reaction and resulted in a lower [Fe(CN)6]3-/4- current signal. This aptasensor exhibited high specificity for AFB1, a linear range of 0.1 pg mL-1 to 100 ng mL-1, and a detection limit of 0.089 pg mL-1. It demonstrated favorable sensitivity, selectivity, stability, and repeatability. The aptasensor was suitable for detecting AFB1 in peanuts and black tea and holds potential for real sample applications.

A novel fluorescent aptasensor based on 3D porous nitrogen-sulfur co-doped carbon mesh and hybridization chain reaction for sensitive detection of ochratoxin A.

A novel three-dimensional (3D) porous nitrogen-sulfur co-doped carbon (N-S-C) mesh was synthesized and used for the first time as the quenching material to construct a fluorescent aptasensor for ochratoxin A (OTA) detection. The fluorescent aptasensor with enzyme-free signal amplification strategy was developed by using cDNA as a promoter to trigger hybridization chain reaction (HCR), which effectively improved the sensitivity of this aptasensor. In the absence of OTA, 3D porous N-S-C mesh can adsorb carboxyfluorescein FAM-labeled hairpin DNA1 (H1-FAM) and hairpin DNA2 (H2) and quench the fluorescence of FAM. In the presence of the OTA, the OTA specifically binds to the aptamer strand and the DNA duplex undergoes dissociation. The released cDNA in turn serves as a promoter for HCR, and the strand assembly of H1-FAM and H2 is triggered by the promoter to generate long-strand DNA polymers via HCR, resulting in an increasing fluorescent signal. Under optimal conditions, there was a good linear relationship between lgCOTA and fluorescence intensity difference in the range 0.01-500 ng/mL (R2 = 0.993), and the detection limit was 2.7 pg/mL. The designed sensor platform was applied to determine spiked OTA in peanut, wheat flour, corn flour, black tea, and wine with recoveries in the range of 94.4-119.6%.

The importance of rest phase and pollutant removal mechanism of tidal flow constructed wetlands (TFCW) in rural grey water treatment.

This paper explored the effects of the rest phase of tidal flow constructed wetlands (TFCW) on pollutant removal and microbial communities, and further analyzed the mechanism of TFCW removal of pollutants from grey water. The results showed that the removal rate of organic matter was 69.91 ± 2.44% in the control group (NR-TFCW) without the rest phase, 94.95 ± 1.17% in the experimental group (TFCW), and 96.95 ± 2.43% in the control group (P-TFCW) with the ventilation pipe enhanced rest phase. Limiting and enhancing the oxygen supply in the emptying stage of TFCW will enhance the overlap rate of microorganisms in the upper, middle and lower layers of the reactor. Enhancing the rest phase of TFCW leaded to better aerobic removal of organic matter in the microbial community, while limiting the rest phase of TFCW results in the opposite. In addition, the species overlap rate of the top, middle and bottom layers of NR-TFCW (69.98%) and P-TFCW (54.29%) was higher than that of TFCW (11.34%). The removal of organic matter by TFCW mainly relied on the adsorption of biochar in the flood phase, and the microorganisms aerobic degraded the organic matter adsorbed on the biochar in the rest phase. And thus form a continuous cycle of adsorption and biological regeneration. The microbial community in TFCW did not have the ability to nitrify, but had the ability to remove phosphorus. Ammonia nitrogen in the influent was adsorbed by biochar or converted into cytoplasm. While the phosphorus in the influent was adsorbed by the biochar, it was also being biologically removed.

MiR-21-5p/dual-specificity phosphatase 8 signalling mediates the anti-inflammatory effect of haem oxygenase-1 in aged intracerebral haemorrhage rats.

Intracerebral haemorrhage (ICH) is a severe neurological disorder caused by bleeding within the brain tissue. Inflammation has been implicated in ICH pathogenesis and is a potential therapeutic target for ICH. Haemin, an activator of haem oxygenase-1 (HO-1), rapidly increases HO-1 protein expression and activity and has been shown to distinctly affect anti-inflammatory functions after central nervous system (CNS) injury. However, less is known about the mechanisms that underlie the anti-inflammatory effects of haemin in aged rats post-ICH. Here, we performed microarray analysis to identify miRNAs that respond strongly to HO-1 regulation in ICH rats and found that miR-21-5p induced the most significant change. Using Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment and Gene Ontology (GO) analysis, we focused on dual-specificity phosphatase 8 (DUSP8) from the predicted miR-21-5p targets. Luciferase reporter assays confirmed that miR-21-5p bound directly to DUSP8. MiR-21-5p upregulation in vitro downregulated DUSP8 expression. Importantly, intracerebroventricularly injecting antagomir for miR-21-5p (A-miR-21-5p), which was used to inhibit miR-21-5p in aged ICH rats, significantly reduced the neurological defects, repaired cognitive impairment, alleviated blood-brain barrier (BBB) permeability, inhibited neuronal apoptosis posthaemorrhage and accelerated haematoma absorption. In addition, serum miR-21-5p levels were notably elevated in patients relative to healthy individuals and were correlated with National Institutes of Health Stroke Scale (NIHSS) scores and clinical outcomes. In summary, A-miR-21-5p increased HO-1 expression in cerebral haematomas, thus eliciting the DUSP8-modulated perifocal neuroprotective effect of haemin. MiR-21-5p with haemin therapy may be a potential therapy post-ICH.

Effects of different doses of dexmedetomidine on analgesic efficacy and inflammatory cytokines in patients undergoing laparoscopic surgery.

The effects of different doses of dexmedetomidine on analgesic efficacy and inflammatory cytokines in patients with laparoscopic surgery were investigated. A total of 179 laparoscopic patients from March 2015 to May 2017 were enrolled and randomly divided into the control group (group A) and three experimental groups with different doses of dexmedetomidine (group B: 0.25; group C: 0.5 and group D: 1 µg/kg). Results showed that there was no significant difference between the four groups in the operation time, the amount of surgical bleeding and intraoperative fluid infusion. The VAS score of group A was significantly higher than the other three groups. In addition, the VAS score of group D at each time-point was the lowest. There was no significant difference regarding the agitation score and sedation score between group A and group B. Furthermore, the restlessness score and sedation score in group C were significantly lower than those in group A and group B. Next we found that CRP and TNF-α in group A and group B were significantly higher than those in groups C and D. In addition, IL-10 in group D was significantly higher than that in group C. Moreover, patients in group C had the least adverse reaction effects. In conclusion, medium dosage of dexmedetomidine cannot only effectively relieve the pain of laparoscopic patients but also regulate the secretion of inflammatory cytokines.

Thrombin-induced, TNFR-dependent miR-181c downregulation promotes MLL1 and NF-κB target gene expression in human microglia.

BACKGROUND: Controlling thrombin-driven microglial activation may serve as a therapeutic target for intracerebral hemorrhage (ICH). Here, we investigated microRNA (miRNA)-based regulation of thrombin-driven microglial activation using an in vitro thrombin toxicity model applied to primary human microglia. METHODS: A miRNA array identified 22 differential miRNA candidates. Quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) identified miR-181c as the most significantly downregulated miRNA. TargetScan analysis identified mixed lineage leukemia-1 (MLL1) as a putative gene target for miR-181c. qRT-PCR was applied to assess tumor necrosis factor-alpha (TNF-α), miR-181c, and MLL1 levels following thrombin or proteinase-activated receptor-4-specific activating peptide (PAR4AP) exposure. Anti-TNF-α antibodies and tumor necrosis factor receptor (TNFR) silencing were employed to test TNF-α/TNFR dependence. A dual-luciferase reporter system and miR-181c mimic transfection assessed whether mir-181c directly binds to and negatively regulates MLL1. Nuclear factor kappa-B (NF-κB)-dependent luciferase reporter assays and NF-κB target gene expression were assessed in wild-type (MLL1+) and MLL1-silenced cells. RESULTS: Thrombin or PAR4AP-induced miR-181c downregulation (p < 0.05) and MLL1 upregulation (p < 0.05) that were dependent upon TNF-α/TNFR. miR-181c decreased wild-type MLL1 3'-UTR luciferase reporter activity (p < 0.05), and a miR-181c mimic suppressed MLL1 expression (p < 0.05). Thrombin treatment increased, while miR-181c reduced, NF-κB activity and NF-κB target gene expression in both wild-type (MLL1+) and MLL1-silenced cells (p < 0.05). CONCLUSIONS: Thrombin-induced, TNF-α/TNFR-dependent miR-181c downregulation promotes MLL1 expression, increases NF-κB activity, and upregulates NF-κB target gene expression. As miR-181c opposes thrombin's stimulation of pro-inflammatory NF-κB activity, miR-181c mimic therapy may show promise in controlling thrombin-driven microglial activation following ICH.

A "three-in-one" sample preparation method for simultaneous determination of B-group water-soluble vitamins in infant formula using VitaFast(®) kits.

VitaFast(®) test kits designed for the microbiological assay in microtiter plate format can be applied to quantitative determination of B-group water-soluble vitamins such as vitamin B12, folic acid and biotin, et al. Compared to traditional microbiological methods, VitaFast(®) kits significantly reduce sample processing time and provide greater reliability, higher productivity and better accuracy. Recently, simultaneous determination of vitamin B12, folic acid and biotin in one sample is urgently required when evaluating the quality of infant formulae in our practical work. However, the present sample preparation protocols which are developed for individual test systems, are incompatible with simultaneous determination of several analytes. To solve this problem, a novel "three-in-one" sample preparation method is herein developed for simultaneous determination of B-group water-soluble vitamins using VitaFast(®) kits. The performance of this novel "three-in-one" sample preparation method was systematically evaluated through comparing with individual sample preparation protocols. The experimental results of the assays which employed "three-in-one" sample preparation method were in good agreement with those obtained from conventional VitaFast(®) extraction methods, indicating that the proposed "three-in-one" sample preparation method is applicable to the present three VitaFast(®) vitamin test systems, thus offering a promising alternative for the three independent sample preparation methods. The proposed new sample preparation method will significantly improve the efficiency of infant formulae inspection.

Comparative evaluation of a phage protein ligand assay with VIDAS and BAX methodology for detection of Escherichia coli O157:H7 using a standard nonproprietary enrichment broth.

Escherichia coli O157:H7 is a major foodborne pathogen of concern worldwide. This study was conducted to compare the sensitivity and minimum enrichment time for detection of E. coli O157:H7 by the VIDAS ultraperformance E. coli test (VIDAS ECPT UP) with that of two other commercial detection kits, the ELISA-based VIDAS ECO system and the PCR-based BAX system. Only VIDAS ECPT UP detected all 18 positive results of bacterial suspensions at the level of 10(4) CFU/mL E. coli O157:H7 and 10(6) CFU/mL E. coli as background flora, whereas the BAX system PCR assay detected six positive results and VIDAS ECO detected no positive results. A 6 h enrichment at 42 degrees C is enough for detection of all 18 strains in artificial contaminated raw beef meat, raw milk, and raw chicken, and for detection of most of them in soybean sprout and fresh papaya juice with VIDAS ECPT UP, whereas enrichment of more than 8 h was required for detection of the strains with the VIDAS ECO and PCR-BAX systems. These results indicate that the VIDAS ECPT UP is superior to the other two alternative methods when a standard enrichment broth is used that is different from the broths recommended by the manufacturers.

[Amplification of Ds flanking sequences from rice genomic DNA of hybrids of Ac x Ds lines and the analysis of Ds insertions].

Ac and Ds insertions among the genomic DNAs of hybrids of Ac x Ds lines were screened by PCR. The genomic DNAs, which were proved to harbour both Ac and Ds, were used as templates in TAIL-PCR to clone the Ds flanking sequences. The cloned specific fragments were sequenced, and the sequenced Ds flanking sequences were used as query sequences to perform on-line sequence comparing analysis against GenBank by employing BLAST program of NCBI. The information about the chromosome location of Ds-inserted genes, or genes immediately downstream of the inserted sites, and their functional innotations were achieved. Based on the analysis from the cloned 93 Ds-flanking sequences, it was found that 21 hybrid plants had Ds insertions in genic regions, whereas the remaining 72 samples's intergenic regions were inserted by Ds element. Moreover, among the 72 regions, 12 were inserted immediately upstream (within 3 kb) of specific genes. Also, the strategies to improve the performance in cloning the Ds flanking sequences and in screening the Ac/Ds lines were emphasized.

[Induction of protective immunity against Schistosoma japonicum by pcDNA3.1/Sj20.8 nucleic acid vaccine in BALB/c mice].

Sj20.8 gene was amplified by PCR and inserted into eukaryotic expression plasmid pcDNA3.1 to construct recombinant plasmid pcDNA3.1/Sj20.8, which was then injected into the quadriceps femoris of the BALB/c mice. Results showed that the Sj20.8 antigen was low expressed in the local tissue of the mice, and was not able to significantly reduce eggs in the liver than in the control mice.

[Acquisition and analysis of 149 ESTs and 18 novel genes of Schistosoma japonicum].

OBJECTIVE: To acquire and analyze adult stage Schistosoma japonicum (Chinese strain) expressed sequence tags and new genes from an adult S. japonicum cDNA library, and to search new vaccine candidates and drug targets. METHODS: A cDNA library was constructed from adult stage S. japonicum. Clones were selected randomly from the cDNA library and were sequenced. ESTs and new genes were acquired after analysis in GenBank databases by BLAST and other programs. All ESTs and new genes were submitted to GenBank and received accession numbers. RESULTS: 149 ESTs were acquired from a total 382 clones that were randomly selected from the adult S. japonicum cDNA library. All ESTs were successfully submitted to the dbEST at Genbank. Some of them were homologous with sequences of male, female, egg, schistosomula, cercaria and miracidia of S. japonicum. 18 new genes of adult S. japonicum were acquired. Some genes were housekeeping genes and some genes might be interesting as vaccine candidates or drugs targets. CONCLUSIONS: The EST strategy is a rapid, efficient and economical method to acquire ESTs and to discover new genes of adult stage S. japonicum from cDNA libraries.

Influences of nano-TiO2 on the chloroplast aging of spinach under light.

The effects of nano-TiO2 (rutile) on the chloroplast aging of spinach under light were studied. The results showed that when the chloroplasts were illuminated for 1, 5, and 10 min with 500 micromol/cm2/min light intensity, respectively, the evolution oxygen rate was rapidly increased; when the chloroplasts were treated for 20, 30, and 40 min with 500 micromol/cm2/min light intensity, respectively, the evolution oxygen rate was gradually decreased. While spinach was treated with 0.25% nano-TiO2, the rate of evolution oxygen of chloroplasts in different illumination times (1, 5, 10, 20, 30, and 40 min) was higher than that of control, and when the illumination time was over 10 min, the reduction of the evolution oxygen rate was lower than that of control. It suggested that nano-TiO2 treatment could protect chloroplasts from aging for long-time illumination. The mechanism researches indicated that nano-TiO2 treatment could significantly increase the activities of superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD), decrease accumulation of reactive oxygen free radicals and the level of malondialdehyde (MDA), and maintain stability of membrane structure of chloroplast under light.