Characteristic Evaluation of Gas Chromatography with Different Detectors for Accurate Determination of Sulfur Hexafluoride.

Sulfur hexafluoride (SF6), which survives in the atmosphere for an extremely long period of time, is the most potent greenhouse gas regulated under the Kyoto Protocol. So, the accurate monitoring of atmospheric SF6 plays an important role in the study of the control policies for reducing greenhouse gas emissions. The instruments for SF6 measurement are typically calibrated using certified reference materials. The concentrations of the commercially available SF6 reference materials usually have a broad range, from 1 µmol/mol to 6000 µmol/mol. Some characteristics including sensitivity, linear range, relative standard deviation, and accuracy are crucial for the determination of SF6 in such a broad concentration range. Therefore, the selection of a proper detector for the accurate determination of SF6 with such a broad range is extremely important to establish a gas chromatography (GC) method for developing SF6 reference materials. In this paper, several typical GC methods with different detectors, including a thermal conductivity detector (TCD), a pulsed discharge helium ionization detector (PDHID), and a flame photometric detector (FPD), were carefully established for the accurate determination of SF6 with different concentrations. The results show that an FPD detector has a relatively narrow linearity range, thus a quadratic equation should be established for building a calibration curve. The PDHID and TCD have good linearity with coefficients of 1.0000 in the concentration range of 10-100 µmol/mol (using a PDHID), and 100-1000 µmol/mol (using a TCD), respectively. Further considering the measurement errors of indication results, the PDHID is suitable for SF6 measurement when the concentrations are below 100 µmol/mol, whereas the TCD is suitable for SF6 measurement when the concentrations are over 100 µmol/mol. These results provide useful guidance in choosing an appropriate GC detector for the accurate determination of SF6, which are especially very helpful for developing SF6 reference materials.

Functional analysis of differentially expressed long non-coding RNAs in DENV-3 infection and antibody-dependent enhancement of viral infection.

Dengue fever, as a mosquito-borne viral disease widely spread in tropical and subtropical regions, remarkably threatens public health, while the mechanism involved in host-DENV interaction has not been fully elucidated. Firstly, we analyzed the expression levels of long non-coding RNAs (lncRNAs) in THP-1 cells after DENV-3 infection and Antibody- Dependent Enhancement of viral infection (ADE-VI) by RNA-Seq. Secondly, through the RT-qPCR to confirm those differentially expressed (DE) lncRNAs. Then, we also analyzed the competitive endogenous RNA (CeRNA) regulatory network of DE lncRNAs. Finally, we predicted the encode ability of DE lncRNAs. It was found that on the X and Y chromosomes, the expression levels of lncRNAs in THP-1 cells after ADE-VI were significantly different from those in the negative control and the DENV-3 infection groups. There were 71 DE lncRNAs after DENV-3 infection, including 42 up-regulated and 29 down-regulated lncRNAs. A total of 70 DE lncRNAs after ADE-VI were detected, including 38 up-regulated and 32 down- regulated lncRNAs. After ADE-VI and DENV-3 infection, there were 35 DE lncRNAs, including 11 up-regulated and 24 down-regulated lncRNAs. The analysis of the CeRNA regulatory network of DE lncRNAs revealed that, TRIM29, STC2, and IGFBP5 were correlated with the ADE-VI. Additionally, it was found that lncRNAs not only participated in the CeRNA regulatory network, but also maybe encoded small peptides. Our findings provided clues for further investigation into the lncRNAs associated antiviral mechanism of ADE-VI and DENV-3 infection.

Sweeping analysis of transcript profile in dengue virus serotype 3 infection and antibody-dependent enhancement of infection.

Dengue virus infection mainly causes dengue hemorrhagic fever (DHF) and/or dengue shock syndrome (DSS). However, ADE (antibody-dependent enhancement) is one of the main pathogenic factors, and its pathogenic mechanism has not been fully elucidated. Recently, with the development of high-throughput sequencing, an increased number of RNAs have been confirmed to play a vital regulatory role in the process of virus infection. However, there is a lack of research on dengue virus infection and ADE. In this study, we used RNA-Seq to detect differentially expressed RNAs (DE RNAs) profiles in mock-infected, DENV-3-infected, and ADE-infected THP-1 cells. Firstly, we found 69 circRNAs, 259 miRNAs, and 18 mRNAs were differentially expressed in THP-1 vs DENV-3. In THP-1 vs ADE, 94 circRNAs, 263 miRNAs, and 111 mRNAs were differentially expressed. In DENV-3 vs ADE, 68 circRNAs, 105 miRNAs, and 94 mRNAs were differentially expressed. Functional enrichment analysis of these DE RNAs mainly focused on immune system, viral infectious diseases, cytokine-cytokine receptor interactions, and NOD/RIG-I-like receptor signaling pathways. In DENV-3 vs ADE, notably, the expression of HBB was up-regulated, which was a Fcγ Receptor-mediated phagocytosis protein. Additionally, we predicted the encoding ability of DE circRNAs, and it was found that a small peptide was encoded by novel_circ_001562 and that its amino acid sequence was consistent with that of DDX60L, which is a class of interferon-stimulated genes. Finally, we constructed the ceRNA regulatory network pathway. Therefore, our study provides a new strategy for further investigation on DENV-host interactions.