RESUMEN
Transcription of the covalently closed circular DNA (cccDNA) of hepatitis B virus (HBV) is subject to dual regulation by host factors and viral proteins. MicroRNAs (miRNAs) can regulate the expression of target genes at the post-transcriptional level. Systematic investigation of miRNA expression in HBV infection and the interaction between HBV and miRNAs may deepen our understanding of the transcription mechanisms of HBV cccDNA, thereby providing opportunities for intervention. miRNA sequencing and real-time quantitative PCR (qRT-PCR) were used to analyze miRNA expression after HBV infection of cultured cells. Clinical samples were analyzed for miRNAs and HBV transcription-related indicators, using qRT-PCR, enzyme-linked immunoassay (ELISA), and Western blot. miRNA mimics or inhibitors were used to study their effects on the HBV life cycle. The target genes of miR-3188 and their roles in HBV cccDNA transcription were also identified. The expression of 10 miRNAs, including miR-3188, which was significantly decreased after HBV infection, was measured in clinical samples from patients with chronic HBV infection. Overexpression of miR-3188 inhibited HBV transcription, whereas inhibition of miR-3188 expression promoted HBV transcription. Further investigation confirmed that miR-3188 inhibited HBV transcription by targeting Bcl-2. miR-3188 is a key miRNA that regulates HBV transcription by targeting the host protein Bcl-2. This observation provides insights into the regulation of cccDNA transcription and suggests new targets for anti-HBV treatment.
Asunto(s)
Hepatitis B Crónica , Hepatitis B , MicroARNs , Humanos , ADN Circular/genética , ADN Viral/genética , ADN Viral/metabolismo , Hepatitis B/genética , Virus de la Hepatitis B/genética , Hepatitis B Crónica/genética , MicroARNs/genética , MicroARNs/metabolismo , Transcripción Viral , Replicación Viral/genéticaRESUMEN
We have presented and demonstrated a fiber optic gas pressure sensor with ultra-high sensitivity based on Vernier effect. The sensor is composed of two integrated parallel Mach-Zehnder interferometers (MZIs) which are fabricated by fusion splicing a short section of dual side-hole fiber (DSHF) in between two short pieces of multimode fibers (MMFs). Femtosecond laser is applied for cutting off part of the MMF and drilling openings on one air hole of the DSHF to achieve magnified gas pressure measurement by Vernier effect. Experimental results show that the gas pressure sensitivity can be enhanced to about -60 nm/MPa in the range of 0-0.8 MPa. In addition, the structure possesses a low temperature cross-sensitivity of about 0.55 KPa/°C. This presented sensor has practically value in gas pressure detection, environmental monitoring and other industrial applications.
RESUMEN
Hydrogen gas sensing properties of Pt-WO3 films on spiral microstructured fiber Bragg grating (FBG) has been demonstrated. Pt-WO3 film was prepared by hydrothermal method. The spiral microsturctured FBG was fabricated using femtosecond laser. Spiral microstructure FBG hydrogen sensor can detect hydrogen concentration from 0.02% H2 to 4% H2 at room temperature, and the response time is shortened from a few minutes to 10~30 s. Double spiral microstructure at pitch 60 µm and sputtered with 2 µm Pt-WO3 film recorded hydrogen sensitivity of 522 pm/%(v/v) H2 responding to hydrogen gas in air. This translated to approximately 2~4 times higher than the unprocessed standard FBG. The humidity has little effect on the sensing property. The sensor has fast response time, good stability, large detection range and has the good prospect of practical application for hydrogen leak detection.
RESUMEN
To meet the requirements for low-frequency vibration monitoring, a new type of FBG (fiber Bragg grating) accelerometer with a bended spring plate is proposed. Two symmetrical bended spring plates are used as elastic elements, which drive the FBG to produce axial strains equal in magnitude but opposite in direction when exciting vibrations exist, leading to doubling the wavelength shift of the FBG. The mechanics model and a numerical method are presented in this paper, with which the influence of the structural parameters on the sensitivity and the eigenfrequency are discussed. The test results show that the sensitivity of the accelerometer is more than 1000 pm/g when the frequency is within the 0.7-20 Hz range.