Self-assembled InAs quantum wires(QWRs)are fabricated on an InP substrate by solid-source molecular beam epitaxy(SSMBE).Photoluminescence(PL)spectra are investigated in these nanostructures as a function of temperatur...Self-assembled InAs quantum wires(QWRs)are fabricated on an InP substrate by solid-source molecular beam epitaxy(SSMBE).Photoluminescence(PL)spectra are investigated in these nanostructures as a function of temperature.An anomalous enhancement of PL intensity and a temperature insensitive PL emission are observed from InAs nanostructures grown on InP substrates using InAlGaAs as the matrix layer and the origin of this phenomenon is discussed.We attribute the anomalous temperature dependence of photoluminescence to the formation of Al-rich and In-rich region in the InAlGaAs buffer layer and the cap layer.展开更多
Lipopolysaccharide binding protein(LBP) is a key factor in the recognition of lipopolysaccharide(LPS) and the initiation of immune response, thus regulating the body’s resistance to pathogenic infection. To investiga...Lipopolysaccharide binding protein(LBP) is a key factor in the recognition of lipopolysaccharide(LPS) and the initiation of immune response, thus regulating the body’s resistance to pathogenic infection. To investigate the tissue-specific expression characteristics of the LBP gene and its transcriptional regulation in pigs, we detected LBP expression in different tissues of 35-day-old Meishan weaned piglets, determined LBP core promoter region using bioinformatics prediction combined with dual luciferase activity assay, and finally detected methylation levels by pyrosequencing. The results showed that LBP expression in the liver tissue was significantly higher(P<0.01) than that in other tissues, followed by the intestinal tissues. The core promoter region of LBP was located at -500-(-206) bp(chr.17: g.46837534-g.46837828), containing three Cp G sites(Cp G1, Cp G2 and Cp G3). Of the three Cp G sites, Cp G2 and Cp G3 were variously methylated(P<0.01) in different tissues. Moreover, LBP m RNA levels were negatively correlated(P<0.01) with methylation levels of the Cp G2 and Cp G3 sites in the YY1 transcription factor binding sequence. It is speculated that the methylation of Cp G2 and Cp G3 sites might inhibit YY1 binding to the promoter sequences, thereby regulating the tissue-specific expression of LBP. This study demonstrated the distinct patterns of LBP expression and promoter methylation in the tissues of Meishan pigs and indicated the potential roles of DNA methylation in regulating LBP expression, which may contribute to further investigations on pig LBP gene expression and function.展开更多
基金Supported by the National Natural Science Foundation of China under Grant No 60990315the National Basic ResearchProgram of China under Grant No 2006CB604904.
文摘Self-assembled InAs quantum wires(QWRs)are fabricated on an InP substrate by solid-source molecular beam epitaxy(SSMBE).Photoluminescence(PL)spectra are investigated in these nanostructures as a function of temperature.An anomalous enhancement of PL intensity and a temperature insensitive PL emission are observed from InAs nanostructures grown on InP substrates using InAlGaAs as the matrix layer and the origin of this phenomenon is discussed.We attribute the anomalous temperature dependence of photoluminescence to the formation of Al-rich and In-rich region in the InAlGaAs buffer layer and the cap layer.
基金supported by the grants from the College Students’Innovation and Entrepreneurship Training Program of Jiangsu Province,China(201811117014Z)the Priority Academic Program Development of Jiangsu Higher Education Institutions,China。
文摘Lipopolysaccharide binding protein(LBP) is a key factor in the recognition of lipopolysaccharide(LPS) and the initiation of immune response, thus regulating the body’s resistance to pathogenic infection. To investigate the tissue-specific expression characteristics of the LBP gene and its transcriptional regulation in pigs, we detected LBP expression in different tissues of 35-day-old Meishan weaned piglets, determined LBP core promoter region using bioinformatics prediction combined with dual luciferase activity assay, and finally detected methylation levels by pyrosequencing. The results showed that LBP expression in the liver tissue was significantly higher(P<0.01) than that in other tissues, followed by the intestinal tissues. The core promoter region of LBP was located at -500-(-206) bp(chr.17: g.46837534-g.46837828), containing three Cp G sites(Cp G1, Cp G2 and Cp G3). Of the three Cp G sites, Cp G2 and Cp G3 were variously methylated(P<0.01) in different tissues. Moreover, LBP m RNA levels were negatively correlated(P<0.01) with methylation levels of the Cp G2 and Cp G3 sites in the YY1 transcription factor binding sequence. It is speculated that the methylation of Cp G2 and Cp G3 sites might inhibit YY1 binding to the promoter sequences, thereby regulating the tissue-specific expression of LBP. This study demonstrated the distinct patterns of LBP expression and promoter methylation in the tissues of Meishan pigs and indicated the potential roles of DNA methylation in regulating LBP expression, which may contribute to further investigations on pig LBP gene expression and function.
