As a key material for phosphor-converted light-emitting diodes (pc-LEDs) applications, broadband near-infrared (NIR) phosphors currently face poor thermal stability issues. In this work, we synthesized a broadband near-infrared phosphor YGa(BO): Cr (YGBO: Cr) with a high thermal stability. The YGBO: Cr sample exhibits a broadband near-infrared emission centered at 770 nm with a full width at half-maximum (fwhm) of 2130 cm under blue light excitation.
View Article and Find Full Text PDFAt present, most fluorescent materials that can be used for optical temperature measurement exhibit poor thermochromic performance, which limits their applications. In this study, the phosphor BaIn(PO):Er/Yb was synthesized with a high doping concentration of Yb, and it emitted composition- and temperature-induced wide color gamut up-conversion luminescence from red to green. Four modes of fluorescence thermometry can be realized in the temperature range of 303-603 K, which is based on the ratio of fluorescence intensity between thermally coupled energy levels and non-thermally coupled energy levels, color coordinate shift, and fluorescence decay lifetime, respectively.
View Article and Find Full Text PDFCRISPR-Cas9 systems provide a platform for high efficiency genome editing that are enabling innovative applications of mammalian cell engineering. However, the delivery of Cas9 and synthesis of guide RNA (gRNA) remain as steps that can limit overall efficiency and ease of use. Here we describe methods for rapid synthesis of gRNA and for delivery of Cas9 protein/gRNA ribonucleoprotein complexes (Cas9 RNPs) into a variety of mammalian cells through liposome-mediated transfection or electroporation.
View Article and Find Full Text PDFSaccharomyces cerevisiae Esc2p is a member of a conserved family of proteins that contain small ubiquitin-like modifier (SUMO)-like domains. It has been implicated in transcriptional silencing and shown to interact with the silencing protein Sir2p in a two-hybrid analysis. However, little is known about how Esc2p regulates the structure of silent chromatin.
View Article and Find Full Text PDFSaccharomyces cerevisiae linker histone Hho1p is not essential for cell viability, and very little is known about its function in vivo. We show that deletion of HHO1 (hho1Delta) suppresses the defect in transcriptional silencing caused by a mutation in the globular domain of histone H4. hho1Delta also suppresses the reduction in HML silencing by the deletion of SIR1 that is involved in the establishment of silent chromatin at HML.
View Article and Find Full Text PDFNucleic Acids Res
September 2008
Sas2p is a histone acetyltransferase implicated in the regulation of transcriptional silencing, and ORC is the six-subunit origin recognition complex involved in the initiation of DNA replication and the establishment of transcriptionally silent chromatin by silencers in yeast. We show here that SAS2 deletion (sas2Delta) exacerbates the temperature sensitivity of the ORC mutants orc2-1 and orc5-1. Moreover, sas2Delta and orc2-1 have a synthetic effect on cell cycle progression through S phase and initiation of DNA replication.
View Article and Find Full Text PDFIn Saccharomyces cerevisiae, silencers flanking the HML and HMR loci consist of various combinations of binding sites for Abf1p, Rap1p, and the origin recognition complex (ORC) that serve to recruit the Sir silencing complex, thereby initiating the establishment of transcriptionally silent chromatin. There have been seemingly conflicting reports concerning whether silencers function in an orientation-dependent or -independent manner, and what determines the directionality of a silencer has not been explored. We demonstrate that chromatin plays a key role in determining the potency and directionality of silencers.
View Article and Find Full Text PDFIn Saccharomyces cerevisiae, silencers flanking the HML and HMR loci initiate the establishment of transcriptional silencing. We demonstrate that the activity of a silencer pertaining to its potency and directionality is dependent on its genomic position. The context of the HML-E silencer is more permissive to silencer function than that of HML-I or HMR-E, despite that HML-E and HML-I are only 3.
View Article and Find Full Text PDFEukaryotic genomes contain euchromatic regions, which are transcriptionally active, and heterochromatic regions, which are repressed. These domains are separated by "barrier elements": DNA sequences that protect euchromatic regions from encroachment by neighboring heterochromatin. To identify proteins that play a role in the function of barrier elements we have carried out a screen in S.
View Article and Find Full Text PDFTranscriptionally silent chromatin in Saccharomyces cerevisiae is associated with histone hypoacetylation and is formed through the action of the Sir histone deacetylase complex. A histone acetyltransferase (HAT) targeted near silent chromatin can overcome silencing at a distance by increasing histone acetylation in a sizable region. However, how a tethered HAT acetylates distant nucleosomes has not been resolved.
View Article and Find Full Text PDFThe eukaryotic genome is divided into chromosomal domains of distinct gene activities. Transcriptionally silent chromatin tends to encroach upon active chromatin. Barrier elements that can block the spread of silent chromatin have been documented, but the mechanisms of their function are not resolved.
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