128 research outputs found
Pembuatan Alat Peraga Lemari Pendingin Sebagai Media Pembelajaran Mata Kuliah Teknik Pendingin Di Universitas Negeri Semarang
— Media pembelajaran merupakan segala fisik yang menyajikan pesan serta perangsang peserta didik untuk belajar, sehingga keberadaan media pembelajaran penting untuk membantu dalam proses belajar mengajar. Alat peraga adalah salah satu media pembelajaran, dengan memanfaatkan alat peraga proses pembelajaran akan dapat mempermudah dalam memahami materi yang dipelajari oleh mahasiswa, karena ditampilkan dalam bentuk nyata. Teknik Pendingin adalah salah satu mata kuliah yang ada pada Prodi Pendidikan Teknik Elektro. Permasalahannya apakah alat peraga lemari pendingin layak sebagai media pembelajaran pada mata kuliah Teknik Pendingin jurusan Teknik Elektro Universitas Negeri Semarang. Untuk itu perlu diadakan penelitian untuk mengetahui apakah alat peraga lemari pendingin ini layak untuk dignakan sebagai media pembelajaran. Data dikumpulkan dengan metode angket tertutup maupun terbuka. Alat peraga lemari pendingin ini diujicoba oleh dosen ahli materi teknik pendingin. Metode analisis yang digunakan adalah metode analisis statistik deskriptif. Menurut hasil penelitian dari responden secara keseluruhan, alat peraga lemari pendingin pada mata kuliah Teknik Pendingin ini layak digunakan sebagai media pembelajaran. Dosen ahli materi mengemukakan alat peraga ini layak dijadikan alat peraga setelah adanya revisi alat. Berdasarkan dari hasil penelitian dan pembahasan, dapat disimpulkan bahwa menurut mahasiswa media pembelajaran yang berupa alat peraga lemari pendingin pada mata kuliah Teknik Pendingin diwujudkan dengan menyusun prosedur kerja dengan langkah-langkah sebagai berikut: perencanaan alat peraga, penyediaan alat dan bahan, pembuatan alat peraga, validasi alat peraga, uji coba alat peraga, dan evaluasi. Dari hasil penelitian yang telah dilakukan kepada mahasiswa dengan beberapa aspek, alat peraga lemari pendingin ini termasuk dalam kategori layak, sehingga alat peraga ini dapat digunakan sebagai media pembelajaran. Namun masih terdapat kekurangan pada bahan penutup yang dugunakan seharusnya tidak menggunakan kaca agar tidah mudah pecah, dan jika menggunakan kaca suhu yang ada di dalam lemari pendingin masih dapat terpengaruh oleh suhu udara luar. Kata kunci— Media Pembelajaran, teknik pendingin, universitas negeri semarang, alat peraga, lemari pendingi
Monovalent and unpoised status of most genes in undifferentiated cell-enriched Drosophila testis
In undifferentiated Drosophila cells, differentiation-associated genes have monovalent, not bivalent histone modifications, in contrast to differentiation-associated genes in stem cells
A Novel Human Polycomb Binding Site Acts As a Functional Polycomb Response Element in Drosophila
Polycomb group (PcG) proteins are key chromatin regulators implicated in multiple processes including embryonic development, tissue homeostasis, genomic imprinting, X-chromosome inactivation, and germ cell differentiation. The PcG proteins recognize target genomic loci through cis DNA sequences known as Polycomb Response Elements (PREs), which are well characterized in Drosophila. However, mammalian PREs have been elusive until two groups reported putative mammalian PREs recently. Consistent with the existence of mammalian PREs, here we report the identification and characterization of a potential PRE from human T cells. The putative human PRE has enriched binding of PcG proteins, and such binding is dependent on a key PcG component SUZ12. We demonstrate that the putative human PRE carries both genetic and molecular features of Drosophila PRE in transgenic flies, implying that not only the trans PcG proteins but also certain features of the cis PREs are conserved between mammals and Drosophila
A novel genetic strategy reveals unexpected roles of the Swi–Snf–like chromatin-remodeling BAF complex in thymocyte development
We have developed a general strategy for creating littermates bearing either a tissue-specific point mutation or deletion in any target gene, and used the method to dissect the roles of Brg, the ATPase subunit of the chromatin-remodeling Brg-associated factor (BAF) complex, in early thymocyte development. We found that a point mutation that inactivates the Brg ATPase recapitulates multiple defects previously described for Brg deletion (Chi, T.H., M. Wan, P.P. Lee, K. Akashi, D. Metzger, P. Chambon, C.B. Wilson, and G.R. Crabtree. 2003. Immunity. 19:169–182). However, the point mutant helps reveal unexpected roles of Brg in CD25 repression and CD4 activation. Surprisingly, CD4 activation occurs independently of the Brg ATPase and is perhaps mediated by physical interactions between Brg and the CD4 locus. Our study thus suggests that the BAF complex harbors novel activities that can be necessary and even sufficient for stimulating transcription from an endogenous chromatin template in the absence of Brg-dependent remodeling of that template. We conclude that conditional point mutants, rarely used in mammalian genetics, can help uncover important gene functions undetectable or overlooked in deletion mutants
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Intent in Patent Infringement
In An Intentional Tort Theory of Patents , Professor Vishnubhakat makes two arguments. First, that liability for patent infringement should only be imposed upon defendants who intentionally make, use, or sell, patented inventions. And second, that if patent infringement includes such an intent requirement, it would no longer be a strict liability tort. This response agrees with the first thesis: patent infringement should require intentional conduct of a certain sort. However, the response disagrees with the second thesis: even if patent infringement requires such intent, liability would, in my view, still be “ strict.
c-Myc Is a Universal Amplifier of Expressed Genes in Lymphocytes and Embryonic Stem Cells
SummaryThe c-Myc HLH-bZIP protein has been implicated in physiological or pathological growth, proliferation, apoptosis, metabolism, and differentiation at the cellular, tissue, or organismal levels via regulation of numerous target genes. No principle yet unifies Myc action due partly to an incomplete inventory and functional accounting of Myc’s targets. To observe Myc target expression and function in a system where Myc is temporally and physiologically regulated, the transcriptomes and the genome-wide distributions of Myc, RNA polymerase II, and chromatin modifications were compared during lymphocyte activation and in ES cells as well. A remarkably simple rule emerged from this quantitative analysis: Myc is not an on-off specifier of gene activity, but is a nonlinear amplifier of expression, acting universally at active genes, except for immediate early genes that are strongly induced before Myc. This rule of Myc action explains the vast majority of Myc biology observed in literature
Histone modifications induced by MDV infection at early cytolytic and latency phases
Marek’s disease (MD) is a highly contagious, lymphomatous disease of chickens induced by a herpesvirus, Marek’s disease virus (MDV) that is the cause of major annual losses to the poultry industry. MD pathogenesis involves multiple stages including an early cytolytic phase and latency, and transitions between these stages are governed by several host and environmental factors. The success of vaccination strategies has led to the increased virulence of MDV and selective breeding of naturally resistant chickens is seen as a viable alternative. While multiple gene expression studies have been performed in resistant and susceptible populations, little is known about the epigenetic effects of infection. In this study, we investigated temporal chromatin signatures induced by MDV by analyzing early cytolytic and latent phases of infection in the bursa of Fabricius of MD-resistant and –susceptible birds. Major global variations in chromatin marks were observed at different stages of MD in the two lines. Differential H3K27me3 marks were associated with immune-related pathways, such as MAP kinase signaling, focal adhesion and neuroactive ligand receptor interaction, and suggested varying degrees of silencing in response to infection. Immune-related microRNAs, e.g. gga-miR-155 and gga-miR-10b, bore chromatin signatures, which suggested their contribution to MD-susceptibility. Finally, several members of the focal adhesion pathway, e.g. THBS4 and ITGA1, showed marked concordance between gene expression and chromatin marks indicating putative epigenetic regulation in response to MDV infection. Our comprehensive analysis of chromatin signatures, therefore, revealed further clues about the epigenetic effects of MDV infection although further studies are necessary to elucidate the functional implications of the observed variations in histone modifications.https://doi.org/10.1186/s12864-015-1492-
Dual functions of Tet1 in transcriptional regulation in mouse embryonic stem cells
Epigenetic modification of the mammalian genome by DNA methylation (5-methylcytosine) has a profound impact on chromatin structure, gene expression and maintenance of cellular identity1. The recent demonstration that members of the Ten-eleven translocation (Tet) family of proteins can convert 5-methylcytosine to 5-hydroxymethylcytosine raised the possibility that Tet proteins are capable of establishing a distinct epigenetic state2,3. We have recently demonstrated that Tet1 is specifically expressed in murine embryonic stem (ES) cells and is required for ES cell maintenance2. Using chromatin immunoprecipitation coupled with high-throughput DNA sequencing, here we show in mouse ES cells that Tet1 is preferentially bound to CpG-rich sequences at promoters of both transcriptionally active and Polycomb-repressed genes. Despite an increase in levels of DNA methylation at many Tet1-binding sites, Tet1 depletion does not lead to downregulation of all the Tet1 targets. Interestingly, although Tet1-mediated promoter hypomethylation is required for maintaining the expression of a group of transcriptionally active genes, it is also involved in repression of Polycomb-targeted developmental regulators. Tet1 contributes to silencing of this group of genes by facilitating recruitment of PRC2 to CpG-rich gene promoters. Thus, our study not only establishes a role for Tet1 in modulating DNA methylation levels at CpG-rich promoters, but also reveals a dual function of Tet1 in promoting transcription of pluripotency factors as well as participating in the repression of Polycomb-targeted developmental regulators
Global intron retention mediated gene regulation during CD4+ T cell activation.
T cell activation is a well-established model for studying cellular responses to exogenous stimulation. Using strand-specific RNA-seq, we observed that intron retention is prevalent in polyadenylated transcripts in resting CD4(+) T cells and is significantly reduced upon T cell activation. Several lines of evidence suggest that intron-retained transcripts are less stable than fully spliced transcripts. Strikingly, the decrease in intron retention (IR) levels correlate with the increase in steady-state mRNA levels. Further, the majority of the genes upregulated in activated T cells are accompanied by a significant reduction in IR. Of these 1583 genes, 185 genes are predominantly regulated at the IR level, and highly enriched in the proteasome pathway, which is essential for proper T cell proliferation and cytokine release. These observations were corroborated in both human and mouse CD4(+) T cells. Our study revealed a novel post-transcriptional regulatory mechanism that may potentially contribute to coordinated and/or quick cellular responses to extracellular stimuli such as an acute infection
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