Regulation of mouse embryonic stem cell self-renewal by a Yes-YAP-TEAD2 signaling pathway downstream of LIF

The cytoplasmic tyrosine kinase Yes has previously been shown to have an important role in maintaining mouse and human embryonic stem (ES) self-renewal through an unknown pathway downstream of leukemia inhibitory factor (LIF) and one or more factors in serum. Here, we show that TEAD2 and its transcriptional co-activator, the Yes-associated protein YAP, co-operate in a signaling pathway downstream of Yes. We show that YAP, TEAD2 and Yes are highly expressed in self-renewing ES cells, are activated by LIF and serum, and are downregulated when cells are induced to differentiate. We also demonstrate that kinase-active Yes binds and phosphorylates YAP, and activates YAP-TEAD2-dependent transcription. We found that TEAD2 associates directly with the Oct-3/4 promoter. Moreover, activation of the Yes pathway induced activity of the Oct-3/4 and Nanog promoters, whereas suppression of this pathway inhibited promoter activity. Nanog, in turn, suppressed TEAD2-dependent promoter activity, whereas siRNA-mediated knockdown of Nanog induced it, suggesting a negative regulatory feedback loop. Episomal supertransfection of cells with inhibitory TEAD2-EnR induced endodermal differentiation, which suggests that this pathway is necessary for ES cell maintenance

Efficiency of Virtualization

Darbā tiek apskatīta serveru virtualizācijas efektivitātes mērījumi starp dažādiem virtuāliem un fiziskiem operētājsistēmu risinājumiem. Darba mērķis ir pārliecināties par dažādu internetā pieejamu virtualizācijas aparatūru pārvaldnieku patiesajiem efektivitātes radītājiem, salīdzināt tos ar operētājsistēmu uzstādīšanu uz aparatūras neizmantojot pārvaldnieku. Mērījumu veikšanai tiks izmantoti dažādi nozarē atzīti testēšanas rīki, ar kuriem tiks mērīta procesoru veiktspēja, atmiņas ātrdarbība un cieto disku darbspēja. Salīdzināti virtualizācijas ieguvumi ar radītajām neērtībām un ierobežojumiem. Uzdevums: aprakstīt esošos pētījumus un salīdzinājumus, izstrādāt izvērstu virtualizācijas pārvaldnieku efektivitātes testēšanas mērījumu metodiku, veikt pētījumu salīdzinot to efektivitāti dažādiem virtualizācijas pārvaldniekiem. Rezultāti: izstrādāta efektivitātes mērījumu metodika, veikts pētījums, kur salīdzināti dažādi virtualizācijas risinājumi, rezultāti izklāstīti darbā. Virtualizējot sistēmas veiktspējas zudums ir 5 līdz 10 %. Atkarībā no izmantotā pārvaldnieka un uzstādītājām vies-operētājsistēmām. Atslēgvārdi: virtualizācija, virtuālā mašīna, efektivitāte, aparatūras pārvaldnieks;In this document has been described efficiency server virtualization, measurements between different virtual and physical operating system solutions. Aim of this work is to make clear about real virtualization hypervisors efficiency performances, comparing them with native OS installations. As measurements will be taken many free for use and known testing tools, for CPU, RAM and HDD. Compare advantages of virtualization and limits which we get of OS virtualization. Tasks: describe current research in this field, comparisons and results for any kind of hypervisors. Describe new and improved testing methodology of virtualization efficiency. Create a research for comparing few popular hypervisors. Results: Has been created methodology for efficiency testing of hypervisors. Developed research of performance comparison between hypervisors and native OS installation. Virtualization gives performance lost between 5 – 10 % depending of which hypervisor and guest OS used. Keywords: virtualization, virtual machine, efficiency, hypervisor

The Pisum sativum SAD short-chain dehydrogenase/reductase: quinone reduction, tissue distribution, and heterologous expression

The pea (Pisum sativum) tetrameric short-chain alcohol dehydrogenase-like protein (SAD) family consists of at least three highly similar members (SAD-A, -B, and -C). According to mRNA data, environmental stimuli induce SAD expression (Brosché and Strid (1999) Plant Physiol 121: 479-487). The aim of this study was to characterize the SAD proteins by examining their catalytic function, distribution in pea, and induction in different tissues. In enzyme activity assays using a range of potential substrates, the SAD-C enzyme was shown to reduce one- or two-ring membered quinones lacking long hydrophobic hydrocarbon tails. Immunological assays using a specific antiserum against the protein, demonstrated that different tissues and cell types were shown to contain small amounts of SAD protein that was predominantly located within epidermal or sub-epidermal cells and around vascular tissue. Particularly high local concentrations were observed in the protoderm of the seed cotyledonary axis. Two bow-shaped rows of cells in the ovary and the placental surface facing the ovule also exhibited considerable SAD staining. UV-B irradiation led to increased staining in epidermal and sub-epidermal cells of leaves and stems. The different localization patterns of SAD suggest functions in both development and in responses to environmental stimuli. Finally, the pea SAD-C promoter was shown to confer heterologous wound-induced expression in Arabidopsis thaliana, which confirmed that the inducibility of its expression is regulated at the transcriptional level