The 2'-5' RNA Ligase of Escherichia coli: Purification, Cloning, and Genomic Disruption

An RNA ligase previously detected in extracts of Escherichia coli is capable of joining Saccharomyces cerevisiae tRNA splicing intermediates in the absence of ATP to form a 2-5 phosphodiester linkage (Greer, C., Javor, B., and Abelson, J. (1983) Cell 33, 899-906). This enzyme specifically ligates tRNA half-molecules containing nucleoside base modifications and shows a preference among different tRNA species. In order to investigate the function of this enzyme in RNA metabolism, the ligase was purified to homogeneity from E. coli lysate utilizing chromatographic techniques and separation of proteins by SDS-polyacrylamide gel electrophoresis. A single polypeptide of approximately 20 kilodaltons exhibited RNA ligase activity. The amino terminus of this protein was sequenced, and the open reading frame (ORF) encoding it was identified by a data base search. This ORF, which encodes a novel protein with a predicted molecular mass of 19.9 kDa, was amplified from E. coli genomic DNA and cloned. ORFs coding for highly similar proteins were detected in Methanococcus jannaschii and Bacillus stearothermophilus. The chromosomal gene encoding RNA ligase in E. coli was disrupted, abolishing ligase activity in cell lysates. Cells lacking ligase activity grew normally under laboratory conditions. However, moderate overexpression of the ligase protein led to slower growth rates and a temperature-sensitive phenotype in both wild-type and RNA ligase knockout strains. The RNA ligase reaction was studied in vitro using purified enzyme and was found to be reversible, indicating that this enzyme may perform cleavage or ligation in vivo

On the Economics of Internet Peering

We discuss economic rationales behind peering decisions in the Internet. In We discuss economic rationales behind peering decisions in the Internet. In the first part of the paper we analyze the decision about a bilateral peering agreement between two commercial Internet service providers (ISPs) who are in Cournot competition. In the second part we discuss multilateral peer-ing between commercial ISPs and an academic research network (ARN). The latter is organized as club of academics who share the cost of their net-work. It is discussed whether peering threatens the existence of the ARN and under what circumstances a commercial ISP would want to use strate-gic pricing to win all ARN-members as customers.Internet Economics, Interconnection Agreements

Die Fallstricke einer intentionalistischen Engführung der Geschichtsdeutung

In this commentary I criticise Doris Gerber's intentionalistic reading of history. While an intentionalistic philosophy of history has some plausibility, a *purely* intentionalistic view is often irreconcilable with the most elementary common sense. For example, that history ought to be considered exclusively as the history of human action and not of things that simply happen to humans as well - like the outbreak of the volcano Vesuv in the year 79 which lead to the destructions of Pompeii. Or that historical value judgments should always be judgments about the reasons for human action, which raises the questions if and how the unintended consequences of human action are to be judged

Current Accuracy of Augmented Reality Neuronavigation Systems: Systematic Review and Meta-Analysis

BACKGROUND Augmented reality neuronavigation (ARN) systems can overlay three-dimensional anatomy and pathology without the need for a two-dimensional external monitor. Accuracy is crucial for their clinical applicability. We performed a systematic review regarding the reported accuracy of ARN systems and compared them with the accuracy of conventional infrared neuronavigation (CIN). OBJECTIVE Explore the current navigation accuracy of ARN systems and compare them with CIN. METHODS Pubmed and Embase were searched for ARN and CIN systems. For ARN: type of system, method of patient-to-image registration, accuracy method and accuracy of the system was noted. For CIN: navigation accuracy, expressed as target registration error (TRE), was noted. A meta-analysis was performed comparing the TRE of ARN and CIN systems. RESULTS 35 studies were included, 12 for ARN and 23 for CIN. ARN systems were divided into head-mounted display and heads-up display. In ARN, four methods were encountered for patient-to-image registration, of which point-pair matching was the one most frequently used. Five methods for assessing accuracy were described. 94 TRE measurements of ARN systems were compared with 9058 TRE measurements of CIN systems. Mean TRE was 2.5 mm (CI 95% 0.7 - 4.4) for ARN systems and 2.6 mm (CI 95% 2.1 - 3.1) for CIN systems. CONCLUSIONS In ARN, there seems to be lack of agreement regarding the best method to assess accuracy. Nevertheless, ARN systems seem able to achieve an accuracy comparable with CIN systems. Future studies should be prospective and compare TREs which should be measured in a standardized fashion

UAV sebagai Infrastruktur Jaringan Seluler pada Keadaan Darurat

Pertukaran informasi di suatu daerah bencana harus dapat bergerak lebih cepat untuk membantu proses pemulihan pasca bencana sehingga kebutuhan bagi para korban dapat dipenuhi secara efisien. Pada jalur komunikasi seluler terdapat limitasi dikarenakan dapat dipengaruhi dengan kondisi bencana seperti pemadaman listrik hingga kerusakan pada base station akibat bencana. Sehingga dibutuhkan suatu teknologi yang dapat memungkinkan adanya telekomunikasi efektif saat pasca bencana. Pada penelitian ini dirancang dua model arsitektur aerial relay node (ARN) berbasis Unmanned Aerial Vehicle (UAV). ARN digunakan untuk menyediakan jalur komunikasi pada suatu daerah bencana dengan cara meneruskan data yang diterima dari User Equipments (UEs) yang dijangkau dan diteruskan ke macro base station (MBS) terdekat dan sebaliknya. Model pertama menggunakan relay node berjenis amplify-and-forward (AF) dimana menggunakan jaringan generasi ke-4 4G LTE/LTEA pada jaringan fronthaul (ARN-MBS) dan jaringan akses (ARN-UEs). Model tersebut secara umum bekerja sebagai suatu repeater atau amplifier. Sementara untuk model kedua, ARN dengan jenis decode-and-forward (DF) bekerja sebagai seperti suatu mobile hotspot dimana digunakan 4G LTE/LTEA pada jaringan fronthaul dan wifi 802.11n pada jaringan aksesnya. Pada penelitian ini, Desa Sumbermujur dengan area seluas 16 km2 dijadikan sebagai objek penelitian. Terdapat tiga parameter utama yang akan diteliti pada kedua model tersebut yakni ketinggian optimum ARN, jarak maksimum antara ARN dengan MBS, dan yang terakhir adalah jangkauan maksimum dari ARN. Hasil dari penelitian ini didapatkan bahwa ketinggian optimum dari ARN-AF dan ARN-DF berada pada ketinggian maksimum yaitu 150 meter. Selanjutnya untuk jarak maksimum antara ARN-AF dengan MBS adalah sejauh 11 kilometer dan 8,5 kilometer untuk ARN-DF dengan MBS. Dari segi jangkauan, ARN-AF mampu menjangkau 100% objek penelitian yakni Desa Sumbermujur dengan area seluas 16 km2 sementara ARN-DF hanya mampu menjangkau 3,349% area dari Desa Sumbermujur

Multiple Worship Services and Church Growth

Approximately half of the 355,000 Protestant churches in the U.S. and Canada should consider adding a new style worship service to their weekly schedule of activities, regardless of the number of services they present offer. Of the churches that do begin a new service, eight out of ten will experience a measurable increase in 1) total worship attendance, 2) total giving, and 3) number of Christian conversions

Bye Bye Rocking Chair

Senior adults in most churches have more available time … give more financially (one study indicated seven times more) than younger members … have years of valuable experience working in the church … don’t go “church shopping,” nor do they often move their residence … their work quality is high, and church loyalty solid

Bye Bye Rocking Chair

Senior adults in most churches have more available time … give more financially (one study indicated seven times more) than younger members … have years of valuable experience working in the church … don’t go “church shopping,” nor do they often move their residence … their work quality is high, and church loyalty solid

Analysis of TRIP expression in different types of skin tumor

TRAF-interacting protein (TRIP) is a ubiquitously expressed nucleolar E3 ubiquitin ligase. Ubiquitination of proteins is a post-translational modification, which decides on the cellular fate of the protein. TRIP in vivo substrate has not been yet identified. However, TRIP has been shown to play an important role in cellular proliferation, especially in keratinocytes. TRIP was found to be up-regulated in basal cell carcinoma (BCC) at the mRNA level. This prompted us to elucidate its role in skin proliferative diseases such as cancer by analyzing its expression in BCCs at protein level and in squamous cell carcinoma (SCC) at mRNA and protein level. To that purpose, we performed a real-time PCR (qPCR) analysis followed by an immunohistochemistry (IHC) on formalin-fixed, paraffin-embedded (FFPE) biopsies. The real-time PCR was performed on 12 RNA samples of which 6 were extracted from SCC biopsies and 6 from normal human skin. The results were statistically insignificant. Further analyses are needed on new RNA samples. The IHC assay was performed on 20 biopsies from BCCs, 21 biopsies from SCCs and on 5 tissues from normal human skin. The results obtained showed an extensive expression of TRIP in keratinocytes nuclei. Due to various limitations related to the technique and to doubts about preservation of the antigens in the tissues from normal human skin, we could not highlight a clear difference in TRIP expression between the different tissues. In conclusion, further analyses are needed on new RNA samples (qPCR) and on better preserved FFPE tissues from normal skin (IHC) to assess TRIP relative expression in BCCs and SCCs versus normal human skin