The cutting edge of archaeal transcription

The archaeal RNA polymerase (RNAP) is a double-psi β-barrel enzyme closely related to eukaryotic RNAPII in terms of subunit composition and architecture, promoter elements and basal transcription factors required for the initiation and elongation phase of transcription. Understanding archaeal transcription is, therefore, key to delineate the universally conserved fundamental mechanisms of transcription as well as the evolution of the archaeo-eukaryotic transcription machineries. The dynamic interplay between RNAP subunits, transcription factors and nucleic acids dictates the activity of RNAP and ultimately gene expression. This review focusses on recent progress in our understanding of (i) the structure, function and molecular mechanisms of known and less characterized factors including Elf1 (Elongation factor 1), NusA (N-utilization substance A), TFS4, RIP and Eta, and (ii) their evolution and phylogenetic distribution across the expanding tree of Archaea.ATV, Acidianus two-tailed virus; CC, closed; CRISPR, Clustered Regularly Interspaced Short Palindromic Repeats; DPBB, double-psi β-barrel; ECs, elongation complexes; Elf1, Elongation factor 1; Eta, Euryarchaeal Termination Activity; IMR, initially melted region; Inr, initiator; KOW, Kyrpides–Ouzounis–Woese; NTD, N-terminal domain; NTS, non-template strand; NusA, N-utilization substance A; OB, oligonucleotide/oligosaccharide binding; OC, open complex; PIC, pre-initiation complex; RIP, RNAP inhibitory protein; RNAP, RNA polymerase; STIV, Sulfolobusturreted icosahedral virus; TBP, TATA-binding protein; TFB, transcription factor B; TFE, transcription factor E; WH, winged heli

Measurements of neutron and photon distributions by using an activation technique at the Pohang Neutron Facility

The Pohang Neutron Facility, which consists of an electron linear accelerator, a water-cooled Ta target with a water moderator, and a time-of-flight path with an 11-m length, was constructed to measure neutron total cross-sections in the neutron energy region from thermal to several hundreds of eV by using the time-of-flight method. In order to utilize this pulsed neutron facility based on an electron linac, we have to understand the characteristics of the radiation fields produced in this facility. We used the multiple-foil activation method to measure the neutron and the photon distributions produced by a water-cooled Ta target with and without the water moderator.11sciescopuskc

Measurement of isomeric cross-section ratios for the Sc-45(gamma,n)Sc-44m,Sc-g, Ti-nat (gamma,x)Sc-44m,Sc-g, Rh-103(gamma,4n)Rh-99m,Rh-g, and Fe-nat (gamma,x)Mn-52m,Mn-g reactions induced by 65-MeV bremsstrahlung

We measured isomeric cross-section ratios for the Sc-45(gamma,n)(SC)-S-44m,g, Ti-nat (gamma,x)(SC)-S-44m,g, Rh-103(gamma,4n)Rh-99m,Rh-g, and Fe-nat(gamma,x)Mn-52m,Mn-g reactions at the 65-MeV electron linac of the Po-hang Accelerator Laborator by using the activation method. Samples of natural Sc, Ti, Rh, and Fe metallic foils were irradiated in an uncollimated bremsstrahlung beam. The isomeric cross-section ratios were determined from the activity measurement with a high-purity germanium detector. The measured isomeric ratios were 0.21 +/- 0.03, 0.12 +/- 0.03, 1.43 +/- 0.20, and 0.28 +/- 0.04 for the Sc-45(gamma,n)Sc-44m,Sc-g, Ti-nat (gamma,x)Sc-44m,Sc-g, Rh-103(gamma,4n)Rh-99m,Rh-g, and Fe-nat(gamma,x)Mn-52m,Mn-g reactions, respectively. The present results for the Sc-45(gamma,n)Sc-44m,Sc-g and Fe-nat(gamma,x)Mn-52m,Mn-g reactions are in good agreement with other measurements. The present results for Ti-nat(gamma,x)(44m,g) Sc and Rh-103(gamma,4n)Rh-99m,Rh-g reactions are the first such measurements.11sciescopuskc

On symbolic RG factorization of quasi-birth-and-death processes

QBD process, RG factorization, Truncation methods, Retrial queues, 60J22, 60J27, 60K25,

Tips and Tricks to Probe the RNA-Degrading Activities of Hyperthermophilic Archaeal β-CASP Ribonucleases

International audienc