Architecture and ssDNA interaction of the Timeless-Tipin-RPA complex

The Timeless-Tipin (Tim-Tipin) complex, also referred to as the fork protection complex, is involved in coordination of DNA replication. Tim-Tipin is suggested to be recruited to replication forks via Replication Protein A (RPA) but details of the interaction are unknown. Here, using cryo-EM and biochemical methods, we characterized complex formation of Tim-Tipin, RPA and single-stranded DNA (ssDNA). Tim-Tipin and RPA form a 258 kDa complex with a 1:1:1 stoichiometry. The cryo-EM 3D reconstruction revealed a globular architecture of the Tim-Tipin-RPA complex with a ring-like and a U-shaped domain covered by a RPA lid. Interestingly, RPA in the complex adopts a horse shoe-like shape resembling its conformation in the presence of long ssDNA (>30 nucleotides). Furthermore, the recruitment of the TimTipin- RPA complex to ssDNA is modulated by the RPA conformation and requires RPA to be in the more compact 30 nt ssDNA binding mode. The dynamic formation and disruption of the Tim-Tipin-RPA-ssDNA complex implicates the RPA-based recruitment of Tim-Tipin to the replication fork

Cryo-electron microscopy in the fight against COVID-19—mechanism of virus entry

Cryogenic electron microscopy (cryo-EM) and electron tomography (cryo-ET) have become a critical tool for studying viral particles. Cryo-EM has enhanced our understanding of viral assembly and replication processes at a molecular resolution. Meanwhile, in situ cryo-ET has been used to investigate how viruses attach to and invade host cells. These advances have significantly contributed to our knowledge of viral biology. Particularly, prompt elucidations of structures of the SARS-CoV-2 spike protein and its variants have directly impacted the development of vaccines and therapeutic measures. This review discusses the progress made by cryo-EM based technologies in comprehending the severe acute respiratory syndrome coronavirus-2 (SARS-Cov-2), the virus responsible for the devastating global COVID-19 pandemic in 2020 with focus on the SARS-CoV-2 spike protein and the mechanisms of the virus entry and replication

Molecular clouds towards RCW 49 and Westerlund 2; Evidence for cluster formation triggered by cloud-cloud collision

We have made CO(J=2-1) observations towards the HII region RCW 49 and its ionizing source, the rich stellar cluster Westerlund 2 (hereafter Wd2), with the NANTEN2 sub-mm telescope. These observations have revealed that two molecular clouds in velocity ranges of -11 to +9 km/s and 11 to 21 km/s respectively, show remarkably good spatial correlations with the Spitzer IRAC mid-infrared image of RCW 49, as well a velocity structures indicative of localized expansion around the bright central regions and stellar cluster. This strongly argues that the two clouds are physically associated with RCW 49. We obtain a new kinematic distance estimate to RCW 49 and Wd2 of 5.4^{+ 1.1}_{- 1.4} kpc, based on the mean velocity and velocity spread of the associated gas. We argue that acceleration of the gas by stellar winds from Wd2 is insufficient to explain the entire observed velocity dispersion of the molecular gas, and suggest a scenario in which a collision between the two clouds ~4 Myrs ago may have triggered the formation of the stellar cluster.Comment: A version with higher resolution figures is available from http://www.a.phys.nagoya-u.ac.jp/~naoko/research/apjl2009/fur09_rev_highreso.pd

Classroom Activities to Include Children Who Need Special Consideration : Improving quality and ability to create classes that function as “the small society”

Building inclusive systems for elementary and special needs education is an important challenge. The present study examined the methods of teachers in regular elementary school classes that included children with educational support needs. First, we examined the approach of the teacher, including their intentions and aims. We then administered a questionnaire and analyzed a video recording of class meetings, school events and classroom activities. In addition, we created a map of the classroom group, examining the effectiveness of the teaching approach. The results indicated that by repeatedly undertaking classroom activity in line with the teacher’s intention and aims, the classroom group exhibited a form of self-government. These findings suggest that class group organization is an important factor for cultivating the quality and ability of the class to operate as a “small society”

Pilot VLBI Survey of SiO v=3 J=1--0 Maser Emission around Evolved Stars

In this Letter, we report detections of SiO v=3 J=1--0 maser emission in very long baseline interferometric (VLBI) observations towards 4 out of 12 long-period variable stars: WX Psc, R Leo, W Hya, and T Cep. The detections towards WX Psc and T Cep are new ones. We also present successful astrometric observations of SiO v=2 and v=3 J=1--0 maser emissions associated with two stars: WX Psc and W Hya and their position-reference continuum sources: J010746.0+131205 and J135146.8-291218 with the VLBI Exploration of Radio Astrometry (VERA). The relative coordinates of the position-reference continuum source and SiO v=3 maser spots were measured with respect to those of an SiO v=2 maser spot adopted as fringe-phase reference. Thus the faint continuum sources were inversely phase-referenced to the bright maser sources. It implies possible registration of multiple SiO maser line maps onto a common coordinate system with 10 microarcsecond-level accuracy.Comment: 5 Pages, 3 figures, Fig.3 and Tab. 2 were corrected; Publications of the Astronomical Society of Japan, Vol. 64, No. 6 issued on 2012 December 2

Studies on PTH-Amino Acids by High Voltage Filter Paper Electrophoresis

PTH-amino acids were synthesized by EDMAN\u27s method. PTH-amino acids were studied by high voltage filter paper electrophoresis under various conditions. The results of the electrophoresis were investigated by the ultraviolet ray. By the electrophoresis at 2000 V with pH 6 buffer, acid PTHamino acids and basic PTH-amino acids were distinctly detected, and PTHasparatic acid and PTH-asparagine, PTH-glutamic acid and PTH-glutamine were respectively confirmed. The neutral PTH-amino acids were detected by the electrophoresis with pH 4 or pH 2 or pH 1 buffer. The results of these experiments are discussed

A peculiar jet and arc of molecular gas toward the rich and young stellar cluster Westerlund 2 and a TeV gamma ray source

We have discovered remarkable jet- and arc-like molecular features toward the rich and young stellar cluster Westerlund2. The jet has a length of ~100 pc and a width of ~10 pc, while the arc shows a crescent shape with a radius of ~30 pc. These molecular features each have masses of ~10000 solar mass and show spatial correlations with the surrounding lower density HI gas. The jet also shows an intriguing positional alignment with the core of the TeV gamma ray source HESS J1023-575 and with the MeV/GeV gamma-ray source recently reported by the Fermi collaboration. We argue that the jet and arc are caused by an energetic event in Westerlund 2, presumably due to an anisotropic supernova explosion of one of the most massive member stars. While the origin of the TeV and GeV gamma-ray sources is uncertain, one may speculate that they are related to the same event via relativistic particle acceleration by strong shock waves produced at the explosion or by remnant objects such as a pulsar wind nebula or microquasar

A case of hepatocellular carcinoma with skin injury of the upper abdominal wall after transcatheter arterial chemoembolization: a case report

Introduction Transcatheter arterial chemoembolization has been widely used to treat advanced hepatocellular carcinoma that cannot be treated by local ablation therapies or surgical resection. The effectiveness of transcatheter arterial chemoembolization in prolonging survival has been well established, and approximately one third of newly discovered hepatocellular carcinoma patients were repeatedly treated by transcatheter arterial chemoembolization in Japan. Various kinds of complications have been reported, and many of which are general complications such as hepatic coma, jaundice, fever-up, ascites, and bile duct injury. The hepatic falciform artery is found frequently during postmortem anatomic dissection and the incidence of hepatic falciform artery is reported to be over 60%. Hepatic falciform artery is known to be the responsible artery for supraumbilical skin rash development after arterial chemo infusion therapy; however, skin complications after transcatheter arterial chemoembolization are rare. Case presentation A 70-year-old female with chronic hepatitis C infection was diagnosed as having hepatocellular carcinoma (S4, 20 mm in diameter). Transcatheter arterial chemoembolization was performed via the left hepatic artery, which was a feeding artery of the hepatocellular carcinoma. Two days after that, supraumbilical skin rash with local tenderness and redness appeared. Retrospective analysis revealed that occlusion of the hepatic falciform artery branching from the left hepatic artery with micromaterials caused the skin lesion. Conclusion We should keep in mind that anticancer drugs or embolic materials can flow into the HFA and may cause abdominal wall injury after transcatheter arterial chemoembolization

The Declined Activity in the Nucleus of NGC 1316

NGC 1316 (Fornax A) is a radio galaxy with prototypical double lobes, where the magnetic field intensity is accurately measured via the inverse-Compton technique. The radio-emitting electrons in the lobes are inferred to have a synchrotron life time of 0.1 Gyr. Considering the lobe energetics, we estimate the past nuclear X-ray luminosity of NGC 1316 to be at least 4 times 10^{34} W (4 times 10^{41} erg s^{-1}). Thus, the nucleus was rather active at least 0.1 Gyr ago. In contrast, we confirmed with ASCA and ROSAT that the nucleus of NGC 1316 is very faint in X-rays at present, with the 2--10 keV luminosity of any AGN-like hard component being < 2 times 10^{33} W (2 times 10^{40} erg s^{-1}) even assuming a nuclear obscuration up to 10^{28} m^{-2} (10^{24} cm^{-2}). This is at least an order of magnitude lower than the estimated past activity, indicating that the nucleus is presently very inactive. From these two results, we conclude that the nucleus of NGC 1316 has become dormant during the last 0.1 Gyr. This suggests the possible abundance of ``dormant'' quasars in nearby galaxies.Comment: 7 pages, 2 figures, to be published in the Astrophysical Journal Letter