Functional analysis of plant immune regulator OsPti1a in rice

　An understanding of plant immune systems is important for crop breeding with enhanced disease resistance against pathogen infection. Previous studies reveal that plant has evolved two types of defense mechanisms, which are called “basal resistance” and “R‒gene mediated resistance”, for protecting thewrselves from pathogen attack. Recent studies suggest that both defense systems use a common pathway to activate defense responses, however, the downstream components in both pathways are still obscure. 　OsPto-interacting protein 1a (OsPti1a), which is a functional ortholog of tomato Pti1, negatively regulates both basal resistance and R‒gene mediated resistance in rice. ospti1a mutant shows lesion formation and accompanying defense responses without pathogen infection. OsPti1a is phosphorylated by upstream kinase oxidative signal inducible1 (OsOxi1) and the phosphorylation of OsPti1a has an important role in activating basal resistance against pathogen infection. Additionally, OsOxi1 is phosphorylated by upstream kinase 3‒phosphoinotiside-dependent protein kinase 1 (OsPdk1). OsPdk1 has an important role for activating basal resistance against compatible pathogen infection. Therefore, OsPdk1-OsOxi1-OsPti1a phosphorylation cascade regulates proper activation of basal resistance in rice. 　Interestingly, OsPti1a localizes at plasma membrane, and cellular localization of OsPti1a has an important function in suppvessing lesion formation. Especially, N‒terminal amino acid sequences of OsPti1a have a post-translational modification for binding to plasma membrane. Further, OsPti1a forms complexes with potentially plant immune related proteins at plasma membrane, suggesting that plasma membrane localized OsPti1a probably regulates plant immune complex through its phosphorylation during pathogen infection

Effects of Minor Mergers on Coalescence of a Supermassive Black Hole Binary

We study the possibility that minor mergers resolve the loss cone depletion problem, which is the difficulty occured in the coalescence process of the supermassive black hole (SMBH) binary, by performing numerical simulations with a highly accurate $N$-body code. We show that the minor merger of a dwarf galaxy disturbs stellar orbits in the galactic central region of the host galaxy where the loss cone depletion is already caused by the SMBH binary. The disturbed stars are supplied into the loss cone. Stars of the dwarf galaxy are also supplied into the loss cone. The gravitational interactions between the SMBH binary and these stars become very effective. The gravitational interaction decreases the binding energy of the SMBH binary effectively. As a result, the shrink of the separation of the SMBH binary is accelerated. Our numerical results strongly suggest that the minor mergers are one of the important processes to reduce the coalescence time of the SMBH binary much less than the Hubble time.Comment: 6 pages, 16 figures. accepted for publication in PAS

Practical Preparation of Epilactose Produced with Cellobiose 2-Epimerase from Ruminococcus albus NE1

A practical purification method for a non-digestible disaccharide, epilactose (4-O-beta-galactosyl-D-mannose), was established. Epilactose was synthesized from lactose with cellobiose 2-epimerase and purified by the following procedure: (i) removal of lactose by crystallization, (ii) hydrolysis of lactose by beta-galactosidase, (iii) digestion of monosaccharides by yeast, and (iv) column chromatography with Na-form cation exchange resin. Epilactose of 91.1% purity was recovered at 42.5% yield

Replacement and late formation of atmospheric N2 on undifferentiated Titan by impacts

Saturn’s moon, Titan, has remarkable surface features—a massive N2 atmosphere and hydrological cycle of CH4—that are often compared with that of Earth^1^. However, the origin and evolution of Titan’s atmosphere remains largely unknown. The proposed formation mechanisms for Titan’s N2 require a prolonged, warm proto-atmosphere during accretion^2-4^. These mechanisms accordingly would not have worked efficiently if Titan stayed cold, as indicated by the incompletely differentiated interior observed by Cassini^5^. Because formation of a massive secondary atmosphere on a planetary body would associate with a major differentiation of its sold body during accretion^6–8^, the presence of such an atmosphere on undifferentiated cold Titan poses a serious dilemma on our view of how planetary bodies develop atmospheres. Here we propose a new mechanism for the post-accretion formation of Titan’s N2 to resolve this problem: conversion and replenishment of N2 from NH3 contained in Titan by impacts during the late heavy bombardment (LHB)^9^. Our results show that Titan, regardless of its thermal history, would acquire sufficient N2 to account for the current atmosphere during the LHB and that most of the pre-LHB atmosphere would have replaced by impact-induced N2. This is the first scenario capable of generating a N2-rich and nearly primordial Ar-free atmosphere on undifferentiated cold Titan. We also suggest that Titan’s N2 was delivered from a different source in the solar nebula compared with Earth and that the origins of N2 on Titan and Triton are fundamentally different with that of N2 on Pluto

Lansoprazole Novel Effector Sites Revealed by Autoradiography: Relation to Helicobacter pylori, Colon, Esophagus and Others

Lansoprazole uptake sites by two kinds of autoradiographic procedures were compared with recent literature. The uptake sites have been seen in the Helicobacter pylori, colonic epithelial cells, inflammatory cells, peripheral autonomic nerves and enterochromaffinlike cells as well as gastric parietal cells. Each uptake sites corresponded to the reported localization of P-type ATPase or acidic compartment

Mass Supply to Galactic Center due to Nested Bars in the Galaxy

We investigate rapid mass supply process by nested bars in the Galaxy by numerical simulation. We simulate gas flow in the whole galaxy disk with nested bars, which are the outer bar and the inner bar, especially with highly spatial resolution in the galactic central region. We assume two cases of inner bar size which are a smaller one and a larger one than the radius of the 200 pc gas ring which is corresponds to the Central Molecular Zone. From our numerical results, in the large size bar cases, the inner bars with large elongation induce sufficient mass inflow and destroy the 200 pc gas ring. On the other hand, in the small size bar cases, the inner bars with large elongation induce large mass inflow and do not destroy the 200 pc gas ring. This mass inflow is caused by straight shocks excited by the inner bar. In this case, nuclear gas disks of ~ 15 pc radius are formed. The nuclear gas disks are self-gravitationally unstable and we expect formation of compact star clusters under strong tidal force in the nuclear gas disks. We discuss evolution of the nuclear gas disk.Comment: 36 pages, 11 figures. Submitted to Ap

Quorum-dependent expression of rsmX and rsmY, small non-coding RNAs, in Pseudomonas syringae

Pseudomonas syringae pathovars are known to produce N-acyl-homoserine lactones (AHL) as quorum-sensing molecules. However, many isolates, including P. syringae pv. tomato DC3000 (PtoDC3000), do not produce them. In P. syringae, psyI, which encodes an AHL synthase, and psyR, which encodes the transcription factor PsyR required for activation of psyI, are convergently transcribed. In P. amygdali pv. tabaci 6605 (Pta6605), there is one nucleotide between the stop codons of both psyI and psyR. However, the canonical stop codon for psyI in PtoDC3000 was converted to the cysteine codon by one nucleotide deletion, and 23 additional amino acids extended it to a C-terminal end. This resulted in overlapping of the open reading frame (ORF) for psyI and psyR. On the other hand, stop codons in the psyR ORF of P. syringae 7 isolates, including pv. phaseolicola and pv. glycinea, were found. These results indicate that many pathovars of P. syringae have genetically lost AHL production ability by the mutation of their responsible genes. To examine whether PtoDC3000 modulates the gene expression profile in a population-dependent manner, we carried out microarray analysis using RNAs prepared from low- and high-density cells. We found the expressions of rsmX and rsmY remarkably activated in high-density cells. The activated expressions of rsmX and rsmY were confirmed by Northern blot hybridization, but these expressions were abolished in a ΔgacA mutant of Pta6605. These results indicate that regardless of the ability to produce AHL, P. syringae regulates expression of the small noncoding RNAs rsmX/Y by currently unknown quorum-sensing molecules