Augmented B Lymphocyte Response to Antigen in the Absence of Antigen-Induced B Lymphocyte Signaling in an IgG-Transgenic Mouse Line

IgG-containing B cell antigen receptor (IgG-BCR), the BCR mostly expressed on memory B cells, contains a distinct signaling function from IgM-BCR or IgD-BCR expressed on naïve B cells. Because naïve B cells transgenic for IgG exhibit augmented response to antigens similar to memory B cells, the distinct signaling function of IgG-BCR appears to play a role in augmented antibody responses of memory B cells. However, how IgG-BCR signaling augments B cell responses is not yet well understood. Here we demonstrate that B cells from IgG-transgenic mice are anergic with defect in generation of BCR signaling upon BCR ligation. However, these IgG-transgenic B cells generate markedly augmented antibody response to a T cell-dependent antigen, probably due to hyper-responsiveness to a T cell-derived signal through CD40. Both BCR signaling defect and augmented response to CD40 ligation are partially restored in xid IgG-transgenic mice in which BCR signaling is down-modulated due to a loss-of-function mutation in the tyrosine kinase Btk crucial for BCR signaling. Thus, IgG-BCR induces augmented B cell responses in the absence of antigen-induced BCR signaling probably through high ligand-independent BCR signaling that may “idle” B cells to make them ready to respond to T cell help. This finding strongly suggests a crucial role of ligand-independent signaling in receptor function

The effect of our local motion on the Sandage-Loeb test of the cosmic expansion

Redshifts of an astronomical body measured at multiple epochs (e.g., separated by 10 years) are different due to the cosmic expansion. This so-called Sandage-Loeb test offers a direct measurement of the expansion rate of the Universe. However, acceleration in the motion of Solar System with respect to the cosmic microwave background also changes redshifts measured at multiple epochs. If not accounted for, it yields a biased cosmological inference. To address this, we calculate the acceleration of Solar System with respect to the Local Group of galaxies to quantify the change in the measured redshift due to local motion. Our study is motivated by the recent determination of the mass of Large Magellanic Cloud (LMC), which indicates a significant fraction of the Milky Way mass. We find that the acceleration towards the Galactic Center dominates, which gives a redshift change of 7 cm/s in 10 years, while the accelerations due to LMC and M31 cannot be ignored depending on lines of sight. We create all-sky maps of the expected change in redshift and the corresponding uncertainty, which can be used to correct for this effect.Comment: 6 pages, 3 figures. Accepted for publication in PAS

DNA replication-dependent binding of CTCF plays a critical role in adenovirus genome functions

The expression of adenovirus late genes is shown to require viral DNA replication, but its mechanism remains elusive. Here we found that knockdown of CTCF suppresses viral DNA replication as well as late, but not early, gene expression. Chromatin immunoprecipitation assays indicated that CTCF binds to viral chromatin depending on viral DNA replication. These findings depict CTCF as a critical regulator for adenovirus genome functions in late phases of infection

Gas Diffusivity and Thermal Properties of Compost-mixed Soils under Variable Water Saturation

Gas and heat transport through compostmixed landfill cover soils affect the emission of toxic gases and methane oxidization processes. In this study, we mixed soils with three different composts in the ratio of either 1:5 or 1:10 (compost:soil) to understand the effect of compost mixing for gas diffusivity and thermal properties. The gas diffusion coefficient (Dp), thermal conductivity ( ), and heat capacity (HC) were measured for soils, composts, and compost-mixed soils at different soil-water matric potentials ( ) starting from nearly saturated to = -10,000 cm H2O and dry conditions. Data were fitted to the Brooks-Corey soil-water retention curve model to estimate the bubbling pressure ( b). For all materials, Dp increased linearly with increased air content ( ), and the Penman-Call linear Dp( ) model with the model slope (C) and threshold soil-air content ( th) fitted the data well. The th values increased with increasing compost content, relating non-linearly to the Brooks-Corey b but highly linearly to the soil macroporosity. Analogous to the Dp( ) model, Penman-Call type linear ( ), and HC( ) models with slopes (C′ and C′′) and intercepts ( 0 and HC0, thermal conductivity and heat capacity at a volumetric water content of = 0) captured reasonably well the data measured from dry to wet conditions. The C′ for varied depending on the compost ratio and decreased with increasing compost ratio. The C′′ for HC, on the other hand, had less effect on the compost mix. The thermal properties under the dry condition, 0 and HC0, were well correlated to the volumetric solid content. The results from this study will be helpful towards designing compost-mixed landfill cover soils with optimal heat and gas transport characteristics

Metabolic Responses to Energy-Depleted Conditions

Dietary intervention is one of the most important approaches for the treatment of metabolic diseases such as diabetes mellitus. Fasting and caloric restriction have profound effects on systemic metabolism. The energy source-producing organs, such as the liver, and peripheral tissues rewire their metabolism to meet the energy demands of the whole body. Glycogenolysis, fatty acid oxidation, and ketone body production are characteristic metabolic changes that occur during fasting and caloric restriction. These metabolic changes are regulated by various signaling cascades including PPARα and FGF21. Moderate fasting and caloric restriction have also been implicated in extending the lifespan in a variety of organisms from nematodes to vertebrates. Intensive research has unveiled several regulatory mechanisms of longevity including metabolic regulators such as mTOR and sirtuins. The epigenome has been attracting attention as a mechanism underlying metabolic diseases and longevity. The epigenome is the concept that involves covalent modifications of DNA, histones, and RNA, which are mediated by the action of epigenetic enzymes. The activity of these enzymes is regulated by energy states, i.e. metabolites including ketone bodies and intermediates of various metabolic pathways. Thus, energy states are recorded in cells as an epigenetic memory, which may cause future onset of metabolic diseases and affect lifespan

RPT2/NCH1 subfamily of NPH3-like proteins is essential for the chloroplast accumulation response in land plants

葉緑体が光に集まる反応を制御する新たな因子の発見. 京都大学プレスリリース. 2016-08-30.In green plants, the blue light receptor kinase phototropin mediates various photomovements and developmental responses, such as phototropism, chloroplast photorelocation movements (accumulation and avoidance), stomatal opening, and leaf flattening, which facilitate photosynthesis. In Arabidopsis, two phototropins (phot1 and phot2) redundantly mediate these responses. Two phototropin-interacting proteins, NONPHOTOTROPIC HYPOCOTYL 3 (NPH3) and ROOT PHOTOTROPISM 2 (RPT2), which belong to the NPH3/RPT2-like (NRL) family of BTB (broad complex, tramtrack, and bric à brac) domain proteins, mediate phototropism and leaf flattening. However, the roles of NRL proteins in chloroplast photorelocation movement remain to be determined. Here, we show that another phototropin-interacting NRL protein, NRL PROTEIN FOR CHLOROPLAST MOVEMENT 1 (NCH1), and RPT2 redundantly mediate the chloroplast accumulation response but not the avoidance response. NPH3, RPT2, and NCH1 are not involved in the chloroplast avoidance response or stomatal opening. In the liverwort Marchantia polymorpha, the NCH1 ortholog, MpNCH1, is essential for the chloroplast accumulation response but not the avoidance response, indicating that the regulation of the phototropin-mediated chloroplast accumulation response by RPT2/NCH1 is conserved in land plants. Thus, the NRL protein combination could determine the specificity of diverse phototropin-mediated responses

FDM simulation of long-period ground motions around Oita Prefecture, Japan, using a land-ocean unified 3D structure model

Oita prefecture is located in northeastern part of Kyushu Island which is characterized by active subduction of the Philippine Sea plate (PHS) beneath the Eurasian plate and several active volcanoes along with the volcanic front. Oita area has frequently been damaged by large earthquakes and tsunamis since ancient times. From the point of view of disaster prevention, it is important to investigate the feasibility of strong ground motion prediction using realistic structural models. In this paper we use a land-ocean unified 3D (three-dimensional) structure model around Oita prefecture, which includes land and sea-floor topography and a seawater layer as well as subsurface structures of the arc side and the PHS slab to conduct the FDM (finite-difference method) simulations of strong ground motion in land and ocean areas for the 2015 Southern Oita, Japan, earthquake (MJMA5.7) whose hypocenter is located in the PHS slab. The simulated long-period (2–20 s) ground motions reproducing observed records demonstrate substantial contributions of thick low-velocity sediment layers in and around Beppu Bay and Oita basin to development of the motions. We also examine the topographic effects on the seismic motion by analyzing the simulation results to show the strong enhancement of the later phases