Nebulin and N-WASP cooperate to cause IGF-1-induced sarcomeric actin filament formation

Insulin-like growth factor 1 (IGF-1) induces skeletal muscle maturation and enlargement (hypertrophy). These responses require protein synthesis and myofibril formation (myofibrillogenesis). However, the signaling mechanisms of myofibrillogenesis remain obscure. We found that IGF-1-induced phosphatidylinositol 3-kinase-Akt signaling formed a complex of nebulin and N-WASP at the Z bands of myofibrils by interfering with glycogen synthase kinase-3β in mice. Although N-WASP is known to be an activator of the Arp2/3 complex to form branched actin filaments, the nebulin-N-WASP complex caused actin nucleation for unbranched actin filament formation from the Z bands without the Arp2/3 complex. Furthermore, N-WASP was required for IGF-1-induced muscle hypertrophy. These findings present the mechanisms of IGF-1-induced actin filament formation in myofibrillogenesis required for muscle maturation and hypertrophy and a mechanism of actin nucleation.     

Expression of monocarboxylate transporter 1 (MCT1) in the dog intestine

In this study, the expression and distribution of monocarboxyolate transporter 1 (MCT1) along the intestines (duodenum, jejunum, ileum, cecum, colon and rectum) of dogs were investigated at both the mRNA and protein levels. The expression of MCT1 protein and its distribution were confirmed by Western blotting and immunohistochemical staining using the antibody for MCT1. We identified mRNA coding for MCT1 and a 43-kDa band of MCT1 protein in all regions from the duodenum to the rectum. Immunoreactive staining for MCT1 was also observed in epithelial cells throughout the intestines. MCT1 immunoreactivity was greater in the large intestine than in the small intestine. MCT1 protein was predominantly expressed on the basolateral membranes along intestinal epithelial cells, suggesting that MCT1 may play an important role in lactate efflux and transport of short-chain fatty acids (SCFAs) to the bloodstream across the basolateral membranes of the dog intestine.     

Mycobacterium ulcerans infection in an Indian flap-shelled turtle (Lissemys punctata punctata)

We report an atypical mycobacterial infection in an Indian flap-shelled turtle, Lissemys punctata punctata, that died in an aquarium in Japan. At necropsy, the turtle showed multiple white nodules on the capsular surface and parenchyma of various organs such as the liver, spleen, intestine, and lung. Histologically, granulomatous inflammation surrounding a central zone of necrosis was observed. Sections stained by the Ziehl-Neelsen method revealed numerous acid-fast bacilli in the cytoplasm of macrophages and in the central area of necrosis. The organisms were identified as a mycobacterial species by PCR and nucleotide sequence analysis and revealed 98-100% homology to M. ulcerans. This is, to our knowledge, the first report of mycobacteriosis due to M. ulcerans in a turtle.     

Relationship between N2O and NO emission potentials and soil properties in Japanese forest soils

To determine the relationship between nitrous oxide (N₂O) and nitric oxide (NO) emission rates and soil properties in forest soils, N₂O and NO emission rates in soils were measured in incubation experiments under standardized temperature and water conditions (water content at a water-holding capacity of 60%) using soils packed into a cylindrical core, and variations in the soil properties were also determined. The N₂O emission rates from nitrification and from denitrification were determined separately using a nitrification inhibitor (10 Pa acetylene). Soil samples were taken from 25 forest stands in a central temperate area of Japan. The N₂O and NO emission rates were highly variable, even under the standardized temperature and water-holding capacity (60%) conditions. According to a partial least squared regression model analysis, the C:N ratio and pH strongly affected the N₂O emission rate, whereas     , water-soluble Al and the C:N ratio strongly affected the NO emission rate. The C:N ratio negatively affected the emission rate of both N oxide gases, suggesting that N mineralization is an important factor in the rates of N oxide gas emission. The acetylene inhibition experiment showed that N₂O emission from denitrification was positively affected by pH, water-filled pore space and filling density, and negatively affected by the C:N ratio, total carbon and total nitrogen.     

Erratum to: Mechanical properties of wood in an unstable state due to temperature changes,and analysis of the relevant mechanism III: Effect of quenching on stress relaxation of chemically modified woods

In order to understand the mechanism of destabilization occurring when wood is quenched, we applied chemical modifications, and controlled the number of moisture adsorption sites in wood. The degree of destabilization was evaluated according to the fluidity (1-E _t/E ₀), increase in fluidity, and relative fluidity in relation to the nonmodified wood, and was discussed by comparing these quantities with the hygroscopicity or swelling of wood. We found that destabilization of chemically modified wood was lower than that in nonmodified wood, and the amount of adsorbed water controlled the magnitude of flow of wood. Moreover, according to the analysis of water state by the Hailwood-Horrobin equation, it was shown that the function of dissolved water to the fluidity is almost identical for both chemical modifications, whereas hydrated water has more effect on acetylated wood than on formaldehydetreated wood. We speculate that the motion of water molecules due to quenching accompanied with the redistribution of energy resulting from the exchange of their potential energy and movement to attain a new balance, and the introduced acetyl groups and cross-linking restrict the water molecule movement. An erratum to this article is available at .     

Software development for estimating the concentration of radioactive cesium in the skeletal muscles of cattle from blood samples

The 2011 earthquake severely damaged the Fukushima Daiichi Nuclear Power Plant (FNPP), resulting in the release of large quantities of radioactive material into the environment. The deposition of these radionuclides in rice straw as livestock feed led to the circulation of contaminated beef in the market. Based on the safety concern of the consumers, a reliable method for estimating concentrations of radioactive cesium in muscle tissue is needed. In this study, we analyzed the concentrations of radioactive cesium in the blood and skeletal muscle of 88 cattle, and detected a linear correlation between them. We then developed software that can be used to estimate radioactive cesium concentrations in muscle tissue from blood samples. Distribution of this software to the livestock production field would allow us to easily identify high‐risk cattle, which would be beyond the safety regulation, before shipping out to the market. This software is planned to be released as freeware. This software would contribute to food safety, and aid the recovery of the livestock industry from the damage creacted by the 2011 Tohoku earthquake and tsunami.     

Genetic and antigenic characterization of bovine viral diarrhea viruses isolated from cattle in Hokkaido,Japan

In our previous study, we genetically analyzed bovine viral diarrhea viruses (BVDVs) isolated from 2000 to 2006 in Japan and reported that subgenotype 1b viruses were predominant. In the present study, 766 BVDVs isolated from 2006 to 2014 in Hokkaido, Japan, were genetically analyzed to understand recent epidemics. Phylogenetic analysis based on nucleotide sequences of the 5′-untranslated region of viral genome revealed that 766 isolates were classified as genotype 1 (BVDV-1; 544 isolates) and genotype 2 (BVDV-2; 222). BVDV-1 isolates were further divided into BVDV-1a (93), 1b (371) and 1c (80) subgenotypes, and all BVDV-2 isolates were grouped into BVDV-2a subgenotype (222). Further comparative analysis was performed with BVDV-1a, 1b and 2a viruses isolated from 2001 to 2014. Phylogenetic analysis based on nucleotide sequences of the viral glycoprotein E2 gene, a major target of neutralizing antibodies, revealed that BVDV-1a, 1b and 2a isolates were further classified into several clusters. Cross-neutralization tests showed that BVDV-1b isolates were antigenically different from BVDV-1a isolates, and almost BVDV-1a, 1b and 2a isolates were antigenically similar among each subgenotype and each E2 cluster. Taken together, BVDV-1b viruses are still predominant, and BVDV-2a viruses have increased recently in Hokkaido, Japan. Field isolates of BVDV-1a, 1b and 2a show genetic diversity on the E2 gene with antigenic conservation among each subgenotype during the last 14 years.     

Spatial variations in nitrous oxide and nitric oxide emission potential on a slope of Japanese cedar (Cryptomeria japonica) forest

To quantify the spatial variation and spatial structure of nitrous oxide (N₂O) and nitric oxide (NO) emission from forest soils, we measured N₂O and NO emission rates from surface soil cores taken at 1 m intervals on a cross-line transect (65 m × 20 m) on a slope of Japanese cedar ( Cryptomeria japonica ) forest in a temperate region of central Japan and analyzed the spatial dependency of N oxide gas emissions using geostatistics. We divided N₂O emission into N₂O from denitrification and N₂O from nitrification using the acetylene inhibition method. According to the geostatistical analysis, N₂O emission rates on the slope had large spatial variation and weak spatial dependency. This weak spatial dependency was caused by the inordinately high N₂O emissions on the slope, which were derived mainly from denitrification. In contrast, NO emission rate on the slope had large spatial variation, but strong spatial dependency and a distinct spatial distribution related to slope position, that is, high in the middle of the slope and low in the shoulder and the foot of the slope. The CN ratio and water-filled pore space were the dominant factors controlling NO emission rate on a slope. Our results suggest that spatial information about topographic factors helps to improve the estimation of both N₂O emission and NO emission from forest soils.