The effect of fertilization on cesium concentration of rice grown in a paddy field in Fukushima Prefecture in 2011 and 2012

After the accident of the Fukushima 1 nuclear power plant in March 2011, radioactive cesium was released and paddy field in a wide area of Fukushima Prefecture was contaminated. To reduce radioactive Cs uptake by rice, it is important to understand factors that affect Cs uptake in rice. Here we describe our study in 2011 and 2012 to investigate Cs concentration in two rice cultivars, Koshihikari and Hitomebore, the top two cultivars in Fukushima prefecture, grown under different fertilizer conditions in the contaminated paddy field. Our study demonstrated that high nitrogen and low potassium conditions increase Cs concentrations both in straw and brown rice.     

Small-scale hypoxic cultures for monitoring the spatial reorganization of glycolytic enzymes in Saccharomyces cerevisiae

At normal oxygen concentration, glycolytic enzymes are scattered in the cytoplasm of Saccharomyces cerevisiae. Under hypoxia, however, most of these enzymes, including enolase, pyruvate kinase, and phosphoglycerate mutase, spatially reorganize to form cytoplasmic foci. We tested various small-scale hypoxic culture systems and showed that enolase foci formation occurs in all the systems tested, including in liquid and on solid media. Notably, a small-scale hypoxic culture in a bench-top multi-gas incubator enabled the regulation of oxygen concentration in the media and faster foci formation. Here, we demonstrate that the foci formation of enolase starts within few hours after changing the oxygen concentration to 1% in a small-scale cultivation system. The order of foci formation by each enzyme is tightly regulated, and of the three enzymes, enolase was the fastest to respond to hypoxia. We further tested the use of the small-scale cultivation method to screen reagents that can control the spatial reorganization of enzymes under hypoxia. An AMPK inhibitor, dorsomorphin, was found to delay formation of the foci in all three glycolytic enzymes tested. These methods and results provide efficient ways to investigate the spatial reorganization of proteins under hypoxia to form a multienzyme assembly, the META body, thereby contributing to understanding and utilizing natural systems to control cellular metabolism via the spatial reorganization of enzymes.     

Inhibition of FGF10-ERK signal activation suppresses intraductal papillary neoplasm of the bile duct and its associated carcinomas

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Fermented milk, Kefram-Kefir enhances glucose uptake into insulin-responsive muscle cells

Diminution of insulin-responses in the target organ is the primary cause of non-insulin dependent diabetes mellitus (NIDDM).It is thought to be correlated to the excessive production of reactive oxygen species (ROS). In this article, we attempted to evaluate whether fermented milk, Kefram-Kefir known as an antioxidant, reduces the cellular ROS levels and can stimulate the glucose uptake in L6 skeletal muscle cells. Water-soluble or chloroform/methanol-extracted fractions from Kefram-Kefir were examined to evaluate the glucose uptake ability of L6 myotubes.As a result, the water-soluble fraction augmented the uptake of glucose in L6 myotubes both in the presence and absence of insulin stimulation. Estimation of intracellular ROS level revealed that the water-soluble fraction of Kefram-Kefir reduced the intracellular ROS level on both the undifferentiated and differentiated L6 cells. Especially, glucose uptake was augmented up to six times with the addition of water-soluble fraction in the insulin-stimulated L6 myotubes. Glucose transport determination revealed that the active agent in Kefram-Kefir was resistant to autoclave and stable in pH range from 4 to 10, and the small molecule below the molecular weight of 1000. Furthermore, this augmentation was inhibited in the presence of phosphatidylinositol 3-kinase (PI 3-kinase) inhibitor wortmannin. Considering together with the reports that PI 3-kinase is locatedin the insulin signaling pathway and the participation in the translocation of glucose transporter 4 to the cell membrane, it is suggested that the water-soluble fraction of Kefram-Kefir activates PI 3-kinase or other upstream molecules in the insulin signaling pathway, which resulted in the augmentation of glucose uptake and its specific inhibition by wortmannin. This revised version was published online in August 2006 with corrections to the Cover Date.     

Lipid dependence of activity-temperature relationship of (Na+, K+)-activated ATPase

The lipid moieties of (Na⁺, K⁺)-dependent ATPases of bovine cerebral cortex and bullfrog kidney were partly replaced with extraneous lipids, and temperature effects on their activities were investigated. The effects were found to depend on the lipid moiety, and to be constant with a given lipid regardless of the enzyme source.     

Genes Required for Plasmid R64 Thin-Pilus Biogenesis: Identification and Localization of Products of the pilK, pilM, pilO, pilP, pilR, and pilT Genes

We have previously shown that the pilL, pilN, pilQ, pilS, pilU, and pilV genes of plasmid R64 encode outer membrane lipoprotein, secretin, cytoplasmic ATPase, major pilin, prepilin peptidase, and minor pilin, respectively, which are required for thin-pilus formation. In this work, we characterized the products of the remaining essential genes, pilK, pilM, pilO, pilP, pilR, and pilT, with regard to their localization and processing. Overexpression systems containing pilM, pilO, and pilP genes fused with N-terminal glutathione S-transferase (GST) or a His tag were constructed. Overproduced proteins were purified and used to raise specific antibodies. Localization of PilM, PilO, and PilP proteins was performed by Western blot analysis with anti-GST-PilM, anti-PilO, and anti-PilP antibodies, respectively. The pilK, pilR, and pilT products were produced with a C-terminal His tag and then detected by anti-His tag antibody. Subcellular fractionation experiments with Escherichia coli cells producing R64 thin pili revealed that PilK, PilM, and PilR are inner membrane proteins, and PilP and PilT are periplasmic proteins. PilO protein was localized to the outer membrane in the presence of other Pil proteins, whereas it was localized to the cytoplasm in the absence of these proteins. Furthermore, the cleavage site of PilP protein was determined by N-terminal amino acid sequencing of purified mature PilP protein. We predict that PilK, PilM, PilO, PilP, and PilT proteins function as the components of the pilin transport apparatus and thin-pilus basal body.     

A life table ofMogannia iwasakii (Homoptera: Cicadiidae) in sugarcane field of Okinawa

A preliminary life table of the sugarcane cicada, Mogannia iwasakii, which became a pest of sugarcane in Okinawa recently, was presented based on the results of field survey. Mortality rates during egg and later nymphal stages were low but a remarkable reduction of the number of individuals in a cohort took place at the 1st nymphal instar, mainly due to predation by ants. Ants also killed the cicada during and just after the final ecdysis and birds concentrated their feeding on adults. Prenatal mortality of adults was, however, low in the infested area, suggesting the ‘escape’ of cicadas from the pressure of predators. This espace is considered to be a factor responsible to the maintainance of outbreak for a long time. Increase in the acreage of ratton canes and wide-use of organochlorine insecticides during the 1960's were assumed to be the factors responsible to the initial increase of this species.