Interleukin-6 family of cytokines mediate angiotensin II-induced cardiac hypertrophy in rodent cardiomyocytes

This study was designed to investigate whether angiotensin II induces the interleukin (IL)-6 family of cytokines in cardiac fibroblasts and, if so, whether these cytokines can augment cardiac hypertrophy. Angiotensin II increased IL-6, leukemia inhibitory factor (LIF) and cardiotrophin-1 mRNA by 6.5-, 10.2-, and 2.0-fold, respectively, but did not affect IL-11, ciliary neurotrophic factor, or oncostatin M in cardiac fibroblasts. Enzyme-linked immunosorbent assay revealed that angiotensin II-stimulated conditioned medium from cardiac fibroblasts contained 9.3 ng/ml IL-6 at 24 h, which was 24-fold higher than the control. It phosphorylated gp130 and STAT3 in cardiomyocytes, which was reduced with RX435 (anti-gp130 blocking antibody). It increased [(3)H]phenylalanine uptake and cell area by 44% and 86% in cardiomyocytes compared with mock medium. RX435 suppressed these increases by 26% and 38%, while TAK044 (endothelin-A/B-R blocker) suppressed them by 52% and 52%, respectively. Antisense oligonucleotides against LIF and cardiotrophin-1 blocked their up-regulation, and attenuated the conditioned medium-induced increase in [(3)H]phenylalanine uptake by 21% and 13%, respectively. The combination of antisense oligonucleotides to LIF and cardiotrophin-1 decreased their uptake by 33%. These results indicated that angiotensin II induced IL-6, LIF, and cardiotrophin-1 in cardiac fibroblasts, and that these cytokines, particularly LIF and cardiotrophin-1, activated gp130-linked signaling and contributed to angiotensin II-induced cardiomyocyte hypertrophy.     

Glycogen debranching enzyme in bovine brain

Glycogen debranching enzyme was partially purified from bovine brain using a substrate for measuring the amylo-1,6-glucosidase activity. Bovine cerebrum was homogenized, followed by cell-fractionation of the resulting homogenate. The enzyme activity was found mainly in the cytosolic fraction. The enzyme was purified 5,000-fold by ammonium sulfate precipitation, anion-exchange chromatography, gel-filtration, anion-exchange HPLC, and gel-permeation HPLC. The enzyme preparation had no alpha-glucosidase or alpha-amylase activities and degraded phosphorylase limit dextrin of glycogen with phosphorylase. The molecular weight of the enzyme was 190,000 and the optimal pH was 6.0. The brain enzyme differed from glycogen debranching enzyme of liver or muscle in its mode of action on dextrins with an alpha-1,6-glucosyl branch, indicating an amino acid sequence different from those of the latter two enzymes. It is likely that the enzyme is involved in the breakdown of brain glycogen in concert with phosphorylase as in the cases of liver and muscle, but that this proceeds in a somewhat different manner. The enzyme activity decreased in the presence of ATP, suggesting that the degradation of brain glycogen is controlled by the modification of the debranching enzyme activity as well as the phosphorylase.     

Mechanism of regulation of the hypoxia-inducible factor-1 alpha by the von Hippel-Lindau tumor suppressor protein

In normoxic cells the hypoxia-inducible factor-1 alpha (HIF-1 alpha) is rapidly degraded by the ubiquitin-proteasome pathway, and activation of HIF-1 alpha to a functional form requires protein stabilization. Here we show that the product of the von Hippel-Lindau (VHL) tumor suppressor gene mediated ubiquitylation and proteasomal degradation of HIF-1 alpha under normoxic conditions via interaction with the core of the oxygen-dependent degradation domain of HIF-1 alpha. The region of VHL mediating interaction with HIF-1 alpha overlapped with a putative macromolecular binding site observed within the crystal structure of VHL. This motif of VHL also represents a mutational hotspot in tumors, and one of these mutations impaired interaction with HIF-1 alpha and subsequent degradation. Interestingly, the VHL binding site within HIF-1 alpha overlapped with one of the minimal transactivation domains. Protection of HIF-1 alpha against degradation by VHL was a multistep mechanism, including hypoxia-induced nuclear translocation of HIF-1 alpha and an intranuclear hypoxia-dependent signal. VHL was not released from HIF-1 alpha during this process. Finally, stabilization of HIF-1 alpha protein levels per se did not totally bypass the need of the hypoxic signal for generating the transactivation response.     

Interaction of glyceraldehyde-3-phosphate dehydrogenase with the cytoplasmic pole of band 3 from bovine erythrocyte membrane: the mode of association and identification of the binding site of band 3 polypeptide

Four fragments derived from the cytoplasmic pole of bovine band 3 were isolated, and their ability to bind glyceraldehyde-3-phosphate dehydrogenase from bovine erythrocyte and their amino-terminal primary structure were examined. It was suggested that the 50-kDa fragment, an entire cytoplasmic pole of band 3, contained the blocked amino-terminal end of band 3. Three other fragments, 45-, 39-, and 38-kDa fragments, were produced by cleavage at distances of molecular weight 5000, 11,000, and 12,000 respectively, from the amino-terminus of the 50-kDa fragment. Among these, the 50- and 45-kDa fragments complexed with the enzyme to inhibit its catalytic activity under conditions of low ionic strength, in a fashion similar to that in humans. Affinity for the enzyme was not significantly affected by disruption of the higher order structure of the fragments. The enzyme was found to be inactivated by association with synthetic polyanions, accompanied by conformational alteration. This supports participation of electrostatic interactions as the holding force between the enzyme and band 3, as suggested by I-H. Tsai et al. [1982) J. Biol. Chem. 257, 1438-1442). The 45-kDa fragment was just as potent an inhibitor of the enzyme as the parent fragment, and its amino-terminal region displayed a polyanionic character. These results allow us to map the enzyme binding site of bovine band 3 to a distance of molecular weight approximately 5000 from the amino-terminal end of band 3. Furthermore, comparison of sequence data from different species showed that the species-specific region of band 3 polypeptide centers around the amino-terminal portion.     

Ecological impacts of the 2011 Tohoku Earthquake Tsunami on aquatic animals in rice paddies

The 2011 Tohoku Earthquake Tsunami hit the Pacific coast of eastern Japan on March 11, 2011 and disturbed various ecosystems, including rice paddies along the coast. In Miyagi Prefecture, located in the Tohoku Region, a total of 12685 ha, or about 11.5 % of the rice paddies, were inundated and damaged by the tsunami. Although rice paddies are artificially constructed, they have long been used by many kinds of aquatic animals as habitats. To assess impacts of the 2011 Tohoku Earthquake Tsunami on aquatic animals inhabiting the rice paddies, census surveys were conducted at inundated and non-inundated rice paddies at six sites along the coast of Miyagi Prefecture from June to July 2012. This was 30–60 days after the first transplanting of rice seedling in inundated rice paddies following the tsunami. In the surveys a total of 100 aquatic animal taxa, 72 from inundated and 86 from non-inundated rice paddies, were found. Although the taxonomic richness and composition differed among the sites, the total number of observations of walk dispersers and obligatory aquatic animals without resting stages were significantly lower in inundated than in non-inundated rice paddies. However, no notable difference was detected in taxonomic richness and the total number of observations of flight dispersers and obligatory aquatic animals with resting stages between inundated and non-inundated rice paddies. The results showed that the tsunami had a substantial impact on freshwater animals but that restoration of the paddies for rice cultivation enhanced rapid recolonization by aquatic animals with high dispersal abilities and resting stages.     

Community structures of Mesostigmata, Prostigmata and Oribatida in broad-leaved regeneration forests and conifer plantations of various ages

The community structures of Mesostigmata, Prostigmata, and Oribatida in the soil of broad-leaved regeneration forests and conifer plantations of various ages were assessed alongside soil and plant environmental variables using three response metrics (density, species richness, and species–abundance distribution). The density and species richness of mites recovered swiftly after clear-cutting or replanting. Oribatid mites dominated the soil mite communities in terms of densities and species richness for both forest types. Soil mite communities in broad-leaved forests was related to forest age, the crown tree communities index, and forest-floor litter weight. In contrast, soil mite communities in the conifer plantation sites were related to various indices of understory plants. The development of the understory plants was synchronized with the silvicultural schedules, including a closed canopy and thinning. Such a conifer plantation management may affect indirectly the community of mites.     

Proteomic study of β-aminobutyric acid-mediated cadmium stress alleviation in soybean

The present study highlights the protective role of β-aminobutyric acid (BABA) in alleviating cadmium (Cd) stress in soybean. Proteomic analyses revealed that out of 66 differentially abundant protein spots in response to Cd challenge, 17 were common in the leaves of BABA-primed and non-primed plants. Oxygen-evolving enhancer protein 1 and ribulose bisphosphate carboxylase small chain 1 were detected in increase abundance in both groups of leaves. Among the 15 commonly decreased protein spots, the relative intensity levels of heat shock cognate 70-kDa protein, carbonic anhydrase, methionine synthase, and glycine dehydrogenase were partially restored after BABA treatment. Moreover, BABA priming significantly enhanced the abundance of the defense-related protein peroxiredoxin and glycolytic enzymes in response to Cd exposure. Additionally, the impact of Cd on the physiological state of BABA-primed and non-primed plants was analyzed using a biophoton technique. The finding of comparatively low biophoton emission in BABA-primed leaves under Cd stress indicates that these plants experienced less oxidative damage than that of non-primed plants. Proteomic study coupled with biophoton analysis reveals that BABA pretreatment helps the plants to combat Cd stress by modulating plants' defence mechanism as well as activating cellular detoxification system to protect the cells from Cd induced oxidative stress damages.     

Phase variation of the opacity outer membrane protein controls invasion by Neisseria gonorrhoeae into human epithelial cells.

Neisseria gonorrhoeae is a facultative intracellular bacterium capable of penetrating into certain human epithelial cell types. In order to identify gonococcal factors essential for invading Chang human conjunctiva cells, a gentamicin selection assay for the quantification of viable intracellular bacteria was used in conjunction with microscopy. The results demonstrate a correlation between the invasive behaviour of gonococci and the expression of Opa proteins, a family of variable outer membrane proteins present in all pathogenic Neisseria species. However, only particular Opa proteins supported invasion into Chang cells as indicated by the use of two unrelated gonococcal strains. Invasion was sensitive to cytochalasin D, and strong adherence mediated by the Opa proteins appeared to be essential for the internalization of gonococci. In contrast pili, which also conferred binding to Chang conjunctiva cells, did not support cellular invasion but rather were inhibitory.