Enhancement of electrolytic mass transfer around spheres by applying static magnetic fields

金沢大学大学院自然科学研究科エコサイクルシステム金沢大学工学部The effect of applying a static magnetic field on mass transfer rate in diffusion-controlled electroreduction was studied experimentally around single spheres of diameters 8 to 14 mm under the condition of laminar natural convection. The electrolytic solution of the system K"SUB 3" Fe(CN)"SUB 6" -K"SUB 4" Fe(CN)"SUB 6" with a supporting electrolyte was employed and the magnetic field was applied to the cathode in the horizontal or vertical direction and up to 336 mT in flux density. By applying the magnetic field in every direction, the mass transfer rate was enhanced more than 50% at the highest magnetic flux density, compared to the simple natural convection case. (from Authors)

Inhibition of FGF-Induced ␣A-Crystallin Promoter Activity in Lens Epithelial Explants by TGF␤

PURPOSE. Fibroblast growth factor (FGF) plays a key role in normal lens biology, and recent studies suggest that transforming growth factor (TGF)-␤ is involved in the origin of certain forms of cataract. In the current study, the effects of FGF and TGF␤ on ␣A-crystallin promoter activity were investigated. METHODS. Rat lens epithelial explants were cultured with or without growth factors after transfecting with the firefly luciferase reporter gene driven by either the mouse ␣A-crystallin promoter region or a control simian virus (SV)40 promoter. RESULTS. FGF-2, at a concentration that induced lens fiber differentiation, strongly stimulated ␣A-crystallin promoter activity in explants at 3 to 4 days of culture, whereas SV40 promoter control specimens showed no comparable increase. At lower concentrations of FGF, sufficient to induce cell proliferation but not differentiation, there was only a slight increase in ␣A-crystallin promoter activity. Stimulation of ␣A-crystallin promoter activity induced by the fiber-differentiating concentration of FGF was virtually abolished by as little as 25 pg/ml TGF␤2, but the onset of fiber-specific ␤-crystallin accumulation was not prevented at this concentration. Phase-contrast microscopy revealed overt cataractous changes only at concentrations of TGF␤ more than 25 pg/ml. CONCLUSIONS. The stimulation of ␣A-crystallin promoter activity by FGF is consistent with its role in inducing accumulation of crystallins in explants. The blocking effect of TGF␤ on this process, even at a concentration too low to induce obvious pathologic changes, indicates the potential for TGF␤ to disturb ␣A-crystallin gene expression during early fiber differentiation. (Invest Ophthalmol Vis Sci

A Possible Trifunctional β-Carotene Synthase Gene Identified in the Draft Genome of Aurantiochytrium sp. Strain KH105

Labyrinthulomycetes have been regarded as a promising industrial source of xanthophylls, including astaxanthin and canthaxanthin, polyunsaturated fatty acids such as docosahexaenoic acid and docosapentaenoic acid, ω-3 oils, and terpenic hydrocarbons, such as sterols and squalene. A Thraustochytrid, Aurantiochytrium sp. KH105 produces carotenoids, including astaxanthin, with strong antioxidant activity. To gain genomic insights into this capacity, we decoded its 97-Mbp genome and characterized genes for enzymes involved in carotenoid biosynthesis. Interestingly, all carotenogenic genes, as well as other eukaryotic genes, appeared duplicated, suggesting that this strain is diploid. In addition, among the five genes involved in the pathway from geranylgeranyl pyrophosphate to astaxanthin, geranylgeranyl phytoene synthase (crtB), phytoene desaturase (crtI) and lycopene cyclase (crtY) were fused into single gene (crtIBY) with no internal stop codons. Functionality of the trifunctional enzyme, CrtIBY, to catalyze the reaction from geranylgeranyl diphosphate to β-carotene was confirmed using a yeast assay system and mass spectrometry. Furthermore, analyses of differential gene expression showed characteristic up-regulation of carotenoid biosynthetic genes during stationary and starvation phases under these culture conditions. This suggests genetic engineering events to promote more efficient production of carotenoids. We also showed an occurrence of crtIBY in other Thraustochytrid species

Long-Term Outcome of Endoscopic Balloon Dilation in Obstructive Gastrointestinal Crohn's Disease: A Prospective Long-Term Study

Background The short- and long-term results of balloon dilation therapy in Crohn's patients with non-anastomotic obstructive gastrointestinal lesions are investigated

Iron accumulation causes impaired myogenesis correlated with MAPK signaling pathway inhibition by oxidative stress

Skeletal muscle atrophy is caused by disruption in the homeostatic balance of muscle degeneration and regeneration under various pathophysiological conditions. We have previously reported that iron accumulation induces skeletal muscle atrophy via a ubiquitin ligase-dependent pathway. However, the potential effect of iron accumulation on muscle regeneration remains unclear. To examine the effect of iron accumulation on myogenesis, we used a mouse model with cardiotoxin (CTX)-induced muscle regeneration in vivo and C2C12 mice myoblast cells in vitro. In mice with iron overload, the skeletal muscles exhibited increased oxidative stress and decreased expression of satellite cell markers. Following CTX-induced muscle injury, these mice also displayed delayed muscle regeneration with a decrease in the size of regenerating myofibers, reduced expression of myoblast differentiation markers, and decreased phosphorylation of mitogen-activated protein kinase signaling pathways. In vitro, iron overload also suppressed the differentiation of C2C12 myoblast cells, but the suppression could be reversed by superoxide scavenging using tempol. Excess iron inhibits myogenesis via oxidative stress, leading to an imbalance in skeletal muscle homeostasis