Oligosaccharide-Related Epitope Specific for a Brain-Specific Glycoprotein, 1D4 Antigen

The characteristics of glycosylation of a brain-specific glycoprotein, 1D4 antigen, and the epitope recognized by its monoclonal antibody were studied. Removal of high-mannose and hybrid types of N-linked oligosaccharides by treatment with endoglycosidase H converted the molecular mass of the 1D4 antigen from 89 kDa to 78 kDa, but did not affect its reactivity with the 1D4 monoclonal antibody. Removal of all types of N-linked oligosaccharides by treatment with glycopeptidase F or removal of both N- and O-linked oligosaccharides by chemical treatment caused both reduction of the molecular mass of the antigen to 63 kDa and loss of its reactivity with the monoclonal antibody. These results suggest that the 1D4 monoclonal antibody recognizes a complex-type oligosaccharide-related epitope specific for the 1D4 antigen. Results also showed that N-linked glycosylation was not responsible for the charge heterogeneity of the 1D4 antigen. The oligosaccharide chain-related epitope was detected in rat brain but not in mouse, rabbit, or bovine brain, but the 1D4 antigen was recognized in rat and mouse brains with antiserum (polyclonal antibodies). These findings indicate that the oligosaccharide-related epitope is species specific. Furthermore, results with neuraminidase-treated 1D4 antigen indicated that sialic acids were not involved in the oligosaccharide-related epitope. These findings suggest that the 1D4 antigen may have the oligosaccharide structure specific for rat brain and itself.     

Soil-nutrient availability and the nutrient-use efficiencies of forests along an altitudinal gradient on Yakushima Island,Japan

The vegetation on Yakushima Island, Japan, grows on soils derived from Akahoya volcanic ash, released from the Kikai Caldera about 7300 years ago. The eruption was devastating and it is believed that primary succession and soil formation reinitiated across all altitudes at this point. We hypothesize that the concentrations of soil total phosphorus (P) and labile P fractions increase with increasing altitude because the soil formation has progressed less in upslope areas as a result of the cooler temperature and because of the ample P source of the volcanic ash. Conversely, we hypothesize that the concentration of soil inorganic nitrogen (N) decreases with increasing altitude. Available soil P and N would result in increasing P limitation downslope and increasing N limitation upslope, respectively. We studied soil P fractions and soil inorganic N, and P- and N-use efficiencies of the seven forests on Yakushima along an elevation gradient (170–1550 m a.s.l.). Contrary to our hypotheses, soil total P, labile soil P fractions, and inorganic N decreased with increasing altitude. The P- and N-use efficiencies of the forests were negatively correlated with the concentration of soil total active P (total P minus occluded P) and inorganic N, respectively. We suggest that progressive soil acidity and slower decomposition under cooler and wetter environments upslope must have dissolved the P contained in volcanic ash and accelerated P leaching. Forest ecosystems on Yakushima that show a distinct altitudinal zonation are, therefore, characterized by increasing P and N shortage with increasing altitude.     

The purification of methionine sulfoxide reductase from Escherichia coli

A sensitive assay, based on the acylation of tRNA^Met, has been developed to measure the enzymatic reduction of methionine sulfoxide to methionine. Using this assay, methionine sulfoxide reductase has been purified to near homogeneity from extracts of Escherichia coli.     

Preparation and characterization of water-soluble chitin phosphate

New water-soluble chitin derivatives, chitin phosphate of various degrees of substitution, were successfully prepared by the reaction of chitin with phosphorus pentoxide in methanesulphonic acid. These materials behaved hydrodynamically as typical polyelectrolyte, and showed high ability to adsorb metal ions.     

Impact of Acacia bark extract tablets on the skin of healthy humans: a randomized,double-blind,placebo-controlled study

This study investigated the effects of proanthocyanidins derived from Acacia (Acacia mearnsii) bark extract in healthy Japanese adult subjects experiencing uncomfortable skin symptoms. All subjects were randomly allocated into two groups (n = 33 each) using a computerized random-number generator. The subjects received either Acacia bark extract tablets or placebo for 8 weeks. Evaluations included water content in the stratum corneum, transepidermal water loss (TEWL), Skindex-16, dermatology life quality index (DLQI), visual analog scale for desire to scratch, and blood tests. At 4 weeks, the symptom/feeling score of DLQI, subjective symptoms related to uncomfortable skin, and the desire to scratch were significantly reduced in the intervention group than in the placebo group. At 8 weeks, the intervention group exhibited significantly lower TEWL on facial skin than that in the placebo group. In conclusion, the intake of Acacia bark extract tablets reduced TEWL and improved dry and uncomfortable skin.     

Novel roles of formin mDia2 in lamellipodia and filopodia formation in motile cells

Actin polymerization-driven protrusion of the leading edge is a key element of cell motility. The important actin nucleators formins and the Arp2/3 complex are believed to have nonoverlapping functions in inducing actin filament bundles in filopodia and dendritic networks in lamellipodia, respectively. We tested this idea by investigating the role of mDia2 formin in leading-edge protrusion by loss-of-function and gain-of-function approaches. Unexpectedly, mDia2 depletion by short interfering RNA (siRNA) severely inhibited lamellipodia. Structural analysis of the actin network in the few remaining lamellipodia suggested an mDia2 role in generation of long filaments. Consistently, constitutively active mDia2 (ΔGBD-mDia2) induced accumulation of long actin filaments in lamellipodia and increased persistence of lamellipodial protrusion. Depletion of mDia2 also inhibited filopodia, whereas expression of ΔGBD-mDia2 promoted their formation. Correlative light and electron microscopy showed that ΔGBD-mDia2–induced filopodia were formed from lamellipodial network through gradual convergence of long lamellipodial filaments into bundles. Efficient filopodia induction required mDia2 targeting to the membrane, likely through a scaffolding protein Abi1. Furthermore, mDia2 and Abi1 interacted through the N-terminal regulatory sequences of mDia2 and the SH3-containing Abi1 sequences. We propose that mDia2 plays an important role in formation of lamellipodia by nucleating and/or protecting from capping lamellipodial actin filaments, which subsequently exhibit high tendency to converge into filopodia.     

Complete Genome Sequences of Two Helicobacter pylori Bacteriophages Isolated from Japanese Patients

Helicobacter pylori causes peptic ulcers and gastric cancer, which lead to significantly higher morbidity in Japan than elsewhere in the world. As bacteriophage (phage) and host bacteria coevolve, the study of H. pylori phages is important to extend understanding of the evolution and pathogenesis of H. pylori. Here we report two complete genome sequences of H. pylori phages KHP30 and KHP40, which were released spontaneously from the most pathogenic East Asian-type isolates from Japanese patients.     

5'-monohydroxyphylloquinone is the dominant naphthoquinone of PSI in the green alga Chlamydomonas reinhardtii

Thylakoid membranes contain two types of quinones, benzoquinone (plastoquinone) and naphthoquinone, which are involved in photosynthetic electron transfer. Unlike the benzoquinone, the chemical species of naphthoquinone present (phylloquinone, menaquinone-4 and 5'-monohydroxyphylloquinone) varies depending on the oxygenic photosynthetic organisms. The green alga Chlamydomonas reinhardtii has been used as a model organism to study the function of the naphthoquinone bound to PSI. However, the level of phylloquinone and the presence of other naphthoquinones in this organism remain unknown. In the present study, we found that 5'-monohydroxyphylloquinone is the predominant naphthoquinone in cell and thylakoid extracts based on the retention time during reverse phase HPLC, absorption and mass spectrometry measurements. It was shown that 5'-monohydroxyphylloquinone is enriched 2.5-fold in the PSI complex as compared with thylakoid membranes but that it is absent from PSI-deficient mutant cells. We also found a small amount of phylloquinone in the cells and in the PSI complex and estimated that accumulated 5'-monohydroxyphylloquinone and phylloquinone account for approximately 90 and 10%, respectively, of the total naphthoquinone content. The ratio of these two naphthoquinones remained nearly constant in the cells and in the PSI complexes from logarithmic and stationary cell growth stages. We conclude that both 5'-monohydroxyphylloquinone and phylloquinone stably co-exist as major and minor naphthoquinones in Chlamydomonas PSI.