The effect of amino acids on the C₁₄-sphingosine-triggered germination of Nomuraea rileyi, and surface amino acids on Spodoptera litura fabricius

D-erythro-C??-Sphingosine (C??-Sph) accelerated the germination of Nomuraea rileyi in a solution containing peptone, but activity declined to a large degree in water. This suggests the presence of a co-factor in C??-Sph-triggered germination. Since the main role of peptone is to supply nitrogen constituents, we examined the effects of various nitrogen constituents. It was found that Ala and His were highly effective for C??-Sph-triggered germination.     

Assessing the status of three mangrove species restored by the local community in the cyclone-affected area of the Ayeyarwady Delta,Myanmar

This paper assesses the extent of success and failure of mangrove plantations in Myanmar, restored by local people with the help of foresters under a community forestry program initiated in 1995. The species of these restored plantations are Avicennia officinalis, Avicennia marina and Heritiera fomes, each of which was restored on two plots, one on low and one on high ground, yielding a total of six plots. These plots have been continuously monitored in order to investigate survival and growth rates. The plots were established on abandoned land that had been previously used for paddy cultivation. Cyclone Nargis hit these plantations during the monitoring period, at the beginning of May, 2008. As a consequence, the survival rates of A. officinalis on low ground and A. marina on high ground declined slightly, but the overall affect was not severe. Excluding individuals affected by the cyclone, height and diameter growth of A. officinalis and A. marina were significantly higher on low ground than on high ground, i.e. on sites thought to be consistently similar to the natural habitats of these species. Contrary to these two Avicennia species, the height growth of H. fomes was higher on high ground than on low ground; the diameter growth was not significantly different. As the growth of H. fomes was very slow, however, it is still not possible to describe the differences clearly. This study may provide useful guidelines for foresters and local people to establish successful mangrove restorations and to predict production from community-owned mangrove forests.     

Molecular cloning and characterization of a beta-L-Arabinobiosidase in Bifidobacterium longum that belongs to a novel glycoside hydrolase family

Extensin is a glycoprotein that is rich in hydroxyprolines linked to β-L-arabinofuranosides. In this study, we cloned a hypBA2 gene that encodes a novel β-L-arabinobiosidase from Bifidobacterium longum JCM 1217. This enzyme does not have any sequence similarity with other glycoside hydrolase families but has 38-98% identity to hypothetical proteins in Bifidobacterium and Xanthomonas strains. The recombinant enzyme liberated L-arabinofuranose (Araf)-β1,2-Araf disaccharide from carrot extensin, potato lectin, and Araf-β1,2-Araf-β1,2-Araf-β-Hyp (Ara(3)-Hyp) but not Araf-α1,3-Araf-β1,2-Araf-β1,2-Araf-β-Hyp (Ara(4)-Hyp) or Araf-β1,2-Araf-β-Hyp (Ara(2)-Hyp), which indicated that it was specific for unmodified Ara(3)-Hyp substrate. The enzyme also transglycosylated 1-alkanols with retention of the anomeric configuration. This is the first report of an enzyme that hydrolyzes Hyp-linked β-L-arabinofuranosides, which defines a new family of glycoside hydrolases, glycoside hydrolase family 121.     

Differential but competitive binding of Nogo protein and class i major histocompatibility complex (MHCI) to the PIR-B ectodomain provides an inhibition of cells

Binding of class I MHC molecules (MHCI) to an inhibitory receptor, PIR-B, expressed on B cells and myeloid cells provides constitutive cellular inhibition, thus ensuring peripheral tolerance. Recent unexpected findings pointed to a novel inhibitory role of PIR-B in neurite regeneration through binding to three axonal outgrowth inhibitors of myelin, including Nogo. Thus, it becomes interesting to determine whether the actions of the inhibitory myelin proteins and MHCI could coexist independently or be mutually exclusive as to the PIR-B-mediated immune and neural cell inhibition. Here, we present data supporting the competition of Nogo- and MHCI-mediated inhibition where they coexist. Kinetic analyses of Nogo and MHCI binding to the whole or a part of the recombinant PIR-B ectodomain revealed that PIR-B binds with higher affinity to Nogo than MHCI and that the MHCI binding only occurred with the N-terminal domains of PIR-B, whereas Nogo binding occurred with either the N- or C-terminal ectodomains. Importantly, kinetic tests indicated that the binding to PIR-B of Nogo and MHCI was competitive. Both endogenous and exogenous Nogo intensified the PIR-B-mediated suppression of interleukin-6 release from lipopolysaccharide-stimulated wild-type, but not PIR-B-deficient, cultured mast cells, indicating that PIR-B mediates Nogo-induced inhibition. Thus, we propose a novel mechanism by which PIR-B-mediated regulation is achieved differentially but competitively via MHCI and Nogo in cells of the immune system.     

Cyclin‐dependent kinase 9 forms a complex with GATA4 and is involved in the differentiation of mouse ES cells into cardiomyocytes

The treatment of ES cells with trichostatin A (TSA), an HDAC inhibitor, induces the acetylation of GATA4 as well as histones, and facilitates their differentiation into cardiomyocytes. Recently, we demonstrated that cyclin‐dependent kinase 9 (Cdk9), a core component of positive elongation factor‐b, is a novel GATA4‐binding partner. The present study examined whether Cdk9 forms a complex with GATA4 in mouse ES cells and is involved in their differentiation into cardiomyocytes. Mouse ES cells and Nkx2.5/GFP ES cells, in which green fluorescent protein (GFP) is expressed under the control of the cardiac‐specific Nkx2.5 promoter, were induced to differentiate on feeder‐free gelatin‐coated plates. Immunoprecipitation/Western blotting in nuclear extracts from mouse ES cells demonstrated that Cdk9 as well as cyclin T1 interact with GATA4 during myocardial differentiation. TSA treatment increased Nkx2.5/GFP‐positive cells and endogenous mRNA levels of Nkx2.5 and atrial natriuretic factor. To determine the role of Cdk9 in myocardial cell differentiation, we examined the effects of a dominant‐negative form of Cdk9 (DN‐Cdk9), which loses its kinase activity, and a Cdk9 kinase inhibitor, 5,6‐dichloro‐1‐β‐ribofuranosyl‐benzimidazole (DRB) on TSA‐induced myocardial cell differentiation. The introduction of the DN‐Cdk9 inhibited TSA‐induced increase in GFP expression in Nkx2.5/GFP ES cells. The administration of DRB into ES cells significantly inhibited TSA‐induced increase of endogenous Nkx2.5 mRNA levels in ES cells as well as GFP expression in Nkx2.5/GFP ES cells. These findings demonstrate that Cdk9 is involved in the differentiation of mouse ES cells into cardiomyocytes by interacting with GATA4. J. Cell. Physiol. 226: 248–254, 2010. © 2010 Wiley‐Liss, Inc.     

Involvement of heme oxygenase-1 induction via Nrf2/ARE activation in protection against H2O2-induced PC12 cell death by a metabolite of sesamin contained in sesame seeds

Induction of phase II antioxidant enzymes by activation of Nrf2/ARE (antioxidant response element) signaling has been considered as a promising strategy to combat with oxidative stress-related diseases. In the present study, we tested for potential effects of sesamin, a major lignan contained in sesame seeds, its stereoisomer episesamin, and their metabolites on Nrf2/ARE activation in rat pheochromocytoma PC12 cells. Luciferase reporter assays showed that primary metabolites of sesamin and episesamin, SC-1 and EC-1 were the most potent ARE activators among all tested compounds. SC-1 {(1R,2S,5R,6S)-6-(3,4-dihydroxyphenyl)-2-(3,4-methylenedioxyphenyl)-3,7-dioxabicyclo-[3,3,0]octane} enhanced nuclear translocation of Nrf2 and up-regulated expression of phase II antioxidant enzymes including heme oxygenase-1 (HO-1). Treatment with SC-1 resulted in increased phosphorylation of p38 MAP kinase and transient increase in intracellular ROS levels. N-acetylcysteine (NAC) treatment abolished p38 phosphorylation as well as HO-1 induction caused by SC-1, indicating that ROS are upstream signals of p38 in Nrf2/ARE activation by SC-1. Furthermore, preconditioning with SC-1 attenuated H(2)O(2)-induced cell death in a dose-dependent manner. Finally, treatment with a HO-1 inhibitor, Zn-protoporphyrin (ZnPP), and overexpression of a dominant-negative mutant of Nrf2 diminished SC-1-mediated neuroprotection. Our results demonstrate that SC-1 is capable of protecting against oxidative stress-induced neuronal cell death in part through induction of HO-1 via Nrf2/ARE activation, suggesting its potential to reduce oxidative stress and ameliorate oxidative stress-related neurodegenerative diseases.     

Total synthesis of (+/-)-syn-copalol

The labdane diterpene derivative, syn-copalol [(+)-5] is the alcohol part of syn-copalyl diphosphate [(+)-4]. In this paper, racemic (+/-)-5 was synthesized from a known racemic lactone in 8 steps. The current and our previous syntheses provide all four copalol derivatives [(+)-3, (-)-3 and (+/-)-5] which are required for the biosynthetic study of polycyclic diterpenes.