Endothelin-1, an ulcer inducer, promotes gastric ulcer healing via mobilizing gastric myofibroblasts and stimulates production of stroma-derived factors

Endothelin (ET)-1 is a potent inducer of peptic ulcers. The roles of ET-1 in ulcer healing, however, have remained unclear, and these were investigated in mice. Gastric ulcers were induced in mice by serosal application of acetic acid. Three days later, mice were given a neutralizing ET-1 antibody or nonimmunized serum. The ulcer size, amount of fibrosis and myofibroblasts, and localization of ET-1 and ET(A/B) receptors were analyzed. To elucidate the mechanisms underlying the effects of ET-1, we examined the proliferation, migration, and release of growth and angiogenic factors in gastric myofibroblasts with or without ET-1. The expression of prepro-ET-1 (an ET-1 precursor) and ET-converting enzyme-1 was examined in gastric myofibroblasts using RT-PCR. Immunoneutralization of ET-1 delayed gastric ulcer healing. The areas of fibrosis and myofibroblasts were smaller in the anti-ET-1 antibody group than in the control. ET-1 was expressed in the gastric epithelium, myofibroblasts, and other cell types. ET(A) receptors, but not ET(B) receptors, were present in myofibroblasts. ET-1 increased proliferation and migration of gastric myofibroblasts. ET-1 stimulated the release of hepatocyte growth factor, VEGF, PGE(2), and IL-6 from gastric myofibroblasts. mRNA for prepro-ET-1 and ET-converting enzyme-1 was also expressed. ET-1 promotes the accumulation of gastric myofibroblasts and collagen fibrils at gastric ulcers. ET-1 also stimulates migration and proliferation of gastric myofibroblasts and enhances the release of growth factors, angiogenic factors, and PGE(2). Thus ET-1 has important roles not only in ulcer formation but also in ulcer healing via mobilizing myofibroblasts and inducing production of stroma-derived factors.     

Gene trapping in Arabidopsis reveals genes involved in vascular development

The procambium is made up of stem cells that give rise to various vascular cells in plants. To understand the molecular nature of procambium cells, we tried to identify genes that characterize procambium cells using Arabidopsis gene trap lines. Among 26,000 gene trap lines, we found 67 lines in which beta-glucuronidase (GUS) staining occurred along vascular tissues in cotyledons and/or adult leaves. Although four gene trap lines showed procambium-preferential GUS expression, their expression patterns differed from each other during procambium development in root tips and young rosette leaves. Genomic regions flanking the gene trap insertion points in 25 of the 67 lines were determined, including three lines showing preferential GUS staining of the procambium. The three procambium-related genes encoded PINHEAD, katanin and an unknown DUF740 domain-containing protein. We discuss procambium development based on the functions and the differential GUS staining patterns of the procambium-related genes.     

Sentence alignment using feed forward neural network

Parallel corpora have become an essential resource for work in multi lingual natural language processing. However, sentence aligned parallel corpora are more efficient than non-aligned parallel corpora for cross language information retrieval and machine translation applications. In this paper, we present a new approach to align sentences in bilingual parallel corpora based on feed forward neural network classifier. A feature parameter vector is extracted from the text pair under consideration. This vector contains text features such as length, punctuate score, and cognate score values. A set of manually prepared training data has been assigned to train the feed forward neural network. Another set of data was used for testing. Using this new approach, we could achieve an error reduction of 60% over length based approach when applied on English-Arabic parallel documents. Moreover this new approach is valid for any language pair and it is quite flexible approach since the feature parameter vector may contain more/less or different features than that we used in our system such as lexical match feature.     

Ca2+ transient induced by extracellular changes in osmotic pressure in Arabidopsis leaves: differential involvement of cell wall-plasma membrane adhesion

We investigated the mechanism underlying the perception of extracellular changes in osmotic pressure in Vallisneria gigantea Graebner and transgenic Arabidopsis thaliana (L.) Heynh. expressing cytoplasmic aequorin. Hypertonic and hypotonic treatments of A. thaliana leaves each rapidly induced a Ca2+ transient. Both responses were essentially dependent on the presence of extracellular Ca2+ and were sensitive to Gd3+ a potential blocker of stretch-activated Ca2+ channels. Immediately after plasmolysis caused by hypertonic treatment and subsequent deplasmolysis caused by hypotonic treatment, the cells did not respond to a second hypertonic treatment and exhibited an impaired adhesion of the plasma membrane (PM) to the cell wall (CW). Recovery of the responsiveness required about 6 h. By contrast, no refractory phenomenon was observed in response to hypotonic treatment. Pretreatment with cellulase completely inhibited the Ca2+ transient induced by hypertonic treatment, but it did not affect the response to hypotonic treatment. V. gigantea mesophyll cells pretreated with cellulase exhibited an impaired adhesion of the PM to the CW. The leaf cells of multicellular plants can respond to both hypertonic and hypotonic treatments through the stretch-activated Ca2+ channels, whereas cellulase-sensitive adhesion of the PM to the CW is involved only in the response to hypertonic treatment.     

Effects of restricted feeding on daily fluctuations of hepatic functions including p450 monooxygenase activities in rats

Hepatic P450 monooxygenase activities, assessed by measurement of 7-alkoxycoumarin O-dealkylase (ACD) activities, show obvious daily fluctuations in male rats with high values during the dark period and low values during the light period. We have already confirmed that the ACD activities are controlled by the suprachiasmatic nucleus (SCN), which is well known as the oscillator of circadian rhythm. Recently, it is reported that circadian oscillators exist not only in the SCN but also in peripheral organs. To date, it is unclear which circadian oscillators predominantly drive the daily fluctuations of hepatic ACD activities. To address this question, we examined the effects of restricted feeding, which uncouples the circadian oscillators in the liver from the central pacemaker in the SCN, on the daily fluctuations in hepatic ACD activities in male rats. Here we show that restricted feeding inverts the oscillation phase of the daily fluctuations in hepatic ACD activities. Regarding the hepatic P450 content, there were no fluctuations between the light and dark periods under ad libitum and restricted feeding conditions. Therefore, it is considered that the daily fluctuations in hepatic ACD activities are predominantly driven by the circadian factors in peripheral organs rather than by the oscillator in the SCN directly.     

Total synthesis of two isoflavone C-glycosides: genistein and orobol 8-C-beta-D-glucopyranosides

Genistein and orobol 8-C-beta-D-glucopyranosides (1 and 3) were firstly synthesized in overall yields of 39% and 41% from 2,4-di-O-benzylphloroacetophenone (4), as follows: (1) the formation of the chalcone (6, 7) by aldol condensation of the benzyl-protected C-glycosylphloroacetophenone (5), a key intermediate of the total synthesis of 1 and 3 and synthesized by a C-glycosylation method involving the O-->C glycoside rearrangement of 4 in 96% yield; (2) the formation of isoflavones (10, 11 and 12, 13) by the formation of acetals by oxidative rearrangement of the protected chalcones (8 and 9) using Tl(NO3)3, followed by acid-catalyzed cyclization; (3) a final debenzylation by hydrogenolysis.