Structural analysis of a novel saccharide isolated from fermented beverage of plant extract

Fermented beverage of plant extract was prepared from about 50 kinds of vegetables and fruits. Natural fermentation was carried out mainly by lactic acid bacteria (Leuconostoc spp.) and yeast (Zygosaccharomyces spp. and Pichia spp.). Three kinds of saccharides have been found in this beverage and produced by fermentation. The saccharides isolated from the beverage using carbon-Celite column chromatography and preparative HPLC, were identified as a new saccharide, beta-d-fructopyranosyl-(2-->6)-d-glucopyranose, laminaribiose and maltose by examination of constituted sugars, GLC and GC-MS analyses of methyl derivatives and MALDI-TOF-MS and NMR measurements of the saccharides.     

In vitro development of polyspermic porcine oocytes: Relationship between early fragmentation and excessive number of penetrating spermatozoa

Embryo development during in vitro culture of polyspermic porcine oocytes was investigated in the present study. After in vitro fertilization (IVF) of in vitro matured oocytes, putative zygotes were centrifuged to visualize pronuclei. Two pronuclear (2PN) and poly-pronuclear (PPN) zygotes were selected and cultured in vitro. Their development to the blastocyst stage and total cell numbers, dead cell rates and ploidy at the blastocyst stage and morphology of resultant embryos after first cleavage were compared. A cleavage rate of PPN embryos was lower than that of 2PN (61.3% and 82.2%, respectively), however, the ability of cleaved embryos to develop to the blastocyst stage did not differ between the PPN and the 2PN groups (22.4% and 32.9%, respectively). Also there was no difference in total cell numbers and rates of dead cells between PPN and 2PN blastocysts. The majority of blastocysts in 2PN group were found to be diploid. In contrast, blastocysts in PPN group showed heterogeneous status in their ploidy including polyploidy and mixoploidy, whereas a remarkable proportion (31.3%) of them was found to be diploid. After the first cleavage (at 36 h after IVF), there was no difference in the number of nuclei/embryo between the two groups, nevertheless embryos in PPN group had significantly higher numbers of blastomeres than that of embryos in 2PN group, mainly due to an increased frequency of anuclear blastomeres. The present results indicate that correction of embryo ploidy in polyspermic embryos can occur during IVC. Nevertheless the frequency of partial fragmentation in polyspermic embryos is increased.     

The effects of calystegines isolated from edible fruits and vegetables on mammalian liver glycosidases

The polyhydroxylated nortropane alkaloids called calyste-ginesoccur in many plants of the Convolvulaceae, Solanaceae, andMoraceae families. Certain of these alkaloids exhibit potentinhibitory activities against glycosidases and the recentlydemonstrated occurrence of calystegines in the leaves, skins,and sprouts of potatoes (Solatium tuberosum), and in the leavesof the eggplant (S.melongena), has raised concerns regardingthe safety of these vegetables in the human diet. We have surveyedthe occurrence of calystegines in edible fruits and vegetablesof the families Convolvulaceae, Solanaceae, and Moraceae byGC-MS. Calystegines A3, B1, B2, and C1 were detected in allthe edible fruits and vegetables tested; sweet and chili peppers,potatoes, eggplants, tomatoes, Physalis fruits, sweet potatoes,and mulberries. Calystegines B1 and C1 were potent competitiveinhibitors of the bovine, human, and rat β-glucosidaseactivities, with K₁ values of 150, 10, and 1.9 µM, respectivelyfor B1 and 15,1.5, and 1 µM, respectively, for C1. CalystegineB2 was a strong competitive inhibitor of the -galactosidaseactivity in all the livers. Human β-xylosidase was inhibitedby all four nortropanes, with calystegine C1 having a K₁ of0.13 µM. Calystegines A3 and B2 selectively inhibitedthe rat liver β-glucosidase activity. The potent inhibitionof mammalian β-glucosidase and -galactosidase activitiesin vitro raises the possibility of toxicity in humans consuminglarge amounts of plants that contain these compounds. edible plants calystegines glycosidase inhibitors bovine, human, and rat liver     

Overexpression of glutathione peroxidase attenuates myocardial remodeling and preserves diastolic function in diabetic heart

Oxidative stress plays an important role in the structural and functional abnormalities of diabetic heart. Glutathione peroxidase (GSHPx) is a critical antioxidant enzyme that removes H(2)O(2) in both the cytosol and mitochondia. We hypothesized that the overexpression of GSHPx gene could attenuate left ventricular (LV) remodeling in diabetes mellitus (DM). We induced DM by injection of streptozotocin (160 mg/kg ip) in male GSHPx transgenic mice (TG+DM) and nontransgenic wildtype littermates (WT+DM). GSHPx activity was higher in the hearts of TG mice compared with WT mice, with no significant changes in other antioxidant enzymes. LV thiobarbituric acid-reactive substances measured in TG+DM at 8 wk were significantly lower than those in WT+DM (58 +/- 3 vs. 71 +/- 5 nmol/g, P < 0.05). Heart rate and aortic blood pressure were comparable between groups. Systolic function was preserved normal in WT+DM and TG+DM mice. In contrast, diastolic function was impaired in WT+DM and was improved in TG+DM as assessed by the deceleration time of peak velocity of transmitral diastolic flow and the time needed for relaxation of 50% maximal LV pressure to baseline value (tau; 13.5 +/- 1.2 vs. 8.9 +/- 0.7 ms, P < 0.01). The TG+DM values were comparable with those of WT+Control (tau; 7.8 +/- 0.2 ms). Improvement of LV diastolic function was accompanied by the attenuation of myocyte hypertrophy, interstitial fibrosis, and apoptosis. Overexpression of GSHPx gene ameliorated LV remodeling and diastolic dysfunction in DM. Therapies designed to interfere with oxidative stress might be beneficial to prevent cardiac abnormalities in DM.     

Wing base morphology of Aetalionidae (Hemiptera: Cicadomorpha) and its phylogenetic implications

The Aetalionidae is a small family belonging to the treehopper superfamily Membracoidea (Hemiptera: Cicadomorpha). Although the wing‐base morphology of Cicadomorpha was examined in detail recently, the wing base of this family has not been investigated to date. We examined morphology of the wing‐base structure of Aetalionidae. Using the characters selected from the wing base, we inferred the phylogenetic placement of this family and confirmed that it belongs to the superfamily Membracoidea and is likely a sister group of the Membracidae.     

Inhibition of D-serine accumulation in the Xenopus oocyte by expression of the rat ortholog of human 3'-phosphoadenosine 5'-phosphosulfate transporter gene isolated from the neocortex as D-serine modulator-1

D-serine in mammalian brains has been suggested to be an endogenous co-agonist of the NMDA-type glutamate receptor. We have explored the molecules regulating D-serine uptake and release from the rat neocortex cDNA library using a Xenopus oocyte expression system, and isolated a cDNA clone designated as dsm-1 (D-serine modulator-1) encoding a protein that reduces the accumulation of D-serine to the oocyte. dsm-1 is the rat orthologue of the human 3'-phosphoadenosine 5'-phosphosulfate transporter 1 (PAPST1) gene. The hydropathy analysis of the deduced amino acid sequence of the Dsm-1 protein predicts the 10 transmembrane domains with a long hydrophobic stretch in the C-terminal like some amino acid transporters. The dsm-1 mRNA is predominantly expressed in the forebrain areas that are enriched with D-serine and NMDA receptors, and in the liver. The transient expression of dsm-1 in COS-7 cells demonstrates a partially Golgi apparatus-related punctuate distribution throughout the cytoplasm with a concentration near the nucleus. dsm-1-expressing oocytes diminishes the sodium-dependent and -independent accumulation of D-serine and the basal levels of the intrinsic D-serine and increases the rate of release of the pre-loaded D-serine. These findings indicate that dsm-1 may, at least in part, be involved in the D-serine translocation across the vesicular or plasma membranes in the brain, and thereby control the extra- and intracellular contents of D-serine.     

The solution structure of horseshoe crab antimicrobial peptide tachystatin B with an inhibitory cystine-knot motif.

Tachystatin B is an antimicrobial and a chitin-binding peptide isolated from the Japanese horseshoe crab (Tachypleus tridentatus) consisting of two isopeptides called tachystatin B1 and B2. We have determined their solution structures using NMR experiments and distance geometry calculations. The 20 best converged structures of tachystatin B1 and B2 exhibited root mean square deviations of 0.46 and 0.49 A, respectively, for the backbone atoms in Cys(4)-Arg(40). Both structures have identical conformations, and they contain a short antiparallel beta-sheet with an inhibitory cystine-knot (ICK) motif that is distributed widely in the antagonists for voltage-gated ion channels, although tachystatin B does not have neurotoxic activity. The structural homology search provided several peptides with structures similar to that of tachystatin B. However, most of them have the advanced functions such as insecticidal activity, suggesting that tachystatin B may be a kind of ancestor of antimicrobial peptide in the molecular evolutionary history. Tachystatin B also displays a significant structural similarity to tachystatin A, which is member of the tachystatin family. The structural comparison of both tachystatins indicated that Tyr(14) and Arg(17) in the long loop between the first and second strands might be the essential residues for binding to chitin.