Preparation of 2-deoxy-2-C-p-tolylsulfonyl-beta-D-glucopyranosyl p-tolylsulfones having non-chair conformation and their elimination reactions

When the title sulfones, which have non-chair conformations, were stirred with silica gel, elimination of sulfinic acid occurred to give a 1-enitol derivative, if the hydroxyl group at C-6 was protected, whereas such an elimination did not proceed if the hydroxy group was free.     

Triacylglycerol/phospholipid molecular species profiling of fatty livers and regenerated non-fatty livers in cystathionine beta-synthase-deficient mice, an animal model for homocysteinemia/homocystinuria

Fatty liver is one of the typical manifestations in homocysteinemia/homocystinuria patients and their genetic animal model, mice lacking cystathionine ??-synthase (Cbs ^?/?). The vast majority of Cbs ^?/? die within 4?weeks after birth via yet unknown mechanisms, whereas a small portion survive to adulthood, escaping fatty degeneration of the liver during lactation periods, through regeneration. To investigate the molecular basis of such fatty changes, we analyzed lipid components in fatty livers of 2-week-old Cbs ^?/? and regenerated non-fatty livers of 8-week-old Cbs ^?/? survivors using a chip-based nanoESI (electrospray ionization)-MS system, which allows quantitative detection of triacylglycerol/phospholipid molecular species. Hepatic levels of all major triacylglycerol species were much higher in Cbs ^?/? than in wild-type mice at 2?weeks, although not at 8?weeks. Levels of some phospholipid species were either up- or downregulated in 2-week-old Cbs ^?/?; e.g. saturated (16:0 and 18:0) or mono-unsaturated (16:1 and 18:1) fatty acids-containing phosphatidylcholine/phosphatidylethanolamine species were upregulated, while poly-unsaturated fatty acids-containing phosphatidylcholine (18:2?C18:2 and 18:2?C20:5), phosphatidylethanolamine (18:1?C20:4), and phosphatidylinositol (18:0?C20:4) were downregulated. Capillary electrophoresis-MS analysis identified high-level accumulation of S-adenosylmethionine and S-adenosylhomocysteine in fatty livers of 2-week-old Cbs ^?/? but much less in non-fatty livers of 8-week-old Cbs ^?/?. Although hepatic S-adenosylmethionine/S-adenosylhomocysteine ratios were comparable between 2-week-old Cbs ^?/? and wild-type, global protein arginine methylation was disturbed in fatty livers of Cbs ^?/?. Our results suggest that cellular signaling mediated by altered phospholipid contents might be involved in pathogenesis of fatty liver in Cbs ^?/?C.     

Antiviral activities of diarylheptanoids isolated from Alpinia officinarum against respiratory syncytial virus, poliovirus, measles virus, and herpes simplex virus type 1 in vitro

Alpinia officinarum has been used as a folk medicine and contains diarylheptanoids that have various biological activities. However, their antiviral activities are less elucidated. We examined the antiviral activities of nine diarylheptanoids isolated from A. officinarum against respiratory syncytial virus (RSV), poliovirus, measles virus, and herpes simplex virus type 1 (HSV-1) using a plaque reduction assay. The 50% inhibitory concentrations of seven of the nine diarylheptanoids for RSV were moderately but significantly lower than their 50% cytotoxic concentrations, as determined by a trypan blue exclusion assay. Four diarylheptanoids with anti-RSV activity also showed anti-poliovirus and anti-measles virus activities and three of the four exhibited anti-HSV-1 activity. Thus, seven of the nine diarylheptanoids examined exhibited potential antiviral activity against RSV, and most of the diarylheptanoids with anti-RSV activity, including two diarylheptanoids without anti-RSV activity, were effective against poliovirus, measles virus, and/or HSV-1 in vitro. Diarylheptanoids were suggested to have a broad spectrum of antiviral activity.     

Peak spreading in linear gradient elution chromatography with a thin monolithic disk

The peak spreading of DNAs of various sizes [12-mer, 20-mer, 50-mer and 95-mer poly(T)] in linear gradient elution (LGE) chromatography with a thin monolithic disk was investigated by using our method developed for determining HETP in LGE. Electrostatic interaction-based chromatography mode (ion-exchange chromatography, IEC) was used. Polymer-based monolithic disks of two different sizes (12 mm diameter, 3mm thickness and 0.34 mL; 5.2 mm diameter, 4.95 mm thickness and 0.105 mL) having anion-exchange groups were employed. For comparison, a 15-μm porous bead IEC column (Resource Q, 6.4mm diameter, 30 mm height and 0.97 mL) was also used. The peak width did not change with the flow velocity for the monolithic disks where as it became wider with increasing velocity. For the monolithic disks the peak width normalized with the column bed volume was well-correlated with the distribution coefficient at the peak position K(R). HETP values were constant (ca. 0.003-0.005 cm) when K(R)>5. Much higher HETP values which are flow-rate dependent were obtained for the porous bead chromatography. It is possible to obtain 50-100 plates for the 3mm monolithic disk. This results in very sharp elution peaks (standard deviation/bed volume=0.15) even for stepwise elution chromatography, where the peak width is similar to that for LGE of a very steep gradient slope.     

Ag(I) ion mediated formation of a C-A mispair by DNA polymerases

Silver turns up the A-C: In the presence of Ag(I) ions, a DNA polymerase incorporated deoxyadenosine (from dATP) at the site opposite cytosine in the template strand to afford the full-length product (see scheme), meaning that DNA polymerases prefer a C-Ag(I)-A base pair to the more thermodynamically stable C-Ag(I)-C base pair.     

Gaining insight into the inhibition of glycoside hydrolase family 20 exo-β-N-acetylhexosaminidases using a structural approach

One useful methodology that has been used to give insight into how chemically synthesized inhibitors bind to enzymes and the reasons underlying their potency is crystallographic studies of inhibitor-enzyme complexes. Presented here is the X-ray structural analysis of a representative family 20 exo-β-N-acetylhexosaminidase in complex with various known classes of inhibitor of these types of enzymes, which highlights how different inhibitor classes can inhibit the same enzyme. This study will aid in the future development of inhibitors of not only exo-β-N-acetylhexosaminidases but also other types of glycoside hydrolases.     

An acyclic phane receptor with a pair of disulfonaphthalene arms recognizing 2,3-trans-gallate-type catechins in water

In order to develop a receptor molecule for recognizing differences in catechin structures, complexation between catechins and a water-soluble acyclic phane composed of an isophthalate and two aminodisulfonaphthalenes was investigated with ¹H NMR spectroscopy. The phane receptor formed 1:1 complexes with the catechins and showed preferential binding ability for the 2,3-trans-gallate-type catechin. The binding studies demonstrated the length of naphthalene framework required to form a hydrophobic environment for the complexation.     

Spectral analysis of scattered light from flowers’ petals

A new method was developed for studying absorption characteristics of opaque samples based on the light scattering spectroscopy. Measurements were made in white, red and violet petals of Petunia hybrida, and gave the absorption spectra in a non-destructive manner without damaging the cell structures of the petal. The red petal has absorption peak at 550 nm and the violet has three absorption peaks: at 450, 670, and 550 nm. The results were discussed in correlation with the microscopic cell structures of the petal observed with optical microscope and transmission electron microscopy (TEM). Only the cells placed in the surface have the pigments giving the color of the petal.     

Stereoselective synthesis of either (E)- or (Z)-silyl enol ether from the same acyclic α,β-unsaturated ketone using cationic rhodium complex-catalyzed 1,4-hydrosilylation

The stereoselective synthesis of either (E)- or (Z)-silyl enol ether from the same acyclic α,β-unsaturated ketone is reported. Highly (Z)-selective conditions were the use of [Rh(cod)₂]BF₄/DPPE at room temperature with no solvent, whereas (E)-selective conditions were the use of [Rh(cod)₂]BF₄/P(1-Nap)₃ (1-Nap = 1-naphthyl) under refluxing dichloromethane.