Effects of 32-oxygenated lanosterol derivatives on 3-hydroxy-3-methylglutaryl coenzyme A reductase activity and cholesterol biosynthesis from 24,25-dihydrolanosterol.

The effects of 32-oxygenated lanosterol derivatives on 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase activity and cholesterol biosynthesis from [24,25-3H]24,25-dihydrolanosterol were studied. Among the derivatives, 3 beta-hydroxylanost-7-en-32-oic acid was the most active in depressing HMG-CoA reductase activity (IC50: 0.7 microM) and cholesterol biosynthesis (IC50: 0.4 microM) from 24,25-dihydrolanosterol.     

Effect of pressure on electrophoretic mobility of polystyrene latex particles

A capillary electrophoresis system that can apply arbitrary helium gas pressures at both inlet and outlet reservoirs was constructed. The system was used to investigate the effect of pressure on electrophoretic behavior of polystyrene latex particles. The electrophoretic mobility of latex particles was increased with the application of pressure (< 3.0 kgf/cm2). The shrinkage of particle diameter under pressurization was observed using a microscope, however, the magnitude of shrinkage was not enough to explain the increase in electrophoretic mobility. Therefore, the application of pressure might increase the electric charge of the latex particle. Since methanol inhibited the enhancement in the electrophoretic mobility of the latex particles, water might play an important role in increasing mobility.     

Transformation of pyrazolo[4,3-c]isothiazoles into 3,4-disubstituted 1,2-isothiazoles

Pyrazolo[4,3-c]isothiazoles 4 and 5 were synthesized by the reaction of 4-aminoantipyrine 1 with thionyl chloride. Treatment of 4 or 5 with alkylamines underwent pyrazole ring opening to afford 3,4-disubstituted 1,2-isothiazoles 8a-f .     

Effect of meso-hexestrol, a synthetic estrogen, on S-tubulin

We have reported that meso-hexestrol, a synthetic estrogen, inhibits microtubule assembly and induces microtubule proteins into twisted ribbon structures. On the other hand, Serrano et al. proved that S-tubulin, which lacks the C-terminal moiety of tubulin subunits, assembles into sheet structures in the absence of microtubule-associated proteins (MAPs). In the present investigation, we attempted to clarify whether meso-hexestrol could induce the ribbon structure from S-tubulin. meso-Hexestrol delayed the initiation of polymerization of S-tubulin into sheet structures in a dose-dependent manner below 50 microM. But the effect of meso-hexestrol on S-tubulin was reduced in the presence of either tau or microtubule-associated protein 2 (MAP2) in a MAPs-concentration-dependent manner. At concentrations higher than 100 microM, meso-hexestrol inhibited the polymerization of S-tubulin into sheet structures, without forming ribbon structures. The present results may indicate that moso-hexestrol interacts with S-tubulin, and its interaction is affected by MAPs.     

Benzofuran derivatives. Part 4 , synthesis of benzofurans and 2,3,4,5-tetrahydro-1-benzoxepin-3,5-diones

By treatment of ethyl 4- or 5-substituted 2-acetylphenoxyacetates 1 with potassium hydroxide in dry dioxane, benzofurans 2–7 and 2,3,4,5-tetrahydro-1-benzoxepin-3,5-diones 8 were obtained. The relative yields of benzofurans 2–7 and 2,3,4,5-tetrahydro-1-benzoxepin-3,5-diones 8 varied with the types of 4- or 5-substituents. The electron-donating 4-methoxyl group favored the formation of benzoxepins. On the other hand, electron-withdrawing substituents such as the 4-nitro group favored the formation of benzofurans. When esters 1 were treated with sodium amide, 2,3-dihydrobenzofurans 2 were obtained exclusively regardless of 4- or 5-substituents.     

The sennoside constituents of rhei rhizoma and sennae folium as inhibitors of serum monoamine oxidase

Four (in total) compounds with inhibitory effects on the activity of bovine serum monoamine oxidase were isolated from the methanol-water extracts of Rhei Rhizoma (Daiou) and Sennae Folium (Senna), and identified as sennosides A, B, E and F. Among them, sennosides A and B were obtained from both Rhei Rhizoma and Sennae Folium, while sennosides E and F were detected only in the former. The 50% inhibitory concentrations of the four sennosides were 17, 9, 24 and 13 microM, respectively, and the type of inhibition by seenosides A and B with respect to allylamine as the substrate was non-competitive.     

Ring transformation of 5-amino (or acylamino)-6-hydroxy (or benzoyloxy)methylpyrimidin-4(3H)-ones into 1H-imidazoles

Treatment of 5-acylamino-6-hydroxy (or benzoyloxy)methyl-3-phenylpyrimidin-4(3H)-one 5,10 with 5% aqueous sodium hydroxide in ethanol gave 2-alkyl-5-hydroxymethyl-4-phenylcarbamoyl-1H-imidazoles 7,11 . Oxidation of 5-amino-6-benzoyloxymethyl-3-phenylpyrimidin-4(3H)-one 9 in the presence of copper( II ) chloride in alcohol gave 2-alkoxy-5-alkoxymethyl-4-phenylcarbamoyl-1H-imidazoles 12a,b accompanied by 5-amino-6-alkoxymethyl-3-phenylpyrimidin-4(3H)-ones 13a,b.     

An autolytic substance in a freshwater cyanobacterium Phormidium tenue

An autolytic substance in an axenic cyanobacterium, Phormidium tenue, was identified as a mixture of fatty acids, by use of cultured cells in the laboratory. Among them, linoleic acid and linolenic acid were potent growth inhibitors.     

Lactose hydrolysis and beta-galactosidase activity in sonicated fermentation with Lactobacillus strains

Milk fermentation with four Lactobacillus strains, including L. delbrueckii subsp. bulgaricus B-5b, L. helveticus LH-17, L. delbrueckii subsp. lactis SBT-2080 and L. acidophilus SBT-2068, was carried out under sonicated conditions. Under continuous sonication, viable cell count decreased or grew less than in conventional fermentation, but it increased considerably in static incubation after sonication. Sonication caused beta-galactosidase release from lactic acid bacteria cells to the culture medium, thus resulting in higher total beta-galactosidase activity. However, lactose hydrolysis was enhanced only when beta-alactosidase was effectively released. With L. delbrueckii subsp. bulgaricus B-5b and L. helveticus LH-17. the degrees of lactose hydrolysis achieved were about 75% which is much higher than those in conventional fermentation (below 40%). Results presented here showed that a high viable cell count and a high degree of lactose hydrolysis could be simultaneously achieved by a suitable sonication method.     

A Rapid-Scanning Spectrometer with Wavelength Synchronization by a Laser Rotary Encoder for Versatile Applications to Atomic Emission Spectrometry

A rapid-scanning spectrometer was developed for versatile use in atomic emission spectroscopy. The sine bar was removed and a laser rotary encoder was fitted to the grating shaft for wavelength synchronization. The pulses produced by the encoder when the grating shaft was driven back and forth in sector movements were counted to detect the grating angle and the wavelength. The wavelength accuracy and precision obtained were ±0.26 and ±0.013 nm, respectively. The maximum scanning speed was limited below 4000 nm/s by a malfunction in wavelength synchronization. The rapid-scanning spectrometer was successfully used for multielement determinations, correction of background emission, and characterization of an inductively coupled plasma.