Resolution of 2,2-diphenyl-1,3-dioxolane-4-methanol via Rhizopus sp. lipase-catalyzed enantioselective transesterification with vinyl butanoate

2,2-Diphenyl-1,3-dioxolane-4-methanol was resolved via Rhizopus sp. lipase-catalyzed enantioselective transesterification with vinyl butanoate in isopropyl ether (E=23). A gram-scale resolution resulted in the production of the (R)-alcohol with 95% e.e. in 33% yield based on racemate.     

Simple high-performance liquid chromatography determination of ampicillin in human serum using solid-phase extraction disk cartridges

A simple and reproducible method for the analysis of ampicillin in human serum was developed. Serum samples were extracted using solid-phase extraction disk cartridges containing a sorbent of styrene divinyl/benzene. Extracts were separated by reversed-phase C₁₈ high-performance liquid chromatography with UV detection at 220 nm. The mobile phase consisted of acetonitrile–10 mM NaH₂PO₄ (6.5:93.5, v/v). Using this extraction procedure, recovery from serum was 98.4±5.6%. The quantitation limit was 0.19 μg/ml using 0.5 ml of serum. The calibration curves from 0.19 to 9.41 μg/ml were linear with correlation coefficients of 0.999. This method is suitable for therapeutic drug monitoring of ampicillin (ABPC) after oral administration of lenampicillin hydrochloride.     

Salt water promotes hypertension in Dahl-S rats.

Hypertension was induced in Dahl-salt-sensitive (Dahl-S) rats by administering salt in drinking water. Control rats receiving tap water did not show a significant change in blood pressure or abnormalities in the kidney. Rats receiving 0.5% NaCl solution developed moderate hypertension and renal lesions. Rats receiving 1.0% NaCl solution showed prominent and increasing hypertension and severe renal damage. This method of salt administration should be simpler than administration in the diet as a means of promoting renal hypertension. The lower concentration salt water caused chronic mild hypertension in Dahl-S rats, and may serve as a useful model for progressive hypertension.     

Analysis with flow cytometry of green fluorescent protein expression in leukemic cells.

BACKGROUND: The measurement of DNA content with propidium iodide (PI) in cells transfected with expression vectors encoding the green fluorescent protein (GFP) is a useful tool in studying a variety of biological functions of proteins within cells. The purpose of this study was to determine conditions of formaldehyde fixation that permit intracellular GFP fluorescence and adequate DNA histograms to be generated following transient transfection of cells with a GFP-encoding plasmid. Cell cycle analysis was also performed in GFP-positive cells. METHODS: The murine myeloid leukemic cell line, 32Dcl3, was used as the model system. Cells were transfected with a GFP-encoding plasmid (pEGFPC1). Following fixation in different formaldehyde concentrations and permeabilization with 70% ethanol, cells were stained with PI and analyzed by flow cytometry for GFP fluorescence and DNA content. Transfected cells were also analyzed for GFP fluorescence and DNA content following release from nocodazole block. RESULTS: Fixing cells in 0.51-1.75% formaldehyde concentrations prior to ethanol permeabilization resulted in 14-19% of transfected cells being GFP-positive, with acceptable coefficients of variation on the G(1) peak of DNA histograms. Analysis of cells synchronized to and released from the G(2)-M phase by nocodazole suggested that GFP-positive cells, when compared to GFP-negative cells, did not appear to progress out of G(2)-M following release from nocodazole block. Simultaneous detection of GFP fluorescence and DNA content by PI staining is possible following transient transfection of cells with a single expression vector encoding GFP. Our results demonstrate that GFP expression can be detected, using flow cytometry to perform cell cycle analysis in murine leukemic cells.     

Purification and characterization of a novel enzyme, L-threo-3-hydroxyaspartate dehydratase, from Pseudomonas sp. T62

L-threo-3-Hydroxyaspartate dehydratase (L-threo-3-hydroxyaspartate hydro-lyase), which exhibited specificity for L-threo-3-hydroxyaspartate (K(m)=0.74 mM, V(max)=37.5 micromol min(-1) (mg protein)(-1)) but not for D-threo or D, L-erythro-3-hydroxyaspartate, was purified from a cell-free extract of Pseudomonas sp. T62. The activity of the enzyme was inhibited by hydroxylamine and EDTA, which suggests that pyridoxal 5'-phosphate and divalent cations participate in the enzyme reaction. The NH(2)-terminal amino acid sequence showed significant similarity to the Saccharomyces cerevisiae YKL218c gene product, a hypothetical threonine dehydratase. However, the purified enzyme showed no threonine dehydratase activity.     

Flavones in Green Tea

Nineteen flavones were newly found in green tea infusion. Four pigments were isolated, and one of them was identified as vitexin (C-glycosyl flavone). As the remained pigments were obtained only in small quantities, their properties were studied spectrophotometrically. Similarity of their UV spectra and color reactions suggested that all of them have the same skeleton as 5, 7, 4′-trihydroxyflavone (apigenin). The major one has high water solubility and deep greenish yellow color in aqueous solution, so that it may be the important constituents related to the color of green tea infusion.     

Oxidation of O-Alkyl-O-(subst. phenyl) phenylphosphonothioates

It has been found that exocellular α-amylase could be fixed to mycelia of Aspergillus oryzae at an acidic pH region and fixed α-amylase was released reversely at an alkaline pH region. The fixation has more remarkably been observed in mycelia obtained from a phosphate deficient medium where endocellular accumulation of a-amylase occurs more easily than in an ordinary mycelia which secrete a large amount of α-amylase into medium. Bound form of α-amylase was more resistant to low pH and less active than the free form. The results appear to support the previous suggestion that a large quantity of endocellular α-amylase might be located on mycelial surface of the mold.