Reduction of vanadium(V) to vanadium(IV) by NADPH, and vanadium(IV) to vanadium(III) by cysteine methyl ester in the presence of biologically relevant ligands

To better understand the mechanism of vanadium reduction in ascidians, we examined the reduction of vanadium(V) to vanadium(IV) by NADPH and the reduction of vanadium(IV) to vanadium(III) by L-cysteine methyl ester (CysME). UV-vis and electron paramagnetic resonance spectroscopic studies indicated that in the presence of several biologically relevant ligands vanadium(V) and vanadium(IV) were reduced by NADPH and CysME, respectively. Specifically, NADPH directly reduced vanadium(V) to vanadium(IV) with the assistance of ligands that have a formation constant with vanadium(IV) of greater than 7. Also, glycylhistidine and glycylaspartic acid were found to assist the reduction of vanadium(IV) to vanadium(III) by CysME.     

DNA homology of surface protein antigen A gene in mutans streptococci

1. A recombinant plasmid, pYA724, containing an 8.45 kb DNA fragment encoding surface protein antigen A (spaA) from Streptococcus sobrinus 6715 was used to examine the DNA homology of the spaA gene with chromosomal DNA of various mutans streptococci strains. 2. Restriction endonuclease BamHI-digested pYA724 DNA was radio-labeled by nick-translation, and a DNA-DNA hybridization experiment was carried out. pYA724 DNA hybridized with chromosomal DNA of serotypes a, c, d, e, f and g strains, but not with b by dot DNA-hybridization and Southern blot DNA hybridization. 3. Chromosomal DNAs were isolated from several serotype c Streptococcus mutans strains, digested with BamHI, and analyzed by Southern blot DNA hybridization. pYA724 DNA hybridized with different sizes and numbers of BamHI-digested DNA fragments of the chromosomal DNAs. 4. These data indicated that all mutans streptococci strains except serotype b have DNA homologous with the spaA gene, although within the same serotype strain the spaA gene has a diversity of arrangement within the chromosome.     

Free arachidonic acid source for PGE2 and TXB2 production in guinea pig peritoneal macrophages exposed to insoluble glucan from Streptococcus mutans

1. Macrophages are an important source of the lipid mediators arachidonic acid (AA) and its metabolites that are produced during inflammation. 2. Previously, we reported that insoluble glucans from Streptococcus mutans in dental plaque could induce macrophages to secrete PGE2 and TXB2. 3. Studies were undertaken to identify the phospholipid substrates that can serve as a source of AA in macrophages exposed to the insoluble glucan. 4. When macrophage cell prelabelled with [3H]AA, stimulation with insoluble glucan resulted in a loss of label mainly from phosphatidylcholine (PC) and phosphatidylinositol (PI). 5. In addition, the PC-, and PI-specific phospholipase A2-mediated mechanisms for AA release may be activated in guinea peritoneal macrophages exposed to the insoluble glucan from S. mutans.     

Determination of erythromycin, clarithromycin, roxithromycin, and azithromycin in plasma by high-performance liquid chromatography with amperometric detection

In this study, a high-performance liquid chromatographic method was developed for the quantitative determination of erythromycin (EM), roxithromycin (RXM), and azithromycin (AZM) in rat plasma with amperometric detection under a standardized common condition using clarithromycin (CAM) as an internal standard. This method was also proved to be applicable for the determination of CAM by employing RXM as an internal standard. Each drug was extracted from 150 μl of plasma sample spiked with internal standard under an alkaline condition with tert.-butyl methyl ether. The detector cell potential for the oxidation of the drugs was set at +950 mV. The linearity of the calibration curves were preserved over the concentration ranges of 0.1–10 μg/ml for EM and RXM, and 0.03–3.0 μg/ml for CAM and AZM. Coefficients of variation and relative error were less than 9% and ±7%, respectively. The analytical method presented here was proved to be useful for the investigation of the pharmacokinetic characteristics of EM, CAM, RXM, and AZM in rats.     

Expression of periostin in patients with non-small cell lung cancer: correlation with angiogenesis and lymphangiogenesis

The aim of this study was to evaluate periostin expression measured immunohistochemically in patients with non-small cell lung cancer (NSCLC) and to determine its association with clinical features, prognosis, angiogenesis, and lymphangiogenesis. We investigated periostin expression in a series of 88 patients with NSCLC. We also determined whether expression of periostin correlated with microvessel density and lymphatic microvessel density. Periostin was expressed in 42% of 88 patients. Its expression was significantly correlated with tumor size, lymph node metastasis, disease stage, and lymphatic invasion (p=0.0128, 0.0015, 0.0310 and 0.0273, respectively). There also was a significant relation between periostin expression and microvessel density and lymphatic microvessel density (all p<0.0001). Five-year survival rates were better in patients with negative periostin expression than in those with positive periostin expression (p=0.0044). Periostin expression was not significant in a multivariate additive model. Our findings show that periostin correlates with increased tumor progression and a worse prognosis in NSCLC, as well as with angiogenesis and lymphangiogenesis.     

Endo-1,4-{beta}-Glucanase in the Cell Wall of Stems of Auxin-Treated Pea Seedlings

Endo-1,4-ß-glucanase induced by treatment of pea seedlingswith 2,4-D was extracted from a preparation of the walls ofepicotyl cells. The ß-glucanase was purified by chromatographyon DEAE-cellulose, affinity chromatography on Con A-Sepharoseand SDS-polyacrylamide gel electrophoresis (SDS-PAGE). The activityof ß-glucanase was retained after removal of SDS andextraction from polyacrylamide gels. The band of a protein (46kDa), that corresponded to the activity of endo-1,4-ß-glucanase,was injected directly into mice for preparation of antiserumand the protein was also subjected to amino acid sequencingafter blotting onto a membrane. Western blot analysis showedthat the antiserum obtained bound to a 46-kDa polypeptide andrecognized endo-1,4-ß-glucanase. The N-terminal sequenceof the 46-kDa polypeptide revealed some homology to abscissionendo-1,4-ß-glucanases of bean and avocado fruit. (Received September 29, 1993; Accepted January 20, 1994)     

Moss PPR-SMR protein PpPPR_64 influences the expression of a psaA-psaB-rps14 gene cluster and processing of the 23S–4.5S rRNA precursor in chloroplasts

Plant Molecular Biology - Moss PPR-SMR protein PpPPR_64 is a pTAC2 homolog but is functionally distinct from pTAC2. PpPPR_64 is required for psaA gene expression and its function may have evolved...     

Ecological balance between ciliate plankton and its prey candidates,pico- and nanoplankton,in the East China Sea

Standing stocks of ciliate plankton and its prey candidates, both picoplankton and nanoplankton, were investigated in spring in the East China Sea. The former was 1.36 × 10⁵–1.54 × 10⁸ μm³ l⁻¹ in biovolume, and the latter was 5.33 × 10⁶–1.11 × 10⁸ μm³ l⁻¹. The biovolume ratio of ciliate plankton to prey candidates ranged from 1.31 × 10⁻² to 2.00 × 10⁰; it was larger in abundant prey conditions and smaller in sparse preys. Making some plausible assumptions about physiological activity on both organisms, every ratio meet the quantitative restriction that prey production should be equal to or larger than ciliate consumption. However, prey candidates would be so sparsely distributed that ciliate plankton could not capture sufficient prey organisms in its random filter-feeding manner. Even though planktonic ciliates must have some extraordinary mechanisms to capture preys efficiently, this quantitative imbalance might be one of the reasons for decreasing ciliate/prey ratio in sparse prey conditions. Handling editor: K. Martens     

The Oligosaccharide Units of the Xyloglucans in the Cell Walls of Bulbs of Onion, Garlic and their Hybrid

Xyloglucans were isolated from the 24% KOH-soluble fractionof the cell walls of bulbs of onion (Allium cepa), garlic (Alliumsativum) and their hybrid. The polysaccharides yielded singlepeaks upon gel filtration with average moleular weights of 65,000for onion, 55,000 for garlic and 82,000 for the hybrid. Compositionalanalysis of the oligosaccharide units after digestion with anendo-1,4-ß-glucanase from Streptomyces indicated thatthe polysaccharides were constructed of four kinds of repeatingoligosaccharide unit, namely, a decasaccharide (glucose/xylose/galactose/fucose,4 : 3 : 2 : 1), a nonasaccharide (glucose/xylose/galactose/fucose,4 : 3 : 1 : 1), an octasaccharide (glucose/xylose/galactose,4 : 3 : 1 ) , and a heptasaccharide (glucose/xylose, 4 : 3).The xyloglucan from the hybrid contained highly fucosylatedunits that resembled those from onion rather than from garlic.The analysis also revealed that the xyloglucans from Alliumspecies contain highly substituted xylosyl residues with fucosyl-galactosylresidues, suggesting that these monocotyledonous plants resembledicotyledons in the structural features of their xyloglucans. (Received November 1, 1993; Accepted June 16, 1994)