The catalysis of the Ruff oxidative degradation of aldonic acids by titanium‐containing zeolites

Ti‐BEA and Ti‐FAU, obtained by post‐synthesis treatment, and TS‐1, obtained by direct hydrothermal synthesis, have been tested as catalysts for the Ruff oxidative degradation of calcium d‐gluconate to d‐arabinose using diluted hydrogen peroxide as oxidant. Only large‐pore zeolites Ti‐BEA and Ti‐FAU were found to be active. It was shown, in particular, that a very rapid leaching of titanium occurred and that the titanium species present in the solution were responsible for the catalytic activity observed. This revised version was published online in August 2006 with corrections to the Cover Date.     

The role of endothelin in regulation of vascular tone in physiology and pathology

JC virus (JCV) with an archetypal regulatory region (archetype) has been cloned from urines of a healthy individual. It has been suggested that the regulatory region of prototype JC virus (PML type) isolated from brain of PML patient was derived from that of the archetype by deletion and duplication. Biological characteristics of archetypal JCV, however, have not been fully studied. In the present study we examined the infectivity of archetypal JCV (CY), PML-type JCV (Mad-1) and Chimera JCV (Mad-1/CR-CY), in which the regulatory region is composed of CY and the other region Mad-1. DNAs from the three JCV types were transfected into COS-7 (monkey kidney cells transformed with SV40 T) and IMR-32 (human neuroblastoma cell). COS-7 was permissive for all three types, but IMR-32 was only infected with Mad-1. Infected DNAs were confirmed by Southern blotting, and the constancy of the regulatory regions before and after transmission was verified by DNA sequencing. The results showed that the viral regulatory region was related to viral cell tropism and that PML type regulatory region would be necessary for IMR-32 to propagate. The fact that COS-7 was susceptible for all three types may be explained by the function of SV40 T protein. In addition, we first succeeded in the propagation of CY in COS-7, which would provide a useful system to analyze the mechanism of persistent infection of archetypal JCV.     

Combined GC/MS analytical procedure for the characterization of glycerolipid, waxy, resinous, and proteinaceous materials in a unique paint microsample

A novel GC/MS analytical procedure for the identification of lipids, waxes, proteins, and resinous materials in the same microsample from painted works of art has been optimized. It is based on a sample multistep chemical pretreatment (solvent extractions and microwave-assisted chemolysis) that is able to separate the various organic components into different fractions, which are suitably treated and derivatized before analysis. In particular, the procedure allows the complete saponification of wax esters and the completeness of the Cannizzaro type reaction of shellac acids in conditions that are suitable also for glycerides saponification. The method was tested on reference materials for the identification of proteinaceous binders (egg, collagen, casein) on the basis of the quantitative determination of the amino acid profile and the identification of glycerolipids (linseed oil, poppy seed oil, walnut oil, and egg), plant resins (Pinaceae resins, sandarac, mastic, and dammar), animal resins (shellac), tars or pitches, and natural waxes (beeswax, carnauba wax) on the basis of the determination of fatty acid, alcohol, and hydrocarbon profiles and of significant terpenic molecular markers. The procedure was applied to the characterization of three old paint microsamples. Animal glue, egg, linseed oil, beeswax, Pinaceae resin, dammar, and shellac were the identified materials found in mixtures and recognized as original and/or restoration substances.     

In Vivo Performance and Structural Relaxation of Biodegradable Bone Implants Made from Mg?Zn?Ca Bulk Metallic Glasses

A study of Mg‐based bulk metallic glasses (BMGs) as biodegradable bone implants is presented. The implantation site can affect performance, so the BMGs were evaluated in vivo in rat femurs using µ‐CT scans at various times for more than 90 days. Estimates of H₂ evolution correlate well with previous in vitro studies and bone–implant contact is similar to that for Ti pins. One potential drawback of Mg‐based BMGs in this application is embrittlement due to structural relaxation. Here, relaxation at 20 and 37 °C is examined, and an increase in the characteristic relaxation time, from 10 to 30 days at 20 °C, is observed as Zn increases from 29 to 32 at.%, correlating with dramatically reduced hydrogen evolution.     

The first dairy product exclusively fermented by Propionibacterium freudenreichii: A new vector to study probiotic potentialities in vivo

Dairy propionibacteria display probiotic properties which require high populations of live and metabolically active propionibacteria in the colon. In this context, the probiotic vector determines probiotic efficiency. Fermented dairy products protect propionibacteria against digestive stresses and generally contain a complex mixture of lactic and propionic acid bacteria. This does not allow the identification of dairy propionibacteria specific beneficial effects. The aim of this study was to develop a dairy product exclusively fermented by dairy propionibacteria. As they grow poorly in milk, we determined their nutritional requirements concerning carbon and nitrogen by supplementing milk ultrafiltrate (UF) with different concentrations of lactate and casein hydrolysate. Milk or UF supplemented with 50 mM lactate and 5 g L⁻¹ casein hydrolysate allowed growth of all dairy propionibacteria studied. In these new fermented dairy products, dairy propionibacteria remained viable and stress-tolerant in vitro during minimum 15 days at 4 °C. The efficiency of milk fermented by the most tolerant Propionibacterium freudenreichii strain was evaluated in piglets. Viability and SCFA content in the colon evidenced survival and metabolic activity of P. freudenreichii. This work results in the design of a new food grade vector, which will allow preclinical and clinical trials.     

A blue can conceal another! Noninvasive multispectroscopic analyses of mixtures of indigo and Prussian blue

Blue colors were sparsely used in the first colored Japanese ukiyo-e prints but became predominant during the 19th century, mainly due to the integration of the synthetic Prussian blue in the palette of the printers around 1830. For a long time, researchers have assumed that the traditional Japanese organic blue colorants such as indigo were substituted by cheaper Prussian blue. Some analytical studies conducted on such artworks showed evidence of the common use of indigo and Prussian blue in Japanese paintings, alone or mixed together. Recent measurements carried out on bluish areas of an ukiyo-e designed by Utamaro showed the simultaneous use of the two pigments. However, if visible reflectance spectroscopy suggested the single use of Indigo, Fourier transform infrared spectroscopy (FTIR) also indicated the presence of Prussian blue. These results question about the possible identification of all the pigments of a colored mixture by using a single analytical technique. Without using FTIR spectroscopy, the Prussian blue would not have been detected, whereas on infrared spectra the expected specific bands ascribed to indigo are not identified. The objective of this work is to investigate mixtures of pigments, using noninvasive spectroscopic techniques in order to assess their limits of detection. Fluorimetry, hyperspectral imaging, and infrared spectroscopies have been performed on three color charts made of indigo, Prussian blue, and mixtures of them at different proportions of matter. The results emphasize the systematic identification of Prussian blue thanks to infrared spectroscopy, whereas the identification of indigo, mixed with Prussian blue, appears to be more challenging.     

Changes in protein synthesis during thermal adaptation of Propionibacterium freudenreichii subsp. shermanii

Dairy propionibacteria are present in Graviera Kritis, a traditional Gruyère-type cheese made without added propionic starter. Ten isolated strains were identified by a combination of SDS-PAGE, species-specific PCR and according to their ability to ferment lactose. They were all found to belong to the Propionibacterium freudenreichii subsp. shermanii species. Because of the stressing Gruyère technology, which includes cooking at 52 to 53 degrees C their thermotolerance was investigated at 55 degrees C. Thermotolerant and thermosensitive strains were clearly discriminated. Interestingly, the reference strain CIP 103027 belongs to the sensitive subset. One sensitive strain, ACA-DC 1305 and one tolerant, ACA-DC 1451, were selected for further study and compared to CIP 103027. For the sensitive strains ACA-DC 1305 and CIP 103027, heat pre-treatment at 42 degrees C conferred thermoprotection of cells at the lethal temperature of 55 degrees C, while there was less effect on the tolerant ACA-DC 1451. No cross-protection of salt-adapted cells against heat stress was observed for none of the strains. Differential proteomic analysis revealed distinct but overlapping cell responses to heat stress between sensitive and tolerant strains. Thermal adaptation upregulated typical HSPs involved in protein repair or turnover in the sensitive one. In the tolerant one, a distinct subset of proteins was overexpressed, whatever the temperature used, in addition to HSPs. This included enzymes involved in propionic fermentation, amino acid metabolism, oxidative stress remediation and nucleotide phosphorylation. These results bring new insights into thermoprotection in propionibacteria and the occurrence of divergent phenotypes within a same subspecies.     

X-ray multilayer monochromator with enhanced performance

An x-ray multilayer monochromator with improved resolution and a low specular background is presented. The monochromator consists of a lamellar multilayer amplitude grating with appropriate parameters used at the zeroth diffraction order. The device is fabricated by means of combining deposition of thin films on a nanometer scale, UV lithography, and reactive ion etching. The performance of this new monochromator at photon energies near 1500 eV is shown.