Photografted methacrylate-based monolithic columns coated with cellulose tris(3,5-dimethylphenylcarbamate) for chiral separation in CEC

A chiral capillary monolithic column for enantiomer separation in capillary electrochromatography was prepared by coating cellulose tris(3,5-dimethylphenylcarbamate) on porous glycidyl methacrylate-co-ethylene dimethacrylate monolith in capillary format grafted with chains of [2(methacryloyloxy)ethyl] trimethylammonium chloride. The surface modification of the monolith by the photografting of [2(methacryloyloxy)ethyl] trimethylammonium chloride monomer as well as the coating conditions of cellulose tris(3,5-dimethylphenylcarbamate) onto the grafted monolithic scaffold were optimized to obtain a stable and reproducible chiral stationary phase for capillary electrochromatography. The effect of organic modifier (acetonitrile) in aqueous mobile phase for the enantiomer separation by capillary electrochromatography was also investigated. Several pairs of enantiomers including acidic, neutral, and basic analytes were tested and most of them were partially or completely resolved under aqueous mobile phases. The prepared monolithic chiral stationary phases exhibited a good stability, repeatability, and column-to-column reproducibility, with relative standard deviations below 11% in the studied electrochromatographic parameters.Fil: Echevarria, Romina Noel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Exactas; ArgentinaFil: Carrasco Correa, Enrique Javier. Universidad de Valencia; EspañaFil: Keunchkarian, Sonia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Exactas; ArgentinaFil: Reta, Mario Roberto. Universidad Nacional de La Plata. Facultad de Ciencias Exactas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Herrero Martinez, José Manuel. Universidad de Valencia; Españ

Characterization of the role that bacterial surface polysaccharide poly N-acetyl glucosamine plays in nonvaccine serotypes of streptococcus pneumoniae colonization and pathogenicity

Poly N-acetyl glucosamine is a cell surface polysaccharide that has been characterized in Staphylococcus epidermidis and Staphylococcus aureus as involved in biofilm formation and implicated in virulence. Its role in bacterial colonization and pathogenicity is now being characterized in Streptococcus pneumoniae. The aim of this thesis was to produce PNAG-deficient S. pneumoniae mutants and to confirm differential levels of biofilm formation in PNAG-deficient mutants in comparison to their wild type strains. Using PCR, gel electrophoresis, and indirect immunofluorescence, successful transformations of PNAG-deficient mutants were confirmed. Biofilm assays provided preliminary data for further investigation of the role that PNAG plays in colonization in S. pneumoniae. A novel finding in PNAG genetic structure in S. pneumoniae was also discovered, providing a new avenue of research on PNAG

The Update, March 22, 2010

The Update is a bi-weekly web newsletter published by the Iowa Department of Public Health's Bureau of Family Health. It is posted the second and fourth week of every month, and provides useful job resource information for departmental health care professionals, information on training opportunities, intradepartmental reports and meetings, and additional information pertinent to health care professionals

The way to ultrafast, high-throughput enantioseparations of bioactive compounds in liquid and supercritical fluid chromatography

Until less than 10 years ago, chiral separations were carried out with columns packed with 5 or 3 μm fully porous particles (FPPs). Times to resolve enantiomeric mixtures were easily larger than 30 min, or so. Pushed especially by stringent requirements from medicinal and pharmaceutical industries, during the last years the field of chiral separations by liquid chromatography has undergone what can be defined a “true revolution”. With the purpose of developing ever faster and efficient method of separations, indeed, very efficient particle formats, such as superficially porous particles (SPPs) or sub-2 μm FPPs, have been functionalized with chiral selectors and employed in ultrafast applications. Thanks to the use of short column (1–2 cm long), packed with these extremely efficient chiral stationary phases (CSPs), operated at very high flow rates (5–8 mL/min), resolution of racemates could be accomplished in very short time, in many cases less than 1 s in normal-, reversed-phase and HILIC conditions. These CSPs have been found to be particularly promising also to carry out high-throughput separations under supercritical fluid chromatography (SFC) conditions. The most important results that have been recently achieved in terms of ultrafast, high-throughput enantioseparations both in liquid and supercritical fluid chromatography with particular attention to the very important field of bioactive chiral compounds will be reviewed in this manuscript. Attention will be focused not only on the latest introduced CSPs and their applications, but also on instrumental modifications which are required in some cases in order to fully exploit the intrinsic potential of new generation chiral columns

Pneumococcal biofilms

Over 60% of bacterial infections (and up to 80% of chronic infections) are currently considered to involve microbial growth in biofilms. This peculiar form of life poses an array of problems in human clinical practice, from infections associated with the implant of prosthetic devices and dental plaque formation to diseases such as cystic fibrosis, otitis media, and endocarditis. Biofilms are also at the basis of a variety of problems in industry. This report describes the biofilms produced by Streptococcus pneumoniae. This bacterium often colonizes the upper airways in humans as a normal commensal, yet it may spread to other areas of the body, causing otitis media, pneumonia, or invasive diseases such as bacteremia and meningitis. The capacity of S. pneumoniae to form biofilms had not been explored until recently. Several newly developed in vitro systems have allowed to test the capacity of S. pneumoniae to form biofilms, and to analyze the influence of several factors, including DNA and proteins—which play a role in the virulence of this “supergerm” in the formation and development of biofilms. In this brief review, we update the knowledge available on pneumococcal biofilm formation and the unusual features of this structure

Heterologous expression and functional characterization of a GH10 endoxylanase from \u3ci\u3eAspergillus fumigatus\u3c/i\u3e var. \u3ci\u3eniveus\u3c/i\u3e with potential biotechnological application

Xylanases decrease the xylan content in pretreated biomass releasing it from hemicellulose, thus improving the accessibility of cellulose for cellulases. In this work, an endo-β-1,4-xylanase from Aspergillus fumigatus var. niveus (AFUMN-GH10) was successfully expressed. The structural analysis and biochemical characterization showed this AFUMN-GH10 does not contain a carbohydrate-binding module. The enzyme retained its activity in a pH range from 4.5 to 7.0, with an optimal temperature at 60°C. AFUMN-GH10 showed the highest activity in beechwood xylan. The mode of action of AFUMNGH10 was investigated by hydrolysis of APTS-labeled xylohexaose, which resulted in xylotriose and xylobiose as the main products. AFUMN-GH10 released 27% of residual xylan from hydrothermally-pretreated corn stover and 14% of residual xylan from hydrothermally-pretreated sugarcane bagasse. The results showed that environmentally friendly pretreatment followed by enzymatic hydrolysis with AFUMN-GH10 in low concentration is a suitable method to remove part of residual and recalcitrant hemicellulose from biomass

Cordyceps Sinensis: anti-fibrotic and inflammatory effects of a cultured polysaccharide extract

It has been suggested that the traditional Chinese herbal preparation Cordyceps Sinensis (CS) may have a beneficial effect in renal disease. To satisfy increasing demand, CS derivatives have been produced by aseptic mycelia cultivation. We have demonstrated antifibrotic activity of cultured CS previously. The aim of this study was to examine bioactivity of a polysaccharide isolated from cultured CS with a complicated monosaccharide composition, mainly consisting of Gal, Glc and Man. This polysaccharide antagonised the effect of TGF-b1 in stimulating the expression of collagen in the HK2 renal cell line. This was associated with down regulation of the TGF-b receptor Alk5. In addition the polysaccharide antagonised IL-1b stimulated sICAM-1 dependent adherence of monocytes to a monolayer of HK2 cell. This was associated with increased expression of the primary receptor for hyaluronan CD44, and was abrogated by removal of the cell surface hyaluronan pericellular coat. In summary we describe both anti-fibrotic and anti-inflammatory activity in a polysaccharide isolated from cultured CS