Physiological approach to heterologous human serum albumin production by Kluyveromyces lactis in chemostat culture

Production of recombinant human serum albumin (rHSA) controlled by the constitutive promoter phosphoglycerate kinase was studied in Kluyveromyces lactis. It was governed by both cell concentration and glycolytic flow. The triggering of the fermentation metabolism by unfavourable culture conditions (pH, pO₂, D) caused a decrease in the synthesis of the heterologous protein. The highest productivity (75 mg 1^?1 per h) and rHSA concentration (62 mg 1^?1) were obtained in chemostat culture with a dilution rate of 0·12 h^?1 and with 38 g 1^?1 dry weight.     

Rapid immunoblot and kinase assay tests for a syndromal form of X linked mental retardation: Coffin-Lowry syndrome

Coffin-Lowry syndrome (CLS) is a syndromal form of X linked mental retardation, in which some associated facial, hand, and skeletal abnormalities are diagnostic features. Accurate diagnosis, critical for genetic counselling, is often difficult, especially in early childhood. We have recently shown that Coffin-Lowry syndrome is caused by mutations in the gene encoding RSK2, a growth factor regulated protein kinase. RSK2 mutations are very heterogeneous and most of them lead to premature termination of translation or to loss of phosphotransferase activity or both. In the present study, we have evaluated immunoblot and RSK2 kinase assays as a rapid and simple diagnostic test for CLS, using cultured lymphoblastoid or fibroblast cell lines. Western blot analysis failed to detect RSK2 in six patients, suggesting the presence of truncated proteins in these patients. This conclusion was confirmed in four patients, in whom the causative mutations, all leading to premature termination of translation, were identified. Of four patients showing a normal amount of RSK2 protein on western blot and tested for RSK2 phosphotransferase activity, one had a dramatically impaired activity. Analysis of the RSK2 cDNA sequence in this patient showed a mutation of a putative phosphorylation site that would be critical for RSK2 activity. Preliminary results show that, at least, the western blot protocol can be successfully applied to lymphocyte protein extracts prepared directly from blood samples. These assays promise to become important diagnostic tools for CLS, particularly with regard to very young patients with no family history of the condition.     

Teaching sustainable design in architecture education: Critical review of Easy Approach for Sustainable and Environmental Design (EASED)

In the current context of climate change and ecological awareness, designing sustainable environments is definitely understood as a shared responsibility. With the construction sector consuming half of the world׳s energy, the role of some key stakeholders such as architects becomes even more critical when providing responsible and relevant design for the built environment. Thus, improving the way our environments are being designed challenges some cultural systems that show evident limits, such as the training of future architects and engineers.In this research, the focus is on architecture students and aims to demonstrate how the use of a new sustainable performance simulation tool, called Easy Approach for Sustainable and Environmental Design (EASED) could contribute to educate them about innovatively sustainable design. This was assessed through the evaluation of student engagement, their use of the tool and its appropriation. Results show that individual work was not convincing, whereas success was met during group work. Limits and improvement possibilities were found in the interface of EASED as well as in the educational set up of the tool.     

Parameters effect on proton conductivity to obtain chitosan membranes for use as electrolytes in PEMFC

The chitosan biopolymer can be used as a proton‐conducting membrane in proton‐exchange membrane fuel cell. In the forms that they have normally obtained and tested, chitosan membranes typically show poor performance in conduction of protons, requiring modifications in the structure of the biopolymer or blending with other polymers to increase its proton conductivity. The present work investigates the individual properties of chitosan and relates them to the proton conductivity performance of membranes composed of this polymer. Evaluation was made of the effects of variables such as the degree of deacetylation (DD) and the molar mass (Mv) of chitosan membranes without addition of any other polymer. The DD and Mv values of the chitosan used to produce membranes determined the proton conduction, with lower DD and higher Mv resulting in higher conductivity. The thicker membranes presented greater crystallinity, with conductivity between 2.0 × 10^?4 and 1.8 × 10^?3 S cm^?1. The characteristic stages of degradation of the chitosan membranes were in the ranges 200 to 300°C and 500 to 600°C, indicating good thermal stability of the material.     

Involvement of Microglia in Neurodegenerative Diseases: Beneficial Effects of Docosahexahenoic Acid (DHA) Supplied by Food or Combined with Nanoparticles

Neurodegenerative diseases represent a major public health issue and require better therapeutic management. The treatments developed mainly target neuronal activity. However, an inflammatory component must be considered, and microglia may constitute an important therapeutic target. Given the difficulty in developing molecules that can cross the blood–brain barrier, the use of food-derived molecules may be an interesting therapeutic avenue. Docosahexaenoic acid (DHA), an omega-3 polyunsaturated fatty acid (22:6 omega-3), has an inhibitory action on cell death and oxidative stress induced in the microglia. It also acts on the inflammatory activity of microglia. These data obtained in vitro or on animal models are corroborated by clinical trials showing a protective effect of DHA. Whereas DHA crosses the blood–brain barrier, nutritional intake lacks specificity at both the tissue and cellular level. Nanomedicine offers new tools which favor the delivery of DHA at the cerebral level, especially in microglial cells. Because of the biological activities of DHA and the associated nanotargeting techniques, DHA represents a therapeutic molecule of interest for the treatment of neurodegenerative diseases.     

Quantification of clay dispersion in nanocomposites of styrenic polymers

Polymer‐clay nanocomposites are materials with many interesting structures, properties, and potential applications. Microstructural evaluation of a nanocomposite is not an easy task, as clay may form hierarchical structures which may look different when observed at various magnifications under a microscope, and also as the concepts of “intercalation” and “exfoliation” are not self‐sufficient to describe its morphology. In this work polymer‐clay nanocomposites of polystyrene and two styrene‐containing block copolymers (styrene‐butadiene‐styrene and styrene‐ethylene/butylene‐styrene) were prepared using three different techniques. Clay dispersion was evaluated by a recently developed microscopy image analysis procedure, combining the analysis of optical and transmission electron micrographs, and the characterization was complemented by X‐ray diffraction and rheological measurements. The results showed better clay dispersion for both block copolymers nanocomposites, mainly due to their molecular architectures. Moreover, the techniques which showed the best results involved mixing the materials in a solvent medium. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers     

Electrochemical mineralization of sodium dodecylbenzenesulfonate at boron doped diamond anodes

Results are reported of the electrochemical oxidation of sodium dodecylbenzenesulfonate (SDBS), a common surfactant, at boron-doped diamond anodes. The measured critical micelle concentration (CMC) for SDBS in water at 24 °C was almost 150 mg dm⁻³, but this decreased to almost 30 mg dm⁻³ in 0.1 M sodium sulfate. Cyclic voltammetry of a boron doped diamond (BDD) electrode in aqueous SDBS solutions exhibited oxidation current densities at very positive potentials; however, solutions of monomers at concentrations <CMC gave rise to higher current densities than in higher concentration solutions that formed micelles. Galvanostatic electrolyses, with samples analyzed for Total Organic Carbon (TOC) and Chemical Oxygen Demand (COD), were performed in an electrolytic flow cell without separator, operating in batch recycle mode, using solutions containing SDBS at initial concentrations of 25 and 250 ppm. SDBS in basic media (pH = 12) exhibited lower TOC removal rates than in acidic or neutral solutions, due to concurrent oxidation of dissolved carbonates at potentials less positive than required for water oxidation, as evident in cyclic voltammograms. Decreasing the [electrolyte]/[surfactant] ratio from 200 to 10 increased TOC removal rates. For solutions containing monomers, TOC removal rates also increased with flow rate in the second part of the electrolysis, corresponding to reaction of smaller, fragmented organic compounds. When COD removal from a solution containing SDBS micelles was mass transport controlled, current efficiencies were constant at ca. 50%, due to dimerisation of hydroxyl radical to H₂O₂ and its oxidation to dioxygen.