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This study demonstrates the simultaneous production of bioelectricity and added-value pigments in a Photosynthetic Alga Microbial Fuel Cell (PAMFC). A PAMFC was operated using Chlorella vulgaris in the cathode compartment and a bacterial consortium in the anode. The system was studied at two different light intensities and the maximum power produced was 62.7 mW/m(2) with a light intensity of 96 μE/(m(2)s). The results showed that increasing light intensity from 26 to 96 μE/(m(2)s) leads to an increase of about 6-folds in the power produced. Additionally, the pigments produced by the microalga were analysed and the results showed that the light intensity and PAMFC operation potentiated the carotenogenesis in the cathode compartment. The demonstrated possibility of producing added-value microalgae biomass in microbial fuel cell cathodes will increase the economic feasibility of these bioelectrochemical systems, allowing the development of energy efficient systems for wastewater treatment and carbon fixation.

Resume L’objectif de la Table Ronde etait d’aborder la Recherche Pre-competitive pour la premiere fois lors des Rencontres de Giens. Les participants venaient de l’industrie du medicament, des biotech, de l’industrie du dispositif, de l’academie, des services et societes de valorisation, des ministeres, du monde de la recherche clinique et fondamentale. Ils ont fait le constat des changements profonds dans la connaissance des maladies et dans le developpement des medicaments. A l’aide d’exemples dans le monde de la Sante et en dehors, ils ont identifie les principes, les enjeux, les facteurs de succes et de risque de la recherche precompetitive. Les particularites de la gestion de la propriete intellectuelle ont ete plus particulierement etudiees. La Table Ronde a conclu sur les principes de la recherche precompetitive en Sante, une revolution culturelle necessaire. C’est developper une recherche en partenariat fondee sur des principes nouveaux : i) comprendre et partager ; ii) integrer la complexite du vivant ; iii) agir dans l’interdisciplinarite.

One of the major steps limiting nonviral gene transfer efficiency is the entry of plasmid DNA from the cytoplasm into the nucleus of the transfected cells. The nuclear localization signal (NLS) of the SV40 large T antigen is known to efficiently induce nuclear targeting of proteins. We have developed two chemical strategies for covalent coupling of NLS peptides to plasmid DNA. One method involves a site-specific labeling of plasmid DNA by formation of a triple helix with an oligonucleotide–NLS peptide conjugate. After such modification with one NLS peptide per plasmid molecule, plasmid DNA remained fully active in cationic lipid-mediated transfection. In the other method, we randomly coupled 5–115 p-azidotetrafluorobenzyllissamine–NLS peptide molecules per plasmid DNA by photoactivation. Oligonucleotide–NLS and plasmid–lissamine–NLS conjugates interacted specifically with the NLS-receptor importin α. Plasmid–lissamine–NLS conjugates were not detected in the nucleus, after cytoplasmic microinjection. Plasmids did not diffuse from the site of injection and plasmid–lissamine–NLS conjugates appeared to be progressively degraded in the cytoplasm. The process of plasmid DNA sequestration/degradation stressed in this study might be as important in limiting the efficiency of nonviral gene transfer as the generally recognized entry step of plasmid DNA from the cytoplasm into the nucleus

Concentrated dispersions of nanometric lipid vesicles (mean diameter 20 nm) in water/maltose solutions have been freeze-dried and then redispersed in water, yielding again dispersions of lipid vesicles. At each stage of the freeze-drying process, the organization of the vesicles in the dispersion and their size distribution were examined through small-angle neutron scattering and gel permeation chromatography. It was found that the osmotic deswelling of the vesicles caused them to recombine into larger vesicles. A single burst of recombination events occurred when the maltose concentration in the aqueous phase rose above 100 g/L. The final vesicle population was monopopulated, with a central diameter about twice as large as that of the original dispersion.

The hydration behavior of an amphiphilic excipient, Gelucire 44/14, has been investigated. Two types of hydration processes were studied: one with increasing humidity to investigate the conditions during storage, and one with increasing water contents to study the behavior during dissolution. In addition, the main components of the excipient were investigated separately. These were polyethylene glycol (PEG), PEG monolaurate and PEG dilaurate (PEG esters), trilaurin (glyceride) and glycerol. The water uptake of Gelucire 44/14 at humidity ratios less than 60%RH was very low (about 1 wt%), which was attributed to the dissolution of the most hydrophilic component, glycerol. The water uptake increased substantially above 70%RH as PEG started to dissolve, followed by the PEG esters. It was concluded that each component equilibrates separately with the aqueous solution, which itself is in equilibrium with the humid air. Hence, a liquid phase can form between the crystals with a chemical potential decided by the humidity ratio. The water uptake of Gelucire 44/14 could be described as a sum of the uptake of the individual components, weighted according to their relative amounts in the mixture. Phase maps of the Gelucire 44/14 and its components at different water contents were constructed. Dry Gelucire 44/14 contains lamellar crystals of mainly PEG and PEG esters which melt at 44 ºC. The crystals do not swell at increasing humidity, but dissolve above 75%RH at a water content of 5 wt% in the excipient. At increasing water contents Gelucire 44/14 forms white gels composed of hexagonal and lamellar mesophases dispersed in a continuous liquid phase. These liquid crystalline phases dissolve at 35 ºC, i.e. below physiological temperatures. A dramatic viscosity maximum was observed in the lamellar region at 50 wt% water, which may be attributed to the formation of networks of PEG esters. The pure PEG esters were found to form cubic mesophases at 50 wt% water. The instruments used in this study were Dynamic Vapor Sorption (DVS), Thermal Gravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC), Small- and Wide Angle X-ray Scattering (SWAXS) and Optical Microscopy.

We have developed a chemical strategy for covalent coupling of fluorophores to plasmid DNA. A p-azido-tetrafluoro-benzyl-lissamine conjugate was synthesized and purified. This conjugate was used to covalently associate fluorescent molecules to plasmid DNA by photoactivation. In contrast to nick-translated plasmid DNA, plasmid-lissamine conjugates appeared on gel as supercoiled DNA. Reporter gene was expressed after transfection of the plasmid-lissamine conjugates in NIH 3T3 cells, although gene transfer efficiency was decreased by 60% as compared with unlabeled DNA. Intracellular traffic of plasmid-lissamine conjugates was studied in transfected cells. After cytoplasmic microinjection, fluorescent plasmid did not diffuse from the site of injection and appeared to be progressively degraded in the cytoplasm.

The nuclear localization signal (NLS) of the SV40 large T antigen efficiently induces nuclear entry of proteins. We have developed a strategy for covalent coupling of one or a controlled number of NLS peptides to plasmid DNA at a specific site by triple helix formation. A psoralen-oligonucleotide-NLS peptide conjugate was synthesized and characterized by proteolysis with trypsin. This conjugate was used to covalently associate one NLS peptide to plasmid DNA by triple helix formation and photoactivation. The oligonucleotide-NLS peptide conjugate interacted with the NLS-receptor importin α. The reporter gene was expressed after transfection of the modified plasmid in NIH 3T3 cells, indicating no loss of the gene expression functionality of the plasmid. On the other hand, no increase in expression was observed as a result of the NLS peptide. This site-specific coupling technology can be used to couple to a plasmid other ligands targeting to a specific receptor.