Chlamydomonas reinhardtii genetic variants as probes for fluorescence sensing system in detection of pollutants

The unicellular green alga Chlamydomonas reinhardtii is employed here for the setup of a biosensor demonstrator based on multibiomediators for the detection of herbicides. The detection is based on the activity of photosystem II, the multienzymatic chlorophyll–protein complex located in the thylakoid membrane that catalyzes the light-dependent photosynthetic primary charge separation and the electron transfer chain in cyanobacteria, algae, and higher plants. Several C. reinhardtii mutants modified on the D1 photosystem II protein are generated by site-directed mutagenesis and experimentally tested for the development of a biosensor revealing the modification of the fluorescence parameter (1 − V _J) in the presence of herbicides. The A250R, A250L, A251C, and I163N mutants are highly sensitive to the urea and triazine herbicide classes; the newly generated F255N mutant is shown to be especially resistant to the class of urea. It follows that the response of the multibiomediators is associated to a particular herbicide subclass and can be useful to monitor several species of pollutants.     

Electron paramagnetic resonance of radicals induced in drugs and excipients by radiation or mechanical treatments

Radiation as well as mechanical treatments induced in drugs and excipients radicals, which can be studied by electron paramagnetic resonance. A special attention is pointed about the use of electron paramagnetic resonance (EPR) to bring the proof whether or not a drug has been irradiated or not. We also discuss of other methods (thermoluminescence (TL), gas phase chromatography (GPC)) which can be used to bring the same proof in case of irradiated drugs, excipients and cosmetic products.     

Microbubble mediated sonoporation of cells in suspension: Clonogenic viability and influence of molecular size on uptake

This work investigates whether the application of sonoporation is limited by the size of a macromolecule being delivered and by the ability of cells to proliferate following uptake. KHT-C cells in suspension were exposed to variations in ultrasound pressure (0-570 kPa) and microbubble shell-type (lipid and protein) at fixed settings of 500 kHz centre frequency, 32 μs pulse duration, 3 kHz pulse repetition frequency and 2 min insonation. Reversible permeability (P_R), defined as the number of cells stained with FITC-dextran and unstained with propidium iodide (i.e., PI-viable), was measured with flow cytometry for marker molecules ranging from 10 kDa to 2 MDa in size. Viable permeability (P_V) defined as the number of permeabilised cells that maintained their ability to proliferate, was measured by clonogenic assay. Comparable intracellular delivery of all sizes of molecules was achieved, indicating that intracellular delivery of common therapeutic drugs may not be limited by molecular size. Maximum P_R’s of 80% (at 10 kDa) and 55% (at 10 kDa) were achieved with lipid coated bubbles at 3.3% v/v and protein coated bubbles at 6.7% v/v concentrations. The PI-viability was approximately 80% at 570 kPa in both cases. The maximum P_V achieved with both agents was 22%, while inducing a lower overall clonogenic viability with the lipid (39%) compared to the protein (56%) shelled bubbles. This study demonstrates that large macromolecules, up to 2 MDa in size, can be delivered with high efficiency to cells which undergo reversible permeabilisation, maintaining long-term viability in approximately half of the cells.     

A point about electron paramagnetic resonance detection of irradiated foodstuffs

This paper makes a point about the identification of irradiated foodstuffs by means of electron paramagnetic resonance (EPR) or electron spin resonance (ESR). EPR is the most accurate method for such routine applications since radicals are stabilised for a long time in all (or part of) foods that are in solid and dry states; consequently, EPR can be applied to meat and fish bones, fruit and relative products (from vegetal origin). More details are given for mollusc shells, such as oysters and mussels.     

Electron paramagnetic resonance detection of irradiated foodstuffs

This item deals with identification of irradiated foodstuffs by means of Electron Paramagnetic Resonance (EPR). EPR is the most accurate method for such routine applications since radicals are stabilized for a long time in all (part of) foods which are in solid and dry state; consequently, EPR can be applied to meat and fish bones, fruit and relative products (from vegetal origin), seafoods, etc.     

Spectroscopic study of bituminous oxidative stress

Bitumen, as each organic substance, is a product which alters over time. Indeed, roads deteriorate under the effect of several phenomena. A number of studies have been undertaken to increase the quality of road's coating, mostly by adding polymer to bitumen. This work was based on the study, by electron paramagnetic resonance (EPR), FTIR and Synchronous UV fluorescence, of different base and modified bitumens after different treatments used to simulate the ageing (gamma irradiation, thermal treatment). Our purpose was to compare and correlate the results obtained by different techniques to improve the knowledge of bitumen's reactivity and evolution submitted to ageing phenomena.     

Identification of irradiation treatment of aromatic herbs, spices and fruits by electron paramagnetic resonance and thermoluminescence

Electron paramagnetic resonance and thermoluminescence signals induced by gamma irradiation in some herbs, spices and fruits were systematically studied in order to detect the treatment. Using European protocols the validity and effectiveness of these two techniques are compared in regard to time of storage after irradiation.     

High-speed capillary gas chromatography for determination of inhalation anesthetics

To increase sample throughput for GC analysis of inhalation anaesthetics without affecting the separation of nitrous oxide (N2O) and halogenated anaesthetics (sevoflurane, isoflurane and halothane), we explored the effectiveness of a tailor-shortened (12 m) PlotQ capillary column and developed a high-speed version of a previously reported GC technique (involving chromatographic separation of analytes using a GC-MS system, coupled with a selected ion monitoring (SIM) method to increase sensitivity). Efficient separation and repeatable results were achieved at a reduced runtime of approximately 7 min (versus 18 min with the original method) at a carrier gas flow of 1.5 ml/min. This approach should more than double the previous throughput.