Expression and functional characterisation of genes putatively involved in freezing tolerance in Arctic species of Vaccinium.

Freezing temperatures are responsible for destroying vast areas of crops globally each year and are a major factor in explaining the size and distribution of plants. The ability of plants to survive freezing events, depends on predictable and gradual lowering of temperatures, allowing cold acclimation to occur before freezing temperatures arrive. Climate change is altering maximum and minimum temperatures globally and, making freezing events less predictable. A further understanding of the molecular mechanisms of acquired freezing tolerance would give insights into potential genetic targets for crop improvement. In Arabidopsis, CBF/DREB1 transcription factors are currently the most well characterised proteins associated with acquired freezing-tolerance. Studies were performed on three species of Vaccinium collected from the Arctic, V. myrtillus, V. uliginosum and V. vitis-idaea. Genes encoding CBF/DREB1 transcription factors from each of these Arctic species were isolated, sequenced and expressed in Arabidopsis. Characterisation studies were performed on transgenic lines generated from each of the three Vaccinium species. Induced COR gene expression, freezing tolerance and altered phenotype were measured in these lines. Results showed that V. myrtillus CBF/DREB1 can induce freezing tolerance in Arabidopsis. Western blot and reporter gene assay analysis of transiently-expressed CBF/DREB1 from Vaccinium, highlighted the possibility that the CBF/DREB1 from V. uliginosum was less stable than the CBF/DREB1 from the other two species. Site-directed mutagenesis of five regions of interest between the three Vaccinium species showed that the substitution of two amino acids improved COR gene binding/induction. This substitution could serve as a potential crop improvement site for commercial blueberry crops (V. corymbosum). Other genes associated with the CBF/DREB1 pathway in Arabidopsis were cloned and sequenced from the three Vaccinium species. Cold-induced expression of these genes was tested and showed similarities in sequence and expression pattern between V. vitis-idaea and Arabidopsis

Evaluation of the hypocholesterolemic effect and prebiotic activity of a lentil (Lens culinaris Medik) extract

The aim of our work was to produce a hydroalcoholic extract of lentils and to examine: a) the hypocholesterolemic action in an animal model, by studying the plasma cholesterol level and the concentration of bile acids in the faeces; b) the potential prebiotic effect, by conducting an in vitro culture fermentation experiment and assessing the level of short chain fatty acids (SCFAs) in the faeces of rats

Encapsulation of lactobacillus casei into calcium pectinate-chitosan beads for enteric delivery

Gel beads were prepared by extrusion of various types of pectin into 0.15 M calcium chloride. Size, morphology, and textural properties of 3 types of beads were evaluated and it was established that the use of 3 w/v % amidated pectin provides the optimal characteristics suitable for encapsulation of live bacteria. Lactobacillus casei NCIMB 30185 (PXN37) was encapsulated into calcium pectinate gel through the extrusion of a live bacteria dispersion in 3 w/v % pectin into a solution of calcium chloride. The capsules were then additionally coated with chitosan. The viability of bacteria within these capsules was studied under model gastrointestinal conditions in vitro (simulated gastric and intestinal juices). It was established that pectin-chitosan capsules can provide protection to L. casei from the gastric acid and result in high levels of viable bacteria released in the intestine

Simulation study of micelle formation by bile salts

We report coarse-grained, implicit-solvent simulations of aqueous solutions of bile salts. The parameters in our model were optimized to reproduce some of the experimentally known behavior of dihydroxy bile salts at “physiological” temperature and counterion concentration. We find that micelle formation in dihydroxy and trihydroxy bile salts is only weakly cooperative in the sense that there is barely a free energy barrier that stabilizes these micelles against disassembly. Bile molecules are found to pack in many different orientations in pure bile micelles. Both features may be physiologically relevant: the ability to pack in different orientations may be necessary to form mixed micelles with nutrients of a wide range of molecular lengths and shapes, and the reduced micelle stability may facilitate nutrient release once the mixed micelles reach the intestinal wall.FOM Institute-Scientific Research (NWO). Senter-Novem -Dutch Ministry of Economic; Affairs through the Food & Nutrition Delta 2 Program -grant DFN0642300; Royal Society of London (Wolfson Merit Award) and from the ERC (Advanced Grant agreement 227758)

Agro-materials : a bibliographic review

Facing the problems of plastic recycling and fossil resources exhaustion, the use of biomass to conceive new materials appears like a reasonable solution. Two axes of research are nowadays developed : on the one hand the synthesis of biodegradable plastics, whichever the methods may be, on the other hand the utilization of raw biopolymers, which is the object of this paper. From this perspective, the “plastic” properties of natural polymers, the caracteristics of the different classes of polymers, the use of charge in vegetable matrix and the possible means of improving the durability of these agro-materials are reviewed

Wavelet spectral testing : application to nonstationary circadian rhythms

Rhythmic data are ubiquitous in the life sciences. Biologists need reliable statistical tests to identify whether a particular experimental treatment has caused a significant change in a rhythmic signal. When these signals display nonstationary behaviour, as is common in many biological systems, the established methodologies may be misleading. Therefore, there is a real need for new methodology that enables the formal comparison of nonstationary processes. As circadian behaviour is best understood in the spectral domain, here we develop novel hypothesis testing procedures in the (wavelet) spectral domain, embedding replicate information when available. The data are modelled as realisations of locally stationary wavelet processes, allowing us to define and rigorously estimate their evolutionary wavelet spectra. Motivated by three complementary applications in circadian biology, our new methodology allows the identification of three specific types of spectral difference. We demonstrate the advantages of our methodology over alternative approaches, by means of a comprehensive simulation study and real data applications, using both published and newly generated circadian datasets. In contrast to the current standard methodologies, our method successfully identifies differences within the motivating circadian datasets, and facilitates wider ranging analyses of rhythmic biological data in general