Difference of Body Compositional Changes According to the Presence of Weight Cycling in a Community-based Weight Control Program

Many obese people who try to control body weight experience weight cycling (WC). The present study evaluated the importance of WC in a community-based obesity intervention program. We analyzed the data of 109 Korean participants (86% women) among 177 subjects who had completed a 12-week intervention program at two public health centers in Korea from April to December, 2007. Completion of a self-administrated questionnaire at baseline was used to obtain anthropometric measurements, and laboratory testing was done before and after the program. Differences in body composition change and obesity-related life style between the two groups were compared with respect to WC and non-weight cycling (NWC). After 12 weeks, both groups showed reductions in weight, waist circumference, and body mass index. The group differences were not significant. However, significant differences were evident for the WC group compared to the NWC group in fat percent mass (WC vs. NWC, -3.49±2.31% vs. -4.65±2.59%, P=0.01), fat free mass (WC vs. NWC, -0.95±1.37 kg vs. -0.38±1.05 kg, P=0.01), and total cholesterol (WC vs. NWC, -3.32±14.63 vs. -16.54±32.39, P=0.005). In conducting a community-based weight control program that predominantly targets women, changes of body composition and total cholesterol may be less effective in weight cyclers than in non-weight cyclers

Le criblage à Roscoff

Les scientifiques de la station biologique de Roscoff (SBR) travaillent depuis plusieurs dizaines d’années sur la régulation de la division cellulaire en utilisant, comme modèles, des organismes marins. Ceci a notamment conduit à l’étude de kinases dépendantes des cyclines (CDK) qui contrôlent le déroulement du cycle cellulaire. Ces cibles ont ensuite été utilisées afin de caractériser des inhibiteurs pharmacologiques, ou « touches » (hits), en mettant en place un criblage automatisé. Le mécanisme d’action des meilleures touches sélectionnées a également été étudié en les dérivant, afin de procéder à des approches de criblages inverses par chromatographie d’affinité. À l’interface entre biologie et chimie, le travail de cette plate-forme place au centre des recherches le composé chimique, qui est à la fois (1) une molécule d’intérêt thérapeutique et (2) un outil moléculaire permettant d’analyser la fonction cellulaire des kinases ciblées. À partir d’organismes marins, huit familles structurales d’inhibiteurs ont été caractérisées sur la plate-forme, et l’espoir est grand de voir la mer nous en apporter de nouveaux, encore plus puissants

Selection and optimisation of a method for efficient metabolites extraction from microalgae

Over the last decade, the use of microalgae for biofuel production and carbon dioxide sequestration has become a challenge worldwide. Processing costs are still too high for these methods to be profitable though, leading to a need to find high value by-products to optimise the added value of this biomass. For high-throughput screening of such metabolites, it is essential to reach the inner content of the cell. This paper presents research and development of a technique enabling a high extraction yield of any metabolite, taking into account the difficulty of extracting bound and or inaccessible molecules with a wide variety of polarities. To this end, several disruption techniques were tested at laboratory scale on two biological models: Porphyridium purpureum and Phaeodactylum tricornutum. A mixer mill gave the best results, offering access to a broad diversity of metabolites from microalgae for high-throughput screening

Community analysis of pigment patterns from 37 microalgae strains reveals new carotenoids and porphyrins characteristic of distinct strains and taxonomic groups

Phytoplankton, with an estimated 30 000 to 1 000 000 species clustered in 12 phyla, presents a high taxonomic and ecophysiological diversity, reflected by the complex distribution of pigments among the different algal classes. High performance liquid chromatography is the gold standard method for qualitative and quantitative analysis of phytoplankton pigments in seawater and culture samples, but only a few pigments can be used as robust chemotaxonomic markers. A major challenge is thus to identify new ones, characteristic of a strain, species, class or taxon that cannot be currently identified on the basis of its pigment signature. Using an optimized extraction process coupled to a HPLC de-replication strategy, we examined the pigment composition of 37 microalgae strains, representative of the broad taxonomic diversity of marine and freshwater species (excluding cyanobacteria). For each species, the major pigments already described were unambiguously identified. We also observed the presence of several minor unidentified pigments in each chromatogram. The global analysis of pigment compositions revealed a total of 124 pigments, including 98 pigments or derivatives unidentified using the standards. Absorption spectra indicated that 35 corresponded to chlorophyll/porphyrin derivatives, 57 to carotenoids and six to derivatives having both spectral signatures. Sixty-one of these unidentified or new carotenoids and porphyrin derivatives were characteristic of particular strains or species, indicating their possible use as highly specific chemotaxonomic markers capable of identifying one strain out of the 37 selected. We developed a graphical analysis using Gephi software to give a clear representation of pigment communities among the various phytoplankton strains, and to reveal strain-characteristic and shared pigments. This made it possible to reconstruct the taxonomic evolution of microalgae classes, on the basis of the conservation, loss, and/or appearance of pigments

Pigment communities among strains containing a Diato/Diadino cycle (Haptophyta, Ochrophyta, Dinophyta and Euglenozophyta).

<p>Pigment communities among strains containing a Diato/Diadino cycle (Haptophyta, Ochrophyta, Dinophyta and Euglenozophyta).</p

Key pigments to identify the 37 phytoplankton strains.

<p>Key pigments to identify the 37 phytoplankton strains.</p

Pigment communities among green strains, using the zeaxanthin/antheraxanthin/violaxanthin cycle for photoprotection (Charophyta, Chlorophyta and Cercozoa).

<p>Pigment communities among green strains, using the zeaxanthin/antheraxanthin/violaxanthin cycle for photoprotection (Charophyta, Chlorophyta and Cercozoa).</p

Study on the microalgal pigments extraction process: Performance of microwave assisted extraction

The performance of microwaves irradiation (MAE and VMAE) to extract pigments from two marine microalgae was compared to conventional processes (cold and hot soaking and ultrasound-assisted extraction). Pigments were quantified by RP-HPLC and extraction performance was assessed regarding rapidity, reproducibility and extraction yields. Scanning electron microscopy was used at all extraction steps to assess the impact of the process on microalgal cell integrity. Freeze-drying and pigments extraction preserved microalgae cell integrity (except sonication) and evoked agglutination in superposed cells layers. All processes performed on Dunaliella tertiolecta (chlorophyte) lead to rapid pigments extraction, and equivalent pigments extraction yields, the absence of frustule allowing immediate solvent penetration in microalgae cells. In contrast, presence of the frustule in the diatom Cylindrotheca closterium (bacillariophyte) constituted a mechanical barrier to pigment extraction. MAE was identified as the best extraction process for CC pigments as it combined rapidity, reproducibility, homogeneous heating and high extraction yields. (C) 2010 Elsevier Ltd. All rights reserved