25 research outputs found
Characterisation of Films Based on Exopolysaccharides from Alteromonas Strains Isolated from French Polynesia Marine Environments
LA/P/0140/202019
UID/AGR/04129/2020
LA/P/0037/2020This work assessed the film-forming capacity of exopolysaccharides (EPS) produced by six Alteromonas strains recently isolated from different marine environments in French Polynesia atolls. The films were transparent and resulted in small colour alterations when applied over a coloured surface (ÎEab below 12.6 in the five different colours tested). Moreover, scanning electron microscopy showed that the EPS films were dense and compact, with a smooth surface. High water vapour permeabilities were observed (2.7â6.1 Ă 10â11 mol mâ1 sâ1 Paâ1), which are characteristic of hydrophilic polysaccharide films. The films were also characterised in terms of barrier properties to oxygen and carbon dioxide. Interestingly, different behaviours in terms of their mechanical properties under tensile tests were observed: three of the EPS films were ductile with high elongation at break (Δ) (35.6â47.0%), low tensile strength at break (ê) (4.55â11.7 MPa) and low Youngâs modulus (Δm) (10â93 MPa), whereas the other three were stiffer and more resistant with a higher ê (16.6â23.6 MPa), lower Δ (2.80â5.58%), and higher Δm (597â1100 MPa). These properties demonstrate the potential of Alteromonas sp. EPS films to be applied in different areas such as biomedicine, pharmaceuticals, or food packaging.publishersversionpublishe
Le Forest Rights Act, vers une lĂ©galisation des pratiques locales dans les forĂȘts indiennes ?
International audienceno abstrac
Marques, indications géographiques et certifications : comment valoriser la biodiversité dans les Ghùts occidentaux (Inde) ?
International audienceThe district of Kodagu (Coorg) in India produces between 1 and 2 % of the worldâs coffee, in multi-strata agro-forestry systems embedded between paddy fields and evergreen rainforest fragments. This complex landscape is rapidly changing. The forests have been converted into coffee plantations, the native species that form the rich canopy cover of the plantations are being replaced with exotic and fast growing species and the conflicts between humans and wildlife are increasing. In this context, we explore the potential for linking livelihood development and biodiversity conservation offered by three value-addition approaches centered on the localized productions of the district. The first one relies on trademarks comprising the name âCoorg â for marketing coffee. The second is based on the existing indian Geographical Indications legal framework, which has yet to be used for coffee from Coorg. The third one rests on the development of environmental certifications for the coffees from India. We assess the social and ecological efficiency of these three strategies and propose an analysis of the questions raised by the different degrees of implication of the stakeholders and beneficiaries of such approaches.Le district du Kodagu (Coorg) en Inde produit entre 1 et 2 % du cafĂ© mondial, dans des systĂšmes agroforestiers complexes imbriquĂ©s entre des riziĂšres et des fragments de forĂȘts sempervirentes humides. Cette mosaĂŻque paysagĂšre Ă©volue rapidement. La forĂȘt a reculĂ© au profit des plantations, le couvert arborĂ© riche en espĂšces natives est progressivement remplacĂ© par une espĂšce exotique et les conflits avec la faune se font plus frĂ©quents. Dans ce contexte, trois stratĂ©gies de valorisation commerciale sont explorĂ©es, avec une attention particuliĂšre Ă leur potentiel pour associer dĂ©veloppement Ă©conomique et conservation de la biodiversitĂ©. La premiĂšre approche repose sur lâutilisation de marques commerciales comprenant le nom « Coorg » pour du cafĂ©. La seconde approche est basĂ©e sur les perspectives offertes par les indications gĂ©ographiques, qui font lâobjet dâune dynamique remarquable en Inde mais qui nâont pas encore Ă©tĂ© mobilisĂ©es pour le cafĂ© de Coorg. La troisiĂšme sâappuie sur lâĂ©mergence des certifications environnementales pour le cafĂ© en Inde. Nous proposons une analyse de lâefficacitĂ© sociale et environnementale de ces trois stratĂ©gies ainsi quâune lecture des questions soulevĂ©es par lâimplication diffĂ©rentielle des acteurs porteurs et/ou usagers potentiels de ces dĂ©marches
Discovery of a mcl-PHA with unexpected biotechnical properties: the marine environment of French Polynesia as a source for PHA-producing bacteria
International audienceA library of microorganisms originating from various marine environments in French Polynesia was screened for polyhydroxyalkanoate producing bacteria. No significant connection was found between the geoâecological source of bacteria and their ability to produce polyhydroxyalkanoate. A bacterial strain designated as Enterobacter FAK 1384 was isolated from a shark jaw. When grown on coprah oil, this bacterium produces a PHA constituting of 62 mol % 3âhydroxydecanoate and lower amount of 12 mol % 3âhydroxydodecenoate and of 7.6 mol % 3âhydroxydodecanoate. These interesting properties make this mclâPHA a good candidate for further exploitations in many industrial sectors, as in film and coating manufacturing, as well as for biomedical applications
Complex stratification and layers dynamics above Marseille and suburb on Juin 26th (IOP 2B
Complex stratification and layers dynamics above Marseille and suburb on Juin 26th (IOP 2B
MOESM1 of Discovery of a mcl-PHA with unexpected biotechnical properties: the marine environment of French Polynesia as a source for PHA-producing bacteria
Additional file 1: Fig. S1. The multiple correspondence analysis performs a multivariate analysis, with categorical and quantitative variables. Two individuals are close to each other if they shared the same traits (variables). The green triangles show the presence or absence of PHA between the different associations. Isolates are shown in blue. MarSed: Marine sediment, MicroMat: Microbial mats, MarFilm: Marine film and MarAni: Marine animals. Fig. S2: The maximum-likelihood reconstruction of the 16S nuclear ribosomal DNA genotypes of Enterobacter shows the phylogenetic position of FAK1384 within the genera Enterobacter. Accession numbers are put in brackets. Node numbers indicate percentage bootstrap support from 500 replicates. Nodes without bootstrap values were supported by less than 75ĂÂ % of the replicates. Table S1: 25 out of the 70 tested isolates show a significant PHA production ability (>ĂÂ 15ĂÂ %)
Study of the boundary layer and low troposphere in the area of Marseille. Time evolution of the vertical stratification through ground remote-sensed data
Aerosols over the ESCOMPTE domain: overwhelming importance of the secondary aerosol formation
2-4 février 200
Structure, rheology, and copper-complexation of a hyaluronan-like exopolysaccharide from Vibrio
MO245 exopolysaccharide (EPS) was produced in laboratory conditions fromĂ VibrioĂ genus microorganism isolated from bacterial mats found in Moorea Island. Its structure consists of a linear tetrasaccharide repeating unit Ăą 4)-ĂÂČ-D-GlcpA-(1Ăą 4)-ñ-D-GalpNAc-(1Ăą 3)-ĂÂČ-D-GlcpNAc-(1Ăą 4)-ĂÂČ-D-GlcpA-(1Ăą containing covalently-linked 5% of glucose, galactose, and rhamnose, determined by methylation analyses and NMR spectroscopy. The molecular weight, radius of gyration (Rg) and intrinsic viscosity, [Ă·], determined by gel permeation chromatography with light scattering and viscosity detection, were 513Ăą ñù 4Ăą kDa (PDI, 1.42Ăą ñù 0.01), 6.7Ăą ñù 0.3Ăą dl/g and 56Ăą ñù 0.3Ăą nm respectively. The chelation of the EPS with copper divalent ions leads to the instantaneous formation of gels. The structural similitude proposed, based in an equal ratio of GlcA to N-acetylated sugars and in the same type of glyosidic linkages present in the repeating unit (alternated 1Ăą 3 and 1Ăą 4 linkages), is translated into analogous physicochemical properties: MO245 EPS is a flexible polyelectrolyte, with scaling exponents similar to that described for HA. This similitude opens opportunities in future drug delivery, tissue engineering, and cosmetic applications.RIAIDT, CACTUS at the University of Santiago de Compostela and in the "Manuel Rico" NMR laboratory (LMR) of the Spanish National Research Council (CSIC) were the 750âMHz and 800âMHz NMR spectra were carried out respectively. FCT/MEC for the financial support to CICECO (FCT UID /CTM /50011/2013; POCI-01-0145-FEDER-007679) and QOPNA research Unit (FCT UID/QUI/00062/2013), through national founds and co-financed by the FEDER, within the PT2020 Partnership Agreement. RNC (IF/00373/2014), CN (SFRH/BPD/100627/2014), and ASF (SFRH/BD/102471/2014) thank the FCT foundation for funding