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Climate change is pushing species outside of their evolved tolerances. Plant populations must acclimate, adapt, or migrate to avoid extinction. However, because plants associate with diverse microbial communities that shape their phenotypes, shifts in microbial associations may provide an alternative source of climate tolerance. Here, we show that tree seedlings inoculated with microbial communities sourced from drier, warmer, or colder sites displayed higher survival when faced with drought, heat, or cold stress, respectively. Microbially mediated drought tolerance was associated with increased diversity of arbuscular mycorrhizal fungi, whereas cold tolerance was associated with lower fungal richness, likely reflecting a reduced burden of nonadapted fungal taxa. Understanding microbially mediated climate tolerance may enhance our ability to predict and manage the adaptability of forest ecosystems to changing climates.

Aims In this study, we evaluate the antimicrobial activity of bacteria isolated from marine sponges Hymeniacidon perlevis and Halichondria panicea against clinically relevant carbapenem-resistant Acinetobacter baumannii (CRAb) isolates. Methods and results We observe the inhibitory activity of 18 (out of 114) sponge-isolated bacterial strains using medium throughput solid agar overlay assays. These strains belong to the genera Lactococcus, Pseudomonas and Vagococcus. In addition, this antimicrobial activity is validated through a liquid co-cultivation challenge using an inhibitory strain of each genus. Conclusions We show the inhibitory effect of the sponge-isolated strains against clinically relevant, modern CRAb strains and characterize this antimicrobial activity as bactericidal. Significance and impact of the study A. baumannii is one of the most problematic nosocomial ESKAPE pathogens that imposes a global threat to human health, because of its increasing resistance to last-resort antibiotics. The World Health Organization has emphasized that new alternative treatments against CRAb strains are urgently needed. Our results show promising opportunities for the isolation of potentially new bactericidal compounds from sponge-isolated bacteria of the genera Lactococcus, Pseudomonas and Vagococcus to fight modern CRAb isolates and other problematic bacterial pathogens.

Objective: The study objective was to evaluate the effects of fish stocking density on the prevalence of pathogens isolated from sixty clinically healthy fishes reared under different densities in floating net-cages in Setiu lagoon, Terengganu state, Malaysia. Results : The water temperature, pH, dissolved oxygen, total dissolved solids, salinity, water clarity, depth, and coliform concentration, were all determined within the fish cages. The healthy fish samples were randomly collected from 3 sites (A, B, and C) in cages with low and high stocking densities at each site. The bacteria were isolated from the skin, gills, kidneys, and liver of each fish sample, followed by identification to species level using the VITEK-2 system. Water quality parameters showed no differences between the cages of low and high fish densities except for site C.The total number of isolates, microbial species, and the number of pathogens isolatedfrom fish revealed no significant difference between the fish stocked in low and highdensities. A total of 25 bacterial.

International audience; Lateralization is the ascendency of one side of the body or the brain to control and perform motor or perceptual functions. Light exposure during prenatal life can modulate the expression of visual lateralization (strength and direction) in a variety of species, including birds. Individual lateralization provides cognitive advantages, but the function of lateralization at the population level is less obvious. Recent studies support the hypothesis that intra-specific population-level lateralization may favour coordination between asymmetrical individuals during synergistic (cooperative) social interactions. Since cohesion requires a good coordination, one can therefore imagine that a higher alignment of lateralization within a group, by making coordination between individuals easier, may promote social cohesion. Our study investigated the effect of light on laterality and social behaviour in Japanese quail chicks (Coturnix coturnix japonica). We compared chicks coming from eggs exposed to light during incubation to chicks coming from eggs maintained in complete darkness. We expected light-exposed (LE) chicks to be more aligned than dark-incubated (DI) ones and we wanted to test whether the most aligned chicks were also the most coordinated. We assessed laterality, social motivation, synchronization and spatial cohesion within groups of LE and DI chicks. The prenatal light conditions did not affect either laterality or chicks’ social behaviour, and there was no turning bias at the group level. An absolute laterality index characterizing the alignment of chicks living together showed that the groups with the highest indices were not necessarily the groups with the greatest synchronization and spatial cohesion. This suggests that light does not consistently induce laterality in Japanese quail chicks and that the alignment of the chicks’ turning bias does not influence their social cohesion. Quails are widely used in farm industry and scientific research and better knowledge of the consequences of incubation conditions on their behavioural asymmetries and sociality could help improve their handling and welfare.

International audience; Tritium has been receiving worldwide attention, particularly because of its production and use in existing fission reactors and future nuclear fusion technologies, leading to an increased risk of release in the environment. Linking human health effects to low-dose tritium exposures presents a challenge for many reasons. Among these: biological effects strongly depend on the speciation of tritiated products and exposure pathway; large dosimetric uncertainties may exist; measurements using in vitro cell cultures generally lack a description of effects at the tissue level, while large-scale animal studies might be ethically questionable and too highly demanding in terms of resources. In this context, threedimensional models of the human airway epithelium are a powerful tool to investigate potential toxicity induced upon inhalation of radioactive products in controlled physiological conditions. In this study we exposed such a model to tritiated water (HTO) for 24 h, with a range of activity levels (up to ;33 kBq ll–1 cm–2). After the exposures, we measured cell viability, integrity of epithelial layer and pro-inflammatoryresponse at different post-exposure time-points. We also quantified tritium absorption and performed dosimetric estimates considering HTO passage through the epithelial layer, leading to reconstructed upper limits for the dose to the tissue of less than 50 cGy cumulative dose for the highest activity. Upon exposure to the highest activity, cell viability was not decreased; however, we observed a small effect on epithelial integrity and an inflammatory response persisting after seven days. These results represent a reference condition and will guide future experiments using human airway epithelium to investigate the effects of other peculiar tritiated products.

Aims Evaluation of the antibacterial activity of cultivable bacteria associated with the marine sponges Hymeniacidon perlevis and Halichondria panicea against multi-drug resistant Staphylococcus aureus. Methods and results One hundred and fourteen bacterial isolates were recovered from H. perlevis and H. panicea. Antibacterial action was demonstrated by 70% of the isolates against reference strain Staphylococcus aureus ATCC 29213 and by 31.6% against Pseudomonas aeruginosa ATCC 27853 in agar overlay assays. Antibacterial potential was further analysed against 36 multi-drug resistant hospital Staphylococcus aureus strains with diverse resistance profiles. Among the 80 isolates positive against S. aureus ATCC 29213, 76.3% were active against at least one clinical S. aureus pathogen and 73.6% inhibited one or more methicillin-resistant (MRSA) and vancomycin non-susceptible S. aureus strains. In addition, 41.3% inhibited all vancomycin non-susceptible MRSA strains. Conclusions Culturable bacteria associated to H. perlevis and H. panicea are promising sources of antibacterial compounds of great pharmaceutical interest. Significance and impact of study This study was the first to explore the antibacterial potential of culturable bacteria associated with the marine sponges H. perlevis and H. panicea against MDR bacteria. This is the first report of antibacterial activity by Aquimarina, Denitrobaculum, Maribacter and Vagococcus isolates against MDR S. aureus strains, including vancomycin non-susceptible and methicillin-resistant ones, against which new antibiotics are urgently needed.

International audience; Social cognition involves a wide array of skills that are built largely through interactions with conspecifics and therefore depend upon early social experience. Motivation for social stimuli is a key feature of social behavior and an operant conditioning task showed that isolated wild-caught adult starlings (Sturnus vulgaris) are highly motivated to access pictures of other starlings. Here, we show that hand-raised adult starlings maintained in groups of peers throughout development but without any contact with adult models were not or only poorly motivated to access pictures of conspecifics. Moreover, they did not prefer pictures of starlings to pictures of landscapes, unlike birds wild-caught as adults. These results raise questions about the role of social experience during development, particularly with adult models, in the development of social motivation and of social representation in general.

In this study, we have investigated the phylogeny and the antagonistic interactions of culturable bacteria isolated from the sea urchin Paracentrotus lividus collected from Aber and Morgat, both located in Crozon peninsula, France. Bacteria were isolated from the gastrointestinal tracts of ten specimens by using conventional culture-dependent method and then investigated by using phylogenetic analysis based on 16S rRNA gene sequence comparisons. Assays for antagonistic interactions among the bacterial strains were performed; bacteria (including at least one strain representative of each OTU identified) were screened for antimicrobial substance production. So, 367 bacterial strains were isolated on marine-agar. On the basis of morphological characteristics, 180 strains were sequenced and 94 OTUs were classified. The dominant phyla were Proteobacteria, Firmicutes and Actinobacteria, with a high abundance of the strains belonging to the genus Psychrobacter. From the antagonistic interactions assays, it could be determined that 22.7% strains were positive for at least one antagonism interaction, 18.3% of them isolated from the sea urchins collected in Morgat. We hypothesize that the bacteria isolated in this study may represent the transitory microbiota of the gastrointestinal tract of P. lividus, and that this microbiota may be related to the diet of this marine invertebrate. Furthermore, our results suggest that chemical antagonism could play a significant role in shaping the bacterial communities within gastrointestinal tract of the sea urchins. In addition, most isolated bacteria may have promising biotechnology applications.

International audience; Social influences on vocal development of young birds have been widely studied in oscine songbirds who learn to sing by vocal imitation of conspecifics, mainly male adults. In contrast, vocal development of non-vocal learners such as Galliformes is considered as being under strong genetic influence and independent of the social environment. In this study, we investigated the role of the mother on the vocal development of young Japanese quail (Coturnix coturnix japonica). We compared the vocal development of mothered and non-mothered chicks during the first 21 days of life. We analysed the structural changes of two vocalisations: a) the rally call, emitted during long-distance communication and in stressful situations, b) the contact call, emitted during short-distance communication when chicks are in visual and/or auditory contact with congeners. We showed that temporal and spectral structures of the two types of calls changed during development and differed between mothered and nonmothered chicks. These results demonstrate that maternal presence influences the vocal development of the young in the Japanese quail. Even if the adaptive value of such changes was not assessed, these results highlight that plasticity of vocalisations in species considered as non-vocal learners has been underestimated.

International audience; Oxidative transformation of Tungsten (W) nanoparticles potentially released in aqueous and biologicalmedia in case of Tokamak (nuclear fusion) Lost of Vacuum Accident (LOVA) technological breakthroughs need to be achieved before fusion become available and economicallyviable. In addition, and prior to industrial development of the fusion technology, it is worth addressing possible negative environmental and health impacts. For instance, the interactions between the plasma and refractory materials called plasma facing components (PFC) like tungsten, will generate tritiated dust. The aim of the study is to address the fate in water and biological media of W nanoparticles that might be released in case of Lost Of Vacuum Accident (LOVA). The dilution of particles in TRIS, LHC9 and pulmonary media did not strongly affect the average size of the particles while the dilution in Saline medium lead to substantial aggregation. The results proved that oxidative dissolution of W nanoparticles occurred in several aqueous/biological media (TRIS, LHC9 and Lung media) with increasing time. Fromthe different dissolution rates as a function of the tested media, it seems that the oxidative dissolutions are rate limited by diffusion in the oxidized layer surrounding the metallic core of particles. The mechanisms of dissolution involved W4Å and W6Å corroded layers prior to W6Å dissolution. Knowledge provided by these dispersion–dissolution experiments helped to determine the environmental mobility and persistence as well as the bio-durability of these tungsten nanoparticles. As dissolution has potential to influence the toxicity of particles, it is a crucial parameter to consider in the risk assessment of particles.

International audience; Laterality is the prevalence of one side of the body to perform motor acts and perceptual functions. The evolution of directional biases that are consistent across individuals of a group may have been constrained by the opportunity for asymmetric animals to interact with other asymmetric animals. If we assume that social animals have more opportunity to interact with each other than solitary animals, we could expect that the more social animals are, the more lateralized and the more aligned they are. In precocial birds, the mother is the first and most important social partner and she has a strong influence on her young’s social motivation. We therefore wondered whether she could also influence the laterality of its young. In order to see whether mothering influences the laterality of its young, we compared behaviours of non-brooded and brooded domestic chicks (Gallus gallus domesticus). We assessed both individual- and group-level laterality during the mothering period. We also measured sociality and emotivity of both types of chicks. We found that non-brooded chicks were more strongly lateralized, more social and less emotional than brooded chicks. Asymmetrical bias was also more consistent across non-brooded chicks than across brooded chicks. These results show a postnatal influence of mothering on the development of laterality in the domestic chick, and a link between laterality and sociality. Several hypotheses could explain how the mother’s presence and behaviour can modify her young’s laterality. We will have to test these hypotheses in order to uncover the mechanisms that are at play. The influence of mothering on the lateralisation of young may have implications in both individual and group performance and fitness. Studying it further may therefore help us to understand better the evolution of laterality and its potential benefits.

To provide sufficient quantities of food and feed, farming systems have to overcome limiting factors such as the nutrient depletion of arable soils. Nitrogen being the main mineral element required for plant growth, has led to the extensive use of chemical fertilizers causing nitrogen pollution of the ecosystems. This field study investigates the use of biogas residues (BRs) as biofertilizers and their contribution to the mitigation of nitrate leaching in agricultural soils, while also demonstrating the polluting nature of chemical fertilizers. Nine different fertilization treatments classified in three schemes and two nitrogen doses were tested for three consecutive years on a grassland in the Walloon Region of Belgium. Residual soil mineral nitrogen, percentage contribution of treatments in residual nitrate and agronomic performance were assessed for each fertilization treatment. The results obtained showed significant differences on treatment and scheme level regarding nitrate accumulation in the soil, with chemical fertilizers posing the highest nitrate leaching risk. BRs did not cause nitrate accumulation in the soil, and were N rate and rainfall independent, while the chemical treatments indicated a cumulative tendency under high N rate and low precipitation. Forage yield did not demonstrate statistical differences on treatment and scheme level but varied with changing precipitation, while the maximum application rate suggested a plateau. Aboveground nitrogen content was significantly higher after the application of chemical fertilizers only in the first year, while all the chemical treatments indicated a dilution effect under elevated annual rainfall. Finally, the partial substitution of chemical fertilizers by raw digestate reduced the concentration of NO 3 − in the soil without having a negative impact on the yield and N content of the biomass. These results strongly advocate for the environmental benefits of BRs over chemical fertilizers and underline their suitability as biofertilizers and substitutes for chemical fertilizers in similar agricultural systems., SCOPUS: ar.j, info:eu-repo/semantics/published

The recycling of biogas residues resulting from the anaerobic digestion of organic waste on agricultural land is among the means to reduce chemical fertilizer use and combat climate change. This in sacco decomposition study investigates (1) the potential of the granulated biogas residue fraction to provide nutrients and enhance soil carbon sequestration when utilized as exogenous organic matter in grassland soils, and (2) the impact of different nitrogen fertilizers on the organic matter decomposition and nutrient release processes. The experiment was conducted in two permanent grasslands of the Greater Region over one management period using rooibos tea as a comparator material. The decomposition and chemical changes of the two materials after incubation in the soil were assessed by measuring the mass loss, total carbon and nitrogen status, and fibre composition in cellulose, hemicellulose and lignin. Overall, after the incubation period, granulated biogas residue maintained up to 68% of its total mass, organic matter and total carbon; increased its content in recalcitrant organic matter by up to 45% and released 45% of its total nitrogen. Granulated biogas residue demonstrated resilience and a higher response uniformity when exposed to different nitrogen fertilizers, as opposed to the comparator material of rooibos tea. However, the magnitude of fertilizer-type effect varied, with ammonium nitrate and the combinatorial treatment of raw biogas residue mixed with urea leading to the highest organic matter loss from the bags. Our findings suggest that granulated biogas residue is a biofertilizer with the potential to supply nutrients to soil biota over time, and promote carbon sequestration in grassland soils, and thereby advance agricultural sustainability while contributing to climate change mitigation.

International audience; Inhalation is the most frequent route of unintentional exposure to nanoparticles (NPs). Our aim was to quantify the translocation of different metallic NPs across human bronchial epithelial cells and to determine the factors influencing this translocation. Calu-3 cells forming a tight epithelial barrier when grown on a porous membrane in a two compartment chamber were exposed to fluorescently labelled NPs to quantify the NP translocation. NP translocation and uptake by cells were also studied by confocal and transmission electron microscopy. Translocation was characterized according to NP size (16, 50, or 100 nm), surface charge (negative or positive SiO2), composition (SiO2 or TiO2), presence of proteins or phospholipids and in an inflammatory context. Our results showed that NPs can translocate through the Calu-3 monolayer whatever their composition (SiO2 or TiO2), but this translocation was increased for the smallest and negatively charged NPs. Translocation was not associated with an alteration of the integrity of the epithelial monolayer, suggesting a transcytosis of the internalized NPs. By modifying the NP corona, the ability of NPs to cross the epithelial barrier differed depending on their intrinsic properties, making positively charged NPs more prone to translocate. NP translocation can be amplified by using agents known to open tight junctions and to allow paracellular passage. NP translocation was also modulated when mimicking an inflammatory context frequently found in the lungs, altering the epithelial integrity and inducing transient tight junction opening. This in vitro evaluation of NP translocation could be extended to other inhaled NPs to predict their biodistribution.

Polluted environments are a reservoir of microbial species able to degrade or to convert pollutants to harmless compounds. The proper management of microbial resources requires a comprehensive characterization of their genetic pool to assess the fate of contaminants and increase the efficiency of bioremediation processes. Metagenomics offers appropriate tools to describe microbial communities in their whole complexity without lab-based cultivation of individual strains. After a decade of use of metagenomics to study microbiomes, the scientific community has made significant progress in this field. In this review, we survey the main steps of metagenomics applied to environments contaminated with organic compounds or heavy metals. We emphasize technical solutions proposed to overcome encountered obstacles. We then compare two metagenomic approaches, i.e. library-based targeted metagenomics and direct sequencing of metagenomes. In the former, environmental DNA is cloned inside a host, and then clones of interest are selected based on (i) their expression of biodegradative functions or (ii) sequence homology with probes and primers designed from relevant, already known sequences. The highest score for the discovery of novel genes and degradation pathways has been achieved so far by functional screening of large clone libraries. On the other hand, direct sequencing of metagenomes without a cloning step has been more often applied to polluted environments for characterization of the taxonomic and functional composition of microbial communities and their dynamics. In this case, the analysis has focused on 16S rRNA genes and marker genes of biodegradation. Advances in next generation sequencing and in bioinformatic analysis of sequencing data have opened up new opportunities for assessing the potential of biodegradation by microbes, but annotation of collected genes is still hampered by a limited number of available reference sequences in databases. Although metagenomics is still facing technical and computational challenges, our review of the recent literature highlights its value as an aid to efficiently monitor the clean-up of contaminated environments and develop successful strategies to mitigate the impact of pollutants on ecosystems.

The microbial potential for toluene degradation within sediments from a tar oil-contaminated site in Flingern, Germany, was assessed using a metagenomic approach. High molecular weight environmental DNA from contaminated sediments was extracted, purified, and cloned into fosmid and BAC vectors and transformed into Escherichia coli. The fosmid library was screened by hybridization with a PCR amplicon of the α-subunit of the toluene 4-monooxygenase gene to identify genes and pathways encoding toluene degradation. Fourteen clones were recovered from the fosmid library, among which 13 were highly divergent from known tmoA genes and several had the closest relatives among Acinetobacter species. The BAC library was transferred to the heterologous hosts Cupriavidus metallidurans (phylum Proteobacteria) and Edaphobacter aggregans (phylum Acidobacteria). The resulting libraries were screened for expression of toluene degradation in the non-degradative hosts. From expression in C. metallidurans, three novel toluene monooxygenase-encoding operons were identified that were located on IncP1 plasmids. The E. aggregans-hosted BAC library led to the isolation of a cloned genetic locus putatively derived from an Acidobacteria taxon that contained genes involved in aerobic and anaerobic toluene degradation. These data suggest the important role of plasmids in the spread of toluene degradative capacity and indicate putative novel tmoA genes present in this hydrocarbon-polluted environment.

Although antibiotic-resistant pathogens pose a significant threat to human health, the environmental reservoirs of the resistance determinants are still poorly understood. This study reports the detection of resistance genes (ermB, mecA, mupA, qnrA, qnrB and tetL) to antibiotics among certain culturable and unculturable bacteria associated with the marine sponge Petromica citrina. The antimicrobial activities elicited by P. citrina and its associated bacteria are also described. The results indicate that the marine environment could play an important role in the development of antibiotic resistance and the dissemination of resistance genes among bacteria., SCOPUS: ar.j, info:eu-repo/semantics/published

[Departement_IRSTEA]Eaux [TR1_IRSTEA]BELCA; National audience; L’évaluation de la qualité des environnements fortement anthropisés, tel que le bassin de la Seine, et donc assujettis à des apports chroniques très complexes, constitue un véritable challenge et doit s’appuyer conjointement sur des analyses chimiques du milieu et les réponses du biote face à cette pression. La présente étude propose l’intégration et la synthèse d’un jeu de données pluridisciplinaire varié acquis lors du suivi de trois sites-ateliers le long de la Seine (à l’amont et à l’aval de Paris) au cours de quatre campagnes étalées sur une année, dans le cadre du programme PIREN-Seine (Phase 6). L’analyse repose sur l’application de l’approche « Weight-of-Evidence » consistant à examiner quatre volets ou lines of evidence combinant analyses chimiques du milieu (eau et sédiment), biodisponibilité des contaminants (bioaccumulation) et mesures de biomarqueurs chez des gammares exposés in situ, et réponses de tests de toxicité en laboratoire. Les résultats de chaque LOE reflètent parfaitement le gradient anthropique de la zone d’étude avec des niveaux de contaminations et des perturbations biologiques croissants de l’amont à l’aval de Paris. En se basant sur la moyenne annuelle, le risque environnemental global a pu être classé comme « modéré » pour le site amont et « sévère » pour les deux sites aval. L’analyse a également permis de mettre en évidence une certaine variabilité saisonnière, identifiant la campagne hivernale comme la moins fortement impactée. Le modèle a notamment été affiné par l’utilisation de valeurs de référence et de seuils de réponses issus d’études menées à large échelle géographique et intégrant certains facteurs confondants. La démarche appliquée ici s’est avérée très adaptée et performante, et pourrait représenter un outil d’aide à la décision d’un intérêt indéniable pour les différents acteurs environnementaux dans le cadre d’une analyse du risque environnemental.

The Acidobacteria phylum is of high ecological interest. Its members are ubiquitous and particularly abundant in soils but many are recalcitrant to cultivation in the laboratory. Thus, the ability of Acidobacteria to capture and maintain plasmids remains largely unexplored. In this work we tested the transfer and the stability of (i) the PromA plasmid pMOL98 and (ii) the IncQ plasmid pKT230 to the acidobacterial strain Edaphobacter aggregans DSM 19364. To this end quantitative conjugation assays were performed and transconjugants were scored for plasmid-borne antibiotic selection markers. The tested plasmids were transferred and maintained in the new host. Plasmid pMOL98 was more stable than pKT230 in Ed. aggregans in the absence of positive selection. Thus, from an ecological point of view, we have extended the host range of PromA and IncQ plasmids for the first time to an acidobacterial strain. Furthermore, we have uncovered the potential of Acidobacteria to capture as-yet-unknown plasmids and to foster the development of new cloning and expression systems for the exploitation of biotechnologically valuable soil resources.

The dynamic of a community of 20 bacterial strains isolated from river water was followed in R2 broth and in autoclaved river water medium for 27 days in batch experiments. At an early stage of incubation, a fast-growing specialist strain, Acinetobater sp. dominated the community in both media. Later on, the community composition in both media diverged but was highly reproducible across replicates. In R2, several strains previously reported to degrade multiple simple carbon sources prevailed. In autoclaved river water, the community was more even and became dominated by several strains growing faster or exclusively in that medium. Those strains have been reported in the literature to degrade complex compounds. Their growth rate in the community was 1.5- to 7-fold greater than that observed in monoculture. Furthermore, those strains developed simultaneously in the community. Together, our results suggest the existence of cooperative interactions within the community incubated in autoclaved river water., SCOPUS: ar.j, info:eu-repo/semantics/published

α-Chloro-, bromo- and iodoenamines, which are readily prepared from the corresponding isobutyramides have been found to be excellent reagents for the transformation of a wide variety of alcohols or carboxylic acids into the corresponding halides. Yields are high and conditions are very mild thus allowing for the presence of sensitive functional groups. The reagents can be easily tuned allowing therefore the selective monohalogenation of polyhydroxylated molecules. The scope and chemoselectivity of the reactions have been studied and reaction mechanisms have been proposed.

Volatile fatty acids (VFAs) are increasingly viewed as platform substances for the production of sustainable biofuels and green chemicals. Optimising the acidogenic fermentation requires determining which environmental parameters (temperature, pH, substrate, inoculum, etc) have the largest impact on the metabolite profile. The present study investigates the influence of substrate and mixed inoculum origin. Nine combinations of three complex lignocellulosic substrates and three different mixed inocula were monitored under batch conditions (35 °C; pH 6.5; triplicates, monitoring of pH, soluble COD and VFAs) during 30 days. All nine combinations led to a significantly different fermentation profile, and each combination represented a unique situation. The metabolite profiles were highly reproducible within each substrate–inoculum combination. The substrate COD conversion yield to VFAs was up to 64% (average 31%). VFAs represented most (between 61 and 98%) of the soluble COD. Acetic, propionic and butyric acids were always the major VFAs.

Marine sponges (phylum Porifera) are well known to harbour a complex and diverse bacterial community. Some of these sponge-associated bacteria have been shown to be the real producers of secondary metabolites with a wide range of activities from antimicrobials to anticancer agents. Previously, we revealed that the strain Pseudomonas fluorescens H41 isolated from the sponge Haliclona sp. (collected at the coast of Rio de Janeiro, Brazil) showed a strong antimicrobial activity against clinical and marine bacteria. Thus, in this study the genes involved in the antimicrobial activity of P. fluorescens H41 were identified. To this end, a library of mutants was generated via miniTnphoA3 transposon mutagenesis and the resulting clones were characterized for their antimicrobial activity. It was demonstrated that genes involved in the biosynthesis of the pyoverdine siderophore are related to the inhibitory activity of P. fluorescens H41. Therefore, this strain might play an important role in the biocontrol of the host sponge.

Inhalation is the most frequent route of unintentional exposure to nanoparticles (NPs). Our aim was to compare different in vitro models of human lung epithelial monolayers for their suitability to assess the translocation of 50 nm fluorescently labelled silica NPs (50 nm-SiO 2 -FITC-NPs). Human bronchial epithelial cell lines NCI-H292 and Calu-3 as well as human alveolar cell line A549 were seeded onto Transwell filters (TF) separating the well into an apical and a basal compartment. Measurements of the transepithelial electric resistance and monitoring the paracellular transport of a fluorescent marker (Lucifer Yellow) have shown that only Calu-3 cells formed a tight epithelium. In the absence of cells 4% of the initially applied NP concentration was found to cross the TF but the majority remained trapped inside the filter. After 24 h of treatment, 50 nm-SiO 2 -FITC-NPs were taken up by all cell types but their translocation was inversely correlated to the efficiency to prevent LY passage: translocation represented 3% of the initially apically applied NP concentration for Calu-3 cells, 9% for NCI-H292 cells and 35% for A549 cells. In conclusion, 50 nm-SiO 2 -FITC-NPs can cross different bronchial epithelial barriers, but the Calu-3 cell line appears to be the most relevant model for studying NP translocation.

Microbial communities play a key role in water self-purification. They are primary drivers of biogenic element cycles and ecosystem processes. However, these communities remain largely uncharacterized. In order to understand the diversity-heterotrophic activity relationship facing sole carbon sources, we assembled a synthetic community composed of 20 'typical' freshwater bacterial species mainly isolated from the Zenne River (Belgium). The carbon source utilization profiles of each individual strain and of the mixed community were measured in Biolog Phenotype MicroArrays PM1 and PM2A microplates that allowed testing 190 different carbon sources. Our results strongly suggest interactions occurring between our planktonic strains as our synthetic community showed metabolic properties that were not displayed by its single components. Finally, the catabolic performances of the synthetic community and a natural community from the same sampling site were compared. The synthetic community behaved like the natural one and was therefore representative of the latter in regard to carbon source consumption.

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.; International audience; Songbirds are an excellent model for investigating the perception of learned complex acoustic communication signals. Male European starlings (Sturnus vulgaris) sing throughout the year distinct types of song that bear either social or individual information. Although the relative importance of social and individual information changes seasonally, evidence of functional seasonal changes in neural response to these songs remains elusive. We thus decided to use in vivo functional magnetic resonance imaging (fMRI) to examine auditory responses of male starlings that were exposed to songs that convey different levels of information (species-specific and group identity or individual identity), both during (when mate recognition is particularly important) and outside the breeding season (when group recognition is particularly important). We report three main findings: (1) the auditory area caudomedial nidopallium (NCM), an auditory region that is analogous to the mammalian auditory cortex, is clearly involved in the processing/categorization of conspecific songs; (2) season-related change in differential song processing is limited to a caudal part of NCM; in the more rostral parts, songs bearing individual information induce higher BOLD responses than songs bearing species and group information, regardless of the season; (3) the differentiation between songs bearing species and group information and songs bearing individual information seems to be biased toward the right hemisphere. This study provides evidence that auditory processing of behaviorally-relevant (conspecific) communication signals changes seasonally, even when the spectro-temporal properties of these signals do not change.

International audience; Birdsong, like speech, is a learned behaviour whose critical function is to communicate with others and whose development critically depends on social influences. Song learning is a complex phenomenon that involves not only the development of species-specific vocalisations, but also the development of the ability to organise these vocalisations and to use them in an appropriate context. Although the fact that interactions with adult experienced models are essential for song production to develop properly has been well established, far less is known about song perception and processing. The fact that songbirds learn to vocalise and to use their vocalisations selectively through interactions with adults questions whether such interactions are also required for songbirds to perceive and process their vocalisations selectively and whether social interactions may shape song perception and processing as they shape song production. In order to address these questions, our team uses an original neuroethological approach to study the neural bases of song behaviour in a highly social songbird species: the European starlings. We provide here a synthesis of the results we have obtained using this approach over the last decade. Our results show that direct social experience with adult experienced models not only shapes song behaviour but also shapes these songbirds' brains and their ability to perceive and to process acoustic signals whose communicative value, as well as their acoustic structure, have to be learned.

International audience; Whether anesthesia impacts brain sensory processing is a highly debated and important issue. There is a general agreement that anesthesia tends to diminish neuronal activity, but its potential impact on neuronal " tuning " is still an open question. Here we show, based on electrophysiological recordings in the primary auditory area of a female songbird, that anesthesia induces neuronal responses towards biologically irrelevant sounds and prevents the seasonal neuronal tuning towards functionally relevant species-specific song elements. These results demonstrate a clear impact of anesthesia on sensory and cognitive processes. They demonstrate the need to better understand the actions of these drugs. They also open new lines of thought on the differentiation between sensory basic processing and the brain processing of behaviorally relevant items that require high vigilance.

Sponges offer an excellent model to investigate invertebrate–microorganism interactions. Furthermore, bacteria associated with marine sponges represent a rich source of bioactive metabolites. The aim of this study was to characterize the bacteria inhabiting a genus of sponges, Oscarella, and their potentiality for antimicrobial production. Bacterial isolates were recovered from different Oscarella specimens, among which 337 were phylogenetically identified. The culturable community was dominated by Proteobacteria and Firmicutes, and Vibrio was the most frequently isolated genus, followed by Shewanella. When tested for antimicrobial production, bacteria of the 12 genera isolated were capable of producing antimicrobial substances. The majority of strains were involved in antagonistic interactions and inhibitory activities were also observed against bacteria of medical importance. It was more pronounced in some isolated genera (Acinetobacter, Bacillus, Photobacterium, Shewanella and Vibrio). These findings suggest that chemical antagonism could play a significant role in shaping bacterial communities within Oscarella, a genus classified as low-microbial abundance sponge. Moreover, the identified strains may contribute to the search for new sources of antimicrobial substances, an important strategy for developing therapies to treat infections caused by multidrug-resistant bacteria. This study was the first to investigate the diversity and antagonistic activity of bacteria isolated from Oscarella spp. It highlights the biotechnological potential of sponge-associated bacteria.

Polyketides are structurally diverse secondary metabolites, many of which have antibiotic or anticancer activity. Type I modular polyketide synthase (PKS) genes are typically large and encode repeating enzymatic domains that elongate and modify the nascent polyketide chain. A fosmid metagenomic library constructed from an agricultural soil was arrayed and the macroarray was screened for the presence of conserved ketosynthase [β-ketoacyl synthase (KS)] domains, enzymatic domains present in PKSs. Thirty-four clones containing KS domains were identified by Southern hybridization. Many of the KS domains contained within metagenomic clones shared significant similarity to PKS or nonribosomal peptide synthesis genes from members of the Cyanobacteria or the Proteobacteria phyla. However, analysis of complete clone insert sequences indicated that the blast analysis for KS domains did not reflect the true phylogenetic origin of many of these metagenomic clones that had a %G+C content and significant sequence similarity to genes from members of the phylum Acidobacteria. This conclusion of an Acidobacteria origin for several clones was further supported by evidence that cultured soil Acidobacteria from different subdivisions have genetic loci closely related to PKS domains contained within metagenomic clones, suggesting that Acidobacteria may be a source of novel polyketides. This study also demonstrates the utility of combining data from culture-dependent and -independent investigations in expanding our collective knowledge of microbial genomic diversity.

We designed an oligonucleotide microarray using probe sequences based upon a phylogenetic analysis of 16S rRNA genes recovered from members of the bacterial division Acidobacteria. A total of 42,194 oligonucleotide probes targeting members of the Acidobacteria division at multiple phylogenetic levels were included on a high-density microarray. Positive control hybridizations revealed a linear relationship between hybridization signal and template concentration, and a substantial decrease in non-specific hybridization was achieved through the addition of 2.5 M betaine to the hybridization buffer. A mean hybridization signal value was calculated for each Acidobacteria lineage, with the resultant lineage-specific hybridization data revealing strong predictive value for the positive control hybridizations. The Acidobacteria phylochip was then used to evaluate Acidobacteria rRNA genes from a Wisconsin soil and within a soil clay fraction. The Acidobacteria hybridization profile revealed the predominance of Acidobacteria subdivisions four and six, and also suggested a decrease in the abundance of subdivision six relative to subdivision four in the soil clay fraction. The change in relative abundance of these subdivisions in a soil clay fraction was supported by data from quantitative PCR. These results support the utility of a phylogenetic microarray in revealing changes in microbial population-level distributions in a complex soil microbial assemblage. (C) 2010 Elsevier Ltd. All rights reserved.

Sustainable development requires the promotion of environmental management and a constant search for new technologies to treat a wide range of aquatic and terrestrial habitats contaminated by increasing anthropogenic activities. Bioremediation, i.e. the elimination of natural or xenobiotic pollutants by living organisms, is an environmentally friendly and cost-effective alternative to physico-chemical cleanup options. However, the strategy and outcome of bioremediation in open systems or confined environments depend on a variety of physico-chemical and biological factors that need to be assessed and monitored. In particular, microorganisms are key players in bioremediation applications, yet their catabolic potential and their dynamics in situ remain poorly characterized. To perform a comprehensive assessment of the biodegradative potential of a contaminated site and efficiently monitor changes in the structure and activities of microbial communities involved in bioremediation processes, sensitive, fast and large-scale methods are needed. Over the last few years, the scientific literature has revealed the progressive emergence of genomic high-throughput technologies in environmental microbiology and biotechnology. In this review, we discuss various high--throughput techniques and their possible--or already demonstrated-application to assess biotreatment of contaminated environments.

Marine sponges are sessile and filter-feeding organisms that harbor dense and diverse microbial communities of considerable ecological and biotechnological importance. They represent an important target for the study of bacterial interactions in marine ecosystems. The purpose of this study was to examine the frequency of antagonistic interactions among the culturable microbial communities associated with sponges from the Brazilian coast. The specimens were collected over six years at Cagarras Archipelago, Praia Vermelha Beach and Urca square, Rio de Janeiro State, SE Brazil. Fifty-six bacterial isolates representing four classes of cultivable sponge-associated bacteria were studied for their ability to produce inhibitory substances. Antagonistic interactions occurred among isolates from both, the same and different sponge species. Most isolates (98.2%) were able to inhibit growth of at least one indicator bacterium. In contrast, there were few antagonistic interactions among bacteria obtained from the same sponge specimen. Our results suggest that chemical antagonism could play a significant role in shaping the bacterial communities within sponge tissues.

International audience; Because of their sophisticated vocal behaviour, their social nature, their high plasticity and their robustness, starlings have become an important model species that is widely used in studies of neuroethology of song production and perception. Since Magnetic Resonance Imaging (MRI) represents an increasingly relevant tool for comparative neuroscience, a 3-dimensional MRI-based atlas of the starling brain becomes essential. Using multiple imaging protocols we delineated several sensory systems as well as the song control system. This starling brain atlas can easily be used to determine the stereotactic location of identified neural structures at any angle of the head. Additionally, the atlas is useful to find the optimal angle of sectioning for slice experiments, stereotactic injections and electrophysiological recordings. The starling brain atlas is freely available for the scientific community.

The Seine river watershed (France) is a deeply anthropogenically impacted area, due to the high population density, intense industrial activities and intensive agriculture. The water quality and ecological functioning of the different rivers of the Seine drainage network have been extensively studied during the last fifteen years within the framework of a large French multidisciplinary scientific program (PIREN Seine program). This paper presents a synthesis of the main data gained in the scope of this program concerning the microbiological water contamination of the rivers of the Seine drainage network. The more common indicator of fecal contamination (fecal coliforms) was mainly used; some complementary works used E. coli and intestinal enterococci as alternative fecal indicators. Point sources (outfall of wastewater treatment plants) and non point sources (surface runoff and soil leaching) of fecal pollution to the rivers of the watershed were quantified. Results showed that, at the scale of a large urbanised watershed as the Seine basin, the input of fecal micro-organisms by non-point sources is much lower than the inputs by point sources. However, the local impact of diffuse non-human sources (especially surface runoff of pastured fields) can be of major importance on the microbiological quality of small headwater rivers. Fecal contamination of the main rivers of the Seine watershed (Seine, Marne, Oise rivers) was studied showing high level of microbiological pollution when compared to European guidelines for bathing waters. The strong negative impact of treated wastewater effluents outfall on the microbiological quality of receiving rivers was observed in different areas of the watershed. Once released in rivers, culturable fecal bacteria disappeared relatively rapidly due to mortality (protozoan grazing, lysis) or loss of culturability induced by stress conditions (sunlight effect, nutrient concentration, temperature). Mortality rates of E. coli were studied in different types of rivers within the watershed showing, in summer conditions, no major difference in the mortality rates in small and large rivers. As a result of these studies, a module describing the dynamics of fecal bacteria has been developed and embedded within a hydro-ecological model describing the functioning of the rivers of the whole watershed (the SENEQUE model). Once validated, such a model can be used for testing predictive scenarios and thus can be a very useful tool for the management of microbiological water quality at the scale of the whole basin.

Background Poorly soluble cobalt (II, III) oxide particles (Co3O4P) are believed to induce in vitro cytotoxic effects via a Trojan-horse mechanism. Once internalized into lysosomal and acidic intracellular compartments, Co3O4P slowly release a low amount of cobalt ions (Co2+) that impair the viability of in vitro cultures. In this study, we focused on the genotoxic potential of Co3O4P by performing a comprehensive investigation of the DNA damage exerted in BEAS-2B human bronchial epithelial cells. Results Our results demonstrate that poorly soluble Co3O4P enhanced the formation of micronuclei in binucleated cells. Moreover, by comet assay we showed that Co3O4P induced primary and oxidative DNA damage, and by scoring the formation of γ-H2Ax foci, we demonstrated that Co3O4P also generated double DNA strand breaks. Conclusions By comparing the effects exerted by poorly soluble Co3O4P with those obtained in the presence of soluble cobalt chloride (CoCl2), we demonstrated that the genotoxic effects of Co3O4P are not simply due to the released Co2+ but are induced by the particles themselves, as genotoxicity is observed at very low Co3O4P concentrations.