Coastal bacterioplankton community response to diatom-derived polysaccharide microgels

Phytoplankton-derived polysaccharide microgels, including transparent exopolymer particles (TEP), are a major component of the marine organic carbon pool. Previous studies have made correlative links between phytoplankton material and bacterioplankton, and performed experiments that assess general responses to phytoplankton, yet there is a lack of direct empirical evidence of specific bacterioplankton responses to natural phytoplankton polysaccharide microgels. In this study, we used diatom produced TEP in controlled incubation experiments to determine the impact of polysaccharide microgels on a coastal bacterioplankton community. Quantification of bacterial 16S rRNA gene transcripts showed that the addition of TEP caused an increase in bacterioplankton activity. Similarly, high-throughput sequencing of RT-PCR amplified bacterial 16S rRNA gene transcripts showed that active bacterioplankton community structure and diversity also changed in response to microgels. Alteromonadales and Rhodobacterales increased in abundance in response to TEP, suggesting that both bacterioplankton taxa utilize diatom-derived microgels. However, through assessing 13C-labelled TEP uptake via RNA Stable Isotope Probing, we show that only the Alteromonadales (genus Alteromonas) assimilated the TEP carbon. This study adds utilization of diatom-derived TEP to the metabolic repertoire of the archetypal copiotrophic bacterioplankton Alteromonas, and indicates that the Rhodobacterales may utilize TEP for other purposes (e.g. attachment sites)

Transcriptome Fingerprinting Analysis: An Approach to Explore Gene Expression Patterns in Marine Microbial Communities

Microbial transcriptomics are providing new insights into the functional processes of microbial communities. However, analysis of each sample is still expensive and time consuming. A rapid and low cost method that would allow the identification of the most interesting samples for posterior in-depth metatranscriptomics analysis would be extremely useful. Here we present Transcriptome Fingerprinting Analysis (TFA) as an approach to fulfill this objective in microbial ecology studies. We have adapted the differential display technique for mRNA fingerprinting based on the PCR amplification of expressed transcripts to interrogate natural microbial eukaryotic communities. Unlike other techniques, TFA does not require prior knowledge of the mRNA sequences to be detected. We have used a set of arbitrary primers coupled with a fluorescence labeled primer targeting the poly(A) tail of the eukaryotic mRNA, with further detection of the resulting labeled cDNA products in an automated genetic analyzer. The output represented by electropherogram peak patterns allowed the comparison of a set of genes expressed at the time of sampling. TFA has been optimized by testing the sensitivity of the method for different initial RNA amounts, and the repeatability of the gene expression patterns with increasing time after sampling both with cultures and environmental samples. Results show that TFA is a promising approach to explore the dynamics of gene expression patterns in microbial communities

Microalgae biomass as an alternative ingredient in cookies: sensory, physical and chemical properties, antioxidant activity and in vitro digestibility

Microalgae can be regarded as an alternative and promising food ingredient due to their nutritional composition, richness in bioactive compounds, and because they are considered a sustainable protein source for the future. The aim of this work was to evaluate microalgae (Arthrospira platensis F & M-C256, Chlorella vulgaris Allma, Tetraselmis suecica F & M-M33 and Phaeodactylum tricornutum F & M-M40) as innovative ingredients to enhance functional properties of cookies. Two biomass levels were tested and compared to control: 2% (w/w) and 6% (w/ w), to provide high levels of algae-bioactives. The cookies sensory and physical properties were evaluated during eight weeks showing high color and texture stability. Cookies prepared with A. platensis and C. vulgaris presented significantly (p < 0.05) higher protein content compared to the control, and by sensory analysis A. platensis cookies were preferred. Besides, A. platensis also provided a structuring effect in terms of cookies texture. All microalgae-based cookies showed significantly higher (p < 0.05) total phenolic content and in vitro antioxidant capacity compared to the control. No significant difference (p < 0.05) in in vitro digestibility between microalgae cookies and the control was foundinfo:eu-repo/semantics/publishedVersio

Long-term and trans-life-cycle effects of exposure to ocean acidification in the green sea urchin Strongylocentrotus droebachiensis

Anthropogenic CO2 emissions are acidifying the world’s oceans. A growing body of evidence demonstrates that ocean acidification can impact survival, growth, development and physiology of marine invertebrates. Here, we tested the impact of long-term (up to 16 months) and trans-life-cycle (adult, embryo/larvae and juvenile) exposure to elevated pCO2 (1,200 μatm, compared to control 400 μatm) on the green sea urchin Strongylocentrotus droebachiensis. Female fecundity was decreased 4.5-fold when acclimated to elevated pCO2 for 4 months during reproductive conditioning, while no difference was observed in females acclimated for 16 months. Moreover, adult pre-exposure for 4 months to elevated pCO2 had a direct negative impact on subsequent larval settlement success. Five to nine times fewer offspring reached the juvenile stage in cultures using gametes collected from adults previously acclimated to high pCO2 for 4 months. However, no difference in larval survival was observed when adults were pre-exposed for 16 months to elevated pCO2. pCO2 had no direct negative impact on juvenile survival except when both larvae and juveniles were raised in elevated pCO2. These negative effects on settlement success and juvenile survival can be attributed to carry-over effects from adults to larvae and from larvae to juveniles. Our results support the contention that adult sea urchins can acclimate to moderately elevated pCO2 in a matter of a few months and that carry-over effects can exacerbate the negative impact of ocean acidification on larvae and juveniles

The James Webb Space Telescope Mission

Twenty-six years ago a small committee report, building on earlier studies, expounded a compelling and poetic vision for the future of astronomy, calling for an infrared-optimized space telescope with an aperture of at least $4m$. With the support of their governments in the US, Europe, and Canada, 20,000 people realized that vision as the $6.5m$ James Webb Space Telescope. A generation of astronomers will celebrate their accomplishments for the life of the mission, potentially as long as 20 years, and beyond. This report and the scientific discoveries that follow are extended thank-you notes to the 20,000 team members. The telescope is working perfectly, with much better image quality than expected. In this and accompanying papers, we give a brief history, describe the observatory, outline its objectives and current observing program, and discuss the inventions and people who made it possible. We cite detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space Telescope Overview, 29 pages, 4 figure

En musique vers le nazisme : Cabaret de Bob Fosse, poétisation à rebours de la république de Weimar

Un exemple de contrepoétisation. Tiré du roman de Christopher Isherwood Adieu Berlin, ce film, sorti en 1972, est une variante du musical américain et illustre la montée du nazisme au début des années trente, à partir de chansons de cabaret, l’esthétique musicale étant elle-même inscrite dans l’esthétique de l’image filmique, de dialogues appartenant au genre du mélodrame et d’un montage expressif, mis au service d’une évocation/dénonciation de cette période historique. L’intérêt du film tient au fait que la contrepoétisation se dévoile progressivement, suivant en cela le cheminement de la République de Weimar vers le délitement

Fontane, Effi Briest de R. W. Fassbinder : un vaste contrechamp

La littérature a souvent été présente dans l’œuvre de Fassbinder, soit sous forme d’adaptations de textes, soit à travers l’évocation d’écrivains dans ses films. En 1974, Fassbinder avait déjà porté à l’écran des pièces de théâtre comme Pionniers à Ingolstadt d’après Marie-Luise Fleisser ou Gibier de passage d’après Franz Xaver Kroetz, mais pas encore de roman. L’adaptation d’Effi Briest sera en fait son premier grand succès commercial et c’est aussi l’une des raisons pour lesquelles il en ré..

Le regard fantastique

« Comme si l’envers, le dessous de toutes les choses humaines n’était pas du merveilleux tout aussi inexplicable que ce qu’on nie, faute de l’expliquer ! » Barbey d’Aurevilly ‑ L’ensorcelée Débarquant à Toulon quelques années avant la Révolution française, une musulmane versée dans les sciences occultes et prophétesse à ses heures, se convertit à la foi chrétienne et s’installe à Marseille pour y devenir actrice. Elle prend comme amant un comte qui la quittera pour en épouser une autre. Furie..

Un blues est-allemand

Schultze gets the Blues, tout en reprenant certains thèmes favoris du cinéma allemand actuel, s’en démarque. Le film évolue à la frontière de différents genres qu’il détourne, comme le Heimatfilm, le road-movie, la comédie de mœurs, la satire sociale. La narrativité est faible, l’essentiel étant l’analyse des situations, prétexte à une réflexion critique sur l’Allemagne contemporaine. Schorr s’attache à décrire un lieu de l’Est qui n’a aucune dimension esthétique ni éthique, un non-lieu. Il s’agit d’une re-présentation, placée sous le signe de l’uniformité, qui régit, avec la tradition, les rapports sociaux locaux, entraînant l’aliénation de l’individu. Le délitement économique s’accompagne d’une dépression morale, séquelle de la réunification et de la mondialisation. Mais Schorr offre aussi une vision optimiste sur la capacité de l’homme à se régénérer, alors que la disqualification morale et esthétique des lieux filmés par le cinéma allemand contemporain n’est compensée par aucune ouverture sur un futur : au-delà de la question posée de façon récurrente, est-ce le film qui fait le lieu ou le lieu qui fait le film, Schorr franchit en permanence la frontière entre réalité et fiction afin d’offrir une réflexion sur l'appréhension de cette réalité par l’individu et sa façon de l’affronter et d’affirmer sa liberté