Efficacy of a Mycotoxin Binder against Dietary Fumonisin, Deoxynivalenol, and Zearalenone in Rats

It was hypothesized that a mycotoxin binder, Grainsure E, would inhibit adverse effects of a mixture of fumonisin B1, deoxynivalenol, and zearalenone in rats. For 14 and 28 days, 8–10 Sprague–Dawley rats were fed control diet, Grainsure E (0.5%), toxins (7 μg fumonisin B1/g, 8 μg of deoxynivalenol/g and 0.2 μg of zearalenone/g), toxins (12 μg of fumonisin B1/g, 9 μg of deoxynivalenol/g, and 0.2 μg of zearalenone/g + Grainsure E), or pair-fed to control for food intake of toxin-fed rats. After 28 days, decreased body weight gain was prevented by Grainsure E in toxin-fed female rats, indicating partial protection against deoxynivalenol and fumonisin B1. Two effects of fumonisin B1 were partly prevented by Grainsure E in toxin-fed rats, increased plasma alanine transaminase (ALT) and urinary sphinganine/sphingosine, but sphinganine/sphingosine increase was not prevented in females at the latter time point. Grainsure E prevented some effects of fumonisin B1 and deoxynivalenol in rats

Reconciliation of the carbon budget in the ocean’s twilight zone

Photosynthesis in the surface ocean produces approximately 100 gigatonnes of organic carbon per year, of which 5 to 15 per cent is exported to the deep ocean1, 2. The rate at which the sinking carbon is converted into carbon dioxide by heterotrophic organisms at depth is important in controlling oceanic carbon storage3. It remains uncertain, however, to what extent surface ocean carbon supply meets the demand of water-column biota; the discrepancy between known carbon sources and sinks is as much as two orders of magnitude4, 5, 6, 7, 8. Here we present field measurements, respiration rate estimates and a steady-state model that allow us to balance carbon sources and sinks to within observational uncertainties at the Porcupine Abyssal Plain site in the eastern North Atlantic Ocean. We find that prokaryotes are responsible for 70 to 92 per cent of the estimated remineralization in the twilight zone (depths of 50 to 1,000 metres) despite the fact that much of the organic carbon is exported in the form of large, fast-sinking particles accessible to larger zooplankton. We suggest that this occurs because zooplankton fragment and ingest half of the fast-sinking particles, of which more than 30 per cent may be released as suspended and slowly sinking matter, stimulating the deep-ocean microbial loop. The synergy between microbes and zooplankton in the twilight zone is important to our understanding of the processes controlling the oceanic carbon sink

Dégradation de la matière organique dissoute de haut poids moléculaire par les communautés procaryotiques des zones méso- et bathypélagique

Ce travail a pour objectif principal l'étude des interactions entre les compartiments procaryotiques des zones méso- et bathypélagique avec les différentes fractions du carbone organique dissout (DOC) océanique. Des mesures d'assimilation de monomères (3H-Glucose), de dégradation de molécules complexes (3H-EPS et HMW-DOC), et de production hétérotrophe procaryotique (PHP/3H-Leucine) ont été réalisées le long de la colonne d'eau en Mer Méditerranée Nord Occidentale (Golfe du Lion, sites DYFAMED, ANTARES) et en Océan Atlantique Nord-Est (site PAP). Au cours des ces études, toutes les mesures réalisées au-delà de 1000 m de profondeur ont été effectuées dans des conditions in situ de haute pression hydrostatique (> à 10 MPa, HP) et comparées à des mesures réalisées sous pression atmosphérique (0,1 MPa, ATM). Cette double mesure détermine le rôle de la pression hydrostatique sur les activités microbiennes profondes via un rapport Pe pour pressure effect (= mesure HP / mesure ATM). Les résultats démontrent que les activités microbiennes mesurées en conditions HP sont plus importantes qu'en conditions ATM en période de stratification des eaux, (Pe moyen de 4,01, n=120), et confirment la capacité des procaryotes du domaine océanique profond à dégrader des molécules organiques complexes. Par ailleurs et à une échelle cellulaire, les populations métaboliquement actives du milieu profond dégradent les 3H-EPS à une vitesse 6 fois plus rapide que leur homologue de surface, indiquant la capacité des procaryotes autochtones profonds à dégrader des molécules plus complexes en conditions de haute pression.This main objective of this work is the study of interactions between prokaryotic compartments of meso-and bathypelagic zones with different size classes of dissolved organic carbon (DOC). Several measurements of monomers assimilation (3H-Glucose), of complex molecules degradation (3H-EPS and HMW-DOC) and prokaryotic heterotrophic production were realized through the water column of NW Mediterranean Sea (Gulf of Lion, DYFAMED and ANTARES station) and NE Atlantic Ocean (PAP site). During these studies, all measurements realized below 1000 m depth, were carry out under in situ condition of hydrostatic pressure (> 10 MPa, HP) and compared to their decompressed counterpart measurements, realized at atmospheric pressure (0.1 MPa, ATM). These coupled measurements determine the role of hydrostatic pressure on deep sea microbial activity following the Pressure effect (Re) ration (=HP measurement / ATM measurement). The results show that microbial activities measured under HP condition during stratified water period, were more important than those measured under ATM condition (mean Pe = 4.01, n=120), and confirm the abilities of deep sea prokaryotes to degrade complex organic molecules. Moreover, the cell-specific activity of deep sea prokaryotes in 3H-EPS degradation are 6 time more active than the surface, indicating the ability of autochthonous deep sea prokaryotes to degrade complex molecules under high conditions of pressure

Dégradation de la matière organique dissoute de haut poids moléculaire par les communautés procaryotiques des zones méso- et bathypélagique

Ce travail a pour objectif principal l'étude des interactions entre les compartiments procaryotiques des zones méso- et bathypélagique avec les différentes fractions du carbone organique dissout (DOC) océanique. Des mesures d'assimilation de monomères (3H-Glucose), de dégradation de molécules complexes (3H-EPS et HMW-DOC), et de production hétérotrophe procaryotique (PHP/3H-Leucine) ont été réalisées le long de la colonne d'eau en Mer Méditerranée Nord Occidentale (Golfe du Lion, sites DYFAMED, ANTARES) et en Océan Atlantique Nord-Est (site PAP). Au cours des ces études, toutes les mesures réalisées au-delà de 1000 m de profondeur ont été effectuées dans des conditions in situ de haute pression hydrostatique (> à 10 MPa, HP) et comparées à des mesures réalisées sous pression atmosphérique (0,1 MPa, ATM). Cette double mesure détermine le rôle de la pression hydrostatique sur les activités microbiennes profondes via un rapport Pe pour pressure effect (= mesure HP / mesure ATM). Les résultats démontrent que les activités microbiennes mesurées en conditions HP sont plus importantes qu'en conditions ATM en période de stratification des eaux, (Pe moyen de 4,01, n=120), et confirment la capacité des procaryotes du domaine océanique profond à dégrader des molécules organiques complexes. Par ailleurs et à une échelle cellulaire, les populations métaboliquement actives du milieu profond dégradent les 3H-EPS à une vitesse 6 fois plus rapide que leur homologue de surface, indiquant la capacité des procaryotes autochtones profonds à dégrader des molécules plus complexes en conditions de haute pression.This main objective of this work is the study of interactions between prokaryotic compartments of meso-and bathypelagic zones with different size classes of dissolved organic carbon (DOC). Several measurements of monomers assimilation (3H-Glucose), of complex molecules degradation (3H-EPS and HMW-DOC) and prokaryotic heterotrophic production were realized through the water column of NW Mediterranean Sea (Gulf of Lion, DYFAMED and ANTARES station) and NE Atlantic Ocean (PAP site). During these studies, all measurements realized below 1000 m depth, were carry out under in situ condition of hydrostatic pressure (> 10 MPa, HP) and compared to their decompressed counterpart measurements, realized at atmospheric pressure (0.1 MPa, ATM). These coupled measurements determine the role of hydrostatic pressure on deep sea microbial activity following the Pressure effect (Re) ration (=HP measurement / ATM measurement). The results show that microbial activities measured under HP condition during stratified water period, were more important than those measured under ATM condition (mean Pe = 4.01, n=120), and confirm the abilities of deep sea prokaryotes to degrade complex organic molecules. Moreover, the cell-specific activity of deep sea prokaryotes in 3H-EPS degradation are 6 time more active than the surface, indicating the ability of autochthonous deep sea prokaryotes to degrade complex molecules under high conditions of pressure