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24 results on '"Gosewinkel, Ulrich Bay"'

2. Effects of glyphosate of the intestinal microbiota

Author

Nielsen, Lene Nørby, Roager, Henrik Munch, Casas, Mònica Escolà, Frandsen, Henrik L., Gosewinkel, Ulrich Bay, Bester, Kai, Licht, Tine Rask, Hendriksen, Niels Bohse, and Iain Bahl, Martin

Subjects
SDG 3 - Good Health and Well-being
Abstract

The intestinal bacterial community is now recognized as an important factor for health and implicated in numerous states of disease. Despite the fairly extensive regulatory demands for risk assessment of pesticides in relation to human exposure, there is currently very little knowledge related to potential effects on the gut microbiota. It has however recently been speculated that glyphosate based herbicides may affect the gut microbiota of humans and animal husbandry due to inhibition of the Shikimate pathway in bacteria causing loss of aromatic amino acid synthesis and thus growth inhibition. In this study Sprague Dawley rats were exposed to glyphosate at 5x and 50x the acceptable daily intake (ADI) for humans. Profiling of the bacterial community and aromatic amino acids and their downstream metabolites was performed on intestinal samples obtained after two weeks of oral dossing. The results suggest that glyphosate had very limited effects on bacterial community composition even at the highest exposure concentration. Also relatively high concentrations of aromatic amino acids were measured in the intestine of the animals. The data show that glyphosate inhibits bacterial growth in minimal medium but this inhibitory effect is relieved in the presence of aromatic amino acids in the growth medium. Results from the animal trial therefor suggest that sufficient levels of aromatic amino acids are present in the rat intestine to alleviate the need for bacterial synthesis and thus prevent an antimicrobial effect of glyphosate in vivo.PrefaceThis report is written as an extended summary of the scientific work conducted during the PestiGut project “Tarmmikrobiota som følsom indikator for biologisk relevante restkoncentrationer af kemiske pesticider i fødevarer eksemplificeret ved glyphosat (Roundup®)”. The report includes an introduction to the area, overview of methods, main results and conclusions. For a more detailed presentation of the work please refer to the accompanying scientific manuscript entitled: “Glyphosate has limited short-term effects on commensal bacterial community composition in the gut environment due to sufficient aromatic amino acid levels” 1.

Published
2021

4. Pilotprojekt - In situ test af stimuleret aerob nedbrydning til oprensning af pesticidpunktkilder

Author

Tsitonaki, Katerina, Roost, Sandra, Larsen, Lars, Johansen, Anders, Gosewinkel, Ulrich Bay, and Nielsen, Tue Kjærgaard

Subjects
pesticider, oprensning
Abstract

Denne rapport omhandler et pilotforsøg i felten, hvor det er undersøgt, hvorvidt aerob nedbrydning af phenoxysyre-pesticider kan stimuleres ved tilsætning af ilt suppleret med tilsætning af specifikke pesticidnedbrydende bakterier. Forsøget er udført på en forurenet lokalitet, Skelstofte, hvor der er konstateret en forurening med phenoxysyrer-pesticider, som er vurderet til at kunne udgøre en grundvandsrisiko

Published
2017

19. Section 3 - Phytoscreening with tree cores

Author

Trapp, S., Algreen, M., Rein, A., Gosewinkel, Ulrich Bay, Holm, O., Kästner, Matthias, Braeckevelt, Mareike, Döberl, Gernot, Cassiani, Giorgio, Petrangeli Papini, Marco, Leven-Pfister, Carsten, and van Ree, Derek

Published
2012

20. Tree core monitoring

Author

Trapp, Stefan, Algren, Mette, Rein, Arno, Gosewinkel, Ulrich Bay, Holm, Olaf, Kästner, Matthias, Braeckevelt, Mareike, Döberl, Gernot, Cassiani, Giorgio, Petrangeli Papini, Marco, Leven-Pfister, Carsten, and van Ree, Derk

Published
2012

24. Application of passive dosing to study the biotransformation and biodegradation of hydrophobic

Author

Smith, Kilian E. C., Rein, Arno, Heringa, MB, Mayer, Philipp, Gosewinkel, Ulrich Bay, Smith, Kilian E. C., Rein, Arno, Heringa, MB, Mayer, Philipp, and Gosewinkel, Ulrich Bay

Abstract

Achieving well-defined and constant dissolved concentrations of hydrophobic compounds is challenging due to volatilization or sorptive losses. With passive dosing, continual partitioning into the test medium of compound(s) loaded in a polymer compensates for losses, and provides defined and constant dissolved concentrations. Passive dosing can be used for studying biotransformation/ degradation. Here, the polymer HOC reservoir also compensates for losses due to the bio-transformation/degradation process itself. Furthermore, a large mass of test compound is introduced so that compound turnover is significant even at low dissolved concentrations thus facilitating measurement of the relevant endpoint (e.g., metabolic products in biotransformation or growth in biodegradation). This study details two applications of passive dosing for studying bio-transformation/degradation. A format has been developed to study the biodegradation of phenanthrene and fluoranthene by the bacterial strain EPA 505, allowing degradation rates to be quantified at defined freely dissolved concentrations from mg/L down to ng/L levels. Passive dosing was also applied for quantifying the mutagenicity of benzo(a)pyrene metabolites produced after activation by the liver S9 mix in the in vitro Ames II assay. Compared to the case with spiking, responses from passive dosing were shifted by a factor 100-1000 to lower concentrations, and were also more reproducible between repeated tests. This difference in apparent sensitivity cannot solely be explained by partitioning, and is due to slow dissolution kinetics as well as massdepletion of the spiked benzo(a)pyrene. Therefore, passive dosing is a useful tool for the study of hydrophobic compound bio-transformation/degradation at well-defined dissolved concentrations down to very low levels. Important advantages include studying process kinetics at precisely

Published
2011

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