Publications by authors named "A Guyonvarch"

Article Synopsis
  • Six genes associated with high molecular weight penicillin-binding proteins (Pbp) are found in the β-lactam-resistant strain K411.
  • One specific gene linked to penicillin-binding protein 2c (Pbp2c) is present in resistant strains but absent in sensitive ones, demonstrating a clear relationship with resistance levels.
  • The Pbp2c protein significantly enhances β-lactam resistance and is regulated by a specific system activated by β-lactams, requiring up to 48 hours for detection in certain strains, with Pbp2c-expressing strains showing resistance to all tested β-lactam antibiotics.
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Based on the "nutritional programming" concept, we evaluated the long-term effects of an early four-day caloric restriction (40% reduction in feed allowance compared to a normal feeding level) at the protozoea stage in whiteleg shrimp. We analyzed long-term programming of shrimp by studying metabolism at the molecular level, through RT-qPCR of key biomarkers (involved in intermediary metabolism and digestion). The mRNA levels (extracted from the whole body) were analyzed after the stimulus and after the rearing period, at 20 and 35 days, respectively.

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Early-life microbial exposure is of particular importance to growth, immune system development and long-lasting health. Hence, early microbiota composition is a promising predictive biomarker for health and disease but still remains poorly characterized in regards to susceptibility to diarrhoea. In the present study, we aimed to assess if gut bacterial community diversity and composition during the suckling period were associated with differences in susceptibility of pigs to post-weaning diarrhoea.

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Metabolic Flux Analysis is now viewed as essential to elucidate the metabolic pattern of cells and to design appropriate genetic engineering strategies to improve strain performance and production processes. Here, we investigated carbon flux distribution in two Streptomyces coelicolor A3 (2) strains: the wild type M145 and its derivative mutant M1146, in which gene clusters encoding the four main antibiotic biosynthetic pathways were deleted. Metabolic Flux Analysis and (13)C-labeling allowed us to reconstruct a flux map under steady-state conditions for both strains.

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The transfer of passive immunity from sows to piglets is important and it is the first immune protection of the new born piglet. Improving sows immunity by adding immuno-stimulating product in sows diet can positively affect colostrum composition and transfer of immune molecules to piglets. The aim of the current study is to evaluate the benefit of a different solution, made of specific fatty acids from marine origin that have been used in human medicine for decades, for sows and piglets.

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