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Poster De Conférence Année : 2016

Transcriptomic adaptation of [i]staphylococcus xylosus[/i] to a cheese model

Résumé

Staphylococcus xylosus belongs to the food-related species of coagulase-negative staphylococci. This species is present in the natural microbiota of traditional cheeses. It is also commercially available as an adjunct culture to enhance the aroma and texture of cheeses, as well as the color of the surface of smeared cheeses. The molecular mechanisms allowing the growth and adaptation of S. xylosus in the dairy products are still poorly understood. A microarray representing the S. xylosus C2a genome was used to determine how the gene expression profile was modified during growth and adaptation to a cheese model. The C2a strain was inoculated at 5.6 log CFU/g in ultra filtered milk concentrated 5.5-fold and supplemented with UHT cream and salt. Then rennet was added. The temperature of incubation was decreased from 30°C to 12°C after 10 hours of culture, to mimic the temperature shift generally encountered during cheese making. The growth of S. xylosus in the cheese model was exponential until 5 hours and reached a maximum of 8.7 log CFU/g at 24h. S. xylosus population remained almost at this population level after 48 hours of incubation. Total RNA extractions were performed directly from the solid dairy matrix inoculated with S. xylosus after 6, 24 and 48 hours of incubation. Compared to the 6 hours time point sampling, more than 1000 genes of S. xylosus were differentially expressed at 24 and/or 48 hours of incubation. In particular, extensive upregulation of genes involved in the biosynthesis of purines, pyrimidines, aromatic amino acids and arginine was observed. This work generates a comprehensive genome-wide picture of what genes are modulated during S. xylosus growth and adaptation to a cheese model. Our study increases the understanding of the physiology of adjunct culture in the first step of cheese making process.
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Dates et versions

hal-01348377 , version 1 (22-07-2016)

Identifiants

  • HAL Id : hal-01348377 , version 1
  • PRODINRA : 361408

Citer

Sergine Even, Sabine Leroy, Pierre Micheau, Anne de La Foye, Yves Le Loir, et al.. Transcriptomic adaptation of [i]staphylococcus xylosus[/i] to a cheese model. Food Micro 2016, Jul 2016, Dublin, Ireland. 2016. ⟨hal-01348377⟩
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