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Additional file 1: Figure S1. GFP production after 48 h of induction with different inducers. (A) GFP production was monitored by measuring the fluorescence intensity on the crude extracts. (B) GFP production by a single cell was determined by flow cytometry from whole cells. Mean values of three (A) or four (B) independent measurements are represented with error bars indicating standard deviations. Statistical analyses were performed using unpaired two-tailed Student's t-test, only significant changes (*p < 0.05) are reported. Figure S2. Flow cytometry analysis of GFP-producing cells. BL21 (DE3) E. coli cells overexpressing GFP were analyzed before the induction (time 0) and after 6 h, 24 h and 48 h after the induction with IPTG (A), lactose (B), and CWP (C), at 25 °C. GFP fluorescence was plotted in function of forward scatter (FSC), which is proportional to cell size. One of three independent measurements was shown. Figure S3. Effects of IPTG and CWP on ROS generation in cells producing ATX3-Q55. ROS generation was monitored using DCF-DA, a permeable probe that is oxidized in the presence of ROS forming the fluorescent compound DCF. Mean values of three independent measurements are shown with error bars indicating standard deviations. Statistical analyses were performed using unpaired two-tailed Student’s t-test, *p < 0.05, **p < 0.01, ***p < 0.001.

Séance : Alimentation; International audience; To study the interactions between the plant biodiversity of pastures, ruminants, their microbiota and their products, an in vivo and in vitro experiment was carried out in the spring 2018. After a 5-week adaptation period on a common plot, 2 groups of 7 dairy cows were led for 4 weeks on 2 plots with contrasting levels of plant biodiversity: LD (19 species, mainly grasses) and HD (56 species, mostly dicots). Samples of grass selected by the cows (simulated bites), rumen fluid, faeces, and milk were taken at the end of the experimental periods, respectively. Milk production and protein and fat concentration were similar between treatments. The grass from group HD was more fibrous and had a higher total tannin content. Grass total fatty acids (FA) and C18:3 n-3 contents were higher for LD. Total gas production during in vitro ruminal fermentation of HD grass was lower compared to LD, this being probably due to the inhibition of bacterial proliferation by tannins, which also protected the digestion of the dry matter of the HD group compared to LD. Ruminal fluid of HD cows differed from that of LD cows by a lower concentration of total FA but a higher proportion of polyunsaturated fatty acids (PUFA). This suggests a less complete biohydrogenation of dietary PUFA induced by tannins. The β-diversity, which considers the equipartition of species, showed differences between the bacterial and fungal communities of the ruminal liquid and the faeces of the cows between the 2 treatments. The FA profile of milk from LD cows is distinguished by a higher concentration of C18:2 c9t11. Moreover, the quantity of C18:3 n-3 is not significantly different between the treatments, despite the marked differences on grass. The lower total FA and n-3 content of the grass from the HD group could have been compensated by the protective role of tannins in the rumen.; Pour étudier les interactions entre la biodiversité végétale des prairies, les ruminants, leur microbiote et leurs produits, des expérimentations in vivo et in vitro ont été menées au printemps 2018. Après une période d’adaptation de 5 semaines sur une parcelle commune, 2 lots de 7 vaches laitières ont été conduits pendant 4 semaines sur 2 parcelles présentant des niveaux de biodiversité végétale contrastés : LD (diversité flaible,19 espèces, beaucoup des graminées) et HD (diversité élevée 56 espèces, beaucoup des dicotylédones). Des prélèvements d’herbe sélectionnés par les vaches (bouchées simulées), de liquide ruminal, de fèces et de lait ont été réalisés en fin de période d’adaptation, et en fin de période expérimentale. La production laitière et les taux protéique et butyreux était similaires entre les lots. L'herbe du lot HD était plus fibreuse et avait une teneur en tanins totaux plus élevée. La teneur en acides gras (AG) totaux de l’herbe, et en C18:3 n3, était plus élevée pour LD. La production totale de gaz lors de la fermentation ruminale in vitro de l’herbe HD était plus faible par rapport à LD, ceci étant probablement dû à l’inhibition de l’activité bactérienne par les tanins, qui ont également protégé la digestion de la matière sèche (MS) du lot HD par rapport au lot LD. Le liquide ruminal des vaches HD a présenté une concentration plus faible en AG totaux mais une proportion plus élevée en acides gras polyinsaturés (AGPI). Cela suggère une biohydrogénation moins complète des AGPI alimentaires induite par les tanins. La β-diversité, qui considère l’équipartition des espèces, a montré des différences entre des communautés bactériennes et fongiques du liquide ruminal et des fèces des vaches entre les 2 lots. Le profil en AG du lait des vaches LD se distingue par une concentration plus importante en C18:2 c9t11. Par contre, la quantité de C18:3 n-3 n’est pas significativement différente entre les lots, malgré les différences marquées sur l’herbe. Le contenu en AG totaux et en n-3 plus faible de l’herbe du lot HD, pourrait avoir été compensé par l’effet protecteur des tanins dans le rumen.

Additional file 1: Table S1. Growth rates of L. starkeyi in different growth conditions. Cells were grown at different % of SBP hydrolysate, with or without 6% molasses, in batch and pulsed fed-batch cultures. Growth rates has been calculated thanks to a semi-logarithmic graph (data not shown). ND: not determined; *P < 0.05; NS, no statistical significance. Figure S1. FTIR microspectroscopy analysis of L. starkeyi. The FTIR absorption spectra of L. starkeyi intact cells are reported at 0 and 144 h of growth in 3% SBP hydrolysate containing 6% of molasses. For comparison, spectra have been normalized to amide I band area. The assignment of the bands due to the biomolecules discussed in the text is reported. Figure S2. Linear relation between OD660 and lipid accumulation measured as CH stretching band area (A) and ester C=O (B) by Fourier transform infrared (FTIR) of L. starkeyi cells growing in 3% SBP hydrolysate blended with 1%, 2% or 6% of molasses in batch and pulsed-fed batch cultures. Tables show the values corresponding to the slope of the regression lines and to the coefficients of determination (R2). Figure S3. Sucrose, glucose, arabinose, acetic acid and lactic acid concentrations during growth of L. starkeyi in SBP hydrolysate generated at 3% TS fed with pulses of molasses. Figure S4. Lipase catalysed transesterification of lipids produced by L. starkeyi cultivated in SBP fed with molasses (pattern E). 500 µl of lipids were incubated with 12 mg of Novozym 435 at 37°C and 160 rpm. 2.5% of methanol were added at time 0, 24, 48 and 72 h (indicated by arrows).