The bacterial strains and plasmids used in this study are listed in Table 4 . L. helveticus DSM 20075 (ATCC 15009) was obtained from the German Collection of Microorganisms and Cell Cultures (DSMZ; Braunschweig, Germany). Lactobacillus plantarum WCFS1, isolated from human saliva as described by Kleerebezem et al. [39 (link)], was originally obtained from NIZO Food Research (Ede, The Netherlands) and maintained in the culture collection of the Norwegian University of Life Sciences, Ås, Norway. Lactobacillus strains were cultivated MRS medium (Roth, Karlsruhe, Germany) at 37 °C without agitation. Escherichia coli NEB5α (New England Biolabs, Ipswich, MA, USA) and E. coli MB2159 (D-alanine auxotrophe) [40 (link)] were used as cloning hosts in the transformation of DNA fragments; whereas E. coli BL21 Star DE3 (Invitrogen, Carlsbad, CA, USA) and E. coli T7 Express (Novagen, Darmstadt, Germany) were used as the expression hosts. E. coli strains were grown in Luria-Bertani (LB) medium at 37 °C with shaking at 200 rpm. The antibiotic concentrations were 100 μg/mL ampicillin for E. coli, 10 μg/mL of chloramphenicol (Cm) for both Lactobacillus and E. coli, or 5 μg/mL and 200 μg/mL of erythromycin for Lactobacillus and E. coli, respectively. E. coli MB2159 and L. plantarum TLG02 were cultivated in the respective media supplemented with D-alanine (200 μg/mL).
Mrs medium
Manufactured by Carl Roth
Sourced in Germany
MRS medium is a culture medium formulated for the isolation and enumeration of lactobacilli. It provides the necessary nutrients and growth factors required for the cultivation of these bacteria.
Automatically generated - may contain errors
Lab products found in correlation
Peptone water, by Carl Roth (2 mentions)
M17 agar, by Thermo Fisher Scientific (2 mentions)
M17 medium, by Thermo Fisher Scientific (2 mentions)
Mrs agar, by Carl Roth (2 mentions)
Escherichia coli neb5α, by New England Biolabs (1 mentions)
E coli bl21 star de3, by Thermo Fisher Scientific (1 mentions)
3 protocols using mrs medium
1
Bacterial Strains and Cultivation Conditions
2
Preparation of Yogurt Starter Cultures
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S. thermophilus DIL 5218 and L. delbrueckii subsp. bulgaricus DSMZ 20081 T were used as yogurt starter culture and routinely cultured in M17 medium (Oxoid) and MRS medium (Carl Roth) at 37 °C and 42 °C, respectively. Cells counts were determined using M17 agar (Oxoid) and MRS agar (Carl Roth) and incubating at 37 °C and 42 °C, respectively, for 24 h. For each experiment the strains were revived from frozen glycerol stocks on agar plates. Overnight liquid cultures were prepared by inoculating a colony in the corresponding liquid medium and incubating for 20 h. Working cultures were prepared by inoculation of the liquid medium with 10% overnight liquid culture and incubation at the relevant temperature for 4 h until reaching the middle of the exponential phase. Cell suspensions were prepared by centrifugation of a working culture at 10,000×g and washing once in 0.1% peptone water (Carl Roth) before re-suspending in the same medium. The desired cell concentration of 7.5 × 10 7 CFU/mL was achieved by adding sterile 0.1% peptone water.
3
Preparation of Yogurt Starter Cultures
Check if the same lab product or an alternative is used in the 5 most similar protocols
+ Expand
S. thermophilus DIL 5218 and L. delbrueckii subsp. bulgaricus DSMZ 20081 T were used as yogurt starter culture and routinely cultured in M17 medium (Oxoid) and MRS medium (Carl Roth) at 37 °C and 42 °C, respectively. Cells counts were determined using M17 agar (Oxoid) and MRS agar (Carl Roth) and incubating at 37 °C and 42 °C, respectively, for 24 h. For each experiment the strains were revived from frozen glycerol stocks on agar plates. Overnight liquid cultures were prepared by inoculating a colony in the corresponding liquid medium and incubating for 20 h. Working cultures were prepared by inoculation of the liquid medium with 10% overnight liquid culture and incubation at the relevant temperature for 4 h until reaching the middle of the exponential phase. Cell suspensions were prepared by centrifugation of a working culture at 10,000×g and washing once in 0.1% peptone water (Carl Roth) before re-suspending in the same medium. The desired cell concentration of 7.5 × 10 7 CFU/mL was achieved by adding sterile 0.1% peptone water.
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