caa a22 4500 475745531 CHVBK 20180406123512.0 cr unu---uuuuu 170329e20000101xx s 000 0 eng 10.1007/s002849910014 doi (NATIONALLICENCE)springer-10.1007/s002849910014 Antón Dora N. Departamento de Radiobiología, Comisión Nacional de Energía Atómica, Avda. General Paz 1499, 1650 San Martín, Argentina, AR aut Induction of the Cysteine Regulon of Salmonella typhimurium in LB Medium Affects the Response of cysB Mutants to Mecillinam [Elektronische Daten] [Dora N. Antón] Abstract.: Rapid growth of Salmonella typhimurium LT2 in rich LB-broth caused the induction of the cysteine regulon when the culture reached an optical density at 650 nm of 1.5. Addition of 0.05 mM L-cystine to LB-broth abolished induction, while 0.025 mM L-cystine delayed it for a doubling time (30 min). Induction did not occur when lack of oxygen or a temperature shift to 19°C slowed down growth in LB-broth. Uninduced cultures reached growth yield similar to that of induced cultures after overnight incubation. Growth on solid LB-medium also brought about induction, but to a lower level than in liquid medium. Leaky cysB mutants, which are sensitive to the β-lactam antibiotic mecillinam, displayed partial induction, whereas mecillinam-resistant cysB and cysE mutants showed no induction. It is suggested that induction develops in these mutants when constitutive transport systems fail to satisfy the high uptake of cysteine demanded by fast-growing cultures. The behavior of cysB mutants agrees with the hypothesis that, under some conditions, mecillinam action would be dependent on expression of the cysteine regulon. Springer-Verlag New York Inc., 2000 https://doi.org/10.1007/s002849910014 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s002849910014 text/html Onlinezugriff via DOI NATIONALLICENCE 100 1- Antón Dora N. Departamento de Radiobiología, Comisión Nacional de Energía Atómica, Avda. General Paz 1499, 1650 San Martín, Argentina, AR aut Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer