glutamicum has been found here. Biotin limitation reduces/alters synthesis of fatty and mycolic acids [16] as a consequence of reduced levels of biotinylated AccBC, the α-subunit of the acyl-carboxylases. Moreover, MGCD0103 purchase under biotin limitation conditions anaplerosis

is not fulfilled by biotin-containing pyruvate carboxylase [41, 43], but by PEP carboxylase [44]. In line with the observation that L-glutamate production by C. glutamicum wild type is known to be suppressed by an excess of biotin [45], enhancing biotin uptake by overexpression of bioYMN decreased L-glutamate production (Figure 3). Thus, BioYMN plays a role in biotin-triggered L-glutamate production by C. glutamicum. Conclusions C. glutamicum showed biotin-dependent regulation of mRNA levels of bioA, bioB, bioY, bioM, and bioN. The genes bioY, bioM, and bioN are transcribed as an operon, bioYMN. Transport assays with radio-labeled biotin revealed that BioYMN functions as a biotin uptake P005091 in vivo system with an affinity for its

substrate in the nanomolar range. Overepression of bioYMN alleviated biotin limitation and interfered with triggering L-glutamate production by biotin limitation. Methods Bacterial strains, plasmids, oligonucleotides, and culture conditions Bacterial strains and plasmids used are listed in Table 2. Escherichia coli was grown in lysogeny broth complex medium (LB) as the standard medium [46], while brain heart infusion medium (BHI, Becton Dickinson, Heidelberg, Germany) was used as complex medium for C. glutamicum. For growth experiments, in the first preculture, Amylase 50 ml BHI medium was inoculated from a fresh BHI agar plate and incubated at 30°C and 120 rpm in baffled flasks. After washing the cells in 0.9% (w/v) NaCl, the second preculture

and the main culture were inoculated to an optical density at 600 nm (OD600) of 0.5-1.0 in 50 ml CGXII minimal medium [47], which contained 0.03 g/l protocatechuic acid. As carbon and energy sources, 100-250 mM glucose or 200 mM sodium L-lactate were used. Precultures and main cultures were incubated at 30°C and 120 rpm on a rotary shaker in 500 ml-baffled shake flasks. When appropriate, C. glutamicum was cultivated with kanamycin (25 μg/ml) or spectinomycin (100 μg/ml). Growth of C. glutamicum was followed by measuring the OD600. For all cloning purposes, Escherichia coli DH5α was used as host. Table 2 Bacteria and plasmids used in this study Strain, plasmid or oligonucleotide Relevant characteristics or sequence Source, reference, or purpose E. coli strains     DH5α   Culture collection C.