Transcriptional analysis of beta-lactamase regulation in Bacillus licheniformis

Salerno, Alessandro G.; Lampen, J. O.

doi:10.1128/jb.166.3.769-778.1986

Cited by 21 publications

(10 citation statements)

References 39 publications

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“…Bernstein et al (11) reported that T ) 42°C was optimum for -lactamase production, whereas Davies and Abraham (12) reported T ) 30°C. In a more recent study, it was shown that 2-fold more -lactamase was synthesized in cultures grown at 37°C than in cultures grown at 30°C (13). Specific -lactamase activity of cells was shown to be constant irrespective of pH over the range of pH 5.5-7.5.…”

Section: Introductionmentioning

confidence: 97%

Bioprocess Parameters and Oxygen Transfer Characteristics in β‐Lactamase Production by Bacillus Species

Çelik

Çalı́k

2004

Biotechnology Progress

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After screening potential beta-lactamase producers in a medium containing penicillin G, an inducible (Bacillus subtilis NRS 1125) and a constitutive (Bacillus licheniformis 749/C ATCC 25972) beta-lactamase producer were selected. As the highest enzyme activity was obtained with B. licheniformis 749/C, the effects of the concentration of carbon sources, i.e., glucose, fructose, sucrose, citric acid, and glycerol, and nitrogen sources, i.e., (NH(4))(2)HPO(4), NH(4)Cl, yeast extract, casamino acids and peptone, pH, and temperature on beta-lactamase production were investigated with B. licheniformis 749/C in laboratory scale bioreactors. Among the investigated media, the highest volumetric activity was obtained as 270 U cm(-)(3) in the medium containing 10.0 kg m(-)(3) glucose, 1.18 kg m(-)(3) (NH(4))(2)HPO(4), 8.0 kg m(-)(3) yeast extract, and the salt solution at 32 degrees C and pH(0) = 6.0. By using the designed medium, fermentation and oxygen transfer characteristics of the bioprocess were investigated at V = 3.0 dm(3) bioreactor systems with a V(R) = 1.65 dm(3) working volume at Q(O)/V(R) = 0.5 vvm and N = 500 min(-1). At the beginning of the process the Damköhler number was <1, indicating that the process was at biochemical reaction limited condition; at t = 2-5 h both mass-transfer and biochemical reaction resistances were effective; and at t = 6-10 h (Da >>1) the bioprocess was at mass transfer limited condition. Overall oxygen transfer coefficients (K(L)a) varied between 0.01 and 0.03 s(-)(1), enhancement factor (K(L)a/K(L)a(O)) varied between 1.2 and 2.3, and volumetric oxygen uptake rate varied between 0.001 and 0.003 mol m(-)(3) s(-)(1) throughout the bioprocess. The specific oxygen uptake and the specific substrate consumption rates were the highest at t = 2 h and then decreased with the cultivation. The maximum yield of cells on substrate and the maximum yield of cells on oxygen values were obtained, respectively, as Y(X/S) = 0.34 and Y(X/O) = 1.40, at t = 5 h, whereas the highest yield of substrate on oxygen was obtained as Y(S/O) = 6.94 at t = 3.5 h. The rate of oxygen consumption for maintenance and the rate of substrate consumption for maintenance values were found, respectively, as m(O) = 0.13 kg kg(-)(1) h(-)(1) and m(S) = 3.02 kg kg(-)(1) h(-)(1).

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Section: Introductionmentioning

confidence: 97%

Bioprocess Parameters and Oxygen Transfer Characteristics in β‐Lactamase Production by Bacillus Species

Çelik

Çalı́k

2004

Biotechnology Progress

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“…The rate remains severalfold higher than that of the uninduced culture for 2 or 3 h longer (11). This prolonged induction is not the result of unusual mRNA stability, because the half-life of the ,-lactamase mRNA is only 2 to 3 min (32). Sherratt and Collins reported three possible regulatory loci for the synthesis of 1-lactamase (35).…”

Section: I8-lactamase In B Licheniformis 749mentioning

confidence: 99%

A second regulatory gene, blaR1, encoding a potential penicillin-binding protein required for induction of beta-lactamase in Bacillus licheniformis

Kobayashi¹,

Zhu²,

Nicholls³

et al. 1987

J Bacteriol

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A second regulatory locus (blaRi) required for the induction of I-lactamase synthesis in Bacillus licheniformis 749 was cloned and sequenced. The gene was located on a 5.2-kilobase-pair SphI DNA fragment which also contained the j8-lactamase (blaP) and repressor (blal) genes. Bacillus subtilis BD224 carrying these three genes synthesized P-lactamase on exposure to cephalosporin C, whereas Escherichia coli HB101 carrying the genes did not show any detectable induction of the enzyme. An open reading frame of 1,803 bases was identified as the blaRI gene by subcloning and DNA sequencing. The gene started 2 bases downstream of the termination codon of blal and was preceded by a putative Shine-Dalgarno sequence (AAGGA) with a spacing of 5 bases. The deduced blaRi product (601 amino acids) had a molecular weight of 68,425. Five transmembrane regions were predicted from the hydrophobicity profile. The region around Phe-Ala-Pro-AlaSer-Thr-Tyr-Lys (amino acids 398 to 405), which appeared to be located outside the membrane, was homologous to the binding regions of penicillin-binding proteins, including the ,-lactamases. The segment of 22 amino acids from 400 to 421 showed more than 70% homology to the penicillin-binding region of PBP 2 of E. coli. The blaR1 gene encodes a potential penicillin receptor which is required for the induction of I8-lactamase in B. licheniformis 749.The ,-lactamase of Bacillus licheniformis is a secreted protein whose synthesis is induced by ,-lactam antibiotics. On induction, the enzyme is synthesized very slowly. The rate of synthesis reaches a maximum after 1 to 1.5 h of induction and then decreases slowly over the next hour. The rate remains severalfold higher than that of the uninduced culture for 2 or 3 h longer (11). This prolonged induction is not the result of unusual mRNA stability, because the half-life of the ,-lactamase mRNA is only 2 to 3 min (32). Sherratt and Collins reported three possible regulatory loci for the synthesis of 1-lactamase (35). The blaI gene, which is 90% linked to the 3-lactamase gene (blaP), encodes the repressor to blaP. The blaRi locus is 50% linked to blaP, and mutations (R14 or R27) thought to lie in this region cause low induction of the enzyme. Mutation blaR31 in the unlinked blaR2 locus results in a low basal level of the enzyme and a defect in induction. Penicillins irreversibly bind to the cell surface of B. licheniformis (13). Consequently, there must be a system of signal transduction through the membrane, and the stimulus may reach the repressor protein through a novel process. The blaRi and blaR2 loci are possibly involved in this transduction of the stimulus.The blaP gene has been cloned and sequenced (5,18,22,24,30 expected from the DNA sequence (M. J. Grossman and J. 0. Lampen, unpublished results). The mechanism of induction is still obscure, because Escherichia coli and Bacillus subtilis carrying the 4.2-kbp EcoRI DNA fragment do not show detectable induction of the ,B-lactamase (22). The absence of the blaRl and blaR2 genes may be responsible ...

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“…This enzyme is a specific hydrolase of β-lactam antibiotics, induced in response to the presence of this class of antibiotic outside the cell (1). BLBlaI is homologous to Staphylococcus aureus BlaI (SABlaI, 126 amino acids) and MecI (SAMecI, 123 amino acids) regulators involved in the induction of BlaZ β-lactamase and resistant penicillin-binding protein 2a (SAPBP2a or SAMecA), respectively (2).…”

Section: Introductionmentioning

confidence: 99%

Conformational and thermodynamic changes of the repressor/DNA operator complex upon monomerization shed new light on regulation mechanisms of bacterial resistance against β-lactam antibiotics

Boudet

Duval

Melckebeke

et al. 2007

Nucleic Acids Research

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In absence of β-lactam antibiotics, BlaI and MecI homodimeric repressors negatively control the expression of genes involved in β-lactam resistance in Bacillus licheniformis and in Staphylococcus aureus. Subsequently to β-lactam presence, BlaI/MecI is inactivated by a single-point proteolysis that separates its N-terminal DNA-binding domain to its C-terminal domain responsible for its dimerization. Concomitantly to this proteolysis, the truncated repressor acquires a low affinity for its DNA target that explains the expression of the structural gene for resistance. To understand the loss of the high DNA affinity of the truncated repressor, we have determined the different dissociation constants of the system and solved the solution structure of the B. licheniformis monomeric repressor complexed to the semi-operating sequence OP1 of blaP (1/2OP1blaP) by using a de novo docking approach based on inter-molecular nuclear Overhauser effects and chemical-shift differences measured on each macromolecular partner. Although the N-terminal domain of the repressor is not subject to internal structural rearrangements upon DNA binding, the molecules adopt a tertiary conformation different from the crystallographic operator–repressor dimer complex, leading to a 30° rotation of the monomer with respect to a central axis extended across the DNA.These results open new insights for the repression and induction mechanisms of bacterial resistance to β-lactams.

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Transcriptional analysis of beta-lactamase regulation in Bacillus licheniformis

Cited by 21 publications

References 39 publications

Bioprocess Parameters and Oxygen Transfer Characteristics in β‐Lactamase Production by Bacillus Species

Bioprocess Parameters and Oxygen Transfer Characteristics in β‐Lactamase Production by Bacillus Species

A second regulatory gene, blaR1, encoding a potential penicillin-binding protein required for induction of beta-lactamase in Bacillus licheniformis

Conformational and thermodynamic changes of the repressor/DNA operator complex upon monomerization shed new light on regulation mechanisms of bacterial resistance against β-lactam antibiotics

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