Adaptation of Escherichia coli to high osmolarity environments: Osmoregulation of the high-affinity glycine betaine transport system ProU

Lucht, Jan M.

doi:10.1016/0168-6445(94)90008-6

Cited by 123 publications

(199 citation statements)

References 86 publications

(175 reference statements)

Supporting

Mentioning

193

Contrasting

Unclassified

Order By: Relevance

“…Surprisingly, glycine betaine was detected in the culture medium of the two strains proficient in glycine betaine synthesis (Fig. 2, lanes 3, 4, and 6), suggesting that these MKH13-derived strains, which are defective in the glycine betaine transport systems ProP and ProU (35), are incapable of retaining all of the newly synthesized glycine betaine inside the cell. This loss of the newly synthesized glycine betaine probably reflects the presence of specific export systems for this osmoprotectant (28,32).…”

Section: Vol 178 1996 Glycine Betaine Synthesis In B Subtilis 5123mentioning

confidence: 99%

“…1) grown either in low-osmolarity (SMM) or high-osmolarity (SMM plus 0.4 M NaCl) minimal medium in the presence or absence of 1 mM choline. A gbsA-specific primer was annealed to the RNA and extended with reverse transcriptase in the presence of 35 S-dATP, and the reaction products were then separated on a DNA sequencing gel and visualized by autoradiography (Fig. 7).…”

Section: Vol 178 1996 Glycine Betaine Synthesis In B Subtilis 5125mentioning

confidence: 99%

“…Since proper maintenance of turgor is essential for cell division and survival, bacteria must have active mechanisms to respond to changes in the environmental osmolarity in order to compete successfully for their ecological niche (8,35). Exposure of Bacillus subtilis to a hypersaline environment incites an integrated physiological adaptation reaction that is aimed at restoring the disturbed cellular water balance, maintaining optimal turgor, and protecting cell components from the detrimental effects of high ionic strength.…”

mentioning

confidence: 99%

“…A more effective defense against these growth conditions is the accumulation of large amounts of osmoprotectants which can be amassed to high intracellular levels without disturbing essential functions of the cell (8,35). One of the most important osmoprotectants is glycine betaine.…”

mentioning

confidence: 99%

“…In contrast, the systems mediating the enzymatic conversion of choline into glycine betaine are only marginally stimulated by an increase in medium osmolarity (4). B. subtilis shares the ability to oxidize choline to glycine betaine for osmoprotective purposes with a number of gram-negative and gram-positive bacteria (8,15,35). This process has been most intensively studied at both the molecular and biochemical levels for E. coli (30,31).…”

mentioning

confidence: 99%

See 4 more Smart Citations

Synthesis of the osmoprotectant glycine betaine in Bacillus subtilis: characterization of the gbsAB genes

et al. 1996

View full text Add to dashboard Cite

Synthesis of the osmoprotectant glycine betaine from the exogenously provided precursor choline or glycine betaine aldehyde confers considerable osmotic stress tolerance to Bacillus subtilis in high-osmolarity media. Using an Escherichia coli mutant (betBA) defective in the glycine betaine synthesis enzymes, we cloned by functional complementation the genes that are required for the synthesis of the osmoprotectant glycine betaine in B. subtilis. The DNA sequence of a 4.1-kb segment from the cloned chromosomal B. subtilis DNA was established, and two genes (gbsA and gbsB) whose products were essential for glycine betaine biosynthesis and osmoprotection were identified. The gbsA and gbsB genes are transcribed in the same direction, are separated by a short intergenic region, and are likely to form an operon. The deduced gbsA gene product exhibits strong sequence identity with members of a superfamily of specialized and nonspecialized aldehyde dehydrogenases. This superfamily comprises glycine betaine aldehyde dehydrogenases from bacteria and plants with known involvement in the cellular adaptation to high-osmolarity stress and drought. The deduced gbsB gene product shows significant similarity to the family of type III alcohol dehydrogenases. B. subtilis mutants with defects in the chromosomal gbsAB genes were constructed by marker replacement, and the growth properties of these mutant strains in high-osmolarity medium were analyzed. Deletion of the gbsAB genes destroyed the cholineglycine betaine synthesis pathway and abolished the ability of B. subtilis to deal effectively with high-osmolarity stress in choline-or glycine betaine aldehyde-containing medium. Uptake of radiolabelled choline was unaltered in the gbsAB mutant strain. The continued intracellular accumulation of choline or glycine betaine aldehyde in a strain lacking the glycine betaine-biosynthetic enzymes strongly interfered with the growth of B. subtilis, even in medium of moderate osmolarity. A single transcription initiation site for gbsAB was detected by high-resolution primer extension analysis. gbsAB transcription was initiated from a promoter with close homology to A -dependent promoters and was stimulated by the presence of choline in the growth medium.

show abstract

Section: Vol 178 1996 Glycine Betaine Synthesis In B Subtilis 5123mentioning

confidence: 99%

Section: Vol 178 1996 Glycine Betaine Synthesis In B Subtilis 5125mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 3 more Smart Citations

Synthesis of the osmoprotectant glycine betaine in Bacillus subtilis: characterization of the gbsAB genes

et al. 1996

View full text Add to dashboard Cite

show abstract

Cyclic nucleotides in archaea: Cyclic di‐AMP in the archaeonHaloferax volcaniiand its putative role

et al. 2019

View full text Add to dashboard Cite

The role of cyclic nucleotides as second messengers for intracellular signal transduction has been well described in bacteria. One recently discovered bacterial second messenger is cyclic di‐adenylate monophosphate (c‐di‐AMP), which has been demonstrated to be essential in bacteria. Compared to bacteria, significantly less is known about second messengers in archaea. This study presents the first evidence of in vivo presence of c‐di‐AMP in an archaeon. The model organism Haloferax volcanii was demonstrated to produce c‐di‐AMP. Its genome encodes one diadenylate cyclase (DacZ) which was shown to produce c‐di‐AMP in vitro. Similar to bacteria, the dacZ gene is essential and homologous overexpression of DacZ leads to cell death, suggesting the need for tight regulation of c‐di‐AMP levels. Such tight regulation often indicates the control of important regulatory processes. A central target of c‐di‐AMP signaling in bacteria is cellular osmohomeostasis. The results presented here suggest a comparable function in H. volcanii. A strain with decreased c‐di‐AMP levels exhibited an increased cell area in hypo‐salt medium, implying impaired osmoregulation. In summary, this study expands the field of research on c‐di‐AMP and its physiological function to archaea and indicates that osmoregulation is likely to be a common function of c‐di‐AMP in bacteria and archaea.

show abstract

Crystal structure of the effector‐binding domain of the trehalose‐repressor of escherichia coli, a member of the LacI family, in its complexes with inducer trehalose‐6‐phosphate and noninducer trehalose

et al. 1998

View full text Add to dashboard Cite

The crystal structure of the Escherichia coli trehalose repressor (TreR) in a complex with its inducer trehalose-6-phosphate was determined by the method of multiple isomorphous replacement (MIR) at 2.5 8, resolution, followed by the structure determination of TreR in a complex with its noninducer trehalose at 3.1 8, resolution. The model consists of residues 61 to 315 comprising the effector binding domain, which forms a dimer as in other members of the LacI family. This domain is composed of two similar subdomains each consisting of a central P-sheet sandwiched between a-helices. The effector binding pocket is at the interface of these subdomains. In spite of different physiological functions, the crystal structures of the two complexes of TreR turned out to be virtually identical to each other with the conformation being similar to those of the effector binding domains of the LacI and PurR in complex with their effector molecules. According to the crystal structure, the noninducer trehalose binds to a similar site as the trehalose portion of trehalose-6-phosphate. The binding affinity for the former is lower than for the latter. The noninducer trehalose thus binds competitively to the repressor. Unlike the phosphorylated inducer molecule, it is incapable of blocking the binding of the repressor headpiece to its operator DNA. The ratio of the concentrations of trehalose-6-phosphate and trehalose thus is used to switch between the two alternative metabolic uses of trehalose as an osmoprotectant and as a carbon source.

show abstract

Adaptation of Escherichia coli to high osmolarity environments: Osmoregulation of the high-affinity glycine betaine transport system ProU

Cited by 123 publications

References 86 publications

Synthesis of the osmoprotectant glycine betaine in Bacillus subtilis: characterization of the gbsAB genes

Synthesis of the osmoprotectant glycine betaine in Bacillus subtilis: characterization of the gbsAB genes

Cyclic nucleotides in archaea: Cyclic di‐AMP in the archaeonHaloferax volcaniiand its putative role

Crystal structure of the effector‐binding domain of the trehalose‐repressor of escherichia coli, a member of the LacI family, in its complexes with inducer trehalose‐6‐phosphate and noninducer trehalose

Contact Info

Product

Resources

About