B-L nonconservation and neutron oscillation

Chang, Lay Nam; Chang, Ngee-Pong

doi:10.1016/0370-2693(80)90314-7

Cited by 90 publications

(41 citation statements)

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“…S. typhimurium CDC 6516-60 (ATCC 14028) was obtained from J. Mekalanos. pBC10 has the 4.7-kbp EcoRI-to-PstI fragment containing the E. coli K-12 phoBR operon from pBC6 (52) cloned into pBR322 (8). pBW120 carries the entire phnC-to-phnP gene cluster from E. coli B cloned into pUC18 (51).…”

Section: Methodsmentioning

confidence: 99%

Molecular cloning, mapping, and regulation of Pho regulon genes for phosphonate breakdown by the phosphonatase pathway of Salmonella typhimurium LT2

et al. 1995

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Two pathways exist for cleavage of the carbon-phosphorus (C-P) bond of phosphonates, the C-P lyase and the phosphonatase pathways. It was previously demonstrated that Escherichia coli carries genes (named phn) only for the C-P lyase pathway and that Enterobacter aerogenes carries genes for both pathways (K.-S. Lee, W. W. Metcalf, and B. L. Wanner, J. Bacteriol. 174:2501-2510, 1992). In contrast, here it is shown that Salmonella typhimurium LT2 carries genes only for the phosphonatase pathway. Genes for the S. typhimurium phosphonatase pathway were cloned by complementation of E. coli ⌬phn mutants. Genes for these pathways were proven not to be homologous and to lie in different chromosomal regions. The S. typhimurium phn locus lies near 10 min; the E. coli phn locus lies near 93 min. The S. typhimurium phn gene cluster is about 7.2 kb in length and, on the basis of gene fusion analysis, appears to consist of two (or more) genes or operons that are divergently transcribed. Like that of the E. coli phn locus, the expression of the S. typhimurium phn locus is activated under conditions of P i limitation and is subject to Pho regulon control. This was shown both by complementation of the appropriate E. coli mutants and by the construction of S. typhimurium mutants with lesions in the phoB and pst loci, which are required for activation and inhibition of Pho regulon gene expression, respectively. Complementation studies indicate that the S. typhimurium phn locus probably includes genes both for phosphonate transport and for catalysis of C-P bond cleavage.Phosphonates (Pn) are a large class of molecules containing a direct carbon-phosphorus (C-P) bond in place of the more familiar carbon-oxygen-phosphorus bond of phosphoesters. Although Pn do not exist in all organisms, they do exist in many different ones. Pn have been found in organisms as diverse as the intracellular procaryote Bdellovibrio species, the filamentous bacteria streptomycetes, the protozoans Tetrahymena and Trypanosoma spp., mollusks, insects, and others. In these organisms, Pn have been isolated as constituents of glycolipids, glycoproteins, polysaccharides, or phosphonolipids. In Bacteroides fragilis, Pn were identified as components of capsular polysaccharide (6); in streptomycetes, Pn are synthesized as antibiotics such as fosfomycin (25); in Tetrahymena spp., Pn exist as phosphonolipids (19); in Trypanosoma cruzi, Pn are components of lipopeptidophosphoglycan (the major cell surface glycoconjugate [10]); in a sea anemone, Pn are the major P compounds (38); and in a locus, a Pn is the principal P compound of hemolymph (20). Yet, in spite of their widespread natural occurrence, the biological role of natural Pn is poorly understood (17). In phosphonolipids, 2-aminoethylphosphonate (AEPn) exists in place of its analog ethanolamine phosphate.No doubt because of the abundance of PN in nature, bacteria have acquired pathways for Pn breakdown. Bacteria capable of breaking the C-P bond may use Pn as a sole P source, for which two pathways exist, the C-P l...

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Section: Methodsmentioning

confidence: 99%

Molecular cloning, mapping, and regulation of Pho regulon genes for phosphonate breakdown by the phosphonatase pathway of Salmonella typhimurium LT2

et al. 1995

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“…These were made by the rep technique for allele replacement in which an M13 recombinant phage carrying a mutation is used to recombine the allele onto the chromosome by using an E. coli rep host, which is unable to replicate M13 (8,17,20; also this study). Our were from H. E. Umbarger, and S1O (ilv::Tn5) was from J. Beckwith.…”

mentioning

confidence: 99%

Use of the rep technique for allele replacement to construct mutants with deletions of the pstSCAB-phoU operon: evidence of a new role for the PhoU protein in the phosphate regulon

1993

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The phosphate regulon is negatively regulated by the PstSCAB transporter and PhoU protein by a mechanism that may involve protein-protein interaction(s) between them and the P1 sensor protein, PhoR. In order to study such presumed interaction(s), mutants with defined deletions of the pstSCAB-phoU operon were made. This was done by construction of M13 recombinant phage carrying these mutations and by recombination of them onto the chromosome by using a rep host (which cannot replicate M13) for allele replacement. These mutants were used to show that 4(pstSCAB-phoU) and A(pstB-phoU) mutations abolished Pi uptake by the PstSCAB transporter, as expected, and that AphoU mutations had no effect on uptake.Unexpectedly, AphoU mutations had a severe growth defect, and this growth defect was (largely) alleviated by a compensatory mutation in the pstSCAB genes or in the phoBR operon, whose gene products positively regulate expression of the pstSCAB-phoU operon. Because AphoU mutants that synthesize a functional PstSCAB transporter constitutively grew extremely poorly, the PhoU protein must have a new role, in addition to its role as a negative regulator. A role for the PhoU protein in intracellular P1 metabolism is proposed. Further, our results contradict those of M. Muda, N. N. Rao, and A. Torriani (J. Bacteriol. 174:8057-8064, 1992), who reported that the PhoU protein was required for P1 uptake.

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“…We isolated numerous mutants with TnphoA or TnphoA' insertions in the chromosome or high-copy plasmids (8,22,26,49 TnphoA'-9 and TnphoA'-10 can result from recombinational switching. TnphoA'-9 is a recombinant of TnphoA'-2 with TnS-112; TnphoA'-10 is a recombinant of TnphoA'-S with TnphoAASacII.…”

Section: -Bromo-mentioning

confidence: 99%

“…We used these phages to select mutants or recombinants as Kanr, Tcr, or Cmr transductants in E. coli. We used suicide plasmids in similar ways with xr E. coli and with non-E. coli strains (8,22,49). Together with other vehicles for mutagenesis with TnphoA, or Tn5, derivatives (29,36) (Table 5).…”

Section: -Bromo-mentioning

confidence: 99%

“…First, the wild-type phoA gene is our most useful reporter gene of the PHO regulon. Second, because the Pi sensor, PhoR, is thought to be a membrane protein, we had expected, but had not found, several Bap+ mutants with in-frame phoR:: TnphoA insertions (8). Therefore, we had to sequence a large collection of randomphoR::TnphoA mutations in order to identify ones that were in frame.…”

mentioning

confidence: 99%

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TnphoA and TnphoA' elements for making and switching fusions for study of transcription, translation, and cell surface localization

Wilmes-Riesenberg

Wanner

1992

J Bacteriol

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We describe a set of elements based on the transposon TnphoA for making transcriptional fusions to the lacZ gene and for making translational fusions to the phoA or lacZ structural gene. Each element can be switched, one for another, by homologous recombination, thereby allowing testing for transcription, translation, or cell surface localization determinants at the same site within a gene. We describe three kinds of elements for making each fusion type. Two Individual TnphoA, TnphoA'-lacZ (op), and TnphoA'-lacZ (pr) elements are available as transposition-proficient (Tnp+) elements encoding kanamycin or tetracycline resistance and as transposition-defective (Tnp-) elements encoding kanamycin resistance. Also, one TnphoA' element is available as a Tnp-element lacking a reporter gene and encoding chloramphenicol resistance, which was constructed as a tool to aid in switching fusions. Importantly, a fusion made with a Tnp+ TnphoA or TnphoA' element can be switched to a different fusion type simply by selecting transductants with a different drug resistance.We describe the characteristics and use of TnphoA and TnphoA' elements in this paper. Detailed descriptions of the constructions of these elements and information on their molecular structures are in the Appendix. MATERIALS AND METHODSMedia and chemicals. Media and chemicals were usually the same as described previously (38,44). Antibiotics were added to tryptone-yeast extract (TYE) or glucose M63 agar at 15 ,ug/ml for tetracycline, 50 p,g/ml for kanamycin, 12.5 or 25 ±g/ml for chloramphenicol, and 35 p,g/ml (each) for spectinomycin and streptomycin, except as noted in the text. 5-Bromo-4-chloro-3-indolyl-phosphate-p-toluidine (X-P) and

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B-L nonconservation and neutron oscillation

Cited by 90 publications

References 3 publications

Molecular cloning, mapping, and regulation of Pho regulon genes for phosphonate breakdown by the phosphonatase pathway of Salmonella typhimurium LT2

Molecular cloning, mapping, and regulation of Pho regulon genes for phosphonate breakdown by the phosphonatase pathway of Salmonella typhimurium LT2

Use of the rep technique for allele replacement to construct mutants with deletions of the pstSCAB-phoU operon: evidence of a new role for the PhoU protein in the phosphate regulon

TnphoA and TnphoA' elements for making and switching fusions for study of transcription, translation, and cell surface localization

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