Nucleotide sequence of the argF regulatory region of Escherichia coli K-12

The nucleotide sequence of the control region of the divergent argECBH operon has been established in the wild type and in mutants affecting expression of these genes. The argE and argCBH promoters face each other and overlap with an operator region containing two domains which may act as distinct repressor binding sites. A long leader sequence -not involved in attenuation -precedes argCBH. Overlapping of the argCBH promoter and the region involved in ribosome mobilization for argE translation explains the dual effect of some mutations. Mutations causing semi-constitutive expression of argE improve putative promoter sequences within argC. Implications of these results regarding control mechanisms in amino acid biosynthesis and their evolution are discussed.

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“…The argF and argI regulatory regions are also devoid of attenuation features (41,42,46). The function, if any, of the argCBH leader is unknown.…”

Section: Initiation Of Arge Transcriptionmentioning

confidence: 99%

The regulatory region of the divergentargECBHoperon inEscherichia coliK-12

et al. 1982

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“…The sequence from one end of the insert of plasmid pUST115 was found to be similar to that of the argI and argF genes of E. coli. Both genes encode the ornithine carbamoyltransferase (1,45). In S. typhimurium, however, there is only one gene for this enzyme, the argI gene (55), which is located at min 99, localizing the miaE gene to this minute.…”

Section: Resultsmentioning

confidence: 99%

Isolation of the gene (miaE) encoding the hydroxylase involved in the synthesis of 2-methylthio-cis-ribozeatin in tRNA of Salmonella typhimurium and characterization of mutants

Persson

Björk

1993

J Bacteriol

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The modified nucleoside 2-methylthio-N-6-isopentenyl adenosine (ms2i6A) is present at position 37 (3' of the anticodon) of tRNAs that read codons beginning with U except tRNASer in Escherichia coli. Salmonella typhimurium 2-methylthio-cis-ribozeatin (ms2io6A) is found in tRNA, probably in the corresponding species that have ms2i6A in E. coli. The gene (miaE) for the tRNA(ms2io6A)hydroxylase of S. typhimurium was isolated by complementation in E. coli. The miaE gene was localized close to the argI gene at min 99 of the S. typhimurium chromosomal map. Its DNA sequence and transcription pattern together with complementation studies revealed that the miaE gene is the second gene of a dicistronic operon. Southern blot analysis showed that the miaE gene is absent in E. coli, a finding consistent with the absence of the hydroxylated derivative of ms2i6A in this species. Mutants of S. typhimurium which have MudJ inserted in the miaE gene and which, consequently, are blocked in the ms2i6A hydroxylation reaction were isolated. Unexpectedly, such mutants cannot utilize the citric acid cycle intermediates malate, fumarate, and succinate as carbon sources.

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“…This result was unexpected because higher attachment rates are typically reported for fine-grained clay materials, rather than sandy soils. In general, the intrinsic lower surface area of coarser soils should result in less adsorption of microbes compared to finer textured soils [10,48,49]. In addition, the smaller pores that are prevalent in fine-grained soils are more effective for mechanical filtration (straining) of microbes than those in coarser porous soils.…”

Section: Discussionmentioning

confidence: 99%

Transport of Pathogen Surrogates in Soil Treatment Units: Numerical Modeling

Morales

Atoyan

Amador

et al. 2014

Water

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Abstract:Segmented mesocosms (n = 3) packed with sand, sandy loam or clay loam soil were used to determine the effect of soil texture and depth on transport of two septic tank effluent (STE)-borne microbial pathogen surrogates-green fluorescent protein-labeled E. coli (GFPE) and MS-2 coliphage-in soil treatment units. HYDRUS 2D/3D software was used to model the transport of these microbes from the infiltrative surface. Mesocosms were spiked with GFPE and MS-2 coliphage at 10 5 cfu/mL STE and 10 5 -10 6 pfu/mL STE, respectively. In all soils, removal rates were >99.99% at 25 cm. The transport simulation compared (1) optimization; and (2) trial-and-error modeling approaches. Only slight differences between the transport parameters were observed between these approaches. Treating both the die-off rates and attachment/detachment rates as variables resulted in an overall better model fit, particularly for the tailing phase of the experiments. Independent of the fitting procedure, attachment rates computed by the model were higher in sandy and sandy loam soils than clay, which was attributed to unsaturated flow conditions at lower water content in the coarser-textured soils. Early breakthrough of the bacteria and virus indicated the presence of preferential flow in the system in the structured clay loam soil, resulting in faster movement of water and microbes through the soil relative to a conservative tracer (bromide).

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Nucleotide sequence of the argF regulatory region of Escherichia coli K-12

Cited by 21 publications

References 62 publications

The regulatory region of the divergentargECBHoperon inEscherichia coliK-12

The regulatory region of the divergentargECBHoperon inEscherichia coliK-12

Isolation of the gene (miaE) encoding the hydroxylase involved in the synthesis of 2-methylthio-cis-ribozeatin in tRNA of Salmonella typhimurium and characterization of mutants

Transport of Pathogen Surrogates in Soil Treatment Units: Numerical Modeling

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