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Patil RS, Sharma S, Bhaskarwar AV, Nambiar S, Bhat NA, Koppolu MK, Bhukya H. TetR and OmpR family regulators in natural product biosynthesis and resistance. Proteins 2023. [PMID: 37874037 DOI: 10.1002/prot.26621] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2023] [Revised: 08/30/2023] [Accepted: 10/06/2023] [Indexed: 10/25/2023]
Abstract
This article provides a comprehensive review and sequence-structure analysis of transcription regulator (TR) families, TetR and OmpR/PhoB, involved in specialized secondary metabolite (SSM) biosynthesis and resistance. Transcription regulation is a fundamental process, playing a crucial role in orchestrating gene expression to confer a survival advantage in response to frequent environmental stress conditions. This process, coupled with signal sensing, enables bacteria to respond to a diverse range of intra and extracellular signals. Thus, major bacterial signaling systems use a receptor domain to sense chemical stimuli along with an output domain responsible for transcription regulation through DNA-binding. Sensory and output domains on a single polypeptide chain (one component system, OCS) allow response to stimuli by allostery, that is, DNA-binding affinity modulation upon signal presence/absence. On the other hand, two component systems (TCSs) allow cross-talk between the sensory and output domains as they are disjoint and transmit information by phosphorelay to mount a response. In both cases, however, TRs play a central role. Biosynthesis of SSMs, which includes antibiotics, is heavily regulated by TRs as it diverts the cell's resources towards the production of these expendable compounds, which also have clinical applications. These TRs have evolved to relay information across specific signals and target genes, thus providing a rich source of unique mechanisms to explore towards addressing the rapid escalation in antimicrobial resistance (AMR). Here, we focus on the TetR and OmpR family TRs, which belong to OCS and TCS, respectively. These TR families are well-known examples of regulators in secondary metabolism and are ubiquitous across different bacteria, as they also participate in a myriad of cellular processes apart from SSM biosynthesis and resistance. As a result, these families exhibit higher sequence divergence, which is also evident from our bioinformatic analysis of 158 389 and 77 437 sequences from TetR and OmpR family TRs, respectively. The analysis of both sequence and structure allowed us to identify novel motifs in addition to the known motifs responsible for TR function and its structural integrity. Understanding the diverse mechanisms employed by these TRs is essential for unraveling the biosynthesis of SSMs. This can also help exploit their regulatory role in biosynthesis for significant pharmaceutical, agricultural, and industrial applications.
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Affiliation(s)
- Rachit S Patil
- Department of Biology, Indian Institute of Science Education and Research, Tirupati, India
| | - Siddhant Sharma
- Department of Biology, Indian Institute of Science Education and Research, Tirupati, India
| | - Aditya V Bhaskarwar
- Department of Biology, Indian Institute of Science Education and Research, Tirupati, India
| | - Souparnika Nambiar
- Department of Biology, Indian Institute of Science Education and Research, Tirupati, India
| | - Niharika A Bhat
- Department of Biology, Indian Institute of Science Education and Research, Tirupati, India
| | - Mani Kanta Koppolu
- Department of Biology, Indian Institute of Science Education and Research, Tirupati, India
| | - Hussain Bhukya
- Department of Biology, Indian Institute of Science Education and Research, Tirupati, India
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Pellegrino GM, Browne TS, Sharath K, Bari KA, Vancuren S, Allen-Vercoe E, Gloor GB, Edgell DR. Metabolically-targeted dCas9 expression in bacteria. Nucleic Acids Res 2023; 51:982-996. [PMID: 36629257 PMCID: PMC9881133 DOI: 10.1093/nar/gkac1248] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Revised: 12/11/2022] [Accepted: 12/14/2022] [Indexed: 01/12/2023] Open
Abstract
The ability to restrict gene expression to a relevant bacterial species in a complex microbiome is an unsolved problem. In the context of the human microbiome, one desirable target metabolic activity are glucuronide-utilization enzymes (GUS) that are implicated in the toxic re-activation of glucuronidated compounds in the human gastrointestinal (GI) tract, including the chemotherapeutic drug irinotecan. Here, we take advantage of the variable distribution of GUS enzymes in bacteria as a means to distinguish between bacteria with GUS activity, and re-purpose the glucuronide-responsive GusR transcription factor as a biosensor to regulate dCas9 expression in response to glucuronide inducers. We fused the Escherichia coli gusA regulatory region to the dCas9 gene to create pGreg-dCas9, and showed that dCas9 expression is induced by glucuronides, but not other carbon sources. When conjugated from E. coli to Gammaproteobacteria derived from human stool, dCas9 expression from pGreg-dCas9 was restricted to GUS-positive bacteria. dCas9-sgRNAs targeted to gusA specifically down-regulated gus operon transcription in Gammaproteobacteria, with a resulting ∼100-fold decrease in GusA activity. Our data outline a general strategy to re-purpose bacterial transcription factors responsive to exogenous metabolites for precise ligand-dependent expression of genetic tools such as dCas9 in diverse bacterial species.
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Affiliation(s)
- Gregory M Pellegrino
- Schulich School of Medicine and Dentistry, Department of Biochemistry, London, Ontario N6A 5C1, Canada
| | - Tyler S Browne
- Schulich School of Medicine and Dentistry, Department of Biochemistry, London, Ontario N6A 5C1, Canada
| | - Keerthana Sharath
- Schulich School of Medicine and Dentistry, Department of Biochemistry, London, Ontario N6A 5C1, Canada
| | - Khaleda A Bari
- Schulich School of Medicine and Dentistry, Department of Biochemistry, London, Ontario N6A 5C1, Canada
| | - Sarah J Vancuren
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Emma Allen-Vercoe
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Gregory B Gloor
- Schulich School of Medicine and Dentistry, Department of Biochemistry, London, Ontario N6A 5C1, Canada
| | - David R Edgell
- To whom correspondence should be addressed. Tel: +1 519 661 3133; Fax: +1 519 661 3175;
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Jardou M, Brossier C, Guiyedi K, Faucher Q, Lawson R. Pharmacological hypothesis: A recombinant probiotic for taming bacterial β-glucuronidase in drug-induced enteropathy. Pharmacol Res Perspect 2022; 10:e00998. [PMID: 36082825 PMCID: PMC9460963 DOI: 10.1002/prp2.998] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Revised: 07/12/2022] [Accepted: 07/26/2022] [Indexed: 11/07/2022] Open
Abstract
Advances in pharmacomicrobiomics have shed light on the pathophysiology of drug‐induced enteropathy associated with the therapeutic use of certain non‐steroidal anti‐inflammatory drugs, anticancer chemotherapies and immunosuppressants. The toxicity pathway results from the post‐glucuronidation release and digestive accumulation of an aglycone generated in the context of intestinal dysbiosis characterized by the expansion of β‐glucuronidase‐expressing bacteria. The active aglycone could trigger direct or indirect inflammatory signaling on the gut epithelium. Therefore, taming bacterial β‐glucuronidase (GUS) activity is a druggable target for preventing drug‐induced enteropathy. In face of the limitations of antibiotic strategies that can worsen intestinal dysbiosis and impair immune functions, we hereby propose the use of a recombinant probiotic capable of mimicking repressive conditions of GUS through an inducible plasmid vector.
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Affiliation(s)
- Manon Jardou
- INSERM, Univ. Limoges, Pharmacology & Transplantation, U1248, Limoges, France
| | - Clarisse Brossier
- INSERM, Univ. Limoges, Pharmacology & Transplantation, U1248, Limoges, France
| | - Kenza Guiyedi
- INSERM, Univ. Limoges, Pharmacology & Transplantation, U1248, Limoges, France
| | - Quentin Faucher
- INSERM, Univ. Limoges, Pharmacology & Transplantation, U1248, Limoges, France
| | - Roland Lawson
- INSERM, Univ. Limoges, Pharmacology & Transplantation, U1248, Limoges, France
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Muniesa M, Ballesté E, Imamovic L, Pascual-Benito M, Toribio-Avedillo D, Lucena F, Blanch AR, Jofre J. Bluephage: A rapid method for the detection of somatic coliphages used as indicators of fecal pollution in water. WATER RESEARCH 2018; 128:10-19. [PMID: 29078067 DOI: 10.1016/j.watres.2017.10.030] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Revised: 10/09/2017] [Accepted: 10/14/2017] [Indexed: 05/04/2023]
Abstract
The use of somatic coliphages as indicators of fecal and viral pollution in water and food has great potential due to the reliability, reproducibility, speed and cost effectiveness of methods for their detection. Indeed, several countries already use this approach in their water management policies. Although standardized protocols for somatic coliphage detection are available, user-friendly commercial kits would facilitate their routine implementation in laboratories. The new method presented here allows detection of up to 1 somatic coliphage in under 3.5 h, well within one working day. The method is based on a modified Escherichia coli strain with knocked-out uidB and uidC genes, which encode the transport of glucuronic acid inside cells, and overexpressing uidA, which encodes the enzyme β-glucuronidase. The enzyme accumulated in the bacterial cells only has contact with its substrate after cell lysis, such as that caused by phages, since the strain cannot internalize the substrate. When the enzyme is released into the medium, which contains a chromogen analogous to glucuronic acid, it produces a change of color from yellow to dark blue. This microbiological method for the determination of fecal pollution via the detection of culturable microorganisms can be applied to diverse sample types and volumes for qualitative (presence/absence) and quantitative analysis and is the fastest reported to date.
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Affiliation(s)
- M Muniesa
- Department of Genetics, Microbiology and Statistics, Microbiology Section, Faculty of Biology, University of Barcelona, Diagonal 643, E-08028, Barcelona, Spain.
| | - E Ballesté
- Department of Genetics, Microbiology and Statistics, Microbiology Section, Faculty of Biology, University of Barcelona, Diagonal 643, E-08028, Barcelona, Spain
| | - L Imamovic
- Department of Genetics, Microbiology and Statistics, Microbiology Section, Faculty of Biology, University of Barcelona, Diagonal 643, E-08028, Barcelona, Spain
| | - M Pascual-Benito
- Department of Genetics, Microbiology and Statistics, Microbiology Section, Faculty of Biology, University of Barcelona, Diagonal 643, E-08028, Barcelona, Spain
| | - D Toribio-Avedillo
- Department of Genetics, Microbiology and Statistics, Microbiology Section, Faculty of Biology, University of Barcelona, Diagonal 643, E-08028, Barcelona, Spain
| | - F Lucena
- Department of Genetics, Microbiology and Statistics, Microbiology Section, Faculty of Biology, University of Barcelona, Diagonal 643, E-08028, Barcelona, Spain
| | - A R Blanch
- Department of Genetics, Microbiology and Statistics, Microbiology Section, Faculty of Biology, University of Barcelona, Diagonal 643, E-08028, Barcelona, Spain
| | - J Jofre
- Department of Genetics, Microbiology and Statistics, Microbiology Section, Faculty of Biology, University of Barcelona, Diagonal 643, E-08028, Barcelona, Spain
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Abstract
Following elucidation of the regulation of the lactose operon in Escherichia coli, studies on the metabolism of many sugars were initiated in the early 1960s. The catabolic pathways of D-gluconate and of the two hexuronates, D-glucuronate and D-galacturonate, were investigated. The post genomic era has renewed interest in the study of these sugar acids and allowed the complete characterization of the D-gluconate pathway and the discovery of the catabolic pathways for L-idonate, D-glucarate, galactarate, and ketogluconates. Among the various sugar acids that are utilized as sole carbon and energy sources to support growth of E. coli, galacturonate, glucuronate, and gluconate were shown to play an important role in the colonization of the mammalian large intestine. In the case of sugar acid degradation, the regulators often mediate negative control and are inactivated by interaction with a specific inducer, which is either the substrate or an intermediate of the catabolism. These regulators coordinate the synthesis of all the proteins involved in the same pathway and, in some cases, exert crosspathway control between related catabolic pathways. This is particularly well illustrated in the case of hexuronide and hexuronate catabolism. The structural genes encoding the different steps of hexuronate catabolism were identified by analysis of numerous mutants affected for growth with galacturonate or glucuronate. E. coli is able to use the diacid sugars D-glucarate and galactarate (an achiral compound) as sole carbon source for growth. Pyruvate and 2-phosphoglycerate are the final products of the D-glucarate/galactarate catabolism.
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Abstract
The most common prokaryotic signal transduction mechanisms are the one-component systems in which a single polypeptide contains both a sensory domain and a DNA-binding domain. Among the >20 classes of one-component systems, the TetR family of regulators (TFRs) are widely associated with antibiotic resistance and the regulation of genes encoding small-molecule exporters. However, TFRs play a much broader role, controlling genes involved in metabolism, antibiotic production, quorum sensing, and many other aspects of prokaryotic physiology. There are several well-established model systems for understanding these important proteins, and structural studies have begun to unveil the mechanisms by which they bind DNA and recognize small-molecule ligands. The sequences for more than 200,000 TFRs are available in the public databases, and genomics studies are identifying their target genes. Three-dimensional structures have been solved for close to 200 TFRs. Comparison of these structures reveals a common overall architecture of nine conserved α helices. The most important open question concerning TFR biology is the nature and diversity of their ligands and how these relate to the biochemical processes under their control.
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Al-Turki A, El-Ziney M. Evaluation of Commercial Colilert18-Quantitray® Method by ISO Techniques for Enumeration and Quantification of Total Coliforms and Escherichia coli in Drinking-Water of Buraidah, Saudi Arabia. ACTA ACUST UNITED AC 2009. [DOI: 10.3923/jas.2009.3357.3363] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Brady SF, Clardy J. Systematic investigation of the Escherichia coli metabolome for the biosynthetic origin of an isocyanide carbon atom. Angew Chem Int Ed Engl 2006; 44:7045-8. [PMID: 16217820 DOI: 10.1002/anie.200501942] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Sean F Brady
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA.
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Brady SF, Clardy J. Systematic Investigation of theEscherichia coli Metabolome for the Biosynthetic Origin of an Isocyanide Carbon Atom. Angew Chem Int Ed Engl 2005. [DOI: 10.1002/ange.200501942] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Beaud D, Tailliez P, Anba-Mondoloni J. Genetic characterization of the β-glucuronidase enzyme from a human intestinal bacterium, Ruminococcus gnavus. Microbiology (Reading) 2005; 151:2323-2330. [PMID: 16000722 DOI: 10.1099/mic.0.27712-0] [Citation(s) in RCA: 103] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
β-Glucuronidase activity (encoded by thegusgene) has been characterized for the first time fromRuminococcus gnavusE1, an anaerobic bacterium belonging to the dominant human gut microbiota.β-Glucuronidase activity plays a major role in the generation of toxic and carcinogenic metabolites in the large intestine, as well as in the absorption and enterohepatic circulation of many aglycone residues with protective effects, such as lignans, flavonoids, ceramide and glycyrrhetinic acid, that are liberated by the hydrolysis of the corresponding glucuronides. The complete nucleotide sequence of a 4537 bp DNA fragment containing theβ-glucuronidase locus fromR. gnavusE1 was determined. Five ORFs were detected on this fragment: three complete ORFs (ORF2,gusand ORF3) and two partial ORFs (ORF4 and ORF5). The products of ORF2 and ORF3 show strong similarities with manyβ-glucoside permeases of the phosphoenolpyruvate : β-glucoside phosphotransferase systems (PTSs), such asEscherichia coliBglC,Bacillus subtilisBglP andBacillus haloduransPTS Enzyme II. The product of ORF5 presents strong similarities with the amino-terminal domain ofClostridium acetobutylicumβ-glucosidase (bglA). Thegusgene product presents similarities with several knownβ-glucuronidase enzymes, including those ofLactobacillus gasseri(69 %),E. coli(61 %),Clostridium perfringens(59 %) andStaphylococcus aureus(58 %). By complementing anE. colistrain in which theuidAgene encoding the enzyme was deleted, it was confirmed that theR. gnavus gusgene encodes theβ-glucuronidase enzyme. Moreover, it was found that thegusgene was transcribed as part of an operon that includes ORF2, ORF3 and ORF5.
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Affiliation(s)
- Diane Beaud
- Unité d'Ecologie et de Physiologie du Système Digestif, Institut National de la Recherche Agronomique, Domaine de Vilvert, 78352 Jouy-en-Josas, France
| | - Patrick Tailliez
- Unité d'Ecologie et de Physiologie du Système Digestif, Institut National de la Recherche Agronomique, Domaine de Vilvert, 78352 Jouy-en-Josas, France
| | - Jamila Anba-Mondoloni
- Unité d'Ecologie et de Physiologie du Système Digestif, Institut National de la Recherche Agronomique, Domaine de Vilvert, 78352 Jouy-en-Josas, France
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Liang WJ, Wilson KJ, Xie H, Knol J, Suzuki S, Rutherford NG, Henderson PJF, Jefferson RA. The gusBC genes of Escherichia coli encode a glucuronide transport system. J Bacteriol 2005; 187:2377-85. [PMID: 15774881 PMCID: PMC1065211 DOI: 10.1128/jb.187.7.2377-2385.2005] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Two genes, gusB and gusC, from a natural fecal isolate of Escherichia coli are shown to encode proteins responsible for transport of beta-glucuronides with synthetic [(14)C]phenyl-1-thio-beta-d-glucuronide as the substrate. These genes are located in the gus operon downstream of the gusA gene on the E. coli genome, and their expression is induced by a variety of beta-d-glucuronides. Measurements of transport in right-side-out subcellular vesicles show the system has the characteristics of secondary active transport energized by the respiration-generated proton motive force. When the genes were cloned together downstream of the tac operator-promoter in the plasmid pTTQ18 expression vector, transport activity was increased considerably with isopropylthiogalactopyranoside as the inducer. Amplified expression of the GusB and GusC proteins enabled visualization and identification by N-terminal sequencing of both proteins, which migrated at ca. 32 kDa and 44 kDa, respectively. Separate expression of the GusB protein showed that it is essential for glucuronide transport and is located in the inner membrane, while the GusC protein does not catalyze transport but assists in an as yet unknown manner and is located in the outer membrane. The output of glucuronides as waste by mammals and uptake for nutrition by gut bacteria or reabsorption by the mammalian host is discussed.
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Affiliation(s)
- Wei-Jun Liang
- Astbury Centre for Structural Molecular Biology, School of Biochemistry and Molecular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
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Slavcev RA, Funnell BE. Identification and characterization of a novel allele of Escherichia coli dnaB helicase that compromises the stability of plasmid P1. J Bacteriol 2005; 187:1227-37. [PMID: 15687186 PMCID: PMC545633 DOI: 10.1128/jb.187.4.1227-1237.2005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bacteriophage P1 lysogenizes Escherichia coli cells as a plasmid with approximately the same copy number as the copy number of the host chromosome. Faithful inheritance of the plasmids relies upon proper DNA replication, as well as a partition system that actively segregates plasmids to new daughter cells. We genetically screened for E. coli chromosomal mutations that influenced P1 stability and identified a novel temperature-sensitive allele of the dnaB helicase gene (dnaB277) that replaces serine 277 with a leucine residue (DnaB S277L). This allele conferred a severe temperature-sensitive phenotype to the host; dnaB277 cells were not viable at temperatures above 34 degrees C. Shifting dnaB277 cells to 42 degrees C resulted in an immediate reduction in the rate of DNA synthesis and extensive cell filamentation. The dnaB277 allele destabilized P1 plasmids but had no significant influence on the stability of the F low-copy-number plasmid. This observation suggests that there is a specific requirement for DnaB in P1 plasmid maintenance in addition to the general requirement for DnaB as the replicative helicase during elongation.
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Affiliation(s)
- Roderick A Slavcev
- Department of Medical Genetics and Microbiology, University of Toronto, 1 Kings College Circle, Toronto, Ontario, Canada M5S 1A8
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Kreth J, Merritt J, Bordador C, Shi W, Qi F. Transcriptional analysis of mutacin I (mutA) gene expression in planktonic and biofilm cells of Streptococcus mutans using fluorescent protein and glucuronidase reporters. ORAL MICROBIOLOGY AND IMMUNOLOGY 2004; 19:252-6. [PMID: 15209996 DOI: 10.1111/j.1399-302x.2004.00148.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Streptococcus mutans is implicated as the primary pathogen involved in the development of dental caries. The production of specific bacteriocins (called mutacins) by S. mutans is one of the major virulence factors which facilitate the dominance of the bacterium within dental plaque. While much has been revealed about the biochemical structures of mutacins, little is known about the expression and regulation of mutacin genes, largely due to the lack of proper methods to monitor mutacin gene expression, especially under biofilm conditions. In this study, a set of reporter systems with the green fluorescent protein (gfp), the monomeric red fluorescent protein (mrfp1), and the glucuronidase (gusA) are introduced to S. mutans to study the transcriptional activities of the mutacin I gene (mutA). Although the mutA-reporter fusions are in single copy on the chromosome, these reporter systems display strong signals that allow us to effectively monitor mutA gene expression in S. mutans. Using these reporter systems, we show that mutA is expressed in both planktonic and biofilm cells, even though mutacin activities are normally detected only in biofilm cells. Furthermore, we confirm that mutR, the gene upstream of the mutacin operon, is required for mutacin I gene expression. The success of this study validates the feasibility of using these reporter systems to study gene expression and regulation in S. mutans.
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Affiliation(s)
- J Kreth
- Department of Oral Biology and Medicine, UCLA School of Dentistry, Los Angeles, California 90095, USA
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Russell WM, Klaenhammer TR. Identification and cloning of gusA, encoding a new beta-glucuronidase from Lactobacillus gasseri ADH. Appl Environ Microbiol 2001; 67:1253-61. [PMID: 11229918 PMCID: PMC92721 DOI: 10.1128/aem.67.3.1253-1261.2001] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The gusA gene, encoding a new beta-glucuronidase enzyme, has been cloned from Lactobacillus gasseri ADH. This is the first report of a beta-glucuronidase gene cloned from a bacterial source other than Escherichia coli. A plasmid library of L. gasseri chromosomal DNA was screened for complementation of an E. coli gus mutant. Two overlapping clones that restored beta-glucuronidase activity in the mutant strain were sequenced and revealed three complete and two partial open reading frames. The largest open reading frame, spanning 1,797 bp, encodes a 597-amino-acid protein that shows 39% identity to beta-glucuronidase (GusA) of E. coli K-12 (EC 3.2.1.31). The other two complete open reading frames, which are arranged to be separately transcribed, encode a putative bile salt hydrolase and a putative protein of unknown function with similarities to MerR-type regulatory proteins. Overexpression of GusA was achieved in a beta-glucuronidase-negative L. gasseri strain by expressing the gusA gene, subcloned onto a low-copy-number shuttle vector, from the strong Lactobacillus P6 promoter. GusA was also expressed in E. coli from a pET expression system. Preliminary characterization of the GusA protein from crude cell extracts revealed that the enzyme was active across an acidic pH range and a broad temperature range. An analysis of other lactobacilli identified beta-glucuronidase activity and gusA homologs in other L. gasseri isolates but not in other Lactobacillus species tested.
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Affiliation(s)
- W M Russell
- Department of Microbiology, Southeast Dairy Foods Research Center, North Carolina State University, Raleigh, North Carolina 27695, USA
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Abstract
This map is an update of the edition 9 map by Berlyn et al. (M. K. B. Berlyn, K. B. Low, and K. E. Rudd, p. 1715-1902, in F. C. Neidhardt et al., ed., Escherichia coli and Salmonella: cellular and molecular biology, 2nd ed., vol. 2, 1996). It uses coordinates established by the completed sequence, expressed as 100 minutes for the entire circular map, and adds new genes discovered and established since 1996 and eliminates those shown to correspond to other known genes. The latter are included as synonyms. An alphabetical list of genes showing map location, synonyms, the protein or RNA product of the gene, phenotypes of mutants, and reference citations is provided. In addition to genes known to correspond to gene sequences, other genes, often older, that are described by phenotype and older mapping techniques and that have not been correlated with sequences are included.
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Affiliation(s)
- M K Berlyn
- Department of Biology and School of Forestry and Environmental Studies, Yale University, New Haven, Connecticut 06520-8104, USA.
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Eckner KF. Comparison of membrane filtration and multiple-tube fermentation by the colilert and enterolert methods for detection of waterborne coliform bacteria, Escherichia coli, and enterococci used in drinking and bathing water quality monitoring in southern sweden. Appl Environ Microbiol 1998; 64:3079-83. [PMID: 9687478 PMCID: PMC106820 DOI: 10.1128/aem.64.8.3079-3083.1998] [Citation(s) in RCA: 112] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
A total of 338 water samples, 261 drinking water samples and 77 bathing water samples, obtained for routine testing were analyzed in duplicate by Swedish standard methods using multiple-tube fermentation or membrane filtration and by the Colilert and/or Enterolert methods. Water samples came from a wide variety of sources in southern Sweden (Skåne). The Colilert method was found to be more sensitive than Swedish standard methods for detecting coliform bacteria and of equal sensitivity for detecting Escherichia coli when all drinking water samples were grouped together. Based on these results, Swedac, the Swedish laboratory accreditation body, approved for the first time in Sweden use of the Colilert method at this laboratory for the analysis of all water sources not falling under public water regulations (A-krav). The coliform detection study of bathing water yielded anomalous results due to confirmation difficulties. E. coli detection in bathing water was similar by both the Colilert and Swedish standard methods as was fecal streptococcus and enterococcus detection by both the Enterolert and Swedish standard methods.
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Juck D, Ingram J, Prévost M, Coallier J, Greer C. Nested PCR protocol for the rapid detection of Escherichia coli in potable water. Can J Microbiol 1996; 42:862-6. [PMID: 8776856 DOI: 10.1139/m96-110] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
A rapid and sensitive method for the detection of low levels of bacteria in potable water was developed. The fecal indicator bacterium Escherichia coli was used as the test organism in a filtration concentration - nested polymerase chain reaction (PCR) protocol, combined with ethidium bromide visualization of PCR products. Two sets of primers were designed from the E. coli specific beta-glucuronidase gene (uidA), the primary pair producing a 486-bp fragment that was used as template for the nested primer pair delineating a 186-bp fragment. This protocol can detect 1-10 bacterial cells/50 mL water sample within 6-8 h, in contrast to traditional culturing or Southern hybridization methods which require 2-3 days for results.
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Affiliation(s)
- D Juck
- McGill University, Sainte-Anne-de-Bellevue, QC, Canada
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18
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Davies CM, Apte SC, Peterson SM, Stauber JL. Plant and algal interference in bacterial beta-D-galactosidase and beta-D-glucuronidase assays. Appl Environ Microbiol 1994; 60:3959-64. [PMID: 7993085 PMCID: PMC201922 DOI: 10.1128/aem.60.11.3959-3964.1994] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Several commonly occurring freshwater and marine plants and algae were screened for beta-D-galactosidase and beta-D-glucuronidase activities by using a 60-min enzyme assay based on the hydrolysis by these enzymes of 4-methylumbelliferyl-beta-D-galactoside and 4-methylumbelliferyl- beta-glucuronide, respectively. All freshwater plant extracts tested showed beta-D-galactosidase activity several at relatively high levels, and a number also showed beta-D-glucuronidase activity. A number of the macroalgae showed no activity of either enzyme, but those showing beta-D-galactosidase activity also showed beta-D-glucuronidase activity. The majority of microalgae showed some beta-D-galactosidase activity, but few showed beta-D-glucuronidase activity. Further studies, using the commercial Colilert test and the marine water formulation of Colilert, revealed that 2 of 11 of the microalgal species and several of the plant extracts tested caused positive reactions. It was concluded that several plant extracts and algae could significantly interfere with the detection of coliform bacteria and Escherichia coli with the use of rapid assays, on the basis of their production of beta-D-galactosidase and beta-D-glucuronidase, respectively. The significance of the plant and algal interferences in tests such as Colilert is dependent on the levels of enzymes released under natural conditions, the dilution which they may undergo, and the numbers of algal cells present. This also applies to interferences in rapid enzyme assays.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- C M Davies
- Centre for Advanced Analytical Chemistry, CSIRO Division of Coal and Energy Technology, Menai, New South Wales, Australia
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19
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Martins MT, Rivera IG, Clark DL, Stewart MH, Wolfe RL, Olson BH. Distribution of uidA gene sequences in Escherichia coli isolates in water sources and comparison with the expression of beta-glucuronidase activity in 4-methylumbelliferyl-beta-D-glucuronide media. Appl Environ Microbiol 1993; 59:2271-6. [PMID: 8357258 PMCID: PMC182268 DOI: 10.1128/aem.59.7.2271-2276.1993] [Citation(s) in RCA: 57] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
The uidA gene, which encodes the beta-glucuronidase enzyme, was detected in 97.7% of 435 Escherichia coli isolates from treated and raw water sources by DNA-DNA hybridization; 92.4% of the strains expressed the translational product in 4-methylumbelliferyl-beta-D-glucuronide-containing media after reinoculation. Upon initial isolation from water samples, the minimal medium o-nitrophenyl-beta-D-galactopyranoside-4-methylum-belliferyl -beta-D-glucuronide preparations failed to detect more than 50% of the E. coli isolates that possessed uidA gene. Treated water gave the lowest recovery, with Colilert producing 26% positive samples and Coliquik producing 48% positive samples. There appears to be no relationship between the intensity of the autoradiographic signals of the uidA gene and the expression of beta-glucuronidase activity. Therefore, another variable such as physiological condition of the bacteria could be responsible for the nonexpression of the enzyme activity.
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Affiliation(s)
- M T Martins
- Department of Microbiology, University of Sao Paulo, Brazil
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20
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Frampton EW, Restaino L. Methods for Escherichia coli identification in food, water and clinical samples based on beta-glucuronidase detection. THE JOURNAL OF APPLIED BACTERIOLOGY 1993; 74:223-33. [PMID: 8468256 DOI: 10.1111/j.1365-2672.1993.tb03019.x] [Citation(s) in RCA: 58] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Affiliation(s)
- E W Frampton
- Department of Biological Sciences, Northern Illinois University, DeKalb 60115
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21
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Abstract
Bacteroides fragilis and other gastrointestinal tract Bacteroides are unusual gram-negative eubacteria in that genes from other gram-negative eubacteria are not expressed when introduced into these organisms. To analyze gene expression in Bacteroides, expression vector and promoter probe (detection) vector systems were developed. The essential feature of the expression vector was the incorporation of a Bacteroides insertion sequence element, IS4351, which possesses promoter activity directed outward from its ends. Genes inserted into the multiple cloning site downstream from an IS4351 DNA fragment were readily expressed in B. fragilis. The chloramphenicol acetyltransferase (cat) structural gene from Tn9 was tested and conferred chloramphenicol resistance on B. fragilis. Both chloramphenicol resistance and CAT activity were shown to be dependent on the IS4351 promoters. Similar results were obtained with the Escherichia coli beta-glucuronidase gene (uidA) but activity was just 30% of the levels seen with cat. Two tetracycline resistance determinants, tetM from Streptococcus agalactiae and tetC from E. coli, also were examined. tetC did not result in detectable tetracycline resistance but the gram-positive tetM gene conferred high-level resistance to tetracycline and minocycline in Bacteroides hosts. Based on the cat results, promoter probe vectors containing the promoterless cat gene were constructed. These vectors were used to clone random B. fragilis promoters from partial genomic libraries and the recombinants displayed a range of CAT activities and chloramphenicol MICs in B. fragilis hosts. In addition, known E. coli promoters (Ptet, Ptac, Ptrc, Psyn, and P1P2rrnB) were tested for activity in B. fragilis. No chloramphenicol resistance or CAT activity was observed in B. fragilis with these promoters.
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Affiliation(s)
- C J Smith
- Department of Microbiology and Immunology, East Carolina University, Greenville, North Carolina 27858
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22
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Cleuziat P, Robert-Baudouy J. Specific detection of Escherichia coliand Shigellaspecies using fragments of genes coding for β-glucuronidase. FEMS Microbiol Lett 1990. [DOI: 10.1111/j.1574-6968.1990.tb03909.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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23
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Bardonnet N, Trautwetter A, Couchoux-Luthaud G, Blanco C. Plasmids with the uidA reporter gene for the detection of promoters and transcription signals. MOLECULAR & GENERAL GENETICS : MGG 1988; 212:390-2. [PMID: 2841575 DOI: 10.1007/bf00334714] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
We have constructed promoter-probe plasmids, pNB4 and pNB5, based on the promoterless gene for beta-glucuronidase (uidA) of Escherichia coli. Unique restriction sites for EcoRI, SacI, KpnI, SmaI, XmaI, XbaI, SalI, SphI and HindIII in pNB4 and for HindIII, PstI and BglII in pNB5 were included upstream of the uidA structural gene. The usefulness of these plasmids was demonstrated by cloning the promoter-operator region of the E. coli uxaB gene. We observed that expression of the uxaB-uidA operon fusion followed the transcription-regulating properties of the uxaB promoter. Another construct, pNB2, can be used to detect operator and terminator signals. Recipient cells transformed with such recombinant plasmids can be revealed by growth on medium containing a chromogenic beta-glucuronidase substrate.
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Affiliation(s)
- N Bardonnet
- Laboratoire de Microbiologie (CNRS UM 380024), I.N.S.A., Villeurbanne, France
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24
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Blanco C. Transcriptional and translational signals of the uidA gene in Escherichia coli K12. MOLECULAR & GENERAL GENETICS : MGG 1987; 208:490-8. [PMID: 2823062 DOI: 10.1007/bf00328145] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The expression of uidA is negatively controlled by the products of the uidR and uxuR genes and is sensitive to catabolite repression. The locations of the transcriptional and translational signals of uidA were determined using lac gene fusions and S1 mapping experiments. The promoter structure of uidA resembles that of a promoter activated by cAMP receptor protein (CRP); putative control regions are located at positions -10 and -35 (relative to the transcription start site), are separated by more than 17 bp and exhibit poor homology with the normally recognized consensus sequences. Moreover, 80 bp separate the promoter from the translational signals. No CRP binding site was detected in the promoter region of uidA. Two operator sites, 01 and 02, were identified: 01 has a greater affinity for the UidR repressor, whereas 02 has a greater affinity for the UxuR repressor, but the two repressor molecules are able to bind at both the 01 and 02 sites. Analysis of two operator constitutive mutations allowed the location of one of the two UidR repressor binding sites; it contains palindromic units spanning the TaqI site of the uidA control region.
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Affiliation(s)
- C Blanco
- Laboratoire de Microbiologie, I.N.S.A. de Lyon, Villeurbanne, France
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25
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Abstract
beta-glucuronidase was purified by affinity chromatography on thiophenyl-glucuronide coupled to Sepharose. The enzyme was more than 95% pure. This enzyme is a tetramer composed of identical 74 kDa monomers. The amino-terminal sequence determined was: NH2-Met-Leu-Arg-Pro-Val.
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26
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Jefferson RA, Burgess SM, Hirsh D. beta-Glucuronidase from Escherichia coli as a gene-fusion marker. Proc Natl Acad Sci U S A 1986; 83:8447-51. [PMID: 3534890 PMCID: PMC386947 DOI: 10.1073/pnas.83.22.8447] [Citation(s) in RCA: 606] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
We have developed a gene-fusion system based on the Escherichia coli beta-glucuronidase gene (uidA). The uidA gene has been cloned from E. coli K-12 and its entire nucleotide sequence has been determined. beta-Glucuronidase has been purified to homogeneity and characterized. The enzyme has a subunit molecular weight of 68,200, is very stable, and is easily and sensitively assayed using commercially available substrates. We have constructed gene fusions of the E. coli lacZ promoter and coding region with the coding region of the uidA gene that show beta-glucuronidase activity under lac control. Plasmid vectors have been constructed to facilitate the transfer of the beta-glucuronidase coding region to heterologous control regions, using many different restriction endonuclease cleavage sites. There are several biological systems in which uidA-encoded beta-glucuronidase may be an attractive alternative or complement to previously described gene-fusion markers such as beta-galactosidase or chloramphenicol acetyltransferase.
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27
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Sebastiano M, D'Alessio M, Bazzicalupo P. Beta-glucuronidase mutants of the nematode Caenorhabditis elegans. Genetics 1986; 112:459-68. [PMID: 3007276 PMCID: PMC1202757 DOI: 10.1093/genetics/112.3.459] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Using a screening procedure that is based on a histochemical stain for the enzyme beta-glucuronidase, we have isolated several mutants of the nematode Caenorhabditis elegans affected in beta-glucuronidase activity. All of the mutations fall into one complementation group and identify a new gene, gus-1, which has been mapped on the right arm of linkage group I (LG I), 1.1 map units to the left of unc-54. The mutants have no visible phenotype, and their viabilities and fertilities are unaffected. Linked revertants of two of the mutations have been isolated. They restore enzyme activity to almost wild-type levels; the beta-glucuronidase that one of the revertants produces differs from that of the wild type. We propose that gus-1 is the structural locus for beta-glucuronidase.
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28
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Ritzenthaler P, Blanco C, Mata-Gilsinger M. Genetic analysis of uxuR and exuR genes: evidence for ExuR and UxuR monomer repressors interactions. MOLECULAR & GENERAL GENETICS : MGG 1985; 199:507-11. [PMID: 3929016 DOI: 10.1007/bf00330766] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The uxuAB operon is under the dual control of uxuR- and exuR-encoded repressors whereas the exu regulon genes are regulated by the sole ExuR repressor. Mutations affecting the two exuR and uxuR regulatory genes were selected to investigate the relationship between the two repressors. The isolation of exuR and uxuR negative dominant mutations on a multicopy plasmid indicated that the active form of the two repressors was multimeric. The introduction of a uxuR negative dominant allele into a wild-type strain resulted in a significant increase in exu gene expression. This unexpected effect may have been the consequence of the formation of hybrid repressor molecules. This protein must be composed of native ExuR+ subunits aggregated with altered UxuR subunits. The same interference was observed for the exuR negative dominant allele on uxu gene derepression. The hypothesis given here implies that the two regions of the ExuR and UxuR repressors involved in the subunit aggregation present enough homologies to allow the formation of hybrid repressor molecules.
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29
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Blanco C, Ritzenthaler P, Mata-Gilsinger M. Nucleotide sequence of a regulatory region of the uidA gene in Escherichia coli K12. MOLECULAR & GENERAL GENETICS : MGG 1985; 199:101-5. [PMID: 3889544 DOI: 10.1007/bf00327517] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Multiple regulatory events are involved in the expression of the uidA gene. A regulatory region of this gene has been located on a 460 base pair Sau3A-EcoRI fragment and its nucleotide sequence was determined by the dideoxy method using pEMBL plasmids. A preliminary analysis of this sequence revealed the presence of numerous palindromic structures with some overlaps.
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30
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Blanco C, Mata-Gilsinger M, Ritzenthaler P. The use of gene fusions to study the expression of uidR, a negative regulatory gene of Escherichia coli K-12. Gene 1985; 36:159-67. [PMID: 3934044 DOI: 10.1016/0378-1119(85)90080-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The uidR regulatory gene of Escherichia coli codes for a repressor molecule that negatively controls the expression of the uidA gene. The uidR gene was fused in front of the lacZ gene in vitro on plasmid cloning vectors developed by Casadaban et al. [J. Bacteriol. 143 (1980) 971-980. The transcriptional direction of uidR was deduced from the restriction pattern and the phenotypic properties of the uidR-lacZ fusion plasmids. The gene is transcribed counterclockwise on the standard E. coli map, as is the uidA gene. The uidR-lacZ fusions were also used to examine the regulation of expression from the uidR promoter. It was observed that the uidR gene expression is repressed by its own product and is sensitive to catabolite control. The uidR-lacZ-encoded proteins of various sizes were isolated but attempts to obtain hybrid molecules possessing, in a single polypeptide, both the beta-galactosidase and UidR repressor activities were unsuccessful.
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31
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George AM, Levy SB. Amplifiable resistance to tetracycline, chloramphenicol, and other antibiotics in Escherichia coli: involvement of a non-plasmid-determined efflux of tetracycline. J Bacteriol 1983; 155:531-40. [PMID: 6348022 PMCID: PMC217720 DOI: 10.1128/jb.155.2.531-540.1983] [Citation(s) in RCA: 261] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Increasing levels of resistance to tetracycline and to a number of other unrelated antibiotics, including chloramphenicol, beta-lactams, puromycin, and nalidixic acid, occurred in Escherichia coli after 50 to 200 generations of growth in the presence of subinhibitory concentrations of tetracycline or chloramphenicol. In the absence of selective pressure, resistances fell to low levels within 100 generations of growth. This amplification of resistance was observed in laboratory and naturally occurring E. coli strains as well as in polA and recA strains. With the exception of previously identified cmlA and cmlB mutations, tetracycline or chloramphenicol resistances were not P1 transducible. Coincident with the emergence of resistance was the appearance of a previously cryptic energy-dependent efflux system for tetracycline. The expression of resistance phenotypes and the tetracycline efflux system were temperature sensitive at 42 degrees C.
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32
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Ritzenthaler P, Blanco C, Mata-Gilsinger M. Interchangeability of repressors for the control of the uxu and uid operons in E. coli K12. MOLECULAR & GENERAL GENETICS : MGG 1983; 191:263-70. [PMID: 6353163 DOI: 10.1007/bf00334824] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The uidA and uxuAB operons are each under the dual control of two repressor molecules: the uidR and uxuR encoded repressors negatively control the uidA operon whereas the uxuAB operon is regulated by the uxuR and exuR gene products. Plasmids overproducing the regulatory molecules encoded by exuR, uxuR, or uidR were used to investigate the regulation of these two operons. Large amounts of either exuR or uxuR repressor caused a complete repression of the uxuAB operon in exuR and uxuR double-deleted mutants, suggesting that the two repressors, when they are overproduced, are totally interchangeable for the control of the uxuAB operon. In contrast, the UxuR molecule has no effect on the other exu regulon operons controlled by the exuR gene product. The uidR and uxuR gene products appear to be partially interchangeable for the regulation of the uidA gene since addition of multicopy plasmids bearing uidR+, in uxuR deleted mutant strains, only partially suppresses the derepression of the uidA gene. Inversely, multicopies of uidR weakly reduced the synthesis of the uxuB gene product in uxuR derepressed mutants. The restrictions placed by these phenomena on the formulation of the mechanism of cooperation between the two repressor molecules for repressing the uxuAB and uidA operons are discussed.
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33
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Blanco C, Ritzenthaler P, Mata-Gilsinger M. Cloning and endonuclease restriction analysis of uidA and uidR genes in Escherichia coli K-12: determination of transcription direction for the uidA gene. J Bacteriol 1982; 149:587-94. [PMID: 6276362 PMCID: PMC216546 DOI: 10.1128/jb.149.2.587-594.1982] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
The two genes of the Escherichia coli K-12 uid region (the structural gene uidA and the regulatory gene uidR) were isolated on a ColE1-uid hybrid plasmid from the bank of Clarke and Carbon. We made a restriction map of this region and correlated it with the genetic map by subcloning the uid restriction fragments into plasmids pBR322, pBR325, and pACYC177. In these plasmids, amplification of the products of the uidA and uidR genes occurred. The enzyme coded for by uidA was identified by polyacrylamide gel electrophoresis of crude extracts from strains containing the uidA plasmid. A 1-megadalton EcoRI-BamHI segment contained the uidAo operator, and the direction of transcription of the uidA gene was determined. The restriction analysis also suggested that the order of the loci in this region is manA, uidA, uidAo, uidR.
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34
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Diderichsen B, De Hauwer G. Improved mapping of the tyrS locus in Escherichia coli. MOLECULAR & GENERAL GENETICS : MGG 1980; 178:647-50. [PMID: 6993861 DOI: 10.1007/bf00337873] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
A tyrosyl-tRNA synthetase mutant of Escherichia coli was isolated and the tyrS gene assigned a map position between man and pdxH at 36.0 min on the chromosome. The tyrS mutant grew badly on broth as did previously described tyrS mutants. This sensitivity to broth was suppressed by tyrR mutations. F-prime factors were found to complement the tyrS mutation.
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35
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36
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Hanson RL, Rose C. Genetic mapping of a mutation affecting pyridine nucleotide transhydrogenase in Escherichia coli. J Bacteriol 1979; 138:783-7. [PMID: 378938 PMCID: PMC218105 DOI: 10.1128/jb.138.3.783-787.1979] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
A mutation, pnt-1, causing loss of pyridine nucleotide transhydrogenase activity in Escherichia coli, was mapped by assaying for the enzyme in extracts of recombinant strains produced by conjugation, F-duction, and P1 transduction. The site of this mutation was near min 35, counterclockwise from man, and it co-transduced 59% with man. The mutation was associated with loss from the cell membrane fraction of energy-independent and adenosine 5'-triphosphate-dependent transhydrogenase activities, but reduced nicotinamide adenine dinucleotide dehydrogenase activity was not affected. Strains were constructed which lack phosphoglucoisomerase (pgi-2) and which carry either pnt+ or pnt-1. Although such strains, when grown on glucose, are expected to produce a large excess of reduced nicotinamide adenine dinucleotide phosphate, the growth rate was not affected by the pnt-1 allele.
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37
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Harayama S, Palva ET, Hazelbauer GL. Transposon-insertion mutants of Escherichia coli K12 defective in a component common to galactose and ribose chemotaxis. MOLECULAR & GENERAL GENETICS : MGG 1979; 171:193-203. [PMID: 375029 DOI: 10.1007/bf00270005] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
From a collection of 8,000 transposon-insertion mutants of Escherichia coli K12 we identified two mutations, trg-1::Tn5 and trg-2::Tn10, that simultaneously eliminate chemotactic response to ribose and galactose, two attractants recognized by independent receptors. We show that these transposon-insertions confer a Trg phenotype, indicating that this specific pattern of tactic defects is a null phenotype. The two mutation sites are cotransductionally linked to an extend consistent with placement in the same gene. The Trg phenotype of a family of deletion mutants produced by curing trg-2::Tn10 implies that trg is a single gene. Experiments with appropriate F-primes and Hfr's locate the trg locus at approximately 31 min on the linkage map, with a marker order: pyrF-rac-(P.O. 43)-trg-man. We also found one trg mutant whose Trg phenotype was not linked to a transposon-insertion but is probably the result of a mutator activity in the parent strain. Selection of transposon-insertions near, but not in trg allowed demonstration of a very close linkage between the spontaneous trg-3 and the transposon-generated trg's, indicating all three mutations are probably in the same gene. In our manipulations of transposon-insertions we found that Tn5 had a tendency to translocate from its initial site of insertion while Tn10 was relatively stable. The trg-product is probably a chemotactic signal transducer, which interacts directly with two independent receptor proteins and transmits information to the central chemotactic machinery.
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38
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Movva NR, Katz E, Asdourian PL, Hirota Y, Inouye M. Gene dosage effects of the structural gene for a lipoprotein of the Escherichia coli outer membrane. J Bacteriol 1978; 133:81-4. [PMID: 338599 PMCID: PMC221979 DOI: 10.1128/jb.133.1.81-84.1978] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The gene dosage effects of the structural gene (lpp) for the lipoprotein of the Escherichia coli outer membrane were examined. A novel F-prime factor containing the lpp gene was constructed. The amount of the free-form lipoprotein in the merodiploid strain carrying the F-prime factor was found to be about two times as great as that in the corresponding haploid strain. On the other hand, the amount of the bound-form lipoprotein, which is vovalently linked to the peptidoglycan, was not significantly different in the merodiploid strain as compared with the corresponding haploid strain. The present results suggest that the lpp gene is expressed constitutively in contrast to another major protein of the E. coli outer membrane, tolG protein (protein II, D. B. Datta et al., J. Bacteriol. 128:834-841, 1976). The F-prime factor isolated may include a portion of the E. coli chromosome (located between 33 and 36 min on the genetic map) that is not covered by any other F-prime factor.
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39
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Amemura A, Hisamatsu M, Harada T. Spontaneous mutation of polysaccharide production in Alcaligenes faecalis var. myxogenes 10C3. Appl Environ Microbiol 1977; 34:617-20. [PMID: 596866 PMCID: PMC242719 DOI: 10.1128/aem.34.6.617-620.1977] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Alcaligenes faecalis var. myxogenes 10C3, which produces large amounts of succinoglucan and small amounts of curdlan, was genetically unstable and mutated spontaneously to a form producing more curdland than succinoglucan when stocked on nutrient agar slants. The mutation occurred in the absence of cell division when the cells were incubated in saline and was enhanced by treatment with N-methyl-N'-nitro-N-nitrosoguanidine, ethyl methane sulfonate, or ultraviolet light. Mutant strains were genetically stable and did not revert spontaneously for at least 1 year when stocked on nutrient agar slants.
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40
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Mandrand-Berthelot MA, Novel G, Novel M. [Gratuitous induction of beta-glucuronidase of Escherichia coli K 12 and the double repression mechanism]. Biochimie 1977; 59:163-70. [PMID: 322730 DOI: 10.1016/s0300-9084(77)80287-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Using natural inducers of beta-glucuronidase, methyl-glucuronide and fructuronate, under gratuitous conditions (without metabolic conversion of these two compounds), we corroborate the fact that both molecules are required simultaneously in order to derepress the enzyme synthesis to a maximum level. Structurally related analogs of the natural inducers, thiophenyl-glucuronide and mannonic amide respectively, were assayed in the wild type and suitable mutant strains of E. coli. The results are in agreement with the model where the dual negative regulation of the enzyme synthesis is exerted by two regulatory genes uidR and uxuR. The concerted action of mannonic amide and thiophenyl-glucuronide, which alone fail to induce significantly beta-glucuronidase synthesis, reveals that a cooperative effect of the two repressor molecules responsible for the complete blocking of the enzyme synthesis is occuring.
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41
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Novel M, Novel G. Regulation of beta-glucuronidase synthesis in Escherichia coli K-12: pleiotropic constitutive mutations affecting uxu and uidA expression. J Bacteriol 1976; 127:418-32. [PMID: 776934 PMCID: PMC233075 DOI: 10.1128/jb.127.1.418-432.1976] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Among the beta-glucuronidase (UID)-constitutive mutants obtained by growth on methyl-beta-D-galacturonide, some strains are also derepressed for the two enzymes of the uxu operon: mannonate oxidoreductase (MOR) and mannonate hydrolyase (HLM). By conjugation and transduction experiments, two distinct constitutive mutations were separated in each pleiotropic mutant strain. One of them was specific for uidA gene expression and was characterized as affecting either uidO or uidR sites. The second type of mutation was mapped close to the uxu operon and was found to be responsible for the pleiotropic effect revealed in the primary mutants: after separation such a mutation still fully derepresses MOR and HLM synthesis but weakly derepresses UID synthesis. The pleiotropic effect of this mutation was maintained even though the activity of the structural genes was altered. This rules out the occurrence of an internal derepressing interaction between these enzymes. In merodiploid strains, uxu-linked constitutive mutations were recessive to the wild-type allele, suggesting that these mutations could affect a regulatory gene. The uxuR gene is probably a specific regulatory gene for a very close operon, uxu. Moreover, it has a weak effect on uidA expression. Thus, UID synthesis would be negatively controlled through the activity of two repressor molecules that are synthesized by two distinct regulatory genes, uidR and uxuR. These two repressing factors are antagonized, respectively, by phenyl-thio-beta-D-glucuronide and mannonic amide and could cooperate in a unique repression/induction control over uidA expression. Constitutive mutations affecting the control sites of uidA gene probably characterize two distinct attachment sites in the operator locus for each of the repressor molecules.
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