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Giermasińska-Buczek K, Gawor J, Stefańczyk E, Gągała U, Żuchniewicz K, Rekosz-Burlaga H, Gromadka R, Łobocka M. Interaction of bacteriophage P1 with an epiphytic Pantoea agglomerans strain-the role of the interplay between various mobilome elements. Front Microbiol 2024; 15:1356206. [PMID: 38591037 PMCID: PMC10999674 DOI: 10.3389/fmicb.2024.1356206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Accepted: 02/21/2024] [Indexed: 04/10/2024] Open
Abstract
P1 is a model, temperate bacteriophage of the 94 kb genome. It can lysogenize representatives of the Enterobacterales order. In lysogens, it is maintained as a plasmid. We tested P1 interactions with the biocontrol P. agglomerans L15 strain to explore the utility of P1 in P. agglomerans genome engineering. A P1 derivative carrying the Tn9 (cmR) transposon could transfer a plasmid from Escherichia coli to the L15 cells. The L15 cells infected with this derivative formed chloramphenicol-resistant colonies. They could grow in a liquid medium with chloramphenicol after adaptation and did not contain prophage P1 but the chromosomally inserted cmR marker of P1 Tn9 (cat). The insertions were accompanied by various rearrangements upstream of the Tn9 cat gene promoter and the loss of IS1 (IS1L) from the corresponding region. Sequence analysis of the L15 strain genome revealed a chromosome and three plasmids of 0.58, 0.18, and 0.07 Mb. The largest and the smallest plasmid appeared to encode partition and replication incompatibility determinants similar to those of prophage P1, respectively. In the L15 derivatives cured of the largest plasmid, P1 with Tn9 could not replace the smallest plasmid even if selected. However, it could replace the smallest and the largest plasmid of L15 if its Tn9 IS1L sequence driving the Tn9 mobility was inactivated or if it was enriched with an immobile kanamycin resistance marker. Moreover, it could develop lytically in the L15 derivatives cured of both these plasmids. Clearly, under conditions of selection for P1, the mobility of the P1 selective marker determines whether or not the incoming P1 can outcompete the incompatible L15 resident plasmids. Our results demonstrate that P. agglomerans can serve as a host for bacteriophage P1 and can be engineered with the help of this phage. They also provide an example of how antibiotics can modify the outcome of horizontal gene transfer in natural environments. Numerous plasmids of Pantoea strains appear to contain determinants of replication or partition incompatibility with P1. Therefore, P1 with an immobile selective marker may be a tool of choice in curing these strains from the respective plasmids to facilitate their functional analysis.
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Affiliation(s)
- Katarzyna Giermasińska-Buczek
- Department of Biochemistry and Microbiology, Institute of Biology, Warsaw University of Life Sciences (SGGW-WULS), Warsaw, Poland
- Institute of Biochemistry and Biophysics of the Polish Academy of Sciences, Warsaw, Poland
| | - Jan Gawor
- Institute of Biochemistry and Biophysics of the Polish Academy of Sciences, Warsaw, Poland
| | - Emil Stefańczyk
- Institute of Biochemistry and Biophysics of the Polish Academy of Sciences, Warsaw, Poland
| | - Urszula Gągała
- Department of Biochemistry and Microbiology, Institute of Biology, Warsaw University of Life Sciences (SGGW-WULS), Warsaw, Poland
| | - Karolina Żuchniewicz
- Institute of Biochemistry and Biophysics of the Polish Academy of Sciences, Warsaw, Poland
| | - Hanna Rekosz-Burlaga
- Department of Biochemistry and Microbiology, Institute of Biology, Warsaw University of Life Sciences (SGGW-WULS), Warsaw, Poland
| | - Robert Gromadka
- Institute of Biochemistry and Biophysics of the Polish Academy of Sciences, Warsaw, Poland
| | - Małgorzata Łobocka
- Institute of Biochemistry and Biophysics of the Polish Academy of Sciences, Warsaw, Poland
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Fa-Arun J, Huan YW, Darmon E, Wang B. Tail-Engineered Phage P2 Enables Delivery of Antimicrobials into Multiple Gut Pathogens. ACS Synth Biol 2023; 12:596-607. [PMID: 36731126 PMCID: PMC9942202 DOI: 10.1021/acssynbio.2c00615] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Bacteriophages can be reprogrammed to deliver antimicrobials for therapeutic and biocontrol purposes and are a promising alternative treatment to antimicrobial-resistant bacteria. Here, we developed a bacteriophage P4 cosmid system for the delivery of a Cas9 antimicrobial into clinically relevant human gut pathogens Shigella flexneri and Escherichia coli O157:H7. Our P4 cosmid design produces a high titer of cosmid-transducing units without contamination by a helper phage. Further, we demonstrate that genetic engineering of the phage tail fiber improves the transduction efficiency of cosmid DNA in S. flexneri M90T as well as allows recognition of a nonnative host, E. coli O157:H7. We show that the transducing units with the chimeric tails enhanced the overall Cas9-mediated killing of both pathogens. This study demonstrates the potential of our P4 cas9 cosmid system as a DNA sequence-specific antimicrobial against clinically relevant gut pathogenic bacteria.
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Affiliation(s)
- Jidapha Fa-Arun
- School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FF, United Kingdom
| | - Yang Wei Huan
- School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FF, United Kingdom
| | - Elise Darmon
- School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FF, United Kingdom
| | - Baojun Wang
- College of Chemical and Biological Engineering & ZJU-Hangzhou Global Scientific and Technological Innovation Center, Zhejiang University, Hangzhou 310058, China.,School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FF, United Kingdom.,Research Center for Biological Computation, Zhejiang Laboratory, Hangzhou 311100, China
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3
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Huan YW, Fa-Arun J, Wang B. The Role of O-antigen in P1 Transduction of Shigella flexneri and Escherichia coli with its Alternative S' Tail Fibre. J Mol Biol 2022; 434:167829. [PMID: 36116540 DOI: 10.1016/j.jmb.2022.167829] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Revised: 09/03/2022] [Accepted: 09/12/2022] [Indexed: 11/30/2022]
Abstract
Enterobacteria phage P1 expresses two types of tail fibre, S and S'. Despite the wide usage of phage P1 for transduction, the host range and the receptor for its alternative S' tail fibre was never determined. Here, a ΔS-cin Δpac E. coli P1 lysogenic strain was generated to allow packaging of phagemid DNA into P1 phage having either S or S' tail fibre. P1(S') could transduce phagemid DNA into Shigella flexneri 2a 2457O, Shigella flexneri 5a M90T and Escherichia coli O3 efficiently. Mutational analysis of the O-antigen assembly genes and LPS inhibition assays indicated that P1(S') transduction requires at least one O-antigen unit. E. coli O111:B4 LPS produced a high neutralising effect against P1(S') transduction, indicating that this E. coli strain could be susceptible to P1(S')-mediated transduction. Mutations in the O-antigen modification genes of S. flexneri 2a 2457O and S. flexneri 5a M90T did not cause significant changes to P1(S') transduction efficiency. A higher transduction efficiency of P1(S') improved the delivery of a cas9 antimicrobial phagemid into both S. flexneri 2457O and M90T. These findings provide novel insights into P1 tropism-switching, by identifying the bacterial strains which are susceptible to P1(S')-mediated transduction, as well as demonstrating its potential for delivering a DNA sequence-specific Cas9 antimicrobial into clinically relevant S. flexneri.
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Affiliation(s)
- Yang W Huan
- Centre for Synthetic and Systems Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FF, United Kingdom
| | - Jidapha Fa-Arun
- Centre for Synthetic and Systems Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FF, United Kingdom
| | - Baojun Wang
- College of Chemical and Biological Engineering & ZJU-Hangzhou Global Scientific and Technological Innovation Center, Zhejiang University, Hangzhou 310058, China; Research Centre of Biological Computation, Zhejiang Laboratory, Hangzhou 311100, China.
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4
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Interactions between Viral Regulatory Proteins Ensure an MOI-Independent Probability of Lysogeny during Infection by Bacteriophage P1. mBio 2021; 12:e0101321. [PMID: 34517752 PMCID: PMC8546580 DOI: 10.1128/mbio.01013-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Phage P1 is a temperate phage which makes the lytic or lysogenic decision upon infecting bacteria. During the lytic cycle, progeny phages are produced and the cell lyses, and in the lysogenic cycle, P1 DNA exists as a low-copy-number plasmid and replicates autonomously. Previous studies at the bulk level showed that P1 lysogenization was independent of multiplicity of infection (MOI; the number of phages infecting a cell), whereas lysogenization probability of the paradigmatic phage λ increases with MOI. However, the mechanism underlying the P1 behavior is unclear. In this work, using a fluorescent reporter system, we demonstrated this P1 MOI-independent lysogenic response at the single-cell level. We further observed that the activity of the major repressor of lytic functions (C1) is a determining factor for the final cell fate. Specifically, the repression activity of P1, which arises from a combination of C1, the anti-repressor Coi, and the corepressor Lxc, remains constant for different MOI, which results in the MOI-independent lysogenic response. Additionally, by increasing the distance between phages that infect a single cell, we were able to engineer a λ-like, MOI-dependent lysogenization upon P1 infection. This suggests that the large separation of coinfecting phages attenuates the effective communication between them, allowing them to make decisions independently of each other. Our work establishes a highly quantitative framework to describe P1 lysogeny establishment. This system plays an important role in disseminating antibiotic resistance by P1-like plasmids and provides an alternative to the lifestyle of phage λ.
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Abstract
Accumulation of phosphorylated intermediates during cellular metabolism can have wide-ranging toxic effects on many organisms, including humans and the pathogens that infect them. These toxicities can be induced by feeding an upstream metabolite (a sugar, for instance) while simultaneously blocking the appropriate metabolic pathway with either a mutation or an enzyme inhibitor. Here, we survey the toxicities that can arise in the metabolism of glucose, galactose, fructose, fructose-asparagine, glycerol, trehalose, maltose, mannose, mannitol, arabinose, and rhamnose. Select enzymes in these metabolic pathways may serve as novel therapeutic targets. Some are conserved broadly among prokaryotes and eukaryotes (e.g., glucose and galactose) and are therefore unlikely to be viable drug targets. However, others are found only in bacteria (e.g., fructose-asparagine, rhamnose, and arabinose), and one is found in fungi but not in humans (trehalose). We discuss what is known about the mechanisms of toxicity and how resistance is achieved in order to identify the prospects and challenges associated with targeted exploitation of these pervasive metabolic vulnerabilities.
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Zaworski J, Dagva O, Kingston AW, Fomenkov A, Morgan RD, Bossi L, Raleigh EA. Genome archaeology of two laboratory Salmonella enterica enterica sv Typhimurium. G3 (BETHESDA, MD.) 2021; 11:jkab226. [PMID: 34544129 PMCID: PMC8496262 DOI: 10.1093/g3journal/jkab226] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Accepted: 06/29/2021] [Indexed: 11/25/2022]
Abstract
The Salmonella research community has used strains and bacteriophages over decades, exchanging useful new isolates among laboratories for the study of cell surface antigens, metabolic pathways and restriction-modification (RM) studies. Here we present the sequences of two laboratory Salmonella strains (STK005, an isolate of LB5000; and its descendant ER3625). In the ancestry of LB5000, segments of ∼15 and ∼42 kb were introduced from Salmonella enterica sv Abony 803 into S. enterica sv Typhimurium LT2, forming strain SD14; this strain is thus a hybrid of S. enterica isolates. Strains in the SD14 lineage were used to define flagellar antigens from the 1950s to the 1970s, and to define three RM systems from the 1960s to the 1980s. LB5000 was also used as a host in phage typing systems used by epidemiologists. In the age of cheaper and easier sequencing, this resource will provide access to the sequence that underlies the extensive literature.
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Affiliation(s)
- Julie Zaworski
- Research Department, New England Biolabs, Ipswich, MA 01938-2723, USA
| | - Oyut Dagva
- Research Department, New England Biolabs, Ipswich, MA 01938-2723, USA
| | | | - Alexey Fomenkov
- Research Department, New England Biolabs, Ipswich, MA 01938-2723, USA
| | - Richard D Morgan
- Research Department, New England Biolabs, Ipswich, MA 01938-2723, USA
| | - Lionello Bossi
- CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), University Paris-Saclay, Gif-sur-Yvette 91198, France
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7
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Abstract
Bacteriophages (phages) are ubiquitous in nature. These viruses play a number of central roles in microbial ecology and evolution by, for instance, promoting horizontal gene transfer (HGT) among bacterial species. The ability of phages to mediate HGT through transduction has been widely exploited as an experimental tool for the genetic study of bacteria. As such, bacteriophage P1 represents a prototypical generalized transducing phage with a broad host range that has been extensively employed in the genetic manipulation of Escherichia coli and a number of other model bacterial species. Here we demonstrate that P1 is capable of infecting, lysogenizing, and promoting transduction in members of the bacterial genus Sodalis, including the maternally inherited insect endosymbiont Sodalis glossinidius. While establishing new tools for the genetic study of these bacterial species, our results suggest that P1 may be used to deliver DNA to many Gram-negative endosymbionts in their insect host, thereby circumventing a culturing requirement to genetically manipulate these organisms. IMPORTANCE A large number of economically important insects maintain intimate associations with maternally inherited endosymbiotic bacteria. Due to the inherent nature of these associations, insect endosymbionts cannot be usually isolated in pure culture or genetically manipulated. Here we use a broad-host-range bacteriophage to deliver exogenous DNA to an insect endosymbiont and a closely related free-living species. Our results suggest that broad-host-range bacteriophages can be used to genetically alter insect endosymbionts in their insect host and, as a result, bypass a culturing requirement to genetically alter these bacteria.
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Hantke K. Compilation of Escherichia coli K-12 outer membrane phage receptors - their function and some historical remarks. FEMS Microbiol Lett 2021; 367:5721240. [PMID: 32009155 DOI: 10.1093/femsle/fnaa013] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Accepted: 01/31/2020] [Indexed: 02/07/2023] Open
Abstract
Many Escherichia coli phages have been sequenced, but in most cases their sequences alone do not suffice to predict their host specificity. Analysis of phage resistant E. coli K-12 mutants have uncovered a certain set of outer membrane proteins and polysaccharides as receptors. In this review, a compilation of E. coli K12 phage receptors is provided and their functional characterization, often driven by studies on phage resistant mutants, is discussed in the historical context. While great progress has been made in this field thus far, several proteins in the outer membrane still await characterization as phage receptors.
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Affiliation(s)
- Klaus Hantke
- IMIT, Interfakultäres Institut für Mikrobiologie und Infektionsmedizin University of Tübingen, Auf der Morgenstelle 28, 72076 Tübingen, Germany
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9
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Mutalik VK, Adler BA, Rishi HS, Piya D, Zhong C, Koskella B, Kutter EM, Calendar R, Novichkov PS, Price MN, Deutschbauer AM, Arkin AP. High-throughput mapping of the phage resistance landscape in E. coli. PLoS Biol 2020; 18:e3000877. [PMID: 33048924 PMCID: PMC7553319 DOI: 10.1371/journal.pbio.3000877] [Citation(s) in RCA: 66] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2020] [Accepted: 09/08/2020] [Indexed: 12/18/2022] Open
Abstract
Bacteriophages (phages) are critical players in the dynamics and function of microbial communities and drive processes as diverse as global biogeochemical cycles and human health. Phages tend to be predators finely tuned to attack specific hosts, even down to the strain level, which in turn defend themselves using an array of mechanisms. However, to date, efforts to rapidly and comprehensively identify bacterial host factors important in phage infection and resistance have yet to be fully realized. Here, we globally map the host genetic determinants involved in resistance to 14 phylogenetically diverse double-stranded DNA phages using two model Escherichia coli strains (K-12 and BL21) with known sequence divergence to demonstrate strain-specific differences. Using genome-wide loss-of-function and gain-of-function genetic technologies, we are able to confirm previously described phage receptors as well as uncover a number of previously unknown host factors that confer resistance to one or more of these phages. We uncover differences in resistance factors that strongly align with the susceptibility of K-12 and BL21 to specific phage. We also identify both phage-specific mechanisms, such as the unexpected role of cyclic-di-GMP in host sensitivity to phage N4, and more generic defenses, such as the overproduction of colanic acid capsular polysaccharide that defends against a wide array of phages. Our results indicate that host responses to phages can occur via diverse cellular mechanisms. Our systematic and high-throughput genetic workflow to characterize phage-host interaction determinants can be extended to diverse bacteria to generate datasets that allow predictive models of how phage-mediated selection will shape bacterial phenotype and evolution. The results of this study and future efforts to map the phage resistance landscape will lead to new insights into the coevolution of hosts and their phage, which can ultimately be used to design better phage therapeutic treatments and tools for precision microbiome engineering.
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Affiliation(s)
- Vivek K. Mutalik
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, California, United States of America
- Innovative Genomics Institute, Berkeley, California, United States of America
| | - Benjamin A. Adler
- Innovative Genomics Institute, Berkeley, California, United States of America
- Department of Bioengineering, University of California – Berkeley, Berkeley, California, United States of America
| | - Harneet S. Rishi
- Biophysics Graduate Group, University of California – Berkeley, Berkeley, California, United States of America
- Designated Emphasis Program in Computational and Genomic Biology, University of California – Berkeley, Berkeley, California, United States of America
| | - Denish Piya
- Innovative Genomics Institute, Berkeley, California, United States of America
- Department of Bioengineering, University of California – Berkeley, Berkeley, California, United States of America
| | - Crystal Zhong
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, California, United States of America
| | - Britt Koskella
- Department of Integrative Biology, University of California – Berkeley, Berkeley, California, United States of America
| | | | - Richard Calendar
- Department of Molecular and Cell Biology, University of California – Berkeley, Berkeley, California, United States of America
| | - Pavel S. Novichkov
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, California, United States of America
| | - Morgan N. Price
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, California, United States of America
| | - Adam M. Deutschbauer
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, California, United States of America
- Innovative Genomics Institute, Berkeley, California, United States of America
- Department of Plant and Microbial Biology, University of California – Berkeley, Berkeley, California, United States of America
| | - Adam P. Arkin
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, California, United States of America
- Innovative Genomics Institute, Berkeley, California, United States of America
- Department of Bioengineering, University of California – Berkeley, Berkeley, California, United States of America
- Biophysics Graduate Group, University of California – Berkeley, Berkeley, California, United States of America
- Designated Emphasis Program in Computational and Genomic Biology, University of California – Berkeley, Berkeley, California, United States of America
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10
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Genome-wide screens reveal Escherichia coli genes required for growth of T1-like phage LL5 and V5-like phage LL12. Sci Rep 2020; 10:8058. [PMID: 32415154 PMCID: PMC7229145 DOI: 10.1038/s41598-020-64981-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Accepted: 04/17/2020] [Indexed: 01/08/2023] Open
Abstract
The host factor requirements of phages and mechanisms of mutational phage insensitivity must be characterized for rational design of phage cocktails. To characterize host dependencies of two novel Escherichia coli phages, the T1-like siphophage LL5 and the V5-like myophage LL12, forward genetic screens were conducted against the Keio collection, a library of single non-essential gene deletions in E. coli str. BW25113. These screens and subsequent experiments identified genes required by phages LL5 and LL12. E. coli mutants deficient in heptose II and the phosphoryl substituent of heptose I of the inner core lipopolysaccharide (LPS) were unable to propagate phage LL5, as were mutants deficient in the outer membrane protein TolC. Mutants lacking glucose I of the LPS outer core failed to propagate LL12. Two additional genes encoding cytoplasmic chaperones, PpiB and SecB, were found to be required for efficient propagation of phage LL5, but not LL12. This screening approach may be useful for identifying host factors dependencies of phages, which would provide valuable information for their potential use as therapeutics and for phage engineering.
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11
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Riquelme NA, Leon MF, Santander JA, Robeson JP. Productive infection and transduction by bacteriophage P1 in the species Salmonella bongori. ELECTRON J BIOTECHN 2019. [DOI: 10.1016/j.ejbt.2019.04.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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12
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Genetic manipulation of pathogenicity loci in non-Typhimurium Salmonella. J Microbiol Methods 2012; 91:477-82. [PMID: 23041268 DOI: 10.1016/j.mimet.2012.09.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Revised: 09/12/2012] [Accepted: 09/12/2012] [Indexed: 11/22/2022]
Abstract
The traditional genetic tools used in Salmonella enterica serovar Typhimurium rely heavily on a high-transducing mutant of bacteriophage P22. P22 recognizes its hosts by the structure of their O-antigens, which vary among serovars of Salmonella; therefore, it cannot be used in most non-Typhimurium Salmonella, including the majority of those causing food-borne illnesses in both humans and livestock. Bacteriophage P1 infects a variety of enteric bacteria, including galE mutants of serovar Typhimurium; however, the degree to which the presence of coimmune prophages, the lack of required attachment sites or the lack of host factors act as barriers to using phage P1 in natural isolates of Salmonella is unknown. Here, we show that recombineering can be used to make virtually any serovar of Salmonella susceptible to P1 infection; as a result, P1 can be utilized for facile genetic manipulation of non-Typhimurium Salmonella, including movement of very large pathogenicity islands. A toolkit for easy manipulation of non-Typhimurium serovars of Salmonella is described.
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13
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León M, Santander J, Curtiss R, Robeson J. Natural lysogenization and transduction in Salmonella enterica serovar Choleraesuis by bacteriophage P1. Res Microbiol 2012; 164:1-5. [PMID: 22995628 DOI: 10.1016/j.resmic.2012.09.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2011] [Accepted: 09/05/2012] [Indexed: 11/15/2022]
Abstract
It has been reported that bacteriophage P1 injects DNA into serovar Choleraesuis without evidence of productive infection. However, we found that P1 generates progeny and is capable of transduction in serovar Choleraesuis. This is not the case with other serovars of Salmonella enterica we tested. Therefore, P1 could play a role in serovar Choleraesuis evolution and contribute to its genetic manipulation and analysis.
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Affiliation(s)
- Marcela León
- Pontificia Universidad Católica de Valparaíso, Instituto de Biología, Laboratorio de Bacteriología, Av. Universidad 330, Campus Curauma, Valparaíso, Chile
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14
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Hong Y, Cunneen MM, Reeves PR. The Wzx translocases for Salmonella enterica O-antigen processing have unexpected serotype specificity. Mol Microbiol 2012; 84:620-30. [PMID: 22497246 DOI: 10.1111/j.1365-2958.2012.08048.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Most Gram-negative bacteria have an O antigen, a polysaccharide with many repeats of a short oligosaccharide that is a part of the lipopolysaccharide, the major lipid in the outer leaflet of the outer membrane. Lipopolysaccharide is variable with 46 forms in Salmonella enterica that underpin the serotyping scheme. Repeat units are assembled on a lipid carrier that is embedded in the cell membrane, and are then translocated by the Wzx translocase from the cytoplasmic face to the outer face of the cell membrane, followed by polymerization. The O antigen is then incorporated into lipopolysaccharide and exported to the outer membrane. The Wzx translocase is widely thought to be specific only for the first sugar of the repeat unit, despite extensive variation in both O antigens and Wzx translocases. However, we found for S. enterica groups B, D2 and E that Wzx translocation exhibits significant specificity for the repeat-unit structure, as variants with single sugar differences are translocated with lower efficiency and little long-chain O antigen is produced. It appears that Wzx translocases are specific for their O antigen for normal levels of translocation.
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Affiliation(s)
- Yaoqin Hong
- School of Molecular Bioscience, The University of Sydney, Sydney, NSW, Australia
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15
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Abstract
Transduction is the process in which bacterial DNA is transferred from one bacterial cell to another by means of a phage particle. There are two types of transduction, generalized transduction and specialized transduction. In this chapter two of the best-studied systems - Escherichia coli-phage P1, and Salmonella enterica-phage P22 - are discussed from theoretical and practical perspectives.
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Affiliation(s)
- Anne Thierauf
- Department of Microbiology, University of Illinois, Urbana, IL, USA
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16
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Ho TD, Waldor MK. Enterohemorrhagic Escherichia coli O157:H7 gal mutants are sensitive to bacteriophage P1 and defective in intestinal colonization. Infect Immun 2006; 75:1661-6. [PMID: 17158899 PMCID: PMC1865682 DOI: 10.1128/iai.01342-06] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Enterohemorrhagic Escherichia coli (EHEC), especially E. coli O157:H7, is an emerging cause of food-borne illness. Unfortunately, E. coli O157 cannot be genetically manipulated using the generalized transducing phage P1, presumably because its extensive O antigen obscures the P1 receptor, the lipopolysaccharide (LPS) core subunit. The GalE, GalT, GalK, and GalU proteins are necessary for modifying galactose before it can be assembled into the repeating subunit of the O antigen. Here, we constructed E. coli O157:H7 gal mutants which presumably have little or no O antigen. These strains were able to adsorb P1. P1 lysates grown on the gal mutant strains could be used to move chromosomal markers between EHEC strains, thereby facilitating genetic manipulation of E. coli O157:H7. The gal mutants could easily be reverted to a wild-type Gal(+) strain using P1 transduction. We found that the O157:H7 galETKM::aad-7 deletion strain was 500-fold less able to colonize the infant rabbit intestine than the isogenic Gal(+) parent, although it displayed no growth defect in vitro. Furthermore, in vivo a Gal(+) revertant of this mutant outcompeted the galETKM deletion strain to an extent similar to that of the wild type. This suggests that the O157 O antigen is an important intestinal colonization factor. Compared to the wild type, EHEC gal mutants were 100-fold more sensitive to a peptide derived from bactericidal permeability-increasing protein, a bactericidal protein found on the surface of intestinal epithelial cells. Thus, one way in which the O157 O antigen may contribute to EHEC intestinal colonization is to promote resistance to host-derived antimicrobial polypeptides.
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Affiliation(s)
- Theresa Deland Ho
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, 136 Harrison Avenue, Boston, MA 02111, USA
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Li Q, Reeves PR. Genetic variation of dTDP-L-rhamnose pathway genes in Salmonella enterica. MICROBIOLOGY (READING, ENGLAND) 2000; 146 ( Pt 9):2291-2307. [PMID: 10974117 DOI: 10.1099/00221287-146-9-2291] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The genetic variation in the dTDP-L-rhamnose pathway gene set (rmlB, rmlD, rmlA, rmlC) in Salmonella enterica was examined after sequencing the four genes from 11 rml-containing gene clusters encoding seven O antigens, and a 903 bp rmlB segment from another 23 strains representing the seven subspecies. There was considerable sequence variation and strong polarity in the nature and level of variation among rml genes. The 5' end of the rml gene set, including rmlB, rmlD and most of rmlA, is in general subspecies specific. In contrast, the 3' end, including part of rmlA and all of rmlC, is O antigen specific. The G+C content of the 3' end is lower than that of the 5' end. The variation in the 3' end of the gene set is much greater than that of the 5' end. It is apparent that the rml gene set of S. enterica includes genes with two different evolutionary histories. In addition, there has been extensive recombination in the gene set, probably related to O antigen transfer between subspecies. These findings provide evidence for the lateral transfer of O antigen genes between species and among subspecies of S. enterica. The results have also shown that conserved genes at the end of an O antigen gene cluster play a major role in mediating exchange of the central serogroup-specific regions.
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Affiliation(s)
- Qun Li
- Department of Microbiology (G08), University of Sydney, NSW 2006, Australia1
| | - Peter R Reeves
- Department of Microbiology (G08), University of Sydney, NSW 2006, Australia1
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18
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Jackson CJ, Fox AJ, Jones DM, Wareing DR, Hutchinson DN. Associations between heat-stable (O) and heat-labile (HL) serogroup antigens of Campylobacter jejuni: evidence for interstrain relationships within three O/HL serovars. J Clin Microbiol 1998; 36:2223-8. [PMID: 9665996 PMCID: PMC105019 DOI: 10.1128/jcm.36.8.2223-2228.1998] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
A comparative examination of the heat-stable (O) and heat-labile (HL) serogrouping results for 9,024 sporadic human isolates of Campylobacter jejuni revealed conserved associations between specific O and HL antigens (O/HL serovars). Forty-nine percent of the isolates which grouped for both O and HL antigens belonged to one of three serovars: O 4 complex/HL 1 (17.9%), O 1/HL 2 (16.8%), or O 50/HL 7 (14.5%). Other common serovars were O 2/HL 4 (8.3%), O 6/HL 6 (8.1%), O 53/HL 11 (4.5%), O 19/HL 17 (3.3%), O 5/HL 9 (3.3%), O 9/HL 9 (3.2%), and O 23/HL 5 (3.1%). These 10 serovars accounted for 83.1% of the serogroupable isolates. A large number of strains (41.3%) could be typed by only one of the two methods or could not be serogrouped (11%). Strains belonging to three serovars, O 2/HL 4, O 50/HL 7, and O 23/HL 5, were further characterized by combining data from expressed features (O/HL serogroups, phage groups, and biotypes) with restriction fragment length polymorphism genotypes. These polyphasic data demonstrated that within each serovar, individual isolates showed substantial conservation of both genomic and phenotypic characteristics. The essentially clonal nature of the three serovars confirmed the potential of combined O and HL serogrouping as a practical and phylogenetically valid method for investigating the epidemiology of sporadic C. jejuni infection.
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Affiliation(s)
- C J Jackson
- Public Health Laboratory, Withington Hospital, Manchester, United Kingdom.
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19
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Curd H, Liu D, Reeves PR. Relationships among the O-antigen gene clusters of Salmonella enterica groups B, D1, D2, and D3. J Bacteriol 1998; 180:1002-7. [PMID: 9473060 PMCID: PMC106985 DOI: 10.1128/jb.180.4.1002-1007.1998] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The O antigen is an important cell wall antigen of gram-negative bacteria, and the genes responsible for its biosynthesis are located in a gene cluster. We have cloned and sequenced the DNA segment unique to the O-antigen gene cluster of Salmonella enterica group D3. This segment includes a novel O-antigen polymerase gene (wzyD3). The polymerase gives alpha(1-->6) linkages but has no detectable sequence similarity to that of group D2, which confers the same linkage. We find the remnant of a D3-like wzy gene in the O-antigen gene clusters of groups D1 and B and suggest that this is the original wzy gene of these O-antigen gene clusters.
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Affiliation(s)
- H Curd
- Department of Microbiology, The University of Sydney, New South Wales, Australia
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20
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Franco AV, Liu D, Reeves PR. A Wzz (Cld) protein determines the chain length of K lipopolysaccharide in Escherichia coli O8 and O9 strains. J Bacteriol 1996; 178:1903-7. [PMID: 8606163 PMCID: PMC177884 DOI: 10.1128/jb.178.7.1903-1907.1996] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The modal distribution of O-antigen chain length is determined by the Wzz (Cld/Rol) protein in those cases in which it has been studied. The system of O-antigen synthesis in Escherichia coli serotypes O8 and O9 is different from that reported for most other bacteria, and chain length distribution is thought not to be determined by a Wzz protein. We report the existence in E. coli O8 and O9 strains of wzz genes which are very similar to and have sequences within the range of variation of those which determine the chain length of typical O antigens. We also find that wzz genes previously identified by their effect on O-antigen chain length, when cloned and transferred to O8 and O9 strains, affect the chain length of a capsule-related form of LPS, K(LPS). We conclude that in at least some O8 and O9 strains there is a wzz gene which controls the chain length of K(LPS) but has no effect on the O8 or O9 antigen.
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Affiliation(s)
- A V Franco
- Department of Microbiology, University of Sydney, New South Wales, Australia
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21
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Ayers DJ, Sunshine MG, Six EW, Christie GE. Mutations affecting two adjacent amino acid residues in the alpha subunit of RNA polymerase block transcriptional activation by the bacteriophage P2 Ogr protein. J Bacteriol 1994; 176:7430-8. [PMID: 8002564 PMCID: PMC197197 DOI: 10.1128/jb.176.24.7430-7438.1994] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The bacteriophage P2 ogr gene product is a positive regulator of transcription from P2 late promoters. The ogr gene was originally defined by compensatory mutations that overcame the block to P2 growth imposed by a host mutation, rpoA109, in the gene encoding the alpha subunit of RNA polymerase. DNA sequence analysis has confirmed that this mutation affects the C-terminal region of the alpha subunit, changing a leucine residue at position 290 to a histidine (rpoAL290H). We have employed a reporter plasmid system to screen other, previously described, rpoA mutants for effects on activation of a P2 late promoter and have identified a second allele, rpoA155, that blocks P2 late transcription. This mutation lies just upstream of rpoAL290H, changing the leucine residue at position 289 to a phenylalanine (rpoAL289F). The effect of the rpoAL289F mutation is not suppressed by the rpoAL290H-compensatory P2 ogr mutation. P2 ogr mutants that overcome the block imposed by rpoAL289F were isolated and characterized. Our results are consistent with a direct interaction between Ogr and the alpha subunit of RNA polymerase and support a model in which transcription factor contact sites within the C terminus of alpha are discrete and tightly clustered.
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Affiliation(s)
- D J Ayers
- Department of Microbiology, Virginia Commonwealth University, Richmond
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22
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Wang L, Reeves PR. Involvement of the galactosyl-1-phosphate transferase encoded by the Salmonella enterica rfbP gene in O-antigen subunit processing. J Bacteriol 1994; 176:4348-56. [PMID: 7517393 PMCID: PMC205648 DOI: 10.1128/jb.176.14.4348-4356.1994] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
rfbT of Salmonella enterica LT2 was previously thought, together with rfaL, to be involved in the ligation of polymerized O antigen to core-lipid A, and three mutants were known. We report the mapping of the mutations to rfbP, the galactosyl-1-phosphate transferase gene, which is now shown to encode a bifunctional protein. The mutations which have the former rfbT phenotype are referred to as rfbP(T). We also show that rfbP(T) mutants are not blocked in the ligation step as previously believed but in an earlier step, possibly in flipping the O-antigen subunit on undecaprenyl pyrophosphate from the cytoplasmic to periplasmic face of the cytoplasmic membrane.
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Affiliation(s)
- L Wang
- Department of Microbiology, University of Sydney, New South Wales, Australia
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23
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Abstract
A cosmid (pPR1347) carrying both the rfb gene cluster and the rfc gene of a Salmonella group B serovar has been constructed; Escherichia coli K-12 strains carrying this cosmid produce long-chain O antigen, are sensitive to phage P22, and can be transduced by P22. Some of the benefits of P22 transduction are now available for studying E. coli and potentially other genera.
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Affiliation(s)
- B L Neal
- Department of Microbiology, University of Sydney, New South Wales, Australia
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24
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Liu D, Haase AM, Lindqvist L, Lindberg AA, Reeves PR. Glycosyl transferases of O-antigen biosynthesis in Salmonella enterica: identification and characterization of transferase genes of groups B, C2, and E1. J Bacteriol 1993; 175:3408-13. [PMID: 7684736 PMCID: PMC204739 DOI: 10.1128/jb.175.11.3408-3413.1993] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
In Salmonella enterica, there is a great variety of O antigens, each consisting of a short oligosaccharide (the repeating unit) repeated many times. The O antigens differ in their sugar composition and glycosidic linkages. The genetic determinants of the O antigen are located in an rfb gene cluster, and some, including those of S. enterica O serogroups B, C2, and E1, have been cloned and sequenced. In this study of the glycosyltransferases which form the glycosidic linkages, we identify and characterize the four mannosyl and three rhamnosyl transferase genes of the three rfb gene clusters.
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Affiliation(s)
- D Liu
- Department of Microbiology, University of Sydney, New South Wales, Australia
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25
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Nnalue NA, Shnyra A, Hultenby K, Lindberg AA. Salmonella choleraesuis and Salmonella typhimurium associated with liver cells after intravenous inoculation of rats are localized mainly in Kupffer cells and multiply intracellularly. Infect Immun 1992; 60:2758-68. [PMID: 1612743 PMCID: PMC257232 DOI: 10.1128/iai.60.7.2758-2768.1992] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Male Sprague-Dawley rats were inoculated intravenously with Salmonella choleraesuis or Salmonella typhimurium and used over 3 consecutive days to produce highly enriched (greater than 95% homogenous) preparations of Kupffer and mononuclear cells (KC), liver endothelial cells (LEC), and hepatocytes. The methods involved collagenase perfusion of the liver in situ, differential centrifugation of liver cells over a Percoll gradient, and selective attachment of the cells to plastic or to culture dishes coated with collagen. The different cell preparations were then assayed for the number and location, intracellular or extracellular, of associated viable bacteria. Most of the viable bacteria recovered were associated with KC and were mainly intracellular. The intracellular bacteria in KC from rats infected with either bacterial strain increased about 20- to 50-fold over 2 days. Some of the bacteria associated with LEC and in some experiments with hepatocytes also survived treatment with gentamicin and increased in number with time. Intracellular bacteria were readily visualized in KC by light microscopy and transmission electron microscopy. On rare occasions, bacteria were seen within LEC from rats infected with S. choleraesuis but not from those infected with S. typhimurium. Microcolonies of S. typhimurium but not of S. choleraesuis were occasionally found on the surface of some LEC. Bacteria were not seen within or on the surface of hepatocytes by transmission or scanning electron microscopy. The integration of microscopic and viability data suggested that most intracellular S. choleraesuis organisms in KC had been killed whereas most intracellular S. typhimurium organisms were viable.
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Affiliation(s)
- N A Nnalue
- Department of Clinical Bacteriology F:82, Karolinska Institute, Huddinge Hospital, Sweden
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26
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Brown PK, Romana LK, Reeves PR. Cloning of the rfb gene cluster of a group C2 Salmonella strain: comparison with the rfb regions of groups B and D. Mol Microbiol 1991; 5:1873-81. [PMID: 1722557 DOI: 10.1111/j.1365-2958.1991.tb00811.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
We report the cloning and mapping of the entire rfb gene cluster of a group C2 Salmonella strain. Comparison with the rfb region of group B strain LT2 and group D strain Ty2 reveals an 11.8 kb central region of limited similarity flanked by regions of high similarity. The genes from the central region confer a group C2 O-antigen structure on a Salmonella LT2 partial delete strain. The significance of this region in relation to function and evolutionary origin is discussed. We also report evidence for the existence of an O-antigen chain-length determinant in Escherichia coli K12 and propose a model for a possible mechanism by which a preferred chain length is determined.
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Affiliation(s)
- P K Brown
- Department of Microbiology, University of Sydney, New South Wales, Australia
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27
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Abstract
The virulence of three Salmonella species strains was compared by the i.p. and i.v. routes in BALB/c mice. Salmonella choleraesuis, SL2824 (serogroup C1, O-6,7), was more virulent by the i.v. than i.p. route. A strain of S. typhimurium, SL1260 (serogroup B; O-1,4,12) was more virulent i.p. than i.v. while another strain, SL3201 (O-4,5,12) was equally virulent i.p. or i.v. The LD50 of each strain by either route correlated with the number of bacteria in the liver and spleen on day one after inoculation and thus seems determined mainly by initial bactericidal mechanisms. The rate of bacterial growth in the liver and spleen was independent of inoculation route but differed between the three strains. Salmonella choleraesuis multiplied faster than either strain of S. typhimurium. Non-virulent aromatic-dependent (aro) derivatives of these strains were tested, instead of their virulent ancestors, for survival within peritoneal macrophages in vitro. Salmonella choleraesuis SL 2824 aro and S. typhimurium SL1260 aro were much more readily killed intracellularly than S. typhimurium SL3201 aro. The data indicate that the survival and multiplication of different Salmonella serotypes or strains in vivo may depend on different critical properties or mechanisms to overcome host defenses.
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Affiliation(s)
- N A Nnalue
- Department of Microbiology and Immunology, Stanford University School of Medicine, California 94305
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28
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Jiang XM, Neal B, Santiago F, Lee SJ, Romana LK, Reeves PR. Structure and sequence of the rfb (O antigen) gene cluster of Salmonella serovar typhimurium (strain LT2). Mol Microbiol 1991; 5:695-713. [PMID: 1710759 DOI: 10.1111/j.1365-2958.1991.tb00741.x] [Citation(s) in RCA: 279] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The rfb gene cluster of Salmonella LT2 has been cloned and sequenced. The genes rfbA, rfbB, rfbD, rfbF, rfbG, rfbK, rfbM and rfbP were located individually and the gene rfbL was located outside the cluster. Approximately 16 open reading frames were found in the region which is essential for the expression of O antigen. The gene products of rfbB and rfbG were found to have homology with the group of dehydrogenase and related enzymes described previously. Analysis of the G + C ratio of the rfb cluster extended the area of low-G + C composition previously found in the sequence of rfbJ to the whole rfb gene cluster. Three to five segments with discrete G + C contents and codon adaptation indices are present in the rfb region, indicating a heterogeneous origin of these segments. Potential promoters were found near the start of the rfb region, supporting the possibility that the rfb gene cluster is an operon.
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Affiliation(s)
- X M Jiang
- Department of Microbiology, University of Sydney, New South Wales, Australia
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29
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30
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Nnalue NA, Lindberg AA. Salmonella choleraesuis strains deficient in O antigen remain fully virulent for mice by parenteral inoculation but are avirulent by oral administration. Infect Immun 1990; 58:2493-501. [PMID: 1695204 PMCID: PMC258846 DOI: 10.1128/iai.58.8.2493-2501.1990] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
O-antigen-deficient derivatives of two mouse-virulent strains of Salmonella choleraesuis (serogroup C1; O-6,7) were constructed by transduction of a long deletion of the rfb operon. Strains SN36 and SN57 were derived from the smooth ancestor SL2824, while SN37 was derived from the smooth ancestor SL2840. These rfb deletion derivatives (rfb strains) had typical bacteriophage sensitivity patterns of "rough" Salmonella strains and were at least 200,000 times more sensitive to serum than their smooth ancestors. Lipopolysaccharides (LPS) extracted from them consisted only of two low-molecular-weight bands and lacked the ladderlike pattern of bands seen in the LPS of their smooth ancestors. The LPS from the rfb strains did not react in an enzyme immunoassay with any of three monoclonal antibodies directed against different epitopes of the O-6,7 antigen but reacted well with at least one of three monoclonal antibodies specific for core epitopes. The data were consistent with inability of these strains to synthesize O-specific chains and showed that the LPS extracted from SN57 was of chemotype Ra and that from SN36 was of chemotype Rb1, while that of SN37 consisted of a mixture of the two chemotypes. The virulence of these strains was tested by various routes in BALB/c mice. All three O-antigen-deficient derivatives were about as virulent as their "smooth" ancestors by the intraperitoneal and intravenous routes (50% lethal dose, 20 to 700 bacteria) but, unlike their ancestors, were avirulent by the oral route (50% lethal dose, greater than or equal to 5 x 10(9) bacteria). This suggests that the major role of smooth LPS in the mouse virulence of S. choleraesuis is to facilitate survival in the gastrointestinal tract and eventual entry into deeper tissues.
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Affiliation(s)
- N A Nnalue
- Karolinska Institute, Department of Clinical Bacteriology, Huddinge Hospital, Sweden
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31
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Gutmann L, Agarwal M, Arthur M, Campanelli C, Goldstein R. A phasmid shuttle vector for the cloning of complex operons in Salmonella. Plasmid 1990; 23:42-58. [PMID: 2190245 DOI: 10.1016/0147-619x(90)90043-c] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Phasmid (phage plasmid hybrid) P4 vir1 can be propagated in Escherichia coli as a helper-dependent lytic phage, as a plasmid, or as a prophage. On the basis of an understanding of these modes of propagation, derivatives of P4 have been constructed for use as cloning vectors. In this report we demonstrate that phasmid P4 (i) will propagate as a helper-dependent lytic phage and as a plasmid in Salmonella spp. and (ii) can be used as a high efficiency phage shuttle vector for the reversible transfer of cloned genes between Salmonella spp. and E. coli. For both E. coli and Salmonella spp., P4 phage-mediated gene transfer proved to be only 10-fold lower than plaquing efficiency. For the case of Salmonella spp., this frequency is ca. 10(4)-fold more efficient than is typically found for the transformation of DNA molecules. The usefulness of this cloning vector system for analyses of pathogenic virulence factors is demonstrated by the cloning and expression of both the P pilus adhesin operon and the hemolysin operon of uropathogenic E. coli.
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Affiliation(s)
- L Gutmann
- Maxwell Finland Laboratory For Infectious Diseases, Boston University, School of Medicine, Massachusetts 02118
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32
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Popkin DJ, Davis VM, Prival MJ. Isolation and characterization of an isogenic set of Salmonella typhimurium strains analogous to the "Ames" tester strains. Mutat Res 1989; 224:453-64. [PMID: 2685590 DOI: 10.1016/0165-1218(89)90070-0] [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: 01/02/2023]
Abstract
The standard Ames tester strains of Salmonella typhimurium contain a number of genetic differences at loci other than his. The fact that these strains contain independently isolated uvrB-bio-gal deletions and rfa mutations implies that these are likely to vary from strain to strain. Since the strains were isolated from different parental stocks of S. typhimurium LT-2, they differ in their ability to metabolize arabinose. Other, unknown differences may exist because the isolation of some of the strains involved ultraviolet and chemical mutagenesis. We have isolated a set of isogenic S. typhimurium strains that contain the relevant genetic markers of the standard Ames tester strains. These strains all contain the same uvrB-bio-gal deletion and the same rfa mutation; they differ only in the nature of their his mutations and in the presence or absence of the plasmid pKM101. We have assessed the responsiveness of these strains to a number of mutagens and conclude that their mutagenic specificities are the same as those of the corresponding Ames strains: TA98, TA100, TA1535, TA1537 and TA1538. Therefore, the specificity of the standard Ames strains with respect to these mutagens is a result solely of the differences in the nature of their his mutations and the effects of pKM101.
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Affiliation(s)
- D J Popkin
- Genetic Toxicology Branch, Food and Drug Administration, Washington, DC 20204
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33
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Wyk P, Reeves P. Identification and sequence of the gene for abequose synthase, which confers antigenic specificity on group B salmonellae: homology with galactose epimerase. J Bacteriol 1989; 171:5687-93. [PMID: 2793832 PMCID: PMC210415 DOI: 10.1128/jb.171.10.5687-5693.1989] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The O antigen of Salmonella group B strains contains the sugar abequose, whereas those from group A and D strains contain paratose or tyvelose in its place. This is the essential difference between these Salmonella groups. Only the final step in the biosynthesis of abequose differs from that of paratose, and the abequose confers on group B strains their specific O4 antigen. The gene, rfbJ, encoding the enzyme abequose synthase for this last specific step has been cloned, identified, and sequenced and has been shown to function in group A and D strains to make them O4+. This one gene thus differentiates group B from group A or group D salmonellae. The enzyme abequose synthase appears to be related to galactose epimerase, and the significance of this is discussed. The rfbJ gene and adjacent DNA is of much lower G+C content than is usual for salmonellae, indicating that the region did not originate in a salmonella but was transferred from outside.
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Affiliation(s)
- P Wyk
- Department of Microbiology and Immunology, University of Adelaide, Australia
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34
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Verma N, Reeves P. Identification and sequence of rfbS and rfbE, which determine antigenic specificity of group A and group D salmonellae. J Bacteriol 1989; 171:5694-701. [PMID: 2793833 PMCID: PMC210416 DOI: 10.1128/jb.171.10.5694-5701.1989] [Citation(s) in RCA: 93] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Salmonella group A, group B, and group D strains have paratose, abequose, and tyvelose, respectively, as the immunodominant sugar in their O antigens, which are otherwise identical; only the final steps differ in the biosynthetic pathways of these sugars. The gene rfbJ from a group B strain, encoding abequose synthase, the final and only unique step in the biosynthesis of CDP-abequose, has been cloned and sequenced (P. Wyk and P. Reeves, J. Bacteriol. 171:5687-5693, 1989). In this study, we locate and sequence rfbS and rfbE from serovars typhi and paratyphi, representative of groups A and D. Gene rfbS is present in both groups and encodes paratose synthase, which carries out a step parallel to that of abequose synthase, but the product is CDP-paratose. The DNA and inferred amino acid sequences are compared with those of rfbJ. We conclude that the genes are homologous, but the divergence is extremely ancient. Gene rfbE encodes CDP-tyvelose epimerase, which converts CDP-paratose to CDP-tyvelose in group D strains; the gene is active in group D strains, and we find it to be present in a mutant form in group A strains. These two genes encode the steps unique to groups A and D and, like rfbJ of group B, are of low G+C content, suggesting transfer from outside of salmonellae. The evolutionary origin of these genes is discussed.
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Affiliation(s)
- N Verma
- Department of Microbiology, University of Sydney NSW, Australia
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35
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Kutsukake K, Ohya Y, Yamaguchi S, Iino T. Operon structure of flagellar genes in Salmonella typhimurium. MOLECULAR & GENERAL GENETICS : MGG 1988; 214:11-5. [PMID: 2852301 DOI: 10.1007/bf00340172] [Citation(s) in RCA: 58] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
In Salmonella typhimurium, more than 40 genes have been shown to be involved in flagellar formation and function and almost all of them have been assigned to three regions of the chromosome, termed region I, region II, and region III. In the present study, a large number of transposon-insertion mutants in these flagellar genes were isolated using Tn10 and Mud1. The flaV gene was found to be a strong hot spot for Tn10 insertion. Complementation analysis of the polarity effects exerted by the transposon-insertion mutants defined 13 different flagellar operons; 3 in region I, 4 in region II, and 6 in region III. These results are compared with the reported arrangement of the corresponding genes in Escherichia coli.
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Affiliation(s)
- K Kutsukake
- Department of Biology, Faculty of Science, University of Tokyo, Japan
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36
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Nnalue NA, Stocker BA. The effects of O-antigen character and enterobacterial common antigen content on the in vivo persistence of aromatic-dependent Salmonella sp. live-vaccine strains. Microb Pathog 1987; 3:31-44. [PMID: 2461504 DOI: 10.1016/0882-4010(87)90035-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Aromatic-dependent (aro) derivatives of Salmonella choleraesuis like aro S. typhimurium are non-virulent but, unlike them, are ineffective as live vaccines in mice, given i.p. An aro derivative of S. choleraesuis did not persist in the liver and spleen (RES) of mice after i.p. inoculation whereas a similar derivative of S. typhimurium persisted. S. choleraesuis (O group C1; O-6,7) and S. typhimurium [O group B; O-(1),4(5),12] differ in O antigen of LPS, determined by chromosomal locus, rfb. Three pairs of nearly-isogenic aro derivatives, one member O-6,7 and the other O-(1),4,(5),12, were constructed in two lines of S. typhimurium by replacement of their B-rfb genes with the C1-rfb genes of S. choleraesuis. In tests for persistence after mixed or separate i.p. inoculation of equal doses into BALB/c mice the O-(1),4,(5),12 member of each pair was recovered as CFU in the RES at ca. 100-fold greater number than the O-6,7 member at 24 hours post-inoculation and subsequently. O-6,7 derivatives of S. typhimurium constructed as described above by a simple replacement of group B with group C-rfb locus synthesise only trace (tr) amounts of enterobacterial common antigen (ECA). An ECA+ (able to make normal levels of ECA) derivative of one aro, O-6,7 S. typhimurium strain was constructed by replacement of its B-rfe locus with the C-rfe locus of S. choleraesuis. Tested by mixed inoculation i.p. this strain persisted in the RES in numbers 10-fold greater than its O-6,7 ECAtr but 5-10-fold lesser than its O-(1),4,(5),12 cousins. Thus both O-specificity and ECA contribute to the survival of salmonella species in mice as determined by in vivo persistence of non-multiplying aro derivatives.
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Affiliation(s)
- N A Nnalue
- Department of Medical Microbiology, Stanford University School of Medicine, California 94305
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Nnalue NA, Stocker BA. Test of the virulence and live-vaccine efficacy of auxotrophic and galE derivatives of Salmonella choleraesuis. Infect Immun 1987; 55:955-62. [PMID: 3104209 PMCID: PMC260444 DOI: 10.1128/iai.55.4.955-962.1987] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Aromatic compound-dependent (aro) derivatives of three mouse-virulent strains of Salmonella choleraesuis (Salmonella cholerae-suis) were constructed and shown to be nonvirulent for mice (intraperitoneal [i.p.] 50% lethal dose [LD50], greater than 5 X 10(6) CFU). A pur derivative, and a thy derivative, each of a different virulent parent, remained moderately virulent (i.p. LD50S for BALB/c mice, ca. 10(5) and 5 X 10(4) CFU, respectively). Tested as live vaccines i.p., the aro strains were ineffective in salmonella-susceptible BALB/c and C57BL/6 mice but were somewhat effective in salmonella-resistant CBA/J mice and in outbred CD-1 mice. The pur and thy strains were effective as live vaccines in BALB/c mice when given in sublethal doses. Two previously isolated nonvirulent galE derivatives of S. choleraesuis (i.p. LD50 in BALB/c mice, greater than 10(6) CFU) were also ineffective as live vaccines in BALB/c and C57BL/6 mice. The main antigenic difference between S. choleraesuis (O-6,7) and S. typhimurium (O-4,12) is in O-antigen character, thought to largely determine the specificity of protection in salmonellosis. Paired, nearly isogenic O-6,7 and O-4,12 derivatives were constructed from an aro S. typhimurium strain of proven efficacy as a live vaccine. Used as live vaccines, the O-4,12 member protected BALB/c mice against challenge with virulent S. typhimurium, whereas the O-6,7 member did not protect against virulent S. choleraesuis. However, BALB/c mice vaccinated with the O-6,7 member and mice vaccinated with an aro S. choleraesuis strain were protected against challenge with a moderately virulent (LD50, 5 X 10(4) CFU) O-6,7 derivative of an S. typhimurium strain.
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Groisman EA, Casadaban MJ. Cloning of genes from members of the family Enterobacteriaceae with mini-Mu bacteriophage containing plasmid replicons. J Bacteriol 1987; 169:687-93. [PMID: 3542967 PMCID: PMC211834 DOI: 10.1128/jb.169.2.687-693.1987] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
An in vivo cloning system that uses derivatives of the Escherichia coli bacteriophage Mu with plasmid replicons has been extended to five different species of the family Enterobacteriaceae. Mu and these mini-Mu replicon elements were introduced into strains of E. coli, Shigella flexneri, Salmonella typhimurium, Citrobacter freundii, and Proteus mirabilis by infection, by transformation, or by conjugation with newly constructed broad-host-range plasmids containing insertions of these elements. Lysates from these cells, lysogenic for Mu and mini-Mu elements, were used to infect sensitive recipient strains of E. coli, S. typhimurium, and C. freundii. Drug-resistant transductants had mini-Mu replicon elements with inserts of different DNA sequences. All of the lysogens made could be induced to yield high phage titers, including those coming from strains that were resistant to Mu and Mu derivatives. Clones of 10 particular genes were isolated by their ability to complement specific mutations in the recipient strains, even in the presence of the E. coli K-12 restriction system. Some of the mini-Mu replicon elements used contained lac gene fusing segments and resulted in fusions of the lac operon to control regions in the cloned sequences.
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Tominaga A, Enomoto M. Magnesium-dependent plaque formation by bacteriophage P1cinC(-) on Escherichia coli C and Shigella sonnei. Virology 1986; 155:284-8. [PMID: 3535235 DOI: 10.1016/0042-6822(86)90190-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Phage P1C(-), in a state of the phage not infective to Escherichia coli K12, was able to form plaques on a wild-type strain of E. coli C and on Shigella sonnei in the presence of Mg2+. Citrobacter freundii, Enterobacter aerogenes, and a Salmonella typhimurium galE mutant were not lysed by, but were lysogenized with P1cinC(-), whereas Klebsiella pneumoniae, Proteus rettgeri, and S. typhimurium LT2 were not susceptible to either P1cinC(-) or P1cinC(+). The lipopolysaccharide structure of E. coli C and Sh. sonnei is discussed with reference to receptors for P1cinC(-) and P1cinC(+).
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Abstract
The transport of proline is important for the adaptation of Salmonella typhimurium to osmotic stress because exogenous proline permits the growth of the organism in media of elevated osmotic strength that would otherwise be toxic. Measurements of the rate of [3H]proline transport in S. typhimurium indicated that the organism has two distinct proline permeases, the ProU and the ProP systems, whose activities increase more than fivefold as a consequence of growth in media containing 0.3 M NaCl or 0.47 M sucrose. Transport via a third proline permease, the PutP system, is not affected by the osmotic strength of the medium. We constructed strains that carry fusions of lacZ to proU or proP, genes that are required for the two osmotically stimulated proline transport systems. Assays of beta-galactosidase revealed that the transcription of the proU gene is increased more than 10-fold as a result of exposure of the cells to 0.3 M NaCl, 0.47 M sucrose, or equivalent concentrations of other solutes that are not freely diffusible across the cytoplasmic membrane. Increased transcription cannot be triggered by methanol, ethanol, and glycerol, substances that are freely diffusible across the membrane, suggesting that the signal for increased transcription might be an osmotic gradient across the cytoplasmic membrane. The proP gene does not show transcriptional regulation of sufficient magnitude to account for the stimulation of [3H]proline transport. Thus, the osmotic stimulation of the ProP system might be mediated by some posttranscriptional event.
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Liljeström P, Pirhonen M, Palva ET. In vivo transfer of chromosomal mutations onto multicopy plasmids by transduction with bacteriophage P1. Gene 1985; 40:241-6. [PMID: 3913625 DOI: 10.1016/0378-1119(85)90046-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
A technique is presented by which chromosomal mutations may be efficiently transferred onto chimeric multicopy plasmids in vivo. The technique employs the transduction of plasmids using bacteriophage P1 as vector. The utility of this method was demonstrated by cloning a chromosomal ompR mutation of Escherichia coli K-12. The high-frequency transduction of the chimeric plasmid appeared to be dependent on its integration into the chromosome by homologous recombination. The results also suggest that the plasmid was transduced as part of the chromosome and resolved from its integrated state in the recipient cell, resulting in a high yield of mutant plasmid segregants.
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Abstract
A Mu d1 derivative is described which is useful for genetic manipulation of Mu-lac fusion insertions. A double mutant of the specialized transducing phage Mu d1(Amp Lac c62ts) was isolated which is conditionally defective in transposition ability. The Mu d1 derivative, designated Mu d1-8(Tpn[Am] Amp Lac c62ts), carries mutations which virtually eliminate transposition in strains lacking an amber suppressor. In such strains, the Mu d1-8 prophage behaves like a standard transposon. It can be moved from one strain of Salmonella typhimurium to another by the general transducing phage P22 with almost 100% inheritance of the donor insertion mutation. When introduced into a recipient carrying supD, supE, or supF, 89 to 94% of the Ampr transductants were transpositions of the donor Mu d1-8, from the transduced fragment into new sites. The stability of Mu d1-8 in a wild-type, suppressor-free background was sufficient to permit use of the fusion to select constitutive mutations without prior isolation of deletions to stabilize the fusion. Fusion strains could be grown at elevated temperature without induction of the Mu d prophage. The transposition defect of Mu d1-8 was corrected by a plasmid carrying the Mu A and B genes.
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Bullas LR, Ryu JI. Salmonella typhimurium LT2 strains which are r- m+ for all three chromosomally located systems of DNA restriction and modification. J Bacteriol 1983; 156:471-4. [PMID: 6352690 PMCID: PMC215113 DOI: 10.1128/jb.156.1.471-474.1983] [Citation(s) in RCA: 249] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
We describe the derivation of two strains of Salmonella typhimurium LT2 which are r- m+ for all three of the known chromosomal genes for the restriction and modification of DNA, hsdLT, hsdSA, and hsdSB; the strains were designated LB5000 and LB5010. LB5000 is a smooth derivative sensitive to phage P22; LB5010 is a galE strain sensitive to phage P1.
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Higgins CF, Hardie MM, Jamieson D, Powell LM. Genetic map of the opp (Oligopeptide permease) locus of Salmonella typhimurium. J Bacteriol 1983; 153:830-6. [PMID: 6296055 PMCID: PMC221702 DOI: 10.1128/jb.153.2.830-836.1983] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
The uptake of peptides by Salmonella typhimurium is mediated by three apparently independent transport systems. One of these systems, the oligopeptide permease, is encoded by a genetic locus (opp) which has been mapped at 34 min on the S. typhimurium chromosomal map. We accurately mapped the location of opp by cotransduction frequencies and by deletion analysis and show that the gene order for this region of the chromosome is cysB-trp-tonB-opp-galU-tdk. All opp mutants, independently isolated by a variety of means, mapped at this one locus, between tonB and galU. Spontaneous and transposon Tn10-generated deletions were used to construct a fine-structure genetic map of opp. Evidence is presented which indicates that opp covers a 5- to 6-kb segment of DNA and is therefore likely to consist of more than one gene.
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Van Gijsegem F, Toussaint A. Chromosome transfer and R-prime formation by an RP4::mini-Mu derivative in Escherichia coli, Salmonella typhimurium, Klebsiella pneumoniae, and Proteus mirabilis. Plasmid 1982; 7:30-44. [PMID: 6211681 DOI: 10.1016/0147-619x(82)90024-5] [Citation(s) in RCA: 126] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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Abstract
The role of lipopolysaccharide in regulating the expression of the ompA outer membrane protein gene of Escherichia coli K-12 was studied by isolating mutants defective in the biosynthesis of lipopolysaccharide and by examining transcription of lacZ in strains carrying operon fusions in which lacZ is expressed from the ompA promoter. By selecting for simultaneous resistance to phages K3 and U3, we obtained mutants defective in rfaC (biosynthesis of core heptose) and in rfaP (phosphorylation of core heptose), and both of these mutant strains failed to express OmpA protein in the outer membrane. Expression of lacZ from the ompA or by foreign ompA alleles which are not expressed in E. coli K-12. Expression was increased in strains carrying rfaC and rfaP mutations. No precursor or degraded form of OmpA protein accumulated in cells which could not express the protein in the outer membrane. This lack of accumulation of precursor was observed even in the presence of phenethyl alcohol, which caused accumulation of OmpA precursor in wild-type cells. We present a model for the regulation of this gene which is consistent with these observations and which involves modulation of transcription coupled to translation of the protein.
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Faelen M, Mergeay M, Gerits J, Toussaint A, Lefèbvre N. Genetic mapping of a mutation conferring sensitivity to bacteriophage Mu in Salmonella typhimurium LT2. J Bacteriol 1981; 146:914-9. [PMID: 7016837 PMCID: PMC216944 DOI: 10.1128/jb.146.3.914-919.1981] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Two strains of Salmonella typhimurium LT2, SA1475 and MA411, were fortuitously found to be sensitive to bacteriophage Mu. The Mu-sensitivity allele of SA1475 was called musA1 and shown to be linked to the histidine operon both in conjugation and transduction experiments. The Mus allele of MA411 was unlinked to the his region and was tentatively designated musB2. Strains carrying large deletions of the his operon were also tested for Mu sensitivity; those of which the his-rib region is deleted were also sensitive to Mu. Transduction data led to the order zee-2 hisOGDCBAHFIE gnd musA. An Hfr injecting the his operon early (HfrK9) an carrying hisG9424::Tn10 delta 4 delta 11 and musA1 was isolated; this Hfr made it possible to introduce the Mus character into most derivatives of S. typhimurium LT2. Since strain SA1475 is resistant to bacteriophage P1, it could be used to select a new P1-Mu hybrid which has the host range of Mu and the transduction properties of P1.
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Csonka LN, Howe MM, Ingraham JL, Pierson LS, Turnbough CL. Infection of Salmonella typhimurium with coliphage Mu d1 (Apr lac): construction of pyr::lac gene fusions. J Bacteriol 1981; 145:299-305. [PMID: 6450746 PMCID: PMC217273 DOI: 10.1128/jb.145.1.299-305.1981] [Citation(s) in RCA: 66] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
A procedure was developed for introducing the coliphage Mu d1 (Apr lac) into Salmonella typhimurium in order to construct gene fusions that place the structural genes of the lac operon under the control of the promoter-regulatory region of other genes. To introduce Mu d1 from Escherichia coli K-12 into S. typhimurium, which is normally not a host for Mu, we first constructed an E. coli double lysogen carrying the defective Mu d1 phage and a Mu-P1 hybrid helper phage (MuhP1) that confers the P1 host range. A lysate prepared from this strain was used to infect a P1-sensitive (i.e., galE), restriction-deficient, modification-proficient strain of S. typhimurium, and a double lysogen carrying Mu d1 and MuhP1 was isolated. Induction of the latter strain produced lysates capable of infecting and generating gene fusions in P1-sensitive strains of S. typhimurium. In this paper we describe the construction of pyr::lac fusions by this technique.
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Kutsukake K, Iino T, Komeda Y, Yamaguchi S. Functional homology of fla genes between Salmonella typhimurium and Escherichia coli. MOLECULAR & GENERAL GENETICS : MGG 1980; 178:59-67. [PMID: 6991880 DOI: 10.1007/bf00267213] [Citation(s) in RCA: 67] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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