Flagellar determinants of bacterial sensitivity to chi-phage.
17 Aug 1999-Proceedings of the National Academy of Sciences of the United States of America (National Academy of Sciences)-Vol. 96, Iss: 17, pp 9863-9866
TL;DR: Evidence is provided for a "nut and bolt" model for translocation of phage along the filament: the tail fiber of chi fits the grooves formed by helical rows of flagellin monomers, and activeFlagellar rotation forces the phage to follow the groove as a nut follows the threads of a bolt.
Abstract: Bacteriophage χ is known to infect motile strains of enteric bacteria by adsorbing randomly along the length of a flagellar filament and then injecting its DNA into the bacterial cell at the filament base. Here, we provide evidence for a “nut and bolt” model for translocation of phage along the filament: the tail fiber of χ fits the grooves formed by helical rows of flagellin monomers, and active flagellar rotation forces the phage to follow the grooves as a nut follows the threads of a bolt.
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TL;DR: A powerful experimental framework is developed that combines competitive selection and microarray-based genetic footprinting to comprehensively reveal the genetic basis of bacterial behaviors and uncovers genome-wide epistatic interactions through comprehensive analyses of double-mutant phenotypes.
Abstract: We have developed a powerful experimental framework that combines competitive selection and microarray-based genetic footprinting to comprehensively reveal the genetic basis of bacterial behaviors. Application of this method to Escherichia coli motility identifies 95% of the known flagellar and chemotaxis genes, and reveals three dozen novel loci that, to varying degrees and through diverse mechanisms, affect motility. To probe the network context in which these genes function, we developed a method that uncovers genome-wide epistatic interactions through comprehensive analyses of double-mutant phenotypes. This allows us to place the novel genes within the context of signaling and regulatory networks, including the Rcs phosphorelay pathway and the cyclic di-GMP second-messenger system. This unifying framework enables sensitive and comprehensive genetic characterization of complex behaviors across the microbial biosphere.
216 citations
Cites background or methods from "Flagellar determinants of bacterial..."
...Infectivity with bacteriophage v was assayed as described previously with minor modifications [25]....
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...CCW flagellar rotation and the correct pattern of grooves on the surface of the flagellum are thought to drive v-phage down the filament to the surface of the membrane, very similar to how a nut follows the grooves of a rotating bolt [25]....
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TL;DR: All mechanisms of bacterial manipulation of the host organisms can be viewed in three principal categories: microbial adhesion, secretion of toxins into the extracellular milieu, and injection of virulence factors into host cells.
Abstract: The skin, the oral cavity, and the gastrointestinal tract of humans are colonized with bacteria. Microbial entry into the blood or blood-circulated tissues is hindered by anatomical barriers. The barriers consist of epithelia as well as membranes that are fortified by layers of collagen and other connective tissues. Following the breakdown of a barrier, the dwindling of an immune system, or an attack by particularly virulent bacteria, microbes gain entry into deeper tissues and multiply within newly conquered space. Human disease is the result of such bacterial multiplication. Microbial entry into circulated tissue is accompanied by an immune response. Immune cells recognize bacterial products (lipids, carbohydrates, peptidoglycan, or protein decorations) and respond by attracting macrophages, polymorph-nuclear leukocytes, or other immune cells in an effort to kill the invading pathogen (Medzhitov and Janeway 1999; Aderem and Ulevitch 2000). Many bacterial pathogens have evolved to enter and multiply within blood-circulated tissues (Finlay and Falkow 1997). The underlying pathogenic strategies are remarkably diverse and often result in unique disease symptoms. Nevertheless, all mechanisms of bacterial manipulation of the host organisms can be viewed in three principal categories: microbial adhesion, secretion of toxins into the extracellular milieu, and injection of virulence factors into host cells. There are three rules of thumb that bacterial pathogens must consider if they want to mount a successful infection.
216 citations
Cites background from "Flagellar determinants of bacterial..."
...1982), bound bacteriophage seems to spiral down the filament towards the bacterial surface propelled by its counter-clockwise rotation, much like a nut rotates on a screw (Berg and Anderson 1973; Samuel et al. 1999)....
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...1967), a mechanism that also requires flagellar rotation (Berg and Anderson 1973; Samuel et al. 1999)....
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...…a right-handed helical ridge (O’Brien and Bennett 1972; Wagenknecht et al. 1982), bound bacteriophage seems to spiral down the filament towards the bacterial surface propelled by its counter-clockwise rotation, much like a nut rotates on a screw (Berg and Anderson 1973; Samuel et al. 1999)....
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...Adhesion of bacteriophage % to the flagellar filament provides for its transport to the bacterial surface (Schade et al. 1967), a mechanism that also requires flagellar rotation (Berg and Anderson 1973; Samuel et al. 1999)....
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TL;DR: The short- and long-term costs and benefits of the different resistance strategies and, hence, the ecological conditions that are likely to favor the different strategies alone and in combination are discussed.
Abstract: Bacteria have a range of distinct immune strategies that provide protection against bacteriophage (phage) infections. While much has been learned about the mechanism of action of these defense strategies, it is less clear why such diversity in defense strategies has evolved. In this review, we discuss the short- and long-term costs and benefits of the different resistance strategies and, hence, the ecological conditions that are likely to favor the different strategies alone and in combination. Finally, we discuss some of the broader consequences, beyond resistance to phage and other genetic elements, resulting from the operation of different immune strategies.
195 citations
Cites background from "Flagellar determinants of bacterial..."
...Receptor loss is commonly seen under laboratory conditions, especially when phages use motility organelles, such as the flagellum or the pilus, to enter the host cell (4, 5) or receptors that are not essential under laboratory conditions, such as the LamB receptor, which is necessary for maltose uptake and hence is dispensable when bacteria are grown in LB medium (6)....
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TL;DR: This is the first report identifying specific infection and inhibition of Salmonella Typhimurium and E. coli O157:H7 by a single bacteriophage, implying that the genes are major host specificity determinants.
Abstract: Salmonella enterica and Escherichia coli O157:H7 are major food-borne pathogens causing serious illness. Phage SFP10, which revealed effective infection of both S. enterica and E. coli O157:H7, was isolated and characterized. SFP10 contains a 158-kb double-stranded DNA genome belonging to the Vi01 phage-like family Myoviridae. In vitro adsorption assays showed that the adsorption constant rates to both Salmonella enterica serovar Typhimurium and E. coli O157:H7 were 2.50 × 10−8 ml/min and 1.91 × 10−8 ml/min, respectively. One-step growth analysis revealed that SFP10 has a shorter latent period (25 min) and a larger burst size (>200 PFU) than ordinary Myoviridae phages, suggesting effective host infection and lytic activity. However, differential development of resistance to SFP10 in S. Typhimurium and E. coli O157:H7 was observed; bacteriophage-insensitive mutant (BIM) frequencies of 1.19 × 10−2 CFU/ml for S. Typhimurium and 4.58 × 10−5 CFU/ml for E. coli O157:H7 were found, indicating that SFP10 should be active and stable for control of E. coli O157:H7 with minimal emergence of SFP10-resistant pathogens but may not be for S. Typhimurium. Specific mutation of rfaL in S. Typhimurium and E. coli O157:H7 revealed the O antigen as an SFP10 receptor for both bacteria. Genome sequence analysis of SFP10 and its comparative analysis with homologous Salmonella Vi01 and Shigella phiSboM-AG3 phages revealed that their tail fiber and tail spike genes share low sequence identity, implying that the genes are major host specificity determinants. This is the first report identifying specific infection and inhibition of Salmonella Typhimurium and E. coli O157:H7 by a single bacteriophage.
138 citations
Cites methods from "Flagellar determinants of bacterial..."
...Various components of the bacterial outermost cell layer, such as flagella (61, 63), O antigen of LPS (4, 39, 47), OmpC (28, 67, 72), and BtuB (29, 35), are used as bacteriophage receptors....
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TL;DR: This review examines bacteria and phage distributions in nature first by highlighting biogeographic patterns and nonhost environmental influences on phage distribution, then by considering the ways in which phages and bacteria interact, emphasizing phage life cycles, bacterial responses to phage infection, and the complex patterns of phage host specificity.
Abstract: Phages are considered the most abundant and diverse biological entities on Earth and are notable not only for their sheer abundance, but also for their influence on bacterial hosts. In nature, bacteria-phage relationships are complex and have far-reaching consequences beyond particular pairwise interactions, influencing everything from bacterial virulence to eukaryotic fitness to the carbon cycle. In this review, we examine bacteria and phage distributions in nature first by highlighting biogeographic patterns and nonhost environmental influences on phage distribution, then by considering the ways in which phages and bacteria interact, emphasizing phage life cycles, bacterial responses to phage infection, and the complex patterns of phage host specificity. Finally, we discuss phage impacts on bacterial abundance, genetics, and physiology, and further aim to clarify distinctions between current theoretical models and point out areas in need of future research.
133 citations
Cites background from "Flagellar determinants of bacterial..."
...Adsorption requires that phages recognize bacterial receptors on the cell surface, including lipopolysaccharides, flagella, or pili (Lindberg, 1973; Mattick, 2002; Samuel et al., 1999)....
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...bacterial receptors on the cell surface, including lipopolysaccharides, flagella, or pili (Lindberg, 1973; Mattick, 2002; Samuel et al., 1999)....
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References
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TL;DR: It is shown here that existing evidence favours a model in which each filament rotates, which is commonly believed that each filament propagates a helical wave3.
Abstract: IT is widely agreed that bacteria swim by moving their flagella, but how this motion is generated remains obscure1,2. A flagellum has a helical filament, a proximal hook, and components at its base associated with the cell wall and the cytoplasmic membrane. If there are several flagella per cell, the filaments tend to form bundles and to move in unison. When viewed by high-speed cinematography, the bundles show a screw-like motion. It is commonly believed that each filament propagates a helical wave3. We will show here that existing evidence favours a model in which each filament rotates.
877 citations
TL;DR: A method for generating gene replacements and deletions in Escherichia coli using a temperature-sensitive pSC101 replicon to facilitate the gene replacement and can be used to generate deletions of essential genes.
Abstract: We describe a method for generating gene replacements and deletions in Escherichia coli. The technique is simple and rapid and can be applied to most genes, even those that are essential. What makes this method unique and particularly effective is the use of a temperature-sensitive pSC101 replicon to facilitate the gene replacement. The method proceeds by homologous recombination between a gene on the chromosome and homologous sequences carried on a plasmid temperature sensitive for DNA replication. Thus, after transformation of the plasmid into an appropriate host, it is possible to select for integration of the plasmid into the chromosome at 44 degrees C. Subsequent growth of these cointegrates at 30 degrees C leads to a second recombination event, resulting in their resolution. Depending on where the second recombination event takes place, the chromosome will either have undergone a gene replacement or retain the original copy of the gene. The procedure can also be used to effect the transfer of an allele from a plasmid to the chromosome or to rescue a chromosomal allele onto a plasmid. Since the resolved plasmid can be maintained by selection, this technique can be used to generate deletions of essential genes.
740 citations
TL;DR: Motile, but generally nonchemotactic mutants of Escherichia coli were examined for complementation and recombination with specialized lambdafla transducing phages, finding mutants defective in cheA, cheW, cheX, or cheY function swam smoothly, whereas cheB or cheZ mutants exhibited very high tumbling rates.
Abstract: Motile, but generally nonchemotactic (che) mutants of Escherichia coli were examined for complementation and recombination with specialized lambdafla transducing phages. The complex complementation behavior of these mutants found previously in F-prime tests could largely be accounted for by intragenic complementation and by polarity effects. Mutants of the "cheA" class defined two genes, cheA and cheW, which appeared to be contranscribed. Mutants of the "cheB" class defined four genes, cheX, cheB, cheY, and cheZ, which also constituted a transcriptional unit. Mutants defective in cheA, cheW, cheX, or cheY function swam smoothly, with little or no tumbling, whereas cheB or cheZ mutants exhibited very high tumbling rates. These functions are probably involved in initiating of controlling changes in flagellar rotation in response to chemotactic stimuli.
325 citations
TL;DR: Paralyzed motors of motA and motB point and deletion mutants of Escherichia coli were repaired by synthesis of wild-type protein and torque was restored in a series of equally spaced steps, suggesting the maximum complement of torque generators is eight.
Abstract: Paralyzed motors of motA and motB point and deletion mutants of Escherichia coli were repaired by synthesis of wild-type protein. As found earlier with a point mutant of motB, torque was restored in a series of equally spaced steps. The size of the steps was the same for both MotA and MotB. Motors with one torque generator spent more time spinning counterclockwise than did motors with two or more generators. In deletion mutants, stepwise decreases in torque, rare in point mutants, were common. Several cells stopped accelerating after eight steps, suggesting that the maximum complement of torque generators is eight. Each generator appears to contain both MotA and MotB.
263 citations
TL;DR: 40 mutants of Escherichia coli which are nonchemotactic as judged by their failure to swarm on semisolidtryptone plates or to make bands in capillary tubes containing tryptone broth are isolated.
Abstract: We have isolated 40 mutants of Escherichia coli which are nonchemotactic as judged by their failure to swarm on semisolid tryptone plates or to make bands in capillary tubes containing tryptone broth. All the mutants have normal flagella, a fact shown by their shape and reaction with antiflagella serum. All are fully motile under the microscope and all are sensitive to the phage chi. Unlike its parent, one of the mutants, studied in greater detail, failed to show chemotaxis toward oxygen, glucose, serine, threonine, or aspartic acid. The failure to exhibit chemotaxis does not result from a failure to use the chemicals. The swimming of this mutant was shown to be random. The growth rate was normal under several conditions, and the growth requirements were unchanged. Images
235 citations