the primary structure of the coat protein of pseudomonas aeruginosa rna-bacteriophage pp7 [proceedings]. 197779389
initiation of translation with pseudomonas aeruginosa phage pp7 rna: nucleotide sequence of the coat cistron ribosome binding site.initiation complex formation between pp7 rna and ribosomes of pseudomonas aeruginosa and escherichia coli has been investigated. the pp7 rna fragments protected by both species of ribosome have been isolated, and their sequences have been determined. only one binding sites is available on the intact pp7 rna strand, and this site is recognized by ribosomes of both species. the pp7 rna binding site is approximately 38 nucleotides long. it contains two aug sequences and a purine-rich segment near t ...1979109813
refined molecular weights for phage, viral and ribosomal rna.the rnas of the escherichia coli bacteriophages ms2 and qbeta as well as e. coli 16s ribosomal rna were examined under identical conditions by electron microscopy using the protein-free benzyldimethylalkylammonium chloride (bac) spreading technique. from the contour length ratios of the rnas and the known number of nucleotides for ms2, the chain lengths for qbeta rna and 16s rna were found to be 4790 +/- 150 and 1645 +/- 55 nucleotides. correcting for the base composition of qbeta rna the molecu ...1978365689
secondary structure of rna from bacteriophages f2 qbeta, and pp7.electron microscopy of rna-protein monolayers prepared under partial denaturing conditions has been used to compare the secondary structure of coliphage f2 and qbeta and pseudomonas aeruginosa phage pp7 rnas. the secondary structure map of f2 rna contains a central open loop and four symmetrically placed hairpins, which is similar to the pattern reported by jacobson (a. b. jacobson, proc. natl. acad. sci. u.s.a. 73:307-311, 1976) for the closely related phage ms2. with the same denaturing condit ...1977409852
the molecular size of the rna genome of pseudomonas aeruginosa bacteriophage pp7. 1975808034
translation of pseudomonas aeruginosa bacteriophage pp7 rna by a cell-free amino acid incorporating system from escherichia coli.we have compared the activities of the rna genomes of pseudomonas aeruginosa phage pp7 and coliphages qbeta and f2 in a cell-free amino acid incorporating system derived from escherichia coli. the rate of incorporation of [(14)c]leucine in the pp7 rna-directed system is greater than in the systems directed by either qbeta or f2 rna. the response to changes in phage rna concentrations is similar in all the systems, reaching a saturation level at 0.75 to 1.0 mg of rna per ml of reaction mixture. a ...19744208879
translation of virus mrna: synthesis of bacteriophage pp7 proteins in cell-free extracts from pseudomonas aeruginosa. 19744214374
the infection of pseudomonas aeruginosa by rna pilus phage pp7: the adsorption organelle and the relationship between phage sensitivity and the division cycle. 19714999124
complete amino acid sequence of the coat protein of the pseudomonas aeruginosa rna bacteriophage pp7. 19806772187
nucleotide sequence of a single-stranded rna phage from pseudomonas aeruginosa: kinship to coliphages and conservation of regulatory rna structures.we report the complete nucleotide sequence of the single-stranded rna phage pp7 from pseudomonas aeruginosa. there are three open reading frames which code for apparent protein homologues of the single-stranded rna coliphages, i.e., maturation protein, coat protein, and replicase. a fourth overlapping reading frame exists that probably encodes a lysis protein, similar to what has been found in the group a coliphages such as ms2. the genetic map of pp7 is colinear with group a coliphages and we a ...19957831817
the removal of phages t1 and pp7, and poliovirus from fluids with hollow-fiber ultrafilters with molecular weight cut-offs of 50,000, 13,000, and 6000.we tested the ability of hollow-fiber ultrafilters with molecular weight cut-offs (mwcos) of 50,000, 13,000, and 6000 to remove and detect viral agents (phage t1, 50-150 nm; phage pp7, poliovirus, 28-30 nm) from ultrapure water, 0.85% saline with 1% trypticase soy broth, and dulbecco's modified eagle minimum essential medium with 10% fetal bovine serum (dmem-10). virus diluted in saline and dmem-10 were tested to evaluate filter performance under conditions that minimize the adsorption of viral ...19958590412
the use of a microporous polyvinylidene fluoride (pvdf) membrane filter to separate contaminating viral particles from biologically important proteins.viral agents (influenza a virus, 80-120 nm; phage t1, 50 nm head, 150 nm head, 150 nm tail; phage pr772, 53 nm; poliovirus, 28-30 nm; and phage pp7, 25 nm) were used to determine the ability of a newly developed, modified polyvinylidene fluoride (pvdf) membrane filter to remove viruses from several fluids. these included ultrapure water, dulbecco's modified eagle minimum essential medium (dmem) and dmem with 10% fetal bovine serum (dmem-10). small volume (10 ml) filtration experiments were done ...19968889061
structure determination of bacteriophage pp7 from pseudomonas aeruginosa: from poor data to a good map.the structure of bacteriophage pp7 from pseudomomas aeruginosa was determined to 3.7 a resolution. triclinic crystals of three forms were obtained, diffracting to between 4.5 and 3.4 a resolution. the quality of the crystals was exceptionally poor, leading to problems in the evaluation of the recorded images and to a final data set which would appear to be useless with standard criteria for protein crystals. in all crystal forms, the unit cell contains two icosahedral particles, providing 120-fo ...200010739912
the three-dimensional structure of bacteriophage pp7 from pseudomonas aeruginosa at 3.7-a resolution.the three-dimensional structure of phage pp7 from pseudomonas aeruginosa has been determined to 3.7-a resolution. a comparison with distantly related small rna phages showed that the biggest differences were found in the fg loops, forming the contacts around the fivefold and threefold axes. in contrast to the situation in other phages, the fg loops of phage pp7 are very similar in all three subunits. this supports the hypothesis that no switches are needed for the assembly control in these virus ...200010873776
translational repression and specific rna binding by the coat protein of the pseudomonas phage pp7.pp7 is a single-strand rna bacteriophage of pseudomonas aeroginosa and a distant relative to coliphages like ms2 and qbeta. here we show that pp7 coat protein is a specific rna-binding protein, capable of repressing the translation of sequences fused to the translation initiation region of pp7 replicase. its rna binding activity is specific since it represses the translational operator of pp7, but does not repress the operators of the ms2 or qbeta phages. conditions for the purification of coat ...200111306589
rna recognition site of pp7 coat protein.the coat proteins of different single-strand rna phages use a common protein tertiary structural framework to recognize different rna hairpins and thus offer a natural model for understanding the molecular basis of rna-binding specificity. here we describe the rna structural requirements for binding to the coat protein of bacteriophage pp7, an rna phage of pseudomonas. its recognition specificity differs substantially from those of the coat proteins of its previously characterized relatives such ...200212364592
optimization of a reusable hollow-fiber ultrafilter for simultaneous concentration of enteric bacteria, protozoa, and viruses from water.the detection and identification of pathogens from water samples remain challenging due to variations in recovery rates and the cost of procedures. ultrafiltration offers the possibility to concentrate viral, bacterial, and protozoan organisms in a single process by using size-exclusion-based filtration. in this study, two hollow-fiber ultrafilters with 50,000-molecular-weight cutoffs were evaluated to concentrate microorganisms from 2- and 10-liter water samples. when known quantities (10(5) to ...200312839786
comparison of 2 ultrafiltration systems for the concentration of seeded viruses from environmental waters.the use of ultrafiltration as a concentration method to recover viruses from environmental waters was investigated. two ultrafiltration systems (hollow fiber and tangential flow) in a large- (100 l) and small-scale (2 l) configuration were able to recover greater than 50% of multiple viruses (bacteriophage pp7 and t1 and poliovirus type 2) from varying water turbidities (10-157 nephelometric turbidity units (ntu)) simultaneously. mean recoveries (n = 3) in ground and surface water by the large-s ...200515980891
spatial heterogeneity and the stability of host-parasite coexistence.spatially heterogeneous environments can theoretically promote more stable coexistence of hosts and parasites by reducing the risk of parasite attack either through providing permanent spatial refuges or through providing ephemeral refuges by reducing dispersal. in experimental populations of pseudomonas aeruginosa and the bacteriophage pp7, spatial heterogeneity promoted stable coexistence of host and parasite, while coexistence was significantly less stable in the homogeneous environment. phag ...200616599913
validation of hollow fiber ultrafiltration and real-time pcr using bacteriophage pp7 as surrogate for the quantification of viruses from water samples.a quantitative real-time taqman pcr system for pseudomonas aeruginosa bacteriophage pp7 was designed to detect pp7 as surrogate in performance tests of 2 hollow fiber ultrafiltration systems in series. fifty-six storm water samples from 21 sites representing agricultural, urban and highway locations in california were collected. the optimized procedure gave recoveries of spiked pp7 of 64+/-4.8% (mean+/-sem). the pp7 assay was validated over 5 orders of magnitude with an assay limit of detection ...200717313967
molecular quantitative analysis of human viruses in california stormwater.many human pathogenic viruses are transmitted via the oral-fecal route and water is one possible vector, representing a risk for public health. sixty-one large-volume water samples from storm drains in california were processed by a two-step hollow fiber ultrafiltration procedure followed by molecular analysis for human enterovirus and adenovirus types. each sample was spiked with a surrogate, the benign bacteriophage pp7. both surrogate and human viruses were quantified by newly designed taqman ...200717628629
stability and assembly in vitro of bacteriophage pp7 virus-like particles.abstract:200718039380
a consensus rating method for small virus-retentive filters. i. method development.virus filters are membrane-based devices that remove large viruses (e.g., retroviruses) and/or small viruses (e.g., parvoviruses) from products by a size exclusion mechanism. in 2002, the parenteral drug association (pda) organized the pda virus filter task force to develop a common nomenclature and a standardized test method for classifying and identifying viral-retentive filters. one goal of the task force was to develop a test method for small virus-retentive filters. because small virus-rete ...200819055228
a consensus rating method for small virus-retentive filters. ii. method evaluation.virus filters are membrane-based devices that remove large viruses (e.g., retroviruses) and/or small viruses (e.g., parvoviruses) from products by a size exclusion mechanism. in 2002, the parenteral drug association (pda) organized the pda virus filter task force to develop a common nomenclature and a standardized test method for classifying and identifying viral-retentive filters. a test method based on bacteriophage pp7 retention was chosen based on developmental studies. the detailed final co ...200819055229
combined use of ms2 and pp7 coat fusions shows that tia-1 dominates hnrnp a1 for k-sam exon splicing control.splicing of the fgfr2 k-sam exon is repressed by hnrnp a1 bound to the exon and activated by tia-1 bound to the downstream intron. both proteins are expressed similarly by cells whether they splice the exon or not, so it is important to know which one is dominant. to answer this question, we used bacteriophage pp7 and bacteriophage ms2 coat fusions to tether hnrnp a1 and tia-1 to distinct sites on the same pre-mrna molecule. hnrnp a1 fused to one coat protein was tethered to a k-sam exon contain ...201020130820
immunogenic display of diverse peptides, including a broadly cross-type neutralizing human papillomavirus l2 epitope, on virus-like particles of the rna bacteriophage pp7.the immunogenicity of an antigen can be dramatically increased by displaying it in a dense, multivalent context, such as on the surface of a virus or virus-like particle (vlp). here we describe a highly versatile vlp platform for peptide display based on vlps of the rna bacteriophage pp7. we show that this platform can be used for the engineered display of specific peptide sequences as well as for the construction of random peptide libraries. peptides representing the flag epitope, the v3 loop o ...201020434554
detection of rotavirus a in sewage samples using multiplex qpcr and an evaluation of the ultracentrifugation and adsorption-elution methods for virus a rotaviruses (rv-a) are the most common agents of viral gastroenteritis in children worldwide. the goal of this study was to compare two different methods to concentrate rv-a from sewage samples and to improve the detection and quantification of rv-a using a multiplex quantitative pcr assay with an internal control. both rv-a and the internal control virus, bacteriophage pp7, were seeded into wastewater and then concentrated using either an ultrafiltration-based adsorption-elution protoco ...201020804786
thermal stability of rna phage virus-like particles displaying foreign peptides.abstract: background: to be useful for genetic display of foreign peptides a viral coat protein must tolerate peptide insertions without major disruption of subunit folding and capsid assembly. the folding of the coat protein of rna phage ms2 does not normally tolerate insertions in its ab-loop, but an engineered single-chain dimer readily accepts them as long as they are restricted to one of its two halves. results: here we characterize the effects of peptide insertions on the thermal stabiliti ...201121609437
differential bacteriophage mortality on exposure to copper.many studies report that copper can be used to control microbial growth, including that of viruses. we determined the rates of copper-mediated inactivation for a wide range of bacteriophages. we used two methods to test the effect of copper on bacteriophage survival. one method involved placing small volumes of bacteriophage lysate on copper and stainless steel coupons. following exposure, metal coupons were rinsed with lysogeny broth and the resulting fluid was serially diluted and plated on ag ...201121841029
A pan-HPV vaccine based on bacteriophage PP7 VLPs displaying broadly cross-neutralizing epitopes from the HPV minor capsid protein, L2.Current human papillomavirus (HPV) vaccines that are based on virus-like particles (VLPs) of the major capsid protein L1 largely elicit HPV type-specific antibody responses. In contrast, immunization with the HPV minor capsid protein L2 elicits antibodies that are broadly cross-neutralizing, suggesting that a vaccine targeting L2 could provide more comprehensive protection against infection by diverse HPV types. However, L2-based immunogens typically elicit much lower neutralizing antibody titer ...201121858066
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