Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
|---|
| transposition of tn4551 in bacteroides fragilis: identification and properties of a new transposon from bacteroides spp. | tn4551, a clindamycin resistance (ccr) transposon from the r plasmid pbi136, was cloned onto an escherichia coli-bacteroides shuttle vector which could replicate normally in e. coli but was maintained unstably in bacteroides fragilis. to aid in cloning and to ensure maintenance of tn4551 in e. coli, a kanamycin resistance determinant (kmr) was inserted in the transposon. the transposon-bearing shuttle vector pfd197 was transformed into b. fragilis 638, and putative insertions of tn4551::kmr were ... | 1987 | 3038840 |
| multiple repressor binding sites in the genome of bacteriophage p1. | after digestion of bacteriophage p1 dna with ecori in the presence of p1 repressor, 6 repressor binding sites were identified in 5 of 26 ecori fragments. binding sites were localized by the decreased mobility of dna fragment-repressor complexes during electrophoresis and by dnase protection ("footprinting") analysis. the repressor binding sites, or operators, comprise a 17-base-pair-long consensus sequence lacking symmetrical elements. three operators can be related to known genes, whereas the f ... | 1987 | 3039493 |
| localization of stx, a determinant essential for high-level production of shiga toxin by shigella dysenteriae serotype 1, near pyrf and generation of stx transposon mutants. | hfr strains of shigella dysenteriae serotype 1 were constructed by transient integration of an rp4 plasmid derivative carrying transposon tn501 into the shigella chromosome through tn501-mediated cointegration. the hfr strains were mated with escherichia coli k-12 recipients carrying various auxotrophic markers, and e. coli recombinants which had received prototrophic shigella genes were selected. some of the e. coli transconjugants produced high levels of a cytotoxin which was neutralized by bo ... | 1987 | 3040592 |
| transduction of escherichia coli in soil. | bacteriophage p1-mediated generalized transduction of escherichia coli k-12 was assessed in nonsterile soil. auxotrophic recipient cells (thr- leu- thi- rpsl) were incubated in a sandy and a silty clay loam soil, and the transducing phage lysates from prototrophic strains carrying transposon 10(tn10) in either pure or arol regions were added. at intervals, the bacterial populations derived from the soils were plated on selective-differential media to enumerate prototrophic (thr+, leu+, or tcr) t ... | 1988 | 3042116 |
| transduction of escherichia coli by bacteriophage p1 in soil. | transduction of escherichia coli w3110(r702) and j53(rp4) (10(4) to 10(5) cfu/g of soil) by lysates of temperature-sensitive specialized transducing derivatives of bacteriophage p1 (10(4) to 10(5) pfu/g of soil) (p1 cm cts, containing the resistance gene for chloramphenicol, or p1 cm cts::tn501, containing the resistance genes for chloramphenicol and mercury [hg]) occurred in soil amended with montmorillonite or kaolinite and adjusted to a -33-kpa water tension. in nonsterile soil, survival of i ... | 1988 | 3046491 |
| d-arabinose metabolism in escherichia coli b: induction and cotransductional mapping of the l-fucose-d-arabinose pathway enzymes. | d-arabinose is degraded by escherichia coli b via some of the l-fucose pathway enzymes and a d-ribulokinase which is distinct from the l-fuculokinase of the l-fucose pathway. we found that l-fucose and d-arabinose acted as the apparent inducers of the enzymes needed for their degradation. these enzymes, including d-ribulokinase, appeared to be coordinately regulated, and mutants which constitutively synthesized the l-fucose enzymes also constitutively synthesized d-ribulokinase. in contrast to d ... | 1988 | 3056899 |
| the cyclization of linear dna in escherichia coli by site-specific recombination. | the efficiency with which linearized plasmid dna can transform competent escherichia coli can be significantly increased by use of the cre-lox site-specific recombination system of phage p1. linear plasmid molecules containing directly repeated loxp sites (lox2 plasmids) are cyclized in cre+ e. coli strains after introduction either by transformation or by mini-mu transduction. exonuclease v activity of the recbc enzyme inhibits efficient cyclization of linearized lox2 plasmids after transformat ... | 1988 | 3063605 |
| packaging of transducing dna by bacteriophage p1. | p1 transduces bacterial chromosomal markers with widely differing frequencies. we use quantitative southern hybridisations here to show that, despite this, most markers are packaged at similar levels. exceptions are a group of markers near 2 min and another at 90 min which seem to be packaged at levels two- to threefold higher. we thus conclude that certain marker frequency variations in transduction can be explained by differences in packaging level, but that most cannot. the limited range in p ... | 1988 | 3063949 |
| genetic analysis of myxococcus xanthus and isolation of gene replacements after transduction under conditions of limited homology. | genetic analysis of myxococcus xanthus is greatly facilitated by the ability to introduce cloned dna into m. xanthus to generate gene replacement and merodiploid strains. however, gene replacement strains are difficult to obtain when the region(s) of homology between the cloned dna and the m. xanthus chromosome is limited (less than 1 kilobase). we found that gene replacements can be obtained at an increased frequency by a two-step procedure involving the use of bacteriophage p1 to isolate merod ... | 1986 | 3090023 |
| sequence and deletion analysis of the recombination enhancement gene (ref) of bacteriophage p1: evidence for promoter-operator and attenuator-antiterminator control. | the ref gene of bacteriophage p1 stimulates recombination between two defective lacz genes in the escherichia coli chromosome (lac x lac recombination) and certain other reca-dependent recombination processes. we determined the dna sequence of the 5' portion of the ref gene and tested various regions for functionality by inserting dna fragments lacking increasing amounts of 5' sequence into plasmid and lambda phage vectors and measuring the ability of the constructs to stimulate lac x lac recomb ... | 1988 | 3170487 |
| characterization of the phage p1 dam gene. | 1988 | 3248723 | |
| processing of the bacteriophage p1 packaging site (pac) is regulated by adenine methylation. | 1988 | 3248724 | |
| properties of a mutant cre protein that alters the topological linkage of recombination products. | the bacteriophage p1 cre-loxp site-specific recombination system consists of two components: the cre recombinase protein and the loxp dna sequence where recombination takes place. we report here on the analysis of a mutation in the cre structural gene that produces a mutant protein with altered recombination properties. the mutant protein, cre111, carries out recombination at a much slower rate than the wild-type cre protein. to determine why the reaction is slow, we have examined a number of ac ... | 1988 | 3262765 |
| recognition and cleavage of the bacteriophage p1 packaging site (pac). i. differential processing of the cleaved ends in vivo. | the packaging of bacteriophage p1 dna into viral capsids is initiated at a specific dna site called pac. during packaging, that site is cleaved and at least one of the resulting ends is encapsidated into a p1 virion. we show here that pac is located on a 620 base-pair fragment of p1 dna (ecori-20). when that fragment is inserted into the chromosome of cells that are then infected with p1, packaging of host dna into phage particles is initiated at pac and proceeds down the chromosome, unidirectio ... | 1987 | 3305962 |
| role of the central dinucleotide at the crossover sites for the selection of quasi sites in dna inversion mediated by the site-specific cin recombinase of phage p1. | the crossover sites for cin-mediated inversion consist of imperfect 12 bp inverted repeats with non-palindromic dinucleotides at the center of symmetry. inversion is believed to occur in vivo between the homologous central 2 bp crossover sequences at the inversely repeated crossover sites through introduction of 2 bp staggered cuts and subsequent reciprocal strand exchanges. the site-specific cin recombinase acts not only on the normal crossover sites but also, less efficiently, on quasi crossov ... | 1987 | 3312949 |
| visualization of rna polymerase bound to r-loop molecules improves electron microscopic analysis of in vitro transcription. | an electron microscope method is described which allows improved analysis of in vitro transcription. transcription complexes are fixed with glutaraldehyde, subjected to r-loop conditions which allow the nascent rna chains to hybridize to the dna templates, and mounted for electron microscopy by a protein-free preparation method. an rna polymerase molecule (or parts of it) associated with only one end of the r-loop identifies the polarity of the transcript, thus determining the origin and directi ... | 1986 | 3316423 |
| purification and dna-binding properties of fis and cin, two proteins required for the bacteriophage p1 site-specific recombination system, cin. | an escherichia coli chromosomally coded factor termed fis (factor for inversion stimulation) stimulates the cin protein-mediated, site-specific dna inversion system of bacteriophage p1 more than 500-fold. we have purified fis and the recombinase cin, and studied the inversion reaction in vitro. dna footprinting studies with dnase i showed that cin specifically binds to the recombination site, called cix. fis does not bind to cix sites but does bind to a recombinational enhancer sequence that is ... | 1987 | 3323534 |
| transductional analysis of chromosome replication time. | following transduction of exponentially growing cultures of escherichia coli with phage p1, cells with recombinant phenotype begin to increase in number after an initial lag of about one generation time. we show that transductants for markers located at different positions on the chromosome begin to increase at different times, in reverse order to that in which they are replicated. the period over which this happens is equal in duration to the time taken to replicate the chromosome and we have u ... | 1987 | 3325777 |
| characterization of the binding sites of c1 repressor of bacteriophage p1. evidence for multiple asymmetric sites. | the repressor of bacteriophage p1, encoded by the c1 gene, is responsible for maintaining a p1 prophage in the lysogenic state. in this paper we present: (1) the sequence of the rightmost 943 base-pairs of the p1 genetic map that includes the 5'-terminal 224 base-pairs of the c1 gene plus its upstream region; (2) the construction of a plasmid that directs the production of approximately 5% of the cell's protein as p1 repressor; (3) a deletion analysis that establishes the startpoint of p1 repres ... | 1987 | 3430609 |
| the role of the loxp spacer region in p1 site-specific recombination. | the lox-cre site-specific recombination system of bacteriophage p1 is comprised of a site on the dna where recombination occurs called loxp, and a protein, cre, which mediates the reaction. the loxp site is 34 base pairs (bp) in length and consists of two 13 bp inverted repeats separated by an 8 bp spacer region. previously it has been shown that the cleavage and strand exchange of recombining loxp sites occurs within this spacer region. we report here an analysis of various base substitution mu ... | 1986 | 3457367 |
| bacteriophage p1 cre gene and its regulatory region. evidence for multiple promoters and for regulation by dna methylation. | the bacteriophage p1 site-specific recombination system consists of two components, a site, loxp, at which recombination occurs, and a recombinase protein, cre. in this paper, we present the dna sequence of the cre structural gene and its upstream regulatory region. analysis of the sequence indicates: (1) that cre encodes a protein of 343 amino acids; (2) that cre and loxp are separated by a 434 base-pair region that contains a 73 amino acid open reading frame, orf1; and (3) that cre and orf1 ar ... | 1986 | 3486297 |
| localized conversion at the crossover sequences in the site-specific dna inversion system of bacteriophage p1. | the crossover sites for site-specific c inversion consist of imperfect 12 bp inverted repeats with the dinucleotide tt at the center of symmetry. the phage p1 cin recombinase acts not only at these cix sites but also less efficiently at cix-related sequences called quasi-cix sites, cixq. when cixq contains a central dinucleotide tt, crossover occurs in vivo at the 2 bp sequence tt in the normal and the quasi-cix sites. if cixq carries only one t residue, inversion-associated localized conversion ... | 1986 | 3513965 |
| genetic suppression of a temperature-sensitive groes mutation by an altered subunit of rna polymerase of escherichia coli k-12. | temperature-resistant suppressor mutants were isolated from escherichia coli mutant strain groes131(ts). phage p1-mediated transduction and a two-dimensional gel electrophoretic analysis of cellular proteins indicated that these suppressor mutants carry an additional mutation in either the groel gene or the rpoa gene. | 1987 | 3546264 |
| recognition and cleavage of the bacteriophage p1 packaging site (pac). ii. functional limits of pac and location of pac cleavage termini. | bacteriophage p1 initiates the processive packaging of its dna at a unique site called pac. we show that a functional pac site is contained within a 161 base-pair segment of p1 ecori fragment 20. it extends from a position 71 base-pairs to a position 232 base-pairs from the ecori-22 proximal side of that fragment. the 3' and 5' pac termini are located centrally within that 161 base-pair region and are distributed over about a turn of the dna helix. the dna sequence of the terminus region is show ... | 1987 | 3625770 |
| a mutational analysis of the bacteriophage p1 recombinase cre. | bacteriophage p1 encodes a 38,600 mr site-specific recombinase, cre, that is responsible for reciprocal recombination between sites on the p1 dna called loxp. using in vitro mutagenesis 67 cre mutants representing a total of 37 unique changes have been characterized. the mutations result in a wide variety of phenotypes as judged by the varying ability of each mutant cre protein to excise a lacz gene located between two loxp sites in vivo. although the mutations are found throughout the entire cr ... | 1987 | 3656435 |
| the ban operon of bacteriophage p1. localization of the promoter controlled by p1 repressor. | repression of a strong promoter localized 5' to the p1 ban gene is a prerequisite for cloning the ban operon in the multicopy plasmid pbr325. repression is brought about by the binding of p1 repressor to the operator of the ban operon (heisig, a., severin, i., seefluth, a. k., and schuster, h. (1987) mol. gen. genet. 206, 368-376). binding of rna polymerase in vitro overlaps with the operator and is inhibited by p1 repressor as shown by electron microscopy. the mutant p1 bac, which renders ban e ... | 1987 | 3680265 |
| sequence relations among the incy plasmid p15b, p1, and p7 prophages. | electron microscopic analysis of heteroduplex molecules between the 94-kb plasmid p15b and the 92-kb phage p1 genome revealed nine regions of nonhomology, eight substitutions, and two neighboring insertions. overall, the homologous segments correspond to 83% of the p1 genome and 81% of p15b. heteroduplex molecules between p15b and the 99-kb phage p7 genome showed nonhomology in eight of the same nine regions; in addition, two new nonhomologous segments are present and p7 carries a 5-kb insertion ... | 1986 | 3749335 |
| the c4 gene of phage p1. | the c4 gene of phage p1 has been localized to 335 bp of the p1ecori-9 fragment, within 50 bp of the ecori-9/14 junction. dna sequence analysis of this fragment reveals a single open reading frame of 66 amino acids. the location of two c4 mutations, both of which produce changes in the predicted amino acid sequence in this reading frame, suggests that the reading frame codes for the c4 repressor. a region with high homology to the e. coli promoter consensus sequence is located approximately 50 bp ... | 1987 | 3811234 |
| interaction of the p1c1 repressor with p1 dna: localization of repressor binding sites near the c1 gene. | the c1 repressor of phage p1 was previously shown (b.r. baumstark and j.r. scott, 1980, j. mol. biol. 140, 471-480) to bind specifically to p1bamhi-9, a 1.4-kb fragment that is closely linked to the c1 structural gene and spans the ends of the p1 genetic map. the position of the repressor binding site(s) relative to the ends of the genetic map and the c1 gene was investigated by testing cloned fragments of ecori-7 and bamhi-9 for c1 expression and repressor binding. although sequences in both ba ... | 1987 | 3811241 |
| linking-number changes in the dna substrate during cre-mediated loxp site-specific recombination. | we have examined the linking-number changes that occur during phage p1 cre-mediated recombination in vitro between two loxp sites. such recombination reactions can be divided into three types: intramolecular inversion, in which recombination occurs between two loxp sites in opposite orientations on the same dna substrate; intramolecular excision, where recombination occurs between two loxp sites that are in the same orientation on the dna substrate; and intermolecular recombination, which occurs ... | 1986 | 3820304 |
| mechanism of strand cleavage and exchange in the cre-lox site-specific recombination system. | the bacteriophage p1 recombinase cre mediates site-specific recombination between loxp sites. the loxp site consists of two 13 base-pair inverted repeats separated by an eight base-pair spacer region. when dna containing the loxp site is incubated with cre, specific cleavages occur within the spacer region, creating a six base-pair staggered cut. the cuts are centered on the axis of dyad symmetry of the loxp site, resulting in a 5' protruding terminus: 5' a decreases t-g-t-a-t-g c 3' t a-c-a-t-a ... | 1985 | 3856690 |
| p1 plasmid replication: multiple functions of repa protein at the origin. | replication functions of a bacteriophage p1 miniplasmid are carried on a 1.2-kilobase pair (kb) segment that can be subdivided into a 245-base pair (bp) replication origin and a 959-bp region that encodes a protein required for replication (repa). the origin region contains five 19-bp direct repeats. by using primer extension and gene-fusion assays, we mapped the promoter of the repa gene within the repeated sequences and showed that the promoter is repressed by repa. regulation of repa synthesi ... | 1985 | 3857601 |
| phage p1 cre-loxp site-specific recombination. effects of dna supercoiling on catenation and knotting of recombinant products. | bacteriophage p1 contains a site-specific recombination system consisting of a site, loxp, and a recombinase protein cre. we have shown that with purified cre protein we can carry out recombination between two loxp sites in vitro. when that recombination occurs between two sites in direct orientation on the same dna molecule, we observed the production of free and catenated circular molecules. in this paper we show that recombination between sites in opposite orientation leads to both knotted an ... | 1985 | 3875731 |
| genetic mapping of nth, a gene affecting endonuclease iii (thymine glycol-dna glycosylase) in escherichia coli k-12. | the nth gene of escherichia coli affects the production of endonuclease iii, a glycosylase-endonuclease that attacks dna damaged by oxidizing agents or by ionizing radiation. an nth insertion mutant and a deletion mutant were studied. nth is located between add and tyrs on the linkage map of e. coli k-12 and was 97% linked to tyrs in a transduction with phage p1. | 1985 | 3886628 |
| expression of the bacteriophage p1 cin recombinase gene from its own and heterologous promoters. | the cin recombinase of bacteriophage p1, a protein that catalyses site-specific dna inversions, has been identified and its structural gene has been cloned under the control of different promoters. one of the dna sequences used for the site-specific recombination, cixl, overlaps with the 3' end of the gene, but we show that the presence of this site does not affect cin gene expression from strong promoters. to assay cin activity we have constructed plasmids that carry antibiotic resistance genes ... | 1985 | 3891516 |
| genetic location of genes encoding enterobacterial common antigen. | a new rff mutation (rff-726) of escherichia coli is described which affects the biosynthesis of the enterobacterial common antigen. this mutation was detected in an rfe-defective strain. a tn10 insertion near the rfe locus was isolated to facilitate further mapping. both mutations rfe and rff were mapped by transduction with bacteriophage p1, giving the gene order ilv rfe rff uvrd mete. the f' factor f14 was able to complement both mutations rfe and rff, whereas the f' factor f16 could complemen ... | 1985 | 3894334 |
| in vivo transfer of chromosomal mutations onto multicopy plasmids by transduction with bacteriophage p1. | 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 tha ... | 1985 | 3913625 |
| internal promoter in the ilvgeda transcription unit of escherichia coli k-12. | segments of the ilvgeda transcription unit have been cloned into the promoter tester plasmid pmc81. this vector contains cloning sites situated upstream of the lacz gene coding for beta-galactosidase. using this method we have quantitatively evaluated in vivo (i) the activity of previously described promoter, pg, preceding ilvg; (ii) the relative activity of pe promoter, previously postulated to be located between ilvg and ilve; and (iii) the effect of the frameshift site present in the wild-typ ... | 1985 | 3917997 |
| transduction of r factors with phage p1 from recombination-deficient escherichia coli. | 1970 | 4097418 | |
| nucleotide sequences at the sites of action of the deoxyribonucleic acid modification enzyme of bacteriophage p1. | 1974 | 4453003 | |
| a new gene controlling lysogeny in phage p1. | 1972 | 4552789 | |
| lysogenic conversion of pasteurella by escherichia coli bacteriophage p1 cm. | bacteriophage p1 cm can convert pasteurella pestis or p. pseudotuberculosis to chloramphenicol resistance and phage restriction, but no viable phage was induced from converted pasteurella strains. | 1972 | 4553681 |
| formation, induction, and curing of bacteriophage p1 lysogens. | 1972 | 4555608 | |
| the addition of lac+ chromosome fragments to the e. coli proa-prob-lac deletion 13 chromosome. | escherichia coli with the proa-prob-lac deletion x111 (delta111) can be transduced with bacteriophage p1 propagated on a wild-type lac(+) donor. though the donor lac(+) genes cannot be integrated by replacement of the recipient delta111 marker, the transduction process has the characteristics generally associated with generalized transduction of bacterial genes. transduction does not require p1 helper infection, is stimulated by uv irradiation of transducing particles, and does require homology ... | 1972 | 4556177 |
| expression of the escherichia coli k, b and phage p1 dna host specificities in salmonella typhimurium. | 1972 | 4557386 | |
| factors affecting virulence of shigella flexneri: defective methionine synthesis in an escherichia coli-shigella hybrid. | an escherichia coli-shigella flexneri hybrid of intermediate virulence was studied to determine whether its shorter survival in host cells might be due to a metabolic defect. investigation of its growth in minimal glucose medium showed that the hybrid, like its e. coli parent, had a longer lag phase and a slower growth rate than its virulent shigella parent. methionine was found to increase the growth rate of the hybrid. the shigella parent of the hybrid can synthesize methionine normally, but t ... | 1972 | 4562393 |
| methylation of bacteriophage p1 dna. | 1972 | 4563041 | |
| isolation and properties of fumarate reductase mutants of escherichia coli. | escherichia coli produces two enzymes which interconvert succinate and fumarate: succinate dehydrogenase, which is adapted to an oxidative role in the tricarboxylic acid cycle, and fumarate reductase, which catalyzes the reductive reaction more effectively and allows fumarate to function as an electron acceptor in anaerobic growth. a glycerol plus fumarate medium was devised for the selection of mutants (frd) lacking a functional fumarate reductase by virtue of their inability to use fumarate as ... | 1973 | 4574693 |
| bacteriophage p1 derivatives with bacterial genes: a heterozygote enrichment method for the selection of p1dpro lysogens. | 1973 | 4576347 | |
| transport systems for alanine, serine, and glycine in escherichia coli k-12. | at least two transport systems serve for the entry of alanine, glycine, and serine into escherichia coli. one of these systems serves mainly for glycine, d-alanine, and d-serine and to some extent for l-alanine, whereas the second serves for l-alanine and perhaps l-serine. these two transport systems have been characterized by kinetic studies and by inhibition analysis. reciprocal plots for l-alanine entry are distinctly biphasic, giving rise to k(m) values of about 2 and 27 mum. the major route ... | 1973 | 4583203 |
| the deoxyribonucleic acid-modification enzyme of bacteriophage p1. subunit structure. | the bacteriophage p1 modification enzyme was purified 1400-fold from induced lysogens of a thermoinducible mutant of bacteriophage p1. the most purified fraction, when analysed by polyacrylamide-gel electrophoresis in sodium dodecyl sulphate, showed two principal stained bands. the two bands co-sedimented in a glycerol gradient with the modification activity, at a rate which, when compared with the rate of sedimentation of marker proteins, corresponds to a sedimentation coefficient in water of 6 ... | 1973 | 4584025 |
| evolution of l-1, 2-propanediol catabolism in escherichia coli by recruitment of enzymes for l-fucose and l-lactate metabolism. | a mutant strain of escherichia coli capable of growth on l-1,2-propanediol was isolated previously. the mutant is characterized by constitutive production of a propanediol:nicotinamide adenenine dinucleotide (nad) oxidoreductase which is essential for the new growth property. in the present study, it is shown that phage p1 cotransduces the genetic locus conferring this property and the genes for the utilization of l-fucose. a further indication of a relationship between these two growth properti ... | 1974 | 4595205 |
| transfection of escherichia coli by bacteriophage p1 dna. | 1974 | 4595551 | |
| phage p1 mutants with altered transducing abilities for escherichia coli. | 1974 | 4598709 | |
| genetic mapping of the locus for detergent-resistant phospholipase a(plda) in escherichia coli k-12. | an escherichia coli k-12 mutant deficient for detergent-resistant (dr) phospholipase a, a principal enzyme catalyzing the first step in phospholipid degradation, was characterized genetically. the mutation was found to affect the locus plda (phospholipid degradation), which is cotransducible both with ilv and mete at a frequencies of 13 and 78%, respectively, and shown to lie between the ilv and mete loci on the e. coli chromosome. dr phospholipase a(1) and a(2) activities were simultaneously tr ... | 1974 | 4604508 |
| mapping of a mutation, polb100, affecting deoxyribonucleic acid polymerase ii in escherichia coli k-12. | direct assay for deoxyribonucleic acid polymerase ii in extracts has been used to screen recombinants for the polb allele in hfr x f(-) crosses, f-ductants in episome transfer, and transductants in generalized transduction by phage p1. the polb gene is located at 2 min on the escherichia coli linkage map; it is 39 to 64% co-transducible with leu. a mutant, e. coli pola1 polb100 polc (ts), deficient in deoxyribonucleic acid polymerases i and ii and having a thermolabile deoxyribonucleic acid poly ... | 1974 | 4604726 |
| replication of deoxyribonucleic acid in escherichia coli c mutants temperature sensitive in the initiation of chromosome replication. | an escherichia coli hf4704s mutant temperature sensitive in deoxyribonucleic acid (dna) synthesis and different from any previously characterized mutant was isolated. the mutated gene in this strain was designated dnah. the mutant could grow normally at 27 c but not at 43 c, and dna synthesis continued for an hour at a decreasing rate and then ceased. after temperature shift-up, the increased amount of dna was 40 to 50%. when the culture was incubated at 43 c for 70 min and then transferred to 2 ... | 1974 | 4605049 |
| modification-deficient mutants of bacteriophage p1. i. restriction by p1 cryptic lysogens. | 1973 | 4610987 | |
| a turbid plaque-forming mutant of phage p1 that cannot lysogenize escherichia coli. | 1974 | 4610991 | |
| the bacteriophage p1 restriction endonuclease. | 1974 | 4615158 | |
| recipient gene duplication during generalized transduction. | an hfr13 delta(proa-lac) deletion recipient, -delta(proa-lac)-f-pure(+)-, has been utilized in a study of the origins of duplications formed during chromosome fragment integration. among the pro(-)lac(+) transductants, some have duplications spanning the f locus. these transductants are, or segregate, strains with f' episomes carrying genes of the duplication. some of the duplications include pure(+), a gene which is not coinherited with lac(+) during bacteriophage p1-mediated transduction. thus ... | 1974 | 4615976 |
| recombination of phage p1 in recombination deficient hosts. | 1973 | 4712391 | |
| interaction of colicins with bacterial cells. 3. colicin-tolerant mutations in escherichia coli. | mutants that adsorb certain colicins without being killed, i.e., tolerant mutants (tol), were isolated from escherichia coli k-12 strains. selection was done either with colicin k or e2. several groups of mutants showing different phenotypes were found, and some of them showed tolerance to both k and e colicins, which have different receptors. many of these mutants mapped near gal. typical mutants from group ii, iii, and iv were studied in more detail. the mutant loci were contransducible with g ... | 1967 | 4860908 |
| ultraviolet sensitivity gene of escherichia coli b. | the ultraviolet sensitivity gene of escherichia coli b was introduced into a k-12 recipient by transduction with phage p1. the uvs gene of e. coli b is cotransducible with the proc locus of k-12, is closely linked to tsx, is not linked to lacz, and only rarely to pure. the transductants are mucoid, filamentous on irradiation, and show plating-medium response. the order of markers is lacz proc tsx uvs pure. | 1968 | 4870274 |
| partial reactivation of irradiated phage p1 by strain bs2 of escherichia coli. | 1968 | 4880558 | |
| genetic studies on bacteriophage p1. | 1968 | 4881411 | |
| transduction of various r factors by phage p1 in escherichia coli and by phage p22 in salmonella typhimurium. | r factors fi(+) and fi(-), with various combinations of drug-resistance markers and isolated from independent sources, were transduced by phage p1kc in escherichia coli and by phage p22 in salmonella typhimurium. usually the entire r factor was transduced by p1kc in e. coli, as indicated by the absence of segregation of the drug-resistance markers from their conjugal transferability. in contrast, the patterns of segregation of the drug-resistance markers and their conjugal transferability differ ... | 1968 | 4882025 |
| infection by bacteriophage p1 and development of host-controlled restriction and modification and of lysogenic immunity. | shigella dysenteriae cells were infected with phage p1 or p1cl. the outcome of superinfection of these cells with phage t1.sh or t1.sh(p1) or p1cl was studied as a function of time after the initial infection. cells undergoing either a lytic response or a lysogenic response to the primary infection develop the ability to specifically restrict t1.sh between 30 and 45 min. between 15 and 30 min, the cells seem to develop the ability to produce t1.sh(p1) after infection by t1.sh. however, reasons a ... | 1969 | 4890618 |
| mutation in gal u gene of e. coli blocks phage p1 infection. | 1969 | 4891220 | |
| temperature-sensitive repression of the tryptophan operon in escherichia coli. | mutants of escherichia coli exhibiting temperature-sensitive repression of the tryptophan operon have been isolated among the revertants of a tryptophan auxotroph, trps5, that produces an altered tryptophanyl transfer ribonucleic acid (trna) synthetase. unlike the parental strain, these mutants grew in the absence of tryptophan at high but not at low temperature. when grown at 43.5 c with excess tryptophan (repression conditions), they produced 10 times more anthranilate synthetase than when gro ... | 1969 | 4895848 |
| multiplication of bacteriophage p1 mutants in shigella dysenteriae strain sh(p1). | from bacteriophage p1, 10 mutants (p1cl) were isolated which are impaired in their ability to lysogenize shigella dysenteriae sh and which fail to make plaques when plated on sh(p1). when sh(p1) is infected with p1cl, a considerable proportion of the infected cells is converted into infectious centers, which eventually release p1cl but not p1. this phage release occurs over a period of several hours, during which a manyfold multiplication of infectious centers takes place. in the course of this ... | 1968 | 4913986 |
| cotransduction of stra and ribosomal protein cistrons in escherichia coli-salmonella typhimurium hybrids. | genetic mapping of ribosomal protein cistrons of salmonella typhimurium and escherichia coli was performed by phage p1 mediated, generalized transduction. from an e. coli hybrid strain which carried a s. typhimuirum f' factor, an e. coli strain was constructed which had integrated s. typhimurium genetic material including the region of the stra locus. salmonella genetic material from this hybrid was transduced into e. coli recipients. the ribosomal protein electrophoretic patterns of these hybri ... | 1971 | 4929285 |
| new suppresor in escherichia coli. | during the genetic mapping of a mutation in the phes gene which confers temperature sensitivity on a strain of escherichia coli k-12, an extragenic suppressor was discovered which restores ability to grow at the restrictive temperature. the suppressor, which has been named supq, is cotransduced by bacteriophage p1 with the pure marker. supq does not suppress a number of amber or ochre mutations. supq(-) is carried by the prototrophic hfr hayes strain ab259, and the presence of the supq(-) allele ... | 1971 | 4937784 |
| the deoxyribonucleic acid modification enzyme of bacteriophage p1. | the bacteriophage p1 modification enzyme, assayed by the specific methylation of unmodified bacteriophage 82 dna, has been purified 500-fold from a bacteriophage p1 lysogen of escherichia coli. the enzyme catalyses the incorporation of approximately 20-24 methyl groups per bacteriophage 82 dna molecule. the sole product of methylation is 6-methylaminopurine. methylation of unmodified bacteriophage dna confers protection against a challenge by purified bacteriophage p1 restriction enzyme. the ph ... | 1972 | 5073742 |
| transduction of the nitrogen-fixation genes in klebsiella pneumoniae. | the bacteriophage p1 infects and functions as a generalized transducing phage for nitrogen-fixing strains of the coliform bacterium klebsiella pneumoniae. bacterial mutants (nif(-)) unable to grow on molecular nitrogen as a nitrogen source were found to be deficient in nitrogenase activity as assayed by the conversion of acetylene to ethylene. these mutants regained normal nitrogenase activity and the ability to grow on n(2) after transduction with lysates of p1 phage prepared from wild-type bac ... | 1971 | 5288365 |
| phage p1 modification of bacterial dna studied by generalized transduction. | 1966 | 5331504 | |
| clear plaque mutants of phage p1. | 1970 | 5444276 | |
| isolation and characterization of a glucosamine-requiring mutant of escherichia coli k-12 defective in glucosamine-6-phosphate synthetase. | a mutant was isolated from escherichia coli k-12 which requires glucosamine or n-acetylglucosamine for growth. depriving the mutant of glucosamine resulted in a rapid loss of viability of the cells, followed by a decrease in the turbidity of the culture. when the mutant cells were resuspended in broth media containing 10% sucrose, the rod-shaped cells became spheroplasts. however, the presence of sucrose in the media did not prevent the cells from losing their viability. this mutant was shown to ... | 1971 | 5541523 |
| isolation and characterization of a new generalized transducing bacteriophage different from p1 in escherichia coli. | a new generalized transducing bacteriophage in the escherichia coli system was isolated and characterized. this phage, designated d108, makes clear plaques on e. coli k-10, k-12, k-12(p1kc), k-12(d6), b/r, c, and 15 t(-), and shigella dysenteriae. the plaque of phage d108 is larger in size than that of phage p1kc. electron-microscopic observation revealed that phages d108 and p1kc are morphologically different from each other, suggesting that phage d108 belongs to a phage group different from ph ... | 1971 | 5543429 |
| transducing fragments in generalized transduction by phage p1. ii. association of dna and protein in the fragments. | 1965 | 5883908 | |
| transducing fragments in generalized transduction by phage p1. 3. studies with small phage particles. | 1965 | 5883909 | |
| transducing fragments in generalized transduction by phage p1. i. molecular origin of the fragments. | 1965 | 5883923 | |
| location and analysis of nucleotide sequences at one end of a putative lac transposon in the escherichia coli chromosome. | a segment of escherichia coli dna that contained a discontinuity of homology with salmonella typhimurium dna was isolated. the segment, 1,430 base pairs long, was derived from one end of the lac "loop," a region of about 12 kilobase pairs of e. coli dna, including the lac operon which has no detectable homology with s. typhimurium dna (k. lampel and m. riley, mol. gen. genet. 186:82-86, 1982). the nucleotide sequence of the 1,430-base-pair segment of dna was determined. the location of the junct ... | 1984 | 6086580 |
| characterization of generalized transducing phage phi w39 heteroimmune to phage p1 in escherichia coli w39. | generalized transducing phage similar to phage p1 in escherichia coli was isolated from e. coli w39, an antigenic test strain of the o121 group. this phage, designated phi w39, was reciprocally heteroimmune to phages p1 and p7, but nonreciprocally heteroimmune to phage d6. transduction experiments using various r plasmids with different molecular weights suggested that phage phi w39 could transduce at least 65 megadaltons dna. as in the case of p1 prophage, phi w39 prophage existed as a plasmid ... | 1984 | 6087089 |
| is30, a new insertion sequence of escherichia coli k12. | three independent spontaneous mutations of prophage p1 affecting the ability of the phage to reproduce vegetatively are due to the insertion of a mobile genetic element, called is30. the same sequence is also carried in the r plasmid nr 1-basel, but not in the parental plasmid nr 1. southern hybridisation study indicates that the escherichia coli k 12 chromosome carries several copies of is30 as a normal resident. is30 is 1.2 kb long and contains unique restriction cleavage sites for bglii, clai ... | 1984 | 6090868 |
| reduction of marker discrimination in transductional recombination. | the recovery of phage p1 mediated transductants varies with the marker selected in a manner which cannot be fully accounted for by dosage differences in the donor gene population. this variation in transduction frequency is due primarily to recombinational discrimination in the recipient cell. we show here that increasing the intracellular level of reca protein, which might be expected to increase the contribution of recf mediated events to recombinant formation, decreases this discrimination sl ... | 1984 | 6090869 |
| construction of tn5 lac, a transposon that fuses lacz expression to exogenous promoters, and its introduction into myxococcus xanthus. | a promoterless trp-lac fusion fragment was inserted near one end of the bacterial transposon tn5 in the correct orientation to fuse lacz gene expression to promoters outside tn5. the resulting transposon, tn5 lac, retains the kanamycin-resistance gene of tn5 and transposes in escherichia coli at 6% the frequency of tn5 to many different sites in a bacteriophage lambda target. expression of beta-galactosidase, the product of the lacz gene, from tn5 lac insertions in phage lambda depends both on i ... | 1984 | 6091110 |
| sn-glycerol-3-phosphate auxotrophy of plsb strains of escherichia coli: evidence that a second mutation, plsx, is required. | sn-glycerol-3-phosphate auxotrophs defective in phospholipid synthesis contain a km-defective sn-glycerol-3-phosphate acyltransferase. detailed genetic analysis revealed that two mutations were required for the auxotrophic phenotype. one mutation, in the previously described plsb locus (sn-glycerol-3-phosphate acyltransferase structural gene), mapped near min 92 on the escherichia coli linkage map. isolation of tn10 insertions cotransducible with the auxotrophy in phage p1 crosses revealed that ... | 1984 | 6094487 |
| bacteriophage p1 carries two related sets of genes determining its host range in the invertible c segment of its genome. | the bacteriophage p1 genome carries an invertible c segment consisting of 3-kb unique sequences flanked by 0.6-kb inverted repeats. host range mutations of p1 have been mapped in the c segment region. p1 derivatives carrying insertions and deletions in the left half of the c segment in one of two orientations termed c(+) do not affect the plaque-forming ability on escherichia coli k12 and e coli c, whereas those having insertions in the right half of the c segment fail to form plaques on these h ... | 1984 | 6100576 |
| a cointegrate of the bacteriophage p1 genome and the conjugative r plasmid r100. | 1980 | 6100897 | |
| effects of glnl and other regulatory loci on regulation of transcription of glna-lacz fusions in klebsiella aerogenes. | mutants of klebsiella aerogenes containing genetic fusions of glna to lacz were isolated by using mu dl (lac, bla) bacteriophage and a mu kmr helper phage with the host range of bacteriophage p1. synthesis of beta-galactosidase in these strains is regulated in response to nitrogen metabolites and regulatory gln loci and is rendered constitutive by a mutation in the linked glnl gene. complementation studies indicated that glnl is a separate locus from glna and glng and that insertions in glna are ... | 1982 | 6120932 |
| studies on the properties of p1 site-specific recombination: evidence for topologically unlinked products following recombination. | bacteriophage p1 encodes its own site-specific recombination system consisting of a site at which recombination takes place called loxp and a recombinase called cre. a number of lambda and plasmid substrates containing two loxp sites have been constructed. using these substrates we have shown both in vivo and in vitro that a fully functional loxp site is composed of no more than 60 bp. in vitro, when an extract containing cre is used, recombination between loxp sites on supercoiled, nicked-circl ... | 1983 | 6220808 |
| replication-control functions block the induction of an sos response by a damaged p1 bacteriophage. | uv-damaged bacteriophage p1 causes an sos response in infected bacteria that can be measured colorimetrically with the aid of a lambda pl-lacz fusion strain of escherichia coli. this response is blocked by a p1 prophage. evidence is offered that the blockage is caused by the concerted action of the incompatibility determinant inca and the immunity (c1 and c4) repressors of the prophage. we suggest that indirect induction of lambda by damaged p1 is caused by the abortive initiation of replication ... | 1983 | 6227794 |
| site-specific recombinational circularization of bacteriophage p1 dna. | 1983 | 6228057 | |
| interaction of the bacteriophage p1 recombinase cre with the recombining site loxp. | the interaction between the p1 recombinase protein cre and the dna site at which it acts, loxp, has been studied by using nuclease protection techniques. the region of dna protected by cre against nuclease attack by dnase i or neocarzinostatin is a 34-base-pair (bp) region containing two 13-bp inverted repeats separated by an 8-bp spacer region. these protected sequences have previously been shown to be required for efficient cre-mediated recombination at loxp. the results of the above protectio ... | 1984 | 6230671 |
| effect of bacteriophage p1 lysogeny on lipopolysaccharide composition and the lambda receptor of escherichia coli. | the outer membrane of escherichia coli was altered as a consequence of lysogeny by bacteriophages p1 and p1 cmts. the predominant change was a reduction in the size of lipopolysaccharide to a heptose-deficient form. p1 cmts lysogens were still sensitive to several bacteriophages but were resistant to lambda vir. neither whole cells nor solubilized outer membranes from p1 cmts lysogens were able to inactivate lambda vir, and 32p-labeled lambda vir was unable to adsorb to p1 cmts lysogens. p1 cmts ... | 1984 | 6237098 |
| on the role of is1 in the formation of hybrids between the bacteriophage p1 and the r plasmid nr1. | 1980 | 6245339 | |
| bacteriophage p1 as a vehicle for mu mutagenesis of salmonella typhimurium. | we developed a procedure using bacteriophage p1 as a vector for transferring mu phage deoxyribonucleic acid into salmonella typhimurium. mu phage transferred in this manner yielded lysogenic auxotrophs, and we demonstrated that specific deletions and lac gene fusions can be selected. | 1980 | 6253444 |
| denaturation map of bacteriophage p1 dna. | 1981 | 6259828 | |
| transposon mutagenesis of the gene encoding the bacteriophage p1 restriction endonuclease. co-linearity of the gene and gene product. | 1980 | 6265645 |