Showing papers on "Lambda phage published in 1974"
TL;DR: The genetic mapping of a locus of the Escherichia coli chromosome involved in the expression of the N gene function of phage λ suggests that the nus + allele is responsible for theexpression of a function necessary for N product activity.
130 citations
TL;DR: The occurrence of indirect ultraviolet-reactivation provides evidence for the existence in E. coli of an inducible error-prone mechanism for the repair of DNA.
Abstract: When an F(-) recipient Escherichia coli K12 bacterium receives Hfr or F-lac(+) DNA from an ultraviolet-irradiated donor, its capacity to promote DNA repair and mutagenesis of ultraviolet-damaged phage lambda is substantially increased. We call this phenomenon indirect ultraviolet-reactivation, since its features are essentially the same as those of ultraviolet-reactivation; this repair process occurs in pyrimidine dimer excision-deficient strains and produces clear plaque mutations of the restored phage. Moreover, this process is similar to indirect ultraviolet-induction of prophage lambda, since it is promoted by conjugation. However, contrarily to indirect induction, it is produced by Hfr donors and occurs in recipients restricting the incoming ultraviolet-damaged donor DNA. The occurrence of indirect ultraviolet-reactivation provides evidence for the existence in E. coli of an inducible error-prone mechanism for the repair of DNA.
88 citations
TL;DR: It is concluded that the pel − mutant allows adsorption of λ but that it inhibits the subsequent injection of the phage DNA.
78 citations
TL;DR: A precursor head of phage lambda is synthesized after induction of cells lysogenic for λD-F- and λA- (head-defective) mutants and can be assayed by complementation in vitro and purified by CsCl gradient centrifugation and sucrose gradient sedimentation.
Abstract: A precursor head of phage lambda is synthesized after induction of cells lysogenic for λD-F- and λA- (head-defective) mutants. This precursor head can be assayed by complementation in vitro and can be purified by CsCl gradient centrifugation and sucrose gradient sedimentation. The precursor head contains no DNA and has the same dimensions as the petit λ particle. It can be packed with λ DNA in an extract from induced Escherichia coli lysogenic for a λE- mutant.
70 citations
63 citations
TL;DR: E. coli RNA polymerase binds to a specific site within each λ operator, which is recognised by three proteins:RNA polymerase, the λ phage repressor, and a restriction endonuclease (Hin).
Abstract: E. coli RNA polymerase binds to a specific site within each λ operator. This DNA site is recognised by three proteins: RNA polymerase, the λ phage repressor, and a restriction endonuclease (Hin).
59 citations
TL;DR: Characterization of the plasmids obtained indicates that the replication genes O and P, a regulatory gene cro, and sequences in the operator-promoter region which control the transcription of cro, O and F are important and regulatory genes c I and c II play no indispensable role.
57 citations
TL;DR: That zygotic induction of 186 after transfer from a lysogenic male to a non-lysogenic recipient did not occur is indicated by the following findings: there was only a slight increase in phage titer; similar levels of recombinants were obtained for markers adjacent or distal to the phage integration site, whether the recipient wasLysogenic or not, and there was no effect on the gradient of marker transfer.
Abstract: Coliphage 186 has been regarded as a member of the noninducible group of coliphages. Evidence that prophage 186 is induced by ultraviolet irradiation or by treatment with nalidixic acid or mitomycin C is now presented. The phage yields were similar to those from lysogens of the inducible phage lambda, and the induction required a recA(+) host. A noninducible mutant of 186 was isolated from its heat-inducible derivative, 186cIts, that was no longer inducible by ultraviolet irradiation but remained heat inducible. That zygotic induction of 186 after transfer from a lysogenic male to a non-lysogenic recipient did not occur is indicated by the following findings: (i) there was only a slight increase in phage titer; (ii) similar levels of recombinants were obtained for markers adjacent or distal to the phage integration site, whether the recipient was lysogenic or not, and there was no effect on the gradient of marker transfer; (iii) lysogenic recombinants were readily found and the co-transfer of 186 with adjacent markers was the same to lysogenic or non-lysogenic recipients. Thus, 186 formed an inducible prophage that did not display zygotic induction. Nevertheless, it shared many properties with the noninducible phage P2 as outlined in the discussion.
34 citations
TL;DR: The possibility that the radiation-induced radicals responsible for cell killing and for DNA strand breakage are different was studied by determining their relative reactivities towards oxygen.
Abstract: The possibility that the radiation-induced radicals responsible for cell killing and for DNA strand breakage are different was studied by determining their relative reactivities towards oxygen under physiological conditions. The yield of x-ray-induced DNA single-strand breaks was determined by measuring the breaks in covalently closed circular λ DNA molecules superinfecting lysogenic strains of Escherichia coli K12. In the presence of oxygen the frequency of DNA breakage is four- to fivefold higher than under nitrogen anoxia. The concentration of oxygen that increases DNA breakage to half the maximal level, k, is 0.5 μM and is similar in repair proficient host cells and in cells mutated in the uvrA and/or recA genes. Intermediate levels of DNA strand breakage seen at low concentrations of oxygen are dependent on the concentration of cellular sulfhydryl compounds. The effectiveness of oxygen under comparable conditions in enhancing the radiation-induced killing of the non-lysogenic bacterial strains was de...
33 citations
TL;DR: Lambda phage particles were disrupted by treatment with 50–60% formamide and subsequent spreading on a meniscus of ammonium acetate solution and analyzed by electron microscopy to derive a phage DNA molecule of which the “right-hand” end is attached to the proximal end of a tail.
31 citations
TL;DR: Six of seven hfl mutations of Escherichia coli K12, characterized by high frequencies of lysogenization by phage lambda and lambdacIII mutants, are shown to be tightly linked to, but not within, the purA locus.
Abstract: Six of seven hfl mutations of Escherichia coli K12, characterized by high frequencies of lysogenization by phage lambda and λcIII mutants, are shown to be tightly linked to, but not within, the purA locus. All six hfl mutations are recessive to wild type in hfl+/hfl merodiploids and all lie in a single complementation group, located just counterclockwise from the purA locus. All six mutations confer a slightly increased resistance to penicillin and rifamycin and a slightly increased sensitivity to sodium dodecyl sulfate. Some cases of intragenic complementation and intragenic recombination were observed. It is argued that the hfl+ gene determines the synthesis of a protein which antagonizes lysogenization by phage lambda. It is further argued that the function of the λcIII gene product is to negate the antagonistic effect of this hfl+ protein.
TL;DR: Measurements are consistent with the notion that it is the deletion of the t L terminator which permits the p L -promoted transcription to extend from the λ genome into the trp operon, even when synthesis of the N product is blocked by chloramphenicol.
TL;DR: The lambdadvgal plasmid can be introduced into a new bacterial host by transfection at an efficiency of 10(-6) per DNA molecule.
Abstract: A lambdadvgal plasmid carrying genes for controlled plasmid replication from phage lambda and the bacterial gal operon was isolated as a deletion mutant of phage lambdagalq4, which carries the gal operon between lambda genes P and Q. The plasmid DNA was found in cell extracts as covalently closed circular molecules. The plasmid was characterized by using genetic crosses, digestion with the specific endonuclease EcoRI, sucrose gradient centrifugation, and electron microscopy. In one clone analyzed, the plasmid was a complete dimer (O(lambda)P(lambda)galO(lambda)P(lambda)gal); in a subclone derived from it, the plasmid was a partial dimer with only one copy of gal (O(lambda)P(lambda)O(lambda)P(lambda)gal). The partial dimer may be a recombination product of the complete dimer, since test crosses show that the gal and lambda sequences in the plasmid can be separated by recombination. Analyses of the EcoRI digests of plasmid DNAs indicated one cleavage site per lambda gene sequence and none in the gal operon. A lambdadvgal monomer was approximately 6.7 x 10(6) daltons and the lambda gene and gal components were 3.9 x 10(6) and 2.8 x 10(6) daltons, respectively. The lambdadvgal plasmid can be introduced into a new bacterial host by transfection at an efficiency of 10(-6) per DNA molecule.
TL;DR: An Escherichia coli mutant, which was originally isolated as colicin tolerant and is defective in a membrane protein, alters the regulation of bacteriophage λ with a strong preference to lysogeny over the lytic pathway.
TL;DR: The rate of λ dv replication is limited by the frequency of a transcription event required in cis, and implementation of O and of P phage by λdv shows that O and P products are present in excess in λDv carrier cells.
TL;DR: In wild-type cells, phage-induced radioresistance requires some interaction between the bacterial recB gene product (exonuclease V) and the phage lambda-protein, and this occurs in recB(+) lysogens even when they carry lambda red(-), but not when the lambda prophage is gam(-).
Abstract: E. coli cells lysogenic for the thermoinducible prophage λcI857 can be transiently induced by a brief heat treatment. Although this treatment does not kill the cells, some λ products normally formed during vegetative phage development are made that can alter the response of host cells to x-irradiation by causing an increase in radioresistance. This increased resistance is particularly striking in the recombination-deficient recB-strain, which is normally much more radiosensitive than its recB+ parent. After pulse-heating at 42°, the survival curve of E. coli recB- lysogenized with λcI857 does not differ from that of the wild-type strain. Since λ red mutants do not increase the radioresistance of recB- strains, both λ red gene products, λ exonuclease and β-protein, are required to compensate for the missing recB product. Furthermore, phage-induced radioresistance also occurs in recB+ lysogens even when they carry λ red-, but not when the λ prophage is gam-. Thus, in wild-type cells, phage-induced radioresistance requires some interaction between the bacterial recB gene product (exonuclease V) and the phage λ-protein.
TL;DR: In this article, a phage DNA transfection assay was described that permits the measurement of frequencies of recombinant DNA molecules, and this method was used to investigate the time course of action of the phage-specified generalized recombination system, the Red system, during lytic infection.
Abstract: A phage DNA transfection assay is described that permits the measurement of frequencies of recombinant DNA molecules. This method was used to investigate the time course of action of the phage-specified generalized recombination system, the Red system, during lytic infection. Two observations of interest have emerged from this study: 1. There is a distinct lag before significant numbers of recombinant molecules are detected. 2. The presence of an active recB gene product in host cells produces an early shut-off of recombination.
TL;DR: W Whole phage was more resistant to the action of γ-rays than was isolated DNA, and the chemical agents HNO 2 and MNNG inactivated phage much faster than isolated DNA.
Abstract: Inactivation of λ 11 c and its purified DNA by UV irradiation, γ-rays of 137 Cs (in conditions of indirect action), nitrous acid, hydroxylamine and N -methyl- N ′-nitro- N -nitrosoguanidine (MNNG) was studied. The biological activity of isolated phage DNA was measured by the calcium transfection procedure. 14 different recipient strains of Escherichia coli K12 were used, including mutants deficient in excision and recombination repair ( uvrA6, uvrB5, uvrC34, polA1, recA13, recC38, recD34, recA13B21C22, recA56uvrA6, exrA and recB21C22sbcB15 ). Whole phage was more resistant to the action of γ-rays than was isolated DNA. On the other hand, the chemical agents HNO 2 and MNNG inactivated phage much faster than isolated DNA. Of all mutations of the host cell only polA1 considerably increased the sensitivity of phage DNA to UV irradiation, γ-rays and MNNG. The mutations uvr − affected the inactivation kinetics under UV action. In all other cases the genotype of the host cell was indifferent for the inactivation kinetics of phage DNA, even if it belonged to recombination deficient mutant λ red3 int6 (in which only UV and γ inactivation was studied). Possible reasons for the low efficiency of the host-cell repair toward the damage caused to λ DNA by different agents are discussed.
TL;DR: Examination of the progeny phage produced by the population of mixedly-infected cells showed that there was little, if any, phenotypic mixing, as determined by adsorption phenotype.
Abstract: Bacteria containing phage lambda in the vegetative state were produced either by induction of lambda lysogens or by infection of sensitive cells with lambda. These cells were superinfected with T1, and assayed for the production of lambda, T1, or both. Although most of the cells produced only lambda or T1, approximately 10% of the infectious centers were dual yielders. Examination of the progeny phage produced by the population of mixedly-infected cells showed that there was little, if any, phenotypic mixing, as determined by adsorption phenotype. T1am mutants in a variety of T1 genes were tested for their ability to exclude lambda, but none were defective in this ability. One gene of T1, gene 4, can be complemented by lambda.
TL;DR: The am − am + progeny ratios approached the input ratios when the defective phage carried mutations in genes N and P, but not in genes A, V, O, and J, suggesting that restriction to the number of genomes that can be used as templates for progeny phage DNA synthesis takes place only during the second stage of DNA replication.
TL;DR: Lambda FIIam mutants produce a normal yield of head particles which contain mature DNA, but are defective in head-tail joining, so genetic function of λDNA in the injectable subpopulation is apparently normal.
TL;DR: A mutant of Escherichia coli temperature-sensitive for deoxyribonucleic acid synthesis, dnaD, was found to have temperature- sensitive modification and restriction phenotypes and allowed some growth of unmodified lambda.
Abstract: A mutant of Escherichia coli temperature-sensitive for deoxyribonucleic acid synthesis, dnaD, was found to have temperature-sensitive modification and restriction phenotypes. In contrast to the original observation by Carl (1970), the mutant could support the growth of lambda phage at 41 C. However, the lambda phages thus produced were able to form plaques with normal plating efficiency only on E. coli C, a restriction-less strain, but not on E. coli K. Since the lambda phages produced in the mutant at 30 C could form plaques equally well on both E. coli strains, it was concluded that the dnaD mutant has a temperature-sensitive modification phenotype. Furthermore, since the dnaD mutant allowed some growth of unmodified lambda.C phages at 41 C but less at 30 C, the mutant is also temperature sensitive in restriction. The relationship, if any, between temperature-sensitive deoxyribonucleic acid synthesis and temperature-sensitive modification-restriction in the dnaD mutant is not known. Similar experiments were done with three dnaC mutants and one dnaA mutant. Two dnaC mutants were found to have altered restriction phenotypes at 41 C, but none of the mutants were defective in modification.
TL;DR: The extent and location of DNA synthesis associated with Rec recombination of a lambda phage mutant has been determined approximately for recombinants arising under conditions that restrict DNA duplication.
01 Jan 1974
TL;DR: The role of recombination promoted by the Escherichia coli Rec system in the growth of deletion mutants of lambda that have lost the genes between att and cIII is summarized in this report.
Abstract: Results of experiments carried out in a number of laboratories demonstrate the interdependence of replication, recombination, and maturation in phage lambda (see, for example, the review by Stahl et al., 1973, and references cited there). The experiments summarized in this report relate to the role of recombination promoted by the Escherichia coli Rec system in the growth of deletion mutants of lambda that have lost the genes between att and cIII (Fig. 1). A detailed description of this work will be presented elsewhere (Henderson and Weil, manuscript in preparation).
TL;DR: Phage release was taken as an index of lysis, which permits to study the lysis reaction at very low substrate inputs, to devise a sensitive end-point assay which detects less than 10−3 picomole of egg white lysozyme.
TL;DR: For efficient reduction of the phage plating ability more growth steps on the new strain are required in this type of strain, because of the different host specificities O55 and J, which proved to be different from K specificity.
Abstract: Escherichia coli O55 hybrids able to adsorb the lambda phage were obtained by mating anEscherichia coli O55 recipient with anEscherichia coli K12HfrC donor. λ mutants, capable of forming plaques on these hybrids, were not isolated. A new type of host specificity betweenEscherichia coli O55 and urinaryEscherichia coli J was established. For efficient reduction of the phage plating ability more growth steps on the new strain are required in this type. Host specificities O55 and J proved to be different from K specificity.