Showing papers on "Lambda phage published in 1970"
TL;DR: In this article, it was shown that psoralen cross-links may contribute to the skin photosensitizing action observed for phage λ DNA in vitro and Escherichia coli DNA in intact bacterial cells.
300 citations
TL;DR: A phage lambda gene, called tof, responsible for the turnoff of λ-exonuclease synthesis during the lytic cycle has been located in the region of the lambda genome which is nonhomologous with the λi 434 genome.
94 citations
TL;DR: Phage λ dissociates in boiling SDS into at least three major and three minor proteins, which separate from each other in gel electrophoresis, and by purifying the resulting complete phage particles it was possible to identifyThree of the proteins as constituents of the head and three of the tail.
90 citations
TL;DR: Transducing variants of coliphage λ have been isolated from a donor strain in which the normal prophage-host relationship is altered by a deletion that extends from the galE gene of the host into the Q gene ofThe prophages, apparently by shortening the latent period.
47 citations
TL;DR: An in vivo assay for the product of the N gene of bacteriophage lambda shows that expression of theN gene starts during the first minute of the vegetative cycle and the amount of N product synthesized by wild-type phage lambda is in large excess of what is required to obtain maximum expression ofThe early genes located to the left of N.
37 citations
37 citations
Journal Article•
20 citations
20 citations
TL;DR: The analysis of the bio A locus of Escherichia coli was made possible through the use of HFT lysates of different λdbio transducing phages and shows that the various λ dbio particles can persist as nonintegrated phage genomes and must be replicated to some degree, presumably in harmony with host cell replication.
19 citations
TL;DR: Defects in the bacterial recB or recC or phage red or int gene did not impair ultraviolet light-induced clear mutations of lambda phage and no correlation was observed between UV-induced mutation and genetic recombination.
Abstract: Defects in the bacterial recB or recC or phage red or int gene did not impair ultraviolet light-induced clear mutations of lambda phage. Clear mutants of cI and cII genes were not enriched among RecA-promoted UV-induced recombinants between the N and O genes which closely encompass the c genes. No correlation was observed between UV-induced mutation and genetic recombination.
18 citations
TL;DR: It is shown for phage lambda that duplication destroys heterozygotes as predicted by the Watson-Crick model and operationally ditinguishable since the former demands that heteroduplexes are destroyed by duplication while the latter anticipates their survivial.
Abstract: The Watson-Crick model for DNA duplex duplication proposes that the two parental chains separate and that each directs the synthesis of a complementary chain with which it is found associated after the duplication act. Previous experiments have left unchallenged alternative models which propose that in any single act of duplication only one of the two parental chains provides information for the synthesis of both new chains. The models are operationally ditinguishable since the former demands that heteroduplexes are destroyed by duplication while the latter anticipates their survivial. We have shown for phage lambda that duplication destroys heterozygotes as predicted by the Watson-Crick model.A stock of lambda containing a high frequency of heterozygotes at the cI locus was prepared by conducting a cross under conditions of depressed DNA synthesis. Particles in this lysate were permitted to duplicate a few times by adsorbing them to a lambda lysogen in a (15)N (13)C medium along with a heteroimmune lambda strain. Emerging lambda particles were separated according to density. The population of particles carrying DNA of parental density retained the initial high heterozygote frequency. Among particles which had duplicated, 80 per cent or more of the heterozygotes had disappeared.
TL;DR: The much elevated level of stable transductants on induction of red− lysogens hereby is explained andsequence (2) has been confirmed.
Abstract: There are at least two classes of transducing particles made on the induction of normal λ lysogens: the first is capable of transducing by the insertion of the whole transducing genome into the host chromosome, so its genome must be capable of circularizing; the second transduces less well by insertion—perhaps not at all; if it does not transduce by insertion then its genome need not be linear. The formation of a transducing genome can be accomplished in three steps: (a) breaking the lysogenic bacterial chromosomes in two places, (b) joining the fragment ends together to form a circular structure, (c) opening the circle (by ter) to form a linear genome. If the resultant structure meets the requirements for λ packaging, it may be formed into a transducing phage, like a bougus λ. Any meaningful rearrangement of these steps in which step (b) is omitted or delayed leads to the formation of genomes, which are (1) unable to transduce by insertion (because both of its mature ends are unexposed) and (2) are on the average smaller than genomes which are capable of transducing by insertion (so the resultant transducing phage is less dense). Consequence (2) has been confirmed. We assume that the red function of λ catalyzes the joining of broken DNA molecules to each other. So red is responsible for rehealing the product of (a) back into a lysogenic chromosome and for catalyzing step (b), the healing of fragment ends into a circular structure. The much elevated level of stable transductants on induction of red
− lysogens hereby is explained.