| isolation, characterization and deletion mapping of amber mutations in the cll gene of phage lambda. | | 1975 | 1089335 |
| morphogenesis of the tail of bacteriophage lambda. ii. in vitro formation and properties of phage particles with extra long tails. | | 1975 | 1089336 |
| repressor synthesis in vivo after infection of e. coli by a prm - mutant of bacteriophage lambda. | | 1975 | 1089337 |
| genetic and phenotypic characterization of dnac mutations. | the dna-1, dna-2, dna-7, and dna-28 mutations, all of which are located near min 89.5 on the e. coli linkage map, have been characterized further. as previously demonstrated for dna-2 and dna-28, neither the dna-1 nor dna-7 mutation affects the ability of a strain to produce bacteriophage lambda at temperatures non-permissive for the continued replication of the bacterial chromosome. the reported temperature-sensitive inhibition of lambda production in a strain carrying dna-7 is shown to be a co ... | 1975 | 1089638 |
| the formation of polylysogens during infection of escherichia coli with bacteriophage lambda. | | 1975 | 1090071 |
| the role of gene nu3 in bacteriophage lambda head morphogenesis. | | 1975 | 1090075 |
| ribonucleic acid synthesis after adsorption of the bacteriophage lambda on escherichia coli minicells. | lambda bacteriophage adsorbs on the chromosome-less small bodies (minicells) produced by aberrant cell division of escherichia coli p678-54. the plasmid-less minicells, as well as the minicells harbouring the colicinogenic factor e1, reveal a considerable inhibition of total rna synthesis after phage adsorption. both kinds of minicells synthesize rna hybridizable to lambda dna, but in the plasmid-harbouring minicells lambda rna synthesis is much more intensive. | 1975 | 1090110 |
| intermolecular linking and fragmentation of dna by beta-propiolactone, a monoalkylating carcinogen. | brief exposure to beta-propiolactone (bpl) increases the sedimentation rate of purified escherichia coli dna in neutral and alkaline sucrose gradients. however, when electrophoresed in polyacrylamide-agarose gels, this bpl-treated dna moves ahead of the control. longer incubation with bpl gives rise to two new fractions, the first one sedimenting as a heterogeneous material of 6-8s, and the second one of very high sedimentation velocity. in acrylamide-agarose gels, the first fraction is again re ... | 1975 | 1090389 |
| occurrence of the bacteriophage lambda receptor in some enterobacteriaceae. | in escherichia coli k-12, the receptor for phage lambda is an outer membrane protein which inactivates the phage in vitro. lambda receptor activity was found in extracts from all wild strains of e. coli tested, although most of them fail to support growth of the phage. in some cases this failure is due to a masking of the receptor in vivo, the bacteria being unable to adsorb the phage or to react with antireceptor antibodies. in other cases, adsorption does occur, and the nature of the block in ... | 1975 | 1090748 |
| proteolytic cleavage of bacteriophage lambda repressor in induction. | the bacteriophage lambda repressor, a protein that maintains the lysogenic state of a bacterium containing a lambda prophage, is cleaved when the lysogen is induced by mitomycin c or ultraviolet light. this cleavage does not occur when induction is prevented by mutational alteration either of the phage repressor or of the host reca gene product. proteolytic cleavage may be the primary mechanism of repressor inactivation in this induction pathway, or it may follow a different event which causes t ... | 1975 | 1090931 |
| replicating circular dna molecules in yeast. | the yeast saccharomyces cerevisiae contains a class of small circular dna molecules, approximately 2 mum in contour length (sinclair et al., 1967). in this report, it is shown that these molecules replicate as double-branched circles, similar to those observed during replication of the bacteriophage lambda and escherichia coli chromosomes. a normal rate of replication of these dna circles requires the function of a nuclear gene, cdc 8. | 1975 | 1091361 |
| deoxyribonucleic acid-cytosine methylation by host- and plasmid-controlled enzymes. | deoxyribonucleic acid (dna)-cytosine methylation specified by the wild-type escherichia coli k 12 mec+ gene and by the n-3 drug resistance (r) factor was studied in vivo and in vitro. phage lambda and fd were propagated in the presence of l-[methyl-3h]methionine in various host bacteria. the in vivo labeled dna was isolated from purified phage and depurinated by formic acid-diphenylamine treatment. the resulting pyrimidine oligonucleotide tracts were separated according to size and base composit ... | 1975 | 1091619 |
| mutations simultaneously affecting endonuclease ii and exonuclease iii in escherichia coli. | we studied mutants of e. coli originally identified as being deficient in either endonuclease ii (deoxyribonucleate oligonucleotidohydrolase, ec 3.1.4.30) or exonuclease iii [deoxyribonucleate (double-stranded) 5'-nucleotidohydrolase, ec 3.1.4.27] activity. twelve independently derived mutants were tested, including three new endonuclease ii mutants. deficiency of one enzyme was always accompanied by deficiency of the other. furthermore, temperature-sensitivity of one activity was always accompa ... | 1975 | 1091930 |
| insertion of a minor protein into the outer membrane of escherichia coli during inhibition of lipid synthesis. | the antibiotic cerulenin, a specific inhibitor of fatty acid synthetase systems, was used to demonstrate that a minor protein component of the outer membrane of escherichia coli, which serves as the receptor for the phage lambda, can be synthesized and inserted into the outer membrane during inhibition of lipid synthesis. | 1975 | 1092644 |
| electron microscope heteroduplex studies of sequence relations among bacterial plasmids: identification and mapping of the insertion sequences is1 and is2 in f and r plasmids. | heteroduplex experiments between the plasmid r6 and one strand of the deoxyribonucleic acid (dna) of a lambda phage carrying the insertion sequence is1 show that is1 occurs on r6 at the two previously mapped junctions of resistance transfer factor (rtf) dna with r-determinant dna. from previous heteroduplex experiments, it then follows that is1 occurs at the same junctions in r6-5, r100-1, and r1 plasmids. heteroduplex experiments with the dna from a lambda phage carrying the insertion sequence ... | 1975 | 1092668 |
| ultraviolet reactivation and ultraviolet mutagenesis of infectious lambda dna: strong inhibition by treatment of dna in vitro with uv-endonuclease from micrococcus luteus. | uv-endonuclease from microcossuc luteus induces single-stranded breaks in uv-irradiated dna of phage lambda and the average length of the fragments produced (after uv-doses to dna of 135 and 675 erg/mm2) is equal to the average spacing between pyrimidine dimers. the plaque-forming ability of uv-irradiated lambda dna used to infect ca++-treated uvr a6, uvrb5 or uvrc34 recipient escherichia coli cells (but not uve+ cells) may be significantly enhanced by treatment of lambda dna with uv-endonucleas ... | 1975 | 1093009 |
| a mutant of eshcerchia coli k-12, urt-43, with a temperature-sensitive defect at the incision step of the excision repair mechanism. | urt-43, which has a defect in excision repair, exhibits a temperature-dependent ultraviolet survival. it was shown that urt-43 requires protein synthesis but not dna synthesis for recovery, by examining recovery in a growth medium containing chloramphenicol or nalidixic acid. the recovery of irradiated bacteriophage lambda in urt-43 took place in a medium containing nalidixic acid at 30 degrees, but not at 41 degrees, and chloramphenicol prevented this recovery. these results seem to imply that ... | 1975 | 1093010 |
| the biological activity of bacteriophage dna, prepared by the cationic detergent dilution technique. | the preparation of phage lambda dna infecting e. coli k 12 with cationic detergent is described. this dna infects e. coli spheroblasts with the same efficiency as dna prepared by phenol methods. | 1975 | 1093138 |
| recombination-deficient deletions in bacteriophage lambda and their interaction with chi mutations. | we have isolated a new class of deletion mutants of phage lambda that extend from the prophage attachment site, att, into the gam and ciii genes. in this respect they are similar to certain of the lambda pbio transducing phage, but they differ in having a low burst size and in forming minute plaques. lytically grown stocks of the deletions contain a variable proportion of phage that produce large plaques. these have been shown to carry an additional point mutation. similar mutations, called chi, ... | 1975 | 1093930 |
| resolution of the dna strands of the specialized transducing bacteriophage lambda-h80c 1-857 dargf. | the dna strands of lambdoid phages with deletions or substitutions of the guanine plus cytosine-rich region in the left arm are not resolvable by complexing with poly ug followed by centrifugation in cscl. this work describes a completely general procedure for the strand resolution of these phages by hybridization with fragments of separated strands of the parent phage. in particular, resolution of the dna strands of the specialized transducing phage lambda-h80c1-857dargf is described, and evide ... | 1975 | 1094135 |
| mismatch repair in heteroduplex dna. | dna with base pair mismatches was prepared by annealing mixtures of genetically marked dna from bacteriophage lambda. this heteroduplex dna was used to transfect bacteria under conditions minimizing recombination. genetic analysis of the progeny phages indicates that: (i) mismatch repair occurs, usually giving rise to a dna molecule with one chain with the genotype arising from repair and one parental chain. (ii) the frequency of repair of a given mismatch to wild type depends on the marker, ran ... | 1975 | 1094458 |
| uptake of homologous single-stranded fragments by superhelical dna: a possible mechanism for initiation of genetic recombination. | superhelical [3-h]dna (replicative form i, rfi) of bacteriophage phix174 slowly but spontaneously took up 32-p-labeled homologous single-stranded fragments at 4 degrees. uptake was accelerated by heating to 75 degrees. rfi did not take up single-stranded fragments derived from dna of escherichia coli or from separated strands of phage lambda. uptake was inhibited by low concentrations of ethidium bromide. relaxed circular phix174 dna did not take up homologous fragments. per molecule of rfi, the ... | 1975 | 1094467 |
| structure of the oligomeric circular molecules of a bacteriophage lambda dna. | | 1975 | 1094676 |
| deletion mutations of the immunity region of coliphage lambda. | | 1975 | 1094677 |
| constitutive integrative recombination by bacteriophage lambda. | | 1975 | 1094679 |
| recognition sequences of repressor and polymerase in the operators of bacteriophage lambda. | nucleotide sequences in two wild-type and six mutant operators in the dna of phage lambda are compared. strikingly similar 17 base pair units are found which we identify as the repressor binding sites. each operator contains multiple repressor binding sites separated by a-t rich spacers. elements of 2 fold rotational symmetry are present in each of the sites. superimposed on each operator is an e. coli rna polymerase recognition site (promoter). similarities in the sequences of the two lambda pr ... | 1975 | 1095210 |
| the promoters and bidirectional transcription in the immc region of p 22 and l phages. | it is proposed that the transcription of the c-2 repressor gene initiates at two promoters, pre and prm, similarly to the transcription of the c-i gene of lambda phage. in the p22 phage, these promoters are defined by mutations of c54 and k5. | 1975 | 1095460 |
| quantitation of the loss of the bacteriophage lambda receptor protein from the outer membrane of lipopolysaccharide-deficient strains of escherichia coli. | the recpetor for the phage lambda, a protein component of the outer membrane, is present at decreased levels in strains of escherichia coli that are deficient in lipopolysaccharide. loss of the protein was quantitated both by an assay of the phage receptor function and by an assay of antiserum-blocking ability to detect inactive protein. the loss of protein was correlated with the loss of sugar residues and phosphage from the core region of the lipopolysaccharide. implications for the importance ... | 1975 | 1095562 |
| termination of transcription in bacteriophage lambda. heterogeneous, 3'-terminal oligo-adenylate additions and the effects of rho factor. | rna transcripts were synthesized in vitro from a lambda dna template with purified escherichia coli rna polymerase either in the presence or absence of the protein termination factor, rho. the products were initially characterized by electrophoresis on polyacrylamide slab gels, and two of the lower molecular weight discrete species (6 s and 4 s rna) were further characterized by standard two-dimensional "fingerprint" analysis. production of the 4 s rna was strongly affected by the presence of rh ... | 1975 | 1095576 |
| chloramphenicol stimulation of lysogeny by lambda regulatory mutants. | inhibition of protein synthesis in escherichia coli by amino acid starvation or chloramphenicol addition increases the frequency of lysogeny by lambda phage two- to fourfold. lambda ciii mutants, which normally lysogenize at very low frequencies, lysogenize at very high frequencies in the presence of chloramphenicol. | 1975 | 1095779 |
| mechanisms of protection of gamma-irradiated bacteriophage lambda by proflavine. | the protective effect of proflavine on gamma-irradiated bacteriophage lambda and its isolated dna was investigated under conditions of predominantly indirect or direct effects. in both conditions addition of small amounts of the dye during irradiation of phage or dna was shown to enhance their biological activity. protection against indirect effects results probably from extensive scavenging of radioinduced water radicals within the medium. on the other hand the results obtained at minus 196 deg ... | 1975 | 1080138 |
| inhibitory effect of u.v. -irradiation on the formation of twisted circular lambda dna. | ultra-violet irradiation of lambda phage results in an inhibition of conversion of lambda dna in host cells from the initial linear form to twisted circular form. the formation of open circular lambda dna in vitro (formation of hershey's circle) was quite resistant to the irradiation. the occurrence of denaturation of ultraviolet irradiation was detected in lambda dna. | 1975 | 1079515 |
| improved derivative of a phage lambda ek2 vector for cloning recombinant dna. | | 1976 | 1067476 |
| purification and properties of a dna-binding protein with characteristics expected for the cro protein of bacteriophage lambda, a repressor essential for lytic growth. | the cro protein specified by bacteriophage lambda is a repressor essential for normal lytic growth of the virus, thus having a physiological role distinct from that of ci, the repressor that maintains lysogeny. we have purified a lambda-specific dna-binding protein with the requirements for synthesis and biochemical activities expected for cro protein from studies in vivo. as isolated, the protein appears to be a dimer of molecular weight approximately 18,000 with dna-binding properties that are ... | 1976 | 1065873 |
| transcription termination and late control in phage lambda. | a transcription termination site occurs between the promoter for late gene expression of bacteriophage lambda and the late genes themselves. it is proposed that the lambda q gene product controls late gene expression by over-coming this termination barrier. | 1975 | 1059112 |
| the site-specific deoxyribonuclease from bacillus pumilus (endonuclease r.bpu1387). | a new site-specific endonuclease (dnase) was isolated from the cells of bacillus pumilus ahu 1387 strain. this enzyme (endonuclease r.bpu 1387) introduced double-stranded scissions at unique sites on dna's of coli phage lambda, lambdadvl, coli phage t7, bacillus phage phi105c, bacillus phage sp10, and simian virus 40, in the presence of magnesium ion. the activity was stimulated by the presence of nacl. | 1976 | 1018024 |
| a complex control circuit. regulation of immunity in temperate bacteriophages. | temperate bacteriophages can display in a stable way two essentially different behaviours. in the immune state, a gene (ci) produces a repressor which prevents expression of all the other viral genes; in the non-immune state the typically viral functions are expressed. the choice between the two pathways and the establishment of one of them have much in common with cell determination and differentiation. this choice depends on a complex control system, in fact one of the most intricate nets of r ... | 1976 | 1009948 |
| [mapping of phage lambda dna using the antibiotic distamycin]. | | 1976 | 971663 |
| induction and mutagenesis of prophage lambda in escherichia coli k12 by metabolites of aflatoxin b1. | like most carcinogens, aflatoxin b1 must be activated by mammalian microsomal enzymes to give rise to coupounds active on bacteria. these compounds act as inducers of e. coli k12 (lambda) at a high efficiency, whereas unmodified aflatoxin b1 has no effect. moreover, metabolites of aflatoxin b1 have a mutagenic action on phage lambda, as shown by the appearance of clear plaque mutants. we propose the hypothesis that the same derivative is responsible for carcinogenesis of liver cells by aflatoxin ... | 1975 | 1095913 |
| physiological transition of a coliphage lambda dna replication. | the "rolling-circle" replicative intermediate (sigma-type molecules) which is normally produced in the late stage of coliphage lambda dna replication can be found during the first round of lambda dna replication if cells infected with lambda replication mutant ots28 are incubated at the nonpermissive temperature until the late stage of the latent period of lambda infection. after shifting to the permissive temperature, the vast majority of replicating forms are sigma-type rolling circle even dur ... | 1975 | 1096948 |
| genetic and physical studies of lambda transducing bacteriophage carrying the beta subunit gene of the escherichia coli ribonucleic acid polymerase. | the prophage lambdac1857 was inserted into the bfe gene located near rif (the structural gene for the beta subunit of deoxyribonucleic acid [dna]-dependent ribonucleic acid polymerase) on the escherichia coli chromosome. induced lysates (low-frequency transducing lysates) of such a lysogen contained defective lambda phage particles (lambdadrif+) that can specifically transduce the wild-type rif+ gene. upon transduction into a recipient strain carrying reca, heterogenotes harboring both the wild- ... | 1975 | 1097397 |
| bacteriophage lambda head morphogenesis: studies on the role of dna. | | 1975 | 1097706 |
| on the mechanism of production of tandem genetic duplications in phage lambda. | | 1975 | 1097713 |
| packaging of prophage and host dna by coliphage lambda. | | 1975 | 1097937 |
| determination of genes, restriction sites, and dna sequences surrounding the 6s rna template of bacteriophage lambda. | a major product of the transcription of bacteriophage lambda dna in vitro is the 6s rna. this article presents a detailed mapping of restriction endonuclease cleavage sites about the region of the 6s rna template within the lambda genome. restriction fragments defined by these sites have been used to localize the 6s rna template within the physical and genetic maps of the lambda genome. nucleotide sequence analysis of one of these fragments has largely confimed the nucleotide sequence of the 6s ... | 1975 | 1098044 |
| proposed mechanism of bacteriophage lambda induction: acquisition of binding sites for lambda repressor by dna of the host. | interference with the in vitro binding of lambda phage repressor to lambda operator dna was observed when escherichia coli dna containing the following lesions was present in the reaction mixture: (a) dna with single-strand breaks from pancreatic dnase (nicked dna); (b) dna isolated from thymine-straved cells; (c) dna from ultraviolet-treated cells; (d) dna of mitomycin-treated cells; and (e) dna from a temperature-sensitive ligase mutant after 1 hr at 42 degrees. normal e. coli dna did not inte ... | 1975 | 1098048 |
| strand breakage of coliphage lambda dna supercoils in infected lysogens. i. genetic and biochemical evidence for two types of nicking processes. | | 1975 | 1098274 |
| the kil gene of bacteriophage lambda. | | 1975 | 1098278 |
| host mutants resistant to phage lambda killing. | | 1975 | 1098279 |
| regulation of early protein synthesis in bacteriophage lambda. | | 1975 | 1098280 |
| isolation of specialized transducing bacteriophage lambda carrying genes of the l-arabinose operon of escherichia coli b/r. | a heat-inducible lysis-defective phage lambda (lambdaci857s7) has been integrated at multiple sites within the l-arabinose region (aracoibad) of a strain of escherichia coli k-12 deleted for the normal lambda attachment site (lambdaattdelta). the lambda phage has become integrated with opposite orientations at two different loci within the aratb gene and with the "normal" orientation (clockwise n-ra-j) at a single site in the arac gene. the burst size, spontaneous-curing frequencies, and number ... | 1975 | 1099071 |
| electron microscopic study of the repressor of bacteriophage lambda and its interaction with operator dna. | | 1975 | 1099211 |
| the nature and origin of a class of essential gene substitutions in bacteriophage lambda. | | 1975 | 1099781 |
| maltose transport in escherichia coli k-12: involvement of the bacteriophage lambda receptor. | mutants affected in lamb, the structural gene for phage lambda receptor, are unable to utilize maltose when it is present at low concentrations (less than or equal 10 mum). during growth in a chemostat at limiting maltose concentrations, the lamb mutants tested were selected against in the presence of the wild-type strain. transport studies demonstrate that most lamb mutants have deficient maltose transport capacities at low maltose concentrations. when antibodies against purified phage lambda r ... | 1975 | 1100596 |
| role of the receptor for bacteriophage lambda in the functioning of the maltose chemoreceptor of escherichia coli. | chemotaxis towards maltose is specifically defective in many strains of escherichia coli carrying mutations affecting lamb, the gene coding for the outer membrane receptor for bacteriophage lambda. however, with one exception, the most extreme effect of lamb mutants on the maltose response as determined in the capillary assay is a shift to higher sugar concentrations and a reduction in the number of bacteria accumulated to about 25% of the wild-type level. the severity of the taxis defect is str ... | 1975 | 1100597 |
| indirect mutagenesis in phage lambda by ultraviolet preirradiation of host bacteria. | | 1975 | 1100853 |
| extensive segments of the escherichia coli k12 chromosome in proteus mirabilis diploids. | various escherichia coli k12 hfr donors transfer at low frequency portions of the e. coli genome to proteus mirabilis. by remating such proteus hybrids with the same or a different e. coli hfr strain, other genetic characters could be added to yield diploid proteus hybrids which contained more than 30 percent of the e. coli genome. the extent of the e. coli genetic material in these unstable proteus diploid hybrids included segments with the following selected markers: gal, lac, ara, mel, mtl, a ... | 1975 | 1101034 |
| [e. coli mutanic produced by the insertion of bacteriophage lambda dna (author's transl)]. | | 1975 | 1101309 |
| synthesis and degradation of early mrna in lambda phage. | using two different escherichia coli mutants defective in elongation factors efg and efts required for peptide synthesis, lambda phage with or without a tof mutation was analysed for synthesis of early mrna by dna-rna hybridization technique. (1) in cp78g carrying temperature-sensitive elongation factor g, shift-up to high temperature (41 degrees c) in the middle of phage infection did not affect early mrna synthesis with lambdatof+ phage but did inhibit it with lambdatof- phage. (2) in hak88 ca ... | 1975 | 1101966 |
| tandem genetic duplications in phage lambda. iii. the frequency of duplication mutants in two derivatives of phage lambda is independent of known recombination systems. | | 1975 | 1102698 |
| processing of bacteriophage lambda dna during its assembly into heads. | | 1975 | 1102699 |
| dna packaging steps in bacteriophage lambda head assembly. | | 1975 | 1102700 |
| assembly of bacteriophage lambda heads: protein processing and its genetic control in petit lambda assembly. | | 1975 | 1102701 |
| studies on the cleavage of bacteriophage lambda dna with ecori restriction endonuclease. | | 1975 | 1102702 |
| replication of bacteriophage lambda dna: in vivo studies of the interaction between the viral gamma protein and the host recbc dnaase. | | 1975 | 1102714 |
| further structural and functional analogies between the repressor regions of phages p22 and lambda. | mutants of p22 which have been located in the c2 repressor gene were examined. the most rightward "c2 mutation" was found to define a site that is necessary only for the establishment and not for the maintenance of repressor synthesis. we conclude that this site c27 is an analog of cy mutants in phage lambda which define a promotor for repression establishment (pre). the k5 mutation of p22 maps between c27 and all other c2 mutants. examination of its biological behavior and direct measurement of ... | 1975 | 1102926 |
| visualization of a novel junction in bacteriophage lambda dna. | at early times after infection of a reca derivative of escherichia coli with lambdab221c126red270a42 phage, a low but significant proportion of intracellular lambda molecules show a novel junction. these junctions are also present, although in reduced numbers, in a lysate obtained at late times after infection of a reca+ host with lambdaciiciii phage. fine structure and denaturation mapping analyses showed that these junctions occur at homologous positions and that they are compatible with the o ... | 1975 | 1103134 |
| in vitro construction of bacteriophage lambda carrying segments of the escherichia coli chromosome: selection of hybrids containing the gene for dna ligase. | dna from lambdagt-lambdab bacteriophage was cleaved with ecori endonuclease and fragments from ecori-digested e. coli dna were inserted. this dna was used to infect e. coli, and phages containing the gene for dna ligase were isolated by genetic selection. two different hybrids were found with the same e. coli segment inserted in opposite orientations. both hybrids produced similar levels of ligase as measured in crude extracts of infected cells. | 1975 | 1103146 |
| characterization of a novel, low-molecular-weight dna-binding protein from escherichia coli. | a low-molecular-weight (7000), heat-stable protein--hu--that stimulates transcription of bacteriophage lambda dna by e. coli rna polymerase was purified from e. coli extracts using affinity chromatography on dna-cellulose. hu binds to native dna, resulting in an apparent thickening of the dna chains as revealed by electron microscopy. contrary to dna unwinding proteins, it causes no destabilization of the double helix. hu differs from previously described transcription factors (h1, d, etc.) and ... | 1975 | 1103148 |
| bacteriophage lambda induction causes increased production of e. coli lysine transfer rna. | | 1975 | 1103738 |
| recovery of phage lambda from ultraviolet damage. | recovery of phage lambda from ultraviolet damage can occur, in the dark, through three types of repair processes as defined by microbiological tests: (1) host-cell reactivation, (2) prophage reactivation, and (3) uv reactivation. this paper reviews the properties of the three repair processes, analyzes their dependence on the functioning of bacterial and phase genes, and discusses their relationship. progress in the understanding of the molecular mechanisms underlying the three repair processes ... | 1975 | 1103822 |
| deoxyribonucleic acid modification by intermediate-type modification mutants of escherichia coli k-12 and b. | the modification of bacteriophages grown on r-m+/- restriction and modification mutants of escherichia coli k-12 or b appears to be related to the number of restriction-specific sites in the viral genome. bacteriophage fd and its mutant u1 fd, which carry two and one b-specific sites, respectively, are not modified in vivo by rb-mb+/- mutant strains. in vitro treatment of fd rf-b+/- deoxyribonucleic acid (dna) or u1 fd rf-b+/- dna by endo r-eco b results in cleavage of the substrate dna. lambda ... | 1975 | 1104586 |
| excision of bacteriophage lambda from a site in the arabinose b gene. | a lambda lysogen with the prophage inserted into the arabinose b gene of escherichia coli strain k-12 has been prepared. induction of the phage from this lysogen yields viable phage at a frequency 4 x 10(-6) that found for induction of lysogens with phage inserted at the normal attachment site. over 30% of the phage particles induced from the insertion in ara are arabinose-transducing phage. the excision end points of 62 independently isolated, nondefective arac-transducing phage containing less ... | 1975 | 1104587 |
| petit lambda, a family of particles from coliphage lambda infected cells. | | 1975 | 1104865 |
| phage lambda receptor chromosomes for dna fragments made with restriction endonuclease iii of haemophilus influenzae and restriction endonuclease i of escherichia coli. | | 1975 | 1104875 |
| the sensitivity of bacteriophage lambda dna to restriction endonuclease rii. | | 1975 | 1104876 |
| induction of error-prone repair as a consequence of dna ligase deficiency in escherichia coli. | dna ligase deficiency is shown to induce generalized mutator activity in e. coli. this mutator activity is unaffected by 3 mug/ml of chloramphenicol but is abolished both in lig-reca double mutants and by incubation with 20 mug/ml of chloramphenicol. dna ligase deficiency is also shown to reactivate ultraviolet light-irradiated phage lambda and t7 and to increase both spontaneous and ultraviolet light-induced mutagenesis in phage lambda, all of which are abolished in lig-reca strains. interactio ... | 1975 | 1105587 |
| an early regulatory gene of salmonella phage p22 analogous to gene n of coliphage lambda. | | 1975 | 1105960 |
| [isolation of a protein factor increasing the infectivity of bacteriophage lambda dna]. | | 1975 | 1106973 |
| letter: the dna synthesis of u.v.-irradiated lambda phage in a u.v.-sensitive host bacterium. | | 1975 | 1107241 |
| reversible interaction between coliphage lambda and its receptor protein. | | 1975 | 1107562 |
| prophage induction and cell division in e. coli. iii. mutations sfia and sfib restore division in tif and lon strains and permit the expression of mutator properties of tif. | in e. coli k12, cell filamentation promoted by tif is enhanced by the lon mutation; in contrast, prophage induction and repair of uv-irradiated phage lambda, also promoted by tif, are not affected by lon. from a tif lon double mutant, "revertants" having recovered the ability to divide at 41 degrees were isolated, among which most (95%) had also lost their lon filamentous phenotype after ultraviolet (uv) irradiation. from these 95% of revertants: (1) 94% are suppressed for the whole tif phenotyp ... | 1975 | 1107802 |
| genetic consequences of transfection with heterduplex bacteriophage lambda dna. | the role of rectification of heteroduplex heterozygotes in the formation of recombinant genotypes involving closely linked markers has been examined. heteroduplex molecules of bacteriophage lambda dna, heterozygous at several alleles, have been constructed and the genetic composition of phage present in infective centers derived by transfection with such molecules has been determined. allele loss and concomitant recombinant formation is frequent, and appears to reflect marker specificity as well ... | 1975 | 1107809 |
| effects of bacteriophage t4-induced modification of escherichia coli rna polymerase on gene expression in vitro. | after t4 bacteriophage infection of e. coli a complex series of events take place in the bacterium, including gross inhibition of host transcription and discrete changes in the classes of the genes of t4 that are transcribed. accompanying these changes in the pattern of transcription one finds t4-induced changes in the rna polymerase (ec 2.7.7.6; nucleosidetriphosphate:rna nucleotidyltransferase). the effects of modified polymerase on transcription can be advantageously analyzed in a dna-directe ... | 1975 | 1108008 |
| visualization of prokaryotic dna in a regularly condensed chromatin-like fiber. | electron microscopy of disrupted escherichia coli cells under certain conditions revealed loops of a fiber 120 a in diameter which were attached to the cell envelope and showed a 130 a repeating beaded substructure. these fibers were detected only when the cells were lysed in 0.15 m nacl solutions directly on the electron microscope supporting films and if the dehydration steps began within 2 min of lysis. under these conditions examination of cells lysogenic for phage lambda after superinfectio ... | 1976 | 1108025 |
| phage lambda dna injection into escherichia coli pel- mutants is restored by mutations in phage genes v or h. | | 1976 | 1108413 |
| inhibtory effect of colicin e2 on transport systems of escherichia coli in the presence of the rex gene of lambda prophage. | purified colicin e(2) was found to cause marked inhibition of the permeation rate of o-nitrophenyl-galactoside (onpg) in several lambda-lysogenic strains of escherichia coli in the presence of chloramphenicol to prevent prophage induction. the inhibitory effect of colicin e(2) on transport systems was analyzed with cells of e. coli cp78(lambda). the dose of colicin e(2) for the half-maximum inhibition of the onpg-permeation rate was about 9 molecules of the colicin per bacterium under the aerobi ... | 1975 | 1108779 |
| preparation and photochemical properties of strand-specific 5-bromouracil-substituted lambda phage. | | 1975 | 1110980 |
| morphogenesis of the tail of bacteriophage lambda. | | 1975 | 1111212 |
| [isolation of a dna fragment containing phage lambda repressor gene]. | | 1975 | 1112180 |
| functional inactivation of bacteriophage lambda morphogenetic gene in rna. | | 1975 | 1113861 |
| positive and negative regulation by the cii and ciii gene products of bacteriophage lambda. | | 1975 | 1114699 |
| amber red- mutants of phage lambda. | | 1975 | 1114701 |
| isolation of nonsense mutants in the morphogenetic region of the bacteriophage lambda chromosome. | | 1975 | 1114710 |
| sequence of the or operator of phage lambda. | a sequence of 79 nucleotides from the lambda or operator is obtained by primed transcription of repressor protected dna fragments. the sequence contains the primary repressor binding site plus partial duplications which can be interpreted as secondary repressor binding sites. | 1975 | 1117995 |
| sequence of the pr promoter of phage lambda. | the rna polymerase binding site from the lambda pr promoter was isolated and sequenced. this dna fragment contains the transcription initiation site and shares 25 nucleotides with or. the sequence preceding the initiation site suggests that the promoter recognition site is not identical with the tight binding and initiation site. | 1975 | 1117996 |
| detection by electron microscopy of photo-induced denaturation in lambda dna. | we have used an electron microscope to study localized denatured regions in ultraviolet-irradiated dna. dna from bacteriophage lambda was uv-irradiated and then prepared for electron microscopy after fixing in buffered (ph 9.5) formaldehyde solutions at 25 degrees c. the denatured regions observed corresponded to those described by inman and schnös (1) who used alkaline denaturation to preferentially destroy thymine-adenine base pairing. in uv-irradiated dna, pairs of neighboring thymine residue ... | 1975 | 1121421 |
| regulation of early gene expression in bacteriophage lambda: effect of tof mutation on strand-specific transcriptions. | | 1975 | 1129947 |
| genetic analysis of the tof gene in the bacteriophage lambda genome. | | 1975 | 1129948 |
| specific hydrolysis of the cohesive ends of bacteriophage lambda dna by three single strand-specific nucleases. | procedures have been worked out for aspergillus nuclease s1 and mung been nuclease to quantitatively cleave off both of the 12-nucleotide long, single-stranded cohesive ends of lambdadna. this cleavage is indicated by the almost complete elimination of the repair incorporation of radioactive nucleotides by dna polymerase into the digested dna. with s1 nuclease, cleavage was complete at 10 degrees as well as at 30 degrees. under the conditions for quantitative cleavage of the single-stranded regi ... | 1975 | 1141222 |