| studies on the biological role of dna methylation: iii role in excision of one-genome long single-stranded phi x 174 dna. | accumulation of replicative intermediates of the bacteriophage phi x174 was observed in e. coli c infected cells when phage dna methylation has been inhibited by nicotinamide or when cells were infected with a temperature-sensitive mutant in gene a. analysis of the accumulating replicative intermediates by electron microscopy revealed that these molecules are composed of double-stranded dna rings with multiple-genome length single-stranded "tails". these results suggest that the single 5-methylc ... | 1977 | 144900 |
| bacteriophage phix174: gene a overlaps gene b. | the map position of several phix174 mutations in the genes a and b was determined by marker rescue with dna fragments produced by the restriction enzymes hha i, hindii, hae iii, and alu i. all the gene b mutants were found to be located within gene a. genetic complementation and analysis of phage-specific protein synthesis show that, under restrictive conditions, nonsense mutants in gene a do not block the synthesis and activity of the b protein and nonsense mutants in gene b do not affect the g ... | 1977 | 267943 |
| construction and characterization of an escherichia coli plasmid bearing a functional gene g of bacteriophage phix174. | in order to study the mutagenic effects of site-specific, covalent modifications of biologically active dna, we need host cells that are permissive for any type of mutation that might be produced in vivo from the modified dna. specifically, we require a general, in vivo complementation system for the bacteriophage phix174 gene g, an essential gene that we have chosen for our initial studies of chemical mutagenesis. toward this end, we have constructed a plasmid (pphixg) that carries a functional ... | 1978 | 273240 |
| discontinuous replication of replicative form dna from bacteriophage phix174. | bacteriophage phix174 dna has been labeled with short pulses of [3h]thymidine during synthesis of replicative form molecules in infected escherichia coli hf4704 cells. the replicating phix174 dna was isolated and analyzed by sedimentation in an alkaline sucrose gradient. during a brief pulse (5 sec at 30 degrees), the radioactivity incorporated into the complementary strand was found in chains much shorter than one genome length. of the radioactivity incorporated into the viral strand, two-third ... | 1977 | 268627 |
| studies on nucleic acid reassociation kinetics: retarded rate of hybridization of rna with excess dna. | the rate of reaction of excess double-stranded bacteriophage phix174 and plasmid rsf2124 dna drivers with enzymatically synthesized asymmetric rna tracers was measured. other reactions were carried out with excess escherichia coli dna and e. coli rna labeled in vivo. rna and dna fragment lengths were held approximately equal. for each case it was shown that in dna excess the rate constant for rna-dna hybridization is 3- to 4.5-fold lower than that of the renaturation rate constant for the driver ... | 1977 | 267925 |
| studies on nucleic acid reassociation kinetics: rate of hybridization of excess rna with dna, compared to the rate of dna renaturation. | the rate of reaction of double-stranded replicative form (rf) [3h]dna of bacteriophage phix174 with excess (+)strand dna and (+)strand rna was measured by standard methods of hydroxyapatite chromatography. the reactions follow pseudo-first-order kinetics and the observed rate constant for the rna-dna reaction differs less than 25% from that of the dna-dna reaction. the pseudo-first-order rate constants are close to the value predicted on the basis of the second-order rate constant measured in th ... | 1977 | 265546 |
| molecular mechanisms of induced mutagenesis. replication in vivo of bacteriophage phix174 single-stranded, ultraviolet light-irradiated dna in intact and irradiated host cells. | | 1977 | 340704 |
| mechanisms of inactivation of bacteriophage phix174 and its dna in aerosols by ozone and ozonized cyclohexene. | the mechanisms of inactivation of aerosolized bacteriophage phix174 in atmospheres containing ozone, cyclohexene, or ozonized cyclohexene were studied by using 32p-labelled phage. the inactivation of the aerosolized phage in clear air or in air containing cyclohexene is due to damage of the protein coat since the deoxyribonucleic acid (dna) extracted from the inactivated phage retains its biological activity. inactivation of the phage in air containing ozonized cyclohexene is due both to protein ... | 1977 | 265342 |
| survival of aerosolized bacteriophage phi x174 in air containing ozone--olefin mixtures. | the effects of ozone and ozonized olefins on aerosol survival of bacteriophage phix174 were studied. the ozone concentrations used were between 0 and 110 parts/10(9), giving decay rates up to 0-03 min-1. the olefins used were trans-2-butene and cyclohexene in concentrations of 500 parts/10(9) and 2-4 parts/10(6), respectively. olefins alone have no effect, whereas in combination with ozone, decay rates of 0-1 min-1 and higher were obtained. the results are discussed in relation to the viricidal ... | 1977 | 265341 |
| bacteriophage phi x174 rf dna replication in vivo. a study by electron microscopy. | | 1979 | 231111 |
| a general priming system employing only dnab protein and primase for dna replication. | priming of phage phi x174 dna synthesis is effected simply by dnab protein and primase when the dna is not coated by single-strand binding protein (ssb). the five prepriming proteins (n,n',n'',i, and dnac protein) required for priming a ssb-coated phi x174 dna circle are dispensable. the dnab protein-primase priming system is also active on uncoated phage g4 and m13 dnas and on poly(dt). multiple rna primers, 10--60 nucleotides long, are transcribed with patterns distinctive for each dna templat ... | 1979 | 228295 |
| influence of the dna structure on the free radical induction due to proflavine and light treatment. | induction of peroxide free radicals (detected by electron paramagnetic resonance at 77 k) due to the photodynamic activity of proflavine was measured on bacteriophage phi x174 dna either single-stranded (ss) as isolated from the virion, or double-stranded supercoiled (rfi) as isolated from the infected bacteria. comparison was made with calf thymus dna photosensitization. in order to use equivalent dna-proflavine complexes, binding of the dye to the three dna's was first determined under those c ... | 1979 | 224407 |
| free radical induction in bacteriophage phix174 dna after exposure to proflavine and visible light. | | 1977 | 195615 |
| purified dnas are transcribed after microinjection into xenopus oocytes. | the possibility of using dna-injected xenopus laevis oocytes and eggs for studying the control of transcription in eukaryotes has been investigated. when purified dna of simian virus 40 (sv40) is injected into xenopus laevis oocytes, tritiated rna precursors are incorporated into dnase-i-resistant, rnase-a- and alkali-sensitive material that hybridizes specifically to sv40 dna. this viral transcription continues for at least 5 days and occurs only when the injected dna is directed to the nucleus ... | 1977 | 193103 |
| influence of sos repair on the specificity of radiation mutagenesis in bacteriophage phix174. | the ochre mutant oc9 of bacteriophage phix174 was irradiated with gamma-rays and the revertants were assayed on unirradiated and uv-irradiated host bacteria carrying an amber suppressor. the yield of revertants (amber + wild type) was higher on uv-irradiated than on unirradiated bacteria, showing that gamma-irradiated phix174 was subjected to w-mutagenesis. for oc9 gamma-irradiated in the presence of oxygen the fraction of amber mutants among the revertants was lower when mutants were scored on ... | 1979 | 160972 |
| cleavage of single-stranded dna by the a and a* proteins of bacteriophage phi x174. | the purified a protein and a* protein of bacteriophage phi x174 have been tested for endonuclease activity on single stranded viral phi x174 dna. the a protein (55.000 daltons) nicks single-stranded dna in the same way and at the same place as it does superhelical rfi dna, at the origin of dna replication. the a* protein (37.000 daltons) can cleave the single-stranded viral dna at many different sites. it has however a strong preference for the origin of replication. both proteins generate 3'oh ... | 1979 | 160544 |
| production of breaks in single- and double-stranded forms of bacteriophage phi x174 dna by proflavine and light treatment. | | 1979 | 160046 |
| in vivo methylation of bacteriophage phi x174 dna. | a mutant (designated mec(-)) has been isolated from escherichia coli c which has lost dna-cytosine methylase activity and the ability to protect phage lambda against in vivo restriction by the rii endonuclease. this situation is analogous to that observed with an e. coli k-12 mec(-) mutant; thus, the e. coli c methylase appears to have overlapping sequence specificity with the k-12 and rii enzymes; (the latter methylases have been shown previously to recognize the same sequence). covalently clos ... | 1979 | 159962 |
| yield of ultraviolet light-induced pyrimidine dimers in the dna of bacteriophage phix174. | | 1977 | 599564 |
| fidelity of replication of phage phi x174 dna by dna polymerase iii holoenzyme: spontaneous mutation by misincorporation. | dna from phi x174 is replicated in vitro with a fidelity similar to that found genetically. a mutation of tag leads to tgg may be induced, however, by varying the concentrations of deoxynucleoside triphosphates, with a frequency proportional to [dgtp]2/[datp]. this complex concentration dependence is consistent with the active participation of a proofreading mechanism that hydrolytically excises mismatched base pairs as they are formed. a simple kinetic analysis predicts that the frequency of mi ... | 1979 | 159450 |
| isolation and identification of bacteriophage phi x174 prohead. | the morphogenesis of bacteriophage phi x174 has been investigated by using an in vitro dna synthesizing system. an extract of a b-mutant-infected cell is capable of synthesizing infectious phage in vitro when the b gene function is provided by the addition of an ammonium sulfate fraction of a c-mutant-infected-cell extract. this fraction contains the omega complex, a complex of phage-coded proteins with s = 108; the b-mutant extract does not. the purified omega complex, isolated from the c-mutan ... | 1979 | 159449 |
| electrophoretic characterization of intracellular forms of bacteriophage phi x174 dna: identification of novel intermediate of altered superhelix density. | the replication cycle of bacteriophage phi x174 dna has been analyzed by agarose gel electrophoresis. the electrophoretic behavior of the predominant species of parental and progeny dna molecules formed between 5 and40 min after infection was deduced and quantitated. migration through 1.4% agarose at 5 and 10 v/cm resolved all known viral dna species as well as fragments of host chromosomal dna. among parental replicative form(rf) molecules synthesized, 1 to 3% were full length linear duplexes ( ... | 1979 | 159364 |
| alkali-labile sites and post-irradiation effects in gamma-irradiated biologically active double-stranded dna in aqueous solution. | gamma-irradiation of double-stranded rf-dna of bacteriophage phi x174 in aqueous solution in the presence of oxygen produces at least one type of alkali-labile site. it is lethal and gives rise to breaks by alkali and is identical with the damage which becomes manifest by post-irradiation heat treatment. the effect of alkali is dependent on temperature. furthermore, the excision repair system is not involved in eliminating lethal nucleotide damage in rfi-dna. | 1979 | 159268 |
| defined transversion mutations at a specific position in dna using synthetic oligodeoxyribonucleotides as mutagens. | the oligodeoxyribonucleotides, pcccagcctcaa, which is complementary to nucleotides 5274--4284 of bacteriophage phi x174 viral dna , and pcccagcctaaa, which corresponds to the same sequence with a c leads to a change at the ninth nucleotide, were synthesized enzymatically. the second of these oligonucleotides was used as a primer for e. coli dna polymerase i, from which the 5'-exonculease has been removed by proteolysis (klenow enzyme), on wild-type phi x174 viral dna template. after ligation, th ... | 1979 | 158749 |
| role of polymeric forms of the bacteriophage phi x174 coded gene a protein in phi xrfi dna cleavage. | gene a of the phi x174 genome codes for two proteins, a and a* (linney, e.a., and hayashi, m.n. (1973) nature new biol. 245, 6-8) of molecular weights 60,000 and 35,000, respectively. the phi x a* protein is formed from a natural internal initiator site within the a gene cistron while the phi x a protein is the product of the entire a gene. these two proteins have been purified to homogeneity as judged by sodium dodecyl sulfate polyacrylamide gel electrophoresis. previous studies have shown that ... | 1979 | 158588 |
| a mechanism of duplex dna replication revealed by enzymatic studies of phage phi x174: catalytic strand separation in advance of replication. | the enzyme system for duplicating the duplex, circular dna of phage phi x174 (replicative form) in stage ii of the replicative life cycle was shown to proceed in two steps: synthesis of the viral (+) strand ]stage ii(+)], followed by synthesis of the complementary (-) strand ]stage ii(-)] [eisenberg et al. (1976) proc. natl. acad. sci. usa 73, 3151-3155]. novel features of the mechanism of the stage ii(+) reaction have now been observed. the product, synthesized in extensive net quantities, is a ... | 1977 | 138139 |
| studies on the biological role of dna methylation. ii. role of phix174 dna methylation in the process of viral progeny dna synthesis. | in vivo inhibition of bacteriophage phix174 dna methylation by nicotinamide resulted in the accumulation of replicative intermediates with multiple-genome length single-stranded "tails". these abnormal replicative intermediates could not be chased into viral single-stranded circular dna. the effect of nicotinamide on phage maturation and accumulation of abnormal replicative intermediates could be reversed by washing out the inhibitor. the results suggest that the single methyl group present in t ... | 1976 | 136644 |
| some sequence similarities among cloned mouse dna segments that code for lambda and kappa light chains of immunoglobulins. | a comparison between the cloned mouse dna segments that were found to code for the lambda and kappa light chains of immunoglobulins established that there were seven short nucleotide sequences, two of which matched 6 out of 7, two 7 out of 8, two 8 out of 9, and one 9 out of 10 bases; these sequences were located either at homologous amino acid positions or at positions displaced by four amino acids or less. they all occurred in the framework regions (frs), five next to the complementarity-deter ... | 1979 | 116235 |
| r-loops in bacteriophage phix174 rf dna. | | 1978 | 731691 |
| the nucleotide sequence of bacteriophage phix174. | | 1978 | 731693 |
| nucleotide sequence of the f protein coding region of bacteriophage phix174 and the amino acid sequence of its product. | | 1978 | 731694 |
| genetic control of the immune response to bacteriophage phix174 in inbred mice. | | 1978 | 105946 |
| nucleotide sequences of the separate origins of synthesis of bacteriophage g4 viral and complementary dna strands. | bacteriophage g4 has physically separated origins of synthesis of its viral and complementary dna strands. chain termination and "plus and minus" dna sequencing methods have been used to obtain the nucleotide sequence of these two origins. the unique origin at which the complementary dna strand is initiated has located in the untranslated region between genes f and g. this sequence, which has considerable secondary structure, contains a stretch which is complementary to the rna primer that is ob ... | 1978 | 274698 |
| efficient correction of a mutation by use of chemically synthesized dna. | the mutated base in the am3 lysis-defective mutant of the bacteriophage phix174 has been corrected by a combined in vitro enzymatic dna synthesis and in vivo replication of the heteroduplex product. chemically synthesized oligodeoxyribonucleotides carrying the wild-type sequence have been used to prime dna synthesis with am3 phix174 dna serving as a template. the resultant semisynthetic heteroduplex composed of an am3(+) strand and a wild-type (-) strand, with one mismatched base pair at positio ... | 1978 | 279913 |
| dna sequencing and melting curve. | the dependence of dna absorbance (for light at about 260 nm) on temperature is related to a specific dna sequence structure in the vicinity of dna thermal denaturation (the so-called dna melting or coiling). a straightforward analysis of the experimental dna melting curve allows us to determine the lengths, the a+t content, and the location in dna of certain domains. in the case of a specific dna fragmentation, the order of fragments in dna can be learned from this analysis, nondestructively and ... | 1979 | 284324 |
| bacteriophage phix174 growth in an escherichia coli dnaits mutant, ks810. | a bacteriophage phix174-sensitive escherichia coli dnaits mutant, ks810, was constructed and growth of phix174 in the cells was investigated. phix174 and phix174am3trd could grow normally at 43 degrees c as well as 27 degrees c, therefore we conclude that the growth of bacteriophage phix174 is not dependent upon the host dnai gene product. | 1978 | 341986 |
| dna synthesis in escherichia coli cells infected with gene h mutants of bacteriophage phi x174. | escherichia coli cells infected with gene h mutants of bacteriophage phi x174 produce two types of particles. the 110s particles contain single-stranded circular dna; the 110s particles are not infectious, although their dna is infectious for e. coli spheroplasts. the second type of particles, 70s particles, contain a fragment of single-stranded dna ranging from 0.2 to 0.5 genome in length. this fragment dna anneals only to restriction enzyme fragments of replicative-form dna from the portion of ... | 1979 | 376874 |
| a new locus of escherichia coli that determines sensitivity to bacteriophage phi x174. | a new gene designated phxb, necessary for adsorption of phix174 to the cell surface of escherichia coli, is located between gal and arog on the e. coli chromosome. | 1979 | 378929 |
| growth and dna synthesis of bacteriophage phi x174 in a dnap mutant of escherichia coli. | phi x174am3trd, a temperature-resistant mutant of bacteriophage phi x174am3, exhibited a reduced ability to grow in a dnap mutant, escherichia coli km107, at the restrictive temperature (43 degrees c). under conditions at which the dnap gene function was inactivated, the amount and the rate of phi x174am3trd dna synthesis were reduced. the efficiency of phage attachment to e. coli km107 at 43 degrees c was the same as to the parental strain, e. coli kd4301, but phage eclipse and phage dna penetr ... | 1979 | 384019 |
| heterologous transfection with bacteriophage phix174 dna. unusual heterogeneous products. | hydroxylamine-resistant infectious materials (harim) synthesized in natural non-host and progeny phage low productive bacterial spheroplasts upon transfection with bacteriophage phix174 dna were found to be unusually heterogeneous in their forms. using pseudomonas aeruginosa as a source of harim, it was shown that they have the following unusual features. (1) almost all of the harim are denser than normal single-stranded (ss)- and double-stranded replicative form (rf)-dnas of phix174 found usual ... | 1977 | 402155 |
| heterologous transfection with bacteriophage phix174 dna: and improved system. | a highly efficient and much more reproducible system for the heterologous transfection of several kinds of gram-negative bacterial spheroplasts with bacteriophage phix174 dna was established. by mild washing of the speroplasts, the efficiency of transfection of all non-host heterologous bacterial species tested increased one or more orders of magnitude in producing the progeny phages and/or the infectious intermediates. using the improved heterologous transfection systems, it has become clearer ... | 1978 | 418813 |
| the in vitro transcription units of bacteriophage phix174. iii. initiation with specific 5' end oligonucleotides of in vitro phix174 rna. | | 1976 | 781284 |
| recombination of bacteriophage phi x174 by the red function of bacteriophage lambda. | recombination of bacteriophage phi x174 was effectively promoted when the red function of lambda was supplied by either co-infection with lambda or induction of lambda lysogens. mutations in red alpha and red beta genes of lambda abolished recombination nearly completely, whereas a mutation in gam gene reduced it only slightly. the red-promoted recombination of phi x174 occurred in reca, recb, and pola mutants as well as in wild-type strains of escherichia coli. it was further stimulated when ph ... | 1979 | 430603 |
| construction of a site-specific, deletion-frameshift mutation in an essential gene of bacteriophage phix174. | by in vitro methods, we have deleted 80 nucleotides from a preselected site in the coding sequence of gene g of bacteriophage phix174. this mutant (gdelta/fs zh1) also carries a--2 frameshift. the mutation is lethal, but mutant virus can be stably maintained on host strains bearing plasmids carrying phix gene g. | 1979 | 431717 |
| functional relationship between bacteriophages g4 and phi x174. | mutants of bacteriophage g4 were isolated and characterized, and their mutations were mapped. they constitute six different genes, namely, a, b, e, f, g, and h. the functional relationship with bacteriophage phi x174 was determined by complementation experiments using amber mutants of phi x and amber mutants of g4. bacteriophage phi x was able to use the products of g4 genes e, f, g, and h. in bacteriophage g4, however, only the phi x gene h product was functional. | 1979 | 480475 |
| transcription by escherichia coli rna polymerase of a single-stranded fragment by bacteriophage phix174 dna 48 residues in length. | | 1975 | 806693 |
| the sequence of a region of bacteriophage phix174 dna coding for parts of genes a and b. | | 1977 | 592379 |
| proflavine mediated photoinactivation of bacteriophage phix174 and its isolated dna: effects of agents modifying various photochemical pathways. | | 1977 | 594173 |
| nucleotide sequence of the origin of replication in bacteriophage phix174 rf dna. | the gene a protein of bacteriophage phix174 has been used in vitro to convert phix rfi dna into the relaxed rfii form by nicking the viral strand. the nucleotide sequence at the 3' end of the nick has been determined as -- t g c t c c c c c a a c t t goh. this sequence gives the exact position of the origin of phix rf dna replication. | 1978 | 628424 |
| potential for variability through multiple gene products of bacteriophage phix174. | the small single-stranded dna phages phix174 and s13 produce multiple products of certain phage genes, as observed by electrophoresis on sds-polyacrylamide slab gels. two a protein products, two a products and four g products are observed. the multiple gene products may arise from multiple sites for initiation or termination of translation, or by protein modification. some of the variant products may provide a substitute for heterozygosity without a concomitant increase in the size of the genome ... | 1978 | 661992 |
| mutagenesis at a specific position in a dna sequence. | predefined changes in a known dna sequence were introduced by a general method. oligodeoxyribonucleotides complementary to positions 582 to 593 of the viral dna strand of the bacteriophage phix174 am3 mutant (pgtatcctacaaa), and to the wild type sequence in this region (pgtatcctacaaa), were synthesized and used as specific mutagens. each of these oligonucleotides was incorporated into a complete circular complementary strand when used as primer on a genetically heterologous viral strand template ... | 1978 | 681366 |
| studies on sheep kidney nuclease. ii. limited digestion of phix174 single-strand dna. | single strand dna of bacteriophage phix174 was digested by sheep kidney nuclease (nuclease sk) at 37 degrees c for 2-6 h and the digests were examined by 2.5% polyacrylamide gel electrophoresis. on this electrophoresis five bands were detected corresponding to the dna fragments by scanning the gel at 260 nm. after these dna fragments from the gel with the electrode buffer used for the electrophoresis, the molecular weights of fragments i, ii, iii, iv and v were determined by sucrose density grad ... | 1978 | 698232 |
| evolution of bacteriophage phi x174. iv. restriction enzyme cleavage map of st-1. | the st-1 genome is about 6,050 base pairs in size, approximately 10% larger than phix174 (5,375 base pairs). the dna fragments obtained by hincii, haeiii, and ecori digestion were ordered and aligned into a colinear map, and the single bgli cleavage site was located. | 1978 | 702640 |
| identification of lysis protein e of bacteriophage phix174. | the product of gene e, the lysis gene of phix174, has been identified as a distinct band in a sodium dodecyl sulfate-gel electropherogram. the position of the band is consistent with the molecular weight of 10,589 calculated from the nucleotide sequence of the gene. the band is eliminated by a nonsense mutation in gene e. it is estimated that roughly 100 to 300 molecules of e protein are made in an infected cell; this appears to be less than one-tenth the amount of protein made by gene d, in whi ... | 1978 | 702655 |
| nucleotide sequence of bacteriophage g4 dna. | the 5,577 nucleotide long sequence of bacteriophage g4 dna has been determined using the 'plus and minus' and chain termination methods of dna sequencing. this sequence has been compared with that of the closely related bacteriophage phix174 (refs 1, 55). in the coding regions there is an average of 33.1% nucleotide sequence differences between the two genomes, but the distribution of these changes is not random and the sequence of some genes is more conserved than others. there is less sequence ... | 1978 | 714153 |
| direct determination of dna nucleotide sequences. structure of large specific fragments of bacteriophage phix174 dna. | | 1976 | 1003475 |
| nucleotide sequence of the j gene and surrounding untranslated regions of phage g4 dna: comparison with phage phix174. | a 290 nucleotide long region of the bacteriophage g4 genome including the end of the overlapping genes d and e, the entire gene j and the untranslated region between genes j and f has been sequenced and compared with the same region in bacteriophage phix174. deletions, insertions, duplications and single base changes in g4 relative to phix174 have resulted in the following changes: the loss of the phix174 overlapping gene dtermination and gene j initiation codons, resulting in their separation b ... | 1978 | 728985 |
| bacteriophage phix174 rf dna replication in vivo: a biochemical study. | | 1978 | 731690 |
| isolation of an intermediate which precedes dnag rna polymerase participation in enzymatic replication of bacteriophage phi x174 dna. | conversion of phi x174 single-stranded dna to the duplex replicative form (rf) in vitro requires at least 10 purified proteins. three stages - strand initiation, elongation, and termination - comprise this conversion. we now identify a separate stage in strand initiation which precedes dnag rna polymerase participation. incubation of five proteins - protein i, protein n, dna unwinding protein, dnab protein, and dnac protein - with atp and phi x174 dna forms an intermediate which enables subseque ... | 1976 | 768984 |
| bacteriophage phix174 dna synthesis in a replication-deficient host: determination of the origin of phix dna replication. | | 1976 | 775113 |
| bacteriophage phix174 single-stranded viral dna synthesis in temperature-sensitive dnab and dna c mutants of escherichia coli. | we asked if phix174 single-stranded dna synthesis could reinitiate at the nonpermissive temperature in dnab and dnac temperature-sensitive host mutants. the rates of single-stranded dna synthesis were measured after the removal of chlorampheicol that had been added at various times after infection to specifically stop this stage of phix174 dna synthesis. reinitiation was not defective in either mutant host. our data suggested that the reinitiation of the single-stranded stage of phix174 dna synt ... | 1976 | 775125 |
| dna synthesis in vitro dependent upon phix174 replicative form i dna. | extracts of escherichia coli strains infected with bacteriophage phix174 catalyze dna synthesis dependent on double-stranded, circular phix174 replicative form i (phix rfi) by a semiconservative process. the reaction required mg++, atp, all four dntp, and exogenous phix rfi dna as template and yielded phix rfi and phix rfii. the reaction was inhibited by nalidixic acid and novobiocin but not by rifampicin. dna synthesis required the phix174 gene a product and e. coli gene products dnab, dnac(d), ... | 1976 | 778850 |
| on the origin of bacteriophage phix174 replicative form dna replication. | | 1976 | 779247 |
| "distinguishable steps in the enzymatic synthesis of bacteriophage phix174 replicative form in vitro". | | 1976 | 779776 |
| the process of infection with bacteriophage phix174. xxxix. the structure of a dna form with restricted binding of intercalating dyes observed during synthesis of phix single-stranded dna. | | 1976 | 781262 |
| the in vitro transcription units of bacteriophage phix174. i. characterization of synthetic parameters and measurement of transcript molecular weights. | | 1976 | 781282 |
| the in vitro transcription units of bacteriophage phix174. ii. in vitro initiation sites of phix174 transcription. | | 1976 | 781283 |
| process of infection with bacteriophage phi x174 xli. synthesis of defective phi x particles at 15 degrees c. | at 15 degrees c, phi x174-infected cells make single-stranded viral dna fragments, varying in size from 0.2 to 0.9 times that of phi x dna. in non-deproteinized lysates, this single-stranded dna is found associated with proteins in particles sedimenting heterogeneously with an s20, w average of 80 to 90s. these particles do not differ appreciably from mature virus in polypeptide composition. chase experiments, at 37 degrees c, of the label incorporated into this dna at 15 degrees c suggest that ... | 1976 | 785025 |
| host factor requirements and some properties of phixtb. an evolutionary aspect of phix-type phages. | replication of phixtb, a capsid mutant of bacteriophage phix174, depends on the host functions directed by the e.coli genes dnae, dnaf, dnag, dnaz, lig and rep. the cellular products of dnaa, dnab, dnac(d), dnai, dnap, pola, polb and xth genes are, however, dispensable for the viral growth. in these host factor requirements, phixtb resembles phages phik and st-1 rather than phix174. host ranges of phixtb, st-1 and phik overlap considerably, and growth temperature of the three phages is somewhat ... | 1976 | 790153 |
| the lipopolysaccharide receptor for bacteriophage phix174 and s13. | | 1975 | 1094681 |
| amino acid sequences from the gene f (capsid) protein of bacteriophage phix174. | | 1976 | 794486 |
| nucleotide sequence of the intercistronic region between genes g and f in bacteriophage phix174 dna. | | 1976 | 826639 |
| transcription and sequence analysis of a fragment of bacteriophage phix174 dna. | | 1976 | 826641 |
| biological effect of thymine ring saturation in coliphage phix174-dna. | | 1977 | 841010 |
| dna sequence at the c termini of the overlapping genes a and b in bacteriophage phi x174. | | 1977 | 859575 |
| nucleotide sequence of bacteriophage phi x174 dna. | a dna sequence for the genome of bacteriophage phi x174 of approximately 5,375 nucleotides has been determined using the rapid and simple 'plus and minus' method. the sequence identifies many of the features responsible for the production of the proteins of the nine known genes of the organism, including initiation and termination sites for the proteins and rnas. two pairs of genes are coded by the same region of dna using different reading frames. | 1977 | 870828 |
| assembly of bacteriophage phi x174: identification of a virion capsid precursor and proposal of a model for the functions of bacteriophage gene products during morphogenesis. | a capsomeric structure sedimenting with an s value of 108 in sucrose gradients was isolated from escherichia coli infected with bacteriophage phi x174. the 108s material contained viral proteins f, g, h, and d, and the relative amounts of these proteins in the 108s material were similar to those in the infectious 132s particle, which has previously been described as a possible intermediate in the assembly of 114s phage particles. electron micrographs indicated that the size and shape of the 108s ... | 1977 | 911401 |
| cross-contamination potential with dental equipment. | some types of reused dental equipment, especially handpieces and their attachments for drilling and cleaning teeth, might be responsible for cross-contamination if patient material were to lodge temporarily in difficult-to-disinfect internal mechanisms. this possibility is worrisome with respect to transmission of hepatitis b and human immunodeficiency viruses (hbv, hiv). previous cross-contamination studies have relied on laboratory experiments with bacteria or dye tracers. to assess possible r ... | 1992 | 1359320 |
| effect of operating variables on the separation of dna molecules by capillary polyacrylamide gel electrophoresis. | the influence of operating conditions on the separation of double stranded dna molecules in capillary polyacrylamide gel electrophoresis is presented in continuation of previous work. in this study, an equation was derived that relates the effects of electrophoresis variables such as gel concentration, field strength, molecular weight and temperature to the migration velocity. as a model system, phage phi x174 dna restriction fragments obtained by digestion with haeiii have been examined. as an ... | 1992 | 1362081 |
| isolation and characterization of the four major proteins in the virion of bacteriophage phix174. | a preparative method is described for the isolation of the major protein species from the virion of bacteriophage phix174. two proteins, the cistron g and h products, are located in the virion spikes. after removal of the spikes, the capsid contains the cistron f product as well as a small protein which is the product of cistron j and the majority of the dna. during the removal of the spikes, a precipitate containing the f and g proteins is formed. the proteins from the spike, capsid, or precipi ... | 1977 | 911773 |
| amino acid sequence of the small core protein from bacteriophage phix174. | the amino acid sequence of small core protein of bacteriophage phix174 has been determined by a combination of automated edman degradation of the intact polypeptide and by analysis of tryptic and thermolytic peptides. the six lysyl and six arginyl residues of this 37-residue polypeptide are concentrated in two structurally homologous 12-residue segments of the sequence. the hydrophobic residues of valine, tryptophan, tyrosine, and phenylalanine are contained in the carboxyl-terminal nine residue ... | 1977 | 911774 |
| viral dna-synthesizing intermediate complex isolated during assembly of bacteriophage phi x174. | a dna protein complex that is a precursor of mature phi x174 phage was isolated. the complex sedimented with an s value of 50 in a sucrose gradient and contained phage dna consisting of a replicative form molecule with an extended tail of single-stranded viral dna. the viral-strand dna ranged from one to two genomes in length. proteins coded on the phi x174 genome as well as the host genome were associated with the viral dna in the 50s precursor complex. our results indicated that both viral dna ... | 1976 | 957476 |
| overlapping genes in bacteriophage phix174. | | 1976 | 1004533 |
| transcription of bacteriophage phi-x174 in vitro: selective initiation with oligonucleotides. | | 1976 | 1018323 |
| transcription of bacteriophage phix174 in vitro: analysis with restriction enzymes. | | 1976 | 1018324 |
| the three-dimensional structure of frozen-hydrated bacteriophage phi x174. | the three-dimensional structure of bacteriophage phi x174 (phi x174) was determined to approximately 2.6 nm resolution from images of frozen-hydrated 114 s particles. the outer surface of phi x174 is characterized by several prominent features: (i) 12 mushroom-shaped caps (approximately 7.1 nm wide x 3.8 nm high) are situated at each of the vertices of the icosahedral virion and extend to a maximum radius of 16.8 nm; (ii) a "collar" of density surrounds the base of each apical cap; and (iii) 20 ... | 1992 | 1486007 |
| the effect of the termination rho factor and ribonuclease iii on the transcription of bacteriophage phi x174 dna in vitro. | | 1976 | 773703 |
| isolation and characterization of the protein coded by gene a of bacteriophage phix174 dna. | replication of phix174 circular replicative form (rfi) dna by extracts of escherichia coli infected with bacteriophage phix174 (amber in gene a) requires the phix174 gene a product. this requirement has been used as an assay for the isolation of this protein. the gene a product (purified 4000-fold) caused relaxation of superhelical phix174 rfi and formation of discontinuities in the viral strand of phix174 rfi uniquely situated in the a region of the genome, and yielded a complex after interacti ... | 1976 | 1066678 |
| mapping of in vivo messenger rnas for bacteriophage phix-174. | in vivo messenger rna for bacteriophage phix174 was fractionated in agarose gels into a number of discrete species ranging in size from 0.23 x 10(6) to 2.3 x 10(6) daltons. these rna species were eluted from the gels and hybridized to specific fragments derived from phix-174 replicative form dna by cleavage with restriction enzymes. a map of the orientation of in vivo messenger rnas with respect to the bacteriophage genetic map was constructed. this map indicated that initiation of messenger rna ... | 1976 | 1068463 |
| model system using coliphage phi x174 for testing virus removal by air filters. | short-term (15-min-duration) and long-term (5- to 6-day-duration) test procedures have been developed for determining the efficiency of the removal of bacteriophage phi x174 by air-sterilizing filters. these procedures were sensitive enough to measure a 10(8)-fold reduction in the number of bacteriophage. a filter commonly used in industrial air sterilizations (domnick-hunter bio-x borosilicate glass) effected a 10(8)-fold removal of viable phage in both short-term and long-term tests. a prototy ... | 1992 | 1575491 |
| the genetic map of bacteriophage phix174 constructed with restriction enzyme fragments. | | 1976 | 1084616 |
| cleavage map of bacteriophage phix174 rf dna by restriction enzymes. | phix rf dna was cleaved by restriction enzymes from haemophilus influenzae rf (hinf i) and haemophilus haemolyticus (hha. i). twenty one fragments of approximately 25 to 730 base pairs were produced by hinf i and seventeen fragments of approximately 40 to 1560 base pairs by hha i. the order of these fragments has been established by digestion on haemophilus awgyptius (hae iii) and arthrobacter luteus (alu i) endonuclease fragments of phix rf with hinf i and hha1. by this method of reciprocal dig ... | 1976 | 1085927 |
| formation of the parental replicative form of bacteriophage phix174. | | 1976 | 1086367 |
| gene f of bacteriophage phix174. correlation of nucleotide sequences from the dna and amino acid sequences from the gene product. | | 1976 | 1088826 |
| process of infection with bacteriophage phix174. xxxvii. rna metabolism in phix174-infected cells. | the rna produced in vivo from bacteriophage phix174 dna has been analyzed by polyacrylamide-agarose gel electrophoresis and sedimentation in dimethyl sulfoxide gradients, and the results of hayashi and hayashi (1970) have been confirmed and extended. an efficient procedure for recovery of rna from gels, followed by a hybridization assay, has indicated the presence in infected cells of 18 distinct rna species with sizes up to and greater than the unit (viral) length. the sizes of phix mrna's were ... | 1975 | 1089800 |
| growth of a capsid mutant of bacteriophage phi x174 in a temperature-sensitive strain of escherichia coli. | a capsid mutant of phix174 is capable of forming replicative form and synthesizing single strands at the restrictive temperature in a dnab mutant of escherichia coli. under similar conditions, the wild-type bacteriophage is incapable of either step in viral synthesis. | 1975 | 1089804 |
| 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 |
| bacteriophage phi x174 dna synthesis in escherichia coli hf4704s (dnahts) cells. | the dna synthesis of bacteriophage phix174 in escherichia coli hf470s, a mutant temperature sensitive in the initiation of dna replication (dnahts), has been examined. in hf4704s cells, phix174 can grow normally at 27 degree c whereas the phage cannot grow after the cessation of dna synthesis of the host cells at 42 degrees c. upon infection, phix174 dna can be injected into the host cell and the parental replicative form can be formed, but the progency replicative form cannot be synthesized at ... | 1975 | 1096950 |
| requirements for bypass of uv-induced lesions in single-stranded dna of bacteriophage phi x174 in salmonella typhimurium. | according to the current model for mutagenic bypass of uv-induced lesions, efficient bypass requires three proteins: activated reca (reca*) and either activated umud (umud') and umuc or their plasmid-encoded analogues, muca' and mucb. reca* aids synthesis of umud' and umuc (and muca'/mucb) at two levels: by inactivation of the lexa transcriptional repressor of these genes and by cleavage of umud (and muca) to produce the active fragments, umud' (muca'). a third role for reca is revealed when the ... | 1991 | 1847514 |
| synthesis of complex forms of bacteriophage phix174 double-stranded dna in a temperature-sensitive dnac mutant of escherichia coli c. | fast-sedimenting forms of bacteriophage phix174 double-stranded replicative-form dna observed in normal infections continued to accumulate at the nonpermissive temperature in a temperature-sensitive dnac mutant of escherichia coli. these complex molecules accounted for up to half of the dna synthesized during short pulses at the nonpermissive temperature. they were the dead-end products of dna synthesis, not intermediates in normal replicative-form replication. the data suggest that these higher ... | 1975 | 1097736 |