[effect of temperature on rna synthesis in escherichia coli crt 266 (dna bts) following infection with bacteriophage t3].infection of the temperature-sensitive e. coli crt 266 (dnabts) with t3-phages at the temperature of 30 degrees c and 35 degrees c, respectively, induced t3-specific rna synthesis with a maximum rate at 7 min (30 degrees c) and 4.5 min (35 degrees c) after infection. at temperatures above 40 degrees c no t3-induced rna synthesis could be observed. infection of e. coli cr 34--45 (dnab+) with t3 phages at 30 degrees c, 35 degrees c and at temperatures above 40 degrees c, however, produced t3-speci ...197994483
inactivation of escherichia coli by near-ultraviolet light and 8-methoxypsoralen: different responses of strains b/r and k-12.a series of escherichia coli k-12 ab1157 strains with normal and defective deoxyribonucleic acid repair capacity were more resistant to treatment with 8-methoxypsoralen (8-mop) and near-ultraviolet light (nuv) than a comparable series of strains from the b/r wp2 family although sensitivities to 254-nm ultraviolet light were closely similar. the difference was most marked with strains deficient in both excision and postreplication repair (uvra reca). the hypothesis that the internal level of 8-mo ...1979378972
[effect of temperature on formation of lysozyme in e. coli crt 266 (dnab ts) after infection with bacteriophage t3].lysozyme formation induced by bacteriophage t3 was studied in the ts-mutant e. coli crt 266 (dnabts) and in the wild-type e. coli cr 34--45 (dnab+) at different temperatures. it was found that lysozyme was formed in e. coli crt 266, however, no lysozyme synthesis took place at 41.5 degrees c. these results indicate that the expression of the lysozyme gene is disturbed in the ts-mutant at 41.5 degrees c.1978382720
dna sequences necessary for packaging bacteriophage t3 dna.a recombinant plasmid, puce1-tr, carrying a target for processing of the concatemer joint (tr) and sequences to the left of the target (e1), is efficiently packaged into transducing particles during t3 phage infection. using this plasmid packaging/transduction system, the minimal sequences necessary for packaging of t3 dna were determined. the tr sequence contains the targets for initiation cleavage and termination cleavage of concatemer processing (paccr and paccl, respectively). a plasmid lack ...19921546467
synthesis of the capsid protein inhibits development of bacteriophage t3 mutants that abortively infect f plasmid-containing cells.mutants of bacteriophage t3 that lack gene 1.2 resemble wild-type phage t7 in that they are unable productively to infect f plasmid-containing cells of escherichia coli. pseudorevertants of a t3 gene 1.2 deletion mutant that have regained the ability to plate efficiently on male cells have been isolated and characterized. at least two mutations in the gene for the major capsid protein are necessary for these phages to bypass f-mediated restriction. one mutation serves to reduce the rate of synth ...19892668535
initiation, release, and reinitiation of rna chains by bacteriophage-t3-induced polymerase from t3 dna templates (e. coli-guanosine triphosphate terminus-purified polymerase).bacteriophage t3-induced rna polymerase, upon copying its specific template, native t3 dna, initiates rna chains only with gtp. denaturation of the dna results in loss of template specificity for the polymerase. with denatured t3 dna as template, t3 polymerase initiates rna chains with both atp and gtp, and the average length of the resulting rna chains is markedly reduced. studies of the polymerase reaction with native t3 dna in vitro show that t3 polymerase is able to terminate rna synthesis w ...19724550510
regulation of host ribonucleic acid synthesis in bacteriophage t3-infected cells. properties of an inhibitory protein of escherichia coli ribonucleic acid polymerase. 19744594239
isolation of dna segments containing promoters from bacteriophage t3 dna. 19744611486
induction of a new rna polymerase in escherichia coli infected with bacteriophage t3. 19714930861
native and denatured dna of phage t3 and of e. coli b as templates for rna polymerase. 19694975275
role of differential air pressure zones in the control of aerosols in a large animal isolation facility.the uncontrolled transmission of hog cholera in a large animal isolation facility, designed to control the movement of aerosols within and between individual wings of a multiunit building, indicated the need for a critical study of aerosol behavior under existing conditions of operation. studies with aerosols of escherichia coli b t3 bacteriophage (t3 coliphage) conclusively demonstrated the impossibility of obtaining the desired control by means of a "static" air balance relationship between ad ...19665951332
bacteriophage t3 and bacteriophage t7 virus-host cell interactions. 19816261110
transcription termination by bacteriophage t3 and sp6 rna polymerases at rho-independent terminators.transcription termination of t3 and sp6 dna-dependent rna polymerases have been studied on the dna templates containing the threonine (thr) attenuator and its variants. the thr attenuator is from the regulatory region of the thr operon of escherichia coli. the dna template, encoding the thr attenuator, contains specific features of the rho-independent terminators. it comprises a dg + dc rich dyad symmetry, encoding a stem-and-loop rna, which is followed by a poly(u) region at the 3'-end. thirtee ...19979476351
lowering s-adenosylmethionine levels in escherichia coli modulates c-to-t transition mutations.deoxycytosine methylase (dcm) enzyme activity causes mutagenesis in vitro either directly by enzyme-induced deamination of cytosine to uracil in the absence of the methyl donor, s-adenosylmethionine (sam), or indirectly through spontaneous deamination of [5-methyl]cytosine to thymine. using a lac reversion assay, we investigated the contribution of the first mechanism to dcm mutagenesis in vivo by lowering the levels of sam. escherichia coli sam levels were lowered by reducing sam synthetase act ...200111208790
preliminary crystallographic analysis of the bacteriophage p22 portal protein.portal proteins are components of large oligomeric dsdna pumps connecting the icosahedral capsid of tailed bacteriophages to the tail. prior to the tail attachment, dsdna is actively pumped through a central cavity formed by the subunits. we have studied the portal protein of bacteriophage p22, which is the largest connector characterized among the tailed bacteriophages. the molecular weight of the monomer is 82.7 kda, and it spontaneously assembles into an oligomeric structure of approximately ...200212372319
effects of mitomycin and alpha-rays on the capacity of escherichia coli b for phage t3. 196313953928
metagenomic detection of phage-encoded platelet-binding factors in the human oral cavity.the human oropharynx is a reservoir for many potential pathogens, including streptococcal species that cause endocarditis. although oropharyngeal microbes have been well described, viral communities are essentially uncharacterized. we conducted a metagenomic study to determine the composition of oropharyngeal dna viral communities (both phage and eukaryotic viruses) in healthy individuals and to evaluate oropharyngeal swabs as a rapid method for viral detection. viral dna was extracted from 19 p ...201120547834
a novel method for generating nested deletions using the in vitro bacteriophage t3 dna packaging sequence a dna segment inserted into a cosmid vector under the directed sequencing strategy, we established a simple and rapid method for generating nested deletions which uses the in vitro packaging system of bacteriophage t3 dna. the principle is based on the previous finding that this system can translocate any linear double-stranded dna up to 40 kb into the phage capsid in a time-dependent manner and the encapsulated dna becomes dnase-resistant. for this purpose, we constructed a cosmid v ...19947719924
tau factor from escherichia coli mediates accurate and efficient termination of transcription at the bacteriophage t3 early termination site in vitro.the termination signal that limits transcription through the early region of bacteriophage t3 (t3te) has been cloned and sequenced. the nucleotide sequence of t3te is identical with that of t7te, with the exception of a single g to u substitution in the 3' tail of the terminated transcript, and addition of an ac to the loop in the terminator stem-loop, enlarging the loop to six residues. previous studies of the properties of t3te have shown that this site is rho independent and is highly efficie ...19873323530
abortive initiation by bacteriophage t3 and t7 rna polymerases under conditions of limiting substrate.initiation of rna synthesis by the phage polymerases is abortive if the concentration of pyrimidine triphosphates is limiting. under abortive initiation conditions the polymerases repeatedly initiate transcription but produce ribooligonucleotides that terminate just prior to the first occurrence of the limiting substrate. abortive initiation is most severe if the limiting substrate occurs within the first 8-12 nucleotides of the nascent rna chain and is particularly evident when ump is limiting. ...19892646596
three-dimensional structure of t3 connector purified from overexpressing bacteria.the bacteriophage t3 connector has been purified from overexpressed protein in escherichia coli, harboring a plasmid containing the gene encoding p8 protein. the connector, which is composed of 12 copies of p8, has been crystallized in two-dimensional sheets and studied by electron microscopy from negatively stained specimens. a two-dimensional fourier filtering and averaging procedure was performed with crystalline specimens. in addition, single particle averaging techniques were used with othe ...19921548694
cross-resistance of escherichia coli b/r to cis-platinum (ii) diamminochloride, uv light and alkylating agents.gradual transfers of the strain escherichia coli b/r on m9 agar with increasing concentrations of cis-platinum (ii) diamminochloride (cis-pt(ii)) yielded a resistant strain sm 405 capable of growing on liquid m9 medium containing 250 mum cis-pt(ii). the parent strain escherichia coli b/r is completely inhibited in both division and growth at cis-pt(ii) concentrations as low as 30 mum. the resistant mutant has a longer doubling time than the parent strain. no other differences were found between ...1975170174
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