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competitive inhibition of transformation in group h streptococcus strain challis by heterologous deoxyribonucleic acid.glucosylated deoxyribonucleic acid (dna) from phages t4 and t6 competes poorly with homologous dna causing only a slight decrease of transformation in group h streptococcus strain challis. other types of heterologous dnas (micrococcus luteus, clostridium perfringens, escherichia coli, calf thymus and non-glucosylated phage t6 dna), in contrast to glucosylated t4 and t6 dnas, compete with transforming dna to the normal, high extent. these results indicate that as in transformation of bacillus sub ...1975172490
cyclic adenosine 3',5'-monophosphate regulation of the bacteriophage t6/colicin k receptor in escherichia coli.mutant strains of escherichia coli unable to synthesize cyclic adenosine 3',5'-monophosphate (camp) or the cyclic adenosine monophosphate receptor protein (crp) were more resistant than wild-type cells to infection by bacteriophage t6. this resistance was found to be associated with the decreased production of specific t6 receptor protein (also the colicin k receptor) located in the outer membrane protein fraction of these cells. transcription of this particular outer membrane protein was regula ...1979227838
receptors for t2, t4 and t6 phages in sh. dysenteriae 7 and other serotypes of sh. dysenteriae.the sensitivity of four strains of sh. dysenteriae and of nine strains representing other serotypes of sh. dynsenteriae to phages t2, t4 and t6 was examined. different extracts, prepared from sensitive strains were tested for their capacity of phage inactivation. we found that the receptor substance for phage t2 is localized differently in various strains: in sh. dysenteriae 7, it was found in bacterial extracts obtained by water/phenol at 68 degrees c and in extracts obtained by trichloracetic ...1975766504
outer membrane of escherichia coli k-12: tsx mutants (resistant to bacteriophage t6 and colicin k) lack an outer membrane protein. 1976786287
phage t6--colicin k receptor and nucleoside transport in escherichia coli. 1976791677
fate of heterologous deoxyribonucleic acid in bacillus subtilis.cscl density gradient fractionation of cell lysates was employed to follow the fate of escherichia coli, phage t6, and non-glucosylated phage t6 deoxyribonucleic acid (dna) after uptake by competent cells of bacillus subtilis 168 thy minus trp minus. shortly after uptake, most of the radioactive escherichia coli or non-glucosylated t6 dna was found in the denatured form; the remainder of the label was associated with recipient dna. incubation of the cells after dna uptake led to the disappearan ...1975805125
analysis of a mutated phage t6 receptor protein of escherichia coli k 12.the tsx-206 allele encodes an altered tsx protein, tsx-206, that can no longer function as the t6 receptor. we show here that this allele also confers resistance to the tsx-specific phages h1, h3, h8, k9, k18 and ox1 but not to colicin k. the tsx-206 protein still mediates the efficient permeation of deoxyadenosine across the outer membrane at low substrate concentration. a host-range mutant of phage t6, t6h3.1, was isolated which can use both the tsx-206 and the tsx wild-type protein as its rec ...19902199819
analysis of the tsx gene, which encodes a nucleoside-specific channel-forming protein (tsx) in the outer membrane of escherichia coli.the tsx gene of escherichia coli encodes an outer membrane protein, tsx, which constitutes the receptor for colicin k and bacteriophage t6, and functions as a substrate-specific channel for nucleosides and deoxynucleosides. the mini-mu element peg5005 was used to prepare a gene bank in vivo, and this bank was used to identify t6-sensitive strains carrying the cloned tsx gene. subcloning of the tsx gene into the multicopy plasmid, pbr322, resulted in a strong overproduction of tsx. the sequence o ...19902265760
bacteriophage t4 early promoter regions. consensus sequences of promoters and ribosome-binding sites.twenty-nine early promoters from bacteriophage t4 and 14 early promoters from bacteriophage t6 were isolated using vector m13hdl17, a promoterless derivative of m13mp8 carrying a linker sequence, the bacteriophage lambda-terminator tr1, and the lacz' gene including part of its ribosome-binding site. the consensus sequence for the t4 promoters is: (sequence; see text). ribosome-binding sites of t4 share the sequence: 5'...g.ggaga..aa.atgaa.a...3' the consensus sequence of the t4 early promoter re ...19892810355
relationship between bacteriophage t4 and t6 dna topoisomerases. t6 39-protein subunit is equivalent to the combined t4 39- and 60-protein subunits.t6 dna topoisomerase has been purified from bacteriophage t6 infected escherichia coli. unlike the t4 dna topoisomerase which has three subunits, it consists of two subunits of molecular weights 75,000 and 51,000. they are the products of t6 genes 39 and 52, respectively. the purified t6 enzyme can stimulate in vitro t6 dna replication. it has an atp-dependent dna relaxation activity similar to the t4 enzyme. either atp or datp can be used in both reactions. using a "western blotting" and radioi ...19852991231
t-even bacteriophage-tolerant mutants of escherichia coli b. ii. nucleic acid metabolism.t-even bacteriophage-tolerant mutants are strains of escherichia coli which can adsorb t-even phages but cannot support the growth of infective virus. under some conditions, the infected cells are not killed. mutant cells infected by phage t6 are able to carry out several metabolic functions associated with normal virus development, including arrest of bacterial nucleic acid and protein synthesis, incorporation of isotopic precursors into viral nucleic acids and proteins, synthesis of early enzy ...19714940928
[dynamics of adsorption of anti-brucella phage t6 on the cells of br. abortus, melitensis and suis]. 19684976645
use of uv-irradiated bacteriophage t6 to kill extracellular bacteria in tissue culture infectivity assays.we have utilized 'lysis from without' mediated by uv-inactivated bacteriophage t6 to eliminate extracellular bacteria in experiments measuring the internalization, intracellular survival and replication of yersinia pestis within mouse peritoneal macrophages and of shigella flexneri within a human intestinal epithelial cell line. the technique we describe has the following characteristics: (a) bacterial killing is complete within 15 min at 37 degrees c, with a greater than 10(3)-fold reduction in ...19836338113
lipopolysaccharide requirement of phage t6 inactivation in escherichia coli k12.t6-phage inactivation by homogeneous, lipopolysaccharide-free tsx protein showed a clear dependence on added lipopolysaccharide, when assayed in the presence of a non-ionic detergent, octyl-polyoxyethylene (octyl-poe). under these conditions, the protein exists in a monomeric state.19827044210
determination of enteroviruses, hepatitis a virus, bacteriophages and escherichia coli in adriatic sea mussels.the aim of the present study was to evaluate the incidence of enteric viruses in mussels and to verify the possibility of using phages as indirect indicators of mussel viral contamination. mussels (36 samples) collected from three different areas of the adriatic sea were analysed to determine the following parameters: escherichia coli, somatic coliphage (t6 phage), f-plus (ms2 phage), b40-8 (phage of bacteroides fragilis), enteroviruses and hepatitis a virus. most of the results of the bacteriol ...200010735998
an x-ray study of a colicine and of its relationship to bacteriophage t6. 195513267979
reproduction of bacteriophage t6 and t7 in auxotrophic mutants of e. coli b. 195513327857
vitamin content of purified typhus rickettsiae, tobacco mosaic virus, and coliphage t6. 195613382844
direct and indirect inactivation of bacteriophage t6 containing halogenated dna. 196414114192
inactivation of bacteriophage t6 in an aqueous system by high energy protons. 196514309651
physicochemical properties of bacteriophages. ii. sedimentation of bacteriophage t6. 195114841151
physicochemical properties of bacteriophages. iii. diffusion of bacteriophage t6. 195114841152
purification and properties of e. coli bacteriophage t6. 194818858195
biochemical studies of virus reproduction; chemical composition of escherichia coli bacteriophage t6 and its host. 194915390408
glucosylated nucleotide sequences from t-even bacteriophage deoxyribonucleic acids.1. the frequencies of various pyrimidine nucleotide sequences in phage-t2vg111 dna and phage-t6 dna have been measured. the hydroxymethylcytosine nucleotides that bear glucosyl groups in phage-t2vg111 dna and gentiobiosyl groups in phage-t6 dna are not randomly distributed. 2. sequences in which two or three hydroxymethylcytosine nucleotides are terminated at both ends by purine nucleotides bear only one sugar substituent and this is attached to the first hydroxymethylcytosine when the sequences ...196514342507
the mutation of e. coli to resistance to bacteriophage t6. 195313114913
aspects of the ultraviolet photobiology of some t-even bacteriophages.bacteriophage t4 dna metabolism is largely insulated from that of its host, although some host functions assist in the repair of t4 dna damage. environmental factors sometimes affect survival and mutagenesis after ultraviolet (uv) irradiation of t4, and can affect mutagenesis in many organisms. we therefore tested the effect of certain environmental factors and host genetic defects upon spontaneous and uv-induced mutagenesis and survival in t4 and some related t-even phages. plating at ph 9 enha ...19989560380
the reaction of bacteriophage t6 with tryptophan. an improved description of t-even tail-fibre extension. 19827120388
exchange of colicin receptor capacity between strains of escherichia coli sensitive or resistant to colicin k-k235.phage and colicin-resistant mutants were derived from escherichia coli k-12p678. two classes of phage t6 and colicin k-resistant mutants (genotype tsx) were isolated. tsx-2 mutants, which demonstrated mucoid growth and increased sensitivities to many antibiotics, became sensitive to colicin k when pretreated with ethylenediaminetetraacetate (edta), whereas tsx-1 mutants did not. reassociation of edta-released material partially restored resistance to colicin k for tsx-2 mutants. when edta-releas ...19826808961
recombinant f' factors from escherichia coli k-12 strains carrying recb or recc.the frequency of genetic exchanges between f' factors and the bacterial chromosome was studied in recombination-deficient escherichia coli mutants under conditions in which the recombinant f' factors were immediately transferred to new hosts. in a series of double matings, f101-1 thr(+)leu(-) episomes were first transferred into each of four intermediate f(-)thr(-)leu(+) strains carrying various rec alleles. after the original f' donors were killed with phage t6, the f101-1 episomes were then tr ...19724553837
mutagenesis by normal metabolites in escherichia coli: phenylalanine mutagenesis is dependent on error-prone dna repair.in search of a model for the production of 'spontaneous' mutations induced by dna damage produced during normal metabolism, 19 amino acids were tested for mutagenicity in escherichia coli k-12 uvrb. cystine, and, to a lesser extent, arginine and threonine were found to be antimutagenic; only phenylalanine was found to be mutagenic. at 2 mm, phenylalanine induced mutants at 1.5-2-fold above background [lacz53(amber)----lac+, rifampicin resistance (missense), and bacteriophage t6 resistance]. tyro ...19863523223
stable albicidin resistance in escherichia coli involves an altered outer-membrane nucleoside uptake system.albicidin blocked dna synthesis in intact cells of a pola- enda- escherichia coli strain, and in permeabilized cells supplied with all necessary precursor nucleotides, indicating a direct effect on prokaryote dna replication. replication of phages t4 and t7 was also blocked by albicidin in albicidin-sensitive (albs) but not in albicidin-resistant (albr) e. coli host-cells. all stable spontaneous albr mutants of e. coli simultaneously became resistant to phage t6. the locus determining albicidin ...19902191080
letter: the sensitivity of e. coli phage t6 to inactivation by selective inorganic radicals. 19751080143
heterologous deoxyribonucleic acid uptake and complexing with cellular constituents in competent bacillus subtilis.with competent cultures of bacillus subtilis the uptake of escherichia coli deoxyribonucleic acid (dna) is about 50% that for homologous dna. uptake of phage t6 dna, if any, is of the order of 7%, while nonglucosylated phage t6 (t6) dna is taken up almost as effectively as homologous dna. both t6 and t4 dna interfere only minimally with uptake of homologous dna; by contrast, t6 dna competes with homologous dna as effectively as the latter itself. these results indicate that the glucose residues ...1975811646
growth of the escherichia coli cell surface.phage t6 was used as a label to follow the growth of the outer membrane in a strain of escherichia coli temperature sensitive for the production of the t6 receptor. extension of the surface takes place at the cell poles. small cells extend at only one pole, whereas larger cells grow from both poles. the change from unipolar to bipolar growth appears to depend on the attainment of a particular cell size and not on completion of chromosome replication.1977321431
genome plasticity in the distal tail fiber locus of the t-even bacteriophage: recombination between conserved motifs swaps adhesin specificity.the adsorption specificity of the t-even phages is determined by the protein sequence near the tip of the long tail fibers. these adhesin sequences are highly variable in both their sequence and specificity for bacterial receptors. the tail fiber adhesin domains are located in different genes in closely related phages of the t-even type. in phage t4, the adhesin sequence is encoded by the c-terminal domain of the large tail fiber gene (gene 37), but in t2, the adhesin is a separate gene product ...19989737921
identification of a segment of the escherichia coli tsx protein that functions as a bacteriophage receptor area.the escherichia coli outer membrane protein tsx functions as a nucleoside-specific channel and serves as the receptor for colicin k and a number of t-even-type bacteriophages, including phage t6. to identify those segments of the tsx protein that are important for its phage receptor function, we devised a selection and screening procedure which allowed us to isolate phage-resistant strains synthesizing normal amounts of tsx. three different tsx-specific phages (t6, ox1, and h3) were employed for ...19938491700
biochemical studies of virus reproduction; purification and properties of escherichia coli bacteriophage t6. 194918119244
gentiobiose, a constituent of deoxyribonucleic acid from coliphage t6. 196214460593
pore-forming activity of the tsx protein from the outer membrane of escherichia coli. demonstration of a nucleoside-specific binding site.the tsx protein from the outer membrane of escherichia coli is known to be involved in the permeation of nucleosides across the outer membrane under limiting substrate conditions. we purified tsx from an e. coli strain that overproduces tsx. the purified protein was still functional since it could neutralize the tsx-specific bacteriophage t6 in vitro. when the purified tsx was reconstituted into a lipid bilayer, there was a large increase of the membrane conductance, indicating pore-forming acti ...19883276691
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