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At least 19 recordsLinked to original sources

PubMed1976

Packaging of genomes in bacteriophages: a comparison of ssRNA bacteriophages and dsDNA bacteriophages.

In complex DNA bacteriophages like lambda, T4, T7, P22, P2, the DNA is packaged into a preformed precursor particle which sometimes has a smaller size and often a shape different from that of the phage head. This packaging mechanism is different from the one suggested for the RNA phages, according to which RNA nucleates the shell formation. The different mechanisms could be understood by comparing the genomes to be packaged: single stranded fII RNA has a very compact structure with high helix content. It might easily form quasispherical structures in solution (as seen in the electron microscope by Thach & Thach (1973)) around which the capsid could assemble. Double stranded phage DNA, on the other hand, is a rigid molecule which occupies a large volume in solution and has to be concentrated 15-fold during packaging into the preformed capsid, and the change in the capsid structure observed hereby might provide the necessary DNA condensation energy.

Bacteriophages↗

PubMed1978

Incidence of Vibrio parahaemolyticus bacteriophages and other Vibrio bacteriophages in marine samples.

Vibrio bacteriophages were isolated by enrichment from 177 of 643 samples of marine molluscan shellfish, crustaceans, seawater, and sediments. The predominant bacteriophage types isolated were specific for some strains of Vibrio parahaemolyticus. A high frequency of phage isolations was also observed with strains of agar-digesting vibrios (21 of 56) and psychrophilic vibrios (14 of 72) that were originally isolated from non-shellfish growing areas. No bacteriophages were isolated against V. alginolyticus and only rarely for V. anguillarum even though these were the two most abundant species found in near-shore environments. No V. cholerae phages were isolated. It was also determined from quantitative studies on the Pacific oyster (Crassostrea gigas) obtained from two environments in Washington and Oregon that the titers of V. parahaemolyticus bacteriophages increased with increasing seasonal water temperatures and that this was proportional to the increase in numbers of mesophilic vibrios and not with the incidence of V. parahaemolyticus. Titers of V. parahaemolyticus bacteriophages occasionally exceeded 10(6) per g of oyster during the summer months. Specific V. parahaemolyticus bacteriophages were also isolated from market seafoods and other marine samples that originated in cold environments where no mesophilic vibrios are expected to be found. The possibility that V. parahaemolyticus bacteriophages originate from Vibrio spp. other than V. parahaemolyticus and the role of these bacteriophages in the ecology of marine vibrios are discussed.

Animals↗

PubMed1975

Thymineless bacteriophage induction in Staphylococcus aureus. I. High-frequency transduction with lysates containing a bacteriophage related to bacteriophage phi 11.

A thymine-requiring mutant of Staphylococcus aureus, strain 8325 (PI258)thy, undergoes prophage induction and lysis after thymine starvation. Four different phages were isolated from the lysate in low titers, among which was a phage designated phi 14, which differs from phage phi 11 in its immunity locus. The thymineless induced lysates of strain 8325(PI258)thy transduce the penicillinase plasmid at high frequency (10(-1), whereas transduction of chromosomal markers is inefficient. A plasmic-cured derivative of strain 8325(PI258)thy is also lysed by thymine starvation and be used for high-frequency transduction of other plasmids. Reconstitution of a strain of S. aureus that responds to thymine starvation was only partially successful, but this system can effectively be used to transduce plasmids or plasmid derivatives.

Drug Resistance, Microbial↗

PubMed1977

Temperate Bacillus subtilis bacteriophage phi 3T: chromosomal attachment site and comparison with temperate bacteriophages phi 105 and SPO2.

The temperate Bacillus subtilis bacteriophage phi 3T contains within its genome a locus, designated thyP3, that encodes for a protein with thymidylate synthetase activity. Bacteriophage phi 3T is different from the two previously characterized temperate phages, phi 105 and SPO2, in: heteroimmunity, response to bacteriophage antisera, endonuclease digestion pattern, induction in the presence of 6-(p-hydroxyphenylazo)-uracil, and effect on the lytic cycle of bacteriophage phi 1. The mean burst size of phi 3T is 56. The dose response curve with bacteriophage phi 3T DNA is linear for transfection and transformation to the Thy+ phenotype. The inserted prophage has been mapped by PBS1 transduction; it is between chromosomal markers ilvA8 and gltA in the terminus of the chromosome. Thus thyP3 maps at a site separate from, but between, the bacterial markers thyA and thyB when thyP3 is in the prophage state.

Bacillus subtilis↗

PubMed1975

Molecular mechanisms in alkylation mutagenesis. Induced reversion of bacteriophage T4rII AP72 by ethyl methanesulphonate in relation to extent and mode of ethylation of purines in bacteriophage deoxyribonucleic acid.

Survival and reversion to T4r+ of bacteriophage T4rII AP72 after treatment with ethyl methanesulphonate at 37 degrees or 45 degrees C were studied in relation to the extent and mode of alkylation of purines in DNA of ethylated bacteriophage. A single-burst technique was used for reversion assay. Survival was lower at 45 degrees C than at 37 degrees C at a given extent of ethylation of bacteriophage DNA, confirming that events subsequent to ethylation, probably depurinations, are the main cause of decreased survival. Reversion was positively correlated (approximately linearly except at low extents at 37 degrees C) with ethylation of bacteriophage DNA, showing that ethylation itself causes mutation. Following the concept that reversion results from G-C leads to A-T transition at a single site (Krieg, 1963a,b) and the suggestion that O6-alkylation of guanine generates the miscoding base (Loveless, 1969), it was calculated that about one-third of induced O6-ethylguanines at this site would miscode to induce mutation.

Alkylation↗

PubMed1977

Structural aberrations in T-even bacteriophage. IX. Effect of mixed infection on the production of giant bacteriophage.

To date, the production of T-even bacteriophage with giant heads has been achieved in two ways: (i) by use of canavanine-arginine treatment of Escherichia coli B cultures infected by wild-type bacteriophage (Cummings and Bolin, Bacteriol. Rev. 40:314-359, 1976; Cummings et al., Virology 54:245-261, 1973), which give a size distribution of giants that is phage specific (Cummings et al., Virology 54:245-261, 1973); and (ii) by infection with certain missense mutants of T4D gene 23 (Doermann et al., J. Virol. 12:374-385, 1973; ICN-UCLA Symposium on Molecular Biology, p. 243-285, 1973) or temperature-sensitive mutants of gene 24 (Aebi et al., J. Supramol. Struct. 2:253-275, 1974; Biljenga et al., J. Mol. Biol. 103:469-498, 1976). We now report the effect of mixed infection with several mutants of T4D on both the production and the size of giant bacteriophage. We found that gene 24 mutant is a critical partner for the production of giants. Infection using T4.24 mutants together with either T4.23 mutants, T4B+ or T6+ led to the formation of giants with heads 10- to 14-fold longer than normal-length heads. Infection with amber 24-bypass 24 double mutants of T4D led to the production of giants when gene 23 mutant was used to co-infect. Addition of canavanine to the co-infected cultures could alter the size distribution of giants, depending on which phage were used to coinfect. Gene 22 mutants had a modifying effect on these results. In the absence of canavanine co-infection with gene 22 mutants prevented the production of giants, and in the presence of canavanine giants of 1.5 to 5 head lengths were found. We have interpreted these results to mean that critical concentrations of gene products 22, 23, and 24 interact to control head length in T-even bacteriophage.

Arginine↗

PubMed1977

Effect of site-specific endonuclease digestion on the thyP3 gene of bacteriophage phi 3T and the thyP11 gene of bacteriophage rho11.

phi 3T and rho11 are closely related bacteriophages of Bacillus subtilis which can "convent" thymine auxotrophs to thymine prototrophs upon infection or transfection. The effect of endonuclease digestion on the ability of both bacteriophage and prophage DNA from phi eT and rho11 to transform for thymine prototrophy was determined. All of the endonucleases tested: BamHI, Bg/II, BsuRI, EcoRI, HindII+ III, and HpaII reduced the efficiency of thyP transformation to an equal extent in prophage and bacteriophage DNA. Only HpaII completely abolished thyP transformation. The reduction in transformation with BamHI, Bg/II, BsuRI, EcoRI, and HpaII fragments is size related. The thyP transforming fragments generated by these endonucleases are potentially clonable.

Bacillus subtilis↗

PubMed1976

In vitro construction of bacteriophage lambda and plasmid DNA molecules containing DNA fragments from bacteriophage T4.

Restriction endonucleases EcoRI and HindIII generated fragments of T4 cytosine-containing DNA were inserted into bacteriophage vector lambdagtSuIII and plasmid vectors pMB9 and pBR313. Resulting clones were screened for hybridization with 32P labeled T4 tRNA. Recombinant bacteriophages and plasmids were isolated which contained a T4 fragment coding for T4 RNA species 1 and 2 and T4 tRNA Arg. Selected lambda-T4 hybrid bacteriophages were grown to high titer and their DNA analyzed by gel electrophoresis.

Coliphages↗

PubMed1977

Structure and synthesis of a lipid-containing bacteriophage. An endolysin activity associated with bacteriophage PM2.

Endolysin was induced in Pseudomonas BAL-31 infected with bacteriophage PM2 and was also associated with the purified virion. This enzyme required divalent cations for its activity, Ca2+ being the most effective cation. Endolysin activity in the virion increased up to three-fold upon disruption and the activity could be localized in the viral nucleocapsid. Thus the enzyme is localized within the virion. After purification of the structural proteins of bacteriophage PM2, only the nucleocapsid protein (III) had endolysin activity.

Bacteriolysis↗

PubMed1978

Structure and synthesis of a lipid-containing bacteriophage. Total reconstitution of bacteriophage PM2 in vitro.

The lipid-containing bacteriophage PM2 was reconstituted stepwise from its purified denatured subunits. In the first step the nucleocapsid was reconstituted from the DNA and the two nucleocapsid proteins. Slight biochemical differences between reconstituted nucleocapsids and those isolated from native virus were seen. Combination of reconstituted nucleocapsid or nucleocapsid from virions with the coat and spike proteins in the presence of the viral lipids resulted in the formation of infectious virus in both cases. The reconstituted particles contained amounts of viral components similar to those in native virus, except for the lipid content. The amount of lipids present in the reconstituted particles was twice as high as the lipid content of native bacteriophage.

Bacteriophages↗

PubMed1976

Streptococcal bacteriophage 12/12-borne hyaluronidase and its characterization as a lyase (EC 4.2.99.1) by means of streptococcal hyaluronic acid and purified bacteriophage suspensions.

Hyaluronic acid was obtained from filtrates of heat-killed cultures of Streptococcus pyogenes group A, strain K56, by simple ethanol precipitation and treatment with an adsorbent. The hyaluronic acid is pure as judged from chemical and sedimentation analyses. Particles of streptococcal bacteriophage 12/12 were isolated from phage-lysed group A streptococci by polyethylene glycol precipitation and isopyenic centrifugation. Electron micrographs of negatively stained preparations showed a typical Bradley group B virus with a long, flexible, cross-striated tail and a knob- or star-like structure at the distal tip of the tail. The hyaluronic acid is depolymerized upon incubation with the phage 12/12 virions. After extensive digestion, a mixture of at least four oligosaccharides is formed, the two smallest of which are a tetra- and octasaccharide terminating in reducing N-acetyl-D-glucosamine. The tetrasaccharide shows an absorption maximum at 231.5 nm with a molar extinction coefficient epsilon = 4820 litres X mole-1 X cm-1, and it is therefore concluded that the bacteriophage-borne hyaluronidase catalyses a beta-elimination. Accordingly it is classified as a hyaluronate lyase (EC 4.2.99.1).

Bacteriophages↗

PubMed1976

Bacteriophage N3 of Haemophilus influenzae. II. Infection of transformable cells by bacteriophage DNA.

Transfection of H. influenzae with N3 bacteriophage DNA shows a dependence on concentration of DNA and a sigmoidal shape of uptake of DNA. The efficiency of transfection is decreased in the two types of recombination-defective strains of H. influenzae; rec1- and rec2-. The fact that N3 bacteriophage can code for its own recombination system but transfection is dependent on host recombation system allows the conclusion that the primary recombination during transfection with N3 phage DNA is mediated exclusively by the bacterial recombination system.

Bacteriophages↗

PubMed1979

Cloning of bacteriophage T5 DNA fragments in plasmid pBR322 and bacteriophage lambda gtWES.

Bacteriophage T5 was digested with the restriction endonucleases HindIII and EcoRI and the resulting fragments were inserted into the plasmid pBR322 and the bacteriophage lambda gtWES as vectors. Approx. 15% of the phage genome was recovered in recombinant clones. The recombinants were characterized by restriction analysis, DNA/DNA hybridization employing Southern blots, and ability to complement or recombine with amber mutants of T5. The results obtained allow revisions of the physical map of the T5 genome and partial correlation of the physical map with the genetic map.

Chromosome Mapping↗

PubMed1978

Insertion of bacteriophage lambda into the deo operon of Escherichia coli K-12 and isolation of plaque-forming lambdadeo+ transducing bacteriophages.

A procedure has been devised to isolate plaque-forming lambda cI857S7 transducing bacteriophage which carry the internal promoter, P3, of the deo operon of Escherichia coli and the deoB and deoD genes, while lacking the deoP and cytP promoters of the same operon, in order to study, specifically, regulation at the P3 site. This has been accomplished by selecting for the insertion of bacteriophage lambda into the deoA gene in a strain deleted for the normal lambda attachment site (delta att lambda) and isolating from this lysogen lambda spi- and lambda EDTAr phage. Among these, lambda pdeoB+D+ phage were identified by their transducing abilities. From in vivo enzyme induction experiments performed on a delta deo strain lysogenized with such phage, they were shown to carry the P3 promoter while lacking the deoP and cytP promoters. A lambdapdeo B+D+ phage phage was used to lysogenize a deo+ delta att lambda strain, integration of lambda occurring within the region of homology, and, from a heat-induced lysate of this strain, a plaque-forming lambda+ phage carrying the complete deo operon was obtained. Phage lambda was also inserted into the deoB and deoD genes and into the tdk gene. By isolating lambdaspi- and lambdaEDTAr phage from the deo::(lambda) mutants and determining which bacterial genes they carried and whether they retained the int gene of lambda, it was found that lambda had inserted into deoD with the same orientation as lambda inserted into attlambda, whereas lambda inserted into deoA and deoB had the opposite orientation. Deletions extending from the site of lambda insertion into the bacterial chromosome were isolated by selecting for heat-resistant revertants. These confirmed the order of markers to be deo-serB-trpR-thr and also placed a locus, msp, determining sensitivity or resistance of male strains to male-specific phages, between trpR and thr. For some reason unknown, but which may be related to the orientation of the lambda prophages, short deletions rendering the bacterium Ser- Thr+ were of much lower frequency from the deoD::(lambda) lysogen than from the other two lysogens. From an examination of the residual deoD enzyme levels in deoB::(lambda) mutants, it was deduced that there may be two promoter sites within the deoB::(lambda) mutants, it was deduced that there may be two promoter sites within the deoB gene, transcription from one of these being sufficient to account for the noncoordinate nature of the induction of deoB and deoD gene products.

Chromosome Mapping↗

PubMed1979

Transduction of bacteriophage lambda by bacteriophage T1.

When bacteriophage T1 was grown on bacteriophage lambda-lysogenic cells, phenotypically mixed particles were formed which had the serum sensitivity, host range, and density of T1 but which gave rise to lambda phage. T1 packaged lambda genomes more efficiently both when the length of the prophage was less than that of wild-type lambda and when the host cell was polylysogenic. Expression of the red genes of lambda or the recE system of Escherichia coli during T1 growth enhanced pickup of lambda by T1, whereas packaging was reduced in recB cells. If donors were singly lysogenic, the expression of transduced lambda genomes as a PFU required lambda-specified excisive recombination, whereas lambda genomes transduced from polylysogens required only lambda- or E. coli-specified general recombination to give a productive infection.

Coliphages↗

PubMed1976

[Genetic study of bacteriophage phi81. I. Isolation, study of complementation and preliminary mapping of amber-mutants of bacteriophage phi81].

123 Amber mutants of lambdoid bacteriophage phi81 are isolated and distributed into 19 complementation groups. Deletion mapping made possible to locate 5 gene groups on the genetic map of bacteriophage phi81 and to determine a region of possible location of mm' sticky ends on the prophage genetic map. A gene of phage phi81 is localized, which controls the adsorption specificity, and which functional similarity to a respective gene of phage phi80 is demonstrated.

Chromosome Mapping↗

PubMed1975

Bacteriophage-borne enzymes in carbohydrate chemistry. Part I. On the glycanase activity associated with particles of Klebsiella bacteriophage No. 11.

The preparation and use of particles of Klebsiella bacteriophage No. 11 are described. A glycanase activity associated with the viruses catalyses the depolymerization of (alkali-treated) Klebsiella serotype 11 capsular polysaccharide, ultimately to a mixture of oligosaccharides consisting of one or two repeating units. Mainly glucosidic bonds are hydrolysed. The substrate specificity of the viral enzyme has been characterized by using derivatives of serotype-11 polysaccharide, as well as 81 heterologous, bacterial, capsular glycans. It is concluded that the glycanase will (at least) also depolymerize all polysaccharides containing the unsubstituted chain-trisaccharide repeating-unit of its natural substrate.

Aluminum↗

PubMed1975

Structure and synthesis of a lipid-containing bacteriophage. A polynucleotide-dependent polynucleotide-pyrophosphorylase activity in bacteriophage PM2.

A polymerase activity is associated with protein IV, a protein which is associated with the DNA in bacteriophage PM2. The native enzyme unit is probably a dimer. Manganese ions are required for the polymerisation reaction and there is a well-defined Mn2+ optimum at 2.5 mM. The pH optimum is at 8.1, the temperature optimum at 28 degrees C. The activity is a polynucleotide-pyrophosphorylating reaction in the presence of ribo- or deoxyribonucleoside triphosphates. The polymerisation reaction is stimulated in the presence of nuclei- acids or polynucleotides as effectors. The product is not covalently linked to the effector.

Bacteriophages↗