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PubMed1973

Isolation of the bacteriophage lambda receptor from Escherichia coli.

A factor which inactivates the phage lambda can be extracted from Escherichia coli. This factor is a protein and is located in the outer membrane of the bacterial envelope. It is found in extracts of strains which are sensitive to phage lambda, but not in extracts of strains specifically resistant to this phage. We conclude that this factor is the lambda receptor, responsible for the specific adsorption of the phage lambda to E. coli cells. A partial purification of the lambda receptor is described. Inactivation of the phage by purified receptor is shown to be accompanied by the release of deoxyribonucleic acid from the phage.

Adsorption↗
PubMed1974

Time scale for rejoining of bacteriophage lambda deoxyribonucleic acid molecules in superinfected pol+ and polA1 strains of Escherichia coli after exposure to 4 MeV electrons.

The time scale for rejoining of radiation-induced deoxyribonucleic acid (DNA) single-strand breaks was measured in the presence and absence of oxygen. The involvement of DNA polymerase I in this repair process was studied. Formation and rejoining of DNA strand breaks were measured in lambda DNA infecting lysogenic pol(+) and polA1 strains of Escherichia coli irradiated by 4 MeV electrons under identical conditions. Irradiation and transfer to alkaline detergent could be completed in less than 180 ms. The initial yields of DNA strand breaks were identical in pol(+) and polA1 host cells and four- to fivefold higher in the presence of oxygen than in nitrogen anoxia. Evidence for the existence of a very fast repair process, independent of DNA polymerase I, was not found, since no rejoining of radiation-induced DNA strand breaks was observed during incubation from 45 ms to 3 s. In pol(+) host cells most of the strand breaks produced in the presence of oxygen were rejoined within the first 30 to 40 s of incubation, whereas no rejoining could be detected within the same period of time in anoxic cells. Since no rejoining of broken lambda DNA molecules was observed in polA1 host cells, it is concluded that the synthetase activity of DNA polymerase I is involved in the rejoining of DNA breaks induced by radiation in the presence of oxygen.

Coliphages↗
PubMed1975

Intergration of the receptor for bacteriophage lambda in the outer membrane of Escherichia coli: coupling with cell division.

Induction of the synthesis of the receptor for phage lambda is obtained by adding maltose and adenosine 3'-5'-cyclic monophosphate to glucose grown cells of Escherichia coli. Bacteria induced for a short period of time were infected with a high multiplicity of phage lambda , and examined under the electron microscope. Only a fraction of the bacteria were seen to have adsorbed a large number of phage particles. The majority of such bacteria had a constriction indicating formation of a septum, and, in this case, the density of adsorbed particles was highest in the vicinity of the constriction. When found on bacteria showing no sign of septum formation, the adsorbed particles were asymmetrically distributed, one pole of the bacteria being more heavily covered with phage particles than the other. Such asymetrically covered bacteria are believed to have originated from cells which divided during the induction period. The results suggest that the receptor for phage lambda, a protein of the outer membrane, is integrated in the cell envelope during the last quarter of each generation and that the integration process is initiated in the vicinity of the forming septum.

Adsorption↗
PubMed1975

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 of ionic interactions in the stabilization of the outer membrane are discussed.

Antibodies, Bacterial↗
PubMed1975

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 of prophage harbored by each of the ara secondary-site lysogens have been determined. From these secondary-site lysogens it has been possible to generate plaque-forming ara-transducing phage (lambdapara) and defective ara-transducing phage (lambdadara), as well as defective leucine-transducing particles (lambdadleu). The construction and characterization of these lambdaara-transducing phage and their derivatives which carry genetically defined portions of the L-arabinose region are presented.

Arabinose↗
PubMed1975

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 receptor are added to a wild-type strain, transport of maltose at low concentrations is significantly reduced. These results strongly suggest that the phage lambda receptor molecule is involved in maltose transport.

Binding Sites↗
PubMed1975

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 than the entire araC gene were genetically determined and were found to be randomly distributed through the araC gene. The amount of arabinose deoxyribonucleic acid contained on four selected transducing phage was determined by electron microscopy of deoxyribonucleic acid heteroduplexes, providing a physical map of the araC gene. The efficiency with which these phage transduce araC and araB point mutations was found to be approximately proportional to the homology length available for recombination.

Arabinose↗
PubMed1977

Partial purification of the Escherichia coli K-12 mec+ deoxyribonucleic acid-cytosine methylase: in vitro methylation completely protects bacteriophage lambda deoxyribonucleic acid against cleavage by R-EcoRII.

A procedure is described for the partial purification of the deoxyribonucleic acid (DNA)-cytosine methylases controlled by the RII plasmid and by the Escherichia coli mec+ gene. The two enzymes exhibit similar but distinct chromatographic behavior on diethylaminoethyl-cellulose and phosphocellulose. Preliminary studies on the two methylases indicate that they are indistinguishable with respect to their Km for S-adenosylmethionine and their pH (in tris (hydroxymethyl)aminomethane buffer) and NaCl concentration optima. In vitro methylation of various phage lambda DNA substrates by the mec'r RII enzyme modifies the DNA to a form that is completely resistant to double-stranded cleavage by the RII restriction endonuclease (R-EcoRII). These results are consistent with our earlier proposal that the mec8ethylase recognizes RII host specificity sites.

Coliphages↗
PubMed1979

Mapping of ilvO loci of Escherichia coli K-12 with bacteriophage lambda dilv.

A set of lambda dilv phage have been used in a deletion mapping procedure to determine the location of two previously characterized ilvO alleles. In contrast to earlier conclusions derived from three-factor crosses and episome-shortening techniques with phage P1, the order found is ilvG-ilvO-ilvEDA. A three-factor cross with phage P1 is described that is not consistent with this location for an ilvO allele. Further analysis of this particular three-factor cross revealed than an artifact attributable to a mutual syntrophism had skewed the apparent frequency of inheritance of the ilvO locus. The role of mutual syntrophism is discussed as a source of mapping errors for the ilvO locus. The value of this set of lambda dilv phage and this mapping procedure for obtaining comparatively unambiguous data on the locations of the ilv structural and regulatory genes is demonstrated.

Acetolactate Synthase↗
PubMed1979

Receptor for bacteriophage lambda of Escherichia coli forms larger pores in black lipid membranes than the matrix protein (porin).

The receptor for phage lambda in Escherichia coli was isolated by cholate extraction and purified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Protein bands corresponding to the monomer and the dimer were eluted from the gel and tested for their activity to inactivate phage lambda and to form pores in black lipid membranes. It was found that only the dimer inactivated phage lambda, whereas both the monomer and the dimer were active in forming pores. The pore characteristics were similar to those exhibited by the matrix protein (porin) (R. Benz, K. Janko, W. Boos, and P. Läuger, Biochim. Biophys. Acta 511:305--319, 1978). In comparison, the lambda receptor showed a somewhat higher degree of cation specificity, and its pore size was larger. Assuming that the thickness of the outer membrane is 7.5 nm and that the pore is an ideal hydrophilic channel, the pore diameter in vivo was estimated to be 1.6 nm for the lambda receptor and 1.2 nm for the matrix protein.

Bacterial Proteins↗
PubMed1979

Introduction of bacteriophage lambda into cells of Klebsiella aerogenes.

We have shown that a mutation in the cro gene of phage lambda greatly reduces zygotic induction. This observation has allowed us to move this phage on an episome into cells of Klebsiella aerogenes where it grows as well as in cells of Escherichia coli. This technique should allow the introduction of various derivatives of lambda into any organism which is able to receive deoxyribonucleic acid from E. coli.

Coliphages↗
PubMed1972

Isolation and properties of rex - mutants of bacteriophage lambda.

Twenty-five rex(-) mutants of phage lambda have been isolated. Three of the mutants, including one amber mutant, map at three distinct sites within the rex region of the lambda genetic map. The existence of the amber mutant provides further evidence that rex and cI are distinct genes, since it seems to be identical to wild-type lambda in its ability to establish or maintain lysogeny.

Coliphages↗
PubMed1973

Prophage induction by high temperature in thermosensitive dna mutants lysogenic for bacteriophage lambda.

High-temperature treatment of thermosensitive dna mutants lysogenic for phage lambda leads to prophage induction and release of phage (at the permissive temperature) in elongation-defective mutants of the genotypes dnaB, dnaE, and dnaG. In initiation-defective mutants no prophage induction occurs at 42 C in mutants of the genotype dnaA, whereas with a dnaC mutant as well as with strain HfrH 252 (map position not yet known) phages are released at 42 C. DNA degradation at the replication fork at 42 C is observed in all dnaB(lambda) mutants tested, but not in mutants of the genotypes dnaE(lambda) and dnaG(lambda). Therefore, degradation of replication fork DNA is not a prerequisite for prophage induction.

Coliphages↗
PubMed1974

Role of genetic recombination in DNA replication of bacteriophage lambda. I. Genetic characterization of the delta gene.

We describe the isolation and genetic characterization of point mutations in gene delta, including a temperature-sensitive mutation (del(206)). Genetic methods enable the extraction of a delta mutation from the triple mutant (del,red,gam) and the construction of new genotypes, including del,red and del,gam double mutants. Tests of plating efficiency indicate gene delta is essential for normal phase growth on the polA host. The possible association of delta in a system involving alpha, beta, and gamma is considered.

Coliphages↗
PubMed1974

Role of genetic recombination in DNA replication of bacteriophage lambda. II. Effect in DNA replication by gene delta.

We have studied the effect of delta mutations in phage lambda on DNA synthesis as assayed by the accumulation of lambda DNA in infected cells. We find that delta mutants appear to generate somewhat less DNA than lambda(+) in a rec(+) host, suggesting the wild-type delta gene may act in DNA replication. An additional clue to delta function arises if replication is measured in the gamma-negative situation where concatemer formation is abortive. In this situation, the wild-type delta gene has an "inhibitory" effect on replication. A similar inhibitory effect on replication due to delta is observed after infection of P(2) lysogens. We conclude from these studies that the delta gene may act with alpha, beta, and gamma genes, possibly in a process affecting DNA replication.

Coliphages↗
PubMed1975

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 phage growth was not investigated. Most Mal+ strains of Shigella have lambda receptor, whereas most Mal- strains do not have it. Synthesis of the lambda receptor in Shigella is thus presumably controlled by the positive regulator gene of the maltose regulon as is the case in E. coli K-12. Phage lambda adsorbs on many Mal+ strains of Shigella and even yields plaques on some of them, although at a low frequency. No lambda receptor activity could be found in extracts of several strains of Salmonella and Levinea.

Adsorption↗
PubMed1977

Identification of the site of interruption in relaxed circles producing during bacteriophage lambda DNA circle replication.

The DNA that accumulates in the lambda infection restricted to the early (circular) stage of replication consists of approximately two-thirds covalently closed circles and one-third relaxed circles bearing a single interruption in either strand of the duplex. The latter molecules are presumed to be a unique class in that the interruption is not repairable by DNA polymerase and ligase. Preferential radioisotopic labeling of the region immediately adjacent to the interruption, followed by hybridization to sheared fragments of the lambda chromosome with varying guanine plus cytosine content, suggested that the nick resides at the position of the mature molecular ends of the lambda chromosome. Digestion of the labeled molecules with restriction enzymes and reconstruction experiments in which Hershey circles were generated by annealing of interrupted strands isolated from the relaxed circles support this interpretation. The results indicate that the relaxed circles consist of a population containing one interruption in either of the two strands of the duplex jointly representing the two "nicks" contained in Hershey circles (in which the cohesive ends are annealed). These molecules could result from the inability of the maturation function to make the required staggered endonucleolytic cuts when the DNA substrate is a monomeric circle rather than a multimeric linear molecule. Alternatively, this interruption could be the result of an endonucleolytic cutting event critical to DNA replication.

Chromosome Mapping↗