Bacteriophage

J Supramol Struct, 1979, 10(4), 457 - 65
Structure of the DNA binding cleft of the gene 5 protein from bacteriophage fd; McPherson A et al.; The structure of the gene 5 DNA unwinding protein from bacteriophage fd has been solved to 2.3-A resolution by X-ray diffraction techniques . The molecule contains an extensive cleft region that we have identified as the DNA binding site on the basis of the residues that comprise its surface . The interior of the groove has a rather large number of basic amino acid residues that serve to draw the polynucleotide backbone into the cleft . Arrayed along the external edges of the groove are a number of aromatic amino acid side groups that are in position to stack upon the bases of the DNA and fix it in place . The structure and binding mechanism as we visualize it appear to be fully consistent with evidence provided by physical-chemical studies of the protein in solution.

Dev Biol Stand, 1979, 42, 87 - 91
Construction of hybrid viruses in vitro and their possible use for the production of specific viral or cellular proteins; Yaniv M; The use of plasmid and bacteriophage vectors for cloning of DNA segments from procaryotes and eucaryotes is described . A similar approach is being developed with DNA viruses like simian virus 40 or adenovirus 2 . Such hybrid viruses may permit the amplification of specific genes and the overproduction of the corresponding proteins.

J Virol, 1979 Jan, 29(1), 322 - 7
Gene D5 product of bacteriophage T5: DNA-binding protein affecting DNA replication and late gene expression; McCorquodale DJ et al.; Gene D5 is not only necessary for replication of bacteriophage T5 DNA and for shutoff of expression of some early genes, but has been found to be necessary also for the expression of late T5 genes . The polypeptide product of gene D5 has been identified, an intragenic map of gene D5 has been constructed, and the direction of transcription of gene D5 has been established . The polypeptide coded by gene D5 has been shown to be a DNA-binding protein with affinity for both double- and single-stranded DNA.

Z Allg Mikrobiol, 1979, 19(5), 325 - 32
{Effect of the detergent Metaupon on replication of various phages}; Menzel G et al.; As several other surfactants do, the detergent Metaupon acts on the multiplication of bacteriophages . We investigated the influence of Metaupon on the phages phi and lambda, the cyanophage LPP-1, and the RNA-phages f 2, M 12, and Q beta by means of the agar diffusion test, pour plate test, adsorption test, and one-step growth test . The action of Metaupon on the free phages was also tested . Metaupon inhibits the formation of plaques by the phages with exception of lambda . With the phages f 2 and M 12 the substance increases the amount of plaques depending on concentration . The main mode of action of Metaupon was found to be the inhibition of the adsorption of the phages to the host cells . Only in the case of phi 105 free phages were inactivated.

Genetika, 1979, 15(10), 1719 - 23
{Characteristics of bacteriophage lambda and P1 modification-restriction in Escherichia coli strains controlled by factor R124}; Skavronskaia AG et al.; The specifities of restriction of bacteriophages P1 and lambda controlled by R plasmids in Escherichia coli have been investigated . The isogenic strains harbouring the plasmids pAS26 coding for restriction endonuclease R.EcoRI, R245 coding for restriction endonuclease R.EcoRII and and R124 have been investigated in the present work . Modification-restriction controlled by R124 has been found to differ in specificity from those controlled by R245 and pAS26 . Frequencies of restriction of bacteriophages P1vir and lambdavir specified by R124 pasmid differ from the frequencies in the strains harbouring pAS26 and R245 plasmids as well . The difference is due to the specifity of restriction-modification controlled by R124 plasmid . The data obtained are consistent with the determination of R124 specified restriction-modification activity as a novel one designated R.EcoRIII.

Genetika, 1979, 15(8), 1351 - 9
{Transposition of the deo operon structural genes in Escherichia coli K-12 to plasmid RP4 using bacteriophage mu}; Grishchenkov VG et al.; Transposition of the structural genes of the deo operon of Escherichia coli K-12 into plasmid RP4 by means of temperate bacteriophage Mu was carried out . Some variants of composite RP4-deo-Mu plasmids were obtained and the expression of the deo genes integrated into the RP4 plasmid genome was studied . It was shown that the expression of these genes remains under the control of the chromosomal regulatory genes (deoR and cytR); although the activity of thymidine phosphorilase in the strain E . coli which contains hybrid plasmid is 4-6 fold greater than that in strains of E . coli with chromosomal localization of the deo operon.

Genetika, 1979, 15(7), 1191 - 8
{Hybrid plasmid pSD1 containing the immunity region of bacteriophage lambda}; Dikarev SD et al.; Hybrid plasmid pSD1 carrying the immunity region of the coliphage lambda and bio operon have been obtained by means of studying the efficiency of transcription DNA fragments in the plasmid RSF2124 . The molecular weight of this plasmid is 17.2 Md . The growth inhibition of phage lambdavir has been observed in cells carrying the new hybrid plasma . The properties of the plasmid pSD1 and probable reasons of the growth inhibition of phage lambdavir are discussed . The hybrid plasmid pSD2 carrying genes R, A and J of phage lambda has been constructed on the basis of the plasmid RSF2124 . There are cohesive ends in this plasmid which make possible its packing in the phage lambda head . Hybrid plasmid pSD3 carrying genes P and Q of phage lambda has also been constructed.

Cold Spring Harb Symp Quant Biol, 1979, 43 Pt 1, 165 - 78
Functional analysis of the replicator structure of lambdoid bacteriophage DNAs; Hobom G et al.; In our hybrid-plasmid reconstruction analysis of lambda (lambdoid) DNA signal structures involved in phage DNA replication, we have detected a dual system alternatingly able to initiate a first primer-RNA synthesis . Both of them--the major, primase-dependent ori system and the minor and usually suppressed, RNA-polymerase-dependent oop system--act in conjunction with a common signal structure for inception of DNA synthesis . It appears that in situations such as this, where one has to deal with the existence of regular as well as backup systems serving the same function, straightforward conclusions are no longer possible in their genetic analysis . For example, even though the oop-DNA segment can be deleted entirely from bacteriophage lambda DNA without disturbing its ability to replicate, it may not be valid to conclude that the oop system has no function in DNA replication . Dual systems of this type or organization in general have also been observed previously for some other replicons such as the R-factors R6-5 and R6K (Timmis et al . 1978; Crosa et al., this volume) or the F factor (Helinski et al., this volume), and they may be more common than presently expected.

Rev Chir Orthop Reparatrice Appar Mot, 1979 Jan-Feb, 65(1), 33 - 7
{Bacteriophage therapy of septic complications of orthopaedic surgery (author's transl}; Lang G et al.; Seven septic cases have been treated by bacteriophage; two infections after insertion of a hip prosthesis, two septic arthritis of the knee, one osteomyelitis of the tibia, one septic non-union of the femur and one septic complication following Harrington rodding . Only specific phages were used in association with several types of surgical procedure . The technique of treatment is described . All cases were long-term infections with resistant organisms . Results were good in five, fair in one and one case was a failure . It is concluded that phage therapy may be helpful in the treatment of long-term infections.

Z Naturforsch {C}, 1979 Jan-Feb, 34(1-2), 162 - 4
Methylmercury-induced sedimentation heterogeneity of T7 bacteriophage DNA; Gruenwedel DW et al.; Single-stranded and methylmercurated T7 DNA is composed of two species as evidenced from the sedimentation pattern displayed during band-sedimentation in self-generating density gradients as well as during equilibrium-sedimentation in CS2SO4 density gradients . Under the given experimental conditions, viz., at pH 9.18 and in presence of 0.1 mM CH3HgOH, the two species band in CS2SO4 with a density difference of 0.008 g/ml . The ratio of the sedimentation coefficients of the two species is sw, 20 (fast)/sw, 20 (slow) = 1.63 at pH 9.18 and in presence of 1.6 mM CH3HgOH . Both native and denatured T7 DNA behave as monodisperse systems in the absence of CH3HgOH.

Rev Chir Orthop Reparatrice Appar Mot, 1979 Jan-Feb, 65(1), 33 - 7
{Bacteriophage therapy of septic complications of orthopaedic surgery (author's transl)}; Lang G et al.; Seven septic cases have been treated by bacteriophage ; two infections after insertion of a hip prosthesis, two septic arthritis of the knee, one osteomyelitis of the tibia, one septic non-union of the femur and one septic complication following Harrington rodding . Only specific phages were used in association with several types of surgical procedure . The technique of treatment is described . All cases were long-term infections with resistant organisms . Results were good in five, fair in one and one case was a failure . It is concluded that phage therapy may be helpful in the treatment of long-term infections.

Acta Biol Med Ger, 1979, 38(11-12), 1627 - 37
Studies on the regulation of igm immune response . VII . changes in the affinity of antibodies and cell receptors after immunization with the T-cell independent antigen DNP-Ficoll; Fiebig H et al.; A/J-mice immunized by a single injection with DNP21-Ficoll respond on the humoral level exclusively with IgM antibodies . The intrinsic association constants (K0) of IgM anti-DNP to monovalent hapten E-DNP-L-lysine are within the range of 105-106 M-1 and do not change significantly during the immune response . On the other hand, the functional association constants (KF) of pentameric IgM to multivalent DNP-T4 bacteriophage increase from 1010 M-1 at 3rd day up to 1012 M-1 at 8th day . Subsequently, a decrease of KF to 1011 M-1 can be observed . This rise and fall of the affinity of IgM antibodies of multivalent DNP-conjugate can be detected at the cellular level also by inhibition of plaque formation . The concentration of DNP15-BSA needed for 50% inhibition of plaque formation (I50) decreases from second day to 8 th day by 4 orders, which represents a strong increase of functional affinity . In contrast, the I50 of E-DNP-L-lysine slightly decreases only until day 4 and does not change until day 21 . the inhibition of rosette formation by mono- and multivalent ligands was used to study the affinity of lymphocyte receptors . In the course of immunization antigen-binding cells carrying receptors with increasingly higher affinity for multivalent DNP-conjugates occur . These results are discussed with regard to the importance of functional affinity of lymphocyte receptors for the antigen-driven selection of high affinity anti-DNP-cell clones producing IgM antibodies.

Acta Biol Med Ger, 1979, 38(11-12), 1615 - 25
{Regulations of IgM immune response . IV . Effect of the hapten: carrier ratio and the nature of the carrier on the intrinsic and functional affinity of carp DNP-antibodies}; Fiebig H et al.; Carp anti-DNP antibodies were raised by various DNP-carrier conjugates . Their intrinsic affinity (K0) to monovalent E-DNP-L-lysine and functional affinity (DF) for binding to the multivalent DNP-T4 bacteriophages were determined . The functional affinity of antibodies elicited by T-cell-dependent DMPn-HSA (n = 3, 15, 33) is relatively high (KF):1010-1012 M-1) . These KF values increase more than K0 during the immune response . The functional affinity is dependent on the molar KNP: HSA ratio . The mediate coupled DMP15-HSA elicits antibodies with the highest functional affinity . Carps immunized with T-cell-independent DNP-conjugates synthesize antibodies which have similar K0 as the antibodies elicited with DNP-HSA . However, the KF-values are in the range from 107 to 1010 M-1 only . The KF of antibodies raised with DNP-BA are 103-104 fold, those of DNP-S III and DNP-Ficoll elicited are only 4 . 101 to 4,7 . 102 fold higher than their corresponding K0-values . This means that these antibodies are not very effective in binding the multivalent DNP-T4 . Specifically purified antibodies have also such low functional affinities . These strong differences in the functional affinity of carp DNP-antibodies elicited by T-cell dependent and independent DNP-conjugates are discussed with regard to stimulation of different B-cell subpopulations.

Ultramicroscopy, 1979, 4(1), 91 - 6
The reconstruction of a helical structure from projections applied to a phage tail; Cremers AF et al.; A procedure has been described for 3 D-image reconstruction for helical biological structures, if more than one projection will be required to determine the contributing helical density-waves . The method was tested with a helical protein aggregate derived from a bacteriophage . The results showed the feasibility of the proposed scheme and yielded a low resolution picture (about 2.5 nm) of the protein structure.

Mol Gen Genet, 1979, 172(3), 295 - 301
Characterization of an amber suppressor in Pneumococcus; Gasc AM et al.; Partial revertant has been isolated, with resistance to aminopterin intermediate between wild type and mutant . This phenotype is the result of a mutation at a gene unlinked to the amiA locus . This suppressor mutation (su+) has no phenotypic characteristics by itself except a slow growth . 9 amiA mutants (belonging to 6 sites) are affected by su+ out of the 30 investigated mutants (i.e . 22 sites) . The efficiency of suppression is site dependent . Two sites out of 14 mutants belonging to the thymidylate synthetase gene are suppressible . Thymidylate synthetase activity is partially restored by su+ . Optochin mutants can also be suppressed . Thus su+ is not gene specific but site specific . Moreover when the str-41 allele conferring resistance to streptomycin is introduced by transformation, the suppression effect is restricted . All these properties are characteristic of an informational suppressor . The t-RNA extracted from the suppressor strain su+ but not the wild type restored the synthesis of coat protein coded by RNA from an amber mutant of bacteriophage f2 . Attempts to detect ochre suppression activity gave negative results . It is suggested that the su+ gene is amber specific . Thus su+ can provide insight into the nature of suppressible mutations which should be point mutations . Both low efficiency and high efficiency mutants are affected by su+; this is additional evidence that both categories contain point mutations.

Z Allg Mikrobiol, 1979, 19(7), 473 - 80
{Host range relationship of bacteriophages T3 and T7 with Escherichia coli K 12 strains}; Kruger DH et al.; The closely related phages T3 and T7 exhibit different growth patterns on Escherichia coli W hosts cells (E . coli K12 derivatives) . T7 grows normally while T3 does not adsorb . T3hw mutants displaying a T7-like host range were isolated and described.

Z Allg Mikrobiol, 1979, 19(6), 391 - 6
{Effect of temperature on RNA synthesis in Escherichia coli CRT 266 (dna Bts) following infection with bacteriophage T3}; Brux B et al.; 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-specific RNA synthesis . The maximum of T3-induced RNA synthesis could be observed between 7 min and 3 min depending on the temperature during infection . The inability to form T3-specific RNA after infection of E . coli CRT 266 at nonpermissive temperatures may be a cause for the absence of the formation of T3 phages and lysis of the host cells.

Acta Microbiol Pol, 1979, 28(3), 203 - 11
Aggregation deficient Escherichia coli K-12 female mutants with altered lipopolysaccharide; Heleszko H et al.; Two F- mutants deficient in conjugation with F-donors have been characterized . They map at about 83 minut position, show resistance to T3 and T7 bacteriophages, and form mating aggregates in the liquid medium with lowered efficiency . Mutants have no detectable alterations in their outer membrane protein composition.

Mol Gen Genet, 1979, 172(3), 303 - 12
Physical mapping of the restriction fragments obtained from bacteriophage T4 dC-DNA with the restriction endonucleases SmaI, KpnI and BglII; Kiko H et al.; The cytosine-containing DNA of a mutant of bacteriophage T4 was digested with restriction endonucleases SmaI, KpnI and BglII producing 5, 7 and 13 fragments respectively . Complete physical maps of the T4 genome were constructed with the enzymes SmaI and KpnI and an almost complete map with the enzyme BglII.

Mol Gen Genet, 1979, 172(3), 329 - 37
Aberrant immunity behaviour of hybrid lambda imm21 phages containing the DNA of ColE1-type plasmids; Windass JD et al.; Hybrid lambda and lambda imm21 bacteriophages carrying various ColE1-type plasmids have been constructed in vitro . The lambda imm21/plasmid recombinants display aberrant immunity behaviour, giving clear plaques under conditions where the parental phages give turbid ones and being able to grow on homoimmune lysogens . lambda imm lambda/plasmid recombinants show no such unusual behaviour . Studies with hybrids of a lambda imm21 cITS phage carrying pMB9 DNA showed the operation of the plasmid's replication system to be the basic cause of the aberrant immunity behaviour . The plasmid replication system could act as a complete alternative to the phage system during vegetative phage growth . The probable reason that lambda imm21 phages show such altered phenotypes when carrying a functional plasmid replication origin, whereas lambda imm lambda and lambda imm434 (Mukai et al., 1978) phages do not, is the relative ease of titration of the phage 21 repressor to allow transcription from pR21 . Various uses are considered for the altered phenotypic behaviour of lambda imm21/ColE1-type plasmid hybrids.

Mol Gen Genet, 1979, 172(3), 271 - 9
Bacteriophage SPP1 polypeptides synthesized in infected minicells and in vitro; Mertens G et al.; Minicells produced by B . subtilis CU403divIVB1 and infected by SPP1 synthesize at least 46 polypeptides which can be separated by polyacrylamide gel electrophoresis . These polypeptides represent the expression of 86% of the SPP1 genome's coding capacity . Infection of minicells by sus mutants and deletion mutants of SPP1 has permitted a correlation of genetic location with gene product and has shown that SPP1 normally synthesizes at least 8 non-essential polypeptides . Restriction fragments of SPP1 produced by EcoRI digestion of SPP1 DNA have been purified and used as template DNA in a coupled transcription/translation system derived from E . coli to determine the polypeptides encoded by the individual fragments . SPP1 expression in minicells differs from SPP1 expression in nucleated cells (Esche, 1975) in that late syntheses are not dependent on phage DNA replication in infected minicells.

J Supramol Struct, 1979, 11(2), 139 - 45
NMR of fd coat protein; Cross TA et al.; The conformations of the major coat protein of a filamentous bacteriophage can be described by nuclear magnetic resonance spectroscopy of the protein and the virus . The NMR experiments involve detection of the 13C and 1H nuclei of the coat protein . Both the 13C and 1H nuclear magnetic resonance (NMR) spectra show that regions of the polypeptide chain have substantially more motion than a typical globular protein . The fd coat protein was purified by gel chromatography of the SDA solubilized virus . Natural abundance 13C NMR spectra at 38 MHz resolve all of the nonprotonated aromatic carbons from the three phenylalanines, two tyrosines, and one tryptophan of the coat protein . The alpha carbons of the coat protein show at least two different classes of relaxation behavior, indicative of substantial variation in the motion of the backbone carbons in contrast to the rigidity of the alpha carbons of globular proteins . The 1H spectrum at 360 MHz shows all of the aromatic carbons and many of the amide protons . Titration of a 1H spectra gives the pKas for the tyrosines.

J Bacteriol, 1979 Jan, 137(1), 556 - 67
Bacteriophage-associated gene transfer in pneumococcus: transduction or pseudotransduction?
Porter RD, Shoemaker NB, Rampe G, Guild WR.
Lysates of pneumococcal phage PG24 transferred genes from one host to another in a process with many of the properties of generalized transduction, in that the host genes were packaged in DNase-resistant particles that closely resembled infectious phage in physical properties, adsorbed to the recipient cells like phage, and were inhibited by antisera to the phage and by trypsin . However, phage processes did not complete the transfer of host DNA as they did phage DNA . Instead, gene transfer required development of competence and entry of the host DNA by the endonuclease-dependent pathway used for transforming and transfecting DNA . This process often occurred on the assay plate hours after adsorption of the particles to the cells, and the transfer was DNase sensitive if challenged at this time . Phenotypic expression was therefore also delayed . The product of entry was like that in transformation, a single strand of DNA that integrates by formation of a hex-sensitive donor-recipient heteroduplex . Whether this gene transfer process is unique to this system or is only the first one described is not clear . The term "pseudotransduction" may be useful in calling attention to its unexpected features . The DNA of PG24 phage has anomalous physical properties reflecting unusual bases.

Biochemistry, 1978 Dec 26, 17(26), 5695 - 705
Transcription of histone-covered T7 DNA by Escherichia coli RNA polymerase; Williamson P et al.; Purified core histones (H2A, H2B, H3, and H4) and bacteriophage T7 DNA have been reconstituted to form a nucleoprotein complex, and the properties of this complex as a template for transcription by Escherichia coli RNA polymerase have been studied . At low ionic strength, RNA chain elongation rates are slow, and the chains produced even after long incubation are short . At higher salt concentrations, chain-elongation rates approach those on naked DNA . Since the salt concentrations used are not in themselves sufficient to dissociate the histones from the DNA, some mechanism must exist that permits passage of the polymerase through histone-covered regions.

J Biol Chem, 1978 Dec 25, 253(24), 8941 - 8
A steady state assay for the RNA polymerase initiation reaction; McClure WR et al.; A new assay yielding mechanistic information on the initiation reaction of Escherichia coli RNA polymerase has been developed . It was found to be useful in characterizing the promoters of bacteriophage DNA templates . The binding of the first two triphosphates in an RNA sequence was determined to be equilibrium ordered with ATP binding first followed by UTP on the lambda promoters PL . and PR . The products resulting from phosphodiester bond formation, pppApU and PPi, dissociated rapidly in the absence of the other triphosphates required for RNA synthesis . The resulting steady state conversion of ATP and UTP into pppApU was the basis for the new assay . The rate-limiting step in the initiation reaction was not precisely determined, but it was argued not to be entirely the release of product . The Zn2+ chelator, 1,10-phenanthroline, was partially characterized and found to be an uncompetitive inhibitor of ATP in the reaction (Ki = 100 micrometer) . The unique advantage of this steady state assay is that several steps in the RNA initiation process are amplified kinetically and thus can be examined separately with techniques applicable to any other two-substrate, two-product enzyme reaction.

Science, 1978 Dec 22, 202(4374), 1284 - 9
Cloning human fetal gamma globin and mouse alpha-type globin DNA: characterization and partial sequencing; Smithies O et al.; Two globin-related clones isolated from collections of bacteriophages containing unfractionated Eco RI fragments of human and mouse DNA were characterized . Charon3AHs51.1Hbgamma includes 2.7 kilobase pairs of human DNA containing a large part of a fetal gamma globin chain structural gene; Charon 3AMm30.5 includes 4.7 kilobase pairs of mouse DNA related to alpha globin . The human fetal gamma globin gene has within its coding region two intervening sequences of noncoding DNA, IVS 1 and IVS 2, of approximately 1-0 and 900 base pairs . Sequence IVS 1 is located at the position of one of the two intervening sequences occurring in adult globin genes; IVS 2 is located at the position of the other.

Science, 1978 Dec 22, 202(4374), 1279 - 84
Cloning human fetal gamma globin and mouse alpha-type globin DNA: preparation and screening of shotgun collections; Blattner FR et al.; Shotgun collections of Charon 3A bacteriophages containing Eco RI fragments of human and mouse DNA were constructed with the use of in vitro packaging . Plaques were screened by hybridization, and globin-specific clones were isolated from both human (Charon 3AHs51.1) and mouse (Charon 3AMm30.5) . The fragments cloned were detected in unfractionated genomic DNA by the Southern method of hybridization.

J Biol Chem, 1978 Dec 10, 253(23), 8390 - 9
Determination of the first half of the coat protein cistron of bacteriophage Qbeta as an application of a mapping procedure for RNA fragments; Escarmis C et al.; A method is described to classify, in regard to their location within the genome, fragments obtained by partial cleavage of 32P-labeled bacteriophage Qbeta RNA . The location of many fragments suitable for sequence analysis could be established using as markers 29 large RNase T1-resistant oligonucleotides with known map positions . Applying this method four fragments originating from the coat protein cistron were isolated and analyzed . The sequence of a segment of 239 nucleotides located immediately adjacent to the initiation triplet was determined to be G-C-A-A-A-A-U-U-A-G-A-G-A-C-U-G-U-U-A-C-U-U-U-A-G-G-U-A-A-C-A-U-C-G-G-G-A-A-A-G-A-U-G-G-A-A-A-A-C-A-A-A-C-U-C-U-G-G-U-C-C-U-C-A-A-U-C-C-G-C-G-U-G-G-G-G-U-A-A-A-U-C-C-C-A-C-U-A-A-C-G-G-C-G-U-U-G-C-C-U-C-G-C-U-U-U-C-A-C-A-A-G-C-G-G-G-U-G-C-A-G-U-U-C-C-U-G-C-G-C-U-G-G-A-G-A-A-G-C-G-U-G-U-U-A-C-C-G-U-U-U-C-G-G-U-A-U-C-U-C-A-G-C-C-U-U-C-U-C-G-C-A-A-U-C-G-U-A-A-G-A-A-C-U-A-C-A-A-G-G-U-C-C-A-G-G-U-U-A-A-G-A-U-C-C-A-G-A-A-C-C-C-G-A-C-C-G-C-U-U-G-C-A-C-U-G-C-A-A-A-C-G-G-U-U-C-U-U-Gp . The primary structure and the secondary structure model derived from it did not provide any evidence of homology with the corresponding RNA region of bacteriophage MS2.

J Biol Chem, 1978 Dec 10, 253(23), 8400 - 5
A hybridization procedure for the isolation of specific RNA segments applied to the analysis of bacteriophage Qbeta RNA; Shapira A et al.; A method for the isolation of RNA fragments originating from defined regions of bacteriophage Qbeta RNA minus strands is described . Large RNase T1 oligonucleotides were isolated on a preparative scale from Qbeta RNA . The nucleotide sequences (13 to 26 nucleotides) and map positions of these oligonucleotides were known from previous work (Billeter, M . A . (1978) J . Biol . Chem . 253, 8381-8389) . After addition of AMP residues (50 in the average) using terminal adenylate transferase, these pure oligonucleotides were hybridized to 32P-labeled Qbeta RNA minus strands synthesized in vitro . Fragments in the size range of 100 to 500 nucleotides were then generated by partial digestion with RNase T1 . Fragments hybridized to such oligonucleotides were recovered by chromatography on poly(U)-Sephadex and then resolved according to their size by polyacrylamide gel electrophoresis . The specificity and reproducibility of the method as well as its suitability for the sequence analysis of Qbeta RNA was verified by using in particular a linker oligonucleotide derived from a Qbeta RNA region near the 3' end . The sequence catalogues of the RNase T1 and RNase A oligonucleotides of two fragments isolated in this way, 202 and 310 nucleotides in length, were established and all fragments isolated were shown to contain a sequence complementary to the linker oligonucleotide.

J Biol Chem, 1978 Dec 10, 253(23), 8381 - 9
Sequence and location of large RNase T1 oligonucleotides in bacteriophage Qbeta RNA; Billeter MA; Twenty-nine oligonucleotides, 11 to 26 nucleotides in length, arising by complete RNase T1 digestion of bacteriophage Qbeta RNA and isolated by two-dimensional polyacrylamide gel electrophoresis, were sequenced . Their location within the genome was established with two methods . (a) In vitro synthesis of Qbeta RNA plus strands was started synchronously, using minus strands as template and nucleoside {alpha-32P}triphosphates as substrate; after various times, the reaction was stopped and the length of the products formed was correlated with their content of T1 oligonucleotides . (b) Qbeta {32P}RNA was elongated with poly(A) using terminal riboadenylate transferase; after mild treatment with alkali the fragments were fractionated by size and the poly(A)-containing molecules of each size class were isolated by chromatography on poly(U)-Sephadex and assayed for T1 oligonucleotides . The oligonucleotides in the 5' region were localized more precisely with method a, those near the 3' end with method b; in the middle region, the results of the two sets of analyses confirmed each other . The use of these oligonucleotides in the sequence determination of Qbeta RNA is discussed.

Nucleic Acids Res, 1978 Dec, 5(12), 4495 - 503
Nucleotide sequence of bacteriophage fd DNA; Beck E et al.; The sequence of the 6,408 nucleotides of bacteriophage fd DNA has been determined . This allows to deduce the exact organisation of the filamentous phage genome and provides easy access to DNA segments of known structure and function.

Eur J Biochem, 1978 Dec, 92(2), 589 - 96
Structure and synthesis of a lipid-containing bacteriophage . Total reconstitution of bacteriophage PM2 in vitro; Schafer R et al.; 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.

Eur J Biochem, 1978 Dec, 92(2), 579 - 88
Structure and synthesis of a lipid-containing bacteriophage . Dissociation of bacteriophage PM2 into its morphological subunits; Schafer R et al.; The lipid-containing bacteriophage PM2 was dissociated stepwise in 1 M NcCl (pH 7.2)with increasing urea concentrations . In 2 M urea the following substructures could be identified: (a) a nucleocapsid containing all of the viral lipid, the DNA, proteins III and IV, plus a fraction of protein II, and (b) a second substructure respresenting particles which contained all viral elements except protein I, the spike protein . In 4 M urea the viral nucleocapsid containing all of proteins III and IV, the DNA, plus a fraction of protein II, was isolated . Upon increasing the urea concentration further, this nucleocapsid is stable up to 8.5 M urea; in 9 M urea protein III was partly dissociated from the nucleocapsid . The nucleocapsid in 4--8.5 M urea is stabilized by the addition of 0.1--3 M NaCl but dissociates if the NaCl concentration is less than 0.1 M . The nucleocapsid was also dissociated in 4--8.5 M urea at pH 4.5 . The nucleocapsid structures and some intermediate morphological subunits have been analysed by physical methods, enabling us to draw some conclusions about the structure and hydration of the virus.

J Virol, 1978 Dec, 28(3), 917 - 28
Electrophoresis of bacteriophage T7 and T7 capsids in agarose gels; Serwer P et al.; Agarose gel electrophoresis of the following was performed in 0.05 M sodium phosphate-0.001 M MgCl2 (pH 7.4): (i) bacteriophage T7; (ii) a T7 precursor capsid (capsid I), isolated from T7-infected Escherichia coli, which has a thicker and less angular envelope than bacteriophage T7; (iii) a second capsid (capsid II), isolated from T7-infected E . coli, which has a bacteriophage-like envelope; and (iv) capsids (capsid IV) produced by temperature shock of bacteriophage T7 . Bacteriophage T7 and all of the above capsids migrated towards the anode . In a 0.9% agarose gel, capsid I had an electrophoretic mobility of 9.1 +/- 0.4 X 10(-5) cm2/V.s; bacteriophage T7 migrated 0.31 +/- 0.02 times as fast as capsid I . The mobilities of different preparations of capsid II varied in such gels: the fastest-migrating capsid II preparation was 0.51 +/- 0.03 times as fast as capsid I and the slowest was 0.37 +/- 0.02 times as fast as capsid I . Capsid IV with and without the phage tail migrated 0.29 +/- 0.02 and 0.42 +/- 0.02 times as fast as capsid I . The results of the extrapolation of bacteriophage and capsid mobilities to 0% agarose concentration indicated that the above differences in mobility are caused by differences in average surface charge density . To increase the accuracy of mobility comparisons and to increase the number of samples that could be simultaneously analyzed, multisample horizontal slab gels were used . Treatment with the ionic detergent sodium dodecyl sulfate converted capsid I to a capsid that migated in the capsid II region during electrophoresis through agarose gels . In the electron microscope, most of the envelopes of these latter capsids resembled the capsid II envelope, but some envelope regions were thicker than the capsid II envelope.

J Virol, 1978 Dec, 28(3), 895 - 904
Bacteriophage phi29 terminal protein: its association with the 5' termini of the phi29 genome; Ito J; The location of the protein bound to bacteriophage phi29 DNA has been studied with restriction endonucleases, exonucleases, and polynucleotide kinase . The protein is invariably associated with the two terminal DNA fragments generated by restriction endonucleases . The phi29 DNA prepared with or without proteinase K treatment is resistant to the action of the 5'-terminal-specific exonucleases, lambda-exonuclease and T7 exonuclease . The phi29 DNA is also inaccessible to phosphorylation by polynucleotide kinase even after treatment with alkaline phosphatase . On the other hand, phi29 DNA is sensitive to exonuclease III, and the 3' termini of the DNA can be labeled by incubating with alpha-{32P}ATP and terminal deoxynucleotidyl transferase . The protein remains associated with the phi29 DNA after treatment with various chaotropic agents, including 8 M urea, 6 M guanidine-hydrochloride, 4 M sodium perchlorate, 2 M sodium thiocyanate, and 2 M LiCl . These results are consistent with the notion that the protein is linked covalently to the 5' termini of the phi29 DNA.

J Virol, 1978 Dec, 28(3), 877 - 84
Bacteriophage lambda mutants (lambdatp) that overproduce repressor; Truitt CL et al.; Lambda tp mutants, selected for their ability to form turbid plaques on lon hosts, overproduce repressor . The tp1 and tp2 mutations have been located within (or adjacent to) the cIII gene . The tp1 mutation reduced late gene expression, as measured by endolysin synthesis (in the absence of functional cI repressor) and progeny phage yield . The tp4 mutation was mapped in the cY-cII region, and complementation tests indicated that tp4 affects the diffusible product of the cII gene . The tp4 mutation also reduced progeny production, but did not markedly affect endolysin synthesis.

J Virol, 1978 Dec, 28(3), 835 - 42
Transcription of bacteriophage M13 DNA: existence of promoters directly preceding genes III, VI, and I; Edens L et al.; In vitro transcription and coupled transcription-translation studies have been performed with restriction fragments of bacteriophage M13 replicative-form DNA which contain either gene III, gene VI, or gene I . It could be demonstrated that DNA fragments which contain gene III were able to direct the synthesis of gene III protein . Fragments which encompassed genes VI and I gave rise to the synthesis of gene I protein only, whereas gene I-containing fragments were able to direct the synthesis of gene I protein . None of the fragments studied gave rise to a detectable level of gene VI protein, although an RNA transcript of gene VI could readily be obtained during in vitro transcription of the relevant gene VI-containing DNA fragments . From these results we have concluded that the promoters A0.44 and A0.49 are located in front of genes VI and I, respectively, and that gene III is also equipped with a promoter (X0.25) . Introduction of a single cleavage within the gene III region does not abolish the expression of genes VI and I in vitro . Hence, the expression of these genes is not solely dependent on the initiation of RNA synthesis at the gene III promoter or on leakage of transcription through the central termination site (T0.25), but is also determined by the initiation frequency of RNA synthesis at their individual promoters.

Nucleic Acids Res, 1978 Dec, 5(12), 4725 - 36
Detection of yeast ribosomal RNA sequences in E . coli infected with hybrid bacteriophage; Kramer RA et al.; Yeast ribosomal DNA was inserted into Escherichia coli on a bacteriophage vector and the host cell RNA was then extracted and analyzed for the presence of yeast ribosomal RNA sequences . RNA complementary to yeast rDNA was detected by hybridization . The transcription of yeast rDNA was found to be independent of phage RNA synthesis and to occur on the same DNA strand as rRNA transcription in yeast . However, hybridization to restriction fragments of yeast rDNA suggested that the RNA species detected in E . coli differ somewhat from authentic yeast rRNA.

Nucleic Acids Res, 1978 Dec, 5(12), 4677 - 98
Nucleotide sequence of gene VII and of a hypothetical gene (IX) in bacteriophage M13; Hulsebos T et al.; A DNA fragment containing gene VII of bacteriophage M13 has been transcribed and the nucleotide sequence of this 169-nucleotides long transcript was determined by RNA sequencing methods . Additionally, the nucleotide sequence of this gene and parts of its neighbouring genes V and VIII has been determined by the dimethylsulphate-hydrazine technique . The reading frame of gene VII has been established by determining the nucleotide changes occurring in the transcripts of two amber mutants of this gene . From these combined data it is apparent that gene VII is only 99 nucleotides long and is immediately followed by the termination codon UGA . Its initiation codon AUG is separated from gene V by only a single nucleotide . It was noted that between the UGA termination codon of gene VII and the initiation codon of the next gene (gene VIII) there is space for another, hitherto unknown gene . This gene (IX) most probably codes for the small polypeptide ("C-protein") present in mature M13 phage particles.

Nucleic Acids Res, 1978 Dec, 5(12), 4479 - 94
Bacteriophage lambda and plasmid vectors, allowing fusion of cloned genes in each of the three translational phases; Charnay P et al.; We have constructed vectors from bacteriophage lambda and from plasmid pBR322 having a single EcoRI restriction site which is immediately downstream from the lac UV5 promotor . Each vector allows the fusion of a cloned gene to the lac Z gene in a different phase relative to the translation initiation codon of the lac Z gene . These vectors were constructed through modification of the initial EcoRI restriction site by S1 endonuclease treatment and then addition of octadeoxyribonucleotides (EcoRI linkers), which shifted the restriction site by 2 or 4 nucleotides . Used in combination these vectors should allow translation of a cloned gene in any one of the three coding phases . The bacteriophages vectors are certified as B2 (EK2) safety level vectors by the French "recombinaison genetique in vitro" committee (D.G.R.S.T.).

J Gen Virol, 1978 Dec, 41(3), 609 - 22
Formation of concatemeric DNA as an intermediate in the replication of bacteriophage T1 DNA molecules; Ritchie DA et al.; The structure of intracellular DNA extracted from phage T1 infected cells was analysed by sedimentation through sucrose gradients . DNA labelled with 3H-dThd during a short pulse given at any time during T1 DNA synthesis sedimented in neutral gradients as a broad heterogeneous band with a large fraction of the label sedimenting more rapidly than mature T1 DNA molecules . Rapidly-sedimenting label was also observed when pulse-labelled DNA was denatured and analysed on alkaline sucrose gradients . Electron microscopy of intracellular T1 DNA revealed linear molecules of variable length the longest of which were three to four times the mature genome length . The distribution of lengths derived from electron microscopy are consistent with the molecular length distributions calculated from the sedimentation coefficients . We conclude that the rapidly-sedimenting DNA is in the form of concatemers consisting of linear tandem repeats of the T1 genome . The concatemeric form of replicating T1 DNA is a precursor of progeny T1 genomes since in pulse-chase experiments it was converted efficiently into mature, infectious T1 phage particles . The identification of this concatemeric form of T1 DNA provides supporting evidence for the model proposed by Gill & MacHattie (1976) to account for the formation of the very limited number of cyclic permutations of gene sequence found for mature T1 DNA molecules.

J Gen Microbiol, 1978 Dec, 109(2), 329 - 33
Chromosomal location of the mop (groE) gene necessary for bacteriophage morphogenesis in escherichia coli; Guest JR et al.; The chromosomal location of a host gene, mop (groE), which is essential for the morphogenesis of several bacteriophages in Escherichia coli, was determined by two- and three-factor transductional crosses using phage P1 . Cotransduction frequencies beteen mop and other markers were: aspA, 90%; ampA, 77%; frdA, 73%; mel, 24% . The sequence of markers in the corresponding segment (mel to purA; 91.5 to 93.5 min) of the E . coli linkage map was shown to be mel--aspA--mop(groE)--ampA--frdA--pur A.

Proc Natl Acad Sci U S A, 1978 Dec, 75(12), 5827 - 30
Three-dimensional structure of thioredoxin induced by bacteriophage T4; Soderberg BO et al.; The three-dimensional structure of thioredoxin from bacteriophage T4 has been determined from a 2.8-angstrom resolution electron density map . Phase angles for this map were determined from one heavy atom derivative and anomalous differences from cadmium in the native crystals . The molecule of 87 amino acid residues is built up from two simple folding units; a betaalphabeta unit from the amino end of the chain and a betabetaalpha unit from the carboxyl end . This structure is similar to that of thioredoxin from Escherichia coli in spite of their completely different amino acid sequences . The redox-active S--S bridge is part of a protrusion of the molecule as in E . coli thioredoxin, but with quite different surroundings . The structural differences in this region have been correlated to differences in specificity towards the enzyme ribonucleotide reductase from different species.

J Virol, 1978 Dec, 28(3), 717 - 24
Replication of RNA bacteriophages in the presence of rifamycin; Bauman V et al.; Replication of RNA bacteriophages in the presence of rifamycin was studied in different Escherichia coli strains that vary in RNase content but are not isogenic: AB259 RNase+, Q13 RNase I- PNPase-, AB105 RNase I- RNase III- . It was found that rifamycin did not affect characteristics of phage replication such as the general pattern of viral RNA synthesis and intracellular development of the phage . These characteristics are strain specific and independent of the cell growth rate, which defines only phage release . The inhibition of cell division by rifamycin interfered with the release of the phage and thus produced an apparent effect of rifamycin on phage replication.

J Virol, 1978 Dec, 28(3), 679 - 85
Replication of bacteriophage M13 . XIV . Differential inhibition of the replication of M13 and M13 miniphage in a mutant of Escherichia coli defective in the 5' leads to 3' exonuclease associated with DNA polymerase I; Chen TC et al.; Previous studies have shown that M13 single-strand synthesis is inhibited at nonpermissive temperature in Escherichia coli polAexl, a temperature-sensitive mutant defective in the 5' leads to 3' exonuclease activity of polymerase I (T.-C . Chen and D . S . Ray, J . Mol . Biol . 106:589-604, 1976) . Under these conditions the formation of covalently closed replicative form (RF) molecules is greatly reduced, and miniature forms of RF accumulate . We show here that the accumulation of mini-RFs is the consequence of a differential inhibition of the replication of unit-length phage and preexisting miniphage rather than a de novo production of miniphage . Mini-RFs do not accumulate even after as many as nine cycles of growth in the mutant host infected only with unit-length phage . Mixed infections of the mutant host with plaque-purified unit-length phage and a single cloned miniphage show that discontinuities in the mini-RFs are joined with higher efficiency than are those contained in unit-length RFs . After a shift to nonpermissive temperature during single-strand synthesis in cells infected with plaque-purified phage alone, M13 RFs are found largely as RFII molecules (RF form having one or more single-strand discontinuities) containing only a single discontinuity in the viral strand . The inability of the accumulated unit-length RFII molecules to actively replicate may reflect the presence of either a bound protein or RNA primer on the 5' terminus of the viral strand and provides further support for the existence of distinct initiation and termination events in the synthesis of the viral strand.

J Gen Microbiol, 1978 Dec, 109(2), 329 - 33
Chromosomal location of the mop (groE) gene necessary for bacteriophage morphogenesis in Escherichia coli; Guest JR et al.; The chromosomal location of a host gene, mop (groE), which is essential for the morphogenesis of several bacteriophages in Escherichia coli, was determined by two- and three-factor transductional crosses using phage P1 . Cotransduction frequencies between mop and other markers were: aspA, 90%; ampA, 77%; frdA, 73%; mel, 24% . The sequence of markers in the corresponding segment (mel to pur A; 91.5 to 93.5 min) of the E . coli linkage map was shown to be mel-aspA-mop(groE)-ampA-frdA-purA.

Cell, 1978 Dec, 15(4), 1187 - 97
Nonsense and insertion mutants in the relA gene of E . coli: cloning relA; Friesen JD et al.; We have made use of lysogens of a specialized transducing bacteriophage, lambdapyrG+ relA+, to select nonsense (relAnon) and insertion (relAins) mutations in the relA gene . Three independent relAnon mutants were isolated on the phage . In all three, the relaxed phenotype was suppressed by supD, supE, supF or sup6 . Three independent relAins mutants were isolated, all containing an insertion element (probably IS2) in an apparently identical location in the relA gene . Polyacrylamide gel electrophoretic analysis of peptides synthesized by the phages in ultraviolet lightkilled host cells revealed that no stringent factor was coded for by either the relAins or relAnon phages (the latter in a sup+ cell); stringent factor was detected when the relAnon phages were used in a similar experiment with supD or supE host cells . The relAnon and relAins mutations could be crossed in haploid form in the E . coli chromosome . These recombinants grew with a normal doubling time, had a ppGpp pool which was between 70 and 100% compared with the classical relA strain, and underwent a normal carbon source shift-down . A restriction endonuclease map of the pyrG relA region of the specialized transducing phage is presented in which the position of the insertion element (recognized by a novel Hind III-cut site) defines the position of the relA gene . This position was verified by an analysis of the structure of five plasmids formed by cloning portions of the region in the pBR322 cloning vehicle . Our results indicate that the relA gene is not an essential cellular function, that there might be a second mechanism for the synthesis of basal level ppGpp in the cell and that the sole function of the relA gene is apparently the high level ppGpp synthesis triggered in response to deacylated tRNA.

Mutat Res, 1978 Dec, 52(3), 313 - 22
Non-essential UV-sensitive bacteriophage T4 mutants affecting early DNA synthesis: a third pathway of DNA repair; Minderhout L et al.; Non-essential bacteriophage T4 mutants uvs58 and uvs79 showed a lower UV sensitivity than either the excision-repair mutant v am5 or the replication-dependent recombination-repair mutant y10 . The UV sensitivity of double and triple mutants carrying one of the mutations uvs58 or uvs79, and v am 5 or (and) y10 was higher than the sum of the sensitivities of the single mutants . The uvs58 mutation was mapped to the early gene region, close to amN81 (gene 41) . The unirradiated mutants uvs58 and uvs79 accumulated newly synthesized DNA at a slower rate than wild-type T4 . Double mutants uvs58:am59 and uvs79:am59 showed DNA synthesis in E . coli B su- to be arrested at a 3--5 times lower level than that in am59-infected cells . Chloramphenicol, added 9--12 min after infection, suppressed arrests of DNA synthesis, the double mutants showing a lag of 8 min as compared with am59 . Results from analysis of sucrose gradients of parental uvs58 and uvs79 DNA were in agreement with the suggestion of a mutation in an early function . The mutants uvs58 and uvs79 are suggested to be defective in a component of the DNA replication apparatus with a function in the adaptation to irregularities in the DNA structure . The third pathway of UV repair is tentatively designated as non-catalytic replication repair.

J Bacteriol, 1978 Dec, 136(3), 1192 - 6
Construction of a hybrid bacteriophage-plasmid recombinant DNA vector; Donoghue DJ et al.; A phage-plasmid hybrid was constructed for use as a recombinant DNA vector, allowing the propagation of cloned EcoRI restriction endonuclease fragments of about 2 X 10(6) to 11 X 10(6) daltons . The colicin E1 plasmid replicon was fused to the left arm of a lambdagt generalized transducing phage with a thermolabile repressor, yielding a genome which could be replicated either by phage lambda functions or via the colicin E1 plasmid replicon . At the nonpermissive temperature, phage functions were derepressed and phage growth occurred lytically . Alternatively, at the permissive temperature, lambda functions were repressed and the vector replicated as a covalently closed circular plasmid . The phage-plasmid hybrid vector could be maintained at a copy number determined by the colicin E1 plasmid replicon and was also sensitive to amplification after chloramphenicol treatment . An EcoRI fragment of Escherichia coli DNA encoding genes of the arabinose operon also was inserted into the central portion of the vector.

J Bacteriol, 1978 Dec, 136(3), 1109 - 19
malB region in Escherichia coli K-12: specialized transducing bacteriophages and first restriction map; Marchal C et al.; By starting from an Escherichia coli K-12 strain with a lambda phage integrated in the malB region, series of transducing phages carrying part or all of the malB region have been isolated . Genetic mapping of the transduced malB fragments was accomplished by complementation and recombination with known mutations in the region . By using the DNA of these phages, it was found that the malB region is cleaved by the restriction enzymes BglII, EcoRI, HaeII, HincII, SalI, and SstI, but not BamHI, HindIII, KpnI, PstI, XbaI, or XhoI . A physical map was constructed and tentatively correlated with the genetic map.

J Bacteriol, 1978 Dec, 136(3), 1084 - 93
Properties of lambda transducing bacteriophages carrying R100 plasmid DNA: mercury resistance genes; Dempsey WB et al.; Three lambdamer (resistance to Hg2+ and mercurials) transducing phages were prepared from three independent cointegrate isolates of bacteriophage lambda and plasmid R100 . DNA heteroduplex and restriction nuclease analyses of the lambdamer DNA showed that all three phages had resulted from lambda insertion at kilobase coordinate 8.6 of plasmid R100, followed by loss of different lengths of lambda DNA and replacement with different lengths of R100 DNA . Two of the lambdamer phages were defective, containing deletions from lambdaatt through the lambdaN gene and into the lambdarex gene; the third, VAlambda14, was an N+ Spi- plaque-forming phage . With VAlambda14, N-dependent transcription of R100 mer from the lambdapL promoter suggested that transcription of mer proceeded in the direction from IS1b toward the sulfonamide resistance determinant (i.e., from a plasmid promoter in restriction nuclease fragment EcoRI-H toward fragment EcoRI-I) . Phage-directed protein synthesis in a UV-irradiated lambdaind- lysogen showed the Hg2+-inducible synthesis of three major polypeptides of molecular weights 68,000, 11,500, and 8,500 and three minor ones of molecular weights 54,000, 33,000, and 13,500 . The largest of the major polypeptides is identified as the subunit of the mercuric reductase enzyme . The functions of the smaller polypeptides are not known . Hg2+ reductase enzyme assays confirmed the regulation of mer synthesis during phage infection.

Proc Natl Acad Sci U S A, 1978 Dec, 75(12), 6182 - 6
A single base-pair change creates a Chi recombinational hotspot in bacteriophage lambda; Sprague KU et al.; X4+ mutations, responsible for the Chi phenotype in phage lambda, locally increase the rate of recombination promoted by the Escherichia coli recombination system (Rec) . X+ mutations in the cII gene, one of a few sites in lambda at which such mutations arise, were located genetically and physically with overlapping deletions . DNA sequence analysis of the deletion segment containing the X+ C mutations showed that two independent X+ C mutations arose by the same A-T to T-A transversion . Presumably, this change creates a nucleotide sequence recognized by a protein involved in a rate-limiting step of recombination.

Proc Natl Acad Sci U S A, 1978 Dec, 75(12), 6144 - 8
Marker rescue and partial replication of bacteriophage T7 DNA; Burck KB et al.; Experiments reported here show that some UV-irradiated wild-type T7 phage markers can be rescued efficiently by coinfection with T7 amber mutant phage in a permissive host . Other results show that the segments of a UV-irradiated genome that replicate efficiently are those that also are rescued efficiently during a marker rescue experiment . At higher doses, fewer markers are rescued efficiently and fewer segments of the genome replicate efficiently . The results clearly indicate that the probability of marker rescue is correlated with the ability of the DNA containing the marker to replicate . Sucrose density gradient analysis shows that UV irradiation does not produce double-strand scissions in T7 DNA at doses used here . Therefore, the partial replication and rescue of markers from the left end of the genome is not due simply to injection of only the left end of the T7 DNA.

Proc Natl Acad Sci U S A, 1978 Dec, 75(12), 5817 - 21
Interaction of bacteriophage lambda repressor with nonoperator DNA containing single-strand gaps; Sussman R et al.; In direct binding assays, purified lambdaind+ repressor displayed high affinity for nonoperator DNA containing single-strand gaps . Its affinity for this same DNA but completely double-stranded, nicked, or denatured was considerably lower . In contrast, purified lambdaind- repressor had 1/10th the affinity for the gapped DNA, a level comparable to that of purified lac repressor . In the presence of limiting amounts of ind+ repressor, nonoperator DNA containing gaps could be shown to compete effectively with lambda DNA for binding of repressor . A previous model of lambda induction {Sussman, R . & Ben-Zeev, H . (1975) Proc . Natl . Acad . Sci . USA 72, 1973--1976}, based on the assumption that this phenomenon involves the binding of repressor to lesions in the host DNA, is reevaluated in the light of the data reported here.

C R Acad Sci Hebd Seances Acad Sci D, 1978 Dec, 287(16), 1453 - 6
{Cloning of the hepatitis B virus genome in Escherichia coli}; Fritsch A et al.; The whole genome of the hepatitis B virus (Dane particles) was inserted in vitro in the genome of the bacteriophage lambda gtWES . LAMBDA B . The recombinant DNA molecule was cloned in E . coli . Amplification of the hybrid bacteriophage enables the preparation of large amounts of hepatitis B virus DNA . The possibilities offered by the utilization of this recombinant bacteriophage are discussed.

Mol Gen Genet, 1978 Nov 29, 167(2), 197 - 207
Recombinational repair of alkylation lesions in phage T4 . II . Ethyl methanesulfonate; Johns V et al.; Treatment of bacteriophage T4 by ethyl methanesulfonate (EMS) caused more than a doubling in recombination between two rII markers . The functions of genes 47, 46, 32, 30, uvsX and y are known to be required for genetic recombination, and mutants defective in these genes were found to be more sensitive to inactivation by EMS than wild-type phage . This suggests that a recombinational pathway involving the products of these genes may be employed in repairing EMS induced lethal lesions . Genes 45 and denV are apparently not involved in recombination, and mutants defective in these genes were not EMS-sensitive . Gene 47, 46 and y mutants which were defective in the repair of EMS induced lethal lesions had no detectable deficiency in their ability to undergo EMS-induced mutation . This implies that recombinational repair of EMS lesions does not contribute substantially to EMS mutagenesis . The results obtained here with EMS are general similar to the results reported in the preceding paper with MNNG, suggesting that the lesions caused by both of these monofunctional alkylating agents may be eliminated by similar recombinational repair processes.

Biochim Biophys Acta, 1978 Nov 21, 521(1), 27 - 44
Expression of bacteriophage M13 dna in vivo . I . Synthesis of phage-specific RNA and protein in minicells; Smits MA et al.; It is demonstrated that after infection of the appropriate minicell-producing strain of Escherichia coli with the filamentous bacteriophage M13, its replicative form DNA is segregated into minicells . Consequently these minicells have acquired the capability to direct the synthesis of phage-specific RNA and protein . Comparision of the electrophoretic mobilities of phage-specific RNA species made in vitro with those made in M13 replicative form DNA harbouring minicells, have indicated that almost all in vitro synthesized G-start RNAs have an equivalent among the in vivo synthesized RNA products . Furthermore it could be demonstrated that in M13 replicative form DNA harbouring minicells the phage-specific proteins encoded by genes III, IV, V and VIII are made . In addition the synthesis of a phage-specific polypeptide (molecular weight approx . 3000) co-migrating with the recently discovered capsid protein (designated C-protein) could be demonstrated . The meaning of these results for the resolution of the regulatory mechanisms operative during the life cycle of this phage will be discussed.

Mol Gen Genet, 1978 Nov 16, 167(1), 105 - 12
Evidence for a near UV-induced photoproduct of 5-hydroxymethylcytosine in bacteriophage T4 that can be recognized by endonuclease V; Childs JD et al.; Non-photoreactivable endonuclease V-sensitive sites have been detected in the DNA of wild type bacteriophage T4 irradiated with near UV light (320 nm) . Such sites were not detected in the DNA of (a) wild type T4 irradiated with far UV (254 nm) or (B) in T4 mutants in which non-glucosylated 5-hydroxy-methylcytosine (5HMC) or cytosine replaces glucosylated 5HMC normally present in T4, irradiated with 320 nm or 254 nm light . Although the non-photoreactivable sites accounted for approximately 50% of the endonuclease V-sensitive sites in the DNA of glucosylated T4 irradiated with near UV, there was very little difference in the sensitivities of T4 containing glucosylated 5HMC, non-glucosylated 5HMC and cytosine to near UV (313 nm) . We propose that the photoproduct responsible for the non-photoreactivable, but endonuclease V-sensitive, sites in glucosylated DNA is formed from glucosylated 5HMC and that a similar photoproduct is formed from non-glucosylated 5HMC or cytosine in the appropriate phage strains . We further propose that the glucosylated 5HMC photoproduct is non-photoreactivable whereas the cytosine and non-glucosylated 5HMC photoproducts are photoreactivable and are therefore possibly cyclobutane dimers.

Nature, 1978 Nov 16, 276(5685), 236 - 47
Nucleotide sequence of bacteriophage G4 DNA; Godson GN et al.; 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 similarity between the untranslated intergenic regions of G4 and phiX174, but despite this the sequences of the J/F, F/G and H/A untranslated spaces in both genomes have similar sized hairpin loops, which may be related to their function.

Eur J Biochem, 1978 Nov 15, 91(2), 465 - 73
The effects of tiamulin, a semisynthetic pleuromutilin derivative, on bacterial polypeptide chain initiation; Dornhelm P et al.; Tiamulin, a water-soluble and highly effective semisynthetic derivative of pleuromutilin leads to the formation of physiologically inactive polypeptide chain initiation complexes which readily decompose and do not enter the phase of peptide chain elongation . Once elongation has begun it continues even in the presence of tiamulin as has been shown by measuring the formation of N-acetylphenylalanine-poly(phenylalanine) . The formation of abortive initiation complexes was observed regardless of whether AcPhe-tRNA of fMet-tRNA was used as an initiator or whether artificial messengers or a natural messenger, like R17 bacteriophage RNA, was used . When this drug was acting on whole cells, it led to the disappearance of polysomes . The only structures which could be detected were of the monosome size . Therefore, polysomes seem to elongate the polypeptide chains in whole cells in the presence of this antibiotic, but since effective reinitiation is blocked, the polysome pool of the cell soon becomes depleted.

Mol Gen Genet, 1978 Nov 9, 166(3), 277 - 85
Specific labelling of replicating SPP1 DNA: analysis of viral DNA synthesis and identification of phage DNA-genes; Burger KJ et al.; Specific labelling of replicating bacteriophage SPP1 DNA can be achieved by infection at nonpermissive temperature of a B . subtilis strain carrying the initation mutation dnaB ts134 . Under these conditions host DNA synthesis is reduced by 90 to 95% . This technique was used to identify cistrons of SPP1 involved in phage DNA synthesis and to define intermediates in SPP1 replication.

Mol Biol (Mosk), 1978 Nov-Dec, 12(6), 1329 - 40
{Structural organization of the genome of bacteriophage T5 by specific endonucleases}; Chernov AP et al.; The DNA of Bacteriophage T5+ has been treated with restriction endonucleases EcoRI, HindIII, BamI, SmaI, PstI, SalI, KpnI and the electrophorectic pattern obtained in agarose gel has been analyzed in order to localize the specific cleavage sites on the T5 DNA . The localization of cleavage sites has been resolved from the electrophoretic pattern of double and partial digests, the digests of isolated restriction fragments and the digests of deletion mutant T5 st(O) DNA . Four BamI cleavage sites have been found and localized on the physical map of T5 DNA at 0.225; 0.68; 0.715 and 0.725 fractional lenght . Endonuclease PstI cuts T5 DNA at 11 sites: 0.095; 0.215; 0.320; 0.510; 0.635; 0.675; 0.710; 0.770; 0.810; 0.840; 0.875 fractional length . Six KpnI cleavage sites have been mapped at 0.140; 0.160; 0.530; 0.720; 0.760; 0.840 fractional length . 14 out of 17 HindIII cleavage sites have been localized at 0.10; 0.24; 0.255; 0.345; 0.40; 0.52; 0.54; 0.57; 0.70; 0.76; 0.80; 0.84; 0.87; 0.89, fractional length of T5 DNA . Complete cleavage map of the phage genome is presented for seven restriction enzymes.

Cell, 1978 Nov, 15(3), 1045 - 53
Nucleotide sequence of the J gene and surrounding untranslated regions of phage G4 DNA: comparison with phage phiX174; Fiddes JC et al.; 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 by 32 untranslated nucleotides; the deletion of one third of the gene J coding region, so that the G4 protein is only 24 amino acids long compared with 37 amino acids in phiX174; and the establishment of a long untranslated region between G4 genes J and F, which despite many nucleotide changes retains the ability to form a stable hairpin loop in the same place and with the same geometry as in phiX174 . The G4 overlapping gene E is longer than in phiX174 and extends beyond gene D . Sixteen nucleotides at the end of genes D and E in phiX174 are duplicated in G4 before gene J.

In Vitro, 1978 Nov, 14(11), 935 - 8
Decontamination of bacterial infection of monolayer cultures with a specific bacteriophage; Riche PH et al.; A few cell lines and primary monolayer cultures were accidentally infected by bacteria . These cultures were successfully decontaminated by means of the specific bacteriophage virus after quick identification of the responsible bacteria . This method presents a practical interest for preservation of valuable cultures.

Proc Natl Acad Sci U S A, 1978 Nov, 75(11), 5594 - 8
Analysis of bacteriophage P1 immunity by using lambda-P1 recombinants constructed in vitro; Sternberg N et al.; We describe the dissection and reconstruction of a complex control circuit, the P1 immunity system, by a method that involves inserting EcoRI-generated fragments of P1 DNA into lambda vectors that can then be sequentially inserted into a bacterial cell . Using these techniques we have isolated lambda-P1 hybrid phages that express the products of P1 genes c1, c4, ant, and ban and, in appropriately constructed lysogens, confirmed the roles played by the first three of these products in phage immunity . In addition we have localized to particular P1 fragments the sites requisite for expression and repression of these gene products . The analysis leads to the conclusion that gpant acts in trans to antagonize repression mediated by gpc1, in support of one of two proposed models for gpant action . Moreover, two features of the immunity system are revealed: (i) a hitherto unknown component that effects gpc1 repression; and (ii) an unexpected ability of gpc4 to channel a superinfecting c1+ phage into the lysogenic state, which suggests that gpc4 activity regulates the establishment phase of lysogeny.

Proc Natl Acad Sci U S A, 1978 Nov, 75(11), 5437 - 41
Structure of the lambda att sites generated by int-dependent deletions; Hoess RH et al.; Bacteriophage lambda integrates into the chromosome of its Escherichia coli host by means of a site-specific recombination between a locus on the phage chromosome (phage att site) and a locus on the bacterial chromosome (bacterial att site) . The nucleotide sequence of four lambda att sites altered in site-specific recombination has been determined . The int-dependent deletions that generated these att sites have one end point within the phage att site and extend either to the left or to the right . As a result of the new internucleotide bond created by deletion formation, these phage have alterations in the 15-base-pair common core region . The new DNA sequences brought to the att sites by the deletions, designated delta for regions to the left and delta' for regions to the right, do not share any discernible homology with their analogous counterparts in the phage att site arms, P and P', respectively, or with the bacterial att site arms, B and B', respectively . The finding of alterations in the 15-base-pair common core region necessitates a reinterpretation of the genetic properties of these att sites in site-specific recombination . The structure of these sites in relation to their genetic properties can be viewed as being consistent with a model in which the only specificity elements in int-dependent site-specific recombination are the common core region, O, and the phage arms, P and P'.

Proc Natl Acad Sci U S A, 1978 Nov, 75(11), 5281 - 5
A photo-CIDNP study of the interaction of oligonucleotides with gene-5 protein of bacteriophage M13; Garssen GJ et al.; It is shown that photo-CIDNP effects (CIDNP, chemically induced dynamic nuclear polarization) can be generated in the 360-MHz proton NMR spectrum of gene-5 protein from bacteriophage M13 . This technique is used to determine the number of tyrosyl residues at the surface of the protein and to assign the resonances from the 3,5-ring protons of these residues . The DNA-binding site of the protein is investigated by formation of complexes with oligonucleotides . Complex formation leads to shifting and/or quenching of the photo-CIDNP emission signals of the surface tyrosines, implying that they are involved in DNA-protein interaction . These experiments are complemented by studying the complex formation of Lys-Tyr-Lys to poly(A).

Nucleic Acids Res, 1978 Nov, 5(11), 4129 - 39
An Escherichia coli ribonuclease which removes an extra nucleotide from a biosynthetic intermediate of bacteriophage T4 proline transfer RNA; Schmidt FJ et al.; The biosynthesis of bacteriophage T4 tRNAPro, tRNASer, and tRNAIle requires enzymatic removal of extra nucleotides from the 3' terminus of the respective precursor RNAs . A ribonuclease activity capable of catalyzing such reactions has been partially purified from uninfected Escherichia coli using an artificial precursor RNA as substrate . A number of ribonuclease activities were resolved during purification . Use of E . coli strain BN, a mutant known to be deficient in the relevant ribonuclease activity, permitted us to identify it in wild-type cells . This activity was designated the BN ribonuclease . BN ribonuclease had an apparent molecular weight of 35,000 as measured by Sephadex gel filtration . Mg2+ was required for activity, which was optimal at {Mg2+} of 2mM . Activity did not require monovalent cations K+ or Na+ . BN ribonuclease was less efficient at removing extra residues in the biosynthesis of tRNASer and tRNAIle than in the biosynthesis of tRNAPro.

J Virol, 1978 Nov, 28(2), 643 - 55
Model for DNA packaging into bacteriophage T4 heads; Black LW et al.; The mechanism of DNA packaging into bacteriophage T4 heads in vivo was investigated by glucosylation of hydroxymethylcytosine residues in a conditionally glucose-deficient host . Cytoplasmic DNA associated with partially packaged ts49 heads can be fully glucosylated, whereas DNA already packaged into these heads is shown to be resistant to glucosylation . After temperature shift and completion of arrested packaging into the reversible temperature-sensitive ts49 head, the structure of the DNA in the mature ts49 phage was investigated by restriction enzyme digestion, autoradiography, and other techniques . Such mature DNA appears to be fully glucosylated along part of its length and nonglucosylated on the remainder . Its structure suggests that the DNA is run into the head linearly and unidirectionally from one mature end and that there is little sequence specificity in that portion of the T4 DNA which first enters the capsid . This technique should be useful in investigation of the three-dimensional structure of first- and last-packaged DNA within the head; preliminary studies including autoradiography of osmotically shocked phage suggest that the DNA which first enters the head is deposited toward the center of the capsid and that the end of the DNA which first enters the head exits first upon injection . In conjunction with studies of the structure of condensed DNA, the positions and functions of T4 capsid proteins in DNA packaging, and the order of T4 packaging functions {Earnshaw and Harrison, Nature (London) 268:598-602, 1977; Hsiao and Black, Proc . Natl . Acad . Sci . U.S.A . 74:3652-3656, 1977; Muller-Salamin et al., J . Virol . 24:121-134, 1977; Richards et al., J . Mol . Biol . 78:255-259, 1973}, the features described above suggest the following model: the first DNA end is fixed to the proximal apex of the head at p20 and the DNA is then pumped into the head enzymatically by proteins (p20 + p17) which induce torsion in the DNA molecule.

Genetika, 1978 Nov, 14(11), 1908 - 12
{Adsorptive capacity of bacteriophage Mu on Escherichia coli K-12 strains with deletions in the attlambda region}; Koretskaia NG et al.; Escherichia coli strains with deletions in att lambda region were obtained . The comparison of the extent of deletions with the sensitivity of the corresponding mutant clones to phage Mu showed that the gene controlling the sensitivity of E . coli K-12 to the phage Mu is located in nad A-gal region of the bacterial chromosome . It is shown that the resistance of E . coli strains which had lost the region of bacterial chromosome between nad A gene and genes of gal-operon have adsorption character . Deletion of the nad A-gal region does not affect the adsorption of other phages (lambda, P1 and T4) . Thus, the gene, located in this region, is responsible for the specific adsorption of the phage Mu.

J Bacteriol, 1978 Nov, 136(2), 808 - 11
Plasmids of incompatibility group P code for the capacity to propagate bacteriophage IKe; Grant RB et al.; Seven of eight plasmids of incompatibility group P were found to code for the capacity to propagate bacteriophage IKe in Escherichia coli . Six of the seven plasmids allowed propagation of IKe by one bacterial host (RG172) but not by another (RG176); the other plasmid allowed IKe propagation by both hosts . IKe propagation by a number of E . coli K-12 strains was quite variable . IKeh, an extended host range mutant of IKe, was found to plaque specifically on N+ and P+ strains.

J Bacteriol, 1978 Nov, 136(2), 742 - 56
Analysis of sequences transposed by complementation of two classes of transposition-deficient mutants of Tn3; Gill R et al.; The Tn1 and Tn3 elements are closely related transposons which carry the structural gene for ampicillin resistance . Two classes of deletion mutants of the plasmid pMB8::Tn3 (RSF1050) are unable to transpose ampicillin resistance but can be complemented in trans by a coresident Tn1 or Tn3 element . The analysis of the sequences transposed upon complementation of one class of mutants (type I) showed that the mutant element had undergone bona fide transposition . Complementation of the type II mutants led to the transposition of a sequence analogous to bacteriophage mu-promoted integration of non-mu DNA . The transposed sequence consisted of two Tn3 elements which flanked a single copy of the pMB8 portion of the RSF1050 genome . Complementation data indicated that the type II mutants are defective in at least one trans-acting function which must be supplied for transposition to occur . The nature of sequence transposed from the type II mutant is the consequence of a defective cis-acting function (or site) . In addition, the type II mutants were defective in a trans-acting function which regulated the frequency of transposition.

J Bacteriol, 1978 Nov, 136(2), 693 - 9
Role of lipopolysaccharide and outer membrane protein of Escherichia coli K-12 in the receptor activity for bacteriophage T4; Mutoh N et al.; Lipopolysaccharide isolated from Escherichia coli K-12 did not inactivate phage T4, although the cell envelopes with 1% sodium deoxycholate resulted in the release of cytoplasmic membrane proteins, 70% of the lipopolysaccharide, and almost all of the phospholipid . The reconstitution of phage receptor activity was achieved from deoxycholate-soluble and -insoluble fractions by dialysis against a solution of magnesium chloride . Lipopolysaccharide was the only essential component in the deoxycholate-soluble fraction . PhageT4-resistant mutants YA21-6 and YA21-82, having defects in the deoxycholate-soluble and -insoluble fractions, respectively, were isolated . The deoxycholate-soluble fraction of YA21-6 possessed heptoseless lipopolysaccharide, and this defect was responsible for the phage resistance . The deoxycholate-insoluble fraction of YA21-82 lacked outer membrane protein O-8 . The addition of O-8 to this fraction together with the wild-type lipopolysaccharide resulted in the appearance of the receptor activity . Furthermore, the reconstitution was successfully achieved with only O-8 and the wild-type lipopolysaccharide, indicating that O-8 was an essential component in the deoxycholate-insoluble fraction.

Mol Gen Genet, 1978 Oct 30, 166(2), 229 - 31
Binding of lac repressor to the secondary lac operator in Escherichia coli; Rambach A et al.; In the lac operon, the existence of a secondary repressor binding site, inside Z gene, had been inferred from in vitro binding studies (Reznikoff et al., 1974; Gilbert et al., 1975) . A series of deletions have been constructed from a lac transducing lambda bacteriophage . Some of those deleted bacteriophages have still the property of derepressing a chromosomal lac operon, even though they do not contain any more the lac operator . This phenomenon is an indication that the secondary repressor binding site is also active in vivo.

Mol Gen Genet, 1978 Oct 25, 166(1), 61 - 73
Mutational analysis of the operators of bacteriophage lambda; Flashman SM; Oc mutations in the operators of bacteriophage lambda have been used to analyze the functional organization of the operators . In each operator, repressor binding sites 1 and 2, as identified biochemically, were found to be primarily responsible for the repressor affinity of the operators in vitro and for the repression of lytic functions in vivo . In addition, both sites were shown to be involved in the action of cro product at the operators . The data obtained have been used to estimate the repressor affinities of the individual binding sites . These affinities suggest that repressor bound at OR1 and OR2 interacts cooperatively . The results obtained support a model for repression of the early lambda operons where repressor bound at binding sites 1 and 2 interferes with RNA polymerase binding to the promotor sites.

J Biol Chem, 1978 Oct 25, 253(20), 7149 - 57
The bacteriophage lambda int gene product . A filter assay for genetic recombination, purification of int, and specific binding to DNA; Kikuchi Y et al.; Bacteriophage lambda int gene is required for the integration of viral DNA into the chromosome of Escherichia coli . We have extensively purified the product of the int gene (Int) from a lysogen of E . coli that constitutively expresses this gene . Int was assayed by its ability to promote integrative recombination of supertwisted substrate DNA in vitro using a new method based on filter trapping of a recombinant product DNA . In order to catalyze integrative recombination, Int must be supplemented by other factors that can be extracted from bacterial host cells . By itself, purified Int does not demonstrate detectable endonuclease, exonuclease, or nicking-closing activities . However, Int does make stable complexes with double-stranded lambda-DNA containing an attachment site, the region at which recombination takes place . No stable complexes are observed between Int and lambda-DNA without an attachment site or between Int and DNA containing the bacterial site of integration . Int, therefore, appears to be a specificity element that relies on additional factor(s) to provide or activate the catalytic functions required for recombination.

Biochim Biophys Acta, 1978 Oct 24, 520(3), 505 - 11
Replication of bacteriophage G13 DNA in dna mutants of Escherichia coli; Taketo A et al.; Host functions required for replication of microvirid phage G13 DNA were investigated in vivo, using thermosensitive dna mutants of Escherichia coli . In dna+ bacteria, conversion of viral single-stranded DNA into double-stranded replicative form (stage I synthesis) was resistant to 150 microgram/ml of chloramphenicol or 200 microgram/ml of rifampicin . Although multiplication of G13 phage was severely inhibited at 42--43 degrees C even in dna+ host, considerable amount of parental replicative form was synthesized at 43 degrees C in dna+, dnaA or dnaE bacteria . In dnaB and dnaG mutants, however, synthesis of parental replicative form was severely inhibited at the restrictive temperature . Interestingly enough, stage I replication of G13 DNA was, unlike that of phiX174, dependent on host dnaC(D) function . Moreover, the stage I synthesis of G13 DNA in dnaZ was thermosensitive in nutrient broth but not in Tris/casamino acids/glucose medium . In contrast with the stage I replication, synthesis of G13 progeny replicative form was remarkably thermosensitive even in dna+ or dnA cells.

J Biol Chem, 1978 Oct 10, 253(19), 7011 - 6
Inhibition of primase, the dnaG protein of Escherichia coli by 2'-deoxy-2'-azidocytidine triphosphate; Reichard P et al.; 2'-Deoxy-2'-azidocytidine-5'-triphosphate was investigated as an inhibitor in two reconstructed enzyme systems which catalyze the replication of two viral DNAs . During replication of the duplex replicative form of phiX174 DNA, DNA polymerase III holoenzyme was weakly inhibited and inhibition was reversed by dCTP . A more pronounced inhibition, not reversed by either dCTP or CTP, was observed during replication of the single-stranded DNA of the bacteriophage G4, a close relative of phiX174 . This effect depended on the incorporation of 2'-deoxy-2'-azidocytidine-5'-triphosphate by primase (dnaG protein) which synthesizes a 29-residue RNA primer at the unique origin of bacteriophage G4 DNA replication . Extension of the primer strand, terminated by 2'-deoxy-2'-azidocytidine-5'-triphosphate is then severely inhibited . Primase was also inhibited by the 2'-deoxy-2'-azido derivatives of ATP, GTP, and UTP.

Nature, 1978 Oct 5, 275(5679), 424 - 8
Bacteriophages inhibit degradation of abnormal proteins in E . coli; Simon LD et al.; On infection of Escherichia coli cells by bacteriophages T4, T5 or T7, the degradation of E . coli protein fragments and abnormal proteins is inhibited . Normal E . coli proteins, however, continue to be degraded at their usual rates . T4 early proteins (s) is needed to inhibit the turnover of abnormal proteins in T4-infected E . coli cells.

J Biochem (Tokyo), 1978 Oct, 84(4), 917 - 24
"Thermal stability" maps for several double-stranded DNA fragments of known sequence; Ueno S et al.; The origin of cooperatively melting regions in DNA, which appear as fine structures in the optical melting profile, has been examined for DNA fragments of known base sequences from bacteriophages phiX174 and fd . Thermal stability maps, which indicate the states of base pairs along these DNA strands, were constructed within the established theoretical framework using the parameters which best reproduce the melting profiles obtained by high temperature resolution experiments . By comparing these stability maps with genetic maps, it was found that several cooperatively melting regions which span several hundred bases have some correlation with the gene locations.

J Virol, 1978 Oct, 28(1), 408 - 10
Identification of lysis protein E of bacteriophage phiX174; Pollock TJ et al.; 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 which gene E is wholly contained.

J Virol, 1978 Oct, 28(1), 270 - 8
Anomalous behavior of bacteriophage lambda polypeptides in polyacrylamide gels: resolution, identification, and control of the lambda rex gene product; Belfort M; The resolution of lambia proteins was compared on the two types of sodium dodecyl sulfate-polyacrylamide gels commonly in use . The two kinds of gel differ essentially in the ratio of the cross-linker, N'-N-bismethylene-acrylamide (bisacrylamide), to acrylamide monomer . Several lambda proteins migrate relatively more slowly in gels with high bisacrylamide/acrylamide ratios (HB gels) than in gels with low ratios, although the two types of gel are of roughly equivalent porosity . This effect is illustrated by a change in relative position of both the Rex and Int proteins, with apparent increases in molecular weight of about 8 and 15%, respectively, in the HB gels . This work confirms that like repressor and Int, the 28.5-kilodalton protein, identified as Rex on HB gels, is postively regulated by the lambdacII and cIII products and negatively controlled Cro . An intact y site is required for Rex and repressor expression after infection, whereas their synthesis in a lysogen is dependent upon a functional maintenance promoter, Prm.

Ann Microbiol (Paris), 1978 Oct, 129 B(3), 391 - 5
A model for plasmid maintenance of bacteriophage P1; Jaffe-Brachet A; Studies of the stability of P1 plasmid in a P1 cry Escherichia coli lysogen have suggested a model for equipartition of plasmid copies . Equipartition might be controlled by the detachment of P1 copies after replication, followed by their reattachment to membrane sites, in coordination with bacterial division.

Proc Natl Acad Sci U S A, 1978 Oct, 75(10), 5099 - 103
Bacteriophage lambda carrying the Escherichia coli chromosomal region of the replication origin; Miki T et al.; A transducing phage lambdaasn was isolated . The late gene region of its genome was found to have been substituted by an Escherichia coli chromosomal segment containing the genes bgIR, bgIC, glmS, uncA, and asn . Restriction endonuclease cleavage mapping and electron microscopic analysis of the lambdaasn DNA revealed that the size of the bacterial segment is approximately 1.75 X 10(7) daltons, corresponding to about 26.4 kilobases . The circular DNA of lambdaasn was digested with restriction endonuclease EcoRI, diluted, and sealed with DNA ligase . When the reaction mixture was used to transform a recipient E . coli strain, a small plasmid of about 1 X 10(7) daltons (named pMCR115) was obtained . Restriction endonuclease cleavage mapping of pMCR115 and other evidence suggested that it contained the replication origin (oriC) of the E . coli chromosome.

Gene, 1978 Oct, 4(2), 85 - 107
Plasmids useable as gene-cloning vectors in an in vitro packaging by coliphage lambda: "cosmids"; Collins J et al.; A plasmid which contains a cos site of lambda and can be packaged into lambda bacteriophage particles is termed a "cosmid" . Such plasmids can be used as gene cloning vectors in conjunction with an in vitro packaging system . The properties of a new series of cosmids based on the ColE1 replicon are described, including small temperature-sensitive plasmids which have lost mobilisation functions and carry no IS sequences . Amongst these plasmids are vectors for XmaI, BglII, BamHI, HindIII, PstI, KpnI, SalI and EcoRI . It is demonstrated that by using cosmids in particular size ranges these plasmids provide a high efficiency cloning system which yields essentially only hybrid clones without resort to a second selection or screening step, and without prior modification (e.g . phosphatase) treatment of the DNA . Attempts were made to optimise the cloning properties of the cosmid system . An Escherichia coli "gene bank" was obtained with an efficiency of 5 . 10(5) clones per microgram of E . coli DNA, and in which any particular unselected marker may be found in about one out of every 400 clones . It was demonstrated that deletion of mobilisation functions leads to loss of ability to form relaxation-complex without affecting copy number or segregation properties of the temperature-sensitive derivatives . The vectors are amplifiable in chloramphenicol to make up about 50% of the total cellular DNA.

Genetika, 1978 Oct, 14(10), 1706 - 13
{Effect of mutations in Escherichia coli genes PolAm RecA, RecB and RecC on the frequency of genetic recombination in amber-mutants involving the early genes of bacteriophage T4}; Slutskii AM et al.; Effects of mutations in genes PolA, RecA, RecB and RecC of Escherichia coli on the recombination frequencies between rII markers of T4 have been studied in conditions of partial inhibition of some early functions . It was found that the presence of the mutations in genes PolA or RecA decreased significantly the recombination frequency of phage amber mutant in the gene 43 (DNA polymerase), increased it in the case of amber mutation in the gene 46 (exonuclease) and had no effect on the recombination of amber mutants in genes 30, 32, 33, 41, 42, 45, 44, 52 . None of the amber mutants studied changed recombination frequencies in the presence of the mutations in genes RecB or RecC . Possible mechanisms of some of the effects observed are discussed.

J Bacteriol, 1978 Oct, 136(1), 423 - 8
Bacteriophage Mu-induced modification of DNA is dependent upon a host function; Khatoon H et al.; The DNA of bacteriophage Mu, extracted from induced lysates, is partially resistant to digestion by the endonuclease BalI . This modification of DNA is controlled by the Mu modification function (mom), which acts in conjunction with the dam (DNA-adenine methylation) function of Escherichia coli . Since the BalI recognition site is apparently different from the dam recognition site, these results imply that either the specificity of the dam function is changed by the mom function or the mom function requires the dam function for its activity.

Proc Natl Acad Sci U S A, 1978 Oct, 75(10), 4779 - 83
Symmetry mismatch and DNA packaging in large bacteriophages; Hendrix RW; A model is presented for the mechanism of packaging double-stranded DNA into phage heads . The model is based on, and rationalizes, the mismatch in symmetry between the heads and tails of large bacteriophages . DNA movement is postulated to be mediated by a rotating protein structure at the tail-proximal vertex of the head.

J Virol, 1978 Oct, 28(1), 262 - 9
Synthesis of T4 DNA and bacteriophage in the absence of dCMP hydroxymethylase; Morton D et al.; Several lines of research have suggested that the dCMP hydroxymethylase (HMase) coded by bacteriophage T4 is an essential protein in a DNA replication complex, as well as a supplier of hydroxymethyl dCMP for phage DNA synthesis . We show that a mutant {HMase, dCTPase, endonuclease II, endonuclease IV} which lacked this enzyme made cytosine-containing DNA at about two-thirds of the normal rate . When coupled with an alc mutation which permitted synthesis of late proteins, a small burst of phage was produced whose DNA contained no hydroxymethylcytosine . This pentuple mutant made both early and late proteins with abnormal kinetics, whereas the HMase+ parent showed normal kinetics . However, intracellular phage DNA showed no gross abnormalities in alkaline sucrose gradients . We conclude that HMase is not required for DNA synthesis when hydroxymethyl dCMP is not needed as a substrate; however, its absence still impairs both replication and transcription.

J Virol, 1978 Oct, 28(1), 95 - 105
Restriction fragment analysis of bacteriophage SPP1 in vitro transcription by host RNA polymerase; Chenciner N et al.; In vitro transcription of SPP1 DNA occurred on only one of the two strands, the same which is predominantly transcribed in SPP1-infected cells . Transcripts were distributed in several size classes . Analysis of elongation kinetics and of size distribution, coupled with hybridization to DNA restriction fragments, showed that some regions of the template have more initiation sites than others; some have none . Some regions were transcribed directly, some were transcribed from initiation sites located in other regions, and one was never transcribed . Several transcription initiation sites on SPP1 DNA are located on EcoRI fragment 1; four to five others are distributed among other fragments . Cutting the DNA with EcoRI did not introduce artifactual initiation sites . In vitro transcription units can be localized and oriented with respect to the EcoRI restriction map of SPP1 DNA.

J Biol Chem, 1978 Sep 25, 253(18), 6551 - 60
Mutagenesis at a specific position in a DNA sequence; Hutchison CA 3rd et al.; 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, by the combined action of subtilisin-treated Escherichia coli DNA polymerase I and T4 DNA ligase . Incomplete duplexes were removed or were inactivated by nuclease S1 and the products were used to transfect spheroplasts of E . coli . Both oligonucleotides induced specific mutations at high efficiency when used with heterologous template (15% mutants among progeny phage) . The am phages isolated by this procedure are phenotypically gene E mutants, and contain A at position 587 of the viral strand . They thus appear identical with am3 and provide evidence that the change G leads to A at position 587 is sufficient to produce a defective E function . Since the template for the induction of am mutants carried another genetic marker (sB1), the strains carrying the induced mutations have the new genotype am3 sB1 . It should be possible to introduce the am3 mutation into any known mutant strain of phi174 using this same oligonucleotide . Both possible transition mutations were induced in these experiments . In principle, the method could also induce transversions, insertions, and deletions . The method should be applicable to other circular DNAs of similar size, for example recombinant DNA plasmids.

J Biol Chem, 1978 Sep 25, 253(18), 6544 - 50
Localization of the arginine tRNA gene to the D segment of T5 bacteriophage DNA . A new procedure for producing duplex DNA fragments; Desai SM et al.; The tRNA genes of bacteriophage T5 are located in four clusters on the continuous heavy DNA strand (Chen, M.-J., Locker, J., and Weiss, S.B . (1976) J . Biol . Chem . 251, 536--547) . Three of the four clusters are within the DNA C segment; the fourth cluster, to which only tRNAArg has been localized, maps in a 3.02 kilobase (kb) region of which 1.99 kb are at the right end of the C segment and 1.03 kb at the left end of the D segment . In order to localize the tRNAArg gene further and to define its relationship to the C-D nick, we devised a suitable method for preparing T5 DNA fragments whose ends correspond to the position of the T5 DNA nicks contained in the light DNA strand . In this method, DNA is denatured, partially renatured, and digested with low concentrations of S1 nuclease . Agarose-gel electrophoresis of these digests gives a pattern of bands which correlate in size with the pattern expected from the nicked structure of T5 DNA . Annealing of individual purified T5 {35P}tRNA species to the T5 DNA fragments transferred to nitrocellulose filters shows that tRNAArg hybridizes exclusively to the D fragment and is therefore localized to 1.03 kb at the 5' (left) end of the heavy strand of the D segment . This finding suggests that the promotor for this early gene is to the right of the C-D nick in T5 DNA; hence, the C-D nick does not coincide with this early promotor.

Mol Gen Genet, 1978 Sep 20, 165(1), 39 - 46
Regulation of the int gene of bacteriophage lambda: activation by the cII and cIII gene products and the role of the Pi and Pl promoters; Oppenheim A et al.; The activation of the int gene by the cII and cIII gene products was studied by analysing int expression following infection of UV-irradiated cells by various phage mutants . Residual expression of int, probably from Pl, takes place in the absence of cII/cIII activation . Activation of the int gene, like that of the cI repressor gene, is poor at low multiplicities of infection . The mutation intC, which allows constitutive int expression in the lysogenic state, partially relieves the requirement for cII and cIII activation . The kinetics of Int synthesis after addition of the inhibitor rifampicin suggest that the activation occurs at the transcriptional level.

Mol Biol (Mosk), 1978 Sep-Oct, 12(5), 1050 - 6
{Unwinding effect of F1 gene 5 protein on double-stranded polynucleotides and DNA}; Permogorov VI et al.; The effect of gene 5 protein from bacteriophage f1 on melting of double-stranded polynucleotides and DNAs has been investigated using the UV-spectroscopy method . A dependence of the melting temperature of polynucleotide (DNA)-gene 5 protein complexes upon the polynucleotide (DNA) GC-pair content has been detected . Using experimental data and examining some model systems we came to the supposition that the lowering of melting temperature of polynucleotide (DNA) induced by this protein is probably stipulated by intercalation of the protein tyrosyl residues into one of the chains of polynucleotide (DNA) double helix.

Biophys Chem, 1978 Sep, 8(4), 281 - 94
Analysis of ion concentration effects of the kinetics of protein-nucleic acid interactions . Application to lac repressor-operator interactions; Lohman TM et al.; The effects of monovalent and divalent cations on the bimolecular rate constant of the reaction of a positively charged ligand with a nucleic acid polyanion are analyzed for two possible reaction mechanisms . One mechanism postulates that the association reaction occurs without intermediates, and that ion effects on the rate constant result entirely from the screening of the charged reactants by ionic atmospheres of low molecular weight ions (a screening-controlled mechanism) . This mechanism is analyzed by analogy with the Bronsted-Bjerrum theory for the kinetics of interaction of low molecular weight ions . The second mechanism to be considered here postulates the existence of a ligand-DNA intermediate which is in rapid equilibrium with the reactants (pre-equilibrium mechanism) . Ion concentration effects on the association rate constants for the pre-equilibrium mechanism result mainly from the release of counterions from the DNA upon formation of the intermediate . Both of the above mechanisms predict that the logarithm of the association rate constant, ka, will be a linear function of the logarithm of the monovalent cation concentration, {M+} (in the absence of competition by divalent cations or anions) . Knowledge of the salt dependences of ka and of the observed equilibrium constance Kobs of the ligand-nucleic acid interaction should usually be sufficient to determine whether a screening controlled mechanism or a pre-equilibrium mechanism is suitable to describe the process . If the association reaction can be described by a pre-equilibrium mechanism, the number of ionic interactions involved in the ligand-nucleic acid intermediate can be estimated . This analysis, extended to include the effects of divalent cations on screening or on the pre-equilibrium step, is applied to literature data on the salt dependence of the kinetics of the interaction of lac repressor with lac operator DNA . When the operator is present on bacteriophage lambda DNA, the observed reaction kinetics are consistent with the formation of an intermediate repressor-DNA complex in a pre-equilibrium step . On the other hand, the kinetics of association of lac repressor with synthetic lac operator fragments may be an example of a screening-controlled reaction.

Biokhimiia, 1978 Sep, 43(9), 1563 - 77
{Interaction between sodium bisulfite and bacteriophage SD DNA}; Skliadneva VB et al.; The interaction between sodium bisulfite and the cytosine residues within the intraphage DNA of phage SD was studied to elucidate the structure of viral nucleoprotein . Hydrolysis with perchloric acid of bisulfite-modified phage SD results in 18% decrease of cytosine and appearance of products having the properties of cytosyl amino acids (most probably cytosyl lysine) . When the modified phage before hydrolysis was subjected to mild destruction in 0.1--1 M NaCl or Tris-HCl buffer (pH 7.0), neither the decrease of cytosine nor the appearance of cytosyl peptides was observed . However, these results were observed when the phage was heated at 70 degrees C in a medium containing 0.05 M phosphate buffer, pH 7.9--8.5 . The presence of cytosyl amino acids in the modified phage, representing nucleotide-protein covalent cross-links explains the results of viscosometry and centrifugation in CS2SO4 density gradient . It is assumed that the bisulfite reaction with cytosine within phage SD is completed at the stage of intermediate product formation, i.e . C5--C6-dihydro-C6-sulfopyrimidine, in which the amino group is screened by interaction with protein (product VII) . This product may exist only in situ; when the phage nucleoprotein is destroyed in phsophate-free media, product VII is converted into original cytosine . Under acidic hydrolysis or in the presence of phosphate ions under heating, product VII undergoes transamination accompanied by SO3 split-off and reconstitution of C5--C6 double bond to form cytosylamino acids.

Nucleic Acids Res, 1978 Sep, 5(9), 3209 - 18
Determination of the endpoints of partial deletion mutants of the attachment site of bacteriophage lambda by DNA sequencing; Davies RW et al.; The deletion mutants b508 and b522 of bacteriophage lambda both end within the attachment site . The formation of such deletions is dependent upon the presence of intact integrase, and thus the deletion endpoints may be related to the normal crossover site in site-specific recombination . We have determined the DNA sequences of the attachment site regions of these deletions . Comparison of the sequences with lambda wildtype shows that both the deletions end within the central common homology region but at different positions . The consequences of these findings for current models of site-specific recombination are discussed.

Nucleic Acids Res, 1978 Sep, 5(9), 3141 - 56
Nucleotide sequence of the O gene and of the origin of replication in bacteriophage lambda DNA; Scherer G; The nucleotide sequence of the O gene in bacteriophage lambda DNA is presented . According to two possible initiator codons, the primary structure of the O protein deduced from the DNA sequence consists of 278 or 299 amino acid residues . Structure and function of the O protein--one of the two phage initiator proteins for lambda DNA replication--are discussed in the light of a secondary structure model for the O protein . The central part of the O gene contains a cluster of symmetrical sequences extending over 160 base pairs . The point mutation of the cis-dominant replication mutant ti12 is located in this region.

J Virol, 1978 Sep, 27(3), 835 - 7
Absence of phospholipase activity in bacteriophage T4; Thiel T et al.; We assayed phospholipase activity in T4Dt+ and in t mutant phage grown under permissive and restrictive conditions . There was no correlation between the presence of the t+ gene product and phospholipase activity . Phospholipase activity in phage lysates could be attributed to the presence of bacterial debris or to the use of commercial DNase which contains phospholipase.

J Virol, 1978 Sep, 27(3), 745 - 53
Evolution of bacteriophage phi C174 . V . Alignment of the phi X174, G4, and St-1 restriction enzyme cleavage maps; Grindley JN et al.; The restriciton enzyme cleavage maps of bacteriophage phiS174, G4, and St-1 were aligned by two-dimensional filter hybridization . These studies show that the basic genome structure of phiX174 is conserved in the other two bacteriophage . However, the data also suggest the existence of regions of nonhomology.

J Virol, 1978 Sep, 27(3), 738 - 44
Evolution of bacteriophage phi X174 . IV . Restriction enzyme cleavage map of St-1; Grindley JN et al.; 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.

J Virol, 1978 Sep, 27(3), 513 - 8
Genetic characterization of Mu-like bacteriophage D108; Hull RA et al.; Infection of Escherichia coli by bacteriophage D108 was shown to result in the generation of apparently random chromosomal mutations . Approximately 1% of the cells lysogenized by D108, as with Mu, acquired new auxotrophic mutations . D108-induced mutations were nonreverting and were most probably the result of insertion of the D108 genome into regions of genetic function . D108 and Mu shared many similar properties but were heteroimmune and had different host ranges . Lytic infections of Mu lysogens with D108 and D108 lysogens with Mu resulted in 100-fold increases in release of phage with prophage markers over those due to spontaneous induction . Phenotypic mixing was common, with most phage carrying the prophage immunity being packaged in particles with the host range of the superinfecting phage . A fraction of the superinfecting phage genomes were, however, packaged in particles with the prophage-specified host range . Although 10% of the prophage progeny were D108-Mu genetic hybrids, superinfecting phage-induced release of the prophage with reciprocal phenotypic mixing occurred in recA hosts, in which the frequency of D108-Mu genetic hybrids was reduced 100-fold.

J Gen Virol, 1978 Sep, 40(3), 705 - 9
Specificity of partial exclusion of bacteriophage T2 in crosses with T4; Okker RJ et al.; An attempt was made to isolate a bacteriophage T4 mutant generally disturbed in its ability to exclude the localized exclusion sensitivity determinants of T2 from the progeny of crosses . The method used was a modification of that used previously, which revealed T4 mutants unable to exclude more than one of the T2 sensitive sites specifically . One out of 1000 isolates from a mutagenized T4 am56:am32 stock was found to be mutated in its exclusion properties . However, the mutant was not generally exclusion deficient . Its properties were similar to those of a double mutant T4 ex 56:ex32, specifically unable to exclude the T2 sensitive sites near gene 56 and gene 32 . The failure to isolate a generally excluding mutant at a frequency down to 10(-3) renders the occurrence of a general exclusion locus unlikely.

Genetika, 1978 Sep, 14(9), 1513 - 20
{Effect of semipermissive conditions on recombination involving the early genes of bacteriophage T4 in amber-mutants . I . Effect of amber-mutation in gene 43}; Gordeev VK et al.; Recombination frequencies between rII markers of bacteriophage T4 under conditions of partial inhibition of several early functions of the phage by amber mutations have been studied . Mutations in genes 33, 42 and 45 did not affect significantly recombination frequencies . Mutations in genes 32, 44 and 46 inhibited it . It has been found that effects of double mutations in pairs of genes: 43 and 30; 43 and 52; 43 and 33; 43 and 46; 43 and 32 were consistent with theoretically expected additive effects of corresponding single mutations . The presence of double mutations in pairs of genes: 43 and 41; 43 and 42, 43 and 44, 43 and 45 caused evident deviations from additivity . These deviations could reflect specific interactions of respective pairs of genes products under phage T4 recombination . Possible mechanisms of some of the effects observed are discussed.

Proc Natl Acad Sci U S A, 1978 Sep, 75(9), 4470 - 3
Mutants of Escherichia coli altered in both genes coding for the elongation factor Tu; Van de Klundert JA et al.; Genetic analysis of a mutant of Escherichia coli resistant to the antibiotic mocimycin is presented . This resistance is due to alterations in both tuf genes coding for the elongation factor Tu . Mocimycin resistance is recessive . Bacteria carryong only one tuf gene from the resistant mutant are still mocimycin sensitive . If the mutant gene is the tufA gene, the seisitive cells can be made resistant through inactivation of the tufB gene by insertion of the bacteriophage milliunits genome . Conditional mocimycin-resistant mutants ban also be isolated when the tufB gene is altered by an amber or a temperature-sensitive mutation . When only the tufB allele from the original mocimycin-resistant mutant is present, inactivation of the wild-type tufA gene fails to give viable mocimycin-resistant progeny . We conclude that the tufA mutant allele codes for a functional mocimycin-resistant EF-Tu, whereas the mutant tufB gene does not code for a functional product.

Proc Natl Acad Sci U S A, 1978 Sep, 75(9), 4242 - 6
Cosmids: a type of plasmid gene-cloning vector that is packageable in vitro in bacteriophage lambda heads; Collins J et al.; Evidence is presented that ColE1 hybrid plasmids carrying the cohesive-end site (cos) of lambda can be used as gene cloning vectors in conjunction with the lambda in vitro packaging system of Hohn and Murray {(1977) Proc . Natl . Acad . Sci . USA 74, 3259--3263} . Due to the requirement for a large DNA molecule for efficient packaging, there is a direct selection for hybrids carrying large sections of foreign DNA . The small vector plasmids do not contribute a large background in the transduced population, which is therefore markedly enriched for large hybrid plasmids (over 90%) . The efficiency of the in vitro packaging system is on the order of 10(5) hybrid clones per microgram of foreign DNA for hybrids in the 20--30 million dalton range.

Nucleic Acids Res, 1978 Sep, 5(9), 3347 - 56
Apurinic endonucleases from Saccharomyces cerevisiae; Armel PR et al.; Three endonuclease activities have been partially purified from Saccharomyces cerevisiae on the basis of their activity against x-irradiated closed-circular supercoiled bacteriophage PM2 DNA . These endonucleases also nick apurinic DNA and two out of the three activities incise DNA UV-irradiated with high doses . The endonuclease activities have also been distinguished on the basis of their magnesium requirement and sensitivity to EDTA.

J Virol, 1978 Sep, 27(3), 815 - 8
Isolation of a bacterial host selective for bacteriophage T4 containing cytosine in its DNA; Runnels J et al.; An Escherichia coli B strain, B834 galU56, has been isolated which supports growth of bacteriophage T4 with cytosine in its DNA while restricting growth of T4 with hydroxymethylcytosine . This host is partially deficient in uridine diphosphoglucose as determined by the ability of DNA isolated from T4 grown on it to accept glucose in an in vitro assay . In this mutant an intact rgl restriction system recognizes unglucosylated hydroxymethylcytosine residues in phage DNA, while the absence of a functional rB restriction function prevents degradation of unmodified DNA containing cytosine.

J Virol, 1978 Sep, 27(3), 677 - 87
Localization of Escherichia coli RNA polymerase binding sites on bacteriophage S13 and phiX174 DNA: alignment with restriction enzyme maps; Rassart E et al.; Escherichia coli RNA polymerase has been shown to bind to a limited number of Hind and Hae III restriction enzyme fragments . On S13 replicative form DNA there are three major binding sites, and the locations correlate with promoter sites at the beginning of genes a and B and a site overlapping gene D and the beginning of gene E . Two less definite binding sites have been localized, one in gene F and one at the gene G-H junction . In phiX174 replicative form DNA, five sites, each with apparently similar binding properties, have been located, four of which correspond exactly to binding sites in S13 . One site, at the beginning of the B gene, could not be assigned to exactly the same location found in S13 . This was due in part to differences in the restriction cleavage maps in the area of the DNA and possibly to the higher background of nonspecific binding in the phiX174 experiments . The location of two of the phiX174 sites at the beginning of genes A and D-E corresponds very well with transcription data, but the site at the start of the B gene indicates the promoter site is closer to the initiation sequence of the B protein than was previously suggested on the basis of transcription data.

J Gen Microbiol, 1978 Sep, 108(1), 141 - 9
Serological characteristics of pili determined by the plasmids R711b and F0lac; Bradley DE et al.; The plasmids R711b (at present IncX) and F0lac (IncFV) both determine pili morphologically like those of F (IncFI), and confer sensitivity to the F-specific filamentous bacteriophages, but not to the F-specific isometric RNA phages . Detailed serological studies show that the two pilus types are unrelated, and that neither is related to any of the previously defined F pilus serotypes . Adsorption of the isometric RNA phage MS2 to R711b pili occurs in the presence but not in the absence of formalin, which presumably prevents elution of reversibly adsorbed virions . No adsorption occurs with F0lac pili . MS2 multiplication, as measured by titre increase tests in liquid medium, is found with neither plasmid . The two plasmids are not incompatible . These observations indicate that R744b and F0lac are different both from one another and from the plasmids belonging to the incompatibility groups IncFI--IV.

Proc Natl Acad Sci U S A, 1978 Sep, 75(9), 4268 - 70
Efficient correction of a mutation by use of chemically synthesized DNA; Razin A et al.; 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 position 587 on the phiX174 DNA sequence, was used to infect spheroplasts . The progeny phage were analyzed by a parallel plaque assay on wild-type host, Escherichia coli C, to screen for wild-type phenotype, and on E . coli HF4714, an amber suppressor strain, to determine the total progeny phage . When a 23-base-long synthetic primer was used, about one-third of total progeny were found to be wild type . Shorter primers yielded lower percentages of wild type; they also had poorer priming activity.

Proc Natl Acad Sci U S A, 1978 Sep, 75(9), 4165 - 9
Kinetic factors and form determination of the head of bacteriophage T4; Showe MK et al.; The form of the bacteriophage T4 prehead is described by its icosahedral symmetry, its diameter, and its length . We show how each of these parameters is regulated during prehead formation and ascribe specific form-determining functions to the prehead proteins . The major protein of the head shell can assemble in several different forms . The structure produced in vivo depends on the rate of synthesis of the major protein relative to the rates of synthesis of minor shell proteins and the major core protein . From our observations, we propose a model for form determination of the prehead and suggest a pathway for the evolution of its prolate shape.

J Bacteriol, 1978 Sep, 135(3), 883 - 7
Effect of membrane-associated f1 bacteriophage coat protein upon the activity of Escherichia coli phosphatidylserine synthetase; Chamberlain BK et al.; The effects of insertion of the major coat protein of f1 bacteriophage into Escherichia coli membranes were investigated under conditions allowing in vivo analysis of phosphatidylserine synthesis . An E . coli strain possessing a temperature-sensitive phosphatidylserine decarboxylase was utilized under conditions in which the decarboxylase activity was reduced but nonlethal . The presence of the coat protein in the host membranes inhibits the activity of the phosphatidylserine synthetase and perhaps affects the activity of the phosphatidylserine decarboxylase.

J Virol, 1978 Sep, 27(3), 483 - 9
Bacteriophage SPO1 development: defects in a gene 31 mutant; Sarachu AN et al.; SPO1 temperature-sensitive mutant ts14-1, located in cistron 31, has a DD (DNA synthesis-delayed) phenotype at 37 degrees C and produces progeny in a stretched program . At 44 degrees C it behaves as a DO (DNA synthesis-defective) mutant and shuts off the viral RNA synthesis about 10 min after infection . The thermal sensitivity of this mutant is due to the inactivity of gp-31 (the product of gene 31) at 44 degrees C . However, gp-31 is synthesized at that temperature and partly recovers its activity at 37 degrees C . Only 5 min at the permissive temperature is enough to trigger the continuation of the phage program and to produce progeny . The partial defect at 37 degrees C and the expansion of the middle program together with the pleiotropic defects at the nonpermissive temperature could be suitable for the study of the controls involved in bacteriophage development.

J Gen Microbiol, 1978 Sep, 108(1), 1 - 7
The correlation of bacteriophage types of Mycobacterium tuberculosis with guinea-pig virulence and in vitro-indicators of virulence; Grange JM et al.; Among 58 isoniazid-sensitive strains of Mycobacterium tuberculosis from India, Burma and East Africa, 23 were of phage type A, 31 of type I (intermediate), 4 of type B and none of type C . Type I strains differed from type A strains in being attenuated in the guinea-pig, susceptible to H2O2, sensitive to thiophen-2-carboxylic acid hydrazide and resistant to thiacetazone and p-aminosalicylic acid; the content of strongly acidic lipids and of sulphatide lipids was low and the attenuation indicator lipid was present . The pattern of results with the type B strains did not correspond to the patterns for types A or I . Strains of type I appear to be a distinct group within the species M . tuberculosis.

Biochim Biophys Acta, 1978 Aug 23, 520(1), 61 - 9
Studies on sheep kidney nuclease . II . Limited digestion of phiX174 single-strand DNA; Watanabe T; 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 gradient centrifugation . The molecular weights of these DNA fragments were 1.7 . 10(6), 1.2 . 10(6), 8.6 . 10(5), 4.5 . 10(5) and 2.8 . 10(5) . From the melting curves and the base compositions of these fragments it was suggested that phiX174 single-strand DNA might have intramolecular double helical regions, which were hardly susceptible to attack by nuclease SK.

Biochemistry, 1978 Aug 22, 17(17), 3474 - 9
Identification of the transcribing DNA strand for the deoxynucleotide kinase gene of bacteriophage T2; Trimble RB et al.; A modified procedure was developed which allows RNA--DNA hybridization reactions to be performed without the loss in translational capacity of mRNA which accompanies hybridization at elevated temperatures or in the presence of the denaturing agent formamide . Separated l and r strands of bacteriophage T2 DNA were hybridized in the presence of 4 M sodium perchlorate at 37 degrees C with total RNA from infected cells . After passage of the hybridization mixture through a nitrocellulose column to remove single-strand DNA and DNA--RNA hybrids, the eluent was measured for its capacity to promote deoxynucleotide kinase (gene 1) synthesis in an in vitro protein-synthesizing system derived from uninfected Escherichia coli . With this procedure, which should be of general use for any message whose product can be measured either enzymatically, immunologically, or by location in an acrylamide gel, it was demonstrated that deoxynucleotide kinase mRNA is transcribed from the l strand of bacteriophage T2 DNA . By titrating with l strand DNA, the number of deoxynucleotide kinase transcripts present 9 min after T2 phage infection at 30 degrees C was estimated to be about 38 copies per cell.

Mol Gen Genet, 1978 Aug 17, 164(2), 131 - 5
Major outer membrane proteins of E . coli K12 serve as receptors for the phages T2 (protein Ia) and 434 (protein Ib); Hantke K; Mutants of E . coli resistant to bacteriophage T2 have lowered amounts of protein Ia in their outer membrane . Bacteriophage T2 was inactivated by a mixture of protein Ia-lipopolysaccharide . Protein Ia or lipopolysaccharide alone had no neutralizing activity . However, only protein Ia was required to inactivate a T2 host range mutant . In the presence of polymyxin B T2 receptor activity of protein Ia--lipopolysaccharide mixtures could not be restored . E . coli strains missing protein Ib were resistant against the lambdoid phage 434 . Purified protein Ib inactivated 434 and lambdavirh434 . Addition of lipopolysaccharide did not enhance the neutralizing activity of protein Ib, indicating that lipopolysaccharide may not be necessary for the inactivation of the phage.

Nature, 1978 Aug 10, 274(5671), 553 - 8
Nucleotide sequences at the ends of bacteriophage Mu DNA; Allet B; The nucleotide sequences were analysed at the two ends of bacteriophage Mu DNA . Such analyses reveal the existence of a short stretch of common sequences that are located at the termini and are orientated as inverted repeats . They also confirm that the heterogeneous bacterial DNA covalently bound to the ends of vegetative Mu DNA is totally removed during lysogenisation.

J Biol Chem, 1978 Aug 10, 253(15), 5548 - 50
Zinc uptake and incorporation into proteins in T4D bacteriophage-infected Escherichia coli; Kozloff LM et al.; The metabolism of Zn2+ in Escherichia coli infected with T4D bacteriophage and various T4D mutants has been examined . E . coli B infected with T4D, and all T4D mutants except T4D 12-, took up zinc ions at a rate identical to that of uninfected cells . E . coli B infected with T4D 12- had a markedly decreased rate of zinc uptake . The incorporation of zinc into proteins of infected cells has also been studied . T4D phage infection was found to shut off the synthesis of all bacterial host zinc metalloproteins while allowing the formation of viral-induced zinc proteins . The amount of zinc incorporated into viral proteins was affected by the absence of various T4D gene products . Cells infected with T4D 12-, and to a much less extent those infected with T4D 29-, incorporated the least amount of zinc into proteins, while cells infected with T4D 11- and T4D 51- incorporated increased amounts of zinc into the zinc metalloproteins . In cells infected with T4D 11- and 51- most of the zinc protein was found to be the product of gene 12 . The marked effect of infection of E . coli with T4D 12- on both zinc uptake and zinc incorporation into protein supports the conclusion that T4D gene 12 protein is a zinc metalloprotein . Additionally, these observations have indicated that this metalloprotein interacts with host cell membrane.

Mol Gen Genet, 1978 Aug 4, 164(1), 63 - 76
Control of lambda repressor prophage and establishment transcription by the product of gene tof; Hayes S et al.; Control of expression of the bacteriophage lambda (lambda) repressor was studied by measuring repressor transcription in noninduced and derepressed lambda lysogens . Three distinct modes of leftward transcription were observed from cI and the adjacent genes associated with the control of repressor synthesis: The prophage or maintenance mode Prm-cI-rex-ti repressor transcript occurs from repressed lysogens; the oop (Po-oop-to) transcript, and the lit (lit-ti) RNA, from the distal half of gene rex, both occur from induced tof+ prophage; the repressor establishment mode of transcription is observed throughout the rex-cI-tof-y-cII-oop interval between Po and ti from induced tof- prophage . The overall level of establishment mRNA synthesis is partially template dependent . However, the actual initiation step for repressor establishment transcription requires the participation of the lambda cIII, cII products, and also either requires the activity of Escherichia coli replication proteins, or is triggered by a replication initiation event . The cII cIII products do not positively stimulate de novo initiation of establishment transcription, but rather act after an initial replication-dependent step . Initiation of the establishment mode of repressor transcription is totally inhibited by more than 125-fold, in an all or none fashion, by the lambda antirepressor (Tof), the product of gene tof (cro) . Since Tof only reduces the in vivo rightward transcription of cII from Pr by about 2-fold, we suggest that Tof inhibits repressor establishment transcription by either uncoupling the replication and cII-cIII dependent events, or by inhibiting the activity rather than the expression of the cIII, cII products . Our results do not fully support either of the present hypotheses that establishment transcription is initiated from the hypothetical Pre promoter in the y-interval, or arises through antitermination of the oop RNA . Since the initiation and control of the establishment mode of repressor transcription parallels the control of lit RNA synthesis, we propose a common mechanism underlies the initiation of these transcripts.

Mol Gen Genet, 1978 Aug 4, 164(1), 9 - 14
Genetic analysis of two genes, dnaJ and dnaK, necessary for Escherichia coli and bacteriophage lambda DNA replication; Yochem J et al.; We show that a collection of 93 E . coli mutations which map between thr and leu and which block phage lambda DNA replication define two closely linked cistrons . Work published in the accompanying paper shows that these mutations also affect host DNA replication, so we designate them dnaJ and dnaK; the gene order is thr--dnaK--dnaJ--leu . Demonstration of two cistrons was possible with the isolation of lambda transducing phages carrying one or the other or both of the dna genes . These phages were employed in phage vs bacterial complementation studies which unambiguously show that dnaK and dnaJ are different cistrons.

Nucleic Acids Res, 1978 Aug, 5(8), 2895 - 912
Expression of bacteriophage M13 DNA in vivo . Localization of the transcription initiation and termination signal of the mRNA coding for the major capsid protein; Rivera MJ et al.; During the infection cycle of the filamentous bacteriophage M13 a phage specific RNA species is made which selectively directs in vitro the synthesis of the precursor of the major capsid protein encoded by gene VIII . This RNA is unstable (its mean half-life is 11 min) and is made in amounts representing at least 2% of the newly synthesized RN . Nucleotide sequence analysis have indicated that the synthesis of this RNA species is initiated and terminated at the same promoter (G0.18) and termination signal (T0.25) of the M13 genome as the 8S RNA species made in vitro under the direction of M13 replicative form DNA.

J Virol, 1978 Aug, 27(2), 409 - 26
Isolation and characterization of bacteriophage T4 mutant preheads; Onorato L et al.; To determine the function of individual gene products in the assembly and maturation of the T4 prehead, we have isolated and characterized aberrant preheads produced by mutations in three of the T4 head genes . Mutants in gene 21, which codes for the T4 maturation proteases, produce rather stable preheads whose morphology and protein composition are consistent with a wild-type prehead blocked in the maturation cleavages . Mutants in gene 24 produce similar structures which are unstable because they have gaps at all of their icosahedral vertices except the membrane attachment site . In addition, greatly elongated "giant preheads" are produced, suggesting that in the absence of P24 at the vertices, the distal cap of the prehead is unstable, allowing abnormal elongation of broth the prehead core and its shell . Vertex completion by P24 is required to allow the maturation cleavages to occur, and 24- preheads can be matured to capsids in vitro by the addition of P24 . Preheads produced by a temperature-sensitive mutant in gene 23 are deficient in core proteins . We show that the shell of these preheads has the expanded lattice characteristic of the mature capsid as well as the binding sites for the proteins hoc and soc, even though none of the maturation cleavage takes place . We also show that 21- preheads composed of wild-type P23 can be expanded in vitro without cleavage.

Genetika, 1978 Aug, 14(8), 1466 - 9
{Coding R.M.EcoR1-plasmids derived from R-factor}; Aleshkin GI et al.; Bacteriophages P1vir and Mu-1 have been used for transductional shortening of recombinant R factor coding for R.M.EcoR1 isolated by Yoshimori et al . P1 shortening made possible the isolation of transmissive isogenic plasmids coding R.M.EcoR1 and differing in antibiotic resistances, as well as isolation of plasmids differing only in R.M.EcoR1 genes . Mu-1 mediated shortening favoured the isolation of transmissive R plasmids having lost the resistance to chloramphenicol but having all other markers of recombinant R factor intact . The data are interpreted in support of Yoshimori et al . supposition concerning the existence of R.M.EcoR1 coding recombinant R factor of Escherichia coli.

J Bacteriol, 1978 Aug, 135(2), 445 - 52
Functional organization of the kdp genes of Escherichia coli K-12; Rhoads DB et al.; The kdp genes code for a high-affinity and repressible K+ transport system . The regulation and organization of the kdp genes were analyzed by studies of constitutive mutants and of strains in which bacteriophage lambda is integrated into the kdp genes . The polar effects of lambda integration demonstrate that three of the kdp genes form an operon, kdpABC, read from A to C . The kdpD gene is a separate transcription unit and is the site of mutations making expression of the kdp genes partially constitutive . The constitutive mutants are dominant to kdpD+ in diploids . These findings, the fact that kdpD mutations identified previously are Kdp-, and the existence of intracistronic complementation between some kdpD mutations indicate that the kdpD gene product is an oligomeric positive regulator of the kdp genes . Deletions extending clockwise from kdp as far as the gltA locus were isolated from strains with bacteriophage lambda integrated into kdpD . Plaque-forming transducing lambda phages carrying the kdpABC operon were isolated.

Nucleic Acids Res, 1978 Aug, 5(8), 2991 - 7
Substrate dependence of the mechanism of EcoRI endonuclease; Rubin RA et al.; The mechanism of EcoRI endonuclease is substrate dependent . At 37 degrees dissociation of the enzyme-Form II DNA intermediates of ColE1 DNA and bacteriophage G4 RFI DNA is negligible . Therefore, both DNA strands with in the EcoRI sequence are cleaved during a single binding event . However, double strand cleavage of SV40 DNA occurs without dissociation of the enzyme in only 75% of the catalytic events . This mechanistic difference presumably reflects sequence differences about the EcoRI sites of these DNA's.

Nucleic Acids Res, 1978 Aug, 5(8), 2743 - 54
Electrophoretic strand separation of long DNAs with poly (U,G) in agarose gels; Goldbach RW et al.; We have found that binding of poly(U,G) to single-stranded DNA decreases its mobility in 0.3% agarose gels . Differential binding to the complementary strands of denatured duplex DNA provides a simple method for strand separation . The method is shown to work with bacteriophage lambda DNA, adenovirus DNA and mtDNA for Tetrahymena pyriformis . In all cases the strand that binds more poly(U,G) in CsCl gradients also binds more in gels . The separated strands can be directly blotted from the gel onto nitrocellulose filters and used for hybridization experiments.

J Biol Chem, 1978 Jul 25, 253(14), 5048 - 55
Function of phospholipids in Escherichia coli . Characterization of a mutant deficient in cardiolipin synthesis; Pluschke G et al.; Screening of a collection of temperature-sensitive mutants of Escherichia coli for defects in phospholipid metabolism led to the isolation of a mutant deficient in cardiolipin synthesis . The defective gene, named cls, is closely linked to the trp marker and maps at about Minute 27 on the E . coli chromosome . After transfer of cls to a defined genetic background by transduction, the mutant has the following properties as compared to an isogenic wild type . Exponentially growing cells show a reduction in cardiolipin content by a factor of at least 15 (less than 0.2 mol % of the total phospholipids) . A crude membrane fraction derived from the mutant is unable to synthesize cardiolipin from phosphatidylglycerol in vitro . The mutant has no distinctive phenotype regarding its growth properties, membrane-associated respiratory functions, or the ability to insert bacteriophage M13 coat protein into the cell envelope . The cls mutation confers a 5-times reduction in the turnover of the phosphate moiety of phosphatidylglycerol.

J Biol Chem, 1978 Jul 25, 253(14), 5174 - 9
An ATP stimulation of T4 DNA polymerase mediated via T4 gene 44/62 and 45 proteins . The requirement for ATP hydrolysis; Piperno JR et al.; An in vitro replication system reconstituted from six purified T4 bacteriophage proteins, each of which is essential for T4 DNA replication in vivo, requires ATP . Because of the complexity of the complete system, we examine in this report the involvement of ATP in two subsystems of the overall DNA synthesis reaction . One subsystem consists of the T4 DNA polymerase (gene 43 protein) and its "accessory proteins," the gene 44/62 and 45 products . An even simpler subsystem consists of the gene 44/62 and 45 proteins alone, which together have a DNA-dependent ATPase activity . The combination of the 44/62 and 45 proteins hydrolyze ATP to ADP and inorganic phosphate in the presence of DNA . These essential accessory proteins have been previously shown to increase T4 DNA polymerase activity on primed, single-stranded DNA templates . In this report we use nucleotide analogues to demonstrate that this polymerase stimulation requires hydrolysis of the beta,gamma-phosphate bond of ATP . However, our data suggest that the mechanism of accessory protein stimulation is such that less than 1 ATP molecule need be hydrolyzed per 10 deoxyribonucleotides incorporated by the DNA polymerase into DNA.

Eur J Biochem, 1978 Jul 17, 88(1), 109 - 17
Transcription of bacteriophage T4 DNA in vitro: selective initiation with dinucleotides; Ruger W; The transcription products of phage T4 DNA in vitro are separated on polyacrylamide gels . The influence of salt, polymerase, triphosphate concentration and glucosylation on the RNA synthesis are shown . Individual transcripts are initiated selectively with dinucleotides and a single triphosphate . This technique allows the prediction of the initiation sequences of several T4 transcripts.

Nature, 1978 Jul 6, 274(5666), 34 - 7
Potential for variability through multiple gene products of bacteriophage phiX174; Pollock TJ et al.; 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.

Gene, 1978 Jul, 3(4), 293 - 302
Physical mapping of cleavage sites recognized by restriction endonucleases on the genome of bacteriophage T5; Tchernov AP et al.; The DNA of bacteriophage T5 has been treated with restriction endonucleases EcoRI, HindIII, BamI, SmaI, PstI, SalI, KpnI and the electrophoretic pattern obtained in agarose gel has been analyzed in order to localize the specific cleavage sites on the T5 DNA . The localization of cleavage sites has been reduced from the electrophoretic pattern of double and partial digests, the digests of isolated restriction fragments and the digests of deletion mutant T5st(o) DNA . Four BamI cleavage sites have been found and localized on the physical map of T5 DNA at 0.21, 0.225, 0.685 and 0.725 fractional length . Endonuclease SmaI cleaves at 0.39, 0.59 and 0.69 fractional length . Endonuclease PstI cuts T5 DNA at 11 sites: 0.090, 0.210, 0.320, 0.510, 0.635, 0.670, 0.705, 0.770, 0.815, 0.840, 0.875 fractional length . Six KpnI cleavage sites have been mapped at 0.170, 0.215, 0.525, 0.755, 0.830, 0.850 fractional length . A complete cleavage map of the phage genome is presented for seven restriction enzymes.

Biokhimiia, 1978 Jul, 43(7), 1285 - 93
{Cleavage of bacteriophage PM2 DNA by S1 nuclease}; Gonikberg EM; The kinetics of cleavage of superhelical PM2 DNA by the single strand-specific S1 nuclease is studied at various salt concentrations (0.01--1 MNaCl) by electrophoresis in neutral and alkaline agarose gels . Cleavage of different DNA forms (superhelical DNA I, relaxed circular DNA II and linear DNA III) is described by the kinetic equations of the first order, and respective rate constants k1, k2, and k3 are determined at all salt concentrations used . It is shown that a high salt concentration (not lower than 0.2 MNaCl) is necessary for high specificity of S1 nuclease action on DNA regions with impaired base pairing . Examination of the S1 nuclease preparation action on superhelical PM2 DNA may be used as a convenient and reliable assay of its specificity.

J Virol, 1978 Jul, 27(1), 149 - 63
In vitro packaging of bacteriophate T7 DNA synthesized in vitro; Masker WE et al.; An in vitro DNA packaging system was used to encapsulate T7 DNA that had been synthesized by extracts prepared from gently lysed Escherchia coli infected with bacteriophage T7 carrying amber mutations in gene 3 or in both genes 3 and 6 . Isopycnic centrifugation of density-labeled wild-type DNA was employed in an effort to separate product from template; suppressor-free indicator bacteria were used to eliminate contributions from endogenous DNA or contaminating phage . Additional controls indicated that fragmented DNA is packaged in vitro only with very low efficiency and that the frequency of recombination during packaging is too low to affect interpretation of these experiments . T7 DNA replicated by extracts prepared using T7 mutants deficient in both genes 3 and 6 could be packaged in vitro with an efficiency comparable to that found when highly purified virion T7 DNA was used . When T7 deficient in the gene 3 endonuclease but with normal levels of the gene 6 exonuclease was used, fast-sedimentingconcatemer-like DNA structures were formed during in vitro DNA synthesis . Electron microscopy revealed many branched and highly complex DNA structures formed during this reaction . This concatemer-like DNA was encapsulated in vitro with an efficiency significantly greater than that found for DNA the length of a single T7 genome.

J Virol, 1978 Jul, 27(1), 103 - 17
New late gene, dar, involved in the replication of bacteriophage T4 DNA . III . DNA replicative intermediates of T4 dar and a gene 59 mutant suppressed by dar; Wu JR et al.; A mutation in the dar gene of phage T4 restored the arrested DNA synthesis caused by the gene 59 mutation . We have studied the DNA replicative intermediates in cells infected with a dar mutant and a dar-amC5 (gene 59) mutant by velocity sedimentation in neutral and alkaline sucrose gradients . In T4 dar-infected cells, compared to the wild type, three kinds of abnormalities were observed in DNA replication (i) There were unusually rapidly sedimenting intermediates (800S) . (ii) When centrifuged in alkaline gradients, there was less single-stranded DNA exceeding 1 phage unit . (iii) The rate of repair of DNA intermediates was slower . It has been proposed by others that the 200S DNA replicative intermediates are required for DNA packaging, but our results showed that the 800S DNA of dar does not have to be converted into the 200S form to undergo conversion to mature viral DNA . Therefore, 200S DNA may not be an obligatory intermediate for mature viral DNA formation . In amC5 (gene 59)-infected cells, the DNA was completely converted 2 to 3 min after intiation of replication to the biologically inactive 63S DNA, and DNA synthesis was concomitantly arrested . However, in dar-am-C5 (gene 59)-infected cells, the formation of abnormal 63S DNA did not occur and 200S DNA appeared instead . An endonucleolytic activity, normally associated with the cell membrane and capable of making double-stranded cuts, was found in the cytoplasm of T4 dar-infected cells . Because the total activity of this endonuclease is the same for both wild-type T4D and the dar mutant, it seems unlikely that the dar protein has endonucleolytic activity itself . However, the finding does explain the abnormal sedimentation of dar DNA intermediates (800S) as well as the proposed suppression mechanism of the gene 59 mutation.

Cell, 1978 Jul, 14(3), 559 - 68
The structural organization of DNA packaged within the heads of T4 wild-type, isometric and giant bacteriophages; Earnshaw WC et al.; We present electron microscopic and X-ray diffraction evidence concerning the structural organization of condensed DNA within a series of T4 bacteriophage with the following head morphologies: prolate (wild-type), isometric and giant (with greatly increased axial ratio) . In all cases, the DNA helix segments are locally parallel and 27 A apart . For the giant particles, we show that the DNA forms a large coil whose axis is perpendicular to the axis of the phage tail . This evidence, combined with previous results from a series of isometric bacteriophages (Earnshaw and Harrison, 1977), leads to a model for the organization of condensed DNA that may apply to most dsDNA-containing bacteriophages.

J Bacteriol, 1978 Jul, 135(1), 171 - 7
Isolation and characterization of a plaque-forming lambda bacteriophage carrying a ColE1 plasmid; Mukai T et al.; A plaque-forming lambdaimm434 bacteriophage carrying the entire genome of colicinogenic factor E1 has been isolated and characterized . This phage, lambdaimm434ColE1, can lysogenize as a stable plasmid within a recombination-deficient Escherichia coli cell that lacks the normal attachment site for lambda phage . Furthermore, it has been found that lambdaimm434ColE1 phage carrying amber mutations in the O and P genes of the lambda genome, i.e., lambdaimm434OamPamColE1, behaves as a plaque-forming phage, and this finding suggests that the ColE1 factor DNA permits replication of the DNA of the plaque-forming phage.

Gene, 1978 Jul, 3(4), 333 - 46
Heteroduplex electron microscopy of phage Mu mutants containing IS1 insertions and chloramphenicol resistance transposons; Chow LT et al.; We have examined by electron microscopy the DNA heteroduplexes of six bacteriophage Mu mutants, Mu X cam, generated by the insertion of the Tn9 transposon for chloramphenicol resistance . Tn9 was found to be 2.8 +/- 0.2 kilobases (kb) in length and to consist of a cam determinant flanked by two IS1 sequences arranged in a direct order . In two of the six Mu X cam mutants, the Tn9 insertion was at a fixed location, 3.9 kb from the left, or c, end . In the other four mutants, the position of the insertion varied, even though the lysogenic cultures induced were grown from single colonies . The insertion was located at either 3.3 kb, 3.9 kb, or, less frequently, at 4.4 kb from the left end of the DNA . Furthermore, at low frequencies, the insertions were found to be in an orientation opposite to what predominated in the preparation . Thus, Tn9 in the Mu X cam mutants examined could appear to undergo rapid rearrangements during Mu growth or over a few generations of cell growth . One of the Tn9 insertion sites was apparently the same as that for a 0.8 kb insertion found in a Mu X mutant . This latter insertion was identified as an IS1 sequence . The DNA molecules from all the Mu X cam mutant phage particles were found to be missing the bacterial DNA at the S (right) end, along with a variable amount of the adjoining Mu DNA in the beta region . This observation supports the headful packaging model for Mu DNA.

Gene, 1978 Jul, 3(4), 303 - 14
Insertion of a transposon for chloramphenicol resistance into bacteriophage Mu; Bukhari AI et al.; We have isolated mutants of bacteriophage Mu carrying the X mutations caused by the insertion of cam (Tn9), a transposon for chloramphenicol resistance . The Mu X cam mutants were obtained by selecting for heat-resistant survivors of a Mucts62, P1cam dilysogen . Like the previously described X mutants, Mu X cam mutants are defective prophages which can be excised from the host DNA at a frequency of 10(-5) to 10(-7) per cell . Tn9 insertions in Mu X cam mutants are located within 5000 base pairs of the left end of Mu DNA in a region that controls early replication functions of Mu . There is one EcoRI cleavage site in Tn9 . The Tn9 transposon itself can be excised precisely from the Mu X cam mutants to generate wild type Mu . In most Mu X cam mutants, precise excision of Tn9 occurs at a low frequency (10(-6) per cell), whereas in some, the frequency is higher (10(-4) per cell) . Mu X cam prophages can replicate after induction with the help of wild type Mu . The lysates containing Mu X cam particles, however, fail to transduce chloramphenicol resistance at a high frequency; Mu X cam mutants apparently have a cis dominant defect in integration.

Proc Natl Acad Sci U S A, 1978 Jul, 75(7), 3220 - 4
Novel template requirements of N4 virion RNA polymerase; Falco SC et al.; A DNA-dependent RNA polymerase has been purified from disrupted virions of the Escherichia coli bacteriophage N4 . The RNA polymerase is phage-coded and is required for class I N4 RNA synthesis, which is defined as RNA synthesized in vivo in the absence of post-infection protein synthesis . A polypeptide of molecular weight 350,000 is detected when the purified enzyme is analyzed by sodium dodecyl sulfate/polyacrylamide gel electrophoresis . N4 RNA polymerase requires denatured DNA as a template in vitro and shows a strong preference for denatured N4 DNA . With this template, transcription is asymmetric . The RNA product is complementary to only the H strand of N4 DNA . Furthermore, only class I N4 RNA is synthesized . In vivo transcription by the N4 virion RNA polymerase is inhibited by coumermycin . This result suggests that the activity of E . coli DNA gyrase, an enzyme that introduces negative supertwists into DNA, is required for N4 transcription.

Proc Natl Acad Sci U S A, 1978 Jul, 75(7), 3206 - 10
Visualization of the intracellular development of bacteriophage lambda, with special reference to DNA packaging; Yamagishi H et al.; To reveal intermediates in lambda DNA packaging, infected cells were osmotically ruptured and the cell lysates were deposited on electron microscope grids by sedimentation through a sucrose/formalin cushion . A fixation procedure that crosslinks head-related structures to DNA allowed us to study successive stages in the process of head filling . Three types of head-related structures can be distinguished: (i) empty heads (petit lambda), less angular in outline than complete lambda heads; (ii) heads partially filled with DNA (partially filled heads), having a roundish outline; and (iii) particles tightly packed with DNA (full heads), having a hexagonal outline . DNA-head complexes were bound either at the terminal end of a DNA thread or at a point intermediate along the thread . The terminal complexes were more abundant . No head-related structures could be found in an induced lambda mutant lysogen blocked in the synthesis of petit lambda (amber in lambda gene E) . One type of mutant blocked in DNA packaging (amber in gene A) produces empty heads and free tails, whereas another (amber in gene D) produces partially filled heads in addition . Our data suggest that a DNA-petit lambda complex may be an early intermediate in packaging and that the lambda DNA substrate can be a cohesive-ended concatemer or a concatemer with double-stranded cohesive site sequences.

J Bacteriol, 1978 Jul, 135(1), 207 - 14
Viral R plasmid Rphi6P: properties of the penicillinase plasmid prophage and the supercoiled, circular encapsidated genome; Tucker WT et al.; Properties of the viral R plasmid Rphi6P are described . As a temperate bacteriophage, it plaques on the facultative phototroph Rhodopseudomonas sphaeroides . Under aerobic conditions the phage had a latent period of 180 min, a burst time of 200 min, and a burst size of 15 to 20 particles per infective center . The encapsidated viral genome occurred as a supercoiled, circular DNA duplex with a mean contour length of 16.5 +/- 10 micron . Percent guanine plus cytosine, as calculated from thermal denaturation profiles, was 63.5 . Mitomycin C-induced loss of the prophage suggested an extrachromosomal location in the host cell . Use of this curing agent enabled the isolation of a plasmid-free strain of R . sphaeroides . Biophysical analysis of the plasmid-free strain lysogenized with Rphi6P confirmed that the prophage occurred as a plasmid in the host cell.

Proc Natl Acad Sci U S A, 1978 Jul, 75(7), 3094 - 8
Site-specific initiation of a DNA fragment: nucleotide sequence of the bacteriophage G4 negative-strand initiation site; Sims J et al.; The synthesis of the bacteriophage G4 negative strand is an example of the de novo initiation of a polynucleotide chain . This initiation is performed by the Escherichia coli replication protein dna G which selects a unique site on 5400-base positive-strand template . In this paper we present the nucleotide sequence of the G4 negative-strand initiation site . This is the template element recognized by the dna G priming protein . In conjunction with the sequence of the nascent negative strand, obtained by Bouche, Rowen, and Kornberg {Bouche, J.-P., Rowen, L . & Kornberg, A . (1978) J . Biol . Chem . 253, 765-769}, the present data provide a description of a dna G-dependent origin of replication in which one knows the place at which polymerization starts at the nucleotide level.

J Virol, 1978 Jul, 27(1), 90 - 102
New late gene, dar, involved in the replication of bacteriophage T4 DNA . II . Overproduction of DNA binding protein (gene 32 protein) and further characterization; Wu JR et al.; We have previously shown that the arrested DNA synthesis of mutant defective in T4 phage gene 59 can be reversed by a mutation in dar . In this paper, we have examined the effect of the dar mutation on the kinetics of gene 32 protein (DNA binding protein) synthesis, DNA packaging, progeny formation, and several other porcesses . Several lines of evidence are presented showing that the regulation of synthesis of gene 32 protein is abnormal in dar 1-infected cells . In these cells, gene 32 protein, an early protein, is also expressed late in the infectious cycle . Our data also indicate that the packaging og DNA into T4 phage heads is delayed in dar mutant-infected cells, and this in turn results in a 6- to 8-min delay in intracellular progeny formation, although the synthesis of late proteins appears to be normal, as shown by gel electrophoresis . We have also studied the phenotypes of the double mutant dar-amC5 (gene 59) . The increased sensitivity to hydroxyurea caused by a mutation in the dar gene can be alleviated by a second mutation in gene 59, but an increased sensitivity to UV irradiation caused by a mutation in gene 59 cannot be alleviated by a second mutation in the dar gene . Therefore, the double mutant still exhibits abnormalities in the repair of UV lesions.

J Bacteriol, 1978 Jul, 135(1), 164 - 70
Two bacteriophages which utilize a new Escherichia coli major outer membrane protein as part of their receptor; Chai TJ et al.; Escherichia coli strain JF694 contains a new major outer membrane protein which we have called protein E (J . Foulds, and T . Chai, J . Bacteriol . 133:1478-1483) . Two new bacteriophages, TC45 and TC23, were isolated that require the presence of protein E in the outer membrane of host cells for growth . Both of these bacteriophages have a morphology similar to T-even bacteriophages but are distinct in properties such as plaque morphology, buoyant density, and burst size . Although strain JF694, containing protein E, adsorbs bacteriophage TC45 efficiently, cells killed with heat or chloroform are unable to inactivate this bacteriophage . Purified protein E either in the presence or absence of additional probable cofactors such as lipopolysaccharide was also unable to inactivate bacteriophage TC45 . Both bacteriophages probably use protein E as at least part of their receptor but require, in addition, other outer membrane components or a specific orientation or organization of this protein in the outer membrane.

Mol Biol (Mosk), 1978 Jul-Aug, 12(4), 937 - 46
{Antigenic structure of bacteriophage lambda . Identification of the chief antigens of bacteriophage lambda}; Ivanov VN et al.; The antigenic composition of the bacteriophages lambdaC1857 and lambdagt-lambdaC was investigated by modified immunoelectrophoresis in a 1,2% agarose gel involving 1% Triton X-100 and 0,25% sodium desoxycholate . The phages lambdaC1857 and lambdagt-lambdaC were shown to have identical antigenic compositions and to comprise three basic antigens, such as a1, a2, a3 . The main structural proteins of the phage such as pE, pV and pD were isolated by preparative electrophoresis in 13% polyacrilamide gel . The immunophoresis of individual proteins indicated the antigens a1, a2 and a3 to be proteins pV, pD and pE, respectively.

Appl Environ Microbiol, 1978 Jul, 36(1), 52 - 55
Characteristics of bacteriophages for Micromonospora purpurea; Kikuchi M et al.; Chemical and physical stabilities of bacteriophages oUW 21 and oUW 51 infecting Micromonospora purpurea ATCC 15835 were examined . Both phages were stable over the pH range of 5 to 8 and to heating at temperatures up to 50 degrees C and especially stable in buffer containing magnesium ion . Exposure to 1 M Ca(NO3)2 inactivated both phages, and phage oUW 51 was also susceptible to 1 M CaCl2, 0.1 M tris(hydroxymethyl)aminomethane, and 0.3% H2O2 . Phage plating efficiency was highest on the cultures at logarithmic phase and sometimes much influenced by host growth . Phage oUW 51 has a latent period of 2 h at 34 degrees C and a burst size between 35 and 40 . The latent period for phage oUW 21 is about 12 h, and the burst size is smaller than 30.

Biochim Biophys Acta, 1978 Jun 22, 519(1), 138 - 48
Saltatory thermal denaturation of double-stranded viral RNAs; Vizard DL et al.; The double-stranded RNAs from bacteriophage phi6 and the replicative form of mengovirus denature upon heating in a series of abrupt steps which resemble the subtransitions (thermalites) observed within the high resolution profiles of small, naturally occurring DNA molecules . Such RNA thermalites are approximately an order of magnitude narrower than typical thermal subtransitions of nominally single-stranded RNA . We conclude that the same features of nucleotide sequence that give rise to cooperative denaturation in DNA genomes are to be found also in RNA genomes . Thus, high resolution thermal denaturation profiles are useful for characterizing double-stranded RNA molecules as well as native DNA in the size range of common viruses . A medium containing dimethylsulfoxide was required to lower the Tm of the RNA samples to a satisfactory temperature range . For double-stranded RNA in 50% dimethylsulfoxide, the dependence of Tm on G . C composition was greater than that of DNA in the same medium and also greater than that of double-stranded RNA in an aqueous medium . The fact that RNA thermalites are broader than DNA thermalites and that the melting temperature of double-stranded RNA has a greater dependence on base composition than that of DNA, indicates that at least one of the thermodynamic parameters for double helix formation in RNA is different from that in DNA.

Biochim Biophys Acta, 1978 Jun 16, 510(1), 18 - 37
Association of the major coat protein of fd bacteriophage with phospholipid vesicles; Chamberlain BK et al.; The association of the major coat protein of fd bacteriophage with a phospholipid bilayer was investigated by analyzing the protein's susceptibility to proteolysis and its circular dichroism spectrum when incorporated into single-walled phospholipid vesicles . In the limits tested, this association appeared to be independent of the mass ratio of protein to lipid and of vesicle size, phospholipid composition, and method of preparation . The circular dichroism data are consistent with a similar "membrane-bound" conformation for all cases of vesicle-associated coat protein and for deoxycholate micelle-associated coat protein . Proteolysis of coat protein associated with deoxycholate micelles and with phospholipid vesicles defined the central hydrophobic core presumed to represent that portion of the protein which associates with membrane bilayers in vivo . The isolated core, which assumed a predominantly beta-type conformation in detergent solution, maintained a beta conformation when associated with a vesicle phospholipid bilayer.

In Vitro, 1978 Jun, 14(6), 543 - 9
The cytogenetic, proliferative and viability effects of four bacteriophages on human lymphocytes; Wenger SL et al.; Certain bacteriophages have been found in live virus vaccines, while a few others have been associated with disease states . Some of these phages have produced abnormal growth of eukaryotic tissue cultures . For this reason bacteriophages phiX-174, MS2, T2 and an isolate from live virus vaccines, phiV-1, were incubated with human cell cultures for examination of chromosomal effects, cell proliferation and viability . Mitogen-stimulated lymphocytes and human embryonic kidney tissue cultures showed no increase in chromosomal abnormalities for high doses of phage-infected versus control cultures . Tritiated-thymidine uptake, correlated with mitotic indices for phage-treated lymphocyte cultures, indicated a reduction in cell division, while 51-chromium release studies showed no cell death occurring in these cultures . This suggested that inhibition of DNA synthesis was occurring in some cells . The presence of phage in the supernate of cells that were exposed to phage suggested the possibility of phage attachment to the plasma membranes of lymphocytes, which may in turn affect the suppression of DNA synthesis.

Genetika, 1978 Jun, 14(6), 975 - 86
{Photosensitizing effect of 8-methoxypsoralen on bacteriophage cd}; Esipova VV et al.; Mutagenesis in extracellular phage sd by 8-metoxypsoralen (8-MOP) and longwave (lambda greater than 310 nm) UV-irradiation has been established . The kinetics of lethal and mutagenic effects of 8-MOP+light was studied . The efficiency of mutagenesis on the first linear part of mutation curve was 0.3% per the lethal hit which is 2 times lower than that of shortwave (lambda=254 nm) UV-irradiation . The maximum yield of mutants makes up 1%, after which the mutation curve is maintained . It has been established that the main (may be the only) contribution into mutagenesis is made by monoadducts, whereas the lethal effect is conditioned by diadducts (cross-links) . The comparison of the efficiency of mutagenic effects of 8-MOP+light with mutagenic effects of other kinds of irradiations was carried out . The possibility of repair of damaged 8-MOP+light phage sd DNA by transfection of Escherichia coli C (uvr+) and Cs (uvr-) lysozyme spheroplasts has been established . The repair mechanism of photodamage in intact phage sd induced with 8-MOP+light was also investigated using the method of two-step irradiation . It has been shown that 65% of photodamages are repaired in E . coli SK cells in the M9 medium, i . e . under cellular metabolism . The recovery of phage sd is completely inhibited in phosphate buffer . Unlike chloramphenicol (150 microgram/ml), 1% caffeine blocks the phage recovery only by 30% . The participation of phage sd determining enzymes in its intracellular recovery from 8-MOP+light damages is assumed.

Can J Biochem, 1978 Jun, 56(6), 508 - 16
The structure and maturation of intermediates in bacteriophage T7 DNA replication; Langman L et al.; Concatemeric DNA from T7-infected cells consists of phage genomes in a linear head-to-tail arrangement . Adjacent genomes within a concatemer overlap for the length of the terminal repetition . Fast-sedimenting T7 DNA contains single-stranded regions at roughly unit-lentth intervals but these interruptions are heterogeneously distributed and do not occur at the genetic termini . Mutations in either bacteriophage genes 9, 18, or 19 (required for DNA maturation and packaging) lead to the synthesis and persistence of DNA with fewer interruptions than normal.

Br J Cancer Suppl, 1978 Jun, 37(3), 64 - 7
Hypoxic cell radiosensitization by 8-methoxypsoralen; Redpath JL; 8-Methoxypsoralen has been shown to act as a radiosensitizer of hypoxic bacteriophage and bacteria . Radiosensitization of bacteriophage requires irradiation in the presence of excess scavenger . Bacterial radiosensitization requires deficiencies in uvr and rec genes . For the drug to be effective it must be present during irradiation . Pulse radiolysis studies have shown that, like electron-affinic radiosensitizers, 8MOP can efficiently oxidize free radicals . Unlike oxygen and most electron-affinic radiosensitizers 8MOP does not act in a purely dose-modifying fashion, and can radiosensitize beyond the oxygen effect.

Nucleic Acids Res, 1978 Jun, 5(6), 1833 - 44
The nucleotide sequence of threonine transfer RNA coded by bacteriophage T4; Guthrie C et al.; The nucleotide sequence of a low molecular weight RNA coded by bacteriophage T4 (and previously identified as species alpha) has been determined . The molecule is of particular biological interest for its associated biosynthetic properties . This RNA is 76 nucleotides in length, contains eight modified bases, and can be arranged in a cloverleaf configuration common to tRNAs . The anticodon sequence is UGU, which corresponds to the threonine-specific codons ACA G . The nucleotide sequence was determined primarily by nearest-neighbor analysis of RNA synthesized in vitro using {alpha-32P}nucleoside triphosphates . Using the single-strand specific nuclease S1, two in vivo labeled half-molecules were generated and analysed . This information together with restrictions imposed by nearest-neighbor data, provided a unique linear sequence of nucleotides with the features of secondary structure common to tRNA molecules.

Mol Gen Genet, 1978 Jun 1, 162(1), 101 - 7
Fine structure analysis of the threonine operon in Escherichia coli K-12; Saint-Girons I et al.; A fine structure analysis of the threonine operon in Escherichia coli K-12 was performed by deletion mapping . Lambda transducing bacteriophages carrying various parts of the threonine operon were isolated from strains in which the lacZ gene was fused to a thr gene . We tested for recombination between deletions of the threonine promotor extending into the threonine operon, carried by the phage, and bacterial thr auxotrophs . The relative order of thrO (operator) mutations was established . We propose that an operator region is located between a promoter region and the structural genes . Mutations leading to the desensitization of the aspartokinase I-homoserine dehydrogenase I towards threonine were localized in two different regions of the thrA gene.

J Virol, 1978 Jun, 26(3), 793 - 804
Effect of RNase III on efficiency of translation of bacteriophage T7 lysozyme mRNA; Hagen FS et al.; RNase III had no positive effect on the translation of bacteriophage T7 lysozyme mRNA in vivo or in vitro . The time of appearance and quanity of lysozyme in T7-infected E . coli BL107, an RNase III- strain, and T7-infected E . coli BL15, a nearly isogenic RNase III+ strain, were indistinguishable . Nearly identical patterns of lysozyme mRNA activity were obtained when RNA extracted at different times after infection of RNase III+ and RNase III- hosts was translated in cell-free extracts of E . coli containing or lacking RNase III . Exposure of RNA extracted from T7-infected E . coli BL107 (RNase III-) to purified RNase III did not increase the lysozyme mRNA activity of this RNA . The only result that implied that RNase III has a differential effect on the translatability of the lysozyme mRNA was the translation of fractionaed RNA from T7-infected E . coli BL107 . Translation of the smallest and largest lysozyme messages, 0.33 x 10(6) and 4 x 10(6) to 5 x 10(6) daltons, was the most inefficient in RNase III- cell-free extracts as compared to RNase III+ cell-free translation . The translation of the most abundant, medium-sized lysozyme mRNA between 0.9 x 10(6) and 1.5 x 10(6) daltons was the least affected by the absence of RNase III . The existence of a lag between the appearance of lysozyme mRNA and the appearance of lysozyme in T7 infection was confirmed . In these studies a very rapid method of RNA extraction was used, eliminating the possibility of continued RNA transcription during cell collection and RNA extraction . With this method of analysis, the length of the lag period was established at about 3 min . The possibility that RNase III is the controlling element of the lag period was eliminated by these investigations.

J Virol, 1978 Jun, 26(3), 783 - 92
Effect of RNase III on the size of bacteriophage T7 lysozyme mRNA; Hagen FS et al.; The size of lysozyme mRNA from T7-infected E . coli RNase III+ and RNase III- strains was analyzed by sucrose gradient sedimentation, dimethylsulfoxide (Me2SO) sucorse gradient sedimentation, and preparative gel electrophoresis . Each technique revealed a similar size distribution of multiple lysozyme mRNA's . Analysis by preparative gel electrophoresis of RNA extracted after infection of Escherichia coli Bst (RNase III+) separated lysozyme mRNA into six peaks of activity ranging in size from 0.2 x 10(6) to 1.9 x 10(6) daltons . Four well-resolved major peaks of activity were detected, having apparent molecular weights of approximately 0.61 x 10(6), 0.76 x 10(6), 0.92 x 10(6), and 1.3 x 10(6) . A broad band of activity, with a molecular weight range from 0.2 x 10(6) to 0.37 x 10(6), was also present, and a sixth peak of activity was sometimes observed that migrates with a mobility corresponding to a molecular weight of 1.9 x 10(6) . Judging from their molecular weight as estimated by electrophoresis, most, if not all, of the lysozyme mRNA's were polycistronic . The RNA extracted after infection of an RNase III- host contained a more heterogeneous collection of lysozyme mRNA's . In addition to lysozyme mRNA activity on RNAs with molecular weights between 0.2 x 10(6) and 1.9 x 10(6), RNA species with molecular weights estimated at 4 x 10(6) to 5 x 10(6) were also detected . The data indicate that RNase III processes at least some of the primary lysozyme transcripts . The multiple lysozyme mRNA's represent discrete RNA species rather than aggregates because analysis of the size of lysozyme mRNA under completely denaturing conditions, in Me2SO, produced a similar size distribution of lysozyme mRNAs . Also, treatment of RNA with 90% Me2SO, which separates the strands of a completely double-stranded RNA, did not significantly alter the electrophoretic mobility of the lysozyme mRNA.

J Virol, 1978 Jun, 26(3), 595 - 602
Correlation between UV dose requirement for lambda bacteriophage induction and lambda repressor concentration; Baluch J et al.; Escherichia coli K-12 wild type and a uvrA mutant derivative were used to construct isogenic strains bearing one, two, three, or more phage lambda cI genomes and containing increasing concentration of lambda repressor as measured by in vitro operator DNA-binding assays . The survival and phage induction in response to UV irradiation were determined . In both strains, dose-response relationships were obtained as a function of the cellular repressor concentration . The uvrA lysogens required one-tenth the UV fluence of the wild-type counterparts for induction . Lysogenic strains containing plasmids that overproduce the lambdaind+ repressor and the same lysogens with plasmids overproducing the lambdaind- repressor displayed the same survival curves as the nonlysogenic parental strain; however, only the former produced infectious centers (at a frequency of 2 x 10(-3) to 5 x 10(-4) in response to radiation.

J Biochem (Tokyo), 1978 Jun, 83(6), 1763 - 7
Synthesis of bacteriophage phiC DNA in dna mutants of Esherichia coli; Kodaira KI et al.; Host dna functions involved in the replication of microvirid phage phiC DNA were investigated in vivo . Although growth of this phage was markedly inhibited even at 35-37 degrees C even in dna+ host, conversion of the infecting single-stranded DNA into the double-stranded parental replicative form (stage I synthesis) occurred normally at 43 degrees C in dna+, dnaA, dnaB, dnaC(D), and dnaE cells . In dnaG mutant, the stage I synthesis was severely inhibited at 43 degrees C but not at 30 degrees C . The stage I replication of phiC DNA was clearly thermosensitive in dnaZ cells incubated in nutrient broth . In Tris-casamino acids-glucose medium, however, the dnaZ mutant sufficiently supported synthesis of the parental replicative form . At 43 degrees C, synthesis of the progeny replicative form DNA (stage II replication) was significantly inhibited even in dna+ cells and was nearly completely blocked in dnaB or dnaC(D) mutant . At 37 degrees C, the stage II replication proceeded normally in dna+ bacteria.

J Bacteriol, 1978 Jun, 134(3), 854 - 60
Isolation and characterization of motile Escherichia coli mutants resistant to bacteriophage chi; Icho T et al.; Four mutants of Escherichia coli that are resistant to the flagellotropic phage chi, but are motile, were isolated . When they were observed in liquid culture bylight microscopy, one mutant exhibited circular movement and another tumbled at high frequency on the surface of a glass slide . The remaining two mutants moved normally . None of these mutants adsorbed the wild-type strain of chi . P1 transduction revealed that the mutation sites of these four mutants were more than 97% contransducible with a site in hag, the structural gene for flagellin . When flagellins of these mutants were chromatographed on a diethylaminoethyl-cellulose column, two eluted slower and one eluted slightly faster than the flagellin of the parental strain . The other flagellin eluted at the same position as that of the parent . Host range mutants of phage chi, which could infect these bacterial mutants, were isolated.

Proc Natl Acad Sci U S A, 1978 Jun, 75(6), 2679 - 83
Inverted repeated DNA from Chinese hamster ovary cells studied with cloned DNA fragments; Jelinek WR; Fragments from the DNA of Chinese hamster ovary cells produced by restriction endonuclease EcoRI were cloned in Charon 16A lambda bacteriophage and examined for the ability to hybridize in situ with 32P-labeled double-stranded regions from heterogeneous nuclear RNA (hnRNA) . Of 235 clones tested, 87 (37%) contained sequences that hybridized with the double-stranded hnRNA . Nine of these were examined for the presence of inverted repeat DNA structures (ir-DNA) by electron microscopy . All nine contained at least two elements of ir-DNA . Analysis of heteroduplexes formed from the DNAs of the different clones as well as T1 fingerprint analysis of the double-stranded hnRNA hybridized to each of the nine clones suggest that there is detectable nucleotide sequence homology in the various ir-DNAs . There are ca 3 X 10(5) ir-DNA pairs in the haploid Chinese hamster ovary cell genome.

Biochem J, 1978 Jun 1, 171(3), 725 - 32
Substrate, metal and template effects on inhibition of bacteriophage-qbeta ribonucleic acid polymerase by ortho- and pyro-phosphate; Brooks RR et al.; Two reactions of bacteriophage-Qbeta RNA polymerase with synthetic templates were characterized and used to study the effects of substrate, metal and template on inhibition by Pi and PPi . Analysis of the poly(C)-dependent reaction yielded results on kinetics, GTP-dependence, preference for Mn2+ over Mg2+, and Michaelis constants for template similar to those in the literature . New data are provided for the poly(U2,C)-dependent reaction . Our results suggest that GTP and Mn2+ can form relatively stable complexes with the polymerase and that such complexes change the interaction of the enzyme with the inhibitors, Pi and PPi.

Tubercle, 1978 Jun, 59(2), 143 - 6
Differentiation of BCG from other variants of Mycobacterium tuberculosis isolated from clinical material; Yates MD et al.; BCG isolated from clinical material may be reliably differentiated from other variants within the species Mycobacterium tuberculosis by means of a few simple cultural and biochemical tests and by bacteriophage typing . Animal pathogenicity tests may therefore be avoided.

Mol Gen Genet, 1978 May 31, 161(3), 245 - 50
The recognition of mismatched base pairs in DNA by DNase I from Ustilago maydis; Pukkila PJ; The activity of Ustilago maydis DNase I, an enzyme implicated in genetic recombination, on DNA substrates containing unpaired or mismatched bases, was examined . The enzyme nicked supercoiled PM-2 molecules, converting these to relaxed circular and linear molecules . Discrete double stranded linear fragments smaller than unit length were also observed after digestion at high enzyme concentration . Heteroduplex molecules were constructed using phi80 bacteriophage derivatives which contained single base substitutions within the E . coli tRNA1tyr gene . Single and double stranded nicking at or near the single mismatched site was observed with three out of the five pairs of heteroduplexes.

Biochemistry, 1978 May 30, 17(11), 2064 - 9
Selectivity of RNA chain initiation in vitro . 3 . Variables affecting initiation of transcription; Miller JS et al.; The effects of salt, temperature, enzyme to DNA ratio, and heparin challenge on both total RNA synthesis and synthesis from specific promoters are examined using DNA from bacteriophages lambdacb2 and T7 . Determination of synthesis from specific promoters is carried out by the fractionation and quantitation on polyethylenimine-cellulose thin-layer chromatograms of the 5'-terminal oligonucleotides produced by digestion of the RNA products with T1 RNase . The major findings of this work are that (1) lambdacb2 promoters are more salt sensitive than T7 promoters and the salt concentration affects individual promoters differently, (2) T7 promoters initiate maximally at 37 degrees C but the transition temperatures of promoters vary and may be dependent on the salt concentration, (3) increasing the enzyme to DNA ratio results in increasing initiations at the promoters on T7 DNA without causing measurable initiation at non-promoters, and (4) T7 and lambdacb2 promoters show differences in stability when challenged with heparin.

Biochemistry, 1978 May 30, 17(11), 2059 - 64
Selectivity of RNA chain initiation in vitro . 2 . Correlation of 5'-triphosphate-labeled oligonucleotides on polyethyleniminecellulose thin-layer chromatography with RNA transcripts of bacteriophage lambda cb2 and T7; Miller JS et al.; Methods are described for the correlation of 5'-terminal oligonucleotides separated by two-dimensional polyethyleniminecellulose thin-layer chromatogrphy with specific RNA transcripts made in vitro from DNA of phages T7 and lambdacb2 . The 5'-terminal oligonucleotides transcribed from DNA containing mutations and alterations which affect the RNA transcripts from specific promoters were compared with fingerprints of RNA from wild type DNA . Specific RNAs were purified on polyacrylamide gels and digested and their 5'-terminal oligonucleotides subjected to chromatography . Transcription of DNA fragments containing specific promoters was carried out and the 5'-oligonucleotide fingerprints of the RNA products compared with fingerprints of the RNA from the whole DNA . Using these methods and information known about T7 and lambdacb2 RNA 5'-terminal sequences, it was possible to identify many of the oligonucleotides separated on the polyethyleniminecellulose chromatography system.

J Biol Chem, 1978 May 25, 253(10), 3671 - 6
Escherichia coli mutants completely deficient in adenosylmethionine decarboxylase and in spermidine biosynthesis; Tabor CW et al.; Mutants of Escherichia coli deficient in adenosylmethionine decarboxylase, an enzyme in the biosynthetic pathway for spermidine, were isolated after mutagenesis of E . coli K 12 with N-methyl-N-nitro-N-nitrosoguanidine or with the bacteriophage Mu . The mutated gene, designated speD, is at 2.7 min on the E . coli chromosome map . In several of the mutants resulting from Mu insertion both adenosylmethionine decarboxylase activity and spermidine were undetectable . The absence of spermidine from speD strains proves the essential role of adenosylmethionine decarboxylase in the biosynthetic pathway for spermidine . Despite the complete absence of spermidine, these mutants grew at 75% of the wild type rate.

Biochim Biophys Acta, 1978 May 3, 540(2), 313 - 9
Folate polyglutamates in T4D bacteriophage and T4D-infected Escherichia coli; Nakamura K et al.; The folate compound which is a structural component of the Escherichia coli T-even bacteriophage baseplates, has been identified as the hexaglutamyl form of folic acid using a new chromatographic procedure (Baugh, C.M., Braverman, E . and Nair, M.G . (1974) Biochemistry 13, 4952-4957) . It has also been found that the host cell contains a variety of polyglutamyl forms of folic acid . The major form is the triglutamate (about 50%) but small amounts of higher molecular weight folates including the octaglutamate (1.8%) have been identified . Upon infection with wild-type T4D bacteriophage there is a shift in the distribution of the folate compounds so that the folyl polyglutamyl compounds having the higher molecular weights are increased . Infection of E . coli with baseplate mutants of T4D containing an amber mutation in gene 28 resulted in the formation of significant amounts (over 7%) of folate compound(s) of molecular weight much higher than those observed either in uninfected cells or cells infected with wild-type T4D . It is suggested that the T4D gene 28 product functions to cleave glutamate residues from high molecular weight folyl polyglutamates to increase the availability of the folyl hexaglutamate for virus assembly.

Natl Cancer Inst Monogr, 1978 May, (48), 7 - 8
Use of an EK-2 vector for the cloning of DNA from higher organisms; Leder P et al.; A certified EK2 bacteriophage lambda vector, which is useful for cloning fragments of DNA from higher organisms, is described.

J Virol, 1978 May, 26(2), 429 - 34
178-Nucleotide sequence surrounding the cos site of bacteriophage lambda DNA; Nichols BP et al.; A nucleotide sequence of 61 nucleotides at the left end and 117 nucleotides at the right end of DNA from bacteriophage lambdacI857Sam7 was determined by the Maxam and Gilbert method . A perfect inverted repeat sequence of 10 nucleotides is near the left end, and one of 15 nucleotides is near the right end . DNA from another closely related lambda strain, lambdacI857prm116Sam7, has about 10% divergence in the sequence of the first 110 nucleotides at the right end and has a 17-member perfect inverted repeat sequence.

Mol Biol (Mosk), 1978 May-Jun, 12(3), 505 - 14
{Complex of single-stranded phage DNA and protein--a product of bacteriophage fl gene 3 . Distribution of gene 3 protein in the DNA molecule}; Zlochevskii ML et al.; Upon a 50% isopropanol treatment of phage fl in a 1 M NaCl solution protein A (gene 3 product)--DNA complex is precipitated while protein B (gene 8 product) was still solubilized . After such a treatment the DNA--protein complex containing 10--40% of protein A and less than 0.0025% of protein B was obtained . Evidence was obtained that there was no non-specific rearrangement of protein A during the isolation procedure . The complex was treated with endonuclease R.HAC III, followed by electrophoresis of the resulted fragments and estimation of the {14C} protein A (labeled with {14C}histidine) throughout the gel . The maximal radioactivity coincided with the DNA bands, being proportional to the DNA content in the respective bands . The data obtained indicate that protein A is iniformly arranged along the DNA molecule.

J Virol, 1978 May, 26(2), 420 - 8
Head maturation pathway of bacteriophages T4 and T2 . IV . In vitro transformation of T4 head-related particles produced by mutants in gene 17 to capsid-like structures; Carrascosa JL; T4 mutants in gene 17 accumulate particles which contain the main head protein in the cleaved form (gp23*) arranged in an unexpanded lattice (empty small particles), together with other expanded capsids (empty large particles) . The isolated empty small particles can be transformed in vitro, by lowering the ionic strength, to capsid-like structures . This structural transformaton is not coupled to chemical modification of the structural proteins of the empty small particles . In contrast to unexpanded particles that are easily dissociated, the transformed structures are as resistant to dissociation as other T-even head-related particles with expanded lattice . Furthermore, the transformed particles are able to bind in vitro hoc and soc proteins, rendering capsids indistinguishable from the normal T4 capsids both morphologically and by their stability against denaturing agents . Our results indicate that the in vitro transformation of the empty small particles might mimic important and characteristic aspects of the in vivo maturation of T4 heads, thus suggesting a possible role of the "cleaved but unexpanded" particle in the maturation pathway of the T4 shell.

J Virol, 1978 May, 26(2), 265 - 71
UV-induced mutation in bacteriophage T4; Yarosh DB; Two late gene am mutants of bacteriophage T4 that can be induced to revert by UV were crossed to a temperature-sensitive ligase mutant . In the double mutants, UV-induced reversion was eliminated at a semirestrictive temperature . When the single am mutants were irradiated and then allowed a single passage in a permissive host, the UV-induced reversion frequency was increased by 15- to 25-fold . This increased mutagenesis was also abolished by the presence of the ligase allele . When the UV-irradiated single am mutants multiply infected a permissive host, allowing multiplicity reactivation to occur, the induced reversion frequency was reduced similarly to the reduction in lethality . The mutagenesis that remained was again abolished by the presence of the ligase allele . It is concluded that UV induces mutations in phage T4 through the action of a pathway that includes polynucleotide ligase . The increase in mutation frequency after growth in a permissive host implies that mutagenesis can occur at more than one stage of the infection rather than only in an early stage before expression of the mutant genome . The process of multiplicity reactivation appears to be error-free since it overcomes lethal lesions without inducing new mutations.

Proc Natl Acad Sci U S A, 1978 May, 75(5), 2266 - 70
Nucleotide sequence of the recognition site for the restriction-modification enzyme of Escherichia coli B; Ravetch JV et al.; The nucleotide sequence of the recognition site for the restriction-modification enzyme of Escherichia coli B (SB site) has been determined . The recognition site is a 15-nucleotide sequence consisting of the trimer 5'TGA3', followed by an 8-nucleotide domain of variable sequence, which in turn is followed by tetramer 5'TGCT3' . The sequence has no 2-fold rotational symmetry . Single base changes in the constant nucleotide domains result in the loss of sensitivity to both restriction and modification . Our data are also consistent with modification occurring by methylation of two adenine residues per SB site: one on the adenine of the trimer 5'TGA3' and the other on the complementary strand on the adenine complementary to the first thymine of the tetramer 5'TGCT3' . All nine independently isolated spontaneous mutants at the SB1 site of bacteriophage f1 are caused by a G-to-T transversion . Mutations at the SB2 site are caused by various single base changes.

In Vitro, 1978 May, 14(5), 413 - 7
A comparison of methods for detecting bacteriophage contamination of tissue culture sera; Mayo JA; Detection of bacteriophage contamination of tissue culture sera by direct plating has been compared with detection methods based on batch enrichment and on the Poisson distribution (PD plating) . Batch enrichment is extremely sensitive for detecting the presence of phage contamination . PD plating combines sensitivity with isolation of each contaminating phage in pure culture . Both batch enrichment and PD plating are more sensitive than direct plating . Neither method requires highly trained personnel or specialized equipment.

Nucleic Acids Res, 1978 May, 5(5), 1689 - 700
A cell-free system for the replication fo bacteriophage M-13 duplex DNA; Schneck PK et al.; Cell-free extracts from M-13 am5 infected Escherichia coli cells which are highly concentrated on cellophane membrane disks replicate efficiently endogenous M-13 duplex DNA . If the reaction is carried out in the presence of bromodeoxyuridine triphosphate, the majority of the label is found in two classes of hybrid DNA molecules in which either the viral or the complementary strand is newly synthesized . A minor portion of the label is incorporated into fully synthetic duplex DNA . DNA synthesis requires ATP and is inhibited by nalidixic acid, novobiocin, and arabinosylnucleoside triphosphates . Rifampicin blocks preferentially the synthesis of molecules with labeled complementary strands . A similar effect is observed upon addition of the helix-destabilising M-13 gene V protein . In contrast, addition of E . coli helix-destabilising protein (Eco HD-protein) stimulates the synthesis of both types of hybrid DNA molecules as well as the formation of fully synthetic duplex DNA.

J Bacteriol, 1978 May, 134(2), 655 - 67
Genes for the hook-basal body proteins of the flagellar apparatus in Escherichia coli; Komeda Y et al.; Of the more than 30 genes required for flagellar function, 6 are located between pyrC and ptsG on the Escherichia coli genetic man . This cluster of genes is called flagellar region I . Four-point transductional crosses were used to establish the position and order of the region I flagellar genes with respect to the outside markers ptsG and pyrC . Bacteriophage lambda-E . coli hybrids that contained most of the genes necessary for flagellar formation were constructed . The properties of specific hybrids that carried the region I fla genes were examined by genetic complementation and by measuring the capacity of the hybrids to direct the synthesis of specific polypeptides . The results of these tests with lambda hybrids and with a series of deletion mutations derived from the lambda hybrids demonstrated the existence of at least six flagellar-specific cistrons . These directed the synthesis of polypeptides with the following apparent molecular weights: flaV, 11,000; flaK, 42,000; flaL, 30,000 and 27,000; flaM, 38,000; flS, 60,000; and flaT, 35,000 . Plasmid ColE1-E . coli hybrids with region I flagellar genes were also used to program the synthesis of polypeptides in minicell-producing strains . The polypeptides synthesized in these experiments were identical to polypeptides of the hook-basal body structure and helped to confirm the assignment of genes to specific polypeptides . The synthesis of all of these polypeptides was regulated by the same mechanism that regulates the synthesis of other flagellar-related structural components.

Int J Radiat Biol Relat Stud Phys Chem Med, 1978 May, 33(5), 425 - 41
Quantitative determination of cross-linkage of bacteriophage DNA and protein by ionizing radiation; Hawkins RB; Coliphage T7 was dissolved in tryptone broth and exposted to 60C gamma-radiation . Cross-linkage of DNA and protein of the virion was assayed using phenol-water countercurrent distribution . The results are interpreted in terms of a statistical model of cross-linkage and double-strand breaks . It was found that protein--DNA cross-links accumulate linearly with dose at a rate of o.74 X 10(-11) cross-links per rad per nucleotide pair, which is of the order of 5 per cent of the formation rate of double-strand breaks.

Proc Natl Acad Sci U S A, 1978 May, 75(5), 2276 - 80
Genetic recombination and complementation between bacteriophage T7 and cloned fragments of T7 DNA; Campbell JL et al.; Frafments of phage T7 DNA have been cloned in Escherichia coli by using the plasmid pMB9 . Such cloned fragments are able to recombine with infecting phages, thus providing a means to integrate the physical and genetic maps of T7 DNA . Approximately 65% of the T7 DNA molecule has been found in clones so far, and analysis of these clones has mapped genes 12-17 with an accuracy of about 1% the total length of T7 DNA . At least some cloned segments can supply T7 functions to infecting phages.

Proc Natl Acad Sci U S A, 1978 May, 75(5), 2200 - 4
Construction of a novel plasmid-phage hybrid: use of the hybrid to demonstrate ColE1 DNA replication in vivo in the absence of a ColE1-specified protein; Kahn M et al.; A hybrid bacteriophage, P420, was constructed in vitro; it contains part of bacteriophage P4 and a 3.6-kilobase derivative of plasmid ColE1 . In Escherichia coli, the plasmid-phage hybrid can exist as a stable plasmid or can be packaged into infective bacteriophage particles . Replication of P420, directed by the ColE1 replicon, was found to occur after P420 phage infection of E . coli cells that had been incubated in the presence of chloramphenicol . Replication began without a lag period and resulted in the synthesis of covalently closed circles of P420 DNA . Like ColE1 DNA replication but unlike that of P4, replication was dependent on DNA polymerase I and was sensitive to rifampicin . The presence of a resident ColE1 plasmid in the infected cells resulted in an inhibition of the replication of the incoming P420 DNA . These results indicate that ColE1 does not require a plasmid-coded protein to replicate its DNA in vivo and demonstrate the utility of P4 bacteriophage for coupling bacteriophage properties to a plasmid replicon.

Proc Natl Acad Sci U S A, 1978 May, 75(5), 2180 - 4
A general method to assess similarity of protein structures, with applications to T4 bacteriophage lysozyme; Remington SJ et al.; A method is proposed that permits the structural similarity between any pair of proteins to be analyzed in a completely general manner . In the proposed procedure, all possible structural segments of a given length from one protein are compared with all possible segments from the other protein . This set of comparisons reveals any structural similarities between the two proteins being compared, and also provides a basis for estimating the probability that a particular degree of structural homology could have occurred by chance . Application of the method to the comparison of T4 bacteriophage lysozyme and carp calcium-binding protein suggests that the previously reported structural similarity between parts of these two proteins {Tufty, R . M.& Kretsinger, R . H . (1975) Science 187, 167-169} is no better than would be expected by chance . On the other hand, the structural correspondence between phage lysozyme and hen egg-white lysozyme {Rossman, M.G . & Argos, P . (1976) J . Mol . Biol . 105, 75-96} does appear to be significant.

J Gen Virol, 1978 May, 39(2), 377 - 80
Chromic-acid formaldehyde fixation of nucleic acids of bacteriophage phi6 and infectious bovine rhinotracheitis virus; Langenberg WG et al.; Bacteriophage phi6 nucleic acid was present as a torus after chromic acid-formaldehyde-OSO4 fixation and acetone and propylene oxide dehydration . A herpes virus, infectious bovine rhinotracheitis virus, had its DNA mostly as a torus, collapsed in the centre, or as a network, after glutaraldehyde-OSO4 fixation, but in an uncollapsed torus or network formation after chromic acid-formaldehyde-OSO4 . This fixative stabilized nucleic acids, allowing acetone dehydration and plastic embedding without collapse of nucleic acid to the centre of the virion.

J Clin Microbiol, 1978 May, 7(5), 467 - 9
Modification of methods used in bacteriophage typing of Mycobacterium tuberculosis isolates; Jones WD Jr et al.; A procedure in which soft agar overlays were used in bacteriophage-typing Mycobacterium tuberculosis is presented . This safer method uses commercially available media, whereas media presently used must be prepared in the laboratory . Single plaque isolations of the phage BG-1 specifying phage type A and B of M . tuberculosis were readily made by using the modified procedures . This purification and the use of prototype strain Myc 1415 as the indicator host strain have significantly enhanced the ability to discriminate among strains of phage types A and B.

Biochim Biophys Acta, 1978 Apr 27, 518(2), 216 - 32
A spectroscopic and electron microscopic examination of the highly condensed DNA structures formed by denaturation in Mg(ClO4)2; Ott GS et al.; 1 . Thermal denaturation in 1.5 M Mg(ClO4)2 of the DNA from bacteriophage lambda results in four well-separated subtransitions, as monitored by the accompanying increase in absorbance . The midpoint of the hyperchromic spectrum is significantly lowered compared to either 1.5 M MgCl2 or 3.0 M NaClO4 . 2 . The first two subtransitions are associated with the melting of the A . T-richest regions of the lambda DNA, as revealed by electron micrographs following fixation with formaldehyde . 3 . Commencing with the third subtransition, an unusual DNA structure is observed in electron micrographs . In this structure the A . T-rich half of the molecule appears completely condensed, whereas the G . C-rich half remains native . 4 . During the fourth subtransition DNA molecules condense completely and eventually aggregate to form extremely high molecular weight particles containing centers of electron density . Tendrils of DNA, primarily duplex, radiate outward from these centers . 5 . The aggregation may be reversed by the removal of magnesium . The intramolecular condensation may be at least partly reversed by increasing the Mg(ClO4)2 concentrations to saturating levels.

Mol Gen Genet, 1978 Apr 25, 161(1), 1 - 8
E . coli K-12 pel mutants, which block phage lambda DNA injection, coincide with ptsM, which determines a component of a sugar transport system; Elliott J et al.; Escherichia coli pel- mutants inhibit the penetration of bacteriophage lambda DNA into the cell . Using P1 mediated cotransduction, we mapped pel- mutations between markers fadD and eda in the interval of minute 40 of the revised E . coli K-12 map . This places pel in the same region as genes kdgR and ptsM . Mutations in kdgR usually do not alter the Pel phenotype, and vice versa . In contrast, about 30% of ptsM- mutants are also pel-, and all pel- mutants isolated are ptsM- . These results suggest that pel and ptsM are one and the same gene . This interpretation would identify the bacterial product required for injection of phage lambda DNA as a component of the phosphoenolpyruvate-dependent phosphotransferase system specific for mannose, glucosamine, glucose and fructose . However, the experimental results do not exclude an alternative explanation: that pel and ptsM identify two closely linked genes which would be simultaneously affected at high frequency by a particular mutational event.

J Biol Chem, 1978 Apr 10, 253(7), 2463 - 70
Structural changes in the T4 gene 32 protein induced by DNA polynucleotides; Williams KR et al.; Alterations in the structure of the DNA-binding protein specified by gene 32 of bacteriophage T4 have been detected using partial trypsin digestion as a conformational probe . Limited tryptic hydrolysis of the gene 32 protein removes a fragment ("B" region), of 21 amino acids from the NH2 terminus and a 6,200-dalton fragment ("A" region) from the COOH terminus . Poly(dT), poly(dC), and single-stranded DNA increase the rate of tryptic hydrolysis of the "A" region but decrease the rate of tryptic hydrolysis of the "B" region . Oligonucleotides, which are too short to permit cooperative binding of the gene 32 protein, do not alter the rate of tryptic hydrolysis of either the "A" or "B" regions . A model which accounts for these findings requires that the "B" region be involved in gene 32 protein:gene 32 protein interactions when the gene 32 protein: DNA complex is formed . As a consequence of the gene 32 protein:DNA interaction, the "A" region should be able to participate more effectively in vivo and in vitro with other proteins involved in T4 DNA metabolism.

J Biol Chem, 1978 Apr 10, 253(7), 2132 - 9
Purification and properties of the bacteriophage T4 gene 31 protein required for prehead assembly; Castillo CJ et al.; A low molecular weight (approximately 16,000), early protein is characterized as the product of the essential T4 head assembly gene 31 . This gene is known to be required to allow formation of any ordered head structure from the major T4 capsid protein, P23 (Laemmli, U.K., Beguin, F., and Gujer-Kellenberger, G . (1970) J . Mol . Biol . 47, 69-85) . In wild type infection P31 synthesis ceases at late times; in contrast, P31 is overproduced in certain early or regulatory T4 mutant infections, particularly gene 55 mutant infections . P31 was purified preparatively from Escherichia coli infected with the latter mutant, but could only be obtained for the most part in modified form, possibly due to unusual sensitivity to a proteolytic activity . P31 is not cleaved in vivo during normal head assembly, nor does it become a part of the mature head or any ordered prehead structure as determined by an immunological assay using antiserum prepared against the purified protein . However P31 does appear to become a part of the unordered P23 aggregates (lumps) which accumulate when ordered P23 assembly is prevented . We cound find no evidence for P31 association with T4 DNA or the host membrane . Our experiments favor the hypothesis that P31 directly affects the aggregation state and solubility properties of P23.

Biochemistry, 1978 Apr 4, 17(7), 1239 - 46
Conformational states of a hydrophobic protein . The coat protein of fd bacteriophage; Nozaki Y et al.; The coat protein of fd bacteriophage has a short polypeptide chain of only 50 amino acid residues, containing a highly hydrophobic segment of 19 amino acids that is entirely devoid of ionic or other strongly polar amino acids . In the viral particle the protein exists as a closely packed array of alpha helices . It can be transformed to a monomeric randomly coiled polypeptide in very concentrated (greater than or equal to 7.3 M) guanidinium chloride . In anionic detergents or phospholipids the protein is dimeric, with a mixed conformation ("50% alpha"), the hydrophobic segment having a beta structure, whereas the two ends are predominantly alpha helical . In guanidinium chloride at concentrations of 6 M or less, and under other conditions in the absence of an anionic detergent or phospholipid, the protein forms an intractable polymer, with a beta-type conformation . If the protein is succinylated an oligomeric form of this structure (speculatively thought to be a soluble variety of a "beta barrel") can be obtained as a metastable state . The 50% alpha conformation, the beta oligomer, and the random coil can be interconverted reversibly, but formation of the beta polymer appears to be irreversible.

Biochemistry, 1978 Apr 4, 17(7), 1166 - 70
Use of ethidium bromide fluorescence enhancement to detect duplex DNA and DNA bacteriophages during zone sedimentation in sucrose gradients: molecular weight of DNA as a function of sedimentation rate; Serwer P et al.; Duplex DNA molecules and DNA bacteriophages have been sedimented through 5--25% sucrose gradients containing ethidium bromide . The location of DNA within the gradients has been determined by illuminating gradients with ultraviolet light and observing the ethidium bromide fluorescence enhancement induced by the DNA . The relative sedimentation rates of linear, duplex DNAs from bacteriophages T4, T5, T7 and an 8.3% T7 deletion mutant have been determined . The distances sedimented by DNA have been corrected, when necessary, for a progressive decrease in sedimentation rate that occurs after the DNA has traversed 40% of the sucrose gradient . The corrected distances sedimented by two DNA molecules, r1' and r2', are related to the DNA molecular weights, m1 and m2, by the equation: r1'/r2' = (m1/m2)0.38 when 0.025--0.70 microgram of each type of DNA is sedimented . Intact bacteriophages were also sedimented in ethidium bromide--sucrose gradients and detected by fluorescence enhancement.

Infect Immun, 1978 Apr, 20(1), 303 - 6
Isolation of a bacteriophage for actinomyces viscosus; Delisle AL et al.; A lytic phage which produces clear plaques on a human isolate of Actinomyces viscosus was isolated from a sample of raw domestic sewage.

J Biochem (Tokyo), 1978 Apr, 83(4), 971 - 6
Replication of G4 progeny double-stranded DNA in dna mutants of Escherichia coli; Kodaira K et al.; Host functions required for replication of progeny double-stranded DNA of bacteriophage G4 were examined by using metabolic inhibitors and Escherichia coli dna mutants . In dna+ bacteria, synthesis of the progeny replicative form (RF) was relatively resistant to 30 microgram/ml of chloramphenicol, but considerably sensitive to 200 microgram/ml of rifampicin . The RF replication was severely inhibited by 50 microgram/ml of mitomycin C, 50 microgram/ml of nalidixic acid, or 200 microgram/ml of novobiocin . At 41 degrees C, synthesis of G4 progeny RF was distinctly affected in a dnaC(D) mutant and in a dnaG host . The progeny RF replication was prevented at 42 degrees C in a dnaE strain as well as in a dnaB mutant . In a dnaZ strain, the synthetic rate of the progeny RF was markedly reduced at 42 degrees C . At 43 degrees C, the rate of G4 progeny RF synthesis was reduced even in dna+ or dnaA bacteria, but significant amounts of the progeny RF were still synthesized in these hosts at the high temperature . In addition to five dna gene products, host rep function was essential for the RF replication.

Genetika, 1978 Apr, 14(4), 695 - 703
{Transmission of bacteriophage T4 amber mutants . I . Temperature sensitivity of gene 26 T4 phage mutant amN131 multiplication in Escherichia coli B cells}; Nivinskas RG et al.; When studying the single cycle of the multiplication of gene 26 mutant amN131 of phage T4, like in temperature shift experiments, the yield of this mutant in non-permissive host depends greatly on the temperature . The burts size of phage in Escherichia coli B is found to be 3.3 phage particles at 25 degrees C, 1.6 at 30 degrees C, 0.051 at 37 degrees C and 0.0007 at 41 degrees C . In the case of permissive host (E . coli CR-63) the burst size per cell decreases from 158 to 49 phage particles at the same temperature interval . The results of the single-burst experiments indicate, that when the incubation temperature increases, the number of E . coli B cells, in which the phage particles maturate, also decreases . It results in the dependence of the transmission coefficient value on the temperature . The transmission coefficient in the conditions favourable for the maturation of the phage is found to be 0.80 . It is shown by several methods that the temperature sensitivity of the multiplication of the mutant amN131 in bacterial cells is entirely due to amber mutation in genome of the phage . Therefore the amber mutants having high temperature sensitivity when maturating in non-permissive host cells exist among ordinary amber mutants of phage T4.

J Bacteriol, 1978 Apr, 134(1), 92 - 9
Synthesis and activities of branched-chain aminoacyl-tRNA synthetases in threonine deaminase mutants of Escherichia coli; Williams AL et al.; Valyl-, isoleucyl-, and leucyl-tRNA synthetase activities were examined in an Escherichia coli K-12 strain that possessed a deletion of three genes of the ilv gene cluster, ilvD, A, and C, and in a strain with the same deletion that also carried the lambdadilvCB bacteriophage . It was observed that the branched-chain tRNA synthetase activities of both strains were considerably less than those of the normal strain during growth in unrestricted medium . Furthermore, during an isoleucine limitation, there was a further reduction in isoleucyl-tRNA synthetase activity and an absence of the isoleucine-mediated derepression of valyl-tRNA synthetase formation in both of these mutants, as compared with the normal strain . In addition, it was observed that these branched-chain synthetase activities were reduced in steady-state cultures of several ilvA point mutants . However, upon the introduction of the ilv operon to these ilvA mutants by use of lambda bacteriophage, there was a specific increase in the branched-chain synthetase activities to levels comparable to those of the normal strain . These results support our previous findings that the stability and repression control of synthesis of these synthetases require some product(s) missing in the ilvDAC deletion strain and strongly suggest this component is some form of the ilvA gene product, threonine deaminase.

Proc Natl Acad Sci U S A, 1978 Apr, 75(4), 1652 - 6
Site-specific initiation of a DNA fragment; Hourcade D et al.; The first step in the replication cycle of the single-stranded DNA phages is the conversion of the infecting positive strand circle to a duplex ring . This event involves the de novo initiation of a negative strand, using the infecting positive strand cycle as a template . The synthesis of the negative strand is in many respects analogous to the formation of a fragment during cellular DNA replication . In this paper we describe the initiation of the negative strand of bacteriophage G4 . The data establish that, in vivo, the synthesis of the G4 negative strand is initiated at a specific site, which we have mapped on the 5400-base viral chromosome.

Proc Natl Acad Sci U S A, 1978 Apr, 75(4), 1783 - 7
Mechanism of action of the cro protein of bacteriophage lambda; Johnson A et al.; The mechanism of action of cro protein was probed by measuring its ability to protect DNA against methylation by dimethyl sulfate and its effect on transcription in vitro . The cro protein binds to the same three sites in the right operator (OR) of bacteriophage lambda DNA as does the lambda repressor . Dimethyl sulfate protection experiments reveal major groove contacts for both proteins, and cro protein protects from methylation a subset of those purines protected by lambda repressor . These experiments also show that the relative affinity of these two proteins for the three operator sites is different: whereas lambda repressor binds with an affinity OR1 greater than OR2 greater than OR3, the order for cro protein is OR3 greater than (OR1, OR2) . As predicted by these results, cro protein, like the lambda repressor, blocks in vitro transcription of cI and cro from the two divergent promoters that overlap OR . Also as predicted, transcription of cI is turned off at lower cro protein concentrations than is transcription of cro, whereas the opposite order of repression is obtained with lambda repressor . These results describe the molecular mechanism of cro protein action and show that two regulatory proteins can bind to the same three adjacent sites in DNA with markedly different consequences.

Proc Natl Acad Sci U S A, 1978 Apr, 75(4), 1685 - 9
Strand-specific break near the origin of bacteriophage P2 DNA replication; Chattoraj DK; Membrane-associated P2 DNA isolated early after infection under conditions that block replication (amB in phage and rep in Escherichia coli C) was analyzed by electron microscopy . Most DNA was in the form of relaxed circles (40%) and circles with short single-stranded tails (60%) . When this DNA was hybridized with separate strands of linear P2 Hy dis DNA (which provides suitable reference points along the heteroduplex molecules), an interruption was located near the previously mapped origin of P2 DNA replication in one specific strand . The same strand was sometimes extended in the direction consistent with the unidirectional mode of P2 DNA replication . Similar conclusions were reached when the intracellular DNA was analyzed after partial denaturation . These results are consistent with the rolling circle mode of DNA replication.

Nature, 1978 Mar 30, 272(5652), 414 - 23
The relationship between function and DNA sequence in an intercistronic regulatory region in phage lambda; Rosenberg M et al.; rho factor-mediated transcription termination at the tr1 terminator site of bacteriophage lambda is examined . Mutations affecting the termination event are characterised . These mutations define features of the site which seem to be important to terminator function . In addition, other related transcriptional and translational regulatory elements are defined within the region surrounding the termination site . The potential molecular interactions and structural overlaps of these control signals apparently couple the regulation of the decision between lytic and lysogenic growth patterns by phage lambda.

Nature, 1978 Mar 30, 272(5652), 410 - 4
Nucleotide sequence of cro, cII and part of the O gene in phage lambda DNA; Schwarz E et al.; A nucleotide sequence comprising 960 base pairs of bacteriophage lambda DNA has been determined . The sequence includes the entire genes of the regulatory proteins cro and cII, and part of the O gene, together with control elements for their transcription and translation . The right-hand boundaries of the lambdaimm434 and lambdaimm21 substitutions and the cy42 mutation have been located.

Biochemistry, 1978 Mar 21, 17(6), 1092 - 100
Primary structure of the lambda repressor; Sauer RT et al.; The complete covalent structure of the bacteriophage lambda repressor has been determined by sequential Edman degradation, gas chromatographic-mass spectrometric peptide sequencing, and DNA sequencing of the repressor gene cI . The repressor is a single-chain, acidic protein containing 236 amino acids . The amino terminal 40 residues are highly polar and basic . Lysines and arginines in the sequence tend to be clustered.

Biochemistry, 1978 Mar 7, 17(5), 841 - 50
Nucleotide clusters in deoxyribonucleic acids: sequence analysis of DNA using pyrimidine oligonucleotides as primers in the DNA polymerase I repair reaction; Kaptein JS et al.; Pyrimidine oligonucleotides have been shown to prime the E . coli DNA polymerase I repair reaction, specifically and reproducibly . DNA molecules up to 30 nucleotides long have been obtained from the extension of oligopyrimidine primers, 9 to 11 nucleotides long isolated from the complementary (minus) strand of bacteriophage S13 RFDNA using S13 viral DNA as the template molecule . The sequences of the extended primers were determined from mobility shift following separation of partially extended primers by ionophoresis and homochromatography, and by a modification of the "plus" system of Sanger and Coulson (1975) . The 3' leads to 5' exonuclease activity of E . coli DNA polymerase was utilized for the "plus" system in the presence of single dNTPs and also with two dNTPs in the reaction, to give a nearest neighbor type of analysis for sequence confirmation . The ready availability of oligopyrimidine primers from any DNA and the simplification of the "plus" method broaden the range of applicability of the primed DNA polymerase I repair reaction for DNA sequence analysis.

Nature, 1978 Mar 2, 272(5648), 32 - 4
In vivo synthesis and properties of uracil-containing DNA; Warner HR et al.; T4 bacteriophage DNA containing as much as 30% of its thymine replaced by uracil can be synthesised in Escherichia coli deficient in both dUTPase and uracil--DNA glycosidase . This uracil-containing DNA is competent for RNA transcription, and can be packaged into phage which are viable, if the host cells are deficient in uracil--DNA glycosidase activity . If the host cells are not deficient in this glycosidase activity the infecting phage DNA is rapidly attacked, resulting in more than 50% acid-solubilisation of the DNA . The infected cells are inefficiently killed, presumably because of very limited, if any, expression of the phage DNA . These results indicate that this replacement of thymine by uracil in DNA does not seriously impair the biological functionality of T4 DNA, provided the DNA is not subjected to the breakdown (repair) pathway initiated by uracil--DNA glycosidase.

Biophys Chem, 1978 Mar, 8(1), 41 - 51
A unified theory of nucleation-rate-limited DNA renaturation kinetics; Rau DC et al.; DNA renaturations under nucleation-rate-limiting conditions on simple DNA such as bacterial and bacteriophage DNA show significant deviation from ideal second-order kinetics when followed by optical density measurements at 260 nm . Ideal second-order kinetics yield linear plots when the data is plotted in the standard reciprocal second-order (RSO) manner . The observed deviations from ideal second-order behavior take the form of steadily downward-curving RSO plots . In this paper, experiments are presented for E . coli and T2 DNA documenting this non-ideal behavior . Since experiments using T4, T5 and B, subtilis DNA yield identical non-ideal behavior, this behavior appears to be a property of DNA renaturation followed by optical density, not a peculiarity of a particular DNA . Identical non-ideal behavior is also seen in kinetics followed by S1 nuclease assay . A theory is developed to explain this deviation from ideal second-order kinetics . The theory also explains why kinetics followed by hydroxyapatite chromatography show nearly ideal second-order kinetics . In contrast to the approach taken by others in developing equations that describe S1 nuclease monitored reactions, our view is that nonideal second-order kinetics are fundamentally due to the reacton of free single strands to yield partially helical duplex species . Later reactions of these species tend to reduce the deviations from non-ideal second-order kinetics.

J Virol, 1978 Mar, 25(3), 831 - 44
Head maturation pathway of bacteriophages T4 and T2 . III . Isolation and characterization of particles produced by mutants in gene 17; Carrascosa JL et al.; We have isolated and characterized two types of particles produced in comparable amounts by mutants in gene 17: the empty large particle and the empty small particle . Dimensions, morphology, stability, and protein composition of the empty large particle are very similar to those of the capsids or empty heads of mature phage . The other type of particle (empty small particle) is very similar in dimensions and stability to the prehead, but differs in that it is composed of processed proteins (gp23, gp24, IpIII) . Structural analysis has shown that the protein subunits of the empty small particles are arranged in an unexpanded type of lattice (11.2 to 11.3 nm), whereas the empty large particles have an expanded lattice (13 nm) . The characterization of the empty small particle as being composed of cleaved proteins, but still unexpanded, shows that the expansion of the T4 head shell is not necessarily linked to the cleavage of the structural proteins.

J Virol, 1978 Mar, 25(3), 730 - 7
Roles of bacteriophage lambda gene products O and P during early and late phases of infection cycle; Klinkert J et al.; Ring-to-ring (early) replication of bacteriophage lambda DNA was blocked after heat inactivation of the P protein . Rolling circle (late) replication continued for several rounds at the rate reached when the temperature shift was carried out . The same differential effect was observed after inhibition of RNA or protein synthesis during the two different phases of replication . In contrast, inactivation of the O protein resulted in a fast stop of lambda DNA synthesis at early and late times after infection . The results were consistent with the following interpretations . (i) The lambda P gene product plays a role in the initiation of the ring-to-ring replication . (ii) Ring-to-ring replication continues parallel to rolling circle replication, possibly diminishing with time after infection . (iii) The O function is stable in and necessary for the structural integrity of an elongation complex . It is unstable in free form and probably released from such a replication complex after each round of replication at the ring-to-ring stage.

J Bacteriol, 1978 Mar, 133(3), 1427 - 36
Adjacent insertion sequences IS2 and IS5 in bacteriophage Mu mutants and an IS5 in a lambda darg bacteriophage; Chow LT et al.; Using electron microscopic heteroduplex analysis, we have demonstrated that an insertion found in a Mu prophage and in some infectious . Mu deletion-substitution mutants derived from it consists of bacterial insertion sequence IS2 linked directly to IS5 . Other infectious Mu mutants derived from the same lysogen have only IS5 or a portion of IS2 . In addition, we have found that an independent insertion in a transducing phage, lambda 13 dargB2, is IS5 . The ends of IS5 are short, inverted duplications of each other . These observations support the notion that the DNA insertion previously designated IS5 on the basis of a single example in lambda KH100 is a bona fide bacterial insertion sequence.

Genetika, 1978 Mar, 14(3), 502 - 9
{Characteristics of the intragenic recombination of T4B bacteriophage amber mutants under nonpermissive (su-) conditions}; Gordeev VK et al.; Intragenic recombination of bacteriophage T4B amber mutants in early genes 30, 32, 42, 43, 44, 56 and in late gene 7 in su- cells of Escherichia coli B was studied . The frequency of recombination under such conditions was increased in genes 30, 43 and 7, but it was lowered in genes 46 and 44, and was completely inhibited in genes 32, 42 and 56 . The level of stimulation or inhibition of recombination frequencies in early genes was gene-specific and did not depend either on the distances between amber mutations, or on progeny phage maturation delay . On the other hand, the level of recombination stimulation in the late gene 7 was greatly influenced by the distances between amber mutations tested . Wild type alleles arising in su- cells during recombination proved to be functionally active, and their activity caused the increase in progeny phage yield and in a partial removal of phage maturation delay.

Proc Natl Acad Sci U S A, 1978 Mar, 75(3), 1237 - 41
Cell-cell interactions in conjugating Escherichia coli: purification of F pili with biological activity; Helmuth R et al.; A mutant of the F sex factor has been isolated that produces more F pili per cell than does the wild-type F factor . F pili have been purified in milligram amounts from cells carrying either the mutant or the wild-type sex factor . The technique described yields F pili of up to 99% purity that can specifically bind to Escherichia coli cells and that bind to and reversibly inactivate male-specific bacteriophages . The F pilin subunit has a molecular weight of 10,750 and purified F pili have a buoyant density of 1,200 g/cm3.

Eur J Biochem, 1978 Mar, 84(1), 233 - 9
Replication of M-13 DNA in plasmolysed Escherichia coli cells . Structure of a replicative intermediate with restricted binding of intercalating dyes; Kessler-Liebscher BE et al.; DNA molecules with restricted binding of intercalating dyes are observed as replicative intermediates during the replication of bacteriophage M-13 duplex DNA in a cellular system in vitro prepared by plasmolysis of M-13-am5-infected Escherichia coli cells . Restriction of dye binding is abolished by heating the DNA to 80 degrees C, but can be recovered by slow cooling of the heat-treated DNA . Radioactive pulse-label incorporated by these molecules is found exclusively in elongated viral strands of more than one genome length . In the electron microscope this DNA fraction is seen to contain a significant number of duplex DNA rings with two single-stranded tails protruding from the same region of the ring . It is proposed that these structures arise by branch migration during the isolation of replicating molecules containing only one single-stranded tail . The topological constraint in these molecules is most likely caused by base-pairing between partially complementary regions of the two single-stranded tails.

J Bacteriol, 1978 Mar, 133(3), 1478 - 83
New major outer membrane proteins found in an Escherichia coli tolF mutant resistant to bacteriophage TuIb; Foulds J et al.; Cell envelopes prepared from an Escherichia coli tolF strain selected as resistant to phage TuIb contained a new major outer membrane protein related to outer membrane proteins Ia and Ib . The strain that produces this protein is a tolF par double mutant but contains an additional mutation leading to the production of the new major outer membrane protein . Antibiotic sensitivity lost as a result of the tolF mutation is regained in strains that contain the new major outer membrane protein . This indicates that this protein functions to restore the selective permeability of the outer membrane to low-molecular-weight hydrophilic molecules.

J Bacteriol, 1978 Mar, 133(3), 1287 - 94
Replication of colicin E1 plasmid DNA in vivo requires no plasmid-encoded proteins; Donoghue DJ et al.; A derivative of bacteriophage lambda containing a colicin E1 plasmid replicon was constructed by recombinant DNA techniques . This phage, lambdacol100, has two functional modes of DNA replication; it can replicate via either plasmid or phage replication systems . lambdacol100 has been used to introduce the colicin E1 plasmid replicon into Escherichia coli previously treated with chloramphenicol to block protein synthesis . Under these conditions, lambdacol100 DNA is replicated normally as a colicin E1 plasmid . This suggests that colicin E1 plasmid replication in vivo does not require any plasmid-encoded proteins.

Infect Immun, 1978 Mar, 19(3), 1076 - 82
Cellular release of heat-labile enterotoxin of Escherichia coli by bacteriophage induction; Gemski P et al.; Treatment of some enterotoxigenic Escherichia coli strains with the antibiotic mitomycin C resulted in lysis of the bacteria . Heat-labile enterotoxin (LT) activity of culture filtrates, determined by means of the Y-1 adrenal cell assay, increased dramatically as lysis of the culture proceeded . Further studies with E . coli strains 263 and B21-4 revealed that lysis is due to mitomycin C induction of vetetative development of a temperature bacteriophage . These findings suggest that the elevated levels of LT detected after mitomycin C treatment reflect the lytic release of cell-bound LT rather than the induction by mitomycin C of de novo toxin biosynthesis . Comparable increases in LT activity also resulted from thermal induction of a phage P1Cm lysogen of strain 263 or from sonic disruption of enterotoxigenic strains.

Proc Natl Acad Sci U S A, 1978 Mar, 75(3), 1270 - 3
Addition of mononucleotides to oligoribonucleotide acceptors with T4 RNA ligase; Kikuchi Y et al.; RNA ligase induced by bacteriophage T4 catalyzed the addition of nucleoside 5',3'-diphosphates to oligoribonucleotide acceptors in the presence of ATP . The reactions proceeded in equimolar concentrations of donors and acceptors . Several oligonucleotides of defined sequence were synthesized by this method in yields of 28-68% . The enzyme required the phosphate ester at the 3' position of the donor molecule, nucleoside 5',2'-diphosphates being unable to serve as donors . Thymidine 5',3'-diphosphate was active as a donor for the enzyme . The ligation product, (Ap)2ApCp, was also obtained from the reaction of (Ap)2A and 5'-adenylylated cytidine 5',3'-diphosphate (A5'pp5'Cp) with RNA ligase in the absence of ATP . These results show that the minimal substrate for RNA ligase is a nucleoside 5',3'-diphosphate.

Proc Natl Acad Sci U S A, 1978 Mar, 75(3), 1081 - 5
Nucleotide sequences of the separate origins of synthesis of bacteriophage G4 viral and complementary DNA strands; Fiddes JC et al.; 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 observed during synthesis in vitro of the G4 complementary DNA strand {Bouche, J.P., Rowen, L . & Kornberg, A . (1978) J . Biol . Chem., in press} . This G4 origin shows extensive sequence homology with the bacteriophage lambda origin of DNA replication {Denniston-Thompson, K., Moore, D . D., Kruger, D . E., Furth, M . E . & Blattner, F . R . (1977) Science 198, 1051-1056} . The sequence around the site in gene A at which G4 viral DNA strand synthesis is initiated by the nicking action of the cistron A protein is very similar to that of bacteriophage phiX174 . An (A + T)-rich stretch flanked by (G + C)-rich sequences may be involved in the interaction between the DNA and protein.

Nucleic Acids Res, 1978 Mar, 5(3), 825 - 33
Polynucleotide kinase from a T4 mutant which lacks the 3' phosphatase activity; Cameron V et al.; Polynucleotide kinase from E . coli infected with the PseT 1 mutant of bacteriophage T4 has been isolated . The PseT 1 enzyme purifies similarly to normal polynucleotide kinase and effectively transfers the gamma phosphate of ATP to the 5' terminal hydroxyl of DNA and RNA . The PseT 1 and normal enzymes require similar magnesium ion concentrations, have the same pH optima and are both inhibited by inorganic phosphate . However, the PseT 1 enzyme is totally lacking the 3' phosphatase activity associated with normal polynucleotide kinase . The PseT 1 enzyme is a useful tool for the preparation of oligonucleotides with 3' and 5' terminal phosphates for use as susbstrates for RNA ligase.

Mol Gen Genet, 1978 Feb 27, 159(3), 259 - 68
Sequence homology in DNA molecules of temperate phages phi81, phi80 and lambda; Niwa O et al.; Homology maps between bacteriophages phi81, phi80 and lambda were constructed on the basis of electron microscopy observation of DNA heteroduplexes . In phi81/phi80 heteroduplex, the left half and the right terminal region of 13% the total molecular length were highly homologous, while the remaining region covering the early gene cluster was entirely nonhomologous . In phi81/lambda heteroduplex, high-degree homologies were detected at the left 14% terminal region covering the head gene cluster, the central 3.8% region covering the att-int-xis region and the 1.3% Q homology region . Low-degree homologies of shorter length were scattered at the tail gene cluster, b2 region, cIII region, PQ region and SR region . Comparing our results with the homology maps of other lambdoid phages reported by Simon et al . (1971) and Fiandt et al . (1971), a phylogenic relation of phi81 to other lambdoid phages and the role of recombination in the course of divergence of lambdoid phages are discussed.

Mol Gen Genet, 1978 Feb 27, 159(3), 301 - 9
Construction and properties of recombinant plasmids containing the rII genes of bacteriophage T4; Selzer G et al.; The EcoRI digestion products of phage T4 DNA have been examined using a phage DNA transformation assay . A 2.6 X 10(6) Dalton fragment was found to contain the rII genes . This fragment was purified and then treated with HindIII endonuclease . The cleavage products were ligated to the vector plasmid pBR313 and viable recombinant plasmids recovered . A genetic assay was employed to demonstrate that the recombinants contained T4 DNA and to localize on the phage genetic map the EcoRI and HindIII sites cleaved during the construction of the plasmids . Preliminary characterization suggests that a fragment covering the beginning of the rIIA gene possibly contains a promotor which is active in uninfected cells.

Biochim Biophys Acta, 1978 Feb 16, 517(2), 319 - 28
Location of the cooperative melting regions in bacteriophage fd DNA; Tachibana H et al.; Differential melting profiles of the linear replicative form (RF-III) DNA of bacteriophage fd, of the fragments obtained by the restriction endonuclease R.HinHI and of those obtained by R.Hga were investigated . With these results a physical map which locates the cooperative melting regions on the DNA was constructed, and compared with the genetic map.

Mol Gen Genet, 1978 Feb 16, 159(2), 171 - 8
Transposition of a DNA sequence determining kanamycin resistance into the single-stranded genome of bacteriophage fd; Herrmann R et al.; Derivatives of bacteriophages fd which transduce kanamycin resistance were selected after growth of the phage in an E . coli strain that carried transpoon 5 (Tn5) . Different clones of transducing phage and their DNAs were characterized by gel electrophoresis, electron microscopy, and by their ability to multiply in the absence of helper phage . Integration of the intact transposon into the full size phage genome was correlated with an increase in size of the phage particle from 0.95 mu to 1.7 mu, and with the appearance in the phage DNA of the stem loop structure characteristic for single-stranded Tn5 DNA . In non-defective phages the site of insertion was mapped by heteroduplex analysis within the intergenic region of the phage genome . Defective transducing phages were characterized as an insertion of Tn5 into a phage gene, and/or as a partial deletion or duplication of phage and transposon DNA . The size of the transducing phage from different defective clones varied from 0.6 mu to 3.0 mu and was directly proportional to the DNA content . These results demonstrate that filamentous bacteriophage are highly capable to replicate and package very different amounts of foreign DNA.

Mol Gen Genet, 1978 Feb 16, 159(2), 143 - 9
Explanations accounting for transduction by bacteriophage lambda in maltose negative bacteriophage lambda resistant mutants of Escherichia coli K-12; Braun-Breton C et al.; Entry of DNA from lambda phages particles into lambdarMAl- mutants of Escherichia coli K-12 is shown to be due to two distinguishable processes . One, residual transduction, results from a low level expression of lamB . The other one, background transduction, is independent of gene lamB . Interpretations are presented for these results . It is propos that residual transduction is due to a weak promoter pB3 located within or near the distal part of the gene preceeding lamB in the same operon . It is proposed that background transduction is due to a secondary receptor structure for phage lambda . Finally a tentative hypothesis relatin pB3 to insertion sequences is presented.

Biochim Biophys Acta, 1978 Feb 16, 517(2), 531 - 4
Bacteriophage phiX174 growth in an Escherichia coli dnaIts mutant, KS810; Sakai H et al.; 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.

Mol Gen Genet, 1978 Feb 7, 159(1), 107 - 10
Protection of foreign DNA against host-controlled restriction in bacterial cells . I . protection of F' plasmid DNA by preinfection with bacteriophages T3 or T7; Kruger DH et al.; Foreign F'lac plasmid DNA which is introduced into potentially restricting E . coli recipient cells can be protected from restriction by preinfecting the recipient cells with UV-inactivated T3 or T7 bacteriophages which express the ocr gene function . The recipient cells survive and are able to replicate themselves as well as the newly acquired plasmid.

Nature, 1978 Feb 2, 271(5644), 417 - 20
Nucleotide sequence of the origin of replication in bacteriophage phiX174 RF DNA; Langeveld SA et al.; 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.

J Gen Virol, 1978 Feb, 38(2), 251 - 61
Defective particle assembly in wild type P2 bacteriophage and its correction by the lg mutation; Bertani G et al.; The mutation lg of phage P2 has been located on the genetic map of P2 to the right of, and closely linked to, the del2 deletion, probably within tail gene F . The lg mutation causes larger burst sizes, compared with the wild type, especially at high incubation temperatures . The frequency of defective particles is lower in preparations of P2 lg than in those of wild type P2 . It seems that the mutation lg improves the efficiency of particle assembly.

J Virol, 1978 Feb, 25(2), 695 - 7
Incorporation of label from ribose into 5-(4',5'-dihydroxypentyl) uracil of bacteriophage SP15 DNA; Walker MS et al.; Radioactively labeled ribose was incorporated into the glucosylated deoxynucleoside monophosphate of 5-(4',5'-dihydroxypentyl)uracil of bacteriophage SP15 DNA to a greater extent than into the other pyrimidine deoxynucleoside monophosphates . Results from formic acid hydrolysis of the deoxynucleoside monophosphates to their bases suggest that label from ribose is incorporated into the dihydroxypentyl side chain of 5-(4',5'-dihydroxypentyl)uracil.

J Gen Microbiol, 1978 Feb, 104(2), 287 - 97
The biochemical and genetic basis for high frequency thiomethyl galactoside resistance in lambda,lambdadg lysogens of Escherichia coli; Raney ME et al.; In a culture of Escherichia coli K12 gal (lambdadg), cells which form large colonies on agar plates containing galactose and thiomethyl beta-D-galactoside (TMG) appear at high frequency . These clones are resistant to growth inhibition by TMG on galactose minimal medium . Biochemical studies of the steady-state levels of galactokinase and UDPgalactose 4-epimerase suggest that the resistant clones have extra copies of the genes for the galactose-metabolizing enzymes . The mutation for TMG resistance is not located in either the bacterial or the bacteriophage genome, but is probably due to an aberrant association between cell and prophage DNA . Mapping the TMG-resistant characteristic by phage P1 indicates that TMG-resistant bacteria posses at least two GAL+ OPERONS, ONE OF WHICH IS COTRANSDUCIBLe with bio+ . In addition, TMG-resistant bacteria behave like lambdadg polylysogens when challenged with the phage lambdaI90c17 . From these genetic experiments we conclude that TMG-resistant bacteria arise by duplication of the lambdadg prophage . Finally, gal+ bacteria which carry a single, additional, lambdadg prophage are TMG-resistant . TMG resistance is probably a gal+ gene dosage effect.

Gene, 1978 Feb, 3(1), 29 - 38
Current status of coliphage lambda EK2 vectors; Shalka A; This article summarizes the rationale behind the design of standardized laboratory tests for certification of bacteriophage lambda EK-2 vector systems . A discussion and description of the six vector systems which have been certified by the U.S . National Institutes of Health are also included . An appendix describes the officially approved laboratory tests in detail.

J Virol, 1978 Feb, 25(2), 562 - 9
Purification and structures of recombining and replicating bacteriophage T7 DNA; Langman L et al.; During the infection of Escherichia coli by bacteriophage T7, there is a gradual conversion of host DNA to T7 DNA . Recombination and replication occur during this time . We have devised a new way of examining the physical structures of the intermediates of these processes . It is based on the observation that there are no sites in T7 DNA susceptible to cleavage by the restriction endonuclease EcoRI . E . coli DNA, on the other hand, is susceptible to degradation by EcoRI . Thus, phage and host DNA can be separated by sucrose gradient centrifugation after treatment with EcoRI . Concatemeric T7 DNA contains a high proportion of branched, gapped, and whiskered structures . These appear to be intermediates of replication and recombination . This approach also monitors the conversion process from host to T7 DNA.

J Virol, 1978 Feb, 25(2), 527 - 34
Exclusion of bacteriophage T1 by bacteriophage lambda . I . Early exclusion requires lambda N gene product and host factors involved in N gene expression; Christensen JR et al.; Two modes of exclusion of T1 by lambda are distinguished . "Early" exclusion depends on gene N, but not on gene Q . It is at least partially ineffective against T1am23 . "Late" exclusion depends on gene Q and effects T1am23 as well as T1+ . Early exclusion is a direct effect of N gene product, rather than N gene being required for the expression of some other lambda gene . Three host mutations, groN, nusA, and nusB, known to interfere with lambda replication by affecting N gene expression, also interfere with the ability of lambda to exclude T1.

J Virol, 1978 Feb, 25(2), 491 - 9
Late effect of bacteriophage T4D on the permeability barrier of Escherichia coli; Thompson S et al.; Cold centrifugation of lysis-inhibited Escherichia coli B infected with wild-type T4D results in extensive lysis beginning around 20 min after infection at 37 degrees C . Infection with an e mutant, which fails to make lysozyme, prevents lysis, but does not prevent a marked loss of K+ and Mg3+ . The t gene product, thought to disrupt the cytoplasmic membrane in natural lysis, is not required for this handling-induced cation loss or lysis . Three lines of evidence argue that late protein synthesis is required to develop this potential for cation loss; the potential does not develop in infections by: (i) mutants defective in DNA synthesis, (ii) mutants defective in gene 55, and (iii) wild-type T4 when chloramphenicol is added at 6 min after infection . All late mutants examined, which are blocked in the major pathways of morphogenesis, do not prevent development of the potential . The evidence argues for a new, late effect of T4 infection on the cytoplasmic membrane.

J Bacteriol, 1978 Feb, 133(2), 884 - 96
Expression of the uvrB gene of Escherichia coli: in vitro construction of a pMB9 uvrB plasmid; Pannekoek H et al.; Bacteriophage lambdab2att2 {lambdab2cI857intam6(deltabioAB)bioFCD+uvrB+phr+} codes for a function(s) that confers UV resistance (Uvr+) and reactivation of irradiated phage (Hcr+) to an Uvr-Hcr-Escherichia coli strain . It was demonstrated that these functions are expressed under the control of bacterial regulatory elements located on lambdab2att2 DNA . The location of the E . coli uvrB gene on the DNA of this transducing phage was established by heteroduplex and restriction-enzyme analyses . Recombinant DNA molecules were constructed in vitro from plasmid pMB9 (Tcr), as the vector, and an EcoRI fragment (Eco-RI-F) of lambdab2att2 DNA . The resulting plasmid, designated pNP5, has a molecular weight of 5.1 X 10(6) and replicates in a relaxed fashion . Transformation of E . coli uvrB with plasmid pNP5 resulted in clones that are Uvr+ Tcr . Irradiation of bacteria transformed with plasmid pNP5 with low UV doses revealed a complete restoratation of the Uvr+ phenotype by the presence of the cloned EcoRI-F DNA, while only a partial restoration was observed after irradiation with high UV doses . Likewise, the Hcr+ character was also partially restored due to the presence of pNP5 . No correlation was found between the acquired Uvr+, Hcr+ properties, and the presence of correndonuclease II activity in an extract of bacteria that harbor plasmid pNP5.

J Bacteriol, 1978 Feb, 133(2), 549 - 57
Isolation of specialized transducing bacteriophages carrying the structural genes of the hexuronate system in Escherichia coli K-12: exu region; Mata M et al.; In Escherichia coli HfrH 58, isolated by Shimada et al., a heat-inducible phage has been integrated in a secondary attachment site . We have characterized tha nature of the lambda integration . The exuR regulatory gene is inactivated by prophage integration . Genetic and biochemical analysis indicated a gene order: uxaA-uxaC-exuT-(exuR')-lambdaNRAJ (exuR'') . By induction of HfrH 58, one class of deletions extending into the exu region was obtained . Analysis of these deletions confirms the exu region topography and the regulatory mechanism of the hexuronate system previously described . It has been possible to regenerate a functional exuR gene by prophage exision . Various lambda transducing particles plaque-forming and defective transducing phages carrying the left part or the right part of the exu region, have been derived from the secondary site lysogen HfrH 58 . A phage carrying the entire exuR region was constructed by a cross between these two types of phage . The construction and characterization of these exu transducing phages are presented.

Eur J Biochem, 1978 Feb 1, 83(1), 59 - 66
Initiation of lambda DNA replication in vitro promoted by isolated P-gene product; Klein A et al.; The product of the P gene of bacteriophage lambda was isolated from heat-induced lambda-lysogenic Escherichia coli cells . It was found to bind to DNA, to be devoid of nuclease activity acting on double-stranded lambda DNA and of nicking/closing activity . Initiation of lambda DNA replication promoted by the P-gene product in a complementation assay in vitro was sensitive to rifampicin . Sedimentation analysis of the products and their hybridization to separated lambda DNA strands indicate that lambda DNA was formed in a reaction similar to ring-to-ring replication in vivo . The reaction was symmetric from the beginning, i.e . both lambda DNA strands were copied without delay.

Int J Radiat Biol Relat Stud Phys Chem Med, 1978 Feb, 33(2), 105 - 20
Gamma-ray induced double-strand breaks in DNA resulting from randomly-inflicted single-strand breaks: temporal local denaturation, a new radiation phenomenon?
Van Der Schans GP.
The induction of single- and double-strand breaks in DNA by gamma-rays has been measured . The maximum number of nucleotide pairs (a) between two independently induced single-strand breaks in opposite strands of the DNA which cannot prevent the occurrence of a double-strand break was found to amount to about 16 . This value did not differ significantly for the four types of bacteriophage DNA investigated (T4, T7 and PM2 DNA, and replicative form DNA of phage phiX174) and was the same in 10(-2) M phosphate buffer containing 0, 0.5 or 1 M NaCl . In 10(-3) M phosphate buffer a was 34 nucleotide pairs . Evidence is presented that the relatively large value of a has to be ascribed at least partly to a temporal local denaturation accompanying the induction of a single-strand scission . A contribution of base damage that labilizes the DNA-helix, between two single-strand breaks to the high value of a can not be excluded.

Proc Natl Acad Sci U S A, 1978 Feb, 75(2), 804 - 8
Regulation of transcription of the late genes of bacteriophage T7; McAllister WT et al.; The transcription program of bacteriophage T7 in vivo was analyzed by hybridizing T7 mRNAs, labeled at intervals after infection, to Hpa I restriction fragments of T7 DNA . Transcripcion of the late genes is temporally regulated: class II genes are transcribed between 4 and 16 min after infection; most class III genes are transcribed from 8 min after infection until lysis . Genes 8--10 are transcribed as both class II and class III genes . The rate of T7 RNA synthesis decreases sharply at 10 min after infection . The rapid decrease in the rate of T7 RNA synthesis and the shutoff of class II RNA synthesis were not observed in cells infected with phage defective in gene 3.5 (lysozyme) . Although the decrease in the rate of T7 RNA synthesis is independent of DNA replication, the failure to shut off class II RNA synthesis normally in 3.5-- -infected cells may reflect the role of T7 lysozyme in DNA replication . In vitro, the regions of T7 DNA transcribed by the phage RNA polymerase were found to be dependent upon ionic conditions.

Proc Natl Acad Sci U S A, 1978 Feb, 75(2), 774 - 8
Construction and characterization of an Escherichia coli plasmid bearing a functional gene G of bacteriophage phiX174; Humayun MZ et al.; 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 copy of phiX174 gene G . Three different bacterial strains that are nonpermissive for am9, a gene G amber mutant, have been transformed with pphiXG . The transformants are now permissive for this gene G mutant, but not for the gene A or E mutants that have been tested . This paper describes the construction and the biochemical characterization of this plasmid, pphiXG, and describes some of the biological properties exhibited by the pphiXG-bearing strains.

Biochim Biophys Acta, 1978 Jan 26, 517(1), 55 - 64
Synthesis of alpha3 phage DNA in replication mutants of Escherichia coli; Taketo A et al.; Host functions for DNA replication of bacteriophage alpha3, a representative of group A microvirid phages, were studied using dna and rep mutants of Escherichia coli . In dna+ cells, conversion of phage alpha3 single-stranded DNA (SS) into the double-stranded replicative form (RF) was insensitive to 30--150 microgram/ml of chloramphenicol, 200 microgram/ml of rifampicin, 50 microgram/ml of nalidixic acid, or 200 microgram/ml of novobiocin . At 43 degrees C, synthesis of the parental RF was inhibited in dnaG and dnaZ mutants, but not in dnaE and rep strains . Replication of phage alpha3 progeny RF was prevented by 50 microgram/ml of mitomycin C (in hcr+ bacteria), 50 microgram/ml of nalidixic acid or 200 microgram/ml of novoviocin, but neither by 30 microgram/ml of chloramphenicol nor by 200 microgram/ml of rifampicin . Besides dnaG and dnaZ gene products, dnaE and rep functions were essential for progeny RF synthesis . Host factor dependence of alpha3 was relatively simple and, in contrast with phages phiX174 and G4, alpha3 did not require dnaB and dnaC(D) activities.

J Biol Chem, 1978 Jan 25, 253(2), 574 - 84
Gene 4 protein of bacteriophage T7 . Characterization of the product synthesized by the T7 DNA polymerase and gene 4 protein in the absence of ribonucleoside 5'-triphosphates; Kolodner R et al.; DNA polymerase and gene 4 protein of bacteriophage T7 catalyze extensive DNA synthesis on duplex phage T7 or PM2 DNA templates containing single strand breaks . A variety of physicochemical techniques have been used to characterize the DNA product synthesized in this reaction in the absence of ribonucleoside 5'-triphosphates . Pyknographic and sedimentation analyses reveal that all of the newly synthesized DNA is covalently attached to the template DNA . Analysis by electron microscopy shows the major portion of the product molecules synthesized on duplex T7 DNA templates to consist of a double-stranded branch attached to an intact template molecule . Using PM2 DNA templates, the predominant product consists of a double-stranded branch attached to the circular PM2 DNA template . Analyses of these product molecules indicate that DNA synthesis by the gene 4 protein and T7 DNA polymerase is initiated at single strand breaks in the duplex DNA and that synthesis is accompanied by extensive displacement of one of the parental strands . At later times in the reaction, a portion of the 3'-hydroxyl terminus of the newly synthesized DNA is displaced from the template by branch migration and is used as a primer by the DNA polymerase to copy the displaced 5' single-stranded parental strand to form a duplex branch.

J Biol Chem, 1978 Jan 25, 253(2), 566 - 73
Gene 4 protein of bacteriophage T7 . Purification physical properties, and stimulation of T7 DNA polymerase during the elongation of polynucleotide chains; Kolodner R et al.; With the use of an in vitro complementation assay to measure activity, the gene 4 protein of bacteriophage T7 has been purified 1000-fold to yield a nearly homogeneous protein . The purified gene 4 protein is a single polypeptide having a molecular weight of 58,000 . In addition to being essential for T7 DNA replication in vivo and in vitro, the gene 4 protein is required for DNA synthesis by the purified T7 DNA polymerase on duplex T7 DNA templates . In the absence of ribonucleoside 5'-triphosphates, DNA synthesis by the gene 4 protein and the T7 DNA polymerase is dependent on phosphodiester bond interruptions containing 3'-hydroxyl groups (nicks) in the duplex DNA . The reaction is specific for the T7 DNA polymerase, but any duplex DNA containing nicks can serve as template . The Km for nicks in the reaction is 3 x 10(-10) M.

Arch Immunol Ther Exp (Warsz), 1978, 26(1-6), 571 - 6
Ultrastructure and antigenic differentiation of bacteriophages of the CII and CIII morphological groups; Krzywy T et al.; 45 bacteriophages of two morphological groups (CII and CIII) were serologically tested . The results point out the possibility of serological differentiation of bacteriophages within one morphological type . The aim of the undertaken studies was to examine ultrastructure and antigenic differentiation of bacteriophages belonging to CII and CIII morphological groups.

Zentralbl Bakteriol Naturwiss, 1978, 133(2), 180 - 7
{On the effect of some morpholinium compounds on the multiplication of RNA viruses (author's transl)}; Kluge S et al.; In the present paper the authors report about the effect of N,N-dimethylmorpholinium chloride (DMMC), N,N-dimethyl-2-oxomorpholinium chloride (DMOMC), and N,N-diethyl-2-oxomorpholinium chloride (DEOMC) on the multiplication of tobacco mosaic virus (TMV), potato virus X (PVX), and cucumber mosaic virus (CMV) as well as the plaque formation by the RNA phages M 12, f 2, and Qbeta . The used morpholinium compounds do not influence strikingly the multiplication of phytoviruses . The results found by serological procedure and by bio-assay are indicated concordantly by the two methods . The plaque formation by bacteriophages is not influenced by DMMC, but enhanced significantly by DMOMC and DEOMC . These effects might be caused by the different hydrolytical behaviour of the morpholinium compounds tested.

Genetika, 1978, 14(7), 1146 - 52
{Genetic study of bacteriophage phi81 . II . Gene localization in the right arm of the phage chromosome and a comparison of phage phi81 with phages lambda and phi80 in regard to gene functions}; Sineokii SP et al.; Data on genetic investigation on lambdoid bacteriophage phi81 made possible to localize the cos site on the prophage genetic map . Four essential genes and the gene c1 are located in the right arm of the phage genetic map . Regulatory genes of phage phi81 are found to be uncapable of functional substitution of lambda phages regulatory genes N and Q . It is discovered that some late genes of phage phi80 can be substituted with respective phage phi81 genes . No substitution possibility was observed for a number of early genes of phage phi80.

J Virol, 1978 Jan, 25(1), 73 - 7
Mutator and antimutator phenotypes of suppressed amber mutants in genes 32, 41, 44, 45, and 62 in bacteriophage T4; Watanabe SM et al.; Bacteriophage T4 genes 32, 41, 44, 45, 56, and 62 are essential to DNA replication . Amber mutants (suppressed by su+1, su+2, or su+3 bacteria) in these genes were examined for any mutator or antimutator effects on the reversion of a transition mutation . In every case except for mutations in gene 56, elevated or lowered error frequencies were observed . These results indicate the importance of all of the replicative proteins in the determination of error frequency.

Acta Biol Med Ger, 1978, 37(11-12), 1639 - 44
{Effect of temperature on formation of lysozyme in E . coli CRT 266 (dnaB ts) after infection with bacteriophage T3}; Michel S et al.; 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.

Microbios, 1978, 20(80), 125 - 31
Effect of chloramphenicol and cyanide on the increase in UV resistance of intracellular bacteriophage T1; Mosin AF; The effects of chloramphenicol and cyanide on the increase in UV resistance of intracellular phage T1 infecting cells of E . coli B or E . coli Bs-1 were investigated . The inhibitiors were added to the cells 3 min prior to infection and to the complexes of phage-bacteria 3.5 and 6.5 min after adsorption of phage by the cells . The data obtained are not in agreement with the suggestion that increase in UV resistance of intracellular phage is mainly due to the accumulation of phage DNA inside the host cells . It is suggested that a very important role in this resistance is played by the interaction of phage DNA with the cell membranes.

Microbios, 1978, 20(80), 115 - 23
Some features of the reaction of intracellular bacteriophages T1 to UV irradiation; Mosin AF; The reaction of complexes pf phage T1-cells of E . coli B or E . coli Bs-1 to UV irradiation was investigated . The complexes were irradiated at various stage of infection, and their survival, extent of Hcr and Phr, were evaluated . It was found that the UV resistance of phage DNA in the second half of the latent period fluctuates . Hcr after UV exposure at these stages of infection operates in a small volume . The ability of intracellular phage to photoreactivate when cells of E . coli B were infected is constant after irradiation at many stages of infection, except the early ones . In the complexes of phage T1-bacteria of E . coli Bs-1 this ability declines while infection is promoted . The daughter phage particles released from UV irradiated complexes undergo Phr and Hcr only after irradiation at the late stages of infection . This was not the cases when complexes of phage-bacteria were irradiated during the first half of the latent period . A possible tole of UV-damaged phage DNA in propagation of infection and in maturation of phage particles is discussed.

Arch Invest Med (Mex), 1978, 9(2), 417 - 28
{Description of a method for measuring sera with a high level fo IgE: test through the inactivation of anti-IgE covered phages}; Fresan-Orozco C et al.; The Fab fragment of an anti-IgE serum was conjugated with the bacteriophage T4 through the use of glutaraldehyde . The conjugated phage was inactivated by human sera which contained IgE . The degree of inactivation allowed to make a distinction between the sera of normal individuals and that of those in whom it is known that high levels of Ig E exist, as in patients with allergic diseases . The method is quite sensitive, economical and does not require costly equipment . Besides, the conjugated phage is preserved for prolonged periods of time.

Acta Biochim Pol, 1978, 25(1), 37 - 47
The host cell fraction that increases the infectivity of bacteriophage f2; Chroboczek J; A fraction that increases infectivity of bacteriophage f2 was isolated from uninfected E . coli cells . The greatest effect was obtained when the fraction was added to the phage reconstituted in vitro . The fraction isolated from the ribosome-free supernatant consisted of proteins, lipids, carbohydrates, and unidentified material . Cleavage of protein by the treatment with trypsin did not significantly affect the infectivity-restoring activity . It is suggest that lipids may play an essential role in the activity of the fraction isolated from the host cell.

Z Allg Mikrobiol, 1978, 18(2), 115 - 21
{Effect of 1,3,5-triazines on various bacteriophages and their hosts}; Stenz E et al.; In the agar diffusion test 24 triazines were investigated with regard to their action on the mulplication of DNA phages (lambda and LPP-1) and RNA phages (M12 and Qbeta) . In several cases the amount of plaques was diminished or increased depending on the kind of triazine and virus . The investigations demonstrate the triazines to be able to interfere with the formation of plaques by virulent and temperate viruses of procaryotes.

Mol Biol (Mosk), 1978 Jan-Feb, 12(1), 116 - 22
{Phenomenon of w-reactivation in plasmids}; Khodkova EM et al.; An analysis of the action of the bacterial repair system on the UV-irradiated pMB9 plasmid has been carried out . It has been shown that the UV-irradiated plasmid is repaired in the bacteria similarly to the DNA of bacteriophage (lambda): the effectiveness of the UVR-system is lowered two-three times, and the postreplicativing REC system acts only at low doses of the UV-light . The phenomenon of omega-reactivation is observed both with plasmid and phage DNAs.

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