Publications

superinfection immunity and prophage repression in phage p1 and p7. iii. induction by virulent mutants.		1977	860403
conditions critical for optimal visualization of bacteriophage adsorbed to bacterial surfaces by scanning electron microscopy.	the potential of scanning electron microscopy as a tool for the detection of viruses on cell surfaces has been studied using bacteriophage p1 adsorbed to shigella dysenteriae as a model system. viral particles were readily detectable by scanning electron microscopy on the surface of infected cells which were fixed with glutaraldehyde followed by postfixation in oso4 and prepared by critical point drying. the virus-studded surface of the infected cells differed markedly from the relatively smooth ...	1975	806704
gene transfer to myxobacterium by escherichia coli phage p1.	myxococcus xanthus is a bacterium with an interest for studies of development because it has an organized multicellular phase in its life cycle. bacteriophage pl can adsorb to m. xanthus and inject its dna into this organism despite the wide taxonomic gap separating myxococcus from escherichia coli, the source of pl. a specialized transducing derivative of pl, called plcm, can carry a gene for chloramphenicol resistance from e. coli into m. xanthus and generate unstable drug-resistant strains.	1975	803710
genetic mapping of xtha, the structural gene for exonuclease iii in escherichia coli k-12.	the genes xtha, pnca, and pabb were ordered relative to others by two- and three-factor transductional crosses with bacteriophage p1. the genes studied span 2 min (2%) of the genetic map of escherichia coli k-12 in the clockwise sequence phes-pfkb-xtha-pnca-gap-pabb-fadd. eleven independently derived xth mutations were examined; all were known to affect exonuclease iii and its associated endonuclease ii activity, and all were mapped in the xtha region. pnca mutations were found to confer resista ...	1976	780339
novel genotypes among transductants made with bacteriophage p1 lysates from an f14 merogenote strain of escherichia coli k-12.	among p1 transductants in escherichia coli k-12 that were selected for the proximal and distal markers from the large f14 merogenote, a variety of unusual genotypes were found. as earlier workers had found, one class of these could transfer the proximal genes (argh, metb) and distal genes (ilvedac) of the f14 during conjugation. these f14 genes could be transferred into reca recipients, indicating that they were carried on an f-merogenote rather than on an hfr chromosome. the transduced f-meroge ...	1976	776932
effects of the phage p1 restriction system on coliphage phi w: degradation and complex formation of phage phi w dna.	growth of phages phi w and t7 was restricted in escherichia coli lysogenic for phage p1. only a fraction of the infected cells gave burst of phages. cells permitting phage growth gave normal burst size. host strains carrying p1 mutants with defective endonuclease gave no restriction of phages t7 and phi 3, the latter a host-range mutant of phi w. degradation but not modification of parental phage dna could be demonstrated. although no dna, rna or protein was synthesized in phi w infected p1 lyso ...	1976	772170
periplasmic protein related to the sn-glycerol-3-phosphate transport system of escherichia coli.	two-dimensional gel electrophoresis of shock fluids of escherichia coli k-12 revealed the presence of a periplasmic protein related to sn-glycerol-3-phosphate transport (glpt) that is under the regulation of glpr, the regulatory gene of the glp regulon. mutants selected for their resistance to phosphonomycin and found to be defective in sn-glycerol-3-phosphate transport either did not produce glpt or produced it in reduced amounts. other mutations exhibited no apparent effect of glpt. transducti ...	1976	770459
phage p1 carrying kanamycin resistance gene of r factor.		1976	769309
superinfection immunity and prophage repression in phage p1. iv. the c1 repressor bypass function and the role of c4 repressor in immunity.		1978	664217
miniplasmids of bacteriophage p1. i. stringent plasmid replication does not require elements that regulate the lytic cycle.		1978	642010
a characterization of bacteriophage p1 dna fragments cloned in a lambda vector.		1979	462805
isolation and characterization of cloned fragments of bacteriophage p1 dna.		1979	452412
[transgenosis with participation of plasmid rp1; indications of the presence of a "composit plasmid" in an interspecies hybrid of escherichia coli].	one of the transconjugants (1-7) obtained by the authors earlier in the conjugation of escherichia coli j-62 with pseudomonas aeruginosa 1822, besides the plasmic rp1 has acquired the ability to grow without proline and tryptophan. the detailed analysis has shown that in the conjugation of the transconjugant 1-7 with different strains of e. coli the plasmic rp1 and chromosomal genes were transmitted together, but in transduction--by means of bacteriophage p1, independently of each other. the fer ...	1977	410469
[genetic localization of a mutation rendering the growth of e coli k12 insensitive to illumination at 365 nm].	the genotype of the nop mutant recently isolated from the e. coli k 12 strain ab 1157 has been characterized. this mutant lacks 4-thiouridine in its trna and is much less susceptible to near ultraviolet-induced growth delay than wild type cells. this phenotype results from a single mutation called nuv which has been localized on the e. coli genetic map. nuv is found by conjugation to lie between the origins of injection of hfr p4x and hfr cavalli in the vicinity of the lac gene. cotrans-duction ...	1977	408039
genetic analysis of escherichia coli o111:b4, a strain of medical and biochemical interest.	procedures have been worked out which allow, for the first time, the genetic analysis of escherichia coli o111:k58:h2 (o111:b4). the approximate map position of mutant loci was determined by mating with 15 hfr strains of e. coli k-12. in addition, p1 transduction procedures were used for establishing relative gene order and linkage for any region of the e. coli o111:b4 chromosome. to obtain these, it was necessary to select for a rare p1 lysogen since e. coli o111:b4 is resistant to phage p1. fi ...	1977	400785
replication and gene functions of the bacteriocinogenic plasmid clodf13.	the replication and genetic constitution of plasmid clodf13 was studied using mutants of clodf13 obtained by ntg mutagenesis, insertion of the ampicillin transposon tn901, or deletion of particular clodf13 dna regions. analysis of the polypeptides encoded by these mutant plasmids enabled us to locate six genes on the clodf13 physical map. these genes cover about 60% of the coding capacity of clodf13. a large part of the clodf13 genome (about 30%) is involved in the conjugal transfer of this plas ...	1979	394925
escherichia coli mutants incapable of supporting replication of f-like plasmids at high temperature: isolation and characterization of mafa and mafb mutants.	mutants of escherichia coli k-12 defective in replication of f-like plasmids at a high temperature (42 degrees c) were found among threonine-independent (thr+) revertants of a threonine-requiring f' stain after localized mutagenesis with n-methyl-n'-nitro-n-nitrosoguanidine. transduction experiments with phage p1 permitted us to divide these mutations into two classes with respect to man location; some mutations were located between thr and ara at about 0.8 min, very close to maf-1 reported prev ...	1979	391803
isolation and characterization of dnax and dnay temperature-sensitive mutants of escherichia coli.	escherichia coli mutants with temperature-sensitive (ts) mutations in dnax and dnay genes have been isolated. based on transduction by phage p1, dnax and y have been mapped at minutes 10.4--10.5 and 12.1, respectively, in the sequence dnax pure dnay. both dna xts36 and yts10 are recessive to wild-type alleles present on episomes. f13 carries both dnax+ and y+; the shorter f210 carries dnay+, but not x+. lambda tranducing phages that carry dnax+ or y+ have been isolated, and hybrid plasmids of co ...	1979	391641
mapping of a new hem gene in escherichia coli k12.	a new type of haem-deficient mutant was isolated in escherichia coli k12 by neomycin selection. the mutant, designated sasx38, accumulated uroporphyrin, coproporphyrin and protoporphyrin. since it possessed normal ferrochelatase activity, it was assumed to be deficient in protoporphyrinogen oxidase activity. the gene affected in the mutant was designated hemg. mapping of the hemg gene by phage p1-mediated transduction showed that it was located very close to the chlb gene (frequency of cotransdu ...	1979	390093
a new pleiotropic bacteriophage p1 mutation, bof, affecting c1 repression activity, the expression of plasmid incompatibility and the expression of certain constitutive prophage genes.	in bacteriophage p1 an amber mutation in a new gene, bof, has been isolated. the bof-1 phage mutant exhibits a pleiotropic phenotype; bof product is non-essential, and acts as a positive modulator. in p1 bac-1 mutants, in which a dnab analog product, ban, is expressed constitutively, the bof product activates ban expression both in the prophage state and in lytic growth: p1 bof bac prophages have a reduced ban activity and in lytic growth p1 bof bac phages show a lower ban activity than p1 wild ...	1979	386043
a dnab analog ban, specified by bacteriophage p1: genetic and physiological evidence for functional analogy and interactions between the two products.	bacteriophage p1 has been shown previously to determine a product ban that can substitute in dna replication for the protein specified by cis-tron dnab of escherichia coli. however, ban product furnished by p1 bac prophage (ban constitutive) substitutes only poorly for dna replication in the absence of dnab product in a strain bearing an unsuppressed amber mutation, dnab266, as shown by the cryosensitivity of the dnab266 (p1 bac) lysogen and its unability to support lambda growth. an additional ...	1979	386042
rearrangements of genetic material in escherichia coli as observed on the bacteriophage p1 plasmid.		1979	385224
chromosomal location and expression of the structural gene for major outer membrane protein ia of escherichia coli k-12 and of the homologous gene of salmonella typhimurium.	the gene determining the structure of a major outer membrane protein of escherichia coli, protein ia, has been located between serc and pyrd, at the min 21 region of the linkage map. this is based on the isolation and characterization of e. coli-salmonella typhimurium intergeneric hybrids as well as analyses of a mutation (ompf2) affecting the formation of protein ia. when the serc region of the s. typhimurium chromosome was transduced by phage p1 into e. coli, two classes of transductants were ...	1979	378974
non-random distribution of transduction termini in transductants from the integrated r plasmid, r100-1.	tra+ and tra- derivatives of drug resistance plasmid, r100-1, were isolated by phage p1 from an hfr donor with integrated r100-1 and then analyzed by complementation tests with tra- point mutants of flac. tra+ derivatives of r100-1 carrying tetracycline resistance alone and those carrying all six drug-resistrance genes could support transfer of tra- point mutants of flac except flac traj, whereas all of tra- derivatives of r100-1 failed to complement any one of tra- point mutants of flac. this s ...	1979	375027
genetic studies of an escherichia coli k-12 temperature-sensitive mutant defective in membrane protein synthesis.	the mutant dive42(ts) of escherichia coli k-12, defective in the synthesis of membrane proteins and in the transcription of the lac operon at high temperature, has been further characterized. it was found that a mutation (dive42) located at about min 22 on the e. coli chromosome map is responsible for the lac- phenotype and temperature-sensitive growth. the mutation could be contransduced with serc, pyrd, or pyrc by phage p1 at a frequency of 4, 16, or 0.5%, respectively, the gene order being se ...	1979	374381
regulation of nonspecific acid phosphatase in salmonella: phon and phop genes.	mutations in salmonella typhimurium strains lacking nonspecific acid phosphatase mapped in two unlinked loci. one of these, phop, was cotransducible by phage p22 with purb, whereas the second, phon, was cotransducible by phage p1 with pura. mutants with temperature-sensitive nonspecific acid phosphatase activity (measured in whole cells) were also isolated. a phon mutant with thermolabile whole-cell activity was isolated directly from wild-type lt-2. several other mutants with temperature-sensit ...	1979	374361
chloramphenicol resistance mutation in escherichia coli which maps in the major ribosomal protein gene cluster.	localized mutagenesis and selection for streptomycin resistance were utilized to isolate a chloramphenicol resistance mutation in escherichia coli k-12 linked to the stra (rpsl) locus. bacteriophage p1 transduction verified the map position of the new resistance mutation at 72 min, placing it within a dense cluster of ribosomal protein genes. the map position differs from that of known cmla and cmlb mutations, which map at 18 and 21 min, respectively. ribosomes prepared from chloramphenicol-resi ...	1979	374348
mapping of ilvo loci of escherichia coli k-12 with bacteriophage lambda dilv.	a set of lambda dilv phage have been used in a deletion mapping procedure to determine the location of two previously characterized ilvo alleles. in contrast to earlier conclusions derived from three-factor crosses and episome-shortening techniques with phage p1, the order found is ilvg-ilvo-ilveda. a three-factor cross with phage p1 is described that is not consistent with this location for an ilvo allele. further analysis of this particular three-factor cross revealed than an artifact attribut ...	1979	374344
suppression of a thermosensitive dnaa mutation of escherichia coli by bacteriophage p1 and p7.		1978	372960
a model for plasmid maintenance of bacteriophage p1.	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.	1978	371479
chromosomal location of the mop (groe) gene necessary for bacteriophage morphogenesis in escherichia coli.	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.	1978	370345
[regulation of the activity of escherichia coli deo-operon structural genes: the mutation mapped within the operon boundaries and affecting drm and pup gene activity].	the mutant air38 is isolated from escherichia coli k-12 strain deficient in thymidilate synthetase and deoxyriboaldolase (hfrh, thy, dra)--by selection for low thymine requirement on the medium containing inosine as the carbon source. under the conditions mentioned the mutant air38 (thy, dra) grows at low thymine concentration (2 mkg/ml), and is uncapable to grow in the presence of thymidine (40 mkg/ml). dra+ derivatives of the air38 do no catabolize inozine in the presence of thymidine as well. ...	1978	369945
analysis of bacteriophage p1 immunity by using lambda-p1 recombinants constructed in vitro.	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 immuni ...	1978	364485
a second transport system for sn-glycerol-3-phosphate in escherichia coli.	strains containing phage mucts inserted into glpt were isolated as fosfomycin-resistant clones. these mutants did not transport sn-glycerol-3-phosphate, and they lacked glpt, a protein previously shown to be a product of the glpt operon. by plating these mutants on sn-glycerol-3-phosphate at 43 degrees c, we isolated revertants that regained the capacity to grow on g3p. most of these revertants did not map in glpt and did not regain glpt. these revertants exhibited a highly efficient uptake syst ...	1978	363686
acylaminoacid esterase mutants of salmonella typhimurium.	salmonella typhimurium contains three electrophoretically separable enzyme activities that hydrolyze n-acetyl phenylalanine beta-naphthyl ester (napne). one of these enzymes is an endoprotease, protease i. mutations at a locus apea near pure lead to loss of this enzyme. we have found that n-acetyl leucine alpha-naphthyl ester (nalne) is not hydrolyzed by protease i but is a good substrate for the other two activities. using nalne as a chromogenic substrate to screen colonies growing on agar, we ...	1978	360040
salmonella typhimurium mutants lacking protease ii.	mutants of salmonella typhimurium lacking protease ii, an endoprotease with trypsin-like specificity, have been isolated. these mutants can be identified by using the chromogenic substrate n-methyl-n-p-toluenesulfonyl-l-lysine beta-naphthyl ester to screen colonies growing on agar for the presence of the enzyme. all of the mutations isolated map at locus tlp (typsin-like protease) which is cotransducible (approximately 1%) using phage p1 with tre (trehalose utilization) at approximately 58 min o ...	1978	355236
[intergeneric conjugational hybridization of escherichia coli and salmonella typhimurium. 1. obtaining a salmonella hybrid possessing greater recipient activity in crosses with escherichia coli].	intergeneric hybrids were selected from mating hfrh escherichia coli with f- salmonella typhimurium. the hybrid obtained from e. coli leu+ and pro+ genes possessed the increased recipient ability in the mating with e. coli hfrr1 (o--ilv--mete--ara). this hybrid lacked the ability to restrict the phage p1 dna propagated on e. coli k-12. the replacement of mutated uvra gene of salmonella for uvra+ gene of e. coli restore uvr+ phenotype of salmonella mutant.	1977	352802
the biochemical and genetic basis for high frequency thiomethyl galactoside resistance in lambda,lambdadg lysogens of escherichia coli.	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 ...	1978	344832
mechanism of defective lysogenization by phage p1 in a lon-mutant of escherichia coli k-12.	phage p1 cannot lysogenize a lon- mutant of escherichia coli k-12, which is defective in the regulation of cellular division cycle to result in snake formation (14). p1 mutants, called p1pla, can lysogenize the lon- host. these mutations have been classified into two complementation groups: one is cis-dominant; the other is trans-dominant. a temperature-sensitive lon- mutant was isolated, which exhibited the lon- phenotype at 42 c but not at 33 c. a temperature-shift experiment of the p1-lysogen ...	1977	339037
in vitro packaging of a lambda dam vector containing ecori dna fragments of escherichia coli and phage p1.	in this report we describe a coliphage lambda vector system for cloning endo r. ecori dna fragments. this system differs significantly from those previously described in two ways. first, restricted and ligated dna is encapsidated in vitro. second, with increasing lambda dna size in the range 78 to 100% that of wild-type, the efficiency of dna encapsidation into infectious phage particles markedly increases. for lambda wild-type dna the efficiency of in vitro packaging (10(6) to 10(7) plaques pro ...	1977	338419
the frequency of p1 transduction of the genes of escherichia coli as a function of chromosomal position: preferential transduction of the origin of replication.	the frequencies with which the generalized transducing phage p1 transduced 26 selected markers on the e. coli. chromosome were measured. the frequencies were found to vary relative to argh+ = 1 from a maximum of 6.8 near the origin of replication to a minimum of 0.23 for a marker not far from the terminus. the low frequencies obtained for some markers were shown not to result from poor expression under the selective conditions employed. when plotted as a function of marker position on the chromo ...	1977	337128
naturally occurring plasmid carrying genes for enterotoxin production and drug resistance.	escherichia coli strain 86, isolated from a piglet with diarrhea, carries plasmid-linked genes for resistance to tetracycline, streptomycin, and sulfonamides and for production of heat-labile and heat-stable enterotoxin. results of (i) genetic experiments involving conjugal transfer and phage p1-mediated transduction and (ii) physical experiments involving electron microscopic examination of plasmid dna and heteroduplex analysis show that a single conjugative plasmid carries the genes for drug r ...	1977	333581
recombinant plasmid that carries part of the nitrogen fixation (nif) gene cluster of klebsiella pneumoniae.	we have cloned fragments of the klebsiella pneumoniae genome that carry part of the his operon and part of the nitrogen fixation (nif) gene cluster on the amplifiable plasmid pmb9. one particular plasmid, pcra37, complements mutations in the hisd, nifb, and niff loci. the physical map of pcra37 as determined by restriction enzyme analysis correlates with the genetic map of the his-nif region as determined previously by phage p1-mediated cotransductional analysis.	1977	331321
maintenance of bacteriophage p1 plasmid.	three mutants of bacteriophage p1 affected in their ability to maintain the lysogenic state stably are described here. these mutants were normal in lytic growth, but lysogenic derivatives segregated nonlysogens at abnormally high rates (1 to 30% per division). cells harboring these mutant prophages were elongated or filamentous. the mutations responsible for this prophage instability fell into two classes on the bases of their genetic location, their effect on the ability to lysogenize reca bact ...	1977	330876
effects of mutations in the immunity system of bacteriophage p1.	a mutant of bacteriophage p1 that made an altered c1 repressor is described. the mutant c1 product had two configurations: in lysogens, at high temperatures, it permitted constitutive expression of the normally repressed dna replication function ban and was insensitive to the action of ant, a product expressed by the virulent mutant p1virs and by the heteroimmune phage p7 (formerly phiamp+) and normally able to overcome c1 repression; in mutant lysogens at low temperatures, the mutant repressor ...	1977	330875
growth of bacteriophage p1 in recombination-deficient hosts of escherichia coli.		1977	329556
fine-structure mapping and complementation analysis of the escherichia coli cysb gene.	sixty-two point mutations were isolated in escherichia coli by means of transduction with mutagenized phage p1. twenty-two deletions extending into cysb but able to recombine with at least some of the point mutations were isolated on a transmissible e. coli plasmid. mapping of the point mutations against the deletions divided the former into 16 deletion groups. nine merodiploids were constructed in which the chromosome carried one of the three point mutations most distal to the trp operon and in ...	1977	326769
menaquinone biosynthesis: mutants of escherichia coli k-12 requiring 2-succinylbenzoate.	two independent mutants of escherichia coli k-12, selected for their inability to grow anaerobically with fumarate as the terminal electron acceptor, were shown to be deficient in menaquinone biosynthesis. in both cases, exogenously supplied 2-succinylbenzoate promoted normal anaerobic growth on a lactate plus fumarate medium. anaerobic growth of the mutants on glucose minimal medium was impaired but could be restored to normal by adding either uracil or 2-succinylbenzoate. the addition of 2-suc ...	1977	324971
multiple physical differences in the genome structure of functionally related bacteriophages p1 and p7.	comparative restriction cleavage analysis of the genomes of bacteriophage p7, of several recombinant phages between p7 and p1, and of bacteriophage p1 allowed to draw psti, bg/ii, bamhi and hindiii cleavage maps of all genomes studied. the data obtained complement yun and vapnek's (1977) conclusions with regard to areas of major nonhomology based on electron microscopical heteroduplex analysis and they identify several additional minor differences between p1 and p7. the use of hybrid phage strai ...	1979	289897
genetic control of glutamine synthetase in klebiella aerogenes.	mutations at two sites, glna and glnb, of the klebsiella aerogenes chromosome result in the loss of glutamine synthetase. the locations of these sites on the chromosome were established by complementation by episomes of escherichia coli and by determination of their linkage to other genetic sites by transduction with phage p1. the glnb gene is located at a position corresponding to 48 min on the taylor map of the e. coli chromosome; it is linked to trya, nadb, and gua. the glna gene is at a posi ...	1975	234939
an escherichia coli mutant defective in single-strand binding protein is defective in dna replication.	an escherichia coli mutant, temperature-sensitive for dna synthesis in vivo and in vitro, is defective in single-strand binding protein (ssb; dna-binding protein). conversion of phage g4 single strands to the duplex form is defective in crude enzyme fractions of the mutant and is complemented by pure wild-type ssb. radioimmunoassays of mutant extracts show normal levels of material crossreacting with anti-ssb antibody. ssb purified to homogeneity from the mutant is active, with lower specific ac ...	1979	221903
a gal region mutant that requires camp for growth on galactose in an adenyl cyclase negative (cya delta) background.	strains of escherichia coli k12 that contain a deletion of the adenyl cyclase gen (cya delta), required for the synthesis of cyclic adenosine-3';5' monophosphate (camp), grow on galactose-containing minimal medium. a mutant was isolated that grows on this medium only if camp is added. the mutation (designated galp20) is linked to the gal operon region as determined by both generalized transduction with bacteriophage p1 and specialized transduction with bacteriophage lambda. studies with galp20 c ...	1977	190530
epstein-barr virus latency and bacteriophage p1 lysogeny-possible analogies.		1975	183687
regulatory circuits in bacteriophage p1 as analyzed by physical dissection and reconstruction.		1979	161219
cloning and physical mapping of the dnaa region of the escherichia coli chromosome.	the dnaa gene of escherichia coli k-12, supposedly present in the deoxyribonucleic acid (dna) of specialized transducing phase lambda i21 dnaa-2, was cloned onto plasmid pbr322. the new plasmid was named pmcr501. physical analyses of dnas of lambda i21 dnaa-2 and pmcr501 revealed the following. the lambda i21 dnaa-2 dna retained the delta sr i lambda 1-2 and ninr5 deletions and imm21 substitution which were originally present in the parental phage. the size reduction was compensated for by the i ...	1979	160412
a dnab-analog dna-replication protein of phage p1.		1979	157840
escherichia coli mutants deficient in deoxyuridine triphosphatase.	mutants deficient in deoxyuridine triphosphatase (dutpase) were identified by enzyme assays of randomly chosen heavily mutagenized clones. five mutants of independent origin were obtained. one mutant produced a thermolabile enzyme, and it was presumed to have a mutation in the structural gene for dutpase, designated dut. the most deficient mutant had the following associated phenotypes: less than 1% of parental dutpase activity, prolonged generation time, increased sensitivity to 5'-fluorodeoxyu ...	1978	148458
sucrose-dependent spectinomycin-resistant mutants of escherichia coli.	spectinomycin-resistant (spcr) mutants of escherichia coli were isolated from nutrient agar plates containing 20% sucrose and 100 mug of spectinomycin per ml. about one-third of the spcr mutants thus obtained were sucrose dependent (sucd) and were classified into two types: i, those unable to grow on sucrose-free medium in the presence of spectinomycin; and ii, those unable to grow on sucrose-free medium irrespective of the presence of spectinomycin. most of these mutants were hypersensitive to ...	1976	128550
altered phospholipid composition in mutants of escherichia coli sensitive or resistant to organic solvents.	mutants of escherichia coli with altered resistance to low molecular weight organic solvents were isolated. solvent-resistant mutants showed a decrease in the ratio of phosphatidylethanolamine to the anionic phospholipids (phosphatidylglycerol and cardiolipin) relative to the wild-type, whereas solvent-sensitive strains showed an increase. reversion studies on representative mutants demonstrated that the phenotypic response to solvents and the changes in phospholipid composition were genetically ...	1979	92527
sh. dysenteriae serotypes2,4,8-immunochemistry and phage receptor activity.	among three analyzed serotypes of shigella dysenteriae, namely, the serotypes 2,4 and 8, the serotype 2 proved to be a strong immunogen in rabbits, inducing anti-polysaccharide antibodies as well as antiprotein antibodies in all the animals. in contrast, the serotypes 4 and 8 were weak immunogens and among the rabbits some have synthesized only anti-proteins while others had antibodies against the somatic conjugate. aside from the somatic antigens, large amounts of proteins were isolated from al ...	1976	63197
ultrastructural localization of viral antigens using the unlabeled antibody-enzyme method.	employing the unlabeled antibody enzyme method at the ultrastructural level, a comparison was made between preembedding staining and postembedding staining for the detection of viral antigens. the bacteriophage p1 absorbed to the surface of shigella dysenteriae was used as a model system. preembedding staining resulted in the specific deposition of peroxidase-antiperoxidase (pap) complexes as an electron-dense coating around the viral heads. disadvantages of the preembedding staining method incl ...	1976	57192
deletion mapping of the pola-metb region of the escherichia coli chromosome.	a lambdaci857 prophage inserted into one of the genes of the rha locus was used to select deletions unambiguously ordering the markers pola-glna-rha-pfka-tpi-metbjf. transduction with phage p1 indicates at least 70% linkage between glna and pola. the order of the pfk and tpi markers is reversed from that previously published. despite the relatively large distance separating the glna and rha loci, deletions removing this entire region have no obvious phenotype. the isolation of tn10 transposons i ...	1979	35528
regulation of glutamine synthetase formation in escherichia coli: characterization of mutants lacking the uridylyltransferase.	a lambda phage (lambdank55) carrying the translocatable element tn10, conferring tetracycline resistance (tetr), has been utilized to isolate glutamine auxotrophs of escherichia coli k-12. such strains lack uridylyltransferase as a result of an insertion of the tn10 element in the glnd gene. the glnd::tn10 insertion has been mapped at min 4 on the e. coli chromosome and 98% contransducible by phage p1 with dapd. a lambda transducing phage carrying the glnd gene has been identified. a glnd::tn10 ...	1978	26660
glutamine synthetase of klebsiella aerogenes: properties of glnd mutants lacking uridylyltransferase.	the glnd mutation of klebsiella aerogenes is cotransducible by phage p1 with pan (requirement for pantothenate) and leads to a loss of uridylytransferase and uridylyl-removing enzyme, components of the glutamine synthetase adenylylation system. this defect results in an inability to deadenylylate glutamine synthetase rapidly and in a requirement for glutamine for normal growth. suppression of the glnd mutation are located at the glutamine synthetase structural gene glna.	1978	26659
lack of a regulatory function for glutamine synthetase protein in the synthesis of glutamate dehydrogenase and nitrite reductase in escherichia coli k12.	synthesis of glutamine synthetase (gs) in anaerobic batch cultures of escherichia coli was repressed when excess nh4+ was available, but derepressed during growth with a poor nitrogen source. in wild-type bacteria there was only a weak inverse correlation between the activities of gs and glutamate dehydrogenase (gdh) during growth in various media. no positive correlations were found between the activities of gs and nitrite reductase, or between gs and cytochrome c552: both of these proteins wer ...	1977	16079
transduction of chromosomal genes between enteric bacteria by bacteriophage p1.	we have used p1 transduction to create intergeneric hybrid strains of enteric bacteria by moving the gena and hut genes between klebsiella aerogenes, escherichia coli and salmonella typhimurium. the use of e. coli as the recipient in such transductions permits the construction of episomes and specialized transducing phage containing non-e. coli material. the effect of host restriction modification and deoxyribonucleic acid homology on the frequency of intergeneric transduction of these loci has ...	1976	3494