Publications

direction of deoxyribonucleic acid transfer and replication in a derivative of plasmid r100-1.	the site of integration and the molecular orientation of a prophage mu integrated within the resistance transfer factor component of plasmid r100-1 have been determined on the physical map of the plasmid. this allowed us (i) to determine the direction of deoxyribonucleic acid transfer from orit during conjugation and (ii) to demonstrate the unidirectionality of replication in conditions of exponential growth (by determining the strand preference of mu-specific okazaki fragments).	1979	391800
effects of antibiotic resistance plasmids on the bactericidal activity of normal rabbit serum.	the ability of normal rabbit serum to kill escherichia coli j6-2 was measured. with the concentration of serum adjusted so that approximately 2% of the cells survived after 2 h of incubation, there was no killing of the same strain bearing the f-like plasmid r100. other f-like plasmids also provided the host strain with resistance to serum bactericidal activity, whereas none of the i-like plasmids used provided the host strain with resistance. when e. coli j6-2 bore both r100 and an i-like plasm ...	1978	346487
properties of lambda transducing bacteriophages carrying r100 plasmid dna: mercury resistance genes.	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, c ...	1978	363687
identification of a membrane protein associated with expression of the surface exclusion region of the f transfer operon.	membrane preparations from radioactively labeled male and female strains of escherichia coli k-12 were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and autoradiography. an intensely labeled band corresponding to a protein of molecular weight of 24,000 was readily apparent in preparations from hfr and f-prime strains but not in those from female strains. when preparations from a series of hfr strains containing transfer operon deletions were examined, presence of the band ...	1977	321436
suppression of an escherichia coli dnaa mutation by the integrated r factor r100.1: generation of small plasmids after integration.	we have observed that integration of the r plasmid r100.1 into the chromosome of escherichia coli is associated with the formation of small, covalently closed circular elements. contour length measurements, partial denaturation mapping, and analysis of the deoxyribonucleic acid fragments produced by digestion of one of these, plc1, with the restriction endonuclease ecori indicate that it is the r-determinant element of r100.1.	1977	323231
suppression of an escherichia coli dnaa mutation by the integrated r factor r100.1: origin of chromosome replication during exponential growth.	we have investigated the behavior, during exponential growth, of strains of escherichia coli carrying a dnaa(ts) mutation that has been suppressed by the integration of the f-like r plasmid r100.1. we present evidence showing that replication in these strains proceeds largely from the normal chromosome origin at 30 degrees c, a permissive temperature for the dnaa(ts) gene product, whereas, at 42 degrees c, replication proceeds largely from the integrated plasmid. these conclusions are based on m ...	1977	328481
origin and direction of replication of the drug resistance plasmid r100.1 and of a resistance transfer factor derivative in synchronized cultures.	the origin and direction of replication of the resistance plasmid r100.1 and its resistance transfer factor derivative, par132, were studied by electron microscopy autoradiography of partially denatured molecules and partial denaturation mapping of replicative intermediates. results of these studies indicate the existence of an origin of replication at 8.8 kilobases on the r100 map. replication from this origin in cultures synchronized for initiation of replication is predominantly unidirectiona ...	1977	330504
involvement of is1 in the dissociation of the r-determinant and rtf components of the plasmid r100.1.	the formation of the r-determinant plc1 and of the rtf par132 from the composite plasmid r100.1 was investigated. the general location of is1 sequences on the three plasmids was established by hybridization of lambdar14 cii::is1 dna to ecori generated fragments of the various plasmids separated by agarose gel electrophoresis and transferred directly to nitrocellulose filters. the position of is1 sequences on these fragments and the homologies between fragments were analyzed by electron microscop ...	1977	331072
plasmid-mediated resistance to the bactericidal effects of normal rabbit serum.	an escherichia coli k-12 strain bearing the plasmids r1 or r100 was more resistant to the bactericidal activity of normal rabbit serum than was the same strain without a plasmid. when the plasmid r100 was transferred to several k-12 strains, the strains acquired resistance to serum bactericidal activity.	1976	786896
plasmid incompatibility and control of replication: copy mutants of the r-factor r1 in escherichia coli k-12.	plasmid incompatibility was studied in escherichia coli k-12. by double-antibiotic selection, clones were constructed that carried the two r-factors r1 and r100, both belonging to the compatibility group fii. after release of the selection pressure, each of the two plasmids was lost at the same rate (8% per generation). mutants of r-factor r1 showing an increased number of copies per chromosome (copy mutants) were tested for their incompatibility towards r-factor r100. the results indicate that ...	1975	1102525
transience of the donor state in an escherichia coli k12 strain carrying a repressed r factor.	de-repression of the plasmid r100 in escherichia coli is essentially a transient phenomenon resulting in the transfer of several r factors to different recipient cells from a single donor cell.	1975	1102925
genetic loci responsible for incompatibility on a co-integrate plasmid, r100-1.	an r plasmid, r100-1, was mapped previously (yoshikawa, 1974) by transduction from an integratively suppressed hfr strain to a recipient with a mutation in gene dnaa. by this method various types of transductants of plasmid r100-1 that exist autonomously or in the integrated state were obtained. seventy-one such transductants were used in the present study to map gene inc, which is responsible for incompatibility. the results obtained can be explained by either of the following: (i) r100-1 has o ...	1975	1104570
[incompatible gene (inc) of plasmid r100-1].		1975	1240267
inhibition of flac transfer by the fin+ i-like plasmid r62.	flac mutants have been isolated in escherichia coli k-12 which carry dominant mutations resulting in insensitivity to transfer inhibition by the fin(+) i-like plasmid r62. these mutants were still sensitive to transfer inhibition by the fin(+) f-like plasmid r100 and, conversely, flactrao(-) and trap(-) mutants, which are insensitive to r100 inhibition, were still sensitive to r62. the sites of action of the two inhibition systems are therefore different. furthermore, inhibition by r62, unlike r ...	1974	4370730