| an inverted repeat sequence of the incfi plasmid colv2-k94 increases multimerization-mediated plasmid instability. | a detailed physical map of the region of the incfi plasmid colv2-k94 containing the rep1 replicon, a tn903 transposon, and an inverted repeat structure (x1) with unknown properties was prepared by cloning restriction fragments into pbr325. inserts carrying the 1.2 kb repeated sequence of x1, but not the is903 sequence of tn903, had a destabilizing effect on pbr325 and pbr322 plasmid maintenance. one of these derivatives, pws139, was studied further and was shown to have elevated levels of multim ... | 1986 | 3531398 |
| fino sequences on conjugally repressed and derepressed f-like plasmids. | dna-dna hybridization studies have demonstrated the physical relatedness of the fertility inhibition gene, fino, among both fino+ and fino- f-like conjugative plasmids, viz. colv2-k94, r100-1,r1drd19,r1,r6-5, ucr123, r386, p307, r453, r773, and pip162-1. furthermore, the data indicate that fino sequences on the fino- plasmid colv2-k94 map downstream of the transfer region, within 93.6-95.3 colv2-k94. | 1987 | 3306734 |
| characterization of the stability functions and inverted repeat structure x3 of the incfi plasmid colv2-k94. | a region of the incfi plasmid colv2-k94 which showed homology to the sop partitioning genes of f was cloned and characterized in an attempt to study the stability functions of this element. the sop region contained the incd incompatibility determinant common to many incfi plasmids, but could not confer on colv2-k94 miniplasmids the same stable inheritance found in the intact colv2-k94; thus, other functions appear to be required for efficient plasmid maintenance. adjacent to the area of sop homo ... | 1986 | 3024792 |
| a physical and genetic map of the incfi plasmid colv2-k94. | a restriction enzyme map of the incfi plasmid colv2-k94 was generated using ecori, bamhi, hindiii, and xhoi; the genetic features of this element were then mapped from previous heteroduplex studies. | 1985 | 2988000 |
| cloning and dna sequence of plasmid determinant iss, coding for increased serum survival and surface exclusion, which has homology with lambda dna. | escherichia coli k12 cells carrying a cloned 1.4 kb hindiii fragment from plasmid colv2-k94, showed increased survival in guinea pig serum. the recombinant plasmid also conferred group ii surface exclusion, i.e. the cells were reduced in recipient ability towards the incoming plasmid r538drd in conjugation experiments. southern blotting suggested homology with bacteriophage lambda dna and to the insertion element is2. determination of the dna sequence of the fragment demonstrated the presence of ... | 1989 | 2546040 |
| incompatibility repressor in a repa-like replicon of the incfi plasmid colv2-k94. | the replication region rep1 of the incfi plasmid colv2-k94 was cloned on self-replicating restriction fragments. rep1 was structurally and functionally homologous to the repa replicon of incfii r plasmids. despite this close relationship, these two replication systems were compatible with each other. the nucleotide sequence of the copa incompatibility-replication control gene of rep1 was determined and compared with the copa sequence of repa. six base changes were found in a 24-base-pair span of ... | 1986 | 2423502 |
| comparison of the copb systems of plasmids r1 and colv2-k94: a single base alteration in copb gene is responsible for the increased copy number of the low copy number plasmid colv2-k94. | we have isolated a deletion mutation and a point mutation in the copb gene of the replication region repl of the incfi plasmid colv2-k94. subsequently, this copb gene with and without point mutation was cloned and sequenced, and the point mutation was mapped in the coding region of copb with a change of one amino acid from arginine to serine. furthermore, this copb mutant had an approximately 10-fold increase in copy number. the copb-phenotype of colv2-k94 could be complemented in trans by the c ... | 1990 | 2325626 |
| a bacterial virulence determinant encoded by lysogenic coliphage lambda. | although phage lambda represents a well studied biological systems, it has certain features that remain obscure. among these is the function of the roughly one third of the phage genome dispensable for growth in the laboratory, yet retained despite undoubted pressure to economize. here we report that these 'accessory' sequences contain two genes which are expressed during lysogeny, and encode host-cell envelope proteins. one of these is lom, the product of which is found in the bacterial outer m ... | 1990 | 2144037 |