| bacteriophage x-2: a filamentous phage lysing incx-plasmid-harbouring bacterial strains. | phage x-2, a filamentous rod about 950 nm in length, was isolated from sewage as plating on strains of escherichia coli, salmonella typhimurium or serratia marcescens carrying either the incx plasmid r6k, or the unique plasmid r775. phage x-2 differs morphologically from a previously described very broad host range filamentous phage x which also lyses plasmid r6k-carrying strains and the phages differ in their resistance to inactivation by diethyl ether. phage x-2 is serologically unrelated to p ... | 1988 | 3076188 |
| method of obtaining plaque-forming phage x of shigella flexneri. | | 1972 | 4621297 |
| preliminary studies on the influence of the composition of the culture medium and incubation temperature on propagation of shigella flexneri phage x. | | 1971 | 4938009 |
| phage x: a plasmid-dependent, broad host range, filamentous bacterial virus. | phage x was isolated from sewage as plating on escherichia coli or salmonella typhimurium strains harbouring the incompatibility group x plasmid r6k. it also plated on a strain of serratia marcescens carrying this plasmid. it failed to form plaques on proteus mirabilis, p. morganii or providencia alcalifaciens harbouring r6k, but did multiply on them. no phage increase occurred with homologous r- strains. phage x also plated or registered an increase in titre on e. coli or s. typhimurium strains ... | 1981 | 6121839 |
| inci2 plasmids specify sensitivity to filamentous bacteriophage ike. | bacterial strains carrying the derepressed incompatibility group inci2 plasmids tp114drp-l or r721pilc were lysed by the filamentous bacteriophages ike, i2-2, and x. phage i2-2 was serologically related to ike, but phage x was not. phage ike adsorbed to the tips of thick pili determined by the inci2 plasmids, but not to the well-known thin i2 pili. | 1983 | 6131882 |
| cloning and sequencing of the glucosyl transferase-encoding gene from converting bacteriophage x (sfx) of shigella flexneri. | shigella flexneri type y strains (-;3,4) are converted to type x (-;7,8) by bacteriophage x (sfx) that causes glucosylation of the o-antigenic polysaccharide chain. the gene (gtr) encoding glucosyl transferase from bacteriophage x has been cloned and sequenced. the protein encoded by gtr consists of 416 amino acids with a m(r) of 47,369. the cloned gtr product was able to convert a s. flexneri strain type y (sfl 124, a live attenuated candidate vaccine strain) to type x. the importance of the hy ... | 1993 | 8335266 |
| immunogenicity of the shigella flexneri serotype y (sfl 124) vaccine strain expressing cloned glucosyl transferase gene of converting bacteriophage sfx. | the glucosyl transferase gene (gtr) from bacteriophage phage x (sfx) caused partial conversion of serotype y (group antigen 3, 4) to x (group antigen 7, 8) when introduced into a candidate vaccine strain of shigella flexneri serotype y (sfl124). the gtr gene caused conversion of o-antigens but did not eliminate the adsorption of the corresponding phage sfx. the hybrid strain expressing both group antigens 7, 8 and 3, 4 showed 75% protection when immunized guinea pigs were challenged with a wild- ... | 1995 | 8569531 |
| genes involved in conjugative dna processing of plasmid r6k. | the conjugative transfer region of the incx plasmid r6k (tra(x)) was analysed by transposon mutagenesis and dna sequencing. tn5tac1 insertional mutations localized tra(x) to a 14.8 kb segment containing the alpha origin of transfer (orit alpha), genes involved in conjugative dna-processing (dtr(x)) and genes involved in pilus synthesis and assembly (mpf(x)). a second functional orit, oritbeta, was located at a distance of 5.3 kb from orit alpha and was outside tra(x). mpf(x) occupied a segment o ... | 1997 | 9218765 |
| mechanism of bacteriophage sfii-mediated serotype conversion in shigella flexneri. | we have isolated the lysogenic bacteriophage sfii, which mediates glucosylation of shigella flexneri o-antigen, resulting in expression of the type ii antigen. sfii belongs to group a of the bradley classification and has a genome size of 42.3kb. dna sequencing of a 4 kb bamhi subclone identified four open reading frames (orfs), of which only two were found to be necessary for serotype conversion. these genes were named bgt, which encodes a putative bactoprenol glucosyl transferase, and gtrii, e ... | 1997 | 9426131 |
| serotype conversion of a shigella flexneri candidate vaccine strain via a novel site-specific chromosome-integration system. | shigella flexneri sfl124 (serotype y) is a promising live oral vaccine candidate, which has been shown to be safe and immunogenic in human volunteers. to change the serotype of this vaccine strain, we inserted a serotype conversion gene cluster into the chromosome of sfl124 by using a bacteriophage-based site-specific integration system. by cloning an integrase gene (int), an attachment site (attp) and a glucosyl transfer gene cluster from bacteriophage sfx into a suicide vector, and subsequentl ... | 1998 | 9741086 |
| functional analysis of the o antigen glucosylation gene cluster of shigella flexneri bacteriophage sfx. | previous studies have shown that shigella flexneri bacteriophage x (sfx) encodes a glucosyltransferase (gtrx, formerly gtr), which is involved in o antigen modification (serotype y to serotype x). however, gtrx alone can only mediate a partial conversion. more recently, a three-gene cluster has been identified next to the attachment site in the genome of two other s. flexneri bacteriophages (i.e. sfv and sfii). this gene cluster was postulated to be responsible for a full o antigen conversion. h ... | 1999 | 10376843 |
| progressive loss of lambda prophage recombinogenicity in uv-irradiated escherichia coli: the role of recbcd enzyme. | recbcd enzyme is involved in the radiation-induced process known as prophage inactivation. the process leads to the inability of lambda prophage to excise itself from the escherichia coli chromosome via site-specific recombination. in this work we sought to further characterize the role of recbcd enzyme in this process. in addition, we examined the ability of irradiated prophage to recombine with the infecting homologous phage. we used several e. coli mutants differentially altered in recbcd's a ... | 2000 | 11130863 |
| the structure of the dna of bacteriophage x-174. iv. pyrimidine sequences. | | 1963 | 13952102 |