Detection of a protein, similar to the sex pilus subunit, in the outer membrane of Escherichia coli cells carrying a derepressed F-like R factor

Self Cite

Two derivatives of the F-like R factor R1drd19 carrying mutually exclusive resistance determinants were used to study the role of the mucopeptide in the expression of conjugal functions. The use of metabolically active penicillin spheroplasts in R+ times R- matings had no effect on the ability of the cells to donate or accept a plasmid. However, in R+ times R+ matings it was found that surface exclusion was totally abolished if the donor, but not the recipient, was a spheroplast. This result implies that the traS gene, expressed by the excluding plasmid, is dependent for its action on an intact mucopeptide layer in the donor cell, and that this interaction is independent of the transfer ability of the excluding plasmid.

Section: Resultssupporting

confidence: 75%

“…Bacterial strains and R factors. Bacterial strains UB1005 and UB1025, and R factors Rldrdl9.Kl and Rldrdl9.K-1 (derivatives of Rldrdl9 that carry mutually exclusive resistance determinants), have been described previously (3).…”

Section: Methodsmentioning

confidence: 99%

Role of the cell surface in bacterial mating: requirement for intact mucopeptide in donors for the expression of surface exclusion in R+ strains of Escherichia coli

Beard¹,

Bishop²

1975

Self Cite

“…Our observations indicate that it only takes 10 s for a pilus to disappear (retract) at 500C, and it is possible that they retract as fast in the presence of cyanide (13). The pilus might dissociate into subunits (pilin) as it retracts (11), and these subunits might enter the pool of pilin that is probably located in the outer membrane (1,14). The dissociation of a pilus at its base in the membrane could be spontaneous, or it might require an enzyme.…”

Section: Discussionmentioning

confidence: 80%

Effects of high temperature on Escherichia coli F pili

Novotny¹,

Fives-Taylor²

1978

The effects of high temperatures (46 to 5000) on the production of F pili by Escherichia coli were studied by electron microscopy. Attached F pili rapidly disappeared at 48 and 500C but not at 460C. Free pili were not denatured at these temperatures. The pili that disappeared from the cells at 500C did not appear as free pili in the culture supematant fluid, indicating that the pili had retracted to the cell surface or into the cell. The adsorption of either R17 phage or F pili antibody to the sides of pili prevented retraction. The disappearance of pili was accompanied by a loss in the ability to adsorb R17 phage but not M13 phage, suggesting that the tip of a pilus remains exposed after retraction.F pili rapidly disappear from the surface of donor strains of Escherichia coli K-12 under certain conditions. These conditions include infection with filamentous, donor-specific phages (9,11); incubation in the presence of sodium cyanide (13) and arsenate (17); and temperature shifts from 37 and 250C (14). Marvin and Hohn (11) were the first to suggest that F pili could retract. They observed that F pili disappeared during Ff phage infection and suggested that the pili retract into the cell with the phage on their tips. Other types of pili may also retract. The production of I pili by E. coli cells is stimulated by I pili antibody, and it was suggested that antibody might cause an increase in attached pill by preventing retraction (10). The shortening of Pseudomonas aeruginbsa pffi after adsorption of RNA phage to the sides suggests that they retract to the point of attachment of the phage (2). Novotny and Fives-Taylor (13) suggested that the disappearance of F pili in the presence of cyanide and at certain temperatures was due to retraction and presented a dynamic model for the growth of pili that supposes that F pili elongate and retract continuously and that the number of F pili per cell and the average length of pili reflect the state of equilibrium between these two processes.Studies of the outgrowth of F pili indicate that outgrowth requires the synthesis of ATP (16, 17) and the synthesis of RNA (8). The synthesis of DNA (16) or the synthesis of protein (3, 16) is not required. Although the synthesis of DNA is not needed for the reappearance of pili, there is evidence that DNA may be involved (7,8).Very little is known about the requirements for retraction. Retraction does not require the synthesis of ATP because pili retract in the presence of energy poisons (13, 17), and it does not require the synthesis of RNA and protein because rifampin, streptolydigin, and chloramphenicol have no immediate effect on retraction in the presence of cyanide (8). Retraction is inhibited by chloramphenicol after 15 min, suggesting that retraction requires a protein whose pool size is limited (8).Retraction and outgrowth are both sensitive to temperature. The sudden decrease in the number of attached F pili that occurs when cells are cooled from 37 to 250C (14) suggests that outgrowth, but not retraction, is inhibited at 250C. ...

“…Rldrd-19, which only mediates resistance to kanamycin (4). From the EcoRI digest pattem it was shown that many fragments have been deleted, and on comparing the pattern with the map of plasmid Rldrd-19 (7) it is clear that the deletion covers all of the r-determinant except for the fragments F (the kanamycin resistance fragment) and J (Fig.…”

Section: Resultsmentioning

confidence: 95%

Clustering of genes involved in replication, copy number control, incompatibility, and stable maintenance of the resistance plasmid R1drd-19

Molin¹,

Stougaard²,

Uhlin³

et al. 1979

Plasmid R1drd-19 is present in a small number of copies per cell of Escherichia coli. The plasmid was reduced in size by in vivo as well as in vitro (cloning) techniques, resulting in a series of plasmid derivatives of different molecular weight. All plasmids isolated contain a small region (about 2 x 10(6) daltons of deoxyribonucleic acid) of the resistance transfer factor part of the plasmid located close to one of the IS1 sequences that separates the resistance transfer factor part from the resistance determinant. All these derivatives were present at the same copy number, retained the incompatibility properties of plasmid R1drd-19, and were stably maintained during cell division. Genes mutated to yield copy mutations also were found to be located in the same region.