Evidence for Two States of F Pili

Wendt, Louis; Mobach, Helen Wedel

doi:10.1128/jb.97.2.640-646.1969

Cited by 4 publications

(1 citation statement)

References 21 publications

(20 reference statements)

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“…In addition, the assay does not detect small pili-phage complexes that pass through filters (26), and there are some conditions where pili no longer bind phage so the assay cannot be used at all. For example, the addition of phenethyl alcohol to a culture prevents phage adsorption to attached pili but not to free pili (27). However, the virtues of phage filtration seem to outweigh its limitations, and the assay is widely used.…”

Section: Discussionmentioning

confidence: 99%

Some Effects of Temperature on the Growth of F Pili

Novotny

Lavin

1971

J Bacteriol

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The effect of temperature on the production of F pili by an F + strain of Escherichia coli B/r was studied by electron microscopy and by a technique involving serum-blocking power. The latter method is based on the ability of F pili to adsorb F pili antibody which inhibits male-specific phage infection. The total amount of pili in a sample was estimated by serum-blocking power; the length of F pili and number per cell was determined by electron microscopy. Cell extracts prepared by sonic oscillation lacked serum-blocking power, suggesting that F pili are not present in the cytoplasm. The number of F pili per cell varied with the growth temperature, but the average length of F pili remained constant. Maximum number of pili per cell occurs between 37 and 42 C; below 37 C the number decreases, reaching zero at about 25 C. When cells are grown at 37 C, blended, and resuspended in fresh media at 25 C, they make F pili. These pili are probably assembled from a pool of subunits that were synthesized during growth at 37 C. The rates of assembly at 25 and 37 C, as judged by the rate of increase in length of F pili, are similar. When cells were grown at 25 C and shifted up to 37 C, there was a 30-min lag in pili production followed by a period of rapid outgrowth. When cells were shifted down from 37 to 20 C, outgrowth (assembly) of pili ceased, and approximately 50% of the attached pili were released in 2 min. No release was observed when cells were shifted to 0 C. This suggests that pili may be released from the cell by a mechanism that requires metabolic activity, but not the outgrowth of F pili.

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Section: Discussionmentioning

confidence: 99%

Some Effects of Temperature on the Growth of F Pili

Novotny

Lavin

1971

J Bacteriol

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Genetics of the F Sex Factor in Enterobacteriaceae

Achtman

1973

Current Topics in Microbiology and Immunology

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F and Type 1 Piliation of Escherichia coli

Biebricher

DÜker

1984

Microbiology

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F and type 1 piliation of various Escherichia coli K12 Hfr and F + strains was re-examined by using a new visualization assay. In anaerobic cultures in rich media, bacteria were well F piliated throughout all growth phases. In aerobic cultures in rich media, F piliation reached a maximum in the mid-exponential phase. The yield of pili was up to 15 mg 1 -l . In aerated cultures, F pili disappeared in the late exponential phase. In rich media F pili were on average 10-20 pm long; in synthetic media they were an order of magnitude shorter, and less numerous. Addition of metabolic poisons (NaCN, NaN,, Na3As0,, phenylethyl alcohol) and starving the bacteria caused rapid disappearance of F pili under aerobic conditions, but had no influence on F piliation under anaerobic conditions. Type 1 piliation was not influenced by these drugs or by an alteration of growth conditions.

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Evidence for Two States of F Pili

Cited by 4 publications

References 21 publications

Some Effects of Temperature on the Growth of F Pili

Some Effects of Temperature on the Growth of F Pili

Genetics of the F Sex Factor in Enterobacteriaceae

F and Type 1 Piliation of Escherichia coli

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