F and Type 1 Piliation of Escherichia coli

Abstract

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.

Tra Proteins Characteristic of F-Like Type IV Secretion Systems Constitute an Interaction Group by Yeast Two-Hybrid Analysis

“…(The numbers of F pili per cell and F-pilus length distribution could amount to the same thing, since factors leading to shorter F pili might favor filaments that are too short to be visible by electron microscopy. This would be scored as a reduction in the number of F pili per cell [2,9].) The effects of mutations in traH, traF, and traW were similar (reference 14 and references therein).…”

Investigation of Bacteriophage MS2 Viral Dynamics Using Model Discrimination Analysis and the Implications for Phage Therapy

“…They are required in early stages of conjugal DNA transfer to establish specific and secure cell-cell contacts (42). In comparison with the other kinds of filaments, which are present at high multiplicities, only one or a few F-pili are present on an individual cell (19,43). Also, the occurrence of F-pili on the bacterial surface of E. coli changes under different growth conditions (43)(44)(45).…”

“…In comparison with the other kinds of filaments, which are present at high multiplicities, only one or a few F-pili are present on an individual cell (19,43). Also, the occurrence of F-pili on the bacterial surface of E. coli changes under different growth conditions (43)(44)(45). The concentration of F-pili in minimal medium is lower than in rich medium (43).…”

“…Also, the occurrence of F-pili on the bacterial surface of E. coli changes under different growth conditions (43)(44)(45). The concentration of F-pili in minimal medium is lower than in rich medium (43). All of the above stated reasons could explain the very low value of the adsorption constant in this study as compared to other phage-host systems (21,46).…”

Dual Reporter System for In Situ Detection of Plasmid Transfer under Aerobic and Anaerobic Conditions

“…This role is exemplified by the rapid spread of multidrug resistance (8) and the abundance of diverse transferable pollutant degradation plasmids (14). While many environmental factors are known to affect plasmid transfer efficiency (5), few studies have addressed the effect of oxygen levels on plasmid transferability, in spite of growing concerns about antibiotic resistance and virulence among facultatively and strictly anaerobic pathogens (2,3,10,12,13). There is thus an obvious need for new methods that allow quantitative analysis of plasmid transfer under both aerobic and anaerobic conditions.…”