Factors affecting genetic transformation of Neisseria gonorrhoeae

Abstract

Piliated gonococci were competent in genetic transformation in all stages of growth in minimal and enriched media, but nonpiliated cells were almost totally incompetent. Uptake of deoxyribonucleic acid into a deoxyribonuclease-insensitive state was observed only in competent piliated cells. Competence was not affected by washing of competent cells or treatment of competent cells with proteolytic enzymes. Expression of competence required presence of any of several different monovalent or divalent cations, as well as a utilizable source of energy. Efforts to produce genotypically or phenotypically competent derivatives of nonpiliated cells were unsuccessful. These experiments are consistent with the idea that pili may play a role in the irreversible uptake of transforming deoxyribonucleic acid by the gonococcus, but fail to provide evidence for other types of competence factors.

Characterization of pilQ, a new gene required for the biogenesis of type 4 fimbriae in Pseudomonas aeruginosa

“…Though the omc gene has not yet been associated with the assembly of pili in N. gonorrhoeae, its similarity to the P, aeruginosa pilQ gene suggests that this is a probable role. Another interesting connection exists between the omc gene and another member of the pulD family, N. gcnorrhoeae cells are naturally competent for transformation, though competence is greatly decreased in non-fimbriate cells (Biswas et al, 1977). H. influenzae cells are also naturally competent and DNA uptake in this species is dependent in part on a gene {ORFE) with homology to omc (Tomb etal.. 1991).…”

Common components in the assembly of type 4 fimbriae, DNA transfer systems, filamentous phage and protein‐secretion apparatus: a general system for the formation of surface‐associated protein complexes

“…More interestingly perhaps, the close similarity between these proteins and OR FE leads to the intriguing possibility that the Omc protein could be involved in both pilus assembly and DNA uptake (Martin et al, 1993), potentially explaining the correlation between piliation state and natural competence for DNA uptake in N. gonorrhoeae and a number of other type 4 fimbriated species (e .g. B0vre and Fmholm , 1972;Biswas et al, 1977), because both systems are using common components for their assembly or function .…”

PilT mutations lead to simultaneous defects in competence for natural transformation and twitching motility in piliated Neisseria gonorrhoeae

“…There is however, no direct evidence that transformation contributes as a mechanism to the impressive antigenic variability of pilin (Zhang et al, 1992). Gonococci express competence in a constitutive fashion (Biswas et al, 1977), unlike the situations in Bacillus subtilis, Streptococcus pneumoniae and Haemophilus influenzae in which competence development is a highly regulated and environmentally responsive event (Herriott et al, 1970;Magnuson et al, 1994;Havarstein et al, 1995). However, gonococci and H. influenzae are similar in that they show specificity for DNA uptake based on unrelated sequences of 10 and 11 bp, respectively, that are distributed throughout their genomes (Danner et al, 1980;Elkins et al, 1991).…”