Investigating Potential Chromosomal Rearrangements during Laboratory Culture of Neisseria gonorrhoeae

Abstract

Comparisons of genome sequence data between different strains and isolates of Neisseria spp., such as Neisseria gonorrhoeae, reveal that over the evolutionary history of these organisms, large scale chromosomal rearrangements have occurred. Factors within the genomes, such as repetitive sequences and prophage, are believed to have contributed to these observations. However, the timescale in which rearrangements occur is not clear, nor whether it might be expected for them to happen in the laboratory. In this study, N. gonorrhoeae was repeatedly passaged in the laboratory and assessed for large scale chromosomal rearrangements. Using gonococcal strain NCCP11945, for which there is a complete genome sequence, cultures were passaged for eight weeks in the laboratory. The resulting genomic DNA was assessed using Pulsed Field Gel Electrophoresis, comparing the results to the predicted results from the genome sequence data. Three cultures generated Pulsed Field Gel Electrophoresis patterns that varied from the genomic data and were further investigated for potential chromosomal rearrangements.

Genomic Diversity and Chromosomal Rearrangements in <em>Neisseria Gonorrhoeae</em> and <em>Neisseria Meningitidis</em>

“…Unlike gonococcus, meningococcus can be present in the human nasopharyngeal mucosa without causing invasive disease. The literature mainly describes rearrangements in two pathogenic of Neisseria species [19][20][21][22][23][24][25]; in several studies, however, a comparative whole genome analysis of pathogenic and commensal Neisseria was carried out [26,27], in particular, to identify genome regions associated with virulence.…”

“…numerous chromosomal rearrangements occur, and the structural elements which are most often involved in rearrangements are repetitive sequences and prophages. To determine the time frame during which changes in the order of genes can occur, the rearrangements in N. gonorrhoeae strains exposed to stress factors ((39-41) o C, nalidixic acid) has been determined in laboratory conditions [25,32]. Structural rearrangements associated with CREEs and prophage-associated elements have appeared after 8 weeks of growing the culture under stress and reseeding every three days.…”

Genomic Diversity and Chromosomal Rearrangements in Neisseria gonorrhoeae and Neisseria meningitidis

“…To determine the time frame during which changes in the order of genes can occur, the rearrangements in N. gonorrhoeae strains exposed to stress factors ((39–41 °C), nalidixic acid) were determined in laboratory conditions [ 15 , 29 ]. Structural rearrangements associated with CREEs and prophage-associated elements appeared after 8 weeks of growing the culture under stress and reseeding every three days.…”