Identification of acquired DNA in<i>Neisseria lactamica</i>

Passel, Mark W. J. van; Bart, Aldert; Luyf, Angela C. M.; Kampen, Antoine H. C. van; Ende, Arie van der

doi:10.1111/j.1574-6968.2006.00366.x

Cited by 4 publications

(3 citation statements)

References 25 publications

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“…The low GC content of these genes suggests that they may have been acquired from an unrelated oropharyngeal bacterium. Other genes unique to N. lactamica , which may have been horizontally acquired after speciation, include four genes putatively involved in phosphorylcholine biogenesis ( licA , licB , licC and licD ), which may have been acquired by horizontal exchange from Haemophilus influenzae [69]; slpA , which encodes a putative AAA+ATPase, and slpB , which encodes a putative subtilisin-like protease; two low GC content genes that are present in a small number of N. lactamica strains and one Neisseria sicca strain [11]; and several genes that encode putative adhesins (Table 2). …”

Section: Comparison Of the Genome Sequence Of N Lactamica Isolate 02mentioning

confidence: 99%

Independent evolution of the core and accessory gene sets in the genus Neisseria: insights gained from the genome of Neisseria lactamica isolate 020-06

et al. 2010

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BackgroundThe genus Neisseria contains two important yet very different pathogens, N. meningitidis and N. gonorrhoeae, in addition to non-pathogenic species, of which N. lactamica is the best characterized. Genomic comparisons of these three bacteria will provide insights into the mechanisms and evolution of pathogenesis in this group of organisms, which are applicable to understanding these processes more generally.ResultsNon-pathogenic N. lactamica exhibits very similar population structure and levels of diversity to the meningococcus, whilst gonococci are essentially recent descendents of a single clone. All three species share a common core gene set estimated to comprise around 1190 CDSs, corresponding to about 60% of the genome. However, some of the nucleotide sequence diversity within this core genome is particular to each group, indicating that cross-species recombination is rare in this shared core gene set. Other than the meningococcal cps region, which encodes the polysaccharide capsule, relatively few members of the large accessory gene pool are exclusive to one species group, and cross-species recombination within this accessory genome is frequent.ConclusionThe three Neisseria species groups represent coherent biological and genetic groupings which appear to be maintained by low rates of inter-species horizontal genetic exchange within the core genome. There is extensive evidence for exchange among positively selected genes and the accessory genome and some evidence of hitch-hiking of housekeeping genes with other loci. It is not possible to define a 'pathogenome' for this group of organisms and the disease causing phenotypes are therefore likely to be complex, polygenic, and different among the various disease-associated phenotypes observed.

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Section: Comparison Of the Genome Sequence Of N Lactamica Isolate 02mentioning

confidence: 99%

Independent evolution of the core and accessory gene sets in the genus Neisseria: insights gained from the genome of Neisseria lactamica isolate 020-06

et al. 2010

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“…The commensal Neisseria are thought to be a reservoir of genetic material for the pathogenic strains, and plasmid transfer has been shown to occur between the pathogenic and commensal species (130,192,193). Plasmids are one way to exchange antibiotic-resistance elements and have contributed to β-lactamase (49) and tetracycline resistance in N. gonorrhoeae (112), as well as sulfonamide resistance in N. meningitidis (51,129).…”

Section: Plasmidsmentioning

confidence: 99%

The Genetics of Neisseria Species

2014

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Neisseria gonorrhoeae and Neisseria meningitidis are closely related organisms that cause the sexually transmitted infection gonorrhea and serious bacterial meningitis and septicemia, respectively. Both species possess multiple mechanisms to alter the expression of surface-exposed proteins through the processes of phase and antigenic variation. This potential for wide variability in surface-exposed structures allows the organisms to always have subpopulations of divergent antigenic types to avoid immune surveillance and to contribute to functional variation. Additionally, the Neisseria are naturally competent for DNA transformation, which is their main means of genetic exchange. Although bacteriophages and plasmids are present in this genus, they are not as effective as DNA transformation for horizontal genetic exchange. There are barriers to genetic transfer, such as restriction-modification systems and CRISPR loci, that limit particular types of exchange. These host-restricted pathogens illustrate the rich complexity of genetics that can help define the similarities and differences of closely related organisms.

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“…Genomic studies on N. lactamica have found regions of horizontally acquired DNA and the presence of many N. meningitidis virulence-associated genes [35], [36]. A few studies have analyzed the LOS produced by the commensal Neisseria and the data indicate that LOS heterogeneity extends beyond what is seen in the gonococcus and meningococcus [37], [38].…”

Section: Introductionmentioning

confidence: 99%

Sequence-Based Predictions of Lipooligosaccharide Diversity in the Neisseriaceae and Their Implication in Pathogenicity

et al. 2011

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Endotoxin [Lipopolysaccharide (LPS)/Lipooligosaccharide (LOS)] is an important virulence determinant in gram negative bacteria. While the genetic basis of endotoxin production and its role in disease in the pathogenic Neisseria has been extensively studied, little research has focused on the genetic basis of LOS biosynthesis in commensal Neisseria. We determined the genomic sequences of a variety of commensal Neisseria strains, and compared these sequences, along with other genomic sequences available from various sequencing centers from commensal and pathogenic strains, to identify genes involved in LOS biosynthesis. This allowed us to make structural predictions as to differences in LOS seen between commensal and pathogenic strains. We determined that all neisserial strains possess a conserved set of genes needed to make a common 3-Deoxy-D-manno-octulosonic acid -heptose core structure. However, significant genomic differences in glycosyl transferase genes support the published literature indicating compositional differences in the terminal oligosaccharides. This was most pronounced in commensal strains that were distally related to the gonococcus and meningococcus. These strains possessed a homolog of heptosyltransferase III, suggesting that they differ from the pathogenic strains by the presence a third heptose. Furthermore, most commensal strains possess homologs of genes needed to synthesize lipopolysaccharide (LPS). N. cinerea, a commensal species that is highly related to the gonococcus has lost the ability to make sialyltransferase. Overall genomic comparisons of various neisserial strains indicate that significant recombination/genetic acquisition/loss has occurred within the genus, and this muddles proper speciation.

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Identification of acquired DNA inNeisseria lactamica

Cited by 4 publications

References 25 publications

Independent evolution of the core and accessory gene sets in the genus Neisseria: insights gained from the genome of Neisseria lactamica isolate 020-06

Independent evolution of the core and accessory gene sets in the genus Neisseria: insights gained from the genome of Neisseria lactamica isolate 020-06

The Genetics of Neisseria Species

Sequence-Based Predictions of Lipooligosaccharide Diversity in the Neisseriaceae and Their Implication in Pathogenicity

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