Medini D

References (2)

Title : Neisseria meningitidis is structured in clades associated with restriction modification systems that modulate homologous recombination - Budroni_2011_Proc.Natl.Acad.Sci.U.S.A_108_4494
Author(s) : Budroni S , Siena E , Dunning Hotopp JC , Seib KL , Serruto D , Nofroni C , Comanducci M , Riley DR , Daugherty SC , Angiuoli SV , Covacci A , Pizza M , Rappuoli R , Moxon ER , Tettelin H , Medini D
Ref : Proc Natl Acad Sci U S A , 108 :4494 , 2011
Abstract : Molecular data on a limited number of chromosomal loci have shown that the population of Neisseria meningitidis (Nm), a deadly human pathogen, is structured in distinct lineages. Given that the Nm population undergoes substantial recombination, the mechanisms resulting in the evolution of these lineages, their persistence in time, and the implications for the pathogenicity of the bacterium are not yet completely understood. Based on whole-genome sequencing, we show that Nm is structured in phylogenetic clades. Through acquisition of specific genes and through insertions and rearrangements, each clade has acquired and remodeled specific genomic tracts, with the potential to impact on the commensal and virulence behavior of Nm. Despite this clear evidence of a structured population, we confirm high rates of detectable recombination throughout the whole Nm chromosome. However, gene conversion events were found to be longer within clades than between clades, suggesting a DNA cleavage mechanism associated with the phylogeny of the species. We identify 22 restriction modification systems, probably acquired by horizontal gene transfer from outside of the species/genus, whose distribution in the different strains coincides with the phylogenetic clade structure. We provide evidence that these clade-associated restriction modification systems generate a differential barrier to DNA exchange consistent with the observed population structure. These findings have general implications for the emergence of lineage structure and virulence in recombining bacterial populations, and they could provide an evolutionary framework for the population biology of a number of other bacterial species that show contradictory population structure and dynamics.
ESTHER : Budroni_2011_Proc.Natl.Acad.Sci.U.S.A_108_4494
PubMedSearch : Budroni_2011_Proc.Natl.Acad.Sci.U.S.A_108_4494
PubMedID: 21368196
Gene_locus related to this paper: neigo-pip , neima-metx , neime-ESD , neime-NMA2216 , neime-NMB0276 , neime-NMB1877

Title : Genome analysis of multiple pathogenic isolates of Streptococcus agalactiae: implications for the microbial pan-genome - Tettelin_2005_Proc.Natl.Acad.Sci.U.S.A_102_13950
Author(s) : Tettelin H , Masignani V , Cieslewicz MJ , Donati C , Medini D , Ward NL , Angiuoli SV , Crabtree J , Jones AL , Durkin AS , DeBoy RT , Davidsen TM , Mora M , Scarselli M , Margarit y Ros I , Peterson JD , Hauser CR , Sundaram JP , Nelson WC , Madupu R , Brinkac LM , Dodson RJ , Rosovitz MJ , Sullivan SA , Daugherty SC , Haft DH , Selengut J , Gwinn ML , Zhou L , Zafar N , Khouri H , Radune D , Dimitrov G , Watkins K , O'Connor KJ , Smith S , Utterback TR , White O , Rubens CE , Grandi G , Madoff LC , Kasper DL , Telford JL , Wessels MR , Rappuoli R , Fraser CM
Ref : Proc Natl Acad Sci U S A , 102 :13950 , 2005
Abstract : The development of efficient and inexpensive genome sequencing methods has revolutionized the study of human bacterial pathogens and improved vaccine design. Unfortunately, the sequence of a single genome does not reflect how genetic variability drives pathogenesis within a bacterial species and also limits genome-wide screens for vaccine candidates or for antimicrobial targets. We have generated the genomic sequence of six strains representing the five major disease-causing serotypes of Streptococcus agalactiae, the main cause of neonatal infection in humans. Analysis of these genomes and those available in databases showed that the S. agalactiae species can be described by a pan-genome consisting of a core genome shared by all isolates, accounting for approximately 80% of any single genome, plus a dispensable genome consisting of partially shared and strain-specific genes. Mathematical extrapolation of the data suggests that the gene reservoir available for inclusion in the S. agalactiae pan-genome is vast and that unique genes will continue to be identified even after sequencing hundreds of genomes.
ESTHER : Tettelin_2005_Proc.Natl.Acad.Sci.U.S.A_102_13950
PubMedSearch : Tettelin_2005_Proc.Natl.Acad.Sci.U.S.A_102_13950
PubMedID: 16172379
Gene_locus related to this paper: strag-ESTA , strag-GBS0040 , strag-GBS0107 , strag-GBS1828 , strag-pepx , strag-q3dah6 , strag-SAG0246 , strag-SAG0383 , strag-SAG0679 , strag-SAG0680 , strag-SAG0785 , strag-SAG0912 , strag-SAG1562 , strag-SAG2132