title: Construction of a Helicobacter pylori genome map and demonstration of diversity at the genome level.
abstract: Genomic DNA from 30 strains of Helicobacter pylori was subjected to pulsed-field gel electrophoresis (PFGE) after digestion with NotI and NruI. The genome sizes of the strains ranged from 1.6 to 1.73 Mb, with an average size of 1.67 Mb. By using NotI and NruI, a circular map of H. pylori UA802 (1.7 Mb) which contained three copies of 16S and 23S rRNA genes was constructed. An unusual feature of the H. pylori genome was the separate location of at least two copies of 16S and 23S rRNA genes. Almost all strains had different PFGE patterns after NotI and NruI digestion, suggesting that the H. pylori genome possesses a considerable degree of genetic variability. However, three strains from different sites (the fundus, antrum, and body of the stomach) within the same patient gave identical PFGE patterns. The genomic pattern of individual isolates remained constant during multiple subcultures in vitro. The reason for the genetic diversity observed among H. pylori strains remains to be explained.
authors.affiliation: Department of Medical Microbiology and Infectious Diseases, University of Alberta, Edmonton, Canada.
authors.forename: D E
authors.initials: DE
authors.lastname: Taylor
authors.forename: M
authors.initials: M
authors.lastname: Eaton
authors.forename: N
authors.initials: N
authors.lastname: Chang
authors.forename: S M
authors.initials: SM
authors.lastname: Salama
mesh_terms: D001483:Base Sequence; D015342:DNA Probes; D004270:DNA, Circular / Q000235:genetics; D004275:DNA, Ribosomal / Q000235:genetics; D015252:Deoxyribonucleases, Type II Site-Specific / Q000378:metabolism; D016521:Electrophoresis, Gel, Pulsed-Field; D014644:Genetic Variation; D016680:Genome, Bacterial; D016480:Helicobacter pylori / Q000235:genetics*; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D012091:Repetitive Sequences, Nucleic Acid / Q000235:genetics; D015183:Restriction Mapping
chemical_list: D015342:DNA Probes; D004270:DNA, Circular; D004275:DNA, Ribosomal; C055654:endodeoxyribonuclease NruI; D015252:Deoxyribonucleases, Type II Site-Specific; C038565:GCGGCCGC-specific type II deoxyribonucleases