Comparative Genomics ofH. pyloriand Non-PyloriHelicobacterSpecies to Identify New Regions Associated with Its Pathogenicity and Adaptability

Abstract

The genus Helicobacter is a group of Gram-negative, helical-shaped pathogens consisting of at least 36 bacterial species. Helicobacter pylori (H. pylori), infecting more than 50% of the human population, is considered as the major cause of gastritis, peptic ulcer, and gastric cancer. However, the genetic underpinnings of H. pylori that are responsible for its large scale epidemic and gastrointestinal environment adaption within human beings remain unclear. Core-pan genome analysis was performed among 75 representative H. pylori and 24 non-pylori Helicobacter genomes. There were 1173 conserved protein families of H. pylori and 673 of all 99 Helicobacter genus strains. We found 79 genome unique regions, a total of 202,359bp, shared by at least 80% of the H. pylori but lacked in non-pylori Helicobacter species. The operons, genes, and sRNAs within the H. pylori unique regions were considered as potential ones associated with its pathogenicity and adaptability, and the relativity among them has been partially confirmed by functional annotation analysis. However, functions of at least 54 genes and 10 sRNAs were still unclear. Our analysis of protein-protein interaction showed that 30 genes within them may have the cooperation relationship.

Genus-Wide Comparative Genomics Analysis ofNeisseriato Identify New Genes Associated with Pathogenicity and Niche Adaptation ofNeisseriaPathogens

“…In order to adapt to a variety of environments, bacteria have to change their genomes, but living in monotone habitats would have smaller pangenome [76]. Most of the Neisseria species colonize on the mucosa, which may be the reason that the pangenome size is relatively small compared with other niche diversity species [77, 78].…”

“…The power law regression analysis of pangenome found that both Neisseria genus and each Neisseria pathogen have open pangenome (Figure 3). Most of the Neisseria species colonize on the mucosa but in various individuals, which may lead to the open pangenome but relatively small size compared with other niche diversity species [77, 78]. Secondly, the number of UGNP, UGNMS, and UGNGS is 319, 78, and 452, respectively.…”

Genomics of Helicobacter pylori

“…The core and pan genomes of H. pylori were studied by Cao et al. that compared 75 H. pylori genomes and found an open and diverse core genome with 1173 conserved protein families and 673 conserved protein domains in the Helicobacter genus . Proposing that genome regions shared by at least 80% of the H. pylori and absent in non H. pylori may have a function in the adaptability and pathogenicity of H. pylori to the human host, they identified 79 such regions comprising 202,359 bp, among others coding for cag PAI, babB, and sabB .…”

Helicobacter pylori genotypes among Belarus patients with gastroduodenal disorders and their association with clinical outcome

“…The core and pan genomes of HP were studied by Cao et al [3] that compared 75 HP genomes and found an open and diverse core genome with 1,173 conserved protein families and 673 conserved protein domains in the Helicobacter genus.…”