Project description:Sequencing of 16S ribosomal RNA (rRNA) gene, which has improved the characterization of microbial community, has made it possible to detect a low level Helicobacter pylori (HP) sequences even in HP-negative subjects which were determined by a combination of conventional methods. This study was conducted to obtain a cutoff value for HP colonization in gastric mucosa biopsies and gastric juices by the pyrosequencing method. Corresponding author: Department of Internal Medicine, Seoul National University Bundang Hospital, Seoungnam, Gyeonggi-do, Korea; Department of Internal Medicine and Liver Research Institute, Seoul National University College of Medicine, Seoul, Korea (Tel., +82-31-787-7008; e-mail, nayoungkim49@empas.com). Microbial DNA from gastric mucosal samples [gastric antrum (n=63, mucosal biopsy), follow-up sample on gastric antrum (n=16, mucosal biopsy), and gastric body (n=18, mucosal biopsy)] and gastric juices (n=4, not mucosal biopsy) was amplified by nested PCR using universal bacterial primers, and the 16S rRNA genes were pyrosequenced.
Project description:One microbial organism always contains multiple DNA modification systems as defense strategies or epigenetic controls. Here, we describe crosstalk between two distinct DNA modifications with different target sequence motif: DNA phosphorothioation (PT, GPSAAC/GPSTTC by DndACDE proteins) and N6-methyl-adenine methylation (m6A, G6mATC by Dam protein). By using a newly developed DNA modification sequencing method PT nick-seq, we found that half of PT modifications change from GAAC/GTTC to GATC sites after bacteria have lost Dam.