Related Experiment Video
Updated: Aug 19, 2026

Quantitative Polymerase Chain Reaction (qPCR)-Based Rapid Diagnosis of Helicobacter pylori Infection and Antibiotic Resistance
Published on: July 28, 2023
Characterization of CagA variable region of Helicobacter pylori isolates from Chinese patients
Yong-Liang Zhu1, Shu Zheng, Qin Du
1Department of Gastroenterology, Second Hospital of Zhejiang University College of Medicine, Hangzhou, China.
Aim:
To characterize the CagA variable region of Helicobacter pylori isolates from Chinese patients.
Methods:
DNA fragments in CagA variable region were amplified and sequenced respectively from genomic DNA of 19 isolates from patients with gastric cancer and 20 isolates from patients with chronic gastritis. The tendency of phosphorylation in tyrosine(s) of CagA proteins was evaluated subsequently by phosphorylation assay in vivo and in vitro respectively.
Results:
About 97.44% (38/39) H pylori isolates possessed CagA gene. CagA(+) strains contained 2-4 tandem five-amino-acid motifs EPIYA but only one EPIYA had repeated sequence in CagA variable region in different isolates. There was no significant difference between the number of EPIYA motifs in H pylori from patients with different diseases. However, only tyrosine site in EPIYA within repeated sequence could be phosphorylated by AGS cells in vivo although all tyrosine sites in EPIYA could be phosphorylated in vitro.
Conclusion:
CagA in Chinese has no functional difference in perturbing cellular signal pathway among different H pylori isolates.
More Related Videos
05:23Gastric Mucosa Quantitative Polymerase Chain Reaction Analysis for Detecting Helicobacter pylori and Antibiotic Resistance
Published on: March 7, 2025
09:05High Resolution Electron Microscopy of the Helicobacter pylori Cag Type IV Secretion System Pili Produced in Varying Conditions of Iron Availability
Published on: November 21, 2014
Related Concept Videos
Gastritis II: Pathophysiology
Peptic Ulcer
Treating Helicobacter pylori in Peptic Ulcers: Antimicrobial Therapy