Abstract: ObjectiveTo probe the effect of cell wall deficiency on urease and urease gene activity in Heliobater pylori.MethodsThe stable L-form of Heliobater pylori(H pyloria)were induced by ceftriaxone sodium and isolated with filtration and then subcultured in non-high osmotic medium without antibiotic.H pyloria and its L-forms were identified by PCR of 16srDNA.The UreA gene and UreB gene was amplified with the specific PCR primer and the PCR products were detected with agarose gel electroforesis.ResultsL-form H pyloria could be induced by ceftriaxone sodium in non-high osmotic liquid medium.The shape of L-form H pyloria were spherical or elliptical.The single or paired L-form H pyloriac arranged in chain or in pile.The stable L-forms could pass through the filter with 0.22μm aperture and be subcultured in the non-high osmotic liquid medium without antibiotic or other inducer.The 16SrRNA gene fragment could be amplified from the stable L-form H pyloria.The stable L-form derived from H pyloria had UreA gene and UreB gene with the same nucleotide sequence as that of their parental bacteria.ConclusionThe cell wall deficient mutation would happen when the H pyloria is treated with ceftriaxone sodium,and the pure culture of stable L-form strains could be isolated with filtration and then subcultured in nonhigh osmotic medium without antibiotic.The stable L-form strains derived from H pyloria have UreA and UreB gene with the same nucleotide sequence as that of their parental bacteria.