LlaBIII,isolated from the naturally occurring plasmid pJW566 from Lactococcus lactis subsp.cremoris W56,encoded a restriction and modification (R/M) system. The plasmid pJK1 carrying the R/M system LlaBIII was transfo...LlaBIII,isolated from the naturally occurring plasmid pJW566 from Lactococcus lactis subsp.cremoris W56,encoded a restriction and modification (R/M) system. The plasmid pJK1 carrying the R/M system LlaBIII was transformed into L.lactis IL1403 with type I R/M system located on chromosome and the strain MG1614[pAW601] with AbiS gene on plasmid pAW601, respectively. The transformants obtained showed stacking resistance against bacteriophages. The plasmid pJK1 was transformed into industrial strains L.lactis SMQ86 and CHCC2281,the transformants showed the EOP of the bacteriophages decreased by 10 -3 and 10 -5, respectively.The results indicated that the R/M system LlaBIII could protect strains from bacteriophages in dairy fermentation.展开更多
Genomic sequences have been determined for a number of strains of Helicobacter pylori （H pylori） and related bacteria. With the development of microarray analysis and the wide use of subtractive hybridization techni...Genomic sequences have been determined for a number of strains of Helicobacter pylori （H pylori） and related bacteria. With the development of microarray analysis and the wide use of subtractive hybridization techniques, comparative studies have been carried out with respect to the interstrain differences between H pylori and inter-species differences in the genome of related bacteria. It was found that the core genome of H pylori constitutes 1111 genes that are determinants of the species properties. A great pool of auxiliary genes are mainly from the categories of cag pathogenicity islands, outer membrane proteins, restriction-modification system and hypothetical proteins of unknown function. Persistence of H pylori in the human stomach leads to the diversification of the genome. Comparative genomics suggest that a host jump has occurs from humans to felines. Candidate genes specific for the development of the gastric diseases were identified. With the aid of proteomics, population genetics and other molecular methods, future comparative genomic studies would dramatically promote our understanding of the evolution, pathogenesis and microbiology of Hpylori.展开更多
文摘LlaBIII,isolated from the naturally occurring plasmid pJW566 from Lactococcus lactis subsp.cremoris W56,encoded a restriction and modification (R/M) system. The plasmid pJK1 carrying the R/M system LlaBIII was transformed into L.lactis IL1403 with type I R/M system located on chromosome and the strain MG1614[pAW601] with AbiS gene on plasmid pAW601, respectively. The transformants obtained showed stacking resistance against bacteriophages. The plasmid pJK1 was transformed into industrial strains L.lactis SMQ86 and CHCC2281,the transformants showed the EOP of the bacteriophages decreased by 10 -3 and 10 -5, respectively.The results indicated that the R/M system LlaBIII could protect strains from bacteriophages in dairy fermentation.
文摘Genomic sequences have been determined for a number of strains of Helicobacter pylori （H pylori） and related bacteria. With the development of microarray analysis and the wide use of subtractive hybridization techniques, comparative studies have been carried out with respect to the interstrain differences between H pylori and inter-species differences in the genome of related bacteria. It was found that the core genome of H pylori constitutes 1111 genes that are determinants of the species properties. A great pool of auxiliary genes are mainly from the categories of cag pathogenicity islands, outer membrane proteins, restriction-modification system and hypothetical proteins of unknown function. Persistence of H pylori in the human stomach leads to the diversification of the genome. Comparative genomics suggest that a host jump has occurs from humans to felines. Candidate genes specific for the development of the gastric diseases were identified. With the aid of proteomics, population genetics and other molecular methods, future comparative genomic studies would dramatically promote our understanding of the evolution, pathogenesis and microbiology of Hpylori.
