The gene cluster for the biosynthetic of a nonribosomal peptide, cyanopeptolins and micropeptin (MCN), was identified in Microcystis strains and halogenated MCN-producing Microcystis were found to possess the halogena...The gene cluster for the biosynthetic of a nonribosomal peptide, cyanopeptolins and micropeptin (MCN), was identified in Microcystis strains and halogenated MCN-producing Microcystis were found to possess the halogenase gene, mcnD, between nonribosomal peptide synthetase genes, mcnC and mcnE. A comparative sequence analysis of the mcn gene cluster between halogenated and non-halogenated MCN-producing strains revealed mosaic sequence traces from mcnD in the non-coding region between mcnC and mcnE in the latter strains. A phylogenetic analysis based on a 170-bp non-coding region including the mcnD traces suggests that the recombination events occurred in a particular region of the Microcystis’ mcn gene. This study provides novel insight into the ecological patterning of widespread Microcystis species.展开更多
The purpose of this study was to demonstrate that actinomyces phage R4 integrase Sre protein efficiently mediate site-specific recombination in Escherichia coll. An intramolecular recombination assay system in E. coli...The purpose of this study was to demonstrate that actinomyces phage R4 integrase Sre protein efficiently mediate site-specific recombination in Escherichia coll. An intramolecular recombination assay system in E. coli was constructed. The plasmid pBZP contains attB and attP sites in direct orientation flanking a lacZ gene. When pBZP was introduced into E. coli cells, in which the plasmid pSREA containing sre gene was resident, Sre protein catalyzed integration of attP into attB site, resulting in excision of the lacZ gene. This integration changed bacteria colonies from blue to white on agar plates containing X-Gal, which showed that the lacZ was removed. The integrant DNAs were identified by enzyme digestion, PCR and DNA sequencing. The minimal sizes of attB and attP were 50 bp and 47 bp for 100% recombination efficiency. The phage recombinase Sre efficiently integrated attP into attB site to create attR and attL in E. coli host environment without Streptomyces specific cofactors. This intrmolecular assay system is a simple and efficient system for Sre-mediated recombination in E. coll.展开更多
文摘The gene cluster for the biosynthetic of a nonribosomal peptide, cyanopeptolins and micropeptin (MCN), was identified in Microcystis strains and halogenated MCN-producing Microcystis were found to possess the halogenase gene, mcnD, between nonribosomal peptide synthetase genes, mcnC and mcnE. A comparative sequence analysis of the mcn gene cluster between halogenated and non-halogenated MCN-producing strains revealed mosaic sequence traces from mcnD in the non-coding region between mcnC and mcnE in the latter strains. A phylogenetic analysis based on a 170-bp non-coding region including the mcnD traces suggests that the recombination events occurred in a particular region of the Microcystis’ mcn gene. This study provides novel insight into the ecological patterning of widespread Microcystis species.
文摘The purpose of this study was to demonstrate that actinomyces phage R4 integrase Sre protein efficiently mediate site-specific recombination in Escherichia coll. An intramolecular recombination assay system in E. coli was constructed. The plasmid pBZP contains attB and attP sites in direct orientation flanking a lacZ gene. When pBZP was introduced into E. coli cells, in which the plasmid pSREA containing sre gene was resident, Sre protein catalyzed integration of attP into attB site, resulting in excision of the lacZ gene. This integration changed bacteria colonies from blue to white on agar plates containing X-Gal, which showed that the lacZ was removed. The integrant DNAs were identified by enzyme digestion, PCR and DNA sequencing. The minimal sizes of attB and attP were 50 bp and 47 bp for 100% recombination efficiency. The phage recombinase Sre efficiently integrated attP into attB site to create attR and attL in E. coli host environment without Streptomyces specific cofactors. This intrmolecular assay system is a simple and efficient system for Sre-mediated recombination in E. coll.
