Preliminary molecular analysis of bacterial composition in periapical lesions with primary endodontic infections of deciduous teeth / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>The bacterial composition of periapical lesions in deciduous teeth has not been well documented. This study was designed to explore the bacterial compositions, especially the dominant bacteria in periapical lesions using 16S rRNA sequencing.</p><p><b>METHODS</b>Tissue samples were collected from 11 periapical lesions in deciduous teeth with primary endodontic infections. DNA was extracted from each sample and analyzed using 16S rRNA cloning and sequencing for the identification of bacteria.</p><p><b>RESULTS</b>All DNA samples were positive for 16S rRNA gene PCR. One hundred and fifty-one phylotypes from 810 clones were identified to eight phyla, and each sample contained an average of 25.9 phylotypes. In addition, 59 phylotypes were detected in more than two samples, and Fusobacterium (F.) nucleatum (8/11), Dialister (D.) invisus (8/11), Campylobacter (C.) gracilis (7/11), Escherichia (E.) coli DH1 (6/11), Aggregatibacter (A.) segnis (6/11), and Streptococcus (S.) mitis (6/11) were the most prevalent species. Furthermore, 45 as-yet-uncultivated phylotypes were also identified.</p><p><b>CONCLUSIONS</b>Chronic periapical lesions in deciduous teeth contained polymicrobial infections. F. nucleatum, D. invisus, C. gracilis, E. coli DH1, A. segnis, and S. mitis were the most prevalent species detected by 16S rRNA sequencing.</p>

Sequence analysis of hemin-binding peptide derived from recombinant hemagglutinin-2 of Porphyromonas gingivalis / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To determine the sequence of the active peptide derived from recombinant hemagglutinin (rHA-2) of Porphyromonas gingivalis (Pg).</p><p><b>METHODS</b>The HA-2 gene from PgATCC33277 was cloned, expressed in Escherichia coli (Ec) BL21 (DE3), and purified. The purified recombinant protein was evaluated for its ability to bind hemin-linked agarose. The active peptide was subjected to endoproteinase-mediated sequence analysis.</p><p><b>RESULTS</b>The protein expressed in Ec BL21 (DE3) was identified as PgHA-2 by plasmid sequence analysis, Western blotting, and mass spectrometry. The recombinant protein was confirmed functional by its ability to bind hemin. The sequence of the active peptide of rHA-2 was determined to be DHYAVMISKTGTNAG.</p><p><b>CONCLUSIONS</b>The availability of sequence of the active peptide of rHA-2 provides a foundation for the development of immunoprophylactic and therapeutic agents against this human pathogen.</p>

Construction of the hemagglutinin-2-deficient mutant of Porphyromonas gingivalis / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To construct and identify the Porphyromonas gingivalis(Pg)ATCC33277 hemagglutinin-2(HA-2)-deficient mutant.</p><p><b>METHODS</b>The genomic DNA of Pg was isolated from PgATCC33277. The up/down stream genes of HA-2-HA(u), HA(l) were amplified by PCR, and inserted into pSY118 separately which contains a 2.1 kb antibiotic resistance ermF-ermAM cassette. The resultant recombinant plasmid-pSY118-HA was linearized as the gene targating fragment HA-ermF-ermAM and used in the electroporation of PgATCC33277. The Pg HA-2-deficient mutant was screened by allelic exchange. The test of aggregation of red blood cells was used to investigate the function change between PgHA2-deficient mutant and the wild type of PgATCC33277.</p><p><b>RESULTS</b>The PgHA-2-deficient mutant was identified by PCR. The ability of Pg HA-2-deficient mutant to aggregate red blood cell was significantly decreased compared with the wild type.</p><p><b>CONCLUSIONS</b>HA-2-deficient mutant of Pg ATCC33277 was constructed successfully, which lays a foundation for further study of its biological function.</p>