Analysis of single-nucleotide polymorphism of Sonic hedgehog signaling pathway in non-syndromic cleft lip and/or palate in the Chinese population / 北京大学学报(医学版)

OBJECTIVE@#To study the relationship between Sonic hedgehog (Shh) associated single-nucleotide polymorphism (SNP) and non-syndromic cleft lip and/or palate (NSCL/P), and to explore the risk factors of cleft lip and/or palate. Many studies suggest that the pathogenesis of NSCL/P could be related to genes that control early development, in which the Shh signaling pathway plays an important role.@*METHODS@#Peripheral blood was collected from 197 individuals (100 patients with NSCL/P and 97 healthy controls). Haploview software was used for haplotype analysis and Tag SNP were selected, based on the population data of Han Chinese in Beijing of the international human genome haplotype mapping project. A total of 27 SNP were selected for the 4 candidate genes of SHH, PTCH1, SMO and GLI2 in the Shh signaling pathway. The genotypes of 27 SNP were detected and analyzed by Sequenom mass spectrometry. The data were analyzed by chi-squared test and an unconditional Logistic regression model.@*RESULTS@#The selected SNP basically covered the potential functional SNP of the target genes, and its minimum allele frequency (MAF) was >0.05: GLI2 73.5%, PTCH1 91.0%, SMO 100.0%, and SHH 75.0%. It was found that the genotype frequency of SNP (rs12674259) located in SMO gene and SNP (rs2066836) located in PTCH1 gene were significantly different between the NSCL/P group and the control group. Linkage disequilibrium was also found on 3 chromosomes (chromosomes 2, 7 and 9) where the 4 candidate genes were located. However, in the analysis of linkage imbalance haplotype, there was no significant difference between the disease group and the control group.@*CONCLUSION@#In China, NSCL/P is the most common congenital disease in orofacial region. However, as it is a multigenic disease and could be affected by multiple factors, such as the external environment, the etiology of NSCL/P has not been clearly defined. This study indicates that Shh signaling pathway is involved in the occurrence of NSCL/P, and some special SNP of key genes in this pathway are related to cleft lip and/or palate, which provides a new direction for the etiology research of NSCL/P and may provide help for the early screening and risk prediction of NSCL/P.

Role of SMU.2055 gene in regulating acid resistance of Streptococcus mutans UA159 / 南方医科大学学报

<p><b>OBJECTIVE</b>To evaluate the effect of SMU.2055 gene on acid resistance of Streptococcus mutans.</p><p><b>METHODS</b>A SMU.2055-dificient mutant strain of S. mutans was constructed using homologous recombination technique. The growth of the wild-type and mutant strains was monitored in both normal and acidic conditions. The lethal pH level, glycolysis, proton permeability, cell permeability and biofilm formation of the two strains were compared.</p><p><b>RESULTS</b>PCR and sequence analyses verified the successful construction of the SMU.2055-dificient mutant strain. The growth and biofilm formation capacity of the mutant strain were obviously lowered in both normal and acidic conditions. The mutant strain also showed increased lethal pH level, proton permeability, and cell permeability with impaired H-ATPase activity in acidic conditions, but its minimum glycolytic pH remained unaffected.</p><p><b>CONCLUSION</b>The SMU.2055-deficient S. mutans mutant exhibits a lowered acid resistance, which affects the growth, lethal pH, proton permeability, H-ATPase activity, cell permeability and biofilm formation but not the minimum glycolytic pH of the mutant strain.</p>

Role of SMU.2055 gene in cariogenic capacity of Streptococcus mutans / 南方医科大学学报

<p><b>OBJECTIVE</b>To construct a SMU.2055-dificient mutant strain of Streptococcus mutans (S. mutans) and evaluate its cariogenic capacity in comparison with wild-type S. mutans.</p><p><b>METHODS</b>The SMU.2055-dificient mutant strain of S. mutans was constructed using homologous recombination technique and observed with scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The absorbance at 600 nm and pH values of the wild-type and mutant strains were monitored to evaluate their growth and acid production. After acid adaption, the two strains were challenged with acid shock and their survival rates were determined.</p><p><b>RESULTS</b>PCR and sequence analyses verified the successful construction of the SMU.2055-dificient mutant strain. Observation with SEM revealed obvious changes in the morphology of the mutant strain, which showed reduced irregular substances between the individual bacteria as compared with the wild-type strain. TEM revealed major alterations in the cellular architecture of the mutant strain with blurry cell membrane and disruption of the membrane integrity. The growth capacity of the mutant strain decreased in both normal and acidic conditions but its acid production capacity remained unaffected.</p><p><b>CONCLUSION</b>SMU.2055 gene is associated with morphology maintenance, growth capacity and acid resistance of S. mutans but is not related to the acid production capacity of the bacterium.</p>

Effects of intracellular Porphyromonas gingivalis on proliferation and osteogenic differentiation of human periodontal ligament cells in vitro / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the ability of Porphyromonas gingivalis to invade human periodontal ligament cells (hPDLCs) and the effect of intracellular P. gingivalis on cell proliferation and osteogenic differentiation in vitro.</p><p><b>METHODS</b>The invasion ability of P. gingivalis in hPDLCs was tested using an antibiotic protection assay at the multiplicity of infection (MOI) of 10 and 100. The proliferation of the infected cells was detected using a CFDA-SE kit, and the cells were sorted by fluorescence-activated cell sorting (FACS) followed by alizarin red staining for detecting mineralization nodules deposition; real-time PCR was used to examine the expression of Runx2 mRNA in the cells.</p><p><b>RESULTS</b>P. gingivalis actively invaded hPDLCs, and the internalized P. gingivalis was able to resist antibiotic treatment. The cells infected by P. gingivalis exhibited no significant suppression of cell proliferation, but showed significantly lowered capacity for osteogenic differentiation, down-regulated RUNX2 mRNA expression, and reduced mineral deposition.</p><p><b>CONCLUSION</b>Intracellular P. gingivalis does not significantly affect the proliferation of hPDLCs but inhibits osteogenic differentiation of the cells.</p>

Six degree-of-freedom acquisition and analysis of jaw opening and closing with motion capture system / 南方医科大学学报

<p><b>OBJECTIVE</b>To explore the six degrees of freedom of jaw opening and closing movement with motion capture and analysis system to establish a quantitative method for studying mandibular movement and a digital basis for virtual reality study of mandibular movement.</p><p><b>METHODS</b>In a male adult with normal dentition without temporomandibular joint disorders, 3 fluorescent markers were pasted in the upper dentition and 4 in the lower dentition. Six cameras of the motion capture system were arranged in a semi-circular fashion. The subject sat in front of the camera at an 80-cm distance with the Frankfort plane kept parallel to the horizontal plane. The degree-of-freedom (3 linear displacement and 3 angular displacement) of jaw opening and closing movement was obtained by collecting the marker motion.</p><p><b>RESULTS</b>Six degrees of freedom of jaw opening and closing were obtained using the motion capture system. The maximum linear displacements of X, Y and Z axes were 5.888 089 cm, 0.782 269 cm, and 0.138 931 cm, and the minimum linear displacements were -3.649 83 cm, -35.961 2 cm, -5.818 63 cm, respectively. The maximum angular displacements of X, Y and Z axes were 0.760 088°, 2.803 753°, and 0.786 493°, with the minimum angular displacements of -2.526 18°, -0.625 94°, and -25.429 8°, respectively. Variations of linear displacements during jaw opening and closing occurred mainly in the Y axis, and those of angular displacement occurred mainly in the Z axis.</p><p><b>CONCLUSION</b>The six degree-of-freedom of mandibular movement can be accurately obtained with the motion capture system to allow quantitative examination of the mandibular movement.</p>