ABSTRACT
Porphyromonas gingivalis (Pg) is a kind of gram-negative obligate anaerobes. It can invade and internalize within host cells. The invasion ability of Pg is very important for the occurrence and development of diseases and has been a hot topic for a long time. Remaining pathogenic characteristics in cell is one of its pathogenesis. In the process of invading host, the specific bacterial adhesin combine with the ligand of host cells, which activate various signal transduction pathways and trigger bacterial internalization. Virulence factors in Pg, such as fimbriae, gingival protease, hemagglutinins and outer membrane vesicles play significant roles in the process. This review summarized the research progress of the virulence factors which relate to Pg′s invasion, which provided a serious of new ideas on exploring Pg′s pathogenesis and the prevention and treatment of related diseases.
ABSTRACT
FimA has been characterized as an important virulence factor for Porphyromonas gingivalis (Pg). These structures play a major role in the mechanisms of adhesion and invasion of Pg to host cells, and can induce cellular activation and cytokines release. FimA can also promote biofilm formation and induce immuno-inflammatory response of host cells. Many studies have characterized FimA to be associated with periodontitis and cardiovascular disease. Pg strains are classified into six types based on divergent nucleotide sequences of the fimA gene (types Ⅰ、Ⅰb、Ⅱ、Ⅲ、Ⅳ andⅤ). The expression of fimbriae is regulated by the fimA gene, which may be the key factor that leads to virulence diversities of Pg, At present, the research on the pathogenesis of FimA mainly focuses on periodontitis and atherosclerosis, which is of great significance for the prevention and treatment of diseases. This paper reviewed the pathogenic effect of FimA in the development of above mentioned two diseases and its application in the prevention.
ABSTRACT
BACKGROUND:In oral warm and moisture circumstance, al oy which contains Be is easily to be eroded to release Be2+. But there is stil no research focusing on beryl ium influence on genotype of Porphyromonas gingivalis fimbriae gene cluster. OBJECTIVE:To investigate Be 2+effect on genotype of Porphyromonas gingivalis fimbriae gene cluster. METHODS:The revived Porphyromonas gingivalis was resuscitated for 48 hours in the anaerobic culture medium with different concentration of Be 2+(10×10-6, 5×10-6, 1.25×10-6). Through PCR amplification and sequencing, we investigated the effects of Be2+RESULTS AND CONCLUSION:(1) When Be on genotypes of Porphyromonas gingivalis fimbriae gene cluster. 2+concentration was 5×10-6, we found the peak of 217 and 257 sites on DNA sequence expressing G/A overlap peak, different from G single peak of the other groups, suggesting the suspicious bases changes, part of the single base G mutated into A. (2) On al concentrations, we found a base group composed of seven A bases was inserted into the 101 site of DNA sequence. Up to now, there is no direct contacts of the mutations occurring to Be2+concentration. Changes of gene may lead to the shifting of the reading frame, the abnormal synthesis of proteins, the change of Porphyromonas gingivalis fimA gene toxicity, and lastly the unbalance of the micro-ecological environment.
ABSTRACT
Objective To investigate the association of esp, gelE, ebpA and QS-fsr system and biofilm formation in Enterococcus faecalis. Methods Totally 24 isolates of Enterococcus faecalis were collected from urine and catheter of clinical urine tract infection patients in Third Xiangya Hospital from Oct. 2007 to Jun. 2008, and were divided into biofilm group and non-biofilm group. The luminance ratios of esp, gelE, ebpA and fsrrB of Enterococcus faecalis in biofilm group and non-biofilm group were detected by RT-PCR. And the expression of esp, gelE, ebpA, fsrrB genes in different groups were detected by real-time PCR and were relatively quantitated through 2-△△Ct method. Moreover, the relevancies between that fourgenes and biofilm formation in Enterococcus faecalis were analyzed respectively. Results The expression of esp and ebpA in biofilm group were 298 times and 59 times more than the non-biofilm group. The expression level ofgelE and fsrB in biofilm group were 1/244 and 1/249 times less than the non-biofilm group, and the luminance ratios of esp, gelE, ebpA and fsrB were not significant between the two groups (rank sum was 92,79, 42 and 34 respectively,all P ＞ 0. 05 ). Conclusions The results showed that the biofilm formation in Enterococcus faecalis was promoted by esp and ebpA, and was inhabited by gelE and fsrB, which suggested that the expression of esp, ebpA and gelE genes was regulated by fsr system.