Detection In The Acid-resistant Genes Ffh Of Veillonella Dispar

The product of the ffh gene is a kind of 5-kDa bioactive protein, which isthe homologue of the 54-kDa subunit of the eukaryotic signal recognitionparticle,and in Bacillus coli had found the 48KD product which has thesame function.Ffh has NG domain and M domain.The M domain provides the bindingmodule for 4.5S RNA,during the signal recognition particle (SRP)-dependenttargeting of proteins to the bacterial plasma membrane, the specific interactionbetween Ffh (the protein component of SRP) and FtsY (the SRP receptor) isknown to be essential for the efficiency and fidelity of this process.In free Ffh, the NG and M domains are facing one another in an orientationthat allows cross-linking between positions 231 in the G domain and 377 in theM domain. There are binding interactions between the two domains, as theisolated domains form a strong complex. The interdomain contacts aredisrupted upon binding of Ffh to 4.5S RNA, consuming a part of the totalbinding energy of 4.5S RNA-Ffh association that is roughly equivalent to thefree energy of domain binding to each other.Nobuyuki Shimohata examined the effects of ffh shutdown on export ofDsbA, using an engineered strain in which the ffh gene had been placed under arabinose promoter control . Cells were grown first in the presence ofarabinose and then in arabinose-free glucose medium to deplete Ffh.Real-time RT-PCR has become a powerful technique to monitorlow-abundance mRNA expression and is a useful tool when examiningbacterial gene expression inside infected host tissue.Gunnhild W Takle proved ffh to be the most stable set of reference genes underthe experimental conditions. They suggested ffh as a suitable candidatesforaccurate normalisation of real-time RT-PCR data for experiments investigatingthe plant pathogen P. atrosepticum and potentially other related pathogens.In my experiment,I get the standard veillonella dispar bacterium from vitroculture.We cloned the PCR product of veillonella dispar into the TA vector andselected the white clones. The recombinant plasmid was digested by HindⅢand pstⅠAmong those, there was one including the fragment of 700bp. Thenwe cultured the clone to extract the genome abundantly. After polymerasechain reaction, we obtained PCR product and sequenced it. We compared theproduct sequence with those from GenBank database. Compared by BLASTX,the highest identity was up to 100％。And the result was submitted to AmericanGenBank, and the accession number was EU551144.The sequence we obtainedin this study was a partial fragment. We would make a further research aboutthe open reading frame of the acid-resistant ffh gene of veillonella dispa in thefuture.We also obtained the unique PCR product in streptococcus sobrinus andfluoride-resistant strain of streptococcus sobrinus. But as the time was limited, we hadn't sequenced them. All these would be remained for further study.Now the acid-resistant gene ffh has bebome a hot issue. We study theacid-resistant reason of veillonella dispa from the gene level,make foundationfor molecular structure of the dental caries pathopoiesis,and it prepare toconstruct the vaccine for caries prevention.