BACKGROUND:Streptococcus mutans is an important pathogen of dental caries,and timely detection of its levels is of great significance for early detection and treatment of dental caries. OBJECTIVE:To evaluate the effect of loop-mediated isothermal amplification(FTA-LAMP)direct extraction of Streptococcus mutans DNA. METHODS:(1)Bacterial suspensions containing ATCC standard strains(Streptococcus mutans)were prepared and inoculated into the brain-heart leachate medium.After mixed thoroughly,the mixture was then diluted in a 10-fold gradient into seven concentrations(4.2×107,4.2×106,4.2×105,4.2×104,4.2×103,4.2×102,4.2×10 CFU/mL),two parallel controls were made for each dilution level,and sterile water was used as a blank control.(2)The DNA of Streptococcus mutans was extracted using FTA Elute card,boiling method,kit extraction and lysate extraction methods separately and then amplified using LAMP technology was amplified.A specificity test was also performed to compare the differences between the four DNA extraction methods.RESULTS AND CONCLUSION:The DNA extracted by all four methods met the requirements for LAMP amplification.Specificity test results showed that only Streptococcus mutans could specifically amplify the target gene.The detection limit value of the DNA concentration was 4.2×103 CFU/mL for the lysate method,4.2×104 CFU/mL for the FTA Elute card extraction method,4.2×106 CFU/mL for the kit extraction method,and 4.2×107 CFU/mL for the boiling method.In the other aspects of the four extraction methods,the kit extraction method had the highest experimental cost,number of steps and time;the other three methods had the same number of steps,with the FTA Elute card method requiring the least amount of instruments,the boiling method having the lowest single cost,and the lysate extraction method taking the least amount of time.Only a small amount of bacteria were needed for successful extraction using both the FTA Elute card and lysate extraction methods.Compared with the FTA Elute card method,the lysate extraction method was superior in terms of time,but it had a high single cost and required more equipment.To conclude,the FTA-LAMP technology established in this study has the advantages of ease of operation,high specificity,high sensitivity,and visualization,which is expected to be a new way for efficient extraction and detection of Streptococcus mutans.

Paridis Rhizoma， a traditional valuable Chinese herbal medicine， has the functions of clearing heat and removing toxin， relieving edema and pain， cooling liver and calming convulsion， which can be used to treat various diseases such as mumps， abscess， burn， bleeding， and tumor. It has been used in folk medicine for a long time and is the main raw material of various Chinese patent medicines such as Gongxuening Capsules and Yunnan Baiyao. Polyphyllin Ⅰ， an isospirostanol saponin and one of the main active components in Paridis Rhizoma， is distributed in the rhizome， pericarp， and leaves of Paris polyphylla. With high polarity， polyphyllin Ⅰ is mainly extracted by n-butanol extraction and macroporous adsorption resin chromatography， separated by silica gel column chromatography and preparative high performance liquid chromatography， and purified with the combination of methods. With anti-tumor， anti-inflammatory， antibacterial， and anti-virus effects， it is generally employed to treat liver cancer， lung cancer， gastric cancer and other cancers as well as arthritis， influenza， sore toxin， and bacterial infection. However， polyphyllin Ⅰ may cause stomach irritation， hemolysis， liver damage， kidney damage， heart damage， and other adverse reactions. Pharmacokinetic studies show that it has problems such as low bioavailability and poor intestinal absorption and permeability， which affect the clinical application of polyphyllin Ⅰ. This paper summarizes the research on the plant sources， extraction and separation methods， pharmacological effects， adverse reactions， and pharmacokinetics of polyphyllin Ⅰ in recent years， which is expected to provide a reference for the rational clinical application and other in-depth research work of polyphyllin Ⅰ.