The Screening Of Oxalic Acid Degradation Bacteria And Its Function On Animal Model

Purpose:1. Screening with the degradation of oxalic acid capacity of lactic acid bacteriastrains from traditional fermented foods, and screening out the best lactic acid bacteriastrains by other functional assessment.2. To study the strains of the Preliminary safety.3. Observe the influence of target bacteria to a rat model of kidney stone disease.Method:1. Target strain preliminary screening, functional screening.Filter out lactic acid bacteria from the traditional fermented foods such as rice wine,preserved vegetables acquisition from Fujian, Sichuan and other regions of the country.Add the test strains to the MRS culture medium containing10%oxalic acid，culture48hand detect the residual content of oxalic acid in the fermentation broth. Elect six strainsas the candidate with the highest degradation rate of oxalic acid bacteria for furtherstudy. Functional screening of target strains includes acid-resistant，choline-resistant test,inhibitory test of target strain fermentation liquid on pathogenic bacteria, intestinalenzymes (trypsin, and pepsin)-resistant, HT-29colon cancer cell adhesion assay andantibiotic sensitivity test.2. The safety assessment tests of the target strains.The safety assessment tests of the target strains include: acute toxicity test,bacterial translocation test and the detection of the plasmid.3. The treatment effect on Kidney stone model of rat.Divide randomly wistar rats into four groups: normal control group, calciumoxalate stones models group, lactic acid bacteria with low dose intervention group,lactic acid bacteria with high dose intervention group. The construction of Wistar rats kidney stones model while gastricing lavage with milk fermentation liquid of targetstrains. The29day，determinations of the weight of the rats in each group, urine output,as well as calcium, oxalate ions, citric acid ion content, and making paraffin sectionsfrom rat left kidney to observe the stones occurrence of the experimental group.4. Identification of bacteriaDetermine the type of of bacteria.Results:1.344of lactic acid bacteria were screened out from traditional fermented foods.The following lactic acid bacteria are preliminarily screened for degradation of oxalicacid oxalic acid: DM8320, DM9207, DM9176, DM9147, DM9162, DM9172.Other functional screening results show that the DM9207, DM9147, DM9172havelower survival rate in different bile salt concentrations.DM9162have the low survivalrate in different pH mediun and the poor of the antibacterial effect of culturesupernatant.DM9176is resistant to many antibiotics. For these reasons, we choose theDM8320as the best strains, and follow-up test.2. In preliminary safety evaluation experiments, plasmids were not found in thestrain DM8320. Bacterias were not found in the homogenates of blood, liver, spleentissue.In virulence experiments, mice were normal activities, no toxicity or mortalityoccurred.3. In the rat kidney stone model intervention experiments, except the model group,control group, the weight change of high-dose intervention group andthe the low-doseintervention group showed an upward trend. The29days the body weight of rats resultsshowed that the stone model group,compared to control group, the intervention groupof high-dose and low dose in the intervention group, had the lower body weight (p<0.05). Compared to high-dose treatment group and stone group, the calcium, oxalateion content is lower in low-dose treatment group (p <0.05). Compared with high-dosetreatment group and low-dose treatment group, the gallstone group content the highercitric acid (p <0.05).Observe the paraffin sections of Kidney stones in the stone group, the rat kidneyparaffin sections contain different levels of kidney stones crystalline in low dosetreatment group and the high dose treatment group. The largest content of stones is inthe stone group, low dose treatment group is less, and the high dose treatment group isleast.4. Identificate the bacteria, the DM8320is the Lactobacillus reuteri. Conclusion:1. The strain DM8320, isolated from the344of Lactic acid bacteria in traditionalfermented foods, has the efficient in degradation of oxalic acid and good biologicalfunctions. The DM8320is the Lactobacillus reuteri.2. The strain DM8320doesn’t have acute toxicity, havn’t the phenomenon ofbacterial translocation in healthy mice and don’t contain plasmids.3. The strain DM8320inhibition to formation of wistar rat kidney stones.