Antioxidant Activity And Bioinformatics Study Of Extracellular Polysaccharides From Lactiplantibacillus Plantarum IMAU30043

Extracellular polysaccharides(EPS),as an important secondary metabolite of Lactiplantibacillus plantarum,have garnered significant attention from researchers in recent years due to its safety,non-toxicity,and properties such as antioxidant and anticancer abilities,texture improvement,and high nutritional value.Compared to synthetic antioxidants,EPS is a safe option for natural antioxidants when dealing with irreversible tissue damage and various diseases caused by oxidative stress.To study the antioxidant capacity and synthesis mechanism of new Lactiplantibacillus plantarum EPS,this thesis analyzed Lactiplantibacillus plantarum IMAU30043,IMAU40001,and IMAU80103,isolated and preserved from Xinjiang sour mare milk,which can produce high EPS.By assessing the in vitro EPS antioxidant activity,the most suitable strains were identified and,through bioinformatics techniques,the EPS gene cluster was examined to investigate the protective impact of EPS production on cellular oxidative damage.The findings of the study are presented below:1.3 strains of Lactiplantibacillus plantarum--IMAU30043,IMAU40001,and IMAU80103-were 223.6 mg/L,259.7 mg/L,and 186.0 mg/L,respectively;IMAU30043exhibits the most robust reduction capacity and a potent ability to scavenge superoxide anion and DPPH free radicals.2.Explored the protective effect of EPS produced by strain IMAU30043 on lipopolysaccharide-induced oxidative damage of RAW264.7 macrophages: EPS can significantly enhance cellular SOD activity following oxidative damage,reduce the content of MDA and NO,markedly suppress the gene expression of i NOS,TNF-α,IL-1β and IL-6,and significantly regulate the expression of IL-10.EPS has promoted the m RNA expression of Nrf2 and HO-1 in model cells,and inhibiting NF-κB activation,indicating a protective effect ithrough regulation of the Nrf2/HO-1/NF-κB pathway.3.The composition of IMAU30043 EPS was analyzed by ion chromatography: EPS produced by strain IMAU30043 was composed of fucose,rhamnose,galactose,glucose,xylose,mannose,glucuronic acid and mannuronic acidin a molar ratio of4.50:51.49:256.73:95.96:3.64:5.35:11.10:16.93.4.The genome of Lactiplantibacillus plantarum IMAU80122 was extracted and determine: The genome of IMAU30043 contains one chromosome DNA and seven circular plasmids.Three EPS gene clusters,consisting of 12.0 kp,12.3 kp and 9.7 kp in length respectively,were identified on chromosomes.This study comprehensively evaluated the in vitro antioxidant activity of Lactiplantibacillus plantarum IMAU40001,IMAU30043,and IMAU80103 in EPS production,and and identified IMAU30043 as the strain with the highest antioxidant activity.Furthermore,the cell oxidative damage repair effect and mechanism of action of its EPS were preliminarily analyzed,and its synthesis mechanism was explored.These findings provide a sound theoretical foundation and data support for the development and utilization of Lactiplantibacillus plantarum and its EPS.