The Antibacterial Effect Of Lactobionic Acid On Staphylococcus Aureus

Lactobionic acid(LBA)is a natural polyhydroxy organic acid formed by microorganisms during lactose metabolism.It has been widely used in food,medicine and fine chemical industries due to its various biological functions.In recent years,the bacteriostatic properties of LBA have been gradually known,but the mechanism of bacteriostatic action has been rarely reported.Therefore,studying the antibacterial performance of LBA and its action mechanism on sensitive bacteria is of great practical significance for the prevention of foodborne diseases and food preservation caused by sensitive bacteria.Based on the bacteriostatic spectrum of LBA,this paper takes Staphylococcus aureus(S.aureus)as the research object,and examines the minimum inhibitory concentration(MIC)and minimum bactericidal concentration(MIC)and minimum bactericidal concentration(MBC)of LBA.At the same time,scanning electron microscope(SEM)and transmission electron microscope(TEM),atomic absorption spectrophotometer(Atomic absorption spectroscopy,AAS)were used to determine the growth of test bacteria.Conditions,nucleic acid leakage,relative conductivity,extracellular K~+,Na~+content,alkaline phosphatase leakage,and their effects on cell wall,cell membrane,and intracellular biosynthesis of macromolecules,and the use of i TRAQ technology to analyze lactobionic acid from test molecules Mechanism of action.the result shows:In the proteomic analysis,a total of 1747 proteins were identified.There were 274differentially expressed proteins,110 down-regulated differentially expressed proteins and164 up-regulated differentially expressed proteins.GO(Gene Ontology)enrichment analysis found that differentially expressed proteins are mainly involved in biological processes such as interspecies interaction between organisms,cell adhesion,biological adhesion,pathogenesis,modification of morphology orphysiology of other organism;cell component such as cell membrane,extracellular region,external encapsulating structure and cell wall;molecular function such as hydrolase activity,oxidoreductase activity and other molecular functions.KEGG(Kyoto Encyclopedia of Genes and Genomes)enrichment analysis found that differential proteins are mainly involved in the regulation of nitrogen metabolism,fatty acid degradation,valine,leucine and isoleucine degradation,chloroalkane and chloroalkene degradation,naphthalene degradation and ABC transporters and other important metabolic pathways.Protein interaction network analysis(PPI)analysis found that the connectivity of ABC transporters was the highest.After comprehensive analysis,it can be seen that LBA mainly destroys the cell wall integrity of S.aureus by regulating the two-component system(Gra SR)and over-expression of autolysin,and also has certain influence on cell wall damage repair function.The synthesis or expression of cell membrane proteins affects the integrity of the cell membrane,making the cell membrane unable to perform its normal physiological functions;reducing the adhesion and pathogenicity of S.aureus by destroying the surface proteins and virulence factors of the cells;LBA can also affects the energy metabolism of the cells by inhibiting the expression of ATP synthase,thereby regulating the expression of ABC transporter and reducing the tolerance of the cells to LBA;LBA can destroy the stress-related and starve-related proteins of the cells,so that they cannot respond and repair in time when the cells are damaged by structure and function,and they cannot provide additional energy.The regulation of ABC transporter by LBA plays a major role in the inhibition process.