Effect Of Rare Earth Salts On The Structure Of The Cell Wall Of The Staphylococcus Aureus

Aim of this research is to study the influence of some kinds of rare earth chloride salts on the cell wall structure of S. aureus. The action mechanism of rare earth ions on S.aureus is investigated at molecular level using SEM, TEM, IR,UV, 1HR-MAS and amino acid test. The results can be concluded as following:1. The minimum bacteria-inhibiting concentration and the minimum bactericidal concentration of rare earth on three bacteria were measured.2. Experimental results show that the rare earth ions break the cell wall structure of S.aureus. The break degree is connected with the positive concentration, the more the concentration is, the more the cell wall structure of S.aureus breaks .3. The results of IR and UV show that rare earth ions in the minimum bacteria-inhibiting concentration and minimum bactericidal concentration make most of the cell wall bonds destroy, and the same time, the netlike structure of peptidoglycan was broken, and the break degree is proportional to the concentration. Higher the concentration is, the stronger the effect is.4. The test of the amino acid in cell walls shows that the rare earth ion increase has the influence on the cell wall structure during bacterium growth process .The promotion or the destruction depend on its concentration. When the concentrations of ErCl3 and NdCl3 are below the bacteria-inhibiting concentration, they have promotion effect on the cell wall. It promotes the cell wall synthesis, and causes the amino acid content in the peptide polyose to increase, When the concentrations of ErCl3 and NdCl3 are larger than the bacteria-inhibiting concentration, they can destroy the synthesis of the cell wall, and causes the amino acid content in the peptide polyoses of the cell wall to reduce.5. The 1H-NMR test shows that rare-earth salts in bacteria-inhibiting consistence can destroy the hydrogen bond structure in the cell wall.We conclude that the bacteria-inhibiting mechanisms of rare earth ions on S.aureus is that rare earth ion breaks the cell wall structure.