Research On Ferrous Ions Regulated The Expression Of Type Ⅵ Secretory System In Acinetobacter Baumannii

Objective To detect the effect of iron ion on the proliferation of Acinetobacter baumannii and the expression and regulation of type Ⅵ secretion system,and to analyze the relationship between the genotype expression of type Ⅵ secretion system of Acinetobacter baumanii and the effect of iron ion and to explore the effect of different concentrations of iron ion Effect of Time Period on the Expression of T6SS Related Genes in Acinetobacter baumannii.Methods The T6SS related genes of 59 strains of clinical pathogenic bacteria were detected by PCR and sequenced.The correlation between bacteria concentration and absorbance of Acinetobacter baumannii was established by autoregressive AR model(BaSO 4 standard curve method)SYBR Green qPCR method was used to detect the changes of gene expression of various components of Acinetobacter baumannii T6SS in different time periods with different concentrations of ions.ResuLts Among 42 strains of Acinetobacter baumannii,Hcp,VgrGl and VgrG2 genes were all positive(positive rate was 100%),TssA,TssB,TssC,TssE,TssE,TssG,TssH,TssK,TssL,TssM,TagF,TagN,Paar3,ClpV gene positive strains were 40,41,41,41,39,41,41,40,39,39,41,41,40 and 41;14 strains of Klebsiella pneumoniae Hcp,VgrGl,VgrG3 positive number of 12,13,14(positive rates were 85.7%,92.8%,100%respectively).The positive rates of other genes were all less than 80%.The autoregressive hybrid model was successful in modeling,and the BaSO4 standard can be used as an alternative to the Maxwell concentration calibrator.The maximum relative error was less than 5.04%.The model achieved a prediction of the proliferation concentration of Acinetobacter baumannii bacteria solution,and the results were in line with expectations.The results of different iron ion concentration(NB medium)at different time intervals showed that the inhibitory effect of iron ion on the expression of bacterial T6SS gene was relatively obvious under 48 μmol/L of Acinetobacter baumannii T6SS gene.The expression of T6SS gene has a regulatory effect.The regulation of different genes is different,indicating that the functions of T6SS genes of Acinetobacter baumannii are different,and TssE and other genes are closely related to the proliferation of bacteria.At the 2h and 8h time points,iron ion inhibited the expression of some T6SS genes,and most of the T6SS genes were inhibited strongly at 8 h.With the passage of time and the increase of the amount of bacteria,the expression of each T6SS gene was restored to the pre-suppressed level.Conclusion The gene sequence of Acinetobacter baumannii T6SS is relatively conservative with slight differences among different strains.AR model to assess the bacterial concentration relative to the turbidity method,higher accuracy,suitable for method substitution.Different concentrations of iron ion had different effects on the inhibition of T6SS in Acinetobacter baumannii:high and low concentrations of iron had no significant effect on the expression of T6SS in Acinetobacter baumannii,but within a certain concentration range(24 μmol/L,48 μmol/L)iron ions inhibited the expression of T6SS in A.baumannii.