However , no significant differences were observed in fliN mRNA levels between isolates , suggesting that class 3 genes -LRB- controlled by FliA sigma factor -RRB- , but not class 2 genes , were affected .
However , no significant differences were observed in fliN mRNA levels between the two classes , suggesting that class 3 genes -LRB- controlled by FliA sigma factor -RRB- , but not class 2 genes , were affected .