Identification of Contaminations Hiding Beneath theα- and β-Subunits of Partially Purified Nitrogenase MoFe Protein on the Sodium Dodecyl Sulfate Gel PCR AMPLIFYING AND SEQUENCING OF GgroEL GENE FROM ENDOSYMBIONTS IN Bemisia tabaci The Effects of Heterologous Expression of groEL from Arthrobacter simplex on the Resistance Performance of Escherichia coli