Bacterial strains and plasmids used.

<p>^a Gmr, Apr, and Kmr = gentamycin, ampicillin, and kanamycin resistant, respectively; PCR = polymerase chain reaction.</p><p>^b Sources: Invitrogen Life Technologies, Carlsbad, CA, USA, Promega Corporation, Madison, WI, USA, EMD Millipore, Billerica, MA, USA,</p><p>Bacterial strains and plasmids used.